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Volume 93-B, Issue SUPP_IV November 2011

JY Lazennec A Ducat H Sarialli Y Catonne

Introduction: Wear performances and fracture toughness of the alumina-matrix composite (AMC) Biolox-delta® are pointed out in the literature. Clinical and radiological studies are needed to assess the potential benefits of AMC/AMC bearing surfaces. The aim of this study is the prospective evaluation of complications and risk factors in patients implanted with AMC liners and 32–36 mm AMC femoral heads.

Methods: 323 consecutive patients were included prospectively since 2006.

243 were implanted for primary surgery with 32 or 36 mm ball heads for a 10–12, 6° tapers.

In 80 cases, we used 32 and 36 mm Delta® sleeved heads (M,L,XL) for the adaptation on 12–14,5°43 tapers or 10–12, 6° tapers (acetabular revisions in absence of stem exchange, or to increase the lenght of the femoral neck and the offset) All the clinical and radiological files were evaluated at a minimum 2 years follow-up with a special attention for the fracture risk and squeaking. Radiological data were analysed using Dicomesure® software.

Results: We did not face any significant problem in this series. No fracture occurred. No abnormal wear or implants migration could be detected. We did not observe squeaking phenomenons. 2 THP were revised for septic complications ; the retrivials were analysed for transformation studies(Xray diffraction method XRD). The phase transformation tetragonal to monoclinic was mild, in accordance with previous experimental data.

Conclusion: The limitation of this study is its short follow-up; nevertheless the clinical results are in accordance with the previously published experimental data.


M.A. Swanson C. Schwan F. Gottschalk R. Bucholz M.H. Huo

The purpose of this study was to review the clinical and radiographic outcome in THRs done following acetabular fractures (fx). All patients undergoing conversion THR after previous acetabular fx between 1990 and 2006 at a single institution were identified.

Clinical evaluation was done using the Harris hip scale. Radiographic evaluation was done using the system proposed by the Hip society. THRs as part of initial treatment for acute acetabular fx were excluded.

There were 90 THRs (90 patients) performed in patients previously treated for an acetabular fracture. At the time of their acetabular facture, 67 had been treated with ORIF, 12 were treated with closed or limited open reduction and percutaneous fixation, and 11 were treated without surgery. The mean age at injury was 43.7 years, (range, 14–79). 68 patients sustained their fx from a high-energy mechanism (MVC, MPC, or MCC).

Three patterns accounted for 52% of the fx: transverse posterior wall (20), both column (18), and T-Type (9). Associated pelvic fractures were present in 14 patients. Associated ipsilateral proximal femur fractures were present: femoral head (four), femoral neck (five), and femoral shaft (three). Among those treated with ORIF, marginal impaction was noted in 31 and osteo-chondral head damage in 32 hips.

The mean interval between injury and THR was 42 months (range, two months to 32 years). Cement-less fixation was used in 81 of the 90 cups. Similarly, cementless stems were used in 80 stems. Bone graft was necessary in 26 patients (17 autograft, nine allograft). Two cases each required pelvic augments and reinforcement cage, respectively.

Additional findings at THR included: femoral head erosion (53 hips), femoral head osteonecrosis (37 hips), osteonecrosis of the acetabulum (22 hips), and fx non-union (six hips). The average cup abduction angle was 440 (range, 28 to 60), the average cup height was 24 mm (range, 10 to 42), and the average medialization distance was 23 mm (range, 5 to 48). The mean EBL was 810 ml and mean operative time was 195 minutes. The mean F/U was 36 months (range, 6 months to 17 years). The median Harris hip score was 89 at the most recent F/U. Fifteen revisions (16%) have been done: aseptic loosening (seven hips), recurrent dislocation (six hips) and infection (two hips).

Five of the six revisions for recurrent dislocation were performed in patients who had a posterior approach for both their acetabular fracture treatment and their THR. No revision was done in those who had been initially with percutaneous fixation. There was no infection in those who had been initially with percutaneous fixation either from the fx treatment or the THR. In contrast, 14 ORIF patients were complicated by infection. One of these developed infection following THR.

Our data support the clinical efficacy and mid-term durability of THR in this patient group. Aseptic loosening and recurrent dislocation remain the primary reasons for revision surgery.


D.J. Jacofsky J.D. McCamley M. Bhowmik-Stoker M.C. Jacofsky M.W. Shrader

Previous studies (Chen et al., 2003; Kaufmann et al., 2001) have shown that persons with osteoarthritis (OA) walk more slowly with lower cadence, have lower peak ground reaction forces and load their injured limb at a lower rate than healthy age matched subjects. However, another study (Mündermann et al., 2005) found that patients with severe bilateral OA loaded their knee joint at a higher rate. They also found these patients had higher knee adduction moments and lower hip adduction moments. It has been reported (McGibbon and Krebs 2002) that when subjects with knee OA are required to walk at the same speed as healthy subjects they generate more power at the hip joint to help overcome reduced knee power and aid in the advancement of the leg prior to the swing phase of the gait cycle. Myles et al. (2002) reported that patients with knee OA have reduced knee range of motion during walking. This paper presents detailed kinematic and kinetic data collected on a large group of patients with advanced knee osteoarthritis to show the differences in the gait of these patients just prior to surgery compared with age-matched control group.

This study was approved by the Sun Health Institutional Review Board. Subjects volunteered to participate in the study and signed informed consent prior to testing. Subjects were excluded if the had significant diseases of the other joints of the lower extremity or a diagnosed disorder with gait disturbance. Motion data was captured using a ten-camera motion capture system (Motion Analysis Corp., Santa Rosa, CA). Three-dimensional force data was recorded using four floor embedded force platforms (AMTI Inc., Watertown, MA). Patients were asked to walk at a self selected speed along a 6.5 meter walkway. A minimum of five good foot strikes for each limb were recorded. Data were collected using EVaRT 5 software (Motion Analysis Corp., Santa Rosa, CA) and analyzed using OrthoTrak 6.2.8 (Motion Analysis Corp., Santa Rosa, CA) and MatLab software (The Mathworks Inc., Natick, MA). Statistical analysis was performed using SPSS 14.0 software (SPSS Inc., Chicago, Il) (α = 0.05).

Eighty-six patients (71 ± 7 years) along with sixty-four control subjects (65± 10 years) volunteered to participate in the study. All measured temporal and spatial parameters showed significant differences between the OA patients and the control group. The OA patients were found to walk at a significantly lower velocity (p< .01) and cadence (p< .01) using a wider step width (p< .01) than the control subjects. Patients had their injured knee significantly more flexed at foot strike (p< .01) but flexed the knee significantly less during swing (p< .01) when compared to the control group. Patients had significantly higher knee flexion angles as well as hip flexion and abduction angles during stance. Knee varus angles were significantly higher for the OA patients during stance (p< .01) but not during swing when compared to the control group.

Significant increases in pelvic tilt and pelvic obliquity were measured during the stance phase. Hip abduction angles during stance were significantly lower for the OA group. Patients generated significantly lower vertical ground reaction forces during stance (p< .01) while sagittal plane kinetic analysis showed significantly lower external knee flexion moments (p< .01) and knee power generation (p< .01) during this phase of the gait cycle. Analysis of frontal plane angles showed OA patients had a significantly higher maximum knee varus angle during stance as well as generating a higher external knee varus moment (p=.03) during this phase of the gait cycle.

Changes in gait measured in this study support and enhance findings from previous studies. OA patients appeared to walk with a more crouched posture with higher knee and hip flexion angles through mid stance. This along with lower velocity and cadence and a larger step width would indicate a desire for more stability while walking. Patients also flexed their knees more at foot strike in an attempt to absorb the forces generated during weight acceptance. While knee flexion angles measured for the OA group were similar to the control subjects during the initial period of stance, the OA patients did not extend their knees as much during mid stance indicating a desire to reduce the angular rotation of the knee while in single support. Changes measured in frontal plane angles of the hip and pelvis may be an attempt to compensate for the different angles generated by the knee during stance. The differences in hip and knee angles measured during stance for patients and controls allowed patients to have reduced peak external knee flexion moments during initial stance but a higher knee flexion moment at mid stance. The reduction in knee angular change during stance and the reduced cadence meant power absorption during early and late stance and generation during mid stance was much lower for the OA patients than the control group. All the changes noted appear to be designed to limit the movement of the knee joint while loaded and reduce the peak loads in an effort to reduce pain at the affected joint while at the same time increase stability during gait. These data show the differences that exist between the gait patterns of patients with advanced osteoarthritis and healthy age-matched persons and highlight the changes that are necessary following knee replacement surgery and rehabilitation to return the gait of these patients to normal.


W. L. Buford F. M. Ivey D. M. Loveland C. W. Flowers

Past work in our laboratory identified the generalized effects of TKA on muscle balance, showing a significant change in relative moment generating potential balance favoring flexion and external rotation relative to the normal (intact) knee (for both PCL sparing and posterior stabilized TKA). However, there are no reliable data descriptive of the effect of any single prosthesis. This study hypothesized that using a modern TKA (Smith Nephew Journey) and implantation by a single surgeon in five fresh cadaver specimens would result in change in muscle balance similar to the earlier results for posterior stabilized TKA.

Using the tendon excursion-angular motion method (MA = dr/dΘ, r is excursion, Θ is joint angle in radians), moment arms of all muscles at the knee were determined for each of three conditions (intact, ACL-deficient, and prosthesis). The moment arms were then multiplied by the known muscle tension fractions to generate each muscle’s relative moment potential for each specimen across the three conditions. The resultant summed total moment potential was then examined for differences in the flexion-extension (FE) and internal-external (IE) rotation components.

There was no significant difference in either FE or IE component for intact versus either the ACL deficient condition (FE, p=0.62, IE, p=0.49) or arthroplasty (FE, p=0.99, IE, p=0.82). TKA agreed more closely with the intact knee. Thus, we reject the hypothesis that a modern TKA (Journey) performs as projected by past generic results, and conclude that modern TKA effectively reconstructs the balance of the intact knee.

This improves prospects for rehabilitation following TKA.


T. Kabata T. Maeda T. Murao K. Tanaka H. Yoshida Y. Kajino T. Horii S. Yagishita K. Tomita

Objective: The treatment of osteonecrosis of the femoral head (ONFH) in young active patients remains a challenge. The purpose of this study was to determine and compare the clinical and radiographic results of the two different hip resurfacing systems, hemi-resurfacing and metal-on-metal total-resurfacing, in patients with ONFH.

Materials and Methods: We retrospectively reviewed 20 patients with 30 hips with ONFH who underwent hemi-resurfacing or total-resurfacing between November 2002 and February 2006. We mainly performed hemi-resurfacing for early stage ONFH, and total-resurfacing for advanced stage. Fifteen hips in 11 patients had a hemi-resurfacing component (Conserve, Wright Medical Co) with the mean age at operation of 50 years and the average follow-up of 5.5 years. Fifteen hips in 10 patients had a metal-on-metal total-resurfacing component (Birmingham hip resurfacing, Smith & Nephew Co.) with the mean age at operation of 40 years and the average follow-up of 5 years. Clinical and radiographic reviews were performed.

Results: The average postoperative JOA hip scores were 86 points in hemi-resurfacing, 96 points in total-resurfacing. The difference of pain score was a main factor to explain the difference of total JOA hip score in the two groups. Both implants were radiographically stable, but radiolucent lines around the metaphyseal stem were more frequent in total-resurfacing. In hemi-resurfacing patients, ten of 15 hips had groin pain or groin discomfort, three hips were revised to total hip arthroplasties (THA) because of femoral neck fracture, acetabular pro-trusio, and osteoarthritic change, respectively. On the other hand, in total-resurfacing patients, there were no revision and no groin pain.

Discussion: In the prosthetic treatment of young active patients with ONFH, it is theoretically desirable to choose an implant with conservative design in anticipation of the future revision surgery. Hemi-resurfacing hip arthroplasty is the most conservative implant for the treatment of ONFH. However, the results of hemi-resurfacing in this study have been very disappointing due to high revision rates and insufficient pain relief despite of the good implant stability. On the other hand, the pain relief and implant survivorship after total-resurfacing were superior to the results of hemi-resurfacing, although the usages of the total-resurfacing were for more advanced cases. These results suggested that total-resurfacing was a more valuable treatment option for active patients with ONFH than hemi-resurfacing


C. Manders A.M. New M. Taylor

During hip replacement surgery the hip centre may become offset from its natural position and it is important to investigate the effect of this on the musculoskeletal system. Johnston et al [1] found that medialisation of the hip centre reduced the hip joint moment, hip contact and abductor force using a musculoskeletal model with hip centre displacements in 10mm increments. More recently an in vivo study found that the range of displacement of the hip centre of rotation was from 4.4mm laterally to 19.1mm medially [2]. To investigate the hypothesis that medialisation of the hip centre reduces the hip contact force, a musculoskeletal model of a single gait cycle was analysed using three scenarios with the hip in the neutral position and with it displaced by 10mm medially and laterally.

The lower limb musculoskeletal model included 162 Hill type muscle units in each leg and uses a muscle recruitment criterion based on minimising the squared muscle activities, where the muscle activity is the muscle force divided by the muscle’s maximum potential force. The maximum potential force is affected by the length of the muscle unit and the muscle’s tendons each are calibrated to give the correct length in its neutral position. The same gait analysis data from one normal walking cycle was applied to each modelled scenario and the resultant hip joint moment, hip contact force and muscle forces were calculated. The abductor muscles forces were summed and the peak force at heel strike reported. The peak resultant hip moments and the peak hip contact forces at heel strike are also reported and compared between the different scenarios. The scenarios were each run twice, once with the muscle tendon lengths calibrated for the hip in the altered position and subsequently with the muscle tendon lengths maintained from the neutral hip position.

For the medialising of the femoral head, the hip contact force and the peak abductor force were reduced by 4% and 2% respectively compared the neutral position. However if the tendon lengths of the muscles were maintained from the neutral position, the medial displacement model had a 3% higher hip contact force and a 6% larger abductor force than calculated for the neutral position. Although the peak resultant hip joint moment increases with a lateral displacement by 3%, the peak abductor force and peak hip contact force have a reduced force of 3% compared to the neutral hip. Using the muscle tendon lengths calibrated for the hip in the original position produces a 3% increase in the hip contact and abductor force for the lateralised femoral head.

This study has shown that the hip contact force and abductor force depend on the calibration of the muscle’s tendon lengths. Using the model with muscles calibrated for the altered hip centre produced the hypothesed reduction in hip contact force. However, maintaining the tendon lengths from the neutral position had a significant effect the calculated forces. The hip contact and abductor forces increased in the models with the original tendon lengths and the effect was also found to be greater when the hip was displaced medially.


J. M. Johnson M.R. Mahfouz

Accurate segmentation of bone structures is an important step in surgical planning. Patient specific 3D bone models can be reconstructed using statistical atlases with submillimeter accuracy. By iteratively projecting noisy models onto the bone atlas, we can utilize the statistical variation present in the atlas to accurately segment patient specific distal femur and proximal tibia models from the CT data.

Our statistical atlas for the knee consists of 199 male distal femur models and 71 male proximal tibia models. We performed an initial registration between the average model from the atlas and the volume space before beginning the segmentation algorithm. Intensity profiles were linearly interpolated along the direction normal to the surface of the current model. The profiles were then smoothed via a low-pass filter. A point-tonearest peak gradient was calculated for each profile, and then weighted by a Gaussian window centered about the originating vertex. The flesh-to-bone edge locations are taken as the maximum of the weighted gradient. The detected locations were then projected onto the atlas using a subset of the available principal components (PC’s). The amount of variation is increased by projecting the edge locations onto a larger subset of PC’s. The process is repeated until 99.5% of the statistical variation is represented by the PC’s. Though our dataset is much larger, we initially performed bone segmentation on 5 male knee joints. The knee joint was considered to be the distal femur and proximal tibia. We used manually segmented models to determine ground truth. Initial results on the 5 knee joints (distal femur and proximal tibia) had a mean RMS error of 1.192 mm, with a minimum of 1.010 mm. Segmentation on the distal femur achieved a mean RMS error of 1.213 mm, and the results for the tibia had a mean RMS error of 1.264 mm.

Our results suggest that our atlas-based segmentation is capable of producing patient-specific 3D models with high accuracy, though patient-specific degeneration was often not well represented. To achieve more accurate patient-specific models, we must incorporate local deformations into the final model.


H.E. Cates R.E. Barnett S.M. Zingde M.A. Schmidt R.D. Komistek M.R. Anderle M.R. Mahfouz

Previous fluoroscopic analyses of Total Hip Arthroplasty (THA) determined that the femoral head slides within the acetabular cup, leading to separation of certain aspects of the articular geometries. Although separation has been well documented, it has not been correlated to clinical complications or a more indepth understanding of the cause and effect. Surgical technique is one of the important clinical factors when considering THA procedures, and it is hypothesized, that it could affect the magnitude and occurrence of femoral head separation (sliding) in THAs. Hence, the objective of this study was to determine and compare in-vivo THA kinematics for subjects implanted with a THA using two different surgical approaches.

Thirty seven subjects, each implanted with one of two types of THA were analysed under in vivo, weight-bearing conditions using video fluoroscopy while performing a sit-to-stand activity. Ten subjects were implanted by Surgeon 1 using a long incision postero-lateral approach (G1); while a further 10 subjects were implanted by the same surgeon using a short incision posterolateral approach (G2). The remaining 17 subjects were implanted using the anterolateral approach; 10 by Surgeon 2 (G3) and seven by Surgeon 3 (G4). All patients with excellent clinical results, without pain or functional deficits were invited to participate in the study (HHS > 90). 3D kinematics of the hip joint was determined, with the help of a previously published 2D-to-3D registration technique. From a completely seated position to the standing position, four frames of the fluoroscopy video were analysed.

Subjects in all groups experienced some degree of femoral head separation at all increments of the sit-to-stand activity that were analysed. The magnitude and frequency of separation greater than 1.0mm varied between each surgeon group, between incision types, between incision lengths and between the two types of THA that were analysed. The average maximum separation was 1.3, 1.1, 1.3 and 1.4mm for G1, G2, G3 and G4 respectively. Though there was no difference in the average maximum separation values for the 4 groups, the maimum separation varied significantly. While the maximum separation in G2 was 1.8mm, the maximum separation in G4 was 3.0mm. G1 and G3 had maximum separation values of 2.3mm and 2.4mm respectively.

This study suggests that there may be a correlation between incision lengths and surgical approach with femoral head separation in THAs. The maximum separation that was seen among all groups was a subject with a traditional long incision, while the short incision group had less incidence of separation. Results from this study may give researchers and implant developers a better understanding of kinematics around the hip joint and how they vary with respect to different surgical techniques. Further analysis is being conducted on the subjects before definitive conclusions can be made.


GA Higgins Z Morison M Olsen EH Schemitsch

Surgeons performing hip resurfacing ante-vert and translate the femoral component anterior to maximize head/neck offset and educe impingement. The anterior femoral neck is under tensile forces during gait similarly to the superior neck [6]. This study was esigned to determine the risk of femoral neck fracture after anterior or posterior notching of the femoral neck.

Method: Fortyseven 4th generation synthetic femora were implanted with Birmingham Hip Resurfacing pros-theses (Smith & Nephew Inc. emphis, USA). Implant preparation was performed using imageless computer navigation (VectorVision SR 1.0, BrainLAB, Grmany). The virtual prosthesis was initially planned for neutral version and translated anterior, or posterior, to create the notch. The femora were fixed in a single-leg stance and tested with axial compression using a mechanical testing machine. This method enabled comparison with previously published data. The synthetic femora were prepared in 8 experimental groups:2mm and 5mm anterior notches, 2mm and 5mm posterior notches, neutral alignment with no notching (control), 5mm superior notch, 5mm anterior notch tested with the femur in 25° flexion and 5mm posterior notch tested with the femur in 25° extension We tested the femora flexed at 25° flex-ion to simulate loading as seen during stair ascent. [3] The posterior 5mm notched femoral necks were tested in extension to simulate sporting activities like running. The results were compared to the control group in neutral alignment using a one-way ANOVA:

Results: Testing Group Mean load to failure Significance Neutral (Control) 4303.09 ± 911.04N Anterior 2mm 3926.62 ± 894.17N p=0.985 Anterior 5mm 3374.64 ± 345.65N p=0.379 Posterior 2mm 4208.09 ± 1079.81N p=1.0 Posterior 5mm 3988.07 ± 728.59N p=0.995 Superior 5mm 2423.07 ± 424.16N p=0.003 Anterior 5mm in 25° flexion 3048.11 ±509.24N p=0.087 Posterior 5mm in 25° extension 3104.61±592.67N p=0.117 Both the anterior 5mm notch tested in single-leg stance and anterior notch in flexion displayed lower compressive loads to failure (3374.64N and 3048.11N). The mean load to failure value for the posterior 5mm notches in extension was 3104.62N compared to 4303.09N for the control group. Our data suggests that anterior and posterior 2mm notches are not statistically significantly weaker in axial compression. The anterior 5mm notches tend towards significance in axial compression (p=0.38) and bordered significance in flexion (p=0.087). The 5mm posterior notches were not significantly weakened in axial compression (p=0.995), but tended towards significance in extension (p=0.117). The 5mm superior notch group was significantly weaker with axial compression supporting previous data published (p=0.003). We are currently assessing offset and other variables that may reduce data spread.

Conclusion: We conclude that anterior and posterior 2mm notching of the femoral neck has no clinical implications, however 5mm anterior notches may lead to fracture. The fracture is more likely to occur with stair ascent rather than normal walking. Posterior 5mm notches are not likely to fracture with normal gait, but may fracture with higher impact activities that promote weight bearing in extension. Hip resurfacing is commonly performed on active patients and ultimately 5mm notching in the anterior or posterior cortices has clinically important implications.


E. E. Abdel Fatah M. R. Mahfouz L N. Bowers

Fracture of the distal radius is one of the most common wrist fractures that orthopedic surgeons face. Quite often an injury is too severe to be repaired by supportive measures and pin or plate fixation is the subsequent alternative. In this study we present a novel method for automated 3D analysis of distal radius utilizing statistical atlases, this method can be used to design pin or plate fixation device that accurately fit the anatomy.

A set of 120 bones (60 males and 60 females) were scanned using high resolution CT. These CT scans were then segmented and the surface models of the radius were added to the statistical atlas. Global shape differences between males and females were then identified using the statistical atlas. A set of landmarks were then calculated including the tip of the lateral styloid process and centroid of the distal plateau. These landmarks were then used to calculate the width of the distal plateau, the height of the distal plateau, overall radius length and the curvature of the distal plateau. These measurements were then compared for both males and females. Three of the measurements came statistically significant with p< 0.01. Curvature of the distal plateau wasn’t found to be significant, with females having slightly higher radius of curvature than males.

This automated 3D analysis overcomes the major drawbacks of 2D x-ray measurements and manual localization methods. Thus, this analysis quantifies more accurately the anatomical differences between males and females. Statistically significant anatomical gender differences were found and quantified, which can be used for the design of trauma prosthesis that can fit normal anatomy.


A. Palermo G. Calafiore M. Rossoni R. Simonetta

The return to the use of big diameter femoral heads is now a well-established reality.

The certainty of a better result is not only for young patients with an high functional demand, but also for elderly people, who need a reduction of enticement time and an increase of intrinsic Materials optimization and “hard to hard” bearings allowed surgeons to reduce the problem of volumetric wear and to guarantee some undeniable advantages such as: -better articular stability, thanks to the off-set restore -better range of motion -reduction of dislocation risk Increasing the femoral head diameter means increasing the off-set therefore the lever arm of the gluteus medius which is a great articular stabilizer. With the old metal to polyethylene and ceramic to polyethylene bearings, the bigger contact surface between the head and the cotyle interior certainly increased the volumetric wear in the past. The introduction of bearings at “low friction coefficient” ceramic-to-ceramic and metal-to-metal solved this problem and the undeniable improvement of the polyethylene preparation made this material to be considered safe even with big diameter heads. All articular stability parameters, in primis for the off-set, can be improved by the use of those solutions which are all efficient and able to give the surgeon the right mean to solve every single case.

The eventuality to break ceramic heads is reported in literature and has fortunately reference to a low percentage, about 1.5% (“Biolox 28 mm ceramic-ceramic THR: 1.5% fractures 7 years f.u.” Toni, Alt.Bearings, NYC, 2002), but it maybe limits this kind of choice in cases of hip dysplasia, in which a bigger acetabulum uprightness increases the percentage of mistake in placing the cotyle. Nowadays, the diameter of the available heads is progressively increasing with the cotyle diameter (32, 36), so ceramic-ceramic is anyway an excellent solution for all other fatigued coxofemural articulations, above all if they are still eumorphic, and for female patients in which a worst bone quality reduces the choice of metal-metal.

The metal-metal bearing finds instead a great indication in all patients, above all male patients with a good bone quality with high functional demand. The only reasons to go back preferring the metal-metal bearing are the reduction of the average age of the prosthesized patient and the increasing performance need. New techniques of superficial finish of the chrome-cobalt allowed surgeons to optimize the clearance, the self-smoothing ability in case of “streaks” of third body.

Tests drawn in gate analysis demonstrated a reduced detachment between the two prosthesis components when the metal-metal operated patient makes the step, not only in favour of the bearing, but also of the choice of big diameters (“Metal on metal and distraction: an in vivo comparison.” Komistec et al; JBJS; October 2002). Moreover, other indications in literature show that there is no direct correlation between the cancer development and the metal-metal bearing prosthesis implant (Visuri, COOR 1996) (“The risk of cancer following total hip or knee arthroplasty” Tharani et al., JBJS May 2001), and even that there were no cobalt toxic serum levels able to justify cardio-pneumatie (Brodner, JBJS 1997). Independently by the materials choice, the bearing with big diameter heads undeniably reduces dislocation risk and accelerates the post-operative recovery even in old patients surgically treated for fracture.

The larger distance a big diameter head has to cover in order to come out of the acetabular cavity (Jump distance) certainly reduces the number of dislocation cases.

(“Large versus small femoral heads in metal on metal total hip arthroplasty” –Cucler J.M. et al., JoA, Vol 19, num 8, suppl. 3., 2004) (“Effect of femoral head diameter and operative approach on risk of dislocation after primary total hip arthroplasty” Berry DJ et al., JBJS Am. 2005 Nov; 87(11):2456–63).

All those reasons pushed us to believe in “hard to hard” bearings with big diameter, whose results could not be more satisfying. Nevertheless, there are some complications which can make us think, such as cases of pseudocancer for metal-metal bearing and the squeaking in the ceramic-ceramic bearing. The introduction of last generation polyethylene could bring the golden standard near the ceramicpolyethylene again.


Robert E. Booth

Orthographic radiography, a revelation at its inception, has been the orthopaedic standard for a century. It has facilitated osteology and empowered arthroplasty like no other parallel technology. While many new imaging modalities – nuclear scans, computerized axial tomography, magnetic resonance imaging, etc. – have advanced the art even further, plain XRays, quite frankly, remain the standard for identifying patient pathology and evaluating surgical intervention. The enlightened scrutiny of properly obtained and successfully reproduced radiographic images still yields far more information in the daily practice of orthopaedics than its more sophisticated and expensive derivatives. A detailed review of readily available diagnostic information is intended to rejuvenate/resuscitate our most valuable ally in the evolving struggle against arthritic disease.


C.S. Ranawat

The three distinct phases of design and development of total knee replacement (TKR) were:

1969–1985,

1986–2000 and

2000 to today and beyond.

Hinge designs and early condylar designs highlight the first major period of TKR development from 1969 to 1985. These designs included but were not limited to the Waldius, Shiers, and GUEPAR hinges, Gunston’s Polycentric Knee in 1971, Freeman’s ICLH Knee in 1972, Coventry’s Geomedic Knee in 1972, St. George’s Sled Prosthesis in 1971, Marmor’s Modular Uni in 1971, Townley’s Condylar Design in 1972, Walker and Ranawat’s Duocondylar in 1971, Waugh’s UCI Knee in 1976, Eftekar’s Metal Backing in 1978, Murray and Shaw’s Metal Backed Variable Axis Knee in 1978, Insall and Burstein’s IB-1 Knee in 1978, the Kinematics in 1978, and finally Walker, Ranawat and Insall’s Total Condylar in 1978.

The Total Condylar Knee, developed by Walker, Ranawat, and Insall between 1974 and 1978, has been the benchmark for all designs through the 20th century. My personal experience of cemented TKR from 1974–2009 has shown a survivorship of 89%–98% at 15–20 years. Similar data has been presented in several 10+ year follow-up studies.

The next major phase of development gave birth to semi-constrained TKR, cruciate saving and substituting PS designs, improved instrumentation and improved cemented fixation. Other guiding principles involved improving alignment, managing soft-tissue balance for varus-valgus deformity, improving kinematics and producing superior polyethylene for reduced wear and oxidation. The advent of rotating platform mobile bearing knees with multiple sizes marked the most recent major advancement in TKR design.

With more total knee replacements being performed on younger, more active patients, improved design, better fixation (non-cemented), and more durable articulation are needed. The new standard for ROM will be 125 degrees. Non-cemented fixation, improved poly, such as E-poly, and the rotating platform design will play a major role in increasing the longevity of TKR to over 25 years.


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G.R. Scuderi

John N. Insall accomplished unparalleled success as an orthopedic surgeon, implant designer, and teacher. Over a span of 4 decades he was a pioneer in the field of knee surgery and was instrumental in evolving total knee arthroplasty to its current state of excellence. His legacy in total knee implant design began with the Duocondylar and Duopatellar prosthesis; was revolutionary with the implantation of the first Total Condylar Prosthesis -the first modern prosthesis; followed by posterior cruciate ligament substitution with the Insall – Burstein Posterior Stabilized Prosthesis; and ultimately with the Legacy Posterior Stabilized High Flexion Prosthesis – a fixed and mobile bearing high performance implant. Recognizing the importance of surgical technique with any implant design, Insall simultaneously described the surgical technique of ligament releases for restoring axial alignment and balancing the flexion and extension gaps. Over time his innovations have been embraced by the majority of surgeons and have become the foundation of what we do today. During more than 40 years of clinical practice, John N. Insall was an unselfish educator. He shared his clinical experiences with the medical community by publishing, along with his students and associates, an exhaustive array of articles and books on various afflictions of the knee. Recognized by his contemporaries as a leader in the field of total knee arthroplasty, he was elected president of the Knee Society in 1987. For the entire orthopedic community he continued to work laboriously, sharing his experiences with his fellows and colleagues until his death in 2000. The life of John N. Insall will be remembered in perpetuity for his unparalleled influence on knee surgery.


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D.J. Berry

Sir John Charnley unquestionably was the pioneer of modern joint arthroplasty. He was also an innovator in many other areas of orthopedics, including fracture care and arthrodesis, but this tribute will focus on his contributions to arthroplasty.

Charnley pioneered the use of methyl methacrylate cement and in so doing provided the first reliable means of fixing implants to bone. For the first time, this provided arthritis patients with reproducible long-term, reliable pain relief from advanced joint arthritis. Charnley also pioneered the use of a novel bearing surface, high molecular weight polyethylene. In so doing, he pioneered resurfacing of both sides of a joint with a low-friction, low-wear bearing. This provided the potential for excellent pain relief and also durable function of a hip arthroplasty.

Charnley understood the importance of reproducing joint mechanics and kinematics, and the arthroplasties he designed fully reproduced leg length and hip offset, and therefore the mechanics of the hip.

Finally, Charnley understood that technology is only a great value when it can be transferred effectively to many surgeons around the world. He created a carefully constructed educational structure to teaching the methodology in a way that would allow surgeons to practice this procedure successfully in other centers. Charnley understood the importance of minimizing complications for a procedure to be widely adopted and successful.

It is no exaggeration to state that Charnley’s contributions have helped tens of millions of patients worldwide who otherwise would have been permanently crippled by arthritis. Today’s further advances in joint arthroplasty are all dependent on the foundations of joint arthroplasty pioneered by Sir John Charnley.


P. Bergschmidt C. Lohmann R. Bader C. Lukas W. Ruether W. Mittelmeier

The objective of this prospective duo-center study was to evaluate the clinical and radiological outcome of the unconstrained Multigen Plus total knee system (Lima Lto, San Daniele, Italy) with the new BIOLOXÒ Delta ceramic femoral component.

40 patients underwent cemented total knee arthroplasty in two university hospitals. Clinical evaluations were undertaken preoperatively and at 3 as well as 12 months postoperatively using the HSS-Score, WOMAC-Score and SF-36-Score. The radiological investigations included ant-post. radiographs (whole leg in two leg stance and lateral view of the knee) and patella tangential radiographs (Merchant view).

During 12 months follow-up three patients underwent revision surgery. One patient had to be revised due to infection after postoperative opening of the knee joint due to direct trauma. One patient sustained an osteosynthetic procedure due to periprosthetic fracture after trauma. In one patient a retropatellar replacement was inserted one year postoperatively. Implant related complications were not found. The mean preoperative HSS-Score amounted to 57.8±11.7 points. At 3 and 12 month follow-up the mean HSS-Score was 76.0±12.3 and 83.3±11.9 points respectively.

Therefore HSS, as well as WOMAC and SF-36 Score improved significantly from preoperativly to both postoperative evaluations (Wilcoxon-Test p< 0.002). Radio-lucent lines around the femoral ceramic component were found in six cases.

However, subsequent long-term studies must be carried out in order to prove the good early clinical results and to clarify if progression of radiolucent lines may influence the clinical outcome of the presented newly ceramic total knee system.


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WL Bargar

Hap Paul was a unique individual. It is appropriate that this award should go a unique paper presented at this year’s ISTA. The name “Hap” comes from his initials Howard A. Paul. He was an outstanding veterinarian, but he was also much more than that. He had an insatiable curiosity combined with a quick mind and a surgeon’s practicality. His first love was research. After graduating from high school in Connecticut, he went to Notre Dame as a swimmer. He graduated with a degree in Microbiology and a strong desire to “cure cancer”. Acting on his dreams, as he always did, he decided to go to Paris to work with one of the pioneers of Interferon research. Never mind that he didn’t have a job and did not know a word of French. Of course he got the job and learned French playing rugby (hence his awful accent and colorful vocabulary). The funding ran out for the Interferon research, but he somehow got a shot at a spot in the veterinary school in Paris. He got married and finished his veterinary training. The veterinary thing worked out, but the marriage didn’t. He returned to the US after 9 years living in France, to attend the UC Davis School of Veterinary Science as a surgical resident in the small animal area. He met his wife, Dr. Wendy Shelton there… but that is another story.

I met Hap when I was a new attending orthopaedic surgeon at UC Davis and looking to do some animal modeling of hip replacement revision techniques. He was an imposing figure: six feet four, big curly afro and wire glasses. He dressed like a Frenchman, wore big clogs and carried a purse. Needless to say I was intimidated initially. But, he had great joi de vive and lived up to his name… he was almost always happy.

Hip replacement in dogs began in the 1970’s, but was nearly abandoned by the early 1980’s because of infections and “luxations” (dislocations). In order to develop an animal model we had to develop instruments and techniques that incorporated “third generation” cementing techniques. This we did, but Hap took these instruments and began using them clinically on working dogs. He developed quite a reputation for resurrecting hip replacements for dogs in the US and internationally. Hap and I went on to develop dog models for CT-based custom implants and later surgical robotics (eventually leading to the development of Robodoc). Despite our academic interests, both Hap and I went into private practice in the mid 1980’s… separately, of course (he as a veterinary orthpaedic surgeon and I specialized in hip and knee replacements for humans). Our research in surgical robotics took off when we landed a huge grant from IBM. But then the sky fell in when we learned that Hap had developed lymphoma. After surgery, radiation and chemotherapy, he was in remission, but temporarily couldn’t perform surgery due to a peripheral neuropathy attributed to Vincristine. So Hap went to the lab at UC Davis to work directly with the robotics team. He was a slave driver… but a pleasant one. Certainly the basic research behind Robodoc could not have been done without Hap getting lymphoma.

Over 5 years (1986–91) we both had a ball working with some of the best minds in robotics and imaging research. We presented our research on CT-based customs and robotics at many international venues, and Hap made many friends… some are in the audience today. He was one of the founders of this organization (ISTA). Hap returned to veterinary practice when he could finally work with his hands again… but this was not for long. Soon our research lead to the founding of Integrated Surgical Services (ISS) in 1991, the makers of Robodoc. Hap agreed to leave his practice to lead the company and I stayed in clinical practice to develop and utilize the device on patients. In 1992, we shocked the world by being the first to use an active robot in human surgery. It looked like the dawning of a new age. (I still believe it is, but it has been a very slow dawn).

For Hap, the joy was short-lived. He developed leukemia as a complication of his prior chemotherapy. He died while recovering from a bone marrow transplant on Feb. 10, 1993 at the young age of 44. During his short life he contributed tremendously to the benefit of others by his research and development work. But mostly he inspired others to excel in their endeavors. He was a wonderful guy. And we are all pleased to honor him with the presentation of the Hap Paul Award at each year’s meeting of ISTA.


E. Chimoto Y. Hagiwara Y. Saijo A. Ando H. Suda Y. Onoda E. Itoi

Introduction: Acoustic microscopy for medicine and biology has been developed for more than twenty years at Tohoku University [18]. Application of acoustic microscopy in medicine and biology has three major features and objectives. First, it is useful for intra-operative pathological examination because staining is not required. Second, it provides basic acoustic properties to assess the origin of lower frequency ultrasonic images. Third, it provides information on biomechanical properties at a microscopic level because ultrasound has close correlation with mechanical properties of the tissues. This paper describes the preliminary results obtained using 300 MHz ultrasound intensity microscopy for in vitro characterization of rat synovial cell cultures. The novelty of the approach lies in the fact that it allows remote, non-contact and disturbance-free imaging of cultured synovial cells and the changes in the cells’ properties due to external stimulants such as transforming growth factor beta-1 (TGFbeta1).

Materials and Methods: Ultrasound intensity microscope: An electric impulse was generated by a high speed switching semiconductor. The electric pulse was input to a transducer with sapphire rod as an acoustic lens and with the central frequency of 300 MHz. The reflections from the tissue was received by the transducer and were introduced into a Windows-based PC (Pentium D, 3.0 GHz, 2GB RAM, 250GB HDD) via a digital oscilloscope (Tektronix TDS7154B, Beaverton, USA). The frequency range was 1GHz, and the sampling rate was 20 GS/s. Four values of the time taken for a pulse response at the same point were averaged in order to reduce random noise. The transducer was mounted on an X-Y stage with a microcomputer board that was driven by the PC through RS232C. The Both X-scan and Y-scan were driven by linear servo motors. The ultrasound propagates through the thin specimen such as cultured cells and reflects at the interface between the specimen and substrate. A two-dimensional distribution of the ultrasound intensity, which is closely related to the mechanical properties, was visualized with 200 by 200 pixels.

Tissue preparation: The synovial membrane was obtained from non-operated male rats weighing from 380 to 400 g through medial parapatellar incision. The tissue was diluted and loosened 0.15% DispaseII (Boehringer, Mannheim) in DMEM for 2 hours at 37 C°. Then centrifuged at 400 g for 5 min and discard the supernatant. The cells were plated in 75 mm2 dish (Falcon) with Dulbecco’s modified Eagle’s medium (DMEM, GIBCO Laboratories) containing 10% fetal bovine serum (SIGMA Chemical Co.) at 37 C° in a CO2 incubator. To determine changes of intensity, the cells were treated with 1 ng/ml of human recombinant TGF-β1 (hTGF-β1, R& D Systems, Inc.) for 1 and 3 days after reaching confluent. The non-treated cells was harvested at 3 days after reaching confluent and defined as control. Randomized four points at each dish were measured and averaged data was defined as the representative value of each dish. The cells used for experiments were at the third passage.

Signal processing: The reflection from the tissue area contains two components. One is from the tissue surface and another from the interface between the tissue and the substrate (phosphate buffered saline). Frequency domain analysis of the reflection enables the separation of these two components and the calculation of the tissue thickness and intensity by Fourier-transforming the waveform [9].

Image analysis: Randomized point regions were determined using ultrasound intensity microscopic images. This was done by employing commercially available image analysis software (PhotoShop CS2, Adobe Systems Inc.). Ultrasound intensity microscopic images with a gradation color scale were also produced for clear visualization of the ultrasound intensity variations.

Statistics: Statistical analysis among groups was performed using one factor analysis of variance. Data were expressed as mean ± standard deviation. A value of P < 0.05 was accepted as statistically significant.

Results: The ultrasound intensity microscope can clearly visualize cells. The high intensity variations area of the reflected ultrasound energy at the central part of the cell corresponded to the nucleus and the high intensity area at the peripheral zone corresponded to the cytoskeleton mainly consisting of actin filaments. The intensity of the reflected ultrasound energy at the peripheral zone was significantly increased after stimulation with hTGF-b1.


A. Speranza E. Monaco M. Vetrano C. D’Arrigo A. Ferretti

The choice of surgical technique for total hip arthroplasty (THA) can affect time and postoperative rehabilitation procedures. The aim of this prospective blinded cohort study is to determine significant differences in gait parameters in the short term between those patients who have experienced THA using a limited incision anterolateral intermuscular (MIS) approach compared with those who have experienced traditional lateral transmuscular (LTM) approach.

Thirty patients were enrolled in this study, 15 of who received the MIS technique and 15 the LTM approach. A single surgeon performed all the operations using short hip stem implants with 36mm femoral head size and all patients received a standard postoperative rehabilitation protocol. Patients, physiotherapists, and assessors were blinded to the incision used. Gait analysis was performed 30 day after surgery, when patients were able to ambulate without crutches.

Minimal differences in temporostatial parameters were shown between the MIS and LTM groups, whereas significant differences (p< 0.05) in kinematics (hip range of motion in sagittal, frontal and transverse planes), kinetics (hip flexion/extension and abduction/adduction moments) and electromiography parameters (gluteus medius activation pattern and degree of activity) between two groups.

This study demonstrates functional benefits of the minimally invasive incision over the standard lateral transmuscular approach in terms of walking ability 30 days postoperatively.


A.S. Dickinson M. Browne A.C. Taylor

Although resurfacing hip replacement (RHR) is associated with a more demanding patient cohort, it has achieved survivorship approaching that of total hip replacement. Occasional failures from femoral neck fracture, or migration and loosening of the femoral head prosthesis have been observed, the causes of which are multifactorial, but predominately biomechanical in nature. Current surgical technique recommends valgus implant orientation and reduction of the femoral offset, reducing joint contact force and the femoral neck fracture risk. Radiographic changes including femoral neck narrowing and ‘pedestal lines’ around the implant stem are present in well performing hips, but more common in failing joints indicating that loosening may involve remodelling. The importance of prosthesis positioning on the biomechanics of the resurfaced joint was investigated using finite element analysis (FEA).

Seven FE models were generated from a CT scan of a male patient: the femur in its intact state, and the resurfaced femur with either a 50mm or 52mm prosthesis head in

neutral orientation,

10° of relative varus or

10° of relative valgus tilt.

The fracture risk during trauma was investigated for stumbling and a sideways fall onto the greater trochanter, by calculating the volume of yielding bone. Remodelling was quantified for normal gait, as the percentage volume of head and neck bone with over 75% post-operative change in strain energy density for an older patient, and 50% for a younger patient.

Resurfacing with the smaller, 50mm prosthesis reduced the femoral offset by 3.0mm, 4.3mm and 5.1mm in varus, neutral and valgus orientations. When the 52mm head was used, the natural joint centre could be recreated rrespective of orientation, without notching the femoral neck. The 50mm head reduced the volume of yielding femoral neck bone relative to the intact femur in a linear correlation with femoral offset. When the natural femoral offset was recreated with the 52mm prosthesis, the predicted neck fracture load in stumbling was decreased by 9% and 20% in neutral and varus orientations, but remained in line with the intact bone when implanted with valgus orientation. This agrees with clinical experience and justifies currently recommended techniques. In oblique falling, the neck fracture load was again improved slightly when the femoral offset was reduced, and never fell below 97% of the natural case for the larger implant in all orientations.

Predicted patterns of remodelling stimulus were consistent with radiographic clinical evidence. Stress shielding increased slightly from varus to valgus orientation, but was restricted to the superior femoral head in the older patient. Bone densification around the stem was predicted, indicating load transfer. Stress shielding only extended into the femoral neck in the young patient and where the femoral offset was reduced with the 50mm prosthesis. The increase in remodelling correlated with valgus orientation, or reduced femoral offset. The trend would become more marked if this were to reduce the joint contact force, but there was no such correlation for the 52mm prosthesis, when the natural femoral offset was recreated. Only in extreme cases would remodelling alone be sufficient to cause visible femoral neck narrowing, i.e. patients with a high metabolism and considerably reduced femoral offset, implying that other factors including damage from surgery or impingement, inflammatory response or retinacular blood supply interruption may also be involved in femoral neck adaptation.

The results of this FEA biomechanical study justify current surgical techniques, indicating improved femoral neck fracture strength in stumbling with valgus position. Fracture risk under oblique falling was less sensitive to resurfacing. Furthermore, the results imply that reduced femoral offset could be linked to narrowing of the femoral neck; however the effects of positioning alone on bone remodelling may be insufficient to account for this. The study suggests that surgical technique should attempt to recreate the natural head centre, but still aim primarily for valgus positioning of the prosthesis, to reduce the femoral neck fracture risk.


W.N. Capello

At ten years, alumina ceramic bearings are functioning well with low complication rates and a fewer number of revisions than the control cohort.

Alumina ceramic bearings have proven superior wear resistance, lubrication, and scratch resistance, without carrying the risk of metal ion release. In 1996 a U.S. IDE clinical trial was initiated utilizing newly improved alumina ceramic materials and implant design. The purpose of this multi-center, prospective, randomized study is to prove comparable safety and efficacy of alumina-alumina ceramic to a control cobalt chrome-polyethylene bearing.

Four hundred fifty two patients (475 hips) are followed in this study. Subjects include ceramic on ceramic, with either porous coated cup or arc deposited cup, or control group with metal on polyethylene with porous coated cup. Average age of subject at time of surgery was 53 years with 82% diagnosis of OA. The average Harris Hip Score was 96 and 94% of hips had little to no pain. Kaplan-Maier survivorship at 10 years, component revision for any reason, was 95.9% for ceramic bearings compared to 91.3% for metal on polyethylene control. There have been nine hips requiring revision of one or both components for any reason.

Data was recently collected on the subjects that participated in either the IDE or Continued Access arms of the ABC® and Trident® study. Data collection included revisions, complications, and noise. Out of 930 hips (848 patients) there were nine incidences of squeaking noise reported, no wear/osteolysis issues, and only two insert fractures (0.2%).

At ten years ceramic bearings show no wear, inconsequential lysis, minimal breakage, and occasion noise. Clinically, alumina ceramic bearings perform as well as the metal-on-polyethylene, with fewer revisions and less osteolysis, suggesting that they are a safe, viable option for younger, more active patients.


I. C. Clarke K. Kubo A. Lombardi E. McPherson A. Turnbull A. Gustafson D. Donaldson

Ceramic-on-ceramic alumina bearings (ALX) have demonstrated low wear with minimal biological consequences for almost four decades. An alumina-zirconia composite (BIOLOX-DELTATM) was introduced in 2000 as an alternative ceramic. This contains well-distributed zirconia grains that can undergo some surface phase transformations from tetragonal to monoclinic. We analyzed 5 cases revised at 1–7 years to compare to our simulator wear studies. For the retrieved DELTA bearings, two important questions were

how much tetragonal to monoclinic transformation was there in the zirconia phase and

how much did the articular surfaces roughen, either as a result of this transformation or from formation of stripe wear zones?

The retrieval cases were photographed and logged with respect to clinical and revision details. The DELTA balls varied from 22mm to 36mm diameters. These had been mated with liner inserts varying by UHMWPE, BIOLOX-FORTE and BIOLOX-DELTA materials. Bearing features were analyzed for roughness by white-light interferometry, for wear by SEM, for dimensions by CMM and for transfer layers by EDS technique. Surface transformations on DELTA retrievals were mapped by XRD. The four combinations of 36mm diameter BIOLOX-FORTE and BIOLOX-DELTA were studied in a hip simulator, which was run in ‘severe’ micro-separation test mode to 5 million cycles. Wear rates, wear stripes, bearing roughness and wear debris were compared to the retrieval data.

In two DELTA ball cases, there were conspicuous impingement signs, stripe wear and black metallic smears. It is to be noted that the metal transfer sites (EDS) appeared to be from the revision procedures. The retrieved balls run with alumina liners showed monoclinic phase peaking at 32% on the particular surface and internal bore. On the fracture surface of case 1, the monoclinic content had increased to 40%. Various surface roughness indices were assessed on the bearings. The polished articular surfaces averaged roughness (Sa) of the order 3 nm, representing extremely smooth surfaces. The main wear zone was only marginally rougher (5 nm). In contrast the stripe wear zones had roughness of the order 55–140 nm.

In the laboratory, the DELTA bearings provided a 3–6 fold wear reduction compared to FORTE controls. Roughness of stripes increased to maximum 113nm on controls. Roughness of wear stripes showed FORTE with the highest and DELTA with the lowest values. DELTA bearings also revealed much milder wear by SEM imaging. Phase transformations showed peaks at < 30% for both main wear zone and stripe wear sites. It is hypothesized that the concentration of monoclinic phase reached a certain level due to compression contraint imposed by the alumina matrix. With implant wear, additional tetragonal grains of zirconia are exposed and these will also transform to tetragonal. This consistency between laboratory and retrieval studies confirmed the stable nature of the bearings. The BIOLOX-DELTA combination provides optimal potential for a clinically relevant reduction in stripe wear.


TJ Blumenfeld DA Glaser WL Bargar RD Komistek GD Langston MR Mahfouz

Previous in vivo studies pertaining to THA performance have focused on the analysis of gait. Unfortunately, higher demand activities have not yet been analyzed. Therefore, the objective of the present study was to determine the in vivo kinematics for THA patients, using fluoroscopy, while they performed four higher demand activities.

The 3D in vivo kinematics of 10 THA patients were analyzed during the following activities: pivoting (PI), tying a shoe (SHOE), sitting down (SDOWN) and standing up (SUP) with and without the aid of handrails. Patients were matched for age, height, weight, body mass index, diagnosis and femoral head diameter to control for confounding variables possibly having influence on the hip performance and kinematics of the various activities.

The largest amount, incidence and variation of separation (femoral head sliding in the acetabular cup) were achieved during the PI with 1.5mm (SD 1.1) and 9 of 10 (90%) subjects experiencing separation. For the SHOE, SDOWN and SUP activities the average separation values were 1.1, 1.2 and 0.7mm, respectively. Femoral head separation was observed in 8 of 10 subjects (80%) during SHOE, in 9 (90%) during SDOWN, and in only one of 6 (60%) during SUP.

In this present study, subjects demonstrated hip separation during the high demand subjects, which could be a concern because these same activities are subjected to higher bearing surface forces. Also, the presence of hip separation leads to reduced contact area between the femoral head and the acetabular cup, possibly leading to higher contact stresses.


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K. Kindsfater D.A. Dennis J. Politi

Introduction: Although use of modular femoral components in revision hip arthroplasty is widely accepted, many still question the need for modular versatility in primary THA. The purpose of our study was to examine in a large cohort the percentage of hips in which femoral component version was changed to optimize stability or avoid prosthetic impingement of the THA construct. We hypothesized that the percentage of hips needing version change in routine primary THA would be low.

Methods: This prospective study analyzed 1000 consecutive primary THAs using a modular S-ROM (DePuy) stem performed by 3 surgeons at 3 institutions all via a posterior approach. Mean patient age at surgery was 57.5 years; 51.6% were male. The difference in version between the femoral sleeve placed anatomically and the femoral stem was recorded intra-operatively.

Results: Femoral component version was changed in 47.9% of hips. Logistic regression analysis showed no correlation between the likelihood of changing stem version and patient age (p=0.87), gender (p=0.23), diagnosis (p=0.54), or surgeon (p=0.27). 10 hips (1%) experienced early dislocation (within 3 months post-op). With the numbers available, there was a slight trend of lower dislocation rate in hips where stem version was changed (0.6%) versus those in which it was not (1.5%, p=0.16, chi squared).

Conclusion: The incidence of femoral version change in routine primary THA was much higher than expected. It was difficult to predict the need to alter version based on clinical variables including diagnosis. Thus, we conclude it may be advantageous to routinely use a stem that allows variable version as it is not possible to pre-operatively determine when changing version will be required. In addition, we surmise our low dislocation rate compared to historical controls of THA performed using a posterior approach was aided by the ability to adjust version in almost half of our patients.


C. Colwell N. Steklov S. Patil D. D’Lima

Total knee arthroplasty (TKA) provides relatively pain-free function for patients with end-stage arthritis. However, return to recreational and athletic activities is often restricted based on the potential for long-term wear and damage to the prosthetic components. Advice regarding safe and unsafe activities is typically based on the individual surgeon’s subjective bias. We measured knee forces in vivo during downhill skiing to develop a more scientific rationale for advice on post-TKA activities A TKA patient with the tibial tray instrumented to measure tibial forces was studied at two years postoperatively. Tibial forces were measured for the various phases of downhill skiing on slopes ranging in difficulty from green to black.

Walking on skis to get to the ski lift generated peak forces of 2.1 ± 0.20 xBW (times body weight), cruising on gentle slopes 1.5 ± 0.22 xBW, skating on a flat slope 3.9 ± 0.50 xBW, snowplowing 1.7 ± 0.20 xBW, and coming to a stop 3 ± 0.12 xBW. Carving on steeper slopes generated substantially higher forces: blue slopes (range 6° to 10°), 4.4 ± 0.18 xBW; black slopes (range 15° to 20°), 4.9 ± 0.57 xBW. These forces were compared to peak forces generated by the same patient during level walking: 2.6 ± 0.4 xBW, stationary biking 1.3 ± 0.7 xBW, stair climbing 3.1 ± 0.31 xBW, and jogging 4.3 ± 0.8 xBW.

The forces generated on the knee during recreational skiing vary with activity and level of difficulty. Snow-plowing and cruising on gentle slopes generated lower forces than level walking (comparable to stationary biking). Stopping and skating generated forces comparable to stair climbing. Carving on steeper slopes (blues and blacks) generated forces as high as those seen during jogging. This study provides quantitative results to assist the surgeon in advising the patient regarding postoperative exercise.


D.A. DENNIS D.R. HEEKIN J. MURPHY

INTRODUCTION: Many orthopaedic device companies now offer a high flexion (HF) choice within their knee Arthroplasty portfolios. Early published results are mixed between standard (STD) and HF knee devices despite claims of increased flexion with the HF offerings. The purpose of this randomized, controlled, simultaneous, bilateral study was to compare two coronally conforming rotating platform devices to determine if flexion differences were attributed to implant design.

METHODS: Ninety-three subjects underwent simultaneous bilateral TKA across 8 centers. The HF device was randomly assigned to one side and the contralateral leg received the STD device. Average age was 61 years, 99% were diagnosed with osteoarthritis, 66% were females, average BMI was 32 and range of motion was measured by subjective expectations versus satisfaction.

RESULTS: The HF design had statistically better single leg active flexion (SLAF) 12 months after surgery compared to the STD. Consistent with Gupta et. al, in a subgroup with pre-op flexion < 120 degrees in both knees, the HF device was statistically superior in passive flexion, ROM, and SLAF by between 1.8 and 4.5 degrees at 6 months, 12 months, and longitudinally over all postoperative intervals using raw degrees, improvement from pre-op, and adjusting for potentially confounding variables. 57% of subjects preferred their HF knee 6 months postoperatively, although there was no difference in preference at 12 months.

DISCUSSION: The simultaneous bilateral design of this study necessitates that subjects act as their own control eliminating most confounding variables. Gains in postoperative flexion, although small, were superior in the HF TKA group and were greater in those subjects with less than 120 degrees of preoperative flexion, suggesting the ideal candidate for a HF TKA is one with lesser preoperative flexion.


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Jonathan Garnio

Squeaking has become a more common problem following hard on hard bearings in total hip replacements. Although most squeaking is occasional and not concerning to either patient or health care practitioner, some reports of squeaking indicate high percentages (7% or higher) that can be constant and quite concerning. Much work has been done in this area, and although the exact mechanism is not yet understood, most of the data suggests a particular hip replacement system (metal alloy, taper design, cup design) significantly elevates to quantity and quality of the squeaking problem to concerning levels. Those specific details are described in depth along with future studies to improve our understanding in the nature of this acoustical phenomenon.


S. Nakamura M. Kobayashi H. Ito H. Yoshitomi R. Arai K. Nakamura T. Ueo T. Nakamura

In Far East, including Japan and the Middle East, daily activities are frequently carried out on the floor. Deep flexion of the knee joint is therefore very important in these societies. Some patients who underwent total knee arthroplasty (TKA) in these countries often perform deep flexion activity, such as squatting, cross-leg sitting and kneeling. However it is still unknown that deep flexion activity affects long term durability after TKA. The purpose of this study was to examine the correlation between deep flexion and long term durability.

Between December 1989 and May 1997, 507 total knee arthroplasties were carried out in 371 patients using the Bi-Surface Knee System (Japan Medical Material, Osaka, Japan) at two institutions and routine rehabilitation program continued for one to two months after TKA. One patient who underwent simultaneous bilateral TKA was excluded because of pulmonary embolism within one month. The other 505 knees (370 patients) were divided into two groups according to the range of flexion after our routine rehabilitation program; one group (Group A: 207 knees) consisted of more than 135 degrees flexion knees and the other group (Group B: 298 knees) consists of less than 135 degrees flexion knees. Patients whose follow-up period was less than 10 years were excluded from this clinical evaluation. Range of flexion was measured preoperatively, at the time after routine rehabilitation program, and at the latest follow-up. Knee function was evaluated on the basis of Knee Society knee score and functional score preoperatively and at the latest follow-up. Kaplan-Meier survivorship analysis was performed with revision for any operation as the end point.

In Group A, the mean preoperative range of flexion was 133.0±16.3 degrees, and at the time after routine rehabilitation program, this improved to 139.7±5.1 degrees. This angle maintained to 136.2±14.3 at the latest follow-up. In Group B, the mean preoperative range of flexion was 111.6±20.4 degrees, and at the time after routine rehabilitation program, this improved to 114.5±13.6 degrees. This angle maintained to 118.2±17.8 at the latest follow-up. The Knee Society knee score and functional score was improved from 43.0±16.9 points and 39.0±20.2 points preoperatively to 95.1±5.8 points and 51.8±21.2 points at the latest follow-up, respectively in Group A. The Knee Society knee score and functional score was improved from 37.1±16.7 points and 31.9±18.4 points preoperatively to 92.5±8.7 points and 53.1±26.1 points at the latest follow-up, respectively in Group B. Kaplan-Meier survivorship at 10-year was 95.5% in Group A and 96.2% in Group B with any operation as the end point. The survivorship between Group A and Group B was not statistically significant.

Good range of flexion was maintained and Knee society score was excellent after a long time follow-up for the patients who achieved deep flexion after TKA. Deep flexion was proved not to affect long term durability in this Bi-Surface Knee System.


J. Victor L. Labey P. Wong J. Bellemans

A comparative kinematic study was carried out on six cadaver limbs, comparing tibiofemoral kinematics in five different conditions: unloaded, under a constant 130 N ankle load with a variable quadriceps load, with and without a constant 50 N medial and lateral hamstrings load. Kinematics were described as translation of the projected centers of the medial (MFT) and lateral femoral condyles (LFT) in the horizontal plane of the tibia, and tibial axial rotation (TR) as a function of flexion angle. In passive conditions, the tibia rotated internally with increasing flexion, to an average of −16° (range −12/−20°, SD 3.0°). Between 0 – 40° flexion, the medial condyle translated forwards 4 mm (range 0.8/5.5 mm, SD 2.5 mm), followed by a gradual posterior translation, totaling −9 mm (range −5.8/−18.5 mm, SD 4.9 mm) between 40° – 140° flexion. The lateral femoral condyle translated posteriorly with increasing flexion completing −25 mm (range −22.6 – −28.2 mm, SD 2.5 mm). Dynamic, loaded measurements were carried out in a knee rig. Under a fixed ankle load of 130 N and variable quadriceps loading, tibial rotation was inverted, mean TR 4.7° (range −3.3°/11.8° SD 5.4°), MFT −0.5 mm (range = −4.3/2.4 mm, SD = 2.4 mm), LFT 3.3 mm (range = −3.6/10.6 mm, SD = 5.1 mm). As compared to the passive condition, all these excursions were significantly different: p=0.015, p=0.013, and p=0.011 for TR, MFT and LFT respectively. Adding medial and lateral hamstrings force of 50N each, reduced TR, MFT and LFT significantly as compared to the passive condition. In general, loading the knee with hamstrings and quadriceps reduces rotation and translation as compared to the passive condition. Lateral hamstring action is more influential on knee kinematics than medial hamstrings action.


S. Walker Gokce Yildirim Sally Arno

The treatment of osteoarthritis using artificial knee joints is expected to expand further over the next decade. Increasingly, patients expect quicker rehabilitation, improved performance, and high durability. However, economic limitations require a reduced cost for each procedure, as well as early intervention and even preventative measures. The major goal of implant design needs to be a restoration of normal knee mechanics, whether by maximum preservation of tissues, or by guiding surfaces which replicate their function. In this paper it is proposed that total knees should exhibit anatomic knee mechanics, namely medial stability – lateral mobility.

Many studies in the past have shown that the neutral path of motion of the anatomic knee, is that the medial side remains relatively immobile in the AP direction, which will impart a feeling of stability, while the lateral side shows posterior femoral displacement with flexion, to obtain a high range of flexion. There is considerable rotational laxity about this neutral path to accommodate a range of positions and activities. Recent studies carried out in our laboratory using an up-and-down crouching machine, and other test machines, have conformed this mechanical behaviour. To further elaborate, we tested eight young male subjects in a 7T MRI machine, where compressive and shear loads were applied. AP displacements occurred laterally but not medially. We attributed this behaviour to the medial meniscus and the tibial bearing geometry under weight-bearing conditions.

On the basis of these various studies, we developed a method for the design of Guided Motion knees, which would be implanted without the cruciates, and which would restore anatomic knee mechanics. The method started with the femoral component, where the medial side had features to provide a continuous radius anteriorly, and distally to 75 degrees flexion when a post-cam would contact. This feature would prevent paradoxical anterior femoral sliding in early flexion. Multiple femoral positions were then defined for accommodating anatomic motion, in particular limited AP motion on the medial side, but posterior displacement laterally. Tibial bearing surfaces were generated accordingly.

Tests were carried out on the crouching machine and on a Desktop TKR Test machine to compare the TKR motion with anatomic. Although not accurate in all respects, the Guided Motion designs were closer than models of standard TKR’s today. Such Guided Motion designs hold the promise for restoring anatomic knee mechanics and a normal feeling knee.


A. Fritsche C. Zietz S. Teufel W. Kolp I. Tokar C. Mauch W. Mittelmeier R. Bader

Sufficient primary stability of the acetabular cup is essential for stable osseous integration of the implant after total hip arthroplasty. By means of under-reaming the cavities press-fit cups gain their primary stability in the acetabular bone stock. These metal-backed cups are inserted intra-operatively using an impact hammer.

The aim of this experimental study was to obtain the forces exerted by the hammer both in-vivo and in-vitro as well as to determine the resulting primary stability of the cups in-vitro.

Two different artificial bone models were applied to simulate osteoporotic and sclerotic bone. Polymeth-acrylamid (PMI, ROHACELL 110 IG, Gaugler & Lutz, Germany) was used as an osteoporotic bone substitute, whereas a composite model made of a PMI-Block and a 4 mm thick (cortical) Polyvinyl chloride (PVC) layer (AIREX C70.200, Gaugler & Lutz, Germany) was deployed to simulate sclerotic bone. In all artificial bone blocks cavities were reamed for a press-fit cup (Trident PSL, Size 56mm, Stryker, USA) using the original surgical instrument. The impactor of the cup was equipped with a piezoelectric ring sensor (PCB Piezotronics, Germany). Using the standard surgical hammer (1.2kg) the acetabular cups were implanted into the bone substitute material by a male (95kg) and a female (75kg) surgeon. Subsequently, primary stability of the implant (n=5) was determined in a pull-out test setup using a universal testing machine (Z050, Ziwck/Roell, Germany).

For validation the impaction forces were recorded intra-operatively using the identical press-fit cup design.

An average impaction force of 4.5±0.6kN and 6.3±0.4kN using the PMI and the composite bone models respectively were achieved by the female surgeon in vitro.

7.4±1.5kN and 7.7±0.8kN respectively were obtained by the male surgeon who reached an average in-vivo impaction force of 7.5±1.6kN.

Using the PMI-model a pull-out force of 298±72N and 201±112N were determined for the female and male surgeons respectively. However, using the composite bone model approximately half the pull-out force was measured for the female surgeon (402±39N) compared to the male surgeon (869±208N).

Our results show that impact forces measured in-vitro correspond to the data recorded in-vivo. Using the osteoporotic bone model the pull-out test revealed that too high impaction forces affect the pull-out force negatively and hence the primary implant stability is reduced, whereas higher impact forces improve primary stability considerably in the sclerotic bone model. In conclusion, the amount of impaction force contributes to the quality of the obtained primary cup stability substantially and should be adjusted intra-operatively according to the bone quality of each individual patient.


M.T. Bah P.B. Nair M. Browne

Implant positioning is a critical factor in assuring the primary stability of cementless Total Hip Replacements (THRs). Although it is under the direct control of surgeons, finding the optimal implant position and achieving a perfect fit remain a challenge even with the advent of computer navigation. Placement of the femoral stem in an excessive ante/retroversion or varus/valgus orientation can be detrimental to the performance of THR. To determine the effect of such malalignment, finite element (FE) computer modelling is often used. However, this can be time consuming since FE meshes must be repeatedly generated and solved each time for a range of defined implant positions. In the present study, a mesh morphing technique is developed for the automatic generation of FE models of the implanted femur; in this way, many implant orientations can be investigated in a single analysis.

An average femur geometry generated from a CT scan population of 13 male and 8 female patients aged between 43 and 84 years was considered. The femur was virtually implanted with the Furlong HAC titanium alloy stem (JRI Ltd, Sheffield, UK) and placed in the medullary canal in a baseline neutral nominal position. The head of the femur was then removed and both femur and implant volumes were joined together to form a single piece that was exported into ANSYS11 ICEM CFD (ANSYS Inc., 2008) for meshing. To adequately replicate implant ante/retroversion, varus/valgus or anterior/posterior orientations, the rigid body displacement of the implant was controlled by three rotations with respect to a local coordinate system. One hundred different implant positions were analysed and the quality of the morphed meshes analysed for consistency.

To check the morphed meshes, corresponding models were generated individually by re-positioning the implant in the femur. Selected models were solved to predict the strain distribution in the bone and the boneimplant relative micromovements under joint and muscle loading. A good agreement was found for bone strains and implant micromotions between the morphed models and their individually run counterparts. In the postprocessing stage further metrics were analysed to corroborate the findings of the morphed and individually run models. These included: average and maximum strains in bone interface area and its entire volume, percentage of bone interface area and its volume strained up to and beyond 0.7%; implant average and maximum micromotions and finally percentages of implant area undergoing reported critical micromotions of 50 μm, 100 μm and 150 μm for bone in growth. Excellent correlation was observed in all cases.

In conclusion, the proposed technique allowed an automatic generation of FE meshes of the implanted femur as the implant position varies; the required computational resources were considerably reduced and the biomechanical response was evaluated. This model forms a good basis for the development of a tool for multiple statistical analyses of the effects of implant orientation in pre-clinical studies.


A.V. Lombardi K.R. Berend J.B. Adams

Lateral retinacular release (LRR) may be necessary to balance the patellofemoral articulation in primary total knee arthroplasty (TKA). However, lateral retinacular release may be associated with an increased risk of patellar necrosis, loosening, perioperative bleeding, and pain.

Additionally, the need for lateral retinacular release may herald a more significant problem with implant positioning, rotation, and balance. The purpose of this study is to report the lateral retinacular release rate with a “patella friendly” femoral TKA design, and to identify if a less invasive approach is associated with reduced need for lateral retinacular release.

A retrospective review of our database identified 4667 primary TKA performed by two surgeons between October 2002 and January 2009. Beginning in 2002, a less invasive approach has been used in over 95% of primary TKA. Also beginning in 2002, the authors began using a new TKA design with a more swept back patellofemoral articulation (Vanguard Complete Knee System; Biomet). During the first two years of the study, the authors also used the Maxim Complete Knee System (Biomet). We previously reported a lateral retinacular release rate associated with the Maxim of 22%. There were 555 Maxim and 4112 Vanguard TKA performed. Lateral retinacular release with Maxim TKA was 12.8% (71/555), significantly less than that previously reported for the same implant design using a standard approach. Lateral retinacular release for Vanguard TKA was 1.8% (72/4112), significantly less than that with the Maxim TKA using either a standard or less invasive approach (p< 0.005).

Implant design, surgical technique, and a less invasive exposure combine to significantly reduce the need for lateral retinacular release in primary TKA.


Y. Song N. J Giori H. Ito M. R. Safran

Cam type femoro-acetabular impingement is defined by a reduced femoral head-neck offset and by excessive bone at antero-lateral femoral head-neck junction.

Reconstruction of the femoral head-neck offset by removing the femoral bony prominence is a common treatment for cam type impingement. In many cases, the goal of this treatment is to make the antero-lateral head-neck offset symmetrical to the postero-lateral offset. However, guidelines for bony removal are not well established. The objective of this study is to examine if the antero-lateral and postero-lateral femoral offsets are symmetrical in normal healthy hips.

CT analyses of the anatomic geometry of the femoral head and neck were performed. Hip joints with any evidence of cartilage defects and impingement were excluded. Eight cadaveric hips (3 right and 5 left hips) were examined. The average age of the cadavers was 65.1±15.1 years. A peripheral QCT scanner was used which provided 0.2 x 0.2 x 2 mm resolution. To improve the resolution of the final result, each hip joint was scanned in three different scanning directions (sagittal, coronal, and axial scanning planes). A custom imaging fixture was built to position a joint sample in three different scanning planes and a custom irrigation system supplied saline to protect the sample from dehydration. A custom segmentation program was developed to delineate the bony contours of the femoral head and neck in a fully automated manner. The segmentation data from the three differenent imaging planes were merged and a 3D solid model of each hip joint was created. The prominence of the femoral head was determined by the distance of the 3D head from an ideal sphere fitted into the 3D model.

All the femoral heads were found to be asymmetric. Prominence of posteromedial femoral head averaged 0.105 mm more than the antero-medial femoral head.

The antero-lateral head-neck junction was also found to be more prominent than the postero-lateral head-neck junction by an average of 1.09 mm. Asymmetry in the femoral head and femoral head-neck junction was a general finding in normal hip joints. The conventional approach of symmetric reconstruction of femoral head-neck junction may result in unnecessary removal of bone at the antero-lateral head-neck junction and potentially increase the risk of femoral neck fracture.


C. M. Maguire T. M. Seyler R. H. Jinnah

Femoroacetabular impingement (FAI) has been identified as the cause of idiopathic osteoarthritis in young patients. FAI is the result of decreased femoral head/neck offset ratio due to bony deformities and causes hip pain and labral tears. Because the unique design and bone preserving nature of metal-onmetal hip resurfacing implants, it is extremely difficult to correct extensive bony deformities associated with FAI. Poor patient selection and lack of orrection/undercorrection of the underlying FAI deformity may lead to prosthetic impingement, extensive wear and metal ion release, component loosening, and subsequent implant failure. Hence, it is critical to define the patient population undergoing hip resurfacing. Because metal-on-metal hip resurfacing is performed more frequently in a younger population, we hypothesize that this patient population will have a larger proportion of femoroacetabular impingement than the general population and identification of this patient population is critical to the longevity of the implant.

A retrospective review of 153 hips undergoing metal-on-metal hip resurfacing was performed. 52 hips were excluded based on the exclusion criteria of inadequate preoperative films (6 subjects), existing hardware/history of trauma (11 subjects), or if the resurfacing was performed due to avascular necrosis secondary to trauma, steroids, etc (35 subjects). The remaining 101 hips (76 male, 25 female) had an average age of 51.8 years. Preoperative x-rays were utilized to assess impingement according to previously published methods. An acetabular index (AI) of x ≤ 0°, center edge angle (CE angle) of x > 39°, a Sharp angle of x < 33°, and a present cross-over sign were considered pathologic findings for pincer impingement. Pathologic findings for cam impingement included the triangular index (TI; pathologic with R=r+2mm) and an α angle greater than 83° in men or 57° in women. Subjects were categorized as having impingement if they had one or more pathologic finding for either cam or pincer impingement and as having mixed impingement if they had one pathologic finding for both cam and pincer measurements. Prevalence rates were compared to published data for the general population.

Fifty-five subjects had at least one pathologic finding for cam impingement (18, 7, and 30 subjects had pathologic measurements for α angle, TI, and both measurements, respectively); 24 subjects had at least one pathologic pincer measurement (4, 6, 14, and 4 pathologic measurements for AI, CE angle, cross-over sign, and Sharp angle, respectively; 3 subjects had multiple pincer findings) 13 subjects were classified as having mixed impingement (with α angle and cross-over sign as the most prevalent cam and pincer measurements). When compared to published data for the general population (M: 17%, F: 4%), we found a significantly larger proportion of cam impingement in both males (60.5%) and females (36%) in patients undergoing resurfacing at our institution (p< 0.001). There was also a significantly larger proportion of pincer impingement in our population (23.8%) than in the general population (10.7%) (p=0.01). There was no significant difference between our proportion of patients with mixed impingement (12.9%) and the general population (20.8%) (p=0.150).

The patient population for metal-on-metal hip resurfacing shows a greater prevalance of FAI than the general population. Because the femoral head/neck junction is preserved with hip resurfacing, patients undergoing this type of procedure might be at increased risk of impingement. Hence, it is important to assess the degree of FAI preoperatively. This will allow proper patient selection and careful planning of surgical correction of the underlying FAI deformity to increase implant longevity.


A.V. Lombardi M.D. Skeels K.R. Berend J.B. Adams

With increased use of alternative bearings, surgeons have moved from utilization of 22, 26, 28 and 32mm heads to larger head diameters in total hip arthroplasty (THA). Reported benefits of large heads are enhanced stability secondary to the increased range of motion prior to impingement and the increased jump distance required for subluxation from the acetabulum.

This study evaluates the use of large diameter heads in primary THA comparing the rate of dislocation to a published study from our practice as a historic control.

Between October of 2001 and October 2008, 2015 THA with large heads were performed in 1743 patients. Femoral head sizes ranged from 36 to 60mm, with articulations consisting of metal-on-poly, ceramic-on-poly, and metal-on-metal. Operative approach was 63% less invasive direct lateral, 10% anterior supine intermuscular, and 27% standard direct lateral. In 1999 (Mallory et al., Clin Orthop Relat Res) we reported a low incidence of 12 dislocations (0.8%) in 1518 primary THA done with smaller femoral heads via a standard direct lateral approach. In the current series with large heads, follow-up averaged 22 months. There has been one dislocation requiring revision (0.05%), representing a significant reduction from our earlier report (p=0.0003). Forty additional acetabular components have been revised (2.0%), with eight related to sepsis (0.4%), 23 aseptic loosening (1.1%), six metal sensitivity (0.2%), one pseudotumor (0.05%), one failure of ingrowth (0.05%), and one acute early migration (0.05%).

The use of larger diameter heads has significantly lowered our dislocation rate in primary THA with only one occurrence observed in 2015 cases, for a rate of 0.05% at two years average follow-up.


J.C. Finch L.G. Morawa R. Ramakrishnan

In patients with significant bone loss and a nonfunctioning extensor mechanism, the approach to revision is complicated. We describe a unique approach to solve this complex problem to help restore clinically satisfactory results. Our technique involves the use of a donor allograft that consists of proximal tibia along with the attached extensor mechanism (patellar tendon-patella-quadriceps tendon).

Five reconstructions utilizing bone allografts and extensor mechanisms were performed by two surgeons. Each has extensive surgical history on the affected knee and presented with gross instability, considerable bone loss, and significant extensor lag or total loss of extension. The implants used were press-fit stems with the tibial baseplate cemented into the allograft prior to implantation. In this series, either hinged or total stabilized prostheses were used.

The follow up ranged from 1 to 5 years. The only complication to date was reported in one patient who required irrigation and debridement with surgical wound closure after partial dehiscence. However the patency of the allograft was not disrupted.

All prostheses have been noted to be stable with no signs of loosening.

This procedure presented should be considered a salvage procedure for bone stock and extensor mechanism deficiency in revision total knee arthroplasty. The advantage to our allograft is the inherent stability of the proximal tibia with the tibial tubercle and associated extensor mechanism. For patients with this complex deficiency, there has been no effective method of treatment and we advocate the use of this procedure to restore function and relieve pain to an otherwise grossly unstable and functionally limited joint.


Takashi Itokawa Makoto Kondo Kazuhide Tomari Miyuki Sato Masashi Hirakawa Katsutoshi Hara Nobuhiro Kaku Y. Higuma T. Noguchi H. Tsumura

Introduction: Appropriate femoral component alignment is important for long-term survival of total knee arthroplasty (TKA). Valgus angle of femoral component is recommended as the angle between mechanical axis and anatomical axis of the femur. Intramedullary guide system is widely used for determining the valgus positioning of femoral component. Entry point of intramedullary guide is one of the key factors for determining valgus angle of femoral component. Some investigators have shown appropriate entry points of intramedullary guide, however, it is still unclear. In this study, appropriate entry point of intramedullary guide system was calculated using three-dimensional digital templating software “Athena” (Soft Cube, Osaka, Japan).

Method: Forty-one knees in 34 osteoarthritis patients except valgus deformity (30 females and 4 males, mean age 75.1 years) received TKA and were simulated using “Athena” from January 2009 to March 2009. All cases were grade III or IV in Kellgren-Lawrence index. Radiograph and CT scan image were used for determination of appropriate entry point of femur using “Athena”. The anatomical axis of femur was defined as a line connecting the midpoints of femoral AP and lateral diameter, at 60 mm and 110 mm proximal to the center of intercondylar notch. Two coordinate systems were configured as representation of entry points. One was at the center of intercondylar notch defined as the point of origin in axial view of CT image and the line parallel to the clinical epicondylar axis (cTEA) defined as X-axis. Another coordinate system was the same point of origin but parallel to the line between trochlear groove and the center of intercondylar notch (AP line) defined as Y-axis.

Result: In the coordinate system that defined the cTEA as the X-axis, the average of entry point was 0.3± 0.30 mm medial (range, −4.8~ 4.7mm) and 11.6 ± 0.52mm anterior (range, 3.1~ 16.5mm) to the center of intecondylar notch. In the other coordinate system that defined AP line as the Y-axis, the average of entry point was 2.6± 0.29 mm medial (range, −1.5~ 6.3mm) and 11.2±0.52 mm anterior (range, 2.8~ 16.0mm) to the center of intercondylar notch.

Discussion: In this study, the appropriate entry point of intramdullary guide was slightly medial and about 11mm anterior to the center of intercondylar notch on average. However, individual entry point varied considerably in distance. These data indicates that it is important to simulate the appropriate entry point of intramedullary guide in preoperative planning.


WL Walter A. Shimmin

Reasons for failure of hip resurfacing arthroplasty include femoral neck fracture, loosening, femoral head osteonecrosis, metal sensitivity or toxicity and component malpositioning.

Patient factors that influence the outcome include prior surgery, body mass index, age and gender, with female patients having two and a half times greater risk of revision by 5 years than males 14. In 2008, the Australian National Joint Replacement Registry (ANJRR) reported poorer results with small sizes, whereby component sizes 44mm or less have a five times greater risk of revision than those 55mm or greater 1. This finding is true for both males and females and after accounting for femoral head size, the effect of gender is eliminated.

We explore the relationship between component size and the factors that may influence the survivorship of this procedure, resulting in higher revision rates with smaller components.

These include femoral neck loading, edge loading, wear debris production and the effects of metal ions, cement penetration, component orientation, and femoral head vascularity. In particular the way the components are scaled from the large sizes down to the smaller sizes results in some marked changes in interactions between the implant and the patient.

Wall thickness of the acetabular and femoral component does not change between the large and small sizes in most devices. This results in a relative excessively thick component in the small sizes. This may cause more acetabular and femoral bone loss, increased risk of femoral neck notching and relative undersizing of the component where acetabular bone is a limiting factor. Stem thickness does not change throughout the size range in many of the devices leading to relatively more femoral bone loss and a greater stiffness mismatch between the femoral stem and the bone. Relatively stiffness between the femoral stem and the bone is up to six times greater in the small size compared to the large size in some designs.

The angle subtended by the articular surface (the articular arc) ranges from 170° down to as low as 144° in the small sizes of some devices. A smaller articular arc increases the risk of edge loading, especially if there is any acetabular component malpositioning. Acetabular inclination has been related to metal ion levels 5 and to the early development of pseudotumour6.

An acetabular component with a radiographic inclination of 45° will have an effective inclination anywhere from 50° to 64° depending on the type and size of the component. This corresponds to a centre-edge angle from 40° down to 26°. The effective anteversion is similarly influenced by design.

The result of a smaller articular arc is to reduce the size of the ‘safe window’ which is the target for orthopaedic surgeons.


Jean-Noel A. Argenson Sebastien Parratte Jean-Manuel Aubaniac

Improving the adaptation between the implant and the patient bone during total hip arthroplasty (THA) may improve the survival of the implant. This requires a perfect understanding of the tridimensional characteristics of the patient hip. The perfect evaluation of the tridimensional anatomy of the patient hip can be done pre-operatively using CT-scan and in case of important hip deformation, a custom implant can be used. When this solution is not available, modular necks may be a reliable alternative using standard x-rays and intraoperative adaptation. We aimed to evaluate:

The usefulness of modular neck to restore the anatomy of the hip and

the short-term clinical and radiological results of a consecutive series of THA using modular neck.

We prospectively included 209 hips treated in our institution with a modular neck total hip arthroplasty between January 2006 and December 2007. All patients underwent a standard xrays evaluation in the same center according to the same protocol. Pre-operatively, the frontal analysis of the hip geometry was performed and the optimal center of rotation, CCD angle, neck length and lever arm was analyzed to choose the optimal modular neck shape among 9 available shape. These 9 frontal shapes are available in standard, anteverted or retroverted shapes, leading to 27 potential neck combinations. The mean patient age was 68 years and the mean BMI 26 Kg/m2 All the procedures were performed supine using a Watson-Jones approach and the same anatomic stem. Intra-operatively the sagittal anatomy of the hip was analyzed and a standard, ante or retro modular necks were tested for the frontal shape defined pre-operatively.

According to the pre-operative frontal planning, nonstandard necks were required in 24 % of the cases to restore the anatomy of the hip. Intra-operatively, a sagittal correction using anteverted neck was required in 5% of the cases and retroverted necks in 18% of the cases.

Harris hip score improved from 56 to 95 points at last follow-up. No leg length discrepancy greater than 1 cm was observed. Restoration of the lever arm (mean 39.3 mm, range 30 to 49 mm) and of the neck length (55.2, range 43 to 68 mm) was adapted for 95% compared to the non operate opposite side. No loosening was observed.

According to our results modular neck combined are useful and reliable to restore optimal hip geometry and in this series 25% of the patient would have had imperfect extra-medullary hip geometry with a standard prosthesis. The good clinical and radiological short-term results should be confirmed at longer follow-up.


J.M.S. Lamvohee R. Mootanah P. Ingle J.K. Dowell K. Cheah

Cemented total hip replacements (THR) are widely used and are still recognized as the gold standard by which all other methods of hip replacements are compared. [1]. Long-term results of cemented total hip replacements show that the revision rate due to aseptic loosening could be as high as 75.4% [2]. Moreover, high stresses developed in the cement mantle of reconstructed hips can lead to premature failure of the constructs [3]. Surgical fixation techniques vary considerably [4]. The aim of this study was to investigate the performances of different surgical fixation techniques of hip implants for patients with different body mass indices, bone morphology and bone quality, using finite element (FE) methods.

Anatomically correct reconstructed hemi-pelves were created, using CT-Scan data of the Visible Human Data set, downloaded to Mimics V8.1 software, where poly-lines of cancellous and cortical bones were created, and exported to I-Deas 11.0 FE package, where the econstructed hemi-pelvis was simulated. Accurate 3D model of the hemi-pelvis was scaled up and down to create hemi-pelves of acetabular sizes of the following diameters: 46 mm, 52 mm, and 58 mm. Following sensitivity analyses, element sizes ranging from 1–3 mm were used. Material properties of the bones, implants and cement were taken from literature [57]. Bones of poor quality were simulated by a reduction in the elastic modulii of the cortical bone by 50%, the cancellous bone by 10 % and the subchondral bone by 50% [5]. The nodes at the sacro-iliac joint areas and the pubic support areas were fixed. A compressive force of 3 times body weight was simulated at the hip joint. The nodes between the cancellous and subchondral bones were merged. Contact elements were used at the subchondral bone and cement mantle interface and between the femoral head implant and acetabular component. Dynamic in vitro tests, simulating forces acting on a hip joint during a gait cycle, were carried out on reconstructed synthetic bones, positioned on an Instron 8874 hydraulic machine, to verify the FE models.

The volume of cement stressed at different levels in groups of 0–1 MPa, 1–2 MPa and up to 11 and above MPa were calculated. Results of FE analyses showed that

an increase in the body mass index from 20 to 30 generated an increase in the tensile stress level in the cement mantle;

lower tensile and shear stresses developed in thicker cement mantles. For a 46mm acetabular size, peak tensile stresses decreased from 10.32MPa to 8.14MPa and peak shear stresses decreased from 5.36MPa to 3.67MPa when cement mantle thickness increased from 1mm to 4mm.

A reduction in the bone quality would result in an increase of approximately 45% in the cement mantle stresses.

Results of in-vitro tests show that an increase in the cement mantle thickness improved fixation, corroborating with the FE results.

Performances of fixation techniques depend on the patient’s bone mass index, bone quality, bone morphology.


B. Grimm T. Boymans I.C. Heyligers

Introduction: In total hip arthroplasty (THA) an optimal fit and fill of the stem is essential for stable fixation. Thus femur morphology must be studied during pre-op planning (implant choice, sizing, positioning) or when a new stem is to be designed. Using plain AP x-ray analysis and the definition of a simple two-level parameter (canal flare index, CFI), Noble et al. identified an age related transition of the endosteal canal in AP view from a ‘champagne flute’ to a ‘stove pipe’. This reference data is 2D only, limited to the endosteal geometry and the elderly age range was defined as 60–90yrs so that the number of octogenerians > 80yrs was too low to analyze morphological features of this rapidly growing and critical THA patient population.

In this study the endosteal and periosteal femur morphology of subjects > 80yrs was studied using 3D CT analysis. It was the goal to

describe age related changes of the femur morphology in 3D,

to study the influence of gender

to investigate if the results may affect fit & fill of current stem designs.

Methods: High-resolution CT-scans (slice thickness 1mm) were made of 170 consenting volunteers (m/ f=101/69). The old group consisted of 119 subjects ≥80yrs (m/f=65/54, mean age: 84.1yrs [80–105]) and the young group of 51 subjects < 80yrs (m/f=36/15, mean age 67.8yrs [39–79]). After thresholding the bone boundaries in Mimics V12 (Materialise, B), the endos-teal and periosteal coordinates were analyzed for width, wall thickness, surface areas and various CFI’s relating dimensions at 20mm above LT and at a distal level (e.g. 60mm below LT, isthmus): Surface CFI (3D-CFI), frontal and lateral CFI based on the AP and ML projections (2D-CFI) and flaring in each of the four directions (1DCFI).

Results: The surface CFI was sign. lower in subjects ≥80yrs (5.08 ±1.23) than in subjects < 80yrs (6.61 ±1.72, p< 0.0001). This difference was sign. larger in females than in males (−32% vs. −17%), an observation valid with reference to any distal level. Equivalent age differences were found in both the frontal and lateral 2D-CFI as well as the medial, lateral and anterior 1D-CFI with changes in the anterior direction (−26.3%) being most dominant. In addition wall thickness was sign. reduced in the very elderly. E.g. at 20mm above LT, the medial wall measured 10.40mm at < 80yrs and 7.61 at ≥80yrs, a reduction of −27% (p< 0.001). In females (−35%) this difference was sign. larger (males: −23%, p< 0.001) even when corrected for height.

Discussion: The age driven transition of proximal femur morphology continues in the octogenarian population. This transition is not limited to two discrete levels in the AP plane as previously reported but it is a continuous 3D phenomenon with high directional asymmetry. In addition, this transition also affects the wall thickness and the periosteal shape. Furthermore a strong gender effect was identified with aging females showing increasingly and asymmetrically less flaring and thinner walls. An age and gender specific THA stem design seems necessary to fit the morphed femur. The asymmetric transition prohibits the effective use of current implant systems with proportionally scaled dimensions but favors a matrix sizing scheme with frontal and lateral dimensions changing independently.


T.M. Ecker C. Robbins G. van Flandern D. Patch S.D. Steppacher W. Kurtz B.E. Bierbaum S.B. Murphy

While alumina ceramic-ceramic THA has been performed in the US for more than 12 years, the phenomenon of frequent, clinically reproducible squeaking is relatively new. The current study investigates the influence of implant design on the incidence of squeaking.

We reviewed implant information on 1275 consecutive revision THAs performed from 10/2002 through 10/2007 to identify any patients who had complained of squeaking or grinding. We also identified, 2778 consecutive primary ceramicceramic THA. Of these, we reviewed the clinical records of 1,039 patients (37%) to date. Any patient complaint of squeaking or grinding at the time of an office visit or by phone interview was recorded. Hips were divided into group 1: flush mounted ceramic liner; group 2a: recessed ceramic liner mated with a stem made of TiAlV and using a 12/14 neck taper; and group 2b: recessed ceramic liner mated with a stem made of a beta titanium alloy comprised of 12% molybdenum, 6% Zirconium, and 2% Iron and using a neck taper smaller than a 12/14 taper.

Of the revision THAs, 5 hips (0.4%) were in patients who had complained of squeaking or grinding. All 5 hips had a recessed, metal-backed ceramic liner and evidence of metallosis. In primary THAs, Group 2b had statistically significantly (p=0.04) more squeaking (7.6%) than group 2a (3.2%) which had statistically significantly (p=0.002) more squeaking than group 1 (0.6%).

Squeaking following ceramic-ceramic THA is associated with use of a recessed metal-backed ceramic liner in combination with a femoral component made of a betatitanium alloy and using a relatively small head-neck taper. Since all revised hips in our study had metallosis, it is possible that metal debris is adversely affecting the bearing and that the elevated metal rim combined with a small head neck taper and the beta-titanium alloy contribute to this problem. Use of bearings with a flush-mounted ceramic liner mated with femoral components made of TiAlV and using a 12/14 taper appears to be prudent.


S.D. Stulberg T.C. Moen R. Ghate N. Salaz

Originally introduced in 1997, porous tantalum is an attractive alternative metal for orthopaedic implants because of its unique mechanical properties. Porous tantalum has been used in numerous types of orthopaedic implants, including acetabular cups in total hip arthroplasty. The early clinical results from porous tantalum acetabular cups have been promising. The purpose of this study was to evaluate the presence of bone ingrowth and the incidence of osteolytic lesions in the acetabular cup -at 10 year follow up – in patients who had a total hip arthroplasty with a monoblock porous tantalum acetabular cup.

50 consecutive patients underwent a total hip arthroplasty with a monoblock porous tantalum acetabular component. All patients had computed tomography at an average of 10 years of follow-up. The computed tomography scan used a standard, validated protocol to evaluate bony ingrowth in the cup and for the presence of osteolysis.

The computed tomographic scans showed evidence of extensive bony ingrowth, and no evidence of osteolysis.

This study reports the 10-year results of a monoblock porous tantalum acetabular cup. This is the first study to evaluate a porous tantalum acetabular cup with the use of computed tomography. These results show that a porous tantalum monoblock cup has excellent bony ingrowth and no evidence osteolysis at 10 year follow-up. These results suggest that porous tantalum is an attractive material for implantation in young, active patients.


S.C. Wollera K. Bertinc S.M. Stevensa K. Samuelson J. Hickman R. Hanseen R.S. Evans J.F. Lloyd P. Dechet C.G. Elliotta

Current orthopedic practice requires consideration of apparently contradictory recommendations regarding VTE prevention among THR/TKR patients. American College of Chest Physicians (ACCP) 8th Clinical Practice Guidelines for the Prevention of Venous Thromboembolism recommend against aspirin for VTE prophylaxis in any patient1. The American Academy of Orthopedic Surgeons (AAOS) Guideline recommends pulmonary embolism risk stratification, then implementation of one of many possible courses including the use of aspirin2.

We conducted a prospective observational study among consecutive patients presenting for total hip or knee arthroplasty. Pre-operative PE risk stratification was performed at the discretion of the surgeon. Patients identified as usual risk for PE received aspirin. Patients considered being at elevated risk for PE received warfarin. This observational study protocol called for one year of data collection. At approximately 8 months 656 patients were enrolled, and the surgeon principally implementing PE risk stratification and administration of aspirin chose to stop enrolling patients due to a high incidence of pulmonary emboli. One hundred fifty five patients received thromboprophylaxis with aspirin 600 mg PR in the PACU, then 325 mg BID for one month (reduced to 81 mg daily if GI symptoms were present). The remaining 501 patients received an ACCP-based warfarin protocol managed by a pharmacist anticoagulation management service.

Our hypothesis is the null hypothesis; that an AAOS-based approach to hromboembolism prevention is not inferior to an ACCP-based approach. The a priori primary endpoints of the AVP Study are clinically overt VTE, DVT, PE, major bleeding, and death. All patients will receive a 90 day follow-up questionnaire in person or by telephone. Additionally, the electronic medical record of Intermountain Healthcare will be interrogated for ICD-9 codes germane to the outcomes of interest.

Ninety day follow-up has been completed for approximately 140 patients. The dataset will be locked upon completion of the 90 day follow-up among those patients who last received PE risk stratification and aspirin therapy (data lock early June, 2009). We anticipate preliminary data available for report by July, 2009.


J.J. Wu Q.Q. Wang I. Khan

Orthopaedic grade ultra-high molecular weight polyethylene (UHMWPE) remains the preferred material for one of the bearing surfaces in total joint prostheses because of its high wear resistance and proven biocompatibility. Since the 1970s, UHMWPE has served as the only widely used bearing material for articulation with metallic components in total knee arthroplasty (TKA). However, polyethylene-related total knee failures have limited the lifetime of total knee joint replacements. The present study is focused on improving material integrity and reducing the probability of material failure. The hypothesis examined here is that there is a correlation between material failure of UHMWPE knee-joint components and the precise time-temperature history employed during fabrication, due to their strong effect on interparticle cohesion. The presence of fusion defects due to incomplete consolidation and incomplete polymer self-diffusion has been implicated in the failure of UHMWPE joints [1, 2]. Computer-aided methodology used in this study allowed quantitative prediction and optimisation of the extent of interparticle cohesion to ensure that inter-particle boundaries are of high integrity during moulding [3]. The current study has investigated the correlation between inter-particle cohesion governed by reputation theory and wear performance.

We have investigated the wear performance of direct compression moulded UHMWPE plates with different degree of inter-particle diffusion. Direct compression moulding was used in the present study because of its uniformly excellent surface finish which is better than machined surfaces. UHMWPE plates (44×24×3mm) were direct compression moulded using GUR1050 powder (Ticona). Various moulding temperature (e.g. 145°C, 150°C, 175°C) and dwell time (e.g. 15mins and 30mins) were investigated.

The wear tests were carried out at 37°C using a Durham four-station multidirectional pin-onplate machine, which generates both reciprocating and rotating motions simultaneously. The material combination of the flat-ended metallic indentors loaded against UHMWPE plates was constructed to mimic conformal contact conditions in knee prostheses. The articulating surfaces were lubricated using 25% diluted bovine serum. Meanwhile the experimental method was validated by evaluating the wear generation under the conventional configuration (i.e. UHMWPE pins on metal plates); results were comparable with the data in the literature [4].

For the direct compression moulded UHMWPE plates, experimental wear factors were determined and found to correlate well with numerically calculated degree of inter-particle diffusion. Increasing moulding temperature and dwell time decreased the wear factors and increased inter-particle diffusion. Surface structures were characterised before and after every 0.5 million cycles. The observed surface features on UHMWPE plates in ESEM and optical microscopy is very similar to those in retrieved knee prostheses [5] and those found in our own recent work with knee wear simulator testing.


M Odumenya M L Costa S J Krikler N Parson J Achten

Purpose of Study: To identify the functional outcome, quality of life and prosthesis survivorship in patients who have undergone the Avon patellofemoral arthroplasty at an independent centre.

Method and Results: Sixty-three patellofemoral arthroplasty (PFA) procedures were undertaken on 44 patients between May 1998 to May 2007. The primary and secondary outcome measures were knee function and quality of life, respectively. These outcomes were determined using the Oxford Knee Score (OKS) and EQ-5D and visual analogue score. Out of the forty-four patients 6 were deceased and 6 were lost to follow-up.

Therefore, thirty-two patients (50 PFAs) were included; nine males and 23 females.

Seventeen patients had bilateral PFA. The mean age of the patients was 65.8 years (SD 9.2). Follow-up averaged at 5.34years (range 2.1–10.2years) (SD2.64). The Oxford Knee Scores in this population showed a bimodal distribution. One group centred around 35 and the other around 60. The median Oxford knee score was 42.5 (IQR 34.25 to 54.25). Two sample t-test analysis of the population, divided as those above and below an OKS of 42, showed that follow-up time and age, did not differ between the groups (p=0.325, p=0.255 respectively). The quality of life outcome scores were significantly lower for bilateral compared to unilateral patients, with median scores of 50 and 72.5 respectively (p=0.03829). The cumulative survival at 5years for those with minimum 5 year follow-up (32 out of 50 PFA) was 100%. Three knees in total were revised. One patient developed bilateral tibiofemoral osteoarthritis, requiring revision to total knee replacement (TKA) at seven and 10 years. Another had persistent anterior knee pain and was converted to a TKA.

Conclusion: The Avon patellofemoral arthroplasty provides good functional outcome. The survivorship rate is promising although longer follow-up is required. Prudent patient selection is needed avoid high rates of revision to TKA.


S. Takai N. Shimazaki N. Nakachi H. Mitsuyama Y. Konaga T. Matsushita N. Yoshino

Purpose: The effect of patellar position on soft tissue balancing in total knee arthroplasty (TKA) is under debate. We developed the digital tensor system to measure the load (N) and the distance (mm) of extension and flexion gaps in medial and lateral compartment separately with setting of femoral component trial. The gap load and distance in extension and flexion position of posterior stabilized (PS) and cruciate retaining (CR) TKA in both patella everted and reset position were measured.

Materials and Methods: Thirty-four patients who underwent primary TKA for medial type osteoarthritis using medial parapatellar approach were included. The load was measured at the gap distance, which is equal to the sum of implants including polyethylene insert.

Results: In extension, there was no significant difference between the load in patella everted and reset position in both PS-TKA and CR.-TKA. In flexion, there was a significant decrease of the load, which is comparable to the increase of gap distance of approximately 2mm, by resetting the patella from eversion in PS-TKA.

There was, however, no significant difference in CR-TKA by resetting the patella.

There was no significant difference in the ratio of medial/lateral load in both PSTKA and CR.-TKA.

Conclusion & Significance: Soft tissue balancing of PS-TKA with medial parapatellar approach should be performed after resetting the patella.


M.A. Baldwin C. Clary L.P. Maletsky P.J. Rullkoetter

Design phase evaluation of potential implant designs requires verified computational and experimental models. Computational models are important where parametric evaluation of geometric features experimentally is both cost and time-prohibitive due to the need to manufacture complex parts, and provide information not easily measured experimentally, such as internal stresses/strains in the implant or bone.

However, before implementation into the design process, a thorough verification/validation is required. In this study, a finite element model of the Kansas knee simulator (KKS) was developed and a systematic verification of predicted joint kinematics was performed by comparison with experimental measurements, including evaluating the patellofemoral joint first in isolation, followed by whole joint kinematic comparisons.

Four unmatched, healthy cadaver knees (average age 63 yrs) were mounted in the KKS to reproduce a simulated gait and deep knee bend activity in their natural and implanted states. Finite element models of the KKS assembly and the four cadaver specimens in their natural and implanted states were created. Isolated patellofem-oral kinematics were initially verified during simulated deep knee bend. Average RMS differences between predicted and experimental natural patellar kinematics were less than 3.1° and 1.7 mm for rotations and translations, respectively, while differences in implanted kinematics were less than 2.1° and 1.6 mm between 10 and 110° femoral flexion. Similar agreement was found with the subsequent whole joint simulations.

Deep knee bend tibiofemoral internal-external (IE) and varus-valgus (VV) rotations had average RMS differences from experimental measurements of 1.5 ± 0.4° and 0.9 ± 0.5°, respectively. Anterior-posterior (AP), inferior-superior (IS) and medial-lateral translations matched within 1.8 ±0.8 mm, 1.2 ±0.7 mm, and 0.6 ±0.1 mm, respectively.

The experimental and verified computational tools can be used in harmony for pre-clinical assessment of implant designs; the computational model allows rapid screening of implant geometry or alignment issues and provides additional insight into joint mechanics such as implant stresses or bone strains, while the experimental simulator can subsequently be utilized to assess in cadavera only the most promising designs or features identified.


J H Lonner T John M A Conditt

Bicompartmental arthritis involving the medial and patellofemoral compartments of the knee is a common pattern that has often been treated with total knee arthroplasty.

However, the success of unicompartmental and patellofemoral arthroplasty for unicompartmental arthritis, as well as an interest in bone and ligament conservation for earlier stages of arthritis, has led to an interest in bicompartmental arthroplasty. The purpose of this study is to review the clinical, functional, and radiographic results of modular bicompartmental arthroplasty.

Twelve consecutive modular bicompartmental arthroplasties, using separate contemporary unicompartmental tibiofemoral and patellofemoral prostheses, were performed by the senior author. Clinical and functional data including range of motion (ROM), WOMAC and Knee Society (KS) scores were collected pre-operatively and post-operatively at 6 weeks, 12 weeks and annually. Radiographs were taken preoperatively and at the 6 week and annual postoperative visits. The average patient age at the time of surgery was 63 (range, 47 to 72); seven patients were women.

At most recent follow-up, the mean knee ROM improved from 100 degrees of flexion pre-operatively (range, 90 to 110) to a mean of 126 degrees of flexion (range, 115 to 130) (p < 0.0001). Improvements in WOMAC scores were statistically significant (p = 0.02). Statistically significant improvements in Knee Society scores were also observed (p = 0.03). No radiographs showed evidence of loosening, polyethylene wear or progressive lateral compartment degenerative arthritis. There were no complications in the peri-operative period.

Modular bicompartmental arthroplasty is an effective method for treating arthritis of the knee restricted to the medial and patellofemoral compartments. Early results using contemporary prostheses are encouraging and should prompt further mid-and long-term study.


Sung-Do Cho Yoon-Seok Youm Chang-Yun Jung Chang-Ho Hwang

The purpose of this double-blinded prospective study was to evaluate the effectiveness of electromyography (EMG)-guided preoperative femoral nerve block (FNB) for postoperative analgesia in total knee arthroplasty (TKA).

Forty knees of primary TKA by one surgeon were included in our study. One doctor performed a single injection FNB with an EMG guide in EMG group (23 knees) and with a blind maneuver in control group (17 knees). The same 10ml of 0.375% ropivacaine was injected in both groups. Same postoperative rehabilitation protocol was applied to all patients. Continuous passive motion was started at postoperative 1st day and weight bearing was started as soon as possible.

Intravenous patient-controlled analgesics which contained 30mg of morphine were used until postoperative 72 hours and no additional intravenous, intramuscular or oral analgesics were used. Pain was evaluated by Visual Analogue Scale (VAS) and Postoperative Pain Score (PPS) at postoperative 4, 24, 48 and 72 hours. The amount of opioid consumption and complication were compared between two groups. VAS score was 6.8 in EMG group and 8.0 in control group at postoperative 4 hours, 6.2 and 7.1 at postoperative 24 hours, 5.3 and 5.9 at postoperative 48 hours, and 4.6 and 5.7 at postoperative 72 hours, respectively. PPS was 2.2 in EMG group and 2.2 in control group at postoperative 4 hours, 2.1 and 2.1 at postoperative 24 hours, 1.6 and 1.7 at postoperative 48 hours, and 1.4 and 1.6 at postoperative 72 hours, respectively. The amount of opioid consumption was 6.0mg in EMG group and 7.2mg in control group during postoperative 24 hours, 2.7mg and 3.2mg during postoperative 24–48 hours, and 1.7mg and 3.2mg during postoperative 48–72 hours, respectively. There was no complication in either group.

Pain tended to decrease more in EMG group than control group, especially VAS at postoperative 4, 24 and 72 hours (p< 0.05). The demand of opioid was significantly smaller in EMG group during postoperative 24 hours and 48–72 hours (p< 0.05). EMG-guided single FNB before TKA allowed better postoperative pain relief and reduced the demand of pain killer.


David J. Covall Bernard Stulberg Jay Maybrey

Introduction: The Posterior Cruciate Referencing Technique (PCRT) for total knee arthroplasty (TKA) uses innovative instrumentation and tibial inserts with varying posterior slopes, and is designed to maximize motion and stability in cruciate-retaining knees, while preserving bone and ligament integrity. This study evaluated early clinical results for this technique.

Methods: An IRB-approved, retrospective, single-site, single-surgeon study was conducted in 2009. 50 patients were put into two groups: Group 1 included patients undergoing CR TKA using standard technique and implants and Group 2 included patients undergoing CR TKA using PCRT. Demographics, surgical time, length of stay (LOS), range of motion, and Oxford Knee Scores (OKS) were collected.

Results: Data sets were complete on 41 patients. Follow-up averaged 14 months for Group 1 and nine months for group 2. Both groups had a mean age of 66.4, were 51% female, and had an average BMI of 30.6. LOS was 1.25 days for Group 1 and 1 day for Group2 (p=0.011). Surgical time was 48 minutes for Group 1 and 46 minutes for Group 2 (p=0.184). Average flexion was 118° for Group 1 and 123° for Group 2 (p=0.073). OK S were 92–94% good and excellent with a mean of 20.4 for both groups.

Conclusions: The learning curve for PCRT and the associated instrumentation and implants did not adversely affect clinical results. Instead, the data indicated a small savings in surgical time and a moderate, but not statistically significant, increase in flexion. LOS, however, was significantly shortened. PCRT may allow for better PCL function while preserving bone and reducing surgical manipulation, and with tibial inserts of varying posterior slopes may improve flexion, stability, and function in CR TKA. Further study is warranted.


AS Ranawat TW Koob JH Koenig HJ Cooper LF Foo HG Potter CS Ranawat

Introduction: Computer-based wear analysis is currently the most accurate method for determining the in vivo wear rates of polyethylene liners during total hip arthroplasty. MRI of a total hip is emerging as the best method for determining the intra-articular volume of particulate debris. The purpose of this study is to determine if there is a correlation between polyethylene wear and the development of particle load in patients with highly crosslinked (HXLP) liners.

Materials and Methods: 20 well-functioning total hips (7 metal heads against HXLP liners and 13 ceramic heads against HXLP liners) in 18 young active individuals were analyzed using the following criteria: femoral head penetration of the liner was measured by Roman (ROntgen Monographic ANalysis) software and particulate load was calculated by MRI criteria as described by Potter et al. Clinical and radiographic analyses were performed using HSS, WOMAC, and criteria defined by DeLee, Charnley, and Engh. The average age of the patients was 57 (Range 45–67) and average follow-up was 1.6 y (range 1.0 – 3.0 y).

Results: All implants appeared well osteointegrated with no radiographic evidence of osteolysis. All patients had well-functioning total hips with a greater than one mile daily walking tolerance. A trend towards correlation was observed between increased polyethylene wear and increased particulate volumes. Average HXLP wear was 0.03 mm (range −0.19 to 0.27 mm) and average particle volume was 841 (range 6951 to 0). One patient in particular recorded 0.27 mm of polyethylene wear, mild particle disease and a particle disease volume of 3321 at 1.6 years follow-up. However, statistical significance could not be achieved with these data points.

Conclusions: There appears to be a relationship between polyethylene wear as measured by computer-based systems and particulate volume as measured by MRI. Limitations of the current methodology include the inability of computer-based systems to detect precise levels of minimal wear with HXLP liners, and the highly sensitive MRI images which may be detecting more than just wear debris.


Bin SHEN Jing YANG Liao WANG Zong-ke ZHOU Peng-de KANG Fu-xing PEI

Objective: Considering the high incidence and misdiag-nostic rate of developmental dysplasia of hip (DDH) in China, some patients suffer from severe pain in the hip at early age, and a total hip arthroplasty would be necessary. To our knowledge, the intermediate-term(equal to or more than five years) results of total hip arthroplasty (THA) in patients with osteoarthritis secondary to developmental dysplasia of the hip has not been studied in China previously. This study evaluated more than five-year clinical and radiographic outcomes associated with total hip arthroplasty (THA) in a consecutive series of patients with osteoarthritis secondary to developmental dysplasia of the hip.

Methods: From February 2000 to July 2002, 55 patients (69 hips) underwent THA in our hospital were involved in this study. Clinical outcomes were evaluated according to Harris evaluate score. Components migration, periprosthetic bone changes, the polyethylene wear rate were measured radiologically. Kaplan-Meier analysis was performed to evaluate the survival of the acetabular and femoral component. End point was obvious radiological loosening or revision either or both of the acetabular and femoral component for any reason.

Results: Forty-five patients (57 hips) were followed up at least 5 years. The average preoperative Harris hip score was (46.19±18.01) points, which improved to (91.78±3.52) points at final follow-up. There were 48 excellent hips (84.21%), 7 good hips (12.28%), 2 fair hips (3.51%) and no poor hip. There is no significant difference of Harris score between the dysplasia group, the low dislocation group and the high dislocation group (P> 0.05, ANOVA). The mean polyethylene liner wear rate was (0.27±0.14)mm/year. According to the statistical relevant analysis, the wear rate of the polyethylene liner had relationship with the age(r=−0.288, P=0.040), the abnormal abduction angle of the acetabular cup (r=0.317, P=0.023)and the osteolysis rate (r=0.573, P=0.026), while had no significant relationship with the thickness of the polyethylene liner (P=0.326), gender(P=0.097), DDH classification(P=0.958) and the Harris score(P=0.598). There are 5 pelvic osteolysis and 8 proximal femoral osteolysis. Using loosening or revision as the end point for failure, the survival rate of both components was 1.0 (95% confidence interval, 0.98–1.00).

Conclusions: In conclusion, improved surgical technique and design in the components provided favorable mid-term results in Chinese patients with osteoarthritis secondary to developmental dysplasia of the hip. Bulk autogenous or allografting is not needed if more than 70% of the acetabular component is covered by host bone. Although the Asia life style includes more squatting and cross-legged, the results of this series in Chinese population are comparable to the satisfactory results of other reported DDH series whose patients are mainly western people. The mid-term results of THA are equivalent in the group of patients with dysplasia, low dislocation, and high dislocation types both in ace-tabular and femoral components. However, the authors continue to be anxious about the high rate of liner wear and osteolysis, which deserve the necessary long-term follow-up.


Y-H Kim J-S Kim W-S Huh K-H Lee

Although total knee arthroplasty (TKA) has been a reliable procedure providing durable pain relief, polyethylene (PE) wear remains a major limitation of the long-term success of TKA. One potential method of lowering PE wear in TKA is to use oxidized zirconium (OxZr)-bearing surface. Although wear simulating testing of an OxZr counter surface of femoral component produced less PE wear and fewer particles than did cobalt-chrome (Co-Cr) counter surface of femoral component [1–4], this finding has not been demonstrated in vivo to our knowledge.

We measured in vivo PE wear by isolating and analyzing PE wear particles in synovial fluid from wellfunctioning TKA [5]. The purpose of the current study was to determine the size, shape, and amount of PE wear particles isolated from synovial fluid of patients who underwent a bilateral simultaneous TKA prosthesis, but different materials of femoral components.

We performed a bilateral simultaneous TKA in 100 patients (200 knees) who received an OxZr femoral component in one knee and a Co-Cr femoral component in the other. Mean age was 55.6 (44–60) years. Synovial fluid was obtained from 28 patients (56 knees) who had undergone a simultaneous bilateral TKA under completely sterile conditions at one or two years after the operation. Randomization to an OxZr or Co-Cr femoral component was accomplished with use of a sealed study number envelope, which was opened in the operating room before the skin incision had been made. After the opening the randomization envelope, the first knee received prosthesis indicated by the envelope (OxZr or Co-Cr component) and the contralateral (second TKA) knee received the other prosthesis (OxZr or Co-Cr component).

All operations were performed by one surgeon using the same design of total knee prosthesis: Genesis II (Smith and Nephew, Memphis, Tennessee). Only the material of the femoral component differed between two groups. The preoperative diagnosis was osteoarthritis in all patients. Preoperative and post operative KS and HSS knee scores, KS functional scores and UCLA activity scores were evaluated.

The amount of polyethylene wear particles in the aspirated synovial fluid sample was analyzed by thermogravimetic analysis (TGA) using a TGA instrument (TGA/SDTA 84le model, Mettler Toledo CO., Greifensee, Switzerland). The weight of the sample solution was measured before and after removing the organic content by heating the sample solution. The sample solution was casted onto petri dishes. The petri dish was covered and kept in a dry oven at 60°C for 2 days. While the sample solution was kept in a dry oven for 2 days, a small hole was made on the cover of the petri dish to allow water to evaporate slowly for 2 days. After this procedure, the cover of petri dish was removed and TGA sample was dried at 60°C for another 2 days. After the sample was completely dried out, the dried sample was measured using analytical balance.

TGA was used to determine the weight change profiles of polyethylene subject to heating under a nitrogen atmosphere. The nitrogen flow rate was kept constant at 50mL per minute. TGA data were taken at heating rate as 5°C per minute in the temperature range of 20° to 1000°C. The weight loss data were recorded as a function of time and temperature using special software in computer. When the temperature reached to the point of decomposition of the sample, the sample started to lose weight. By calculating the weight of the sample around the temperature which led to start to decomposition, real amount of polyethylene in the sample was measured. The size and shape of PE particles were examined using scanning electron microscopy (JSH-6360A model, Jeol Co., Tokyo, Japan). The samples were coated using a platinum sputtering machine for 20 sec.

ANOVA, nonparametric chi square test, nonpaired t-test and Mann-Whitney U-test were used for statistical analyses. Differences of P< 0.05 were considered statistically significant.

Mean preoperative KS (27.5 vs 27.2 points) scores, HSS (51.1 vs 51.2 points) knee scores, KS functional scores (55.4 vs 55.4 points) and UCLA activity scores (2.8 vs 2.8 point) were not significantly different between two groups. Mean postoperative KS (93 vs 92 points), HSS knee scores (90 vs 89 points), KS functional scores (78 vs 78 points), and UCLA activity scores (7.8 vs 7.8) were not significantly different. Mean weight of the polyethylene particles was 0.0219 g (SD, 0.0058) in the Co-Cr femoral component groups and it was 0.0214 g (SD, 0.005) in the OxZr group. This difference was not significant (P=0.711139, paired t-test). The size of particles was not different between the two groups. Also, shape of particles was not different between the two groups.

Under the condition and the duration of this study in this specific group of patients, TKA with OxZr or Co-CR femoral knee component had excellent clinical and radiographic outcomes with no osteolysis. While the wear simulator test in vitro demonstrated significant decrease in PE particles in the knees with an OxZr femoral component, our study in vivo revealed that total particle weight, size, and shape of PE wear particles were similar in the knees with an OxZr femoral component and in those with a Co-Cr femoral component.


William G Ward Joshua Cooper

The presence of an unremovable cemented tibial nail presents a unique challenge for limb salvage reconstructions utilizing a rotating hinge knee. All manufacturers’ designs except Link America incorporate a vertically-oriented rotational channel in the proximal tibia to provide the housing for a rotational axis stem. Such channel placement may be impossible in patients with pre-existing tibial hardware that obliterates the proximal tibial intramedullary canal. The Link America design utilizes a superiorly-projecting rotational stem that articulates with a housing located on the rotational yoke component; however it requires an intramedullary tibial stem for component stabilization. Thus all currently available rotating hinge knees require placement of a stem or a stem equivalent into the tibial intramedullary canal.

We describe a limb salvage case employing a Link America rotating hinge knee with a tibial component incorporating a custom hollow stem in a patient with an unremovable centralized, straight, cemented tibial nail. This reconstruction was required following an intra-articular fracture of a successfully incorporated massive proximal tibial osteoarticular allograft. The allograft had been implanted seven years previously following resection of a proximal tibia osteosarcoma.

This custom device allowed a relatively simple limb salvage reconstruction with good results and only a two day hospital stay.

This custom hollow-stemmed device allowed limb salvage in a situation that otherwise would have required either an amputation or resection of a healed tibial allograft that had successfully incorporated, replacing approximately 50% of the length of the tibia shaft. While rarely required, such an implant can allow a relatively simple and straight-forward functional salvage of an extremity in those patients whose only other choices for limb salvage include much more extensive bone resections and complex reconstructions. The potential for subsequent articular level failure should be considered whenever utilizing an osteoarticular allograft. A cemented, retrograde inserted, intramedullary nail can provide reliable internal fixation of such an allograft. If such fixation is selected, a straight intramedullary nail (as in this case) should be utilized, so that the intramedullary device is centered in the proximal tibia. This will allow for future revision to a total knee with a hollow stemmed tibial component should the need arise.


A. Kinbrum A. Unsworth

Particulate debris created during a fiber-filled PEEK material (MOTISTM) rubbing on a ceramic femoral head in a hip wear simulation study was characterized. The particles were cleaved from the protein lubricant with a double enzymatic protocol and then sized using two different techniques. The sizes obtained were verified using an AFM imaging technique.

Many metal-on-UHMWPE joints ultimately fail due to late aseptic loosening. This occurs due to the particulate debris built up in the periprosthetic area. The body’s natural immunological response leads to bone resorption, the prosthesis becomes loose and severe pain can then necessitate revision. It is therefore important to characterize the wear particles of novel materials in order to understand their biological impact.

Particles were generated in a Durham hip wear simulator from a MOTISTM acetabular cup articulating against a ceramic femoral head for 25 million cycles1. The samples were generated in 500 ml of bovine serum lubricant (17 g/l protein) and a 10 ml sample of this lubricant was analyzed.

A double enzymatic protein cleavage protocol was used as it was shown to be the least harmful to the particles.

A bi-modal distribution of sizes was seen with a large number of particles of 100 nm and a large number at the two micron size range. AFM results verified the size of the particle distribution and also showed that the smaller particles were round to oval and the larger particles were long and thin. No carbon fibers were evident in the AFM images. Although the wear rate over the 25 million cycles1 remained low and linear, the average particle size tended to increase over the 25 million cycles whilst the volume of the particles decreases over the period.

Howling2 studied particle debris from a pin-on-plate carbon fiber reinforce PEEK against ceramic test using a 6M KOH protocol and resin embedded TEM analysis.

This method only allowed around 100 particles to be imaged at a time, no size distribution was given. Ctyotoxicity was also tested using U937 monocytic cells indicating that MOTISTM has no cytotoxic effects such as necrosis.


D.A. Dennis R.H. Kim D.R. Johnson B.D. Springer T.K Fehring P.J. Rullkoetter P.J Laz M.A. Baldwin

Introduction: Patellar crepitus (PC) has been reported in 13% of cruciatesubstituting total knee arthroplasty (TKA) patients resulting from synovial tissue impingement within the femoral component intercondylar box (IB). Patient factors, component design, and technical errors have been implicated in PC. We compared primary TKA patients with PC requiring surgery against matched controls to identify significant variables.

Methods: The databases of 2 institutions were reviewed to identify patients requiring surgery for PC. A control group matched for age, sex, and BMI was identified.

Patient charts and radiographs were reviewed. Statistical analysis was performed.

Significant variables associated with patient anatomy, implant size and alignment were subsequently investigated in a computational model to evaluate tendofemoral contact.

Results: Between 2002 and 2008, over 4000 primary TKAs were performed using the Press Fit Condylar Sigma (DePuy, Warsaw, Indiana) TKA. Of these, 59 knees developed PC requiring surgery. The mean time to presentation was 10.9 months. The incidence of PC correlated with greater number of previous surgeries (1.18 vs. 0.44, p= 0.002), decreased patellar button size (35.7 vs. 37.1mm, p=0.003), shorter patellar tendon length (54.5 vs. 57.9mm, p=0.01), and increase in posterior femoral condylar offset (1.27mm vs. 0.17mm, p=0.022). Using a patellar component of 32 or 35mm significantly increased the risk of PC compared to the use of a 38 or 41mm component (p< 0.01, RR=1.61, OR 2.63). Modeling results demonstrated decreased patellar tendon length created increased tendofemoral contact near the IB, while larger buttons increased separation between the tendon and the box edge.

Conclusion: Shortened patellar tendon length and use of smaller patellar components may expose the quadriceps tendon to increased irritation as it traverses across the femoral component IB. Increasing posterior femoral offset may increase quadriceps tendon tension, further risking synovial tissue impingement within the IB.


K. Goto H. Akiyama K. Kawanabe K. Sou T. Nakamura

Poly-L-lactic acid (PLLA) is characterized by its biocompatibility and biodegradability, and is used clinically. In our hospital, we started to use PLLA screws instead of metallic or ceramic screws in the fixation of acetabular bone grafts in total hip arthroplasty (THA) in 1990, because there were concerns about the use of rigid and nonbioabsorble screws, which might contribute to the absorption of the grafted bone and induce metallosis or third-body wear when breakage of the screws occurs. The purpose of this study was to review a series of cemented THA for dysplasia, with structural autograft fixed with PLLA screws. We focused on the survival rate of the acetabular component and radiological change of the grafted bone–socket interface.

This study included 104 consecutive cemented total hip arthroplasties (80 patients) performed between July 1990 and December 1995 in our hospital. All patients were followed over 10 years and reviewed retrospectively. The grafted bone trimmed from the excised femoral head was fixed rigidly with 1 or 2 PLLA screws (cancellous lag screws 6.5 mm in bore diameter and 4.1 mm in grove diameter) (Fixsorb; Takiron Co., Ltd., Osaka, Japan).

X-ray photographs taken just after the primary operation showed an obscure but still visible radiolu-cent region corresponding to the inserted PLLA screws in many cases.

However, X-ray photographs at the final follow-up showed an unclear radiolucent zone at the sites of the PLLA screws, and the osteosclerotic line surrounding the site where the radiolucent zone had been found was confirmed in only 4 cases. Bone union was confirmed radiologically at the grafted site in every case, and there were no cases of early collapse or extravasation of the grafted bone. No positive resorption of the grafted bone was observed in any case. Kaplan–Meier survivorship analysis of socket revision, radiological loosening of the socket, and the appearance of a radiolucent line > 1 mm in the graft–socket interface as the endpoints indicated survival rates of 99%, 97.1%, and 63.5% at 10 years, and 96.6%, 90.2%, and 56.1% at 15 years, respectively.

The results of this study indicated that PLLA screws are safe and useful for the fixation of acetabular bone graft concomitant to cemented THA with a careful rehabilitation program. However, because of concern about the mechanical insufficiency of the PLLA screws for THA with an early weight-bearing rehabilitation program, we have used mechanically stronger and bioabsorbable screws made of forged composites of hydroxyapatite and PLLA since 2003.


J. Chouteau J.L. Lerat R. Testa B. Moyen M.H. Fessy S.A. Banks

Mobile-bearing total knee arthroplasty was developed to provide low contact stress and reasonably unrestricted joint motion. We studied the results of a cementless, posterior cruciate ligament (PCL)-retaining total knee arthroplasty (TKA), with a mobile-bearing insert in rotation and anterior-posterior (AP) translation (Innex® Anterior-Posterior Glide, Zimmer).

Kinematic analyses were performed on a series of 51 primary TKA. The patients’ mean age was 71±8 years at operation. Patients were studied at 23 months average follow-up with weight-bearing radiographs at full-extension, 30° flexion and maximum flexion (“lunge” position). Three dimensional position and orientation of the mobile-bearing relative to the femoral and the tibial component during flexion were determined using model-based shapematching techniques.

The average weight-bearing range of implant motion was 110°±14°. In flexion, the mobile-bearing was internally rotated 3°±3° with respect to the femoral component (p< 0.0001) and the tibial tray was internally rotated 5°±7° with respect to the mobile-bearing (p< 0.0001). On average, the mobile-bearing did not translate relative to the tibial base plate from full extension to 45° flexion [0±2 mm (range −5 mm to 6 mm)]. However, the mobilebearing did translate anteriorly 1±2 mm (range −2 mm to 9 mm, p< 0.0001) between 45° flexion and maximal flexion.

We conclude that the mobile-bearing insert showed a progressive increase in internal rotation during flexion. Most of this rotational mobility occurred between the mobile insert and the tibial base plate. With flexion, AP translation did occur between the femoral component and mobile-bearing, and between the mobile-bearing and tibial base plate, but mobile-bearing translation was unpredictable with this unconstrained design.


M. El Hachmi M. Penasse JP. Forthomme

The clunk syndrome is a rare complication of the posterostabilized total knee arthroplasties.

In the literature, there is a lot of aetiologies described concluding to a multifactorial disease.

The aim of our study is to analyse the risk factors described in the literature in a serie of clunk syndrome occurring in three different prosthesis.

We retrospectively analyzed all our cases of clunk syndrome. We compared radiographic values before and after the intervention: the Insall-Salvati ratio, the joint line modification, the thickness of the patella and position of the tibial tray. We compared the appearance of the clunk in three different types of new generation prosthesis: Scopio NRG (Stryker), Legacy (Zimmer) and Sigma (DePuy). The bone scan was done preoperatively to confirm diagnosis.

There are four cases of clunk in each group of prosthesis which represents an mean incidence of 0,5 %. All the clunks occurred in female patients. There is three bilateral cases and one homolateral recurrence. We find no difference in the preoperative values compared to the postoperative status. There is no difference between the three groups. The bone scan was done in eight cases and returned positive in seven cases.

All our cases of clunk syndrome occurred in female patients which is our first risk factor. Doing a clunk syndrome on one side is a great risk factor of doing a clunk on the other side if implanted. The diagnosis of the syndrome is mostly clinical but the bone scan is frequently positive.

The patellar clunk syndrome remains a rare complication of posterostabilized TKA.

Being a woman and one episode of clunk are two risk factors. In presence of symptoms, the bone scan is a reliable preoperative exam to confirm the diagnosis.


J. Kinder V. Rawlani L. Puri

Patients with a thrombotic history are thought to be at greater risk for developing blood clots following total hip arthroplasty (THA) or total knee arthroplasty (TKA). The incidence of venous thromboembolism and risk factors associated with clot development in this population of patients, however, are not well defined.

From the years 2002 to 2008, 547 patients undergoing elective joint arthroplasty with a history of thrombotic disease, defined by prior history of deep venous thrombosis (DVT) or pulmonary embolism (PE), were followed prospectively for a minimum of one month after TKA or THA. Patients received prophylactic anticoagulation with coumadin starting on POD 1 with or without bridge therapy with low molecular weight heparin (LMWH). Patients were compared for the following risk factors: advanced age (> 70 years old), inherited or acquired thrombophilia, time elapsed since prior episode, association of prior episode with surgery, and method of anticoagulation.

Of the 547 patients, 72 (13.2%) developed symptoms consistent with DVT or PE. Thirty-two thromboembolic events (5.9%, 26 DVT, 6 PE) were confirmed by lower extremity Doppler ultrasound, spiral computerized tomography or ventilation-perfusion scanning. 60% of events occurred before POD 3, and the average INR at the time of diagnosis was 1.67. The incidence of thromboembolism was 14.6% and 9.9% for unilateral TKA and THA, respectively and 27.6% and 25% for bilateral TKA and THA, respectively. The institutional rate of DVT during that same time frame is 1.9%. History of inherited or acquired thrombophilia (p< 0.01), time elapse since prior thrmoboembolic event (p=0.04), and association of prior events with surgery (p=0.02) significantly increase the risk of thromboembolism in this population. Bridge therapy with LMWH of any dose did not significantly reduce the risk of DVT or PE, however, there was a trend towards significance (p=0.17). Eight patients (1.5%) experienced bleeding complications; 6 were major in nature (gastrointestinal bleeding and joint hematoma).

Patients with a thrombotic history are at increased risk for developing DVTs after joint arthroplasty. These patients share the same risk factors for development of DVT or PE then patients without a history of prior events. Furthermore, thromboembolic events tend to occur early following surgery in these patients and treatment with LMWH may help reduce the risk of developing clots when used in combination with coumadin.


J.-L. Briard P. Witoolkollachit G. Lin

Stability in TKR is provided by the prosthesis design, weight bearing, alignment and soft tissue envelope which triggers proprioception and neuromuscular control. For long survivorship, the least constrained design are prefered whenever possible. Today there is a discussion about the best prosthetic femoro-tibial alignment as discussed widely in Europe and more recently by Pagnano.

Total knee replacements must be very stable to improve the function and the wear. We certainly performed too many releases in the past and misunderstood some of the fine tuning between posterior structures and collateral ligament frame. Technique in release tends to be more elaborated in order to address sequentially primary and secundary restraints. Release of the lateral structures often created excessive laxity in the past and can be addressed with translocation of the ligaments insertions.

In case of elongated collateral structures, preserving the posterior cruciate and reconstruction of the collateral ligament allows use of less constrained prosthesis.

In revision arthroplasty, the condition may be even more complex but usually the collateral ligaments may be identified. It is usually possible to find and reconstruct their insertions especially on the femoral side. Sometimes, augmentation will be needed but at the end, there is a good functional collateral ligament frame.

Deformities with different soft tissues conditions and with extraarticular components in primary and revision total knee arthroplasty will be reported in severe varus, valgus and stiff knees.


J.H. Yang J.G. Seo M.H. Kim Y.W. Moon J.G. Kim

We aimed to analyze the clinical results of the patients according to joint line change who underwent navigation assisted cruciate ligament retention type mobile bearing total knee arthroplasty.

From September 2004 to January 2006, cruciate ligament retention type mobile bearing total knee arthroplasties using navigation system(Orthopilot®, Aesculap) were performed for 50 knees in 45 patients (2 men, 43 women). The mean follow up period was 46(39~55) months and the mean age was 65. There was one case with rheumatoid arthritis and all other were degenerative arthritic cases. All surgeries were performed using navigation system. Proximal tibia resection was performed at the sclerotic level of medial tibial plateau. The distance from the lowest point of lateral tibial plateau (registered point) to the proximal resection plane was measured. Clinical outcome were compared between joint line elevation with more than 3 mm(20cases) and less than 3mm (30cases).

The mean joint line elevation was 1.93 mm (range −1~5mm). There were no significant difference in the clinical results according to the joint line change (p> 0.05). It may be suggested that the change of joint line in the range of −1 to 5mm in cruciate ligament retention type mobile bearing total knee arthroplasty result in satisfactory clinical outcome.


R. Nagamine D. D’Lima S. Patil W. Chen K. Kondo M. Todo T. Hara Y. Sugioka

Routinely in TKA, at least one of the cruciate ligaments are sacrificed. The cruciate ligaments excision may have an impact in the stability of the reconstructed knee by virtue of the impact on the gap kinematics. In this study, a selective cutting protocol was designed to quantify the individual contribution of ACL and PCL about the knee by means of a loaded cadaveric model.

Five fresh frozen normal cadaver specimens were used. The femur was fixed to a specially designed machine, and 3D tibial movements relative to the femur and joint gap distances were measured by means of a navigation system from full extension to 140° flexion. The joint was distracted with 10 pounds. The measurement was performed before and after ACL and PCL excision.

Medial gap distance at 90° flexion before and after cruciate ligaments excision was 4.3 ± 2.7 mm (mean ± SD) and 5.1 ± 2.8 mm (p< 0.05) respectively. Cruciate ligaments excision significantly widened the medial and lateral gaps at many flexion angles, and the effect of excision on the gap distance was different between medial and lateral sides especially at 90° knee flexion. Cruciate ligaments excision also significantly influenced knee kinematics. If this varying gap is not accounted for either through implant shape and orientation or through soft tissue adjustments, instability could be the result.

Surgeons should be made aware of the influence of cruciate excision on varus/valgus laxity throughout the range of motion. Design modification of the femoral component may also be necessary in order to obtain optimal stability in deep flexion.


P. Boesch W. Huber R. Legenstein

Objectives: To evaluate the outcome of a cementless, low carbon MOM (metal on metal) THR with a 28mm ball-head (PPF STRATEC-SYNTHES, since 2002 BIOMET) and the concentration of metal ions within the intra-articular fluid.

Methods: 173 unilateral MOM THR’s performed in 1995 were investigated. Average follow up time was 12 yrs (range 9–14yrs). During the study period there were, 11(6.4%) deaths, 2 (1.2%) lost to F.U. and 5 (2.9%) refused follow up x-rays because of lack of symptoms, and a self perceived perception that these were not necessary. 41 effusions in part of this group could be analysed for levels of Co, Cr and Ni.

Results: 112 THR’s (64.7%) were completely symptom free and did not show any signs of osteolysis. 7 THR’s had revision surgery, unrelated to metallosis (1 cup loosening, 1 early infection and 5 late infections that could be attributed to a large amount of necrotic tissue within the joint space). 36 hips (20.8%) showed over time, progressive signs of a metallosis. Clinically none or moderate complaints in the groin were reported, and massive effusions of up to 90ml were present. The osteolysis began in the majority of these cases in the periosteal region of the acetabulum and the trochanter. No loosening of the implants was seen. A quarter of these implants had late dislocations. The CRP was up to three times above normal levels. Only 26 patients (15.0%) could be convinced to undergo further surgery (synovectomy, exchange of head and liner and bone grafting as required). Typical histology showed massive necrosis within the joint and a peri-vascular infiltrate of CD-3 pos. activated T-lymphocytes and L26 pos. B-lymphocytes. These findings have been recently published as ALVAL.

In the 41 joint effusions, the mean level of Co was 595.6 μg/l (max 4802.2), Cr 481.1 μg/l (max 4602.9) and Ni 3.7 μg/l (max 14.4). The serum ion levels were up to four times the maximal permitted level (Co 3 μg/l, Cr 3 μg/l, Ni 3 μg/l).

Conclusion: High levels of toxic metal ions in the joint space over time can lead to a severe allergic reaction and tissue necrosis.

The current literature reports, that almost all MOM bearings show slightly elevated serum metal ion levels, and therefore a much higher concentration must be calculated within the joint space. In our experience, because of the serious consequences and unpredictable onset of metallosis, we no longer use MOM articulations.


R.H. Kim D.A. Dennis C.C. Yang B.D. Haas

Introduction: Common failure modes of revision total knee arthroplasty (TKA) include aseptic component loosening and damage to constraining mechanisms which are often required in revision TKA. Mobile-bearing (MB) revision TKA components have been developed in hopes of lessening these failure mechanisms. Our objective was to evaluate the early clinical outcomes for the use of MB in revision TKA with a minimum 2-year follow-up and to evaluate bearing complications.

Methods: Retrospective clinical and radiographic evaluation of 84 MB revision TKAs with minimum 2-year follow-up was performed. Revision TKAs were performed using PFC Sigma and LCS revision rotating platform implants (Depuy, Warsaw, IN).

Indications for revision include aseptic loosening (31 knees), instability (30 knees), failed unicompartmental knee replacement (8 knees), infection reimplantation (7 knees), arthrofibrosis (3 knees), chronic hemarthrosis (3 knees), failed patellofemoral replacements (1 knees), and nonunion of a supracondylar femur fracture (1 knee).

Results: At a mean follow-up of 3.7 years, the average Knee Society clinical and function scores had increased from 50.3 points preoperatively to 89.1 points and from 49.3 points to 80.1 points, respectively. Average motion improved from 99.8° preoperatively to 116.5° postoperatively. Radiographic review demonstrated excellent fixation with no evidence of component loosening upon latest follow-up. No cases of bearing instability were observed.

Conclusion: This evaluation of 84 MB revision TKAs has demonstrated favorable early results at a mean follow-up of 3.7 years with no occurrence of bearing instability. Longer follow-up is required to evaluate for potential advantages of reducing polyethylene wear, lessening fixation stresses, and protection of constraining mechanisms.


P. Zeng W.M. Rainforth B.J. Inkson T.D. Stewart

Retrieved alumina-on-alumina hip joints frequently exhibit a localised region of high wear, commonly called ‘stripe wear’. This ‘stripe wear’ can be replicated in vitro by the introduction of micro-separation, where the joint contact shifts laterally reproducing edge loading during the simulated walking cycle. While the origin of stripe wear is clearly associated with the micro-scale impact resulting from micro-separation, the wear processes leading to its formation and the wear mechanisms elsewhere on the joint are not so well understood. The purpose of this study was to compare the surface microstructure of in vivo and in vitro alumina hip prostheses, and investigate the origins of the damage accumulation mechanisms that lead to prosthetic failure.

The in vivo alumina hip prosthesis was Biolox (Ceram-Tec, AG, Plochingen, Gemany) implanted for 11 years [1]. The in vitro alumina hip prosthesis was Biolox-forte (CeramTec, AG, Plochingen, Gemany), which had been tested in a hip joint simulator under micro-separation at Leeds University using the procedures given in [2]. The worn surfaces of the alumina hip prostheses were investigated using a Scanning Electron Microscopy (SEM). Similar worn surfaces were seen for both in vivo and in vitro samples. Focused ion beam (FIB) microscopy was used to determine the sub-surface damage across the stripe wear. Samples were subsequently removed for Transmission Electron Microscopy (TEM). Sub-surface damage was found to be limited to a few μm beneath the surface; ~ 2μm for in vivo samples and ~1μm for in vitro samples. The transition from mild wear to more severe (stripe) wear was entirely triggered by intergranular fracture. The first stages of fracture lead to the liberation of surface grains which act as 3rd body abrasives. The TEM showed that abrasive grooves are associated with extensive surface dislocation activity, which leads to further grain boundary fracture.

This allows the cycle to be repeated and accelerated, thus yielding the stripe wear region.

The conclusions are: 1. In vitro hip simulation with micro-separation can produce similar microstructure to in vivo alumina hip prostheses; 2. To extend the life of the joint through the avoidance of severe wear, material and design solutions can be investigated using ceramic materials that have an increased surface inter-granular fracture toughness and component designs with reduced contact stress under edge loading.


Youn-Soo Park Young-Wan Moon Seung-Jae Lim Jin-Hong Kim

As the proximal femoral bone is generally compromised in failed hip arthroplasty, achievement of solid fixation with a new component can be technically demanding. Recent studies have demonstrated good short-term clinical results after revision total hip arthroplasty using modular distal fixation stems, but, to our knowledge, none have included clinical follow-up of greater than 5 years. The purpose of this study was to report the clinical and radiographic outcomes assessed 5 to 10 years following revision total hip arthroplasty with a modular tapered distal fixation stem.

We retrospectively evaluated 50 revision total hip arthroplasties performed using a modular tapered distal fixation stem Between December 1998 and November 2003. There were 15 men (16 hips) and 34 women (34 hips) with a mean age of 59 years (range, 36 to 80 years). The index operation was the first femoral revision for 46 hips, the second for 3 hips, and the fifth for 1 hip. According to the Paprosky classification, 5 femoral defects were Type II, 31 were Type IIIA, and 14 were Type IIIB. An extended trochanteric osteotomy was carried out in 24 (48%) of the 50 hips. Patients were followed both clinically and radiographically for a mean of 7.2 years.

The mean Harris hip score improved from 54 points preoperatively to 94 points at the time of the latest follow-up. The mean stem subsidence was 1.5mm. Three stems subsided more than 5 mm, but all have stabilized in their new positions. During follow-up, a total of 4 hips required additional surgery. One hip had two-stage re-revision due to deep infection, one had liner and head exchange for alumina ceramic head fracture, and the other two underwent isolated cup re-revision because of aseptic cup loosening and recurrent dislocation, respectively. No repeat revision was performed due to aseptic loosening of the femoral component. Complications included 6% intraoperative fractures, 4% cortical perforations, and 4% dislocations. There were no stem fractures at the modular junction.

The medium-term clinical results and mechanical stability obtained with this modular tapered distal fixation stem were excellent in these challenging revision situations with femoral bone defects.


M Kurita T Tomita K Futai T Yamazaki Y Kunugiza M Tamaki M Shimizu M Ikawa H Yoshikawa K Sugamoto

Mobile-bearing (MB) total knee prostheses have been developed to achieve lower contact stress and higher conformity than fixed-bearing total knee prostheses. However, little is known about the in vivo kinematics of MB prostheses especially about the motion of polyethylene insert (PE). And the in vivo motion of PE during squat motion has not been clarified. The objective of this study is to clarify the in vivo motion of MB total knee arthroplasty including PE during squat motion. Patients and methods: We investigated the in vivo knee kinematics of 11 knees (10 patients) implanted with PFC-Sigma RPF (DePuy). Under fluoroscopic surveillance, each patient did a wight-bearing deep knee bending motion. And motion between each component was analyzed using two-to three-dimensional registration technique, which uses computer-assisted design (CAD) models to reproduce the spatial position of the femoral, tibial components, and PE (implanted with four tantalum beads intra-operatively) from single-view fluoroscopic images. We evaluated the range of motion between the femoral and tibial components, axial rotation between the femoral component and PE, the femoral and tibial component, and the PE and tibial component, and AP translation of the nearest point between the femoral and tibial component and between the femoral component and PE.

Results: The mean range of hyper-extension was 2.1° and the mean range of flexion of 121.2°. The femoral component relative to the tibial component demonstrated 10.4° external rotation for 0–120 degrees flexion. The tibial component rotated 10.2° externally relative to the PE and the femoral component minimally rotated relative to the PE within ± 5 degrees. In upright standing position, the femoral component already rotated externally relative to the tibial component in 6.3°, and the PE also rotated on average 6.4° externally on the tibial tray. Typically the femoral component relative to the tibial component exhibited a central pivot pattern external rotation from extension to 80° knee flexion. Subsequently from 80 to 120°, bilateral condyles moved backward. In a similar fashion, the femoral component relative to the PE exhibited a central pivot pattern external rotation from extension to 70° knee flexion and subsequently bicondylar rollback from 70 to 120° knee flexion.

Discussion and Conclusion: In this study, we evaluated the in vivo motion of PE during squat motion. About this total knee prosthesis, the mobile-bearing mechanism which advantages over fixed-bearing prosthesis to reduce contact stress and keep high comformity might work well, and arc of range of motion was maintained. Furthermore, in upright standing position, the femoral component and tibial component already rotated externally relative to the PE in almost equal measure. This indicated that, self-aligning mechanism, another characteristic of the MB prosthesis might also work well.


Peter S. Walker David J Cleary Yonah Heller Gokce Yildirim

The objective was to develop a simple, rapid, and low-cost method for evaluating proposed new Total Knee (TKA) designs, and then to use the method to evaluate three different TKA models with different kinematic characteristics. In a previous study, we reported on the use of an Up-and-Down Crouching Machine, where the neutral path of motion for knee specimens were measured, and then TKR models were implanted and the tests repeated. These experiments showed that standard CR and PS designs behaved more like an ACL deficient knee, whereas Guided Motion knees produced motion similar to that of the intact specimens. However the method was time consuming, technically demanding, and expensive, and hence is suitable for designs which had already passed through a screening method. The latter was the subject of this present study, called the Desktop TKR Test Machine.

The principle of the testing protocol on the machine, called Holistic Testing, was that a spectrum of compressive, shear and torque forces were applied to a knee, to represent a complete spectrum of daily and sporting activities. The resulting femoraltibial positions were measured, both the Neutral Path of Motion and the Laxity about the neutral path. The motions were displayed as both the motion of the transverse femoral axis on the tibial surface, and by the centers of the lateral and medial contact patches.

Eight knee specimens were tested first, to act as a reference target for evaluating TKR models. Knee models were designed in the computer and made in a hard low-friction plastic using SLA and stereolithography.

A typical Posterior-Stabilized (PS) TKA did not display the normal external femoral rotation with flexion, and also showed abnormal anterior sliding on the medial side prior to cam-post engagement. Guided Motion designs included a Medial Pivot type, and a Medial Pivot with a cam-post. Both of these had a dished medial side and a shallow lateral side, to more accurately reproduce anatomic motion characteristics. The guidedmotion design with the cam-post produced a neutral path and laxity more similar to that of normal.

It was concluded that the test method satisfied the objective in terms of being a useful test method for rapid evaluation of new proposed TKR designs. The method was able to identify designs which showed motion and stability characteristics closer to the normal anatomic knee.


J.T. Moskal S.G. Capps

Many factors can negatively impact acetabular component positioning including poor visualization, increased patient size, inaccuracies of mechanical guides, and inconsistent precision of conventional instruments and techniques, and changes in patient positioning. Improper orientation contributes to increased dislocation rates, leg length discrepancies, altered hip biomechanics, component impingement, acetabular component migration, bearing surface wear, and pelvic osteolysis thus affecting revision rates and long-term survivorship. Despite the established definitions of acetabular safe zones, recent analysis of U.S. Medicare THA data found dislocation rates during the first six months to be 3.9% for primary surgeries and 14.4% for revision surgeries. Accurate and precise acetabular component orientation during initial THA is an increasingly important factor in decreasing revision THA; a recent report cites instability and dislocation as the primary cause of revision accounting for 22.5% of cases. Larger femoral heads and alternative bearing couples are less tolerant of variation in acetabular orientation and thus are poor substitutes for proper acetabular component placement.

Variability in acetabular orientation has been reported to have both an inter-surgeon and an intra-surgeon component; pre-surgical templating combined with intraop-erative measurements is subject to inconsistencies and errors. Current methods for determining acetabular orientation include preoperative imaging such as CT scans, intraoperative imaging such as plain radiographs and fluoroscopy, and intraoperative anatomical tests. Combining the concepts of patient-specific morphology (PSM) and quantitative technologies (QuanTech) such as computer-assisted navigation (CAN) has the potential to maximise range of motion and to further improve acetabular component orientation through improved accuracy and precision.

PSM refers to the practice of allowing the form and structure of the patient’s hip joint to guide surgical reconstruction and component placement thus creating an individualised and more accurate “target zone”; unlike “safe zones,” PSM does not rely on averages. Although gross anatomic changes may make it difficult to use PSM, certain structures may be used as guide-posts for orientation, alignment, and stability in most patients. At present, there are three options when considering anatomic landmarks as guides for acetabular component placement: bony landmarks, soft tissue landmarks, or a combination.

QuanTech has been shown to increase the precision of component placement by reducing intra-surgeon deviation. Some pitfalls of current CAN techniques result from maintaining camera line of sight during surgery, registration process, and pin placement. Performing THA using smaller incisions can impose additional complications as well as risks for errors in component positioning; QuanTech has the potential to provide greater visualization and precision, thus decreasing the impact of those constraints.

THA has become one of the most common and successful orthopaedic procedures; its efficacy at relieving pain and its ability to help patients have improved quality of life is without dispute yet results continue to vary with inter-surgeon and intra-surgeon differences. As the population needing THA increases, the prevalence of complications and problems will increase, even if the percentage of complications decreases. Coupling PSM with QuanTech such as CAN may allow the surgeon to decrease variability and more consistently implant THA components based on each patient’s individualized requirements. The goal of combining PSM and CAN is to further reduce inter-and intra-surgeon variation, thereby decreasing outliers, complications, and revision rates, and possibly narrowing the gap between specialist and generalist. More accurate and precise acetabular component orientation correlates with better hip biomechanics, translating into better function, fewer dislocations, fewer impingements, maximized safe range of motion, less wear, and therefore less aseptic loosening and improvements in survivorship of primary THA. Decreasing revision rates, combined with the benefits listed above, could translate into increased THA survivorship, improved patient satisfaction, and decreased economic burden on the entire healthcare system.


T. Nakamura C. Fukuda M. Imamura K. Goto T. Kokubo

Many types of bioactive bone cement have been developed to overcome the disadvantages of polymethyl-methacrylate (PMMA) bone cement, especially its lack of bone-bonding ability, which occasionally leads to aseptic loosening of prostheses used for arthroplasty. Earlier, we showed that bioactive bone cements containing either nano-sized or micron-sized titania (TiO2) particles had excellent in vivo osteoconductivity.

However, anatase phase titania particles contained in these bioactive bone cements raise concerns about their safety in vivo. We developed pure rutile micron-sized titania particles. because rutile is the only stable phase, whereas anatase is metastable.

In this study, polymethylmethacrylate (PMMA)-based bone cement containing pure rutile micron-sized titania (TiO2) particles were developed, and their mechanical properties and osteoconductivity are evaluated. The three types of bioactive bone cement were T10, T20, and T30, which contained 10, 20, and 30wt% TiO2, respectively.

Commercially available PMMA cement (PMMAc) was used as a control. Hardened cylindrical cement sample (φ2.5mm*10mm) was inserted manually on rabbit femur vertically. Push out test was performed for evaluation of bonding strength. For mechanical testing, the flexural strength, flexural modulus, and compressive strength were measured.

Results of this study revealed that polymethylmeth-acrylate (PMMA)-based bone cement containing pure rutile micron-sized titania particles has outstanding osteoconductivity in vivo, and their mechanical properties were exceeded that of commercially available PMMA cement. Interfacial shear strength of T10, T20 and T30 were 17.1~24.0MPa each at 12 weeks, and were significantly higher than PMMAc. In general, the interfacial bonding strength of bone cement depends mainly on its interdigitation with cancellous tissue, which is accomplished by the pressurized injection of the cement in paste form. On the other hand, we inserted the hardened specimens into oversized holes on rabbit femur in this study, because we intended to examine the osteoconductive and bone-bonding potentials of each material. The flexural strength, flexural modulus, and compressive strength were equivalent to or exceeded that of PMMAc.

These results show that bone cement containing pure rutile micron-sized titania particles is a promising material applied to prosthesis fixation as well as vertebroplasty.


N.P. Jain M. Granieri M. Polavarapu S.D. Stulberg

The focus of deep vein thrombosis (DVT) prophylaxis following total joint arthroplasty has shifted in recent years to the reduction of symptomatic pulmonary emboli (PE). The relative infrequency and presumed delayed occurrence of these events has led many to suggest that the risks of more frequent early postoperative complications of treatment, especially bleeding, be weighed against the benefits of thromboembolic prophylaxis. The purpose of this study was to determine the timing and risk factors associated with the development of symptomatic PE following total hip arthroplasty (THA) and total knee arthroplasty (TKA).

A retrospective analysis was performed of all patients diagnosed with a symptomatic pulmonary embolism following THA and TKA performed from January, 2004 to March, 2008. The records of 4706 patients were reviewed who were operated upon by 7 surgeons, and a total of 58 PE were identified. All patients were managed and treated by an anti-coagulation dosing service. Helical CT Scans were used to make the diagnosis of PE.

The overall incidence of PE was 1.2%, with 1.8% occurring in TKAs and 0.5% occurring in THAs. 48 of the 58 PE patients (83%) were women. 33 patients (57%) had unilateral TKA, 14 (24%) had bilateral TKA and 11 (19%) had THA. The average patient age was 65 (range: 44–88) and BMI was 33.8 (range: 24.7–51.9). There was no apparent correlation between age and BMI with incidence of PE. The PE were diagnosed an average of 4 days (range: 1–46) following surgery. 56 of the 58 patients (97%) were diagnosed by the sixth postoperative day. The average INR at the time of diagnosis was 1.7 (range: 1.0–3.0). There were two mortalities (3%), both of which occurred within the first two postoperative days.

The PE in this study occurred predominantly in women undergoing TKA. There appears to be an urgent need to develop an effective prophylaxis program aimed at preventing PE in the early post-operative period and to identify patients at risk of these PE.


M. Bercovy D. Hasdenteufel S. Delacroix N. Legrand M Zimmermann

This study aims to compare the gait pattern of patients operated with a TKA versus a normal population in order to evaluate if the excellent function of TKA reported in the literature corresponds to objectively measured parameters.

20 patients operated of TKA with a follow up > 1 year, all patients rated with a very good functional result (Knee Society Knee score > 85/100 – VAS < = 1/10) were compared with a group of 20 “ normal” persons.

The study was blind: the examiner did not know whether the person was a normal, or which knee was operated.

The test consisted in an 11 meters walk, on an AMTI force platform; the movements of the body were recorded with 6 IR cameras and analysed with the “Motion Analysis” software.

The implant was a mobile bearing AP stabilised knee.

The measured parameters were kinematic : speed, step length, flexion angle, duration of stance /WB phase and dynamic : flexion/extension, varus/valgus, internal/ external moments and resultant force direction. When matched with age and BMI, all kinematic parameters of the TKA group are equal to that of the normals.

However, dynamic parameters differ significantly between both groups: At the end of stance phase and heel strike the operated patients have a lack of extension of 10° despite a clinical measurement of full extension (0°) In the frontal plane, all patients exhibited a valgus walking pattern but the mechanical axis measured on long standing radiographs was 180°+/−1°. In the horizontal plane, all operated patients had an external rotation of +8° compared to the normals.

Despite excellent clinical scores and radiologic positioning, gait analysis demonstrates important dynamic differences between the TKA and the normal group. The extension lag at heel strike may be related to either quad weakness, or an insufficient extension gap at surgery; The valgus resultant pattern occurs despite a perfect alignment of the mechanical axis (180°) on the operated patients: this rises the question whether this alignment is the goal or if an undercorrection would be more physiologic. External rotation is superior to the normal group : it is in relation with the external rotation of the femoral and tibial components.

Conclusion. Gait analysis of the TKA group of patients compared to normal demonstrates important dynamic differences in relation with the surgical positioning of the implant.


G. Gasparini G. Maistrelli V. De Santis

Background: Poor results were observed at medium term follow-up (FU) after first and second generation cementless stems implantation in total hip arthroplasty (THA). Revision rate up to 24% is reported with anatomic stems; stress-shielding rate up to 50%, thigh pain rate up to 21%, loosening rate up to 20% and osteolysis rate up to 29% were reported with cylindrical stems. A third generation tapered stem, the Synergy stem, was introduced in 1996 to rise such weakness points.

Material and methods: A retrospective, cohort study was carried out in two academic centers (London, Toronto, Canada & Rome, Italy) on 232 primary THA in 215 patients with a 10 to 12 yrs FU. Mean age at surgery was 60 yrs (18–82), 95 patients were males and 120 females. Thirty-six patients were lost at FU (13 died before the 10 yrs mark, 22 changed residency, 1 not willing to be seen) with no problems related to the replaced hip. Remained at FU 196 THA. Patients selection: Dorr type A and B femurs suitable for receive a Synergy stem. Its characteristics are the following: Ti-6Al-4V, straight, tapered, 3D wedge cross-section, proximal antirotational fins, low-profile neck, neck angle 131°, metaphyseal part porous or HA coated, diaphyseal part grit blasted, polished tip, surgeon-friendly ancillary instruments. Clinical results of the 196 THA with more than 10 yrs of FU were assessed preoperatively and postoperatively at 5 and 10 or 11 or 12 yrs by means of standard evaluation tools: SF12, WOMAC and Harris Hip Score. Thigh pain frequency and intensity were also scored. Radiographic analysis was focused on stem alignment, bone ingrowth, radiolucent lines presence, width and progression, stress-shielding, heterotophic ossification (HTO). Student paired test and Kaplan-Meier survival analysis were used for statistical analysis.

Results: All clinical evaluation tools showed both at 5 years FU and at latest FU (10–12 years) a statistically significant (p=0,001) improvement compared to the preoperative scores. We observed a not constant thigh pain in 7 patients (5,5%). Nineteen patients (10%) underwent evision due to polyethylene wear (6 cases), late periprosthetic fracture (5 cases), subsidence (2 cases), instability (3 cases), infection (3 cases). Cumulative survival rate was 97% at 2 and 5 years, 90% at 10 years. Stem related revisions were the 2 cases of subsidence, both related to occult intraoperative calcar crack and early revised (within 1 year); cumulative stem-related survival rate at 10 years was 99%. Alignment was varus in 9 cases and valgus in 3. Bone in-growth was observed in 194 patients (98%). Radiolucent lines were uncommon, non progressive, less than 2 mm, in Gruen zones 2 and 6. Stress-shielding was present as cortical reaction in 5 femurs in Gruen zones 3 and 5. Thirty-four cases of HTO (grade I and II in 27 case and grade III in 7 cases) were observed.

Conclusions: The Synergy stem demonstrates excellent clinical and radiographic results at 10–12 yerars FU in 196 patients. Survivorship (with stem revision as end point) is 99% at 10 years. Thigh pain is uncommon and the level of activity and autonomy is excellent. Radiographically bone ingrowth is evident in all stems and radiolucent lines are “benign” with no aseptic loosening. Attention must be paid at the moment of stem press fit insertion to avoid occult proximal femoral fractures that may require revision surgery.


Kwang-Jun Oh

Background: The purpose of this prospective study was to asses the reliability of image-free navigated cup positioning and its correlation with biometrical parameters (age, sex, body mass index, soft tissue thickness overlying anterior superior iliac spine and symphysis pubis, and lumbar lordosis) and three different orientations of pelvis (tilt, obliquity, and rotation) in patients of Asian ethnicity.

Methods: Intraoperative data was obtained from 50 consecutive total hip arthroplasties in which acetabular cup implantation was done with a cementless cup (Plasma Cup SC®, Aesculap AG, Tuttlingen, Germany) using Orthopilot® image-free navigation system. The data was then compared with mathematically calculated synchronized anteversion and inclination obtained postoperatively through computed tomography and 3-dimensional processing.

Results: Mean navigated and synchronized inclination obtained were 40.1°±5.34° and 41.79°± 7.96° respectively (mean difference 1.69°±6.95°, range −20.72° ~ 18.47°), while the mean navigated and synchronized anteversion were 19.98°± 6.44° and 20.00°± 6.33° (mean difference 0.01°±6.35°, range −15.15° ~ 11.10°). A discrepancy of > 10° was observed in 5 hips in inclination and 5 hips in anteversion. No correlation was found between all of biometrical parameters and discrepancy of cup orientation. A statistically significant correlation was found between discrepancy of anteversion and pelvic tilt (1.78 + 0.55 x pelvic tilt°, r=0.493, p=0.0016).

Conclusion: In spite of variations in pelvic geometry, image-free navigation assisted acetabular cup positioning showed the significant reliability. The next generation of navigation systems must be combined with data on precision of pelvic orientation intraoperatively for complete validation.

*Index; Synchronized Inclination = arctan [tan (Operative AV) ÷ tan (Anatomic AV)] Synchronized AV = arctan[tan (Anatomic AV) x sin (synchronized Inclination)] or arctan[tan (Operative AV) x cos (Synchronized Inclination


Wooshin Cho Yoonseok Yeum Byungkwan Kim Jeho Woo Hoyoun Park

We checked intraoperative patellar tracking with both ‘towel clip technique’ and the ‘no thumb technique’ on 354 patients (571 knees) who underwent primary total knee arthroplasty to decide whether to do or not to do lateral retinacular release.

All surgical procedures consisted of medial parapatellar arthrotomy and patellar resurfacing. Patellar tracking was assessed under pneumatic tourniquette with the no thumb technique first and reevaluated with the towel clip technique. The tracking was graded as total contact, good contact, lateral contact, and subluxation. The knees graded as total or good contact with the no thumb technique were classified into group A; those graded lateral contact or subluxation by the no thumb technique but total or good contact by the towel clip technique were classified into group B; and those graded lateral contact or subluxation by both techniques were classified into group C, in which lateral releases were performed. We classified 371, 148, and 52 knees into groups A, B, and C respectively. Patellar lateral tilting in the Merchant view was reviewed preoperatively and 2 weeks, 6 weeks, 6 months, and 1 year postoperatively.

There were no statistical differences on postoperative patellar tilting among the groups. Assessment of the patellar tracking using only the no thumb technique may overestimate the need for lateral retinacular release. The use of the no thumb technique as a screening test, and reevaluation with the towel clip technique, may reduce unnecessary lateral retinacular release.


W.J. Long G.R. Scuderi

Bone loss is a challenging reconstructive problem in revision total knee arthroplasty (TKA).

Uncemented porous tantalum modular components are designed to act as substitutes for allograft bone in complex revision TKA with significant bone defects.

A consecutive series of 23 revision TKAs performed by a single surgeon were reviewed at a minimum two-years following implantation. In all cases bone loss was assessed using the Anderson Orthopaedic Research Institute System, and porous tantalum components were used to augment the reconstructions when bone loss was encountered.

Twenty-one patients had 23 procedures (2 bilateral) requiring the use of porous tantalum following 18 cases of aseptic loosening, 4 cases of staged re-implantation for infection, and 1 case of a periprosthetic patellar fracture and aseptic loosening. Structural bone graft was not used during this time period. Porous tantalum uses include: 20 distal and posterior femoral augments; 2 femoral cones; 8 patellar augments; and 18 tibial cones. 20 cases required augmentation in more than one area, and one case involved an extensor mechanism allograft. There were 2 cases of recurrent sepsis requiring removal of well-fixed tantalum components. At an average 37 months (24 to 73) no patients were lost to follow-up. Clinical follow-up in the remaining 21 cases showed reconstructions were functioning well with no revisions. Radiographic imaging showed re-establishment of the joint line, neutral mechanical axis, and signs of stable fixation of the augments. There were no cases of radiographic or clinical loosening at the most recent follow-up.

Short term results with the use of porous tantalum augments and cones for bone loss in revision TKA demonstrate the versatile, and durable nature of these new reconstructive tools, at early follow-up.


H. Oonishi H. Oonishi S.C. Kim M. Kyomoto M. Iwamoto M. Ueno

A consensus on total hip arthroplasty (THA) concluded that the major remaining issues of concern included the long-term fixation of the joint replacement, osteolysis due to poluethylene (PE) wear debris which often leads to aseptic loosening. Alumina ceramics had been extensively used in medicine, and we started using the alumina ceramic for THA bearing surface in hopes to reduce the PE debris. It was because alumina ceramics is advantageous for precision machining compared with metal materials, and its hardness is higher than that of metal materials. Also, to augment cement–bone bonding, we interposed hydroxyl apatite (HA) granules at the cement–bone interface, so called “Interface Bioactive Bone Cement (IBBC) technique”. HA granules (2–3 g) were smeared on the bone surface of the acetabulum and femur just before cementing. In this study, we evaluated 19–22 years clinical results of THA with alumina ceramic head combined with PE cup fixated IBBC technique.

Total 285 joints (212 patients) were implanted by one senior surgeon from January 1986 to December 1988, and 265 joints (192 patients) were traceable. Alumina ceramic femoral head of 28 mm in diameter and acetabular cup of the conventional PE sterilized with ethylene oxide gas were used in all patients. The PE cup and stem were fixed with IBBC technique in all cases. The presence of radiolucent line, loosening and osteolysis were observed using radiograph of the traceable cases. The locations of radiolucent lines were identified according to the zones described by DeLee and Charnley for acetabular cups and the zones described by Gruen et al. for femoral stems. The in vivo wear of 21 PE acetabular cups for 19.0–21.9 years (mean 20.3 years) was measured from the latest radiographs using computer assistant technique with Vector Works 10.5 software.

Features of the clinical radiograph images of the IBBC case were classified as follows: the radiolucent line represented “gap” between the HA layer and the cement; the loosening represented “opening” between the HA layer and the cement. For the quantitative analysis, we divided the surrounding bones of the THA into several zones as done in the previous studies. The “gap” appeared in zone 4 in three joints (1.4 %), in zone 3 in two joints (0.9 %) of acetabular cup. In femoral side, in zone 1 in four joints (1.8 %) in zone 7 in one joint (0.4 %). The “opening” appeared in three acetabular cup (1.4 %). Since no opening was appeared in zone 3 or zone 4, however, no re-operation was needed. Images of osteolysis were seen one in zone 1 (0.5 %), and one in zone 2 (0.5 %) in acetabular side and two in zone 1 (0.9 %) of the femur. The mean linear wear rate of PE acetabular cups was 0.13 mm/year.

The fixation to the bone by the IBBC technique has been maintained for long term. We think that the result was brought by the biological integration between bone and HA granules. In conclusion, this study has shown satisfactory results of the cemented THA with ceramic head combined with PE cup for 19–22 years.


S.D. Steppacher M. Tannast J. Kowal G. Zheng K.A. Siebenrock S.B. Murphy

Acetabular component malpositioning increases the risk of impingement, dislocation, and wear. The goal of computer-assisted techniques is to improve the accuracy of component positioning, in particular optimizing the orientation of the acetabular cup.

The goal of the current study was to measure accuracy of cup placement in a large clinical series of hips that underwent CT-based computer-assisted THA.

146 hips in 140 patients underwent CT-based computer-assisted THA between 2006 and 2008. In all cases cup orientation was planned according to the individual preoperative CT and the anterior pelvic plane with an inclination of 41° and anteversion of 30°. For the procedure, all patients were placed in the lateral position and the cup was implanted using angled instruments. Intra-operatively all cases were navigated using an optoelec-tronic camera and tracked instruments (Vector Vision prototype, BrainLab, Germany).

Post-operatively, cup orientation was measured using a previously validated technique of 2D/3D-matching using the preoperative CT and post-operative radiographs. This technique allows for accurate measurement of cup position from plain radiographs corrected for individual pelvic orientation.

The mean accuracy for inclination was −2.5° ± 4.0° (−12° – 10°) and for anteversion it was 0.7° ± 5.3° (−11° – 15°). In 2 hips (1.4%) a deviation of more then 10° in inclination and in 4 hips (2.7%) a deviation of more then 10° in anteversion were found.

The current study demonstrates that the acetabular component can routinely be implanted with the assistance of CT-based navigation with reasonable agreement between the navigation measurements of component orientation at the time of surgery. Nonetheless, outliers still occasionally occur. These might be due to unrecognized loosening of the pelvic reference base, inaccurate registration or the use of the ipsilateral surface-based registration algorithms which rely heavily on points near the center of rotation of the hip.


JY Lazennec MA Rousseau A Rangel Y Catonne

Introduction: Computer assisted total hip replacement (THA) usually uses the anterior pelvic plane (plane of Lewinneck, APP) for reference because the anatomical landmarks are easy to access during the surgical procedure. However, a recent study shows the lack of correlation in between the Lewinnek angle in standing position (L) and the spinal radiological parameters for sagittal balance, specifically the incidence angle and the sacral slope. The anatomical variations of the anterior superior iliac spines account for the discrepancy. The authors propose here the assessment of the Lewin-nek – sacrum angle (LS) (anterior pelvic plane to the sacral endplate) Methods: 120 asymptomatic patients with THA had low dose lateral X-rays of the lumbo-pelvic area (Definium 8000, GE Healthcare ;dose 0,6 mSivert). The measurements of the sacral slope, incidence angle, and APP were done by two independent observers.

Results: The sacral slope and incidence angles were similar to other series. The APP was no clearly identified in 78 cases. The average L angle was −3° (SD 8°) in standing position, −23° (SD 11°) in sitting postion, and −2° (SD 8°) in lying position. The average LS angle was 47° (SD 13°). The geometrical relationship between the LS a ngle, the L angle and the sacral slope is reported.

Conclusion: THA stability supposes that the orientation of the acetabular component shall remain within extreme values in standing, sitting, and lying postures. The adjustment of the acetabulum takes into account the functionnal anatomy of the lumbopelvic area. The sacral slope is a reliable radiological reference and is related to the sagittal balance of the spine. The APP presents some interindividual variability and is poorly visible on the radiographs, but it is easily accessible during surgery. The author suggest using the Lewinnek sacrum (LS) angle for radiological planification and for surgical navigation procedures.


G Suzuki S Saito T Ishii S Mori S Motojima J Ryu

Total knee arthroplasty (TKA) has been proven to be the most effective treatment for patients with severe or “end-stage” joint disease. Although infection is not a frequent complication of total knee arthroplasty, it is certainly one of the most dreaded. The purpose of this study was to identify related factors associated with septic arthritis.

2202 primary total knee arthroplasties were done in 1257 patients between 1995 and 2006. Of these knee arthroplasties, 2022 knees in 1146 patients were available for follow-up. Revision arthroplasty procedures and infected knees were excluded. 252 knees in 147 males, 1770 knees in 999 females were done. Their mean age at the time of primary TKA was 70.6 (range, 26–91) years. The mean follow-up period post primary TKA was 48 (range, 3–145) months. The medical records were reviewed to extract the following information: age, gender, body mass index, preoperative CRP, preoperative ESR, preoperative TP, duration of surgery, operative blood loss, total blood loss, duration of surgical drain, duration of antibiotic prophylaxis, primary diagnoses, smoking, diabetes mellitus, steroid or DMARDs therapy, previous operation around the knee joint, previous arthroscopic surgery, previous except arthroscopic surgery, previous operation of high tibial osteotomy (HTO) or open reduction internal fixation (ORIF), residue of internal fixation material, bone graft, patella replacement, and bone cement.

Proportions were compared using the chi-square or two-tailed Fisher’s exact test, as appropriate. Continuous variables were compared by the student’s t-test. Logistic regression analysis (stepwise) of selected variables from univariate analysis was performed to identify factors independently associated with the development of infection following total knee arthroplasty.

During the study period, 17 infected knee arthroplasties in 17 patients were identified. The infections occurred in 8 males and 9 females, with a medial age of 69.5 years.

The results of univariate analysis indicating those variables statistically associated with infection are : gender (p < 0.0001), smoking (p = 0.02), previous operation around the knee joint (p = 0.001), previous except arthroscopic surgery(p < 0.0001), previous operation of ORIF (p < 0.0001), residue of internal fixation material (p < 0.0001).

Logistic regression analysis indicated that the four predictors of infection following total knee arthroplasty were gender (odds ratio [OR], 0.2; 95% confidence interval [CI95], 0.1 to 0.6; P=0.005), previous operation of ORIF (OR, 7.9; CI95, 1.1 to 57.1; P=0.041), residue of internal fixation material (OR, 26.0; CI95, 4.5 to 151.0; P< 0.001), body mass index (OR, 1.2; CI95, 1.0 to 1.3; P=0.007).

We conclude that the risk factors of infection after TKA were previous operation of ORIF, gender, residue of internal fixation, and body mass index.


R. Patel S.D. Stulberg

Despite the clinical success of uncemented femoral stems of various types, current issues continue to require repeated examination:

proximal-distal mismatch

optimization of load transfer and preservation of femoral bone and

facilitation of MIS (minimally-invasive surgery) exposures, particularly an anterior approach.

A previous study demonstrated that a custom-made (based on CT-scan) short metaphyseal engaging femoral stem design provided stable fixation and reliable bony ingrowth at four-year follow-up. The purpose of this study is to present the minimum two-year clinical and radiographic results obtained with an off-the-shelf metaphyseal filling stem.

An uncemented, metaphyseal engaging femoral stem was inserted in 194 consecutive hips in 181 patients, whose average age was 70 years (range 32–95) and BMI of 28 (range 19–63). The implant, which averaged 94 millimeters in length (range 91–105), was made of titanium alloy with a hydroxyapatite coating on a titanium plasma-spray in the third of the stem.

The average Harris hip score (HHS) was 52 (range 10–80) preoperatively and 91 (range 70–100) postoperatively and no patients experienced thigh pain. Preoperative WOMAC scores averaged 48, compared to a postoperative average of 4. There were no fractures or other complications related to the prosthesis, no radiographic evidence of subsidence, and all stems were radiographically stable on most recent radiographs. The typical pattern of bony ingrowth was that of bone bridging and endosteal condensation at the proximal portion of the stem.

This study demonstrated that the use of an off-the-shelf short femoral stem designed to fit and fill the metaphysis provides reliable clinical and radiographic results at a minimum two-year (average 31 months) follow-up. Short stems may be particularly helpful to surgeons performing total hip arthroplasty using a MIS anterior approach.


Stefan Kreuzer Jonah J Stulberg

Introduction: The Direct Anterior Approach (DAA) for hip replacement is an unfamiliar approach to most surgeons. The challenging portion of this approach is the preparation of the femur. In this study we determine factors that can assist in predicting the difficulty of femoral preparation to improve the learning curve.

Methods: Data was collected prospectively on 151 consecutive cases utilizing the DAA for hip replacement. After each case the femoral preparation was rated into one of 5 categories: very easy, easy, medium, difficult and very difficult. Clinical and demographic data were collected prospectively using web based data entry software. Post-operative x-rays were evaluated by an independent reviewer unaware of the exposure difficulty. Using multivariate regression, we examined several different x-ray based pelvic measurements as predictors for difficulty of femoral exposure.

Results: Univariate analysis demonstrated difficulty of femoral preparation was significantly (p< 0.05) correlated with height (OR=2.67, 95% CI = [1.03–6.94]), weight (OR=8.30, 95% CI=[2.35, 29.35]), male gender (OR=6.11, 95%CI=[1.97–18.97]), the distance from the greatertrochanter-to-ASIS (OR=0.30, 95%CI=[0.11–0.82]), teardrop-to-teardrop (OR=0.29, 95%CI=[0.11–0.79]), and greatertrochanter-to-greater-trochanter (OR=3.31, 95%CI=[1.23–8.95]). From this, we determined a simple pre-operative formula which allows the surgeon to predict difficult femoral preparations with an 87% sensitivity and easy preparations with > 95% specificity.

Conclusion: In MIS hip surgery, the DAA has proven difficult to learn for many surgeons. Careful patient selection can facilitate the learning curve and improve patient outcomes. We describe a simple to implement preoperative rating scale, which gives the surgeon learning DAA an algorithm for appropriate patient selection. With new advances in surgical procedures, selecting the appropriate patient can reduce the risks to the patient and minimize the cost to society of integrating new surgical techniques.


D Parodi J Besomi J Lopez J Lara C Mella L Moya

Long-term functional and degenerative consequences of non treated slipped capital femoral epiphysis (SCFE), have been extensively demonstrated. At present, the treatment of SCFE is well described, however the treatment of the sequelae of SCFE, once osseous consolidation has happened, remains controversial.

Our aim is to describe an original technique of cuneiform osteotomy of the femoral neck through surgical hip dislocation for the treatment of sequelae of SCFE. Six hips were operated with sequelae of severe SCFE; average age of 15,2 years, whose consulting motivation was hip pain and severe limp. All of them, with bony consolidation of the femoral physis at the time of the consultation.

In all cases, it was performed a cuneiform osteotomy of femoral neck and replacement of the femoral epiphysis, through surgical hip dislocation. It was made a dissection and elevation of cervical periosteum to protect the epiphyseal vessels of the femoral head; then, the cuneiform osteotomy of the femoral neck is made with replacement of the femoral epiphysis to anatomical location and fixed.

The mean follow up was 21,2 months. We obtained consolidation in 100% of the cases, did not appear avascular necrosis nor other complications. An improvement was obtained according to Harris Hip Score from 37,6 points to 96,6. Correction of the epiphyseal-shaft angle was obtained from 62° to 12,6°.

This technique proposed in patients with sequel of SCFE is a good alternative of treatment, with good anatomical, functional, clinical and radiological results in young patients, without mid-term complications.


D.A. Heuer M. Williams R. Moss K. Butcher M. Anderson R. Milner C. Alley L. Gilmour M. Scott

This study evaluated the biologic fixation of two different titanium porous coatings: a clinically successful sintered spherical bead coating [1] and a new sintered asymmetric particle coating (STIKTITE™, Smith & Nephew). The spherical bead coating has a porosity of about 50% and an average pore size of about 220 μm, whereas the STIKTITE coating has greater porosity (about 62%) and slightly smaller average pore size (about 200 μm). Biologic fixation was assessed using a load-bearing ovine model in which coated semi-circular disc implants were inserted into a defect created in the cancellous bone parallel to and approximately 3 mm below the medial tibial plateau [2] similar to the method reported by Ignatius [3]. The implants were slightly thicker than the defect created, producing a 0.2-mm overall pressfit. Initial implant stability was assessed using mechanical push-out (n = 3) immediately after implantation into cadaveric ovine bone. Quantitative mechanical push-out testing and qualitative histology (n = 9 and n = 2, respectively, per group per time point) was performed after six and 26 weeks in vivo.

The time-zero average peak push-out load (±S.D.) of the STIKTITE group (95±3 N) was found to be significantly greater (p < 0.02) than that of the spherical bead group (36±5 N). By six weeks in vivo, the average peak push-out load for the STIKTITE group was up to 1001±362 N, and that for the spherical bead group was up to 985±425 N, both representing a significant increase compared to their time-zero results (p < 0.0005). From six to twenty-six weeks in vivo, there was again a significant increase in the peak push-out load irrespective of group (p < 0.0005), with the average peak push-out loads up to 1620±406 N and 1444±446 N for the STIK-TITE and spherical bead groups, respectively. Histology revealed bone ingrowth in both groups that confirmed the findings of the mechanical push-out testing. While the STIKTITE group showed a trend toward greater biologic fixation, overall there was insufficient evidence to support differences between the two groups (p = 0.47) irrespective of the amount of time in vivo.

The results of this study confirm the ability of the STIK-TITE coating to achieve superior initial stability. This improved initial stability reduces the reliance on adjunct fixation (such as screws) or large amounts of press-fit to prevent micromotion and create an environment suitable for long-term bone ingrowth. The results also suggest that the STIKTITE coating had a tendency to initiate and maintain bone ingrowth under load-bearing conditions to a level greater than that of a clinically successful sintered bead coating. Because loading of the implant can cause micromotion at the bone/implant interface, models like the one used in this study likely provide a more challenging and realistic representation of anticipated clinical conditions than models with minimal implant loading.


M.L. Hansen W.J. Ciccone M.C. Jacofsky A. Jaczynski A. Boyles J.C. Otis

Although reverse total shoulder arthroplasty (TSA) may restore shoulder abduction and forward flexion in the setting of a massive rotator cuff tear, the ability to use the extremity for ADL’s is often limited by external rotation weakness. Even though the reverse TSA restores abduction, the patient may be unable to bring the hand to his or her mouth because with the elbow flexed the weight of the hand causes the shoulder to fall into internal rotation. Concomitant transfer of latissimus dorsi (LDT) to the posterior greater tuberosity is a solution advocated by some surgeons. It is hypothesized that this inferiorly-directed force partially counteracts the superiorly-directed force of the deltoid, resulting in decreased shear forces on the glenoid baseplate-bone interface.

Three cadaver shoulder specimens were dissected and implanted with the reverse TSA. The rotator cuff was completely released to simulate a massive rotator cuff tear. Each shoulder was mounted in a shoulder controller that simulates neuromuscular control and replicates in vivo glenohumeral kinematics. The controller utilizes an optical, three dimensional tracking system. The humerus was weighted to simulate the full mass of the upper extremity and stepper motors were connected to the insertion points of the anterior, middle and posterior divisions of the deltoid by Spectra® cord. Simulated active abduction in the scapular plane was performed using position closed-loop feedback control. The joint reaction force at the glenosphere was measured at 5° intervals from 30°–70°. A fourth stepper motor was then connected to the greater tuberosity with 2.73kg applied to simulate a LDT and the test was repeated. Five trials were performed under each condition. Four-factor ANOVA statistical analysis with Bonferroni correction and α = 0.05 was performed.

After simulated LDT the JRF demonstrated an increase in magnitude at abduction angles between 30° and 65° inclusive (p=0.033). The superiorly-directed shear force was significantly decreased as a result of the LDT between 45° and 70° (p< 0.0001). The compressive component of the JRF was increased for all abduction angles (p=0.025). The force required to achieve abduction increased for the middle deltoid (p=0.035) and anterior deltoid (p=0.036) for the simulated LDT condition at all abduction angles. The posterior deltoid force required for abduction decreased at all abduction angles (p=0.031).

In this model of reverse total shoulder arthroplasty concomitant transfer of latissimus dorsi decreased the superiorly-directed shear force. In addition to providing improved external rotation strength, these lower shear forces may have a protective effect on baseplate fixation by reducing the risk of failure in shear. This may provide additional justification for the transfer. Although superior shear was decreased, total JRF was increased as a result of an increase in the compressive component. Further investigation is needed to determine the potential gain in joint stability and whether the glenoid bone can support such elevated compressive forces. Additionally, the force required in the anterior and middle deltoid was increased after the LDT. This indicates the need for sufficient deltoid strength and rehabilitation.


H. Ike Y. Inaba N. Kobayashi N. Iwamoto T. Ishida Y. Yukizawa C. Aoki C. Hyonmin T. Saito

Periprosthetic bone loss is one of the major concerns in total hip arthroplasty (THA). Several studies have reported that bone mineral density (BMD) decreases after THA especially in the proximal femur. The phenomenon is explained as an adaptive remodeling response of bone tissue to a significant alteration of its stress environment. The purpose of this study was to evaluate the pattern of load transfer after stem implantation, and to compare the stress of finite element (FE) studies to BMD in the proximal femur after THA.

Forty-eight consecutive patients who received a primary cementless THA with implantation of the same femoral prosthesis (VerSys, Zimmer Inc, Warsaw, Idaho) between January 2007 to December 2007 were identified. Twenty-nine patients were excluded for administration of alendronate or alfacalcidol, and four patients were lost to follow-up or had incomplete computed tomography (CT) or dual-energy X-ray absorptiometry (DEXA) data. The remaining 15 patients formed the basis of this study. The average age of the patients at the time of THA was 64 years (range, 44 to 82 years). BMD were measured with DEXA at 1 week and 12 months after THA. Regions of interest (ROIs) were defined according to Gruen’s system (ROIs 1–7). FE models of the femur and stem were obtained from pre-and postoperative CT data by “Mechanical Finder (Research Center of Computational Mechanics Inc.)” that was a software to make FE models considering individual bone shape and density distribution. FE model of the femur consisted of approximately 600,000 elements and that of the stem consisted of 200,000 elements. The shaft was restrained and force was applied to the femoral head and directed within the coronal plane at 20° to the shaft axis. Stress distribution and strain energy density were analyzed and compared to DEXA data.

BMD maintained at 1 year after THA in ROI 3,4,5, and 6, where as BMD decreased in ROI 1,2, and 7 by 17%, 16%, and 26 %, respectively. This means that BMD decreased especially in the proximal femur at 1 year after THA. FE studies revealed that the stress and the strain energy density in ROI 3,4,5, and 6 were much higher than in ROI 1,2, and 7. It was suggested that high stress and strain energy density are contributed to maintenance of BMD in the femur at 1 year after THA.


R Russo M Ciccarelli L Vernaglia Lombardi F Cautiero G. Giudice

Aim: The treatment of the fractures to three and four fragments of the humerus still represents a challenge. The authors describe the surgical technique and results with a modular prosthesis that permits an anatomical reconstruction of the proximal humerus from the calcarside, that becomes the point reference of reconstruction with the “Puzzle-Pieces” technique.

Methods: From February 2000 to February 2007 41 patients were treated with modular prosthesis. They were 8 males and 33 females aged between 56 and 79 years. In 23 cases the interested shoulder has been the right, in 18 the left. All fractures were diagnosed with X-ray and CT-scan. The type of fracture includes: 20 fractures of four fragments, 15 pluri-fragmentary fractures, and 6 fracture\dislocations. At the follow-up we evaluated 26 patients.

Results: The functional results were evaluated in 26 patients by Constant score with a mean follow-up of 4 years. All the patients reviewed have executed a X-Ray, while in 18 cases we also have evaluated the reconstruction of the tuberosities with CT-scan. In one case there has been had a complete resorption of the tuberosities with insufficiency of rotator cuff. The mean of forward elevation was 132° Conclusion: The plant of a humeral pros-thesis for fractures is a very complex intervention. The technique, for modular prostheses it’s not very codified. Moreover the results from the Literature are inconstant in particular as to function of the shoulder, not predictable and often were it accompanied by complications.

The technique we described consists in the identification and reconstruction of the medial part of calcar that becomes “the thread conductor” for restoration of the height and the retrotorsion of the humeral head.


GP. Rinaldi F. Pace D. Capitani

The Gibson and Moore postero-lateral approach is one of the most often used in hip replacement. The advantage of this approach is an easy execution but it’s criticized because of its invasivity to muscletendinous tissues especially on extrarotators muscles and because of predisposition to posterior dislocation.

Since June 2003 we executed total hip replacements using a modified postero-lateral approach which allows to preserve the piriformis and quadratus femoris muscles and to detach just the conjoint tendon (gemelli and obturator internus). Articular capsule is preserved and it will be anatomically sutured at the end of the procedure as well as the conjoint tendon with two transossesous sutures. Piriformis and quadratus femoris muscles result untouched by this approach.

We have executed 500 surgeries with this modified approach.

We have used different stems (straight, anatomical, modular and short) and press fit cetabular cup with polyethylene or ceramic insert and we have always used 36 mm femoral heads when allowed by the cup dimensions. We have used any size both of stems and cups without limitation due to the surgical approach. The mean age is 61.8 y.o., 324 females and 176 males. Obese patients, hip dysplasia Crowe 3 and 4 and post traumatic arthrosis are exclusion factors for the execution of this approach. If possible we have maintained the capsulo-tendinous less invasivity. The BMI is not an excluding factor because it’s just the gluteus region that is an important factor to decide if to execute or not a less invasive approach.

Analyzing our 500 cases we didn’t have any case of malpositioning of the stem in varus or valgus (more than 5°) and considering acetabular cup we had the tendency to position it in valgus position (not more than 40°) in the first 20 cases.

No leg discrepancies more than 1 cm were observed.

Intra-operative blood loss have been reduced of about 30 % and 50% in the post-operative. All the patients were able to active hip mobilization within the first day after surgery with a mean range of motion of 0–70°. The patients were mobilized the first day after surgery and 80% of them were able to assisted walk within second day after surgery. The mean time of stay in hospital was 6.8 days.

After 4 weeks 98% of the patients were able to walk without crutches.

One case of deep infection were evaluated and then solved with surgical debridement; no wound dehiscence. We had 1 case of anterior hip dislocation in dysplastic arthrosis due to a technical mistake. In 1 case we had femoral nerve palsy, then solved, probably because of anterior retractor malpositioning. We had 5 cases of piriformis muscle contracture without sciatic nerve palsy, then solved. We think that for total hip replacement this conservative postero-lateral approach, thanks to capsuletendinous modification we have adopted, could be considered an anatomical approach, which doesn’t present more dislocation risks compared to other approaches to the hip also thanks to the introduction of 36 mm femoral head that gives more stability and proprioceptiveness. Besides this approach gives the possibility of a shorter rehabilitation as seen above and it could be consider optimal for total hip replacement.


R. Accetta A. Meersseman L. Monti F. Anasetti G. Mineo

In this report a novel surgical treatment of proximal humerus fractures with shoulder hemiarthroplasty through an anterolateral acromial approach is presented. This access allows a drastic reduction of the risk of iatrogenic neurovascular complications and was developed to allow less invasive treatment of proximal humerus fractures with an easy control of the tuberosities which are often dislocated. Furthermore, this access allows the conservation of the anatomical integrity of the rotator cuff muscle which is fundamental in older patients. After removal of the humeral head, by this antero-lateral approach a better visibility of glenoid cavity is achieved thus allowing a more correct prosthesis components placement and a easier fixation of the tuberosity around the prosthesis using strong non-absorbable suture.

Over a 2-years period, 24 patients (age 68.9, range 53–83, 17 females and 7 males) with either displaced 4-parts fractures, according to Neer classification, or fracturedislocations of the humeral proximal third, were surgically treated trought a shoulder hemiarthroplasty with direct antero-lateral acromial approach. Clinical and functional assessments were performed at 3, 6, 12, and 18 months including the determination of the Constant Score, the radiographic assessment in an antero-posterior and axillary view of the humerus, a photographic documentation of the injured shoulder function as compared with the non-injured extremity and the assessment of the upper limb motion with a motion analysis system.

An increase in mean Constant Score and ranges of motion was observed over the follow-up-period. At 12-months follow-up the Constant Score was 62.2 points (range 41–91) out of a total of 100. Patients at 12 months showed a mean active flexion of the shoulder in the sagittal plane of 45.8 degrees (range 19.1–89.4); the mean active abduction was 49.4 degrees (range 26.1–90.8) with forearm turned down and 57.1 degrees (range 16.7–119.2) with forearm turned up; the range of rotation was 30.9 degrees (range 26.2–35.6). Nevertheless, all patients were able to perform the activity with a relatively pain-free shoulder.

The results obtained in the present study are comparable with the literature data, where other surgical approaches were used. Due to its conservative features, the presented surgical approach may represent a good alternative in shoulder hemiarthroplasty.


J.F. Cazeneuve Y. Hasssan A. Hilaneh F. Kermad A. Brunel

Synthesis and hemi-prosthesis give well known radiological results for acute proximal complex humeral fractures in elderly population. We wanted to expose the radiological outcome of the reverse concept in this indication.

From 1993 to 2008, forty four DELTA III were implanted for thirty three three-part and four-part displacements and eleven fracture-dislocations, in 3 males for 41 females, with an average age of seventy five years. The results were estimated with AP and LAMY profile Xrays.

Because of ten deceases and three moving, thirty one cases were reviewed with a mean follow-up of 6.3 years, range 1 to 15. The radiographs showed : two 2-mm thick borders on the glenoid at four and eight years with a scapular notch at 11 years and an aseptic loosening of the base plate at 12 years with a broken polar inferior screw. The patient underwent an easy surgical revision because of a fair bone stock. There was no wear of the polyethylene.

According to the NEROT classification, nineteen inferior scapular notches were observed with a mean occurrence time of 4.6 years. The seven type-1 notches appeared at a mean of 2 years and the five type-2 notches at a mean of 4.3 years. We observed four type-3 notches which reached the inferior screw at 5,6,7 and 8 years, and three type-4 notches which extended beyond the inferior screw at 6,7 and 8 year follow-up, respectively. There seem to be two distinct patters of notches: mechanical, stable proximal humeral bone loss because of an impingement between the humeral component and the inferior scapular pillar and biological, progressive in size, evolving over time with proximal humeral bone loss because of polyethylene disease; the longer the follow-up, the more severe the notch. Fourteen inferior spurs, stable after emergence, were reported with a mean occurrence time of 2.5 years range 1 to 6 years. One joint ossification occurred at 6 months and was stable at 6 year follow-up. The humeral results consisted in five medial (5,6,710, and 11 years) proximal bone looses and three bone-cement interface medial borders on the two thirds of the height of the stem at a mean follow-up of 5 years. In these eight cases, there was a notch associated. We reported one case of septic humeral loosening at 2 year follow-up.

For acute proximal humeral complex fractures in elderly population, when re-fixation of the tubercles on the classical orthopaedics devices is impossible, the use of a DELTA III prosthesis shows, with a mean follow-up of 6.3 years, worrying images in 70% of the cases.

These images are on the glenoid in 70% of the cases, appeared before seven years in 86% and are progressive in 50% of the cases. But, we have only one re-intervention for an aseptic loosening of the base plate at a twelve year evolution. New developments in design and bearing surfaces and a more long term results will probably provide more durable utilization of the reverse concept in this indication.


C.J. Wang J.M. Chen S.L. Hsu T. Wong W.Y. Chou

This study compared the functional outcomes of total hip arthroplasty (THA) in one hip and extracorporeal shockwave (ESWT) in the other hip in patients with bilateral hip necrosis.

Seventeen patients with bilateral hip necrosis were treated with THA for late stage ONFH in one hip and ESWT for early lesion in the other hip. In THA, only one type of prosthesis was used and all components were cementless. In EWST, each hip received 6000 shocks at 28 Kv (equivalent to 0.62 mJ/mm2 energy flux density) in a single session. The evaluations included pain score, Harris hip score, radiographs and MR images at 6 and 12 months and then yearly.

Significant improvements in pain score and Harris hip score were noted after treatment in both hips. However, the magnitudes of improvement showed significant differences between the two sides favoring the ESWT side. On subjective assessment, 13 patients rated ESWT better than THA; 4 patients reported comparable results of THA and ESWT, and none graded THA better than ESWT. In THA side, abnormal radiographs were noted in 47% (8 of 17) including component mal-position, nonprogressive radiolucency, and suspected component loosening. In ESWT side, significant reduction of bone marrow edema and a trend of decrease in the size of the lesion were observed after treatment.

ESWT and THA are effective for early and late stages of ONFH respectively.

However, better functional outcomes were observed in ESWT-treated hips than hips treated with THA in patients with bilateral hip disease in short-term.


T. Lovell W. Hozack S. Kreuzer P. Merritt M. Nogler L. Puri T. Wuestemann A. Bastian

The current decade has seen a marked rise in popularity of minimally invasive hip replacement, done through a variety of surgical approaches. A specific downside to the direct anterior approach includes the significant difficulty getting a “straight shot” down the femoral canal for either straight, nonflexible reaming or broaching as with standard approaches. Improper alignment in the femoral canal can lead to sub-optimal load transfer and thus compromised fixation. The femoral broach and stem insertion path for this approach is best described as a curved one, rather than the typical straight path. Some femoral components appear to be more suitable to this technique due to their geometries. The purpose of the study was to describe the effects that the single geometric parameter, stem length, has on its insertion path into the femoral canal. Due to the potential introduction of human error associated with repetitively performing a specific motion, both a physical study and a computer generated analysis were conducted.

For the physical portion of the study, a femoral implant body of generic fit and fill geometry was designed and manufactured. The length of the stem was varied from 40 mm to 100 mm in 10 mm increments. A medium sized synthetic femur (Sawbones, Pacific Labs, Seattle, WA) was machined to match the volume of the full length stem. The insertion path constraints were defined such that the stem had to maintain the greatest allowable insertion angle while still making contact on both the medial and lateral side of the canal during translation in the X direction. To reduce the variability in applying the constraints, a single author conducted the insertion procedure for each length stem while the path was videotaped from a fixed position directly in front of the setup. The most proximal lateral point of the stem was tracked through the insertion path and the X, Y coordinates were recorded at a frequency of 2 FPS. The area under this curve, referred to as the minimum insertion area (MIA), was calculated.

For the computer generated portion of the study, a CAD model of the standard length Omnifit® (Stryker Orthopaedics) was utilized. The stem was modified to create 5 additional models where the length was progressively shortened to 65%, 55%, 45%, 35%, and 25% of original length or 91mm, 77mm, 63mm, 49mm, and 35mm respectively. The femur was created from a solidified mesh of a computed tomography (CT) scan with the canal virtually broached for a full length stem. The models were each virtually assembled within the femoral canal with the similar constraints as the physical study. Again, the most proximal lateral point of the stem was tracked through the insertion path with the coordinates recorded and the MIA was calculated.

There was a non-linear relationship between stem length and the MIA with the rate of change decreasing as the stem length decreased. That is, the greatest decrease in MIA was between the standard length and next longest length in the computer simulation. It was noted that marked change in MIA began to subside between the 77mm and 63mm stems and continued this trend of having less influence onward through to the shorter lengths. Although the results of the physical study showed a higher variability than the computer generated portion, it does confirm the results of the computer generated study.

Minimizing the trauma associated with THR has led most of the above authors to the direct anterior approach. However, the femoral broach and stem insertion path is best described as a curved one, rather than the typical straight path used in other approaches. This curved insertion path also has benefits for other approaches since the broaches and stem can be kept away from the abductors, minimizing the potential injury to them. Shorter stem length makes this curved insertion path easier to perform. This is the first study to describe the effect that stem length has on its insertion path into the femoral canal. As expected, the physical portion of the study showed more variability than the computer generated portion. However, the physical and computer studies correlated well, with shorter stem lengths clearly allowing a more curved insertion path. The improvement tapered off in stem lengths below 63mm. This length correlates well with the other attempts at a shorter stem. This study provides quantitative data to help with shorter stem design and possible computer navigated insertion paths.


S. Kamada M. Naito Y. Nakamura T. Teratani A. Takeyama H. Karashima K. Kinoshita N. Kashima Y. Tanaka K. Ida D. Kuroda

The Mayo-Stem is short and tapered in the anteroposterior and mediolateral directions, designed to enhance early fixation through multiple point contact in the proximal medullary cavity. The purpose of this study was to investigate the clinical and radiographic results of total hip arthroplasty (THA) using this short stem in younger patients.

A total of 97 cementless THAs using this short stem were investigated. The length of the stem used ranged from 90mm to 110 mm. The average age of the patients at the time of surgery was 50.9 years (33–64 years). The average follow-up period was 64 months (38–108 months).

The Harris hip score was used for clinical evaluation. The valgus angles of the stems and the changes in radiographic findings around the stems after surgery were investigated on the AP radiographs of hip.

The average Harris hip score was 52.0 points pre-operatively and 93.9 points at the latest follow-up. An intraoperative femoral fissure fracture of the proximal femur occurred in 15 hips (15.4%), which were treated by circlage wires. The average valgus angle of the stem was 3.5° (range: −6°–18°). The development of bone trabeculae was seen around the curve of the stem (Gruen zones 3 and 5) in 79.4 % of hips one year after surgery. A radiolucent line was found on the lateral side of the stem (Gruen zones 1, 2, and 3) in 13.4 % of hips, which occurred in connection with the development of bone trabeculae. Subsidence of the stems (> 2mm) was seen in three hips in which intraoperative femoral fissure fracture had not occurred. These hips did not get the development of bone trabeculae. In two hips of the three hips, the valgus angles of the stems were 15° and 17° respectively. In the case of the third hip, the stem was small to the proximal femur.

Overall the clinical result of THA using a short-stem was basically gratifying.

The development of bone trabeculae, the stem size to the proximal femur and the stem position were important factors for the fixation of stem. Intraoperative fissure fracture treated by circlage wires and radiolucent lines with the development of bone trabeculae did not affect the fixation of stem.


C.J. Wang F.S. Wang J.Y Ko S.Y. Huang J.M. Chen

The effect of shockwave in osteonecrosis of the femoral head (ONFH) is poorly understood. The purpose of this study was to investigate the regeneration effects of shockwave in ONFH.

This study consisted of 14 femoral heads from 14 patients undergoing total hip arthroplasty for ONFH. Seven patients with seven hips who received shockwave prior to surgery were designated as the study group, whereas, seven patients with seven hips who did not receive shockwave were assigned to the control group. Both groups showed similar demographic characteristics. The femoral heads were investigated with histopathological examination and immunohistochemical analysis with von Willebrand factor (vWF), VEGF, platelet endothelial cell adhesion molecule-1 (PECAM-1) also referred to as (CD 31) and vascular cell adhesion molecule (VCAM) for angiogenesis, and with proliferation cell nuclear antigen (PCNA), Dickkopf-1 (DKK1) and Winless 3a (Wnt 3) for bone remodelling and regeneration.

In histopathological examination, the study group showed significantly more viable bone and less necrotic bone, higher cell concentration and more cell activities including phagocytosis than the control group. In immunohistochemical analysis, the study group showed significant increases in vWF (P< 0.01), VEGF (P¼0.0012) and CD 31 (P¼0.0023), Wnt3 (P¼0.008) and PCNA (P¼0.0011), and decreases in VCAM (P¼0.0013) and DKK1 (P¼0.0007) than the control group.

Shockwave treatment significantly promotes angiogenesis and bone remodelling than the control. It appears that application of shockwave results in regeneration effects in hips with ONFH.


Shunji Nakano Hirofumi Kosaka Masaru Nakamura Takashi Chikawa Yugi Taoka Tateaki Shimakawa Akira Minato Takaaki Ikata Megumi Sogame

Objective: The number of hip prostheses replacement surgeries particularly in elder people with osteoporosis, has been increasing every year; given this scenario, treatment of postoperative periprosthetic femoral fracture has become a critical problem. Osteosynthesis is generally selected as the procedure of choice for the surgical treatment of fractures, provided the stem prostheses do not show loosening. Stable fixation of periprosthetic femoral fracture is difficult in the elderly because they have osteoporotic bone and most of the intramedullary space is occupied by the metal stem implanted in the proximal femoral shaft. With a view to solving this problem, we developed a new surgical treatment for postoperative periprosthetic femoral fracture; this procedure use a trimming intramedullary nail, which we have termed “docking nail.” [Materials] The subjects were 3 patients (81, 75 and 76 years old) who had suffered a femoral shaft fracture around the femoral prosthesis after total hip replacement; in all 3 patients, there was no apparent sign of loosening of the stem prosthesis. The implanted stem was cemented in one patient and uncemented in the other two.

Method: Using information on the size and shape of the stem prosthesis as well as information from the pre-operative radiographs, we cut the docking nail till the proper length was achieved and trimmed it to suit the cutting site in order to ensure that it was compatible with tip of the stem. We then performed osteosynthesis using instruments of an ordinary supracondylar type intramedullary nail. In cases where it was difficult to reposition or where it was necessary to remove excessive cement and bone from around the tip of stem and graft a free bone in the bony defect, we exposed the fracture site as minimally as possible. The major difference between our procedure and the conventional procedure is that in our procedure, the docking nail is connected to the tip of the implanted stem to ensure proper alignment. Postoperative immobilization was not used in any of the patients except for the 81-year-old patient, for whom partial weight-bearing was allowed at 4 weeks, and full weight bearing at 12 weeks. The mean follow up period was 22 months (range, 6–48 months).

Result: Within 3 months, bony union with good alignment was achieved in all 3 patients without malunion or infection. The clinical and radiographic examinations conducted during the follow-up period showed good results.

Conclusion: The advantages of this method are that it is less invasive and simple compared to the conventional methods. Its only disadvantage is that it requires considerable, preoperative planning and minor trimming of the nail. Although this series is small, we think that this new treatment can be recommended and will be beneficial for treating periprosthetic femoral fractures without a loose stem. However, these preliminary findings need to be confirmed by further investigations.


Dr. Ashok Rajgopal

We undertook a study of 52 knees in 34 patients who underwent a cruciate retaining total knee arthroplasty (TKA) for severely deformed knees. At an average follow up of 12 years the knees were evaluated clinically and radiologically by means of stress radiographs and Magnetic Resonance Imaging (MRI) to assess the functional status of the posterior cruciate ligament (PCL). The knee scores showed a consistent and sustained improvement over the pre-operative levels. Stress radiographs did not show any posterior translation of the tibia. In 43 knees an intact PCL was visualized on MRI scans.

These observations suggest that the PCL is present at long term review even in knees that underwent arthroplasty for severe deformities.


A. Croce M. Ometti P. Dworschak

The use of neck modular adapter is a relative new solution for hip revision arthroplasty. This device assure a lot of advantages for the orthopaedic surgeon because Bioball can be use in different situations in order to solve different complications: hip prosthesis dislocation, correction of length (up to +21mm), save an old stem not mobilized, reduction of operation length.

The hip prosthesis dislocation, in spite of the continuous progress of implants’ materials and design, is still an actual event in the orthopaedic clinical practice, both after total hip replacement or a endoprosthesis. Furthermore, dislocation has an important social-economic impact because of a protracted hospitalization and rehabilitation and elevated costs of an eventual revision. Although using heads with a diameter larger than 28 mm we obtain virtually a greater range of motion, with a contemporary increase of degree necessary to cause the head-neck impingement, the risck of dislocation hasn’t a significant increase using head with a diameter of 22 mm.

Neck modular adapters (Bioball) allow to correct easily the biomechanics parameters of the dislocated prosthesic joint, avoiding the revision of the stem. Other indications for the use of the neck modular adapter are total hip replacement and intraoperatory correction of the limb length. Vantages are the possibilty to obtain a great range of motion through a small thickness of the 12/14 adapter, the possibility to extend the limb length up to 21 mm and to use ceramic heads during revisions, because the combination head/neck has a tribological unweared surface. In fact, in normal conditions, if the stem is not mobilizated, the use of ceramic head is rash; the Bioball adapter, instead, can be used with a old stem, so we can set a ceramic head. Every stem with a Biolox cone can be combined with a metal or ceramic head up to the 5XL size (+21 mm) through a Bioball adapter; in this way the cup is not removed.

We have two kinds of neck modular adapters: 12/14 allow both to extend the neck and to correct the offset, and 14/16 that allow to extend only the neck, because of the largest diameter of the prosthesic neck and the small thickness of the adapter. For these neck modular adapters exist different sizes, from M to 5XL (+21mm). Recently to these two types of Bioball were introduced also solutions for special stems (like for Exeter, ABG I, ABGII, PCA and others) We have also proving heads and necks. The proving and definitive heads have to be of the Bioball system because these are inserted on a modular neck with a no-standard diameter.

In the common practice the use of these adaptors has not to be considered as a routinary procedure, but have to be taken in consideration as a valid aid for orthopaedic surgeon to quickly and less invasively, solve technically demanding procedures with a real benefit for high-surgical risk patients.


Wang Huijuan Sheng Lin Weng Xisheng

Resection of the distal femur to properly fit the prosthetic component is a crucial step for prosthesis alignment during TKA. In this study, we development a new integrative(Five-In-One, FIO) femur resection method, which performs distal femoral resection in one procedure instead of the standard five cutting steps. The accuracy and operating time are comparable to the conventional cutting methods using foam bone model experimentation and in 9 patients.

In vitro comparison: Uniformly-sized foam bone femur models were used in this study. New five-in-one cutting devices and conventional cutting devices of the same prosthetic size of #44 were installed and resection of the distal femur by five experienced orthopaedic surgeons. Each surgeon performed five cases with each device. Then a femoral prosthesis (#44) was installed on each cut femur mode and anterior-posterior and lateral X-ray radiographs were taken. The angles facet length and distance between anterior and posterior oblique facets were then measured with goniometer and vernier calliper. The corresponding angles from a standard femoral prosthesis (#44) were also measured. The angular difference between the resection femur and prosthesis was calculated and named Angular Deviation. The valgus angle and anteversion angle were measured on anteriorposterior and lateral X-ray radiographs respectively. The mean value from the five measurements obtained from each surgeon using the same cutting method was used for the comparison of the modified and standard resection model. The operating time of each cutting procedure was recorded. students’t-tests were used for the statistical analysis.

In vivo following up: 9 patients with use of the five-in-one cutting instrument and the Deluxe prosthesis have been evaluated during operating, and followed up for at least one year. Operating time were recorded and HSS clinical and functional scoring systems before the surgery, three months and one year after surgery.

The angular deviation of the new FIO Cutting Device was significantly less than the conventional device in all four anatomic measurements (p < 0.05). The distance deviation in the FIO group was also significantly less in the FIO group compared to the conventional procedure (p < 0.05). The average valgus angle and anteversion angle of the five-in-one cutting device which were measured on anterior-posterior and lateral X-ray radiographs respectively were 6.86° and 3.02° respectively. They were not significantly different when compared with the data of the conventional cutting device, which were 6.56o and 3.06o respectively. The mean of the cutting time of the five-in-one device was 9.70 minutes, which was significantly less than the conventional cutting device which was 21.84 minutes averaged (p < 0.05).

Our data demonstrated that the angular accuracy of the distal femoral resection with the newly Five-in-one technique was greatly improved compared to the conventional cutting method. With the use of the new technique, operative time was also shortened over two folds compared to the conventional method. We conclude that the new five-in-one cutting device is more accurate and shorten operating time compared with the conventional device in the vitro study.

The mean HSS score before surgery was 48.69, 84.7 three months after surgery, and 85.6 at one year after surgery. The survivorship was 100% of patients.


D. K. Bae K. H. Yoon S. J. Song M.C. Shin J.H. Noh M.J. Park H.J. Cho I.H. Choi

In conventional high tibial osteotomy it is difficult to obtain the ideal correction angle consistently and there is high variability of postoperative alignment. We assessed the reliability, accuracy and variability of closed wedge high tibial osteotomy using computer-assisted surgery compared to the conventional technique. Fifty closed wedge HTO procedures were performed and analysed between July 2005 and July 2006, using the CT-free navigation system(Vector Vision® version 1.1, Brain-LAB, Heimstetten, Germany) for medial compartment osteoarthritis of the knee and fifty knee operations using conventional closed-wedge HTO, performed between 1994 and 2006, were retrospectively reviewed as a control group. The mean age was 59.4 years for the navigation group and 60.7 years for the conventional group. In the navigation group, the mean mechanical axis (MA) before osteotomy was varus 8.2°, and the mean MA after the fixation was valgus 3.6°. On the radiographs, the mean preoperative MA was varus 7.3°, and the mean postoperative MA was valgus 2.1°. In the conventional group, the mean MA was varus 10.6° preoperatively and valgus 0.1° postoperatively via the radiograph. The mean preoperative posterior slope angle (PSA) was 11.0°, which decreased to 9.0° in the navigation group. The mean preoperative PSA was 10.4°, which decreased to 6.4° in the conventional group(p = 0.000). There was a positive correlation between measured data taken under navigation and by radiographs(r > 0.3, P < 0.05). The mean correction angle was significantly more accurate in the navigation group(p < 0.002). The variability of the correction was significantly lower in the navigation group (2.3° versus 3.7°, p = 0.012), and the distribution of MA was also narrower in the navigated group.

We concluded that navigation provides reliable real-time intraoperative information and may increase accuracy, and improve the precision of closed-wedge HTO.


M. A. Rosa A. Pisani G. Maccauro G. Arrabito

Aims: The innovative surgical procedure of humeral resurfacing emiarthroplasty is currently used for the treatment of younger patients, in need of a bone-preserving implant, affected by primary gleno-humeral osteoarthritis and rheumatoid arthritis, secondary degenerative joint disease, post-traumatic arthritis or mal-unions of the humeral head, loss of articular cartilage, joint incongruity and stiffness, avascular osteonecrosis of the humeral head, combined loss of the gleno-humeral joint surface and rotator cuff loss of function and pain unresponsive to nonoperative measures. Published reports have indicated a large variation in the benefits of this procedure. The aim of this study is to analyse the clinical results obtained by the authors in a preliminary report of a two-years experience in the surgical actuation of this procedure, that represents one of the most innovative options in the field of the shoulder arthroplasty.

Materials and Methods: The authors report the outcomes of their experience in humeral head surface replacement emiarthroplasty. In the last two years 25 selected patients have been treated according to the surgical implantation of the “bone sparing” Global Cap conservative anatomic prosthesis (DePuy). The mean age of the patients was 52 years (range, 34 to 76 years). They have been followed for a mean of 8 months, (range, 4 to 16 months).

Preoperative diagnoses were: osteoarthritis, rheumatoid arthritis, psoriasic arthritis, osteonecrosis and post traumatic arthritis. 8 patients underwent contextual cuff tear repair.

Results: Constant score for the whole group improved from a mean preoperative score of 22 to 60 at the last follow-up. Periprosthetic osteolisys was seen in 3 cases. One case of stiffness required narcosis mobilization at 5 months after surgery. Our results are comparable to those obtained with others modern R.R.H. and are similar to Copeland’s own series.

Conclusions: The preliminary results of our study show how some pre-operative factors appear to influence the functional improvement and the personal satisfaction rate of the patients after humeral resurfacing emiarthroplasty. The most important are represented by: the presence of erosions in the glenoid cartilage, possible previous shoulder surgery and associated cuff tears. The gender of the patients doesn’t appear a discriminating factor. The age appears to influence only boundedly the clinical post-operative outcomes. In our opinion, the initial diagnoses is determinant: patients affected by systemic pathology, like rheumatoid arthritis, or by cuff tear obtain the least functional improvement and satisfaction; on the contrary, patients affected by primary and secondary degenerative joint diseases, post-traumatic cartilage lesions and avascular osteonecrosis of the humeral head obtain better results.


PJ Tong SX Zhang HT Jin L Chen WF Ji J Li

The purpose of this study was to analyze the long-term effect of arterial perfusion of drugs and bone marrow stromal cells (bMSCs) on osteonecrosis of femoral head (ONFH). From Jan 1997 to Mar 2004, one hundred and seventeen patients with ONFH were consecutively enrolled to receive a digital subtraction angiography (DSA) in arteriae circumflexa femoris medialis and arteriae circumflexa femoris lateralis. In DSA, a dosage of drugs (urokinase, salvia injection, and tetramethylpyrazine) and autologous bMSCs or only the drugs were perfused into the arteries. The morphological changes of the arteries in DSA after perfusion were recorded. Symptoms radiographs, and the Harris hip-rating score were determined preoperatively and at each follow-up examination at one month, six months, one year, 2 years and 5 years after the treatment. 83 patients were followed up for more than five years. The median follow-up period was 7.9 years.

After the drugs had been perfuse, the arteries became thicker, and more than 2 branches appeared in DSA. Five years after the operation, the Harris hip score of 32 patients (38 hips) treated by arterial perfusion of simplex drugs (group A) increased from 59.24±5.28 to 71.80±6.37 (p< 0.01), and the excellent and good rate of centesimal evaluation was 57.9%. The Harris hip score of 51 patients (59 hips) treated by arterial perfusion of drugs and autologous bMSCs (group B) increased from 59.52±4.85 to 78.29±6.05 (p< 0.01), and the excellent and good rate was 78.0% which was significantly higher than that of group A (p=0.035). Since two years after operation, the Harris hip score of group A was significantly higher than that of group B (p< 0.01).

Among the patients in group B, the rate of excellent and good in early stages (˜,˜ a and ˜ b according to Ficat classifying, 50 hips) was 84.0%, which was better than the rate in the terminal stage (Ficat III, 9 hips, the excellent and good rate was 44.4%)(p = 0.028), and the rate of excellent and good in low age group (< 40 years, 33 hips) was also better than that in high age group (≥ 40 years, 26 hips)(p=0.038).

We conclude that arterial perfusion of drugs and autologous bMSCs treating osteonecrosis of femoral head is safe and effective. The long-term therapeutic effect is more satisfactory than that of simplex arterial perfusion of drugs.


J. Fuchs W. Shields W. Schmidt I. Liepins J. Racanelli

Introduction: Uncemented proximally filling porous-coated femoral components must be designed with an optimal level of press-fit. Excessive press-fit yields higher femoral stress which can result in periprosthetic femoral fracture (PPFx), whereas insufficient femoral stress can lead to a lack of initial mechanical stability, which “is necessary to achieve bone ingrowth into the porous surface” (Manley P.A. et. al., J Arthroplasty10:63–73, 1995) of the implant. An optimal press-fit design should also provide an accurate and repeatable femoral stem seating height in all patients.

A battery of cadaveric tests, physical “bench-top” tests, and finite element analyses (FEA) should be used in order to both quantitatively and qualitatively optimize a femoral press-fit design. In this study, a method is proposed to quantitatively rank candidate press-fit stem designs relative to successful predicates based on stem seating height and PPFx risk by recreating impact loading applied during surgery through a controlled “bench-top” model.

Methods: Three press fit candidate designs A, B & C and two clinically successful predicate proximal fit and fill stems (Secur-Fit™ Max (Fit & Fill 1) and Meridian® TMZF® (Fit & Fill 2), Stryker, Mahwah NJ) were evaluated. Five foam cortical shell Sawbones® femur samples (Item# 1130, Pacific Research Laboratories, Inc., Vashon, WA) were prepared for each press-fit design. A stem impactor was attached to the stem and then the stem was hand inserted in the femur. Then the construct was mounted in the drop tower using a vice and initial drop height was set to generate approximately 5500 N of impaction force when fully seated. Each stem was serially impacted until stable then step loaded until PPFx occurred. The height above/below the medial resection plane was measured after each impaction.

Results: All press-fit designs had an initial stable seating height within the desired range without causing PPFx, using an average impaction load of 5341 N. All of the press-fit designs required, on average, roughly a 200% increase in impact load (10925 N) to cause PPFx. The press-fit deign which ranked first based on seating height accuracy, defined as the design closest to zero at stable, was Design C at −0.02 mm countersunk. Design A with a standard deviation of 0.09 mm ranked first for repeatability, defined as the design with the smallest standard deviation at stable. Finally the press-fit design which ranked first for lowest PPFx risk, defined as the design that is most countersunk prior to PPFx, was Fit & Fill 1 at 6.30 mm countersunk.

Discussion: This controlled “bench-top” impact loading model successfully showed that it can quantitatively evaluate stem seating height and PPFx risk for several different femoral press-fit designs. In order to determine the optimal design, each press-fit design was ranked with equal weight given to seating height and fracture risk. Using this test method one design alternative, press-fit Design C, ranked first as the optimal combination of seating height accuracy and consistency with a low risk of PPFx. A limitation of this impaction model is that it does not directly predict PPFx rate, it only quantifies risk of fracture. Another limitation is that this model does not simulate all of the variably that is inherent to actual patient bone types. This test is one step in a battery of tests, including cadaveric evaluation and FEA, which should be used in order to optimize a femoral press-fit design.


K. Gokaraju B.G.I. Spiegelberg M.T.R. Parratt J. Miles S.R. Cannon T.W.R. Briggs

There is limited literature available on the use of metal prosthetic replacements for the treatment of non-traumatic lesions of the proximal radius. This study discusses the implant survivorship and the functional outcome of the elbow following insertion of metal proximal radius endoprostheses performed at the Royal National Orthopaedic Hospital.

We present a series of six patients treated with endoprosthetic reconstruction of the proximal radius following resection of non-traumatic pathologies. The patients included four females and two males, with a mean age of 39 years at the time of surgery. Their diagnoses included Ewing’s sarcoma, chondroblastoma, benign fibrous histiocytoma, radio-ulna synostosis and renal carcinoma metastases in two patients. Follow-up extended to 192 months with a mean of 76 months. During this time there were no complications with the prostheses, the most recent radiographs demonstrated secure fixation of the implants and none required revision. One patient developed posterior interosseuous nerve neuropraxia following surgery, which partially recovered, and another patient passed away as a result of disseminated metastatic renal cell carcinoma which was present preoperatively.

The patient with radio-ulna synostosis had a 25° fixed flexion deformity of the elbow post-operatively but good flexion, supination and pronation. All other patients had full ranges of movement at the elbow.

Functional scores were assessed using the Mayo Elbow Performance Score with patients achieving a mean score of 86 out of 100.

The results of the use of proximal radial endoprostheses for treatment of non-traumatic lesions are encouraging with regards to survivorship of the implant and functional outcome of the elbow.


M. Kawasaki Y. Tamai T. Fujibayashi T. Takemoto

Total Hip Arthroplaty (THA) using posterior approach(PA) that resect muscle have done from September, 2005 to August, 2006, but, for the purpose of a lower invasive surgery, we changed to THA using direct anterior approach(DAA) that preserve muscle from September, 2006. The purpose of this study was to compare the inflammation degree and clinical results of MIS-THA using PA with that of MIS-THA using DAA.

From September 2005 to May 2008,73 hips in 69 patients were treated with consecutive primary cement-less MIS THA. The breakdown of the patients was DAA, 51 hips, and PA, 22. The average age at operation was 66 years and 58 years. The average followup after primary THA was 1.5 years and 2.8 years. The sex ratio (M/F) was DAA 2/44, and PL 6/15. For the inflammation degree, CRP at the seventh day and 14 day after surgery of DAA was significantly lower than those of PA (p< 0.01). WBC of the seventh day of DAA was significantly lower than that of PA.CPK on DAA at the first was significantly lower than that of PL (p< 0.01), and CPK of PL took time for a long time to decrease to the level before the operation compared with DAA. For clinical results, there were no significant difference operative time, blood loss volume and complication in DAA and PA. No significant differences in the HHS at the final follow up were observed between DAA and PA. In the radiographic assessment, there was no significant difference in neutral position of stem of DAA(46hips) and PA (18hips), and there was no significant difference in abduction angle of socket in DAA(average 45°) and PA (47°). The day of SLR possibility was significantly earlier DAA (average 4 day) than PA (7). No significant differences in hospital stay were observed between DAA (average 21 days) and PA (26).

In the current study, there was thought that DAA was lower inflammation degree than PA, because normalization of CRP after surgery in DAA was significantly early in comparison with PA, and CPK of the first day after surgery was significantly lower in DAA than in PA. In the clinical assessment, the day of SLR possibility only was significantly earlier in DAA than in PA. This may imply muscle recovery of DAA is more rapid than that of PA. In the future, DAA will help to the further early rehabilitation and the early hospital discharge.


Full Access
Joseph F. Fetto P. Walker

Recent trends in surgical techniques for THR, i.e. MIS and anterior approaches, have spawned an interest in and possible need for shorter femoral prostheses. Although, previously published clinical investigations with custom short stems have reported very encouraging results (Walker, et al, 1,2), the transition to off-the-shelf (OTS) versions of shorter length prostheses has not met with the same degree of success. Early reports with OTS devices have documented unacceptably high and significant incidences of implant instability, migration, mechanical/aseptic failure, and technical difficulty in achieving reproducible implantation outcomes. They have highlighted the absolute need for a better understanding of the consequences of changes in implant design as well as for improvements in instrumentation and surgeon training.

Several basic questions must be addressed. First, what is the purpose of a stem? Second, can stem length be reduced and if so by how much can this be safely done. Third, what are the effects of stem shortening and are there other design criteria which must take on greater importance in the absence of a stem to protect against implant failure.

To examine these questions a testing rig was constructed which attempts to simulate the in vivo loading situation of a hip, fig.1(Walker, et, al.). Fresh cadaveric femora were tested with the femora intact and then with femoral components of varying stem length implanted to examine the distribution of stresses within the femur under increasing loads as a function of stem length. This was correlated with observations of prospective DEXA measurement of proximal femoral bone mass and implant migration following THR(Leali, 3).

Our studies indicated that a stem is not an absolute requirement in order to achieve a well functioning, stable implant. However in order to reduce the possibility of mechanical failure a reduced stem or stemless implant absolutely must have, inherent to its design, a provision for sufficient contact with both the medial and lateral proximal metaphyseal femur. As well it must also have a flat posterior surface parallel to, and in contact with, the posterior surface of the proximal femoral metaphysis. These conditions will provide support against distal migration as well as bending moments in the A/P plane. As a consequence of this latter condition, appropriate anteversion must be achieved in the neck region of the prosthesis and not by rotation of the implant within the proximal metaphyseal cavity of the femur.

In conclusion, this study demonstrates that simply reducing the length of an existing implant to accommodate changes in surgical techniques may not be a reasonable or safe design change. Such shortened versions of existing stem designs should undergo rigorously in vitro testing before being released for implantation.


N. Kitamura K. Arakaki K. Susuda E Kondo K. Yasuda

Introduction: While plain radiographs are the clinical standard for routine follow-up after total knee arthroplasty (TKA), periprosthetic osteolysis can be difficult to identify on radiographs because it is often obscured by the metallic prosthesis. This study sought to evaluate the pattern and size of periprosthtic osteolytic lesions after TKA in patients with rheumatoid arthritis using multi-detector computed tomography (MDCT).

Methods: We evaluated 25 primary cemented alumina-ceramic TKAs (LFA-I, Kyocera) using minimum 10-year CT scans. All TKAs had an alumina-ceramic femoral component, a titanium tibial baseplate with a poly-ethylene insert, and a polyethylene patella component, which had been fixed with cement. The average age at the time of surgery was 54.1 years. The average time interval between surgery and the computed tomography scan was 12.6 years. None of the patients in this study documented periprosthetic infection or had undergone bone grafting.

Results: The MDCT detected 31 lesions in 12 knees: 23 femoral and 8 tibial lesions.

All lesions occurred around the prosthetic rim, and the mean size of osteolysis per knee was 2.1 +/−1.5 cc (range, 0.4–4.7 cc). Only seven lesions in 6 knees were diagnosed as osteolysis on plain radiographs: 2 lesions at anterior femoral condyle and 5 lesions at tibial condyles. None of the lesions around the posterior condylar flanges detected on CT was identified on plain radiographs. None of the implants showed radiographic loosening or required reoperation.

Discussion: As the alumina-ceramic TKA allowed the CT scans to obtain clear images with little metal artifact, we could easily detect lesions and joint space communication. This study demonstrated that plain radiographs underestimated osteolysis, and that lesions around posterior femoral condyles were the most difficult to identify on radiographs. Although most of the lesions were small and may be of little clinical importance, this study confirmed that MDCT can accurately detect osteolysis and measure lesion volumes in alumina-ceramic TKA.


C.C. Lee W.P. Lin L.C. Horng C.C. Jiang

We conducted a prospective, randomized study comparing the outcomes of total knee arthroplasty (TKA) respectively through a quadriceps-sparing (QS) approach and a MIS medial parapatellar (MP) approach at 2-year follow-up. Sixty patients (80 knees) with primary osteoarthritis were enrolled in this study. Patients were blinded to be treated with and randomized to be grouped by either MP group (40 knees) or QS group (40 knees). Thirty-seven MIS MP TKAs and thirty-eight QS TKAs completed the 2-year follow-up.

According to the isokinetic study, the recovery of muscle strength (peak muscle torque) and normalization of muscle balance (H/Q peak-torque ratio) were comparable in both groups at either 2-month or 2-year follow-up. Tourniquet and surgical time in the QS group was significantly longer (approximately 20 minutes) than that in the MP group. The hip-knee-ankle axis measured after surgery was significantly more varus in the QS group than that in the MP group. The axis in both groups did not significantly progress at 2-year follow-up. There were no infections and no revisions at 2-year follow-up in both groups. More outlier cases (4 knees) were noted in the QS group when compared with the MP group (no outlier).

However, no differences regarding the clinic outcomes (including VAS, HSS knee score, ROM and satisfaction) were observed between these two groups after either two months or two years upon operation. In both groups, there was a significant improvement of these parameters at 2-year follow-up in contrast with 2-month follow-up and pre-operative status.

In this study, we conclude that MIS medial parapatellar TKAs could achieve comparable recovery of muscle strength, normalization of hamstring-quadriceps muscle balance and clinical outcomes when compared with QS TKAs; moreover it provides more reliable alignment and fewer complications than quadriceps-sparing TKAs.


RC Wasielewski KC Sheridan RS Palutsis

Great disparity appears in the literature regarding the occurrence of minor and major complications after two-incision total hip arthroplasty (THA). Advocates of twoincision THA contend that this minimally invasive surgical (MIS) technique provides faster rehabilitation with fewer restrictions and financial advantages stemming from shorter hospital stays and quicker returns to work. These advantages, however, cannot be fully realized unless the procedure can be performed within acceptable risk levels.

The operative, perioperative, and postoperative complications of a consecutive series of 200 two-incision THAs from a single surgeon were analyzed. Of the 8 femur fractures which occurred in this series, four occurred intraoperatively. All four were nondisplaced and treated with a cerclage cable through the anterior incision. The prosthesis was retained in each case. Of the four postoperative fractures, two were nondisplaced, permitting retention of the prosthesis. These were treated with a trochanteric plate with wiring above and below the lesser trochanter. The other two postoperative fractures were displaced, necessitating revision to a longer, uncemented stem and cerclage wiring.

Other complications in this series included two nondisplaced greater trochanter fractures > 2cm, 14 asymptomatic greater trochanter fractures ≤2 cm, one malpositioned cup requiring revision, one loose stem, seven cases of heterotopic ossification ≥Grade 2, four dislocations, one superficial infection, 80 lateral femoral cutaneous nerve neuropraxias (78 of which resolved within six weeks), and four femoral nerve neuropraxias (three of which resolved in 6 to 12 weeks).

In this series, two-incision THA was performed with a low incidence of major complications but a high incidence of minor complications. Despite the minor complications, most patients experienced an accelerated recovery and rehabilitation owing to reduced tissue trauma.

To help surgeons avoid complications, we recommend periodic retraining sessions where concerns and pitfalls can be addressed and recent enhancements, taught.

Superficial nerve complications, such as those encountered in high numbers in this series, can be avoided by moving the anterior incision slightly lateral and splitting the fibers of the tensor fascia lata. The risk of minor trochanteric fractures can be reduced by first lateralizing broach-only stems with a long straight 9mm reamer and/ or by using direct visualization.


D. Janssen D. Waanders K.A. Mann N. Verdonschot

The stability of cemented hip implants relies on the fixation of the cement mantle within the bone cavity. This fixation has been investigated in experiments with cement-bone interface specimens, which have shown that the cement-bone interface is much more compliant than is commonly assumed. Other studies demonstrated that the mechanical response of the interface is dependent on penetration of the cement into the bone. It is, however, unclear how cement penetration exactly affects the stiffness and strength of the cement-bone interface. We therefore used finite element (FE) models of cement-bone specimens to study the effect of cement penetration depth on the micromechanical behavior of the interface.

The FE models were created based on micro computed tomography (micro CT) data of two small cement-bone interface specimens (8x8x4 mm). The specimens had distinct differences with respect to interface morphology. In these models we varied the penetration depth, with six different penetration levels for each model. We then incrementally deformed each model in tension and in shear, until failure of the models. Failure was simulated to occur in the bone and cement when the local ultimate tensile stress was exceeded, by locally reducing the material stiffness to near zero. From the resulting force-displacement curves we established the apparent tensile stiffness and strength for each of the models.

Our results indicated that the strength and stiffness of the cement-bone interface increased with increasing cement penetration depth, both in tension and in shear. However, after reaching a certain penetration depth, both strength and stiffness did not further increase. This depth was dependent on the specific interface morphology. We furthermore found that the strength of the models was higher in shear than in tension. After failure of the models, damage was mainly found in the cement, rather than in the bone.

The FE-based techniques developed for the current study are suitable for exploration of a variety of aspects that may affect the cement-bone interface micromechanics, such as biological changes to the bone and variations of cement material properties.


Qing Liu YiXin Zhou HaiJun Xu Jing Tang ShenJie Guo QiHeng Tang

Prosthetic reconstruction of high-riding hips is technically demanding. Insufficient bony coverage and osteopenic bone stock frequently necessitate transacetabular screw fixation to augment primary stability of the metal shell. We sought to determine the validity of the previously reported quadrant system, and if needed, to define a specialized safe zone for augmentation of screw fixation to avoid vascular injuries in acetabular cup reconstruction for high-riding hips.

Volumetric data from computed tomography enhancement scanning and CT angiography of eighteen hips (twelve patients) were obtained and input into a three-dimensional image-processing software. Bony and vascular structures were reconstructed three-dimensionally; we virtually reconstructed a cup in the original acetabulum and dynamically simulated transacetabular screw fixation. We mapped the hemispheric cup into several areas and, for each, measured the distance between the virtual screw and the blood vessel.

We found that the rotating centers of the cups shifted more anterior-inferiorly in high-riding hips than those in ordinary cases, and thus the safe zone shifted as well. Screw fixation guided by the quadrant system frequently injured the obturator blood vessels in high-riding hips. We then defined a specialized safe zone for transacetabular screw fixation for high-riding hips.

We conclude that the quadrant system can be misleading and of less value in guiding screw insertion to augment metal shells for high-riding hips. A new safe zone specific to high-riding hips should be used to guide transacetabular screw fixation in these cases.


V. Antoci M.J. Phillips V. Antoci K.A.

Background: In the present study, the characteristics and mid-term to long-term outcomes of total knee arthroplasty (TKA) associated infections treated with different types of approaches were evaluated.

Methods: A retrospective study of the results of 71 infected TKA treated between August 1993 and August 2005. The data included medical records, gender, periprosthetic infection (PPI) classification, patients’ comorbidities, PPI diagnostic criteria, microbiology and histopathology results, surgical and antimicrobial therapy, treatment modality, complications, follow up, and treatment results.

Results: Median age was 70 years (range 43–88). Median follow-up 5.8 years (range 2–12). Thirty-three patients had multiple risk-factors for PPI. The main pathogens isolated were Coagulase-negative staphylococci 26 (37%), Staphylococcus aureus 16 (22.4%).

The treatment methods of TKA infection was two-stage exchange in 59 (83%), debridement and retention −5 (7.2%), arthrodesis −5 (7.2%), excision arthroplasty 2 (2.8%). At final followup, 17 knees (24%) had required reoperation: 10 knees (14%) -component removal for reinfection. Two knees were reinfected 3 times, three knees – two times. The median time to first reoperation for reinfection was 1.2 years (range, 0.04–2.5 years). By Kaplan-Meier survival analysis the estimated survivals free of reoperation for infection were 90.5% (confidence intervals, 85.3–96.1%) at 5 years and 82% (confidence intervals, 70.3–94.5%) at 10 years. The Knee Society scores: Pain scores, Functional scores, ROM improved.

Conclusions: TKA infections treatment is a difficult task leading to a high rate of unsatisfactory mid-term and long-term results. About one forth of patient require reoperation, 14% become reinfected in first 2.5 years. Half of reinfected patients get reinfected repeatedly. In most cases patients are reinfected with the same micro-organism but more virulent. TKA infection treatment option should be chosen according to the type of infection (acute or chronic), the duration of infection, the stability of the implant, the type of microorganism causing infection, bone quality and integrity, and the quality of the soft-tissue.


H. Warashina M. Matsushita M Hiroishi R Yoneda J Otsuka S Koh T Aoki H Inoue E Horii Y Osawa

Acetabular component malposition during total hip Arthroplasty (THA) increases the risk of dislocation, reduces the range of motion, and can be the cause of early wear and loosening. Variability in implant alignment also affects the result of THA. The purpose of this study was to compare acetabular cup positioning of three different approaches in THA.

Three different approaches for cementless THA were studied in 108 operations.

The direct anterior approach was used in 56, the anterolateral approach in 32 and the posterolateral approach in 50. The same cementless cup was used in all cases. The same surgeon performed all procedures with mini-incision surgery, using different approaches. To determine the accuracy of the cups, the inclination and anteversion angles were measured with a CT-investigation of the pelvis.

There were no statistical differences between the three groups regarding means of the inclination and anteversion angles. But a significant range of variance, the lowest variations being in the group of the direct anterior approach, the highest in the group of the anterolateral approach.


H. Ozturk A.M.H. Jones S.L. Evans P.B. Nair M. Browne

Excessive implant migration and micromotion have been related to eventual implant loosening. The aim of this project is to develop a computational tool that will be able to predict the mechanical performance of a cementless implant in the presence of uncertainty, for example through variations in implant alignment or bone quality. To achieve this aim, a computational model has to be developed and implemented. However, to gain confidence in the model, it should be verified experimentally. To this end, the present work investigated the behavior of a cementless implant experimentally, and compared the results with a computational model of the same test setup.

A synthetic bone (item 3406, Sawbones Europe AB, Sweden) was surgically implanted with a Furlong cementless stem (JRI, Sheffield, UK) in a neutral position and subjected to a compression fatigue test of −200 N to −1.6 kN at a frequency of 0.5 Hz for 50000 cycles. Measurements of the micromotion and migration were carried out using two linear variable differential transducers and the strain on the cortex of the femur was measured by a digital image correlation system (Limess Messtechnik & Software Gmbh).

A three-dimensional model was generated from computed tomography scans of the implanted Sawbone and converted to a finite element (FE) model using Simple-ware software (Simpleware Ltd, Exeter, UK). Face-to-face elements were used to generate a contact pair between the Sawbone and the implant. A contact stiffness of 6000 N/m and a friction coefficient of 0.3 were assigned. The analysis simulated a load of −1.6 kN applied to the head of the implant shortly post implantation. The motions and strains recorded in the experiment were compared with the predictions from the computational model. The micromotion (the vertical movement of the implant during a single load cycle), was measured at the proximal shoulder, at the distal tip of the implant and at the bone-implant interface. The maximum value calculated proximally using FE was 61.3 μm compared to the experimental value of 59.6 μm. At the distal end, the maximum micromotion from FE was 168.9 μm compared to 170 μm experimentally. As a point of reference, some authors have suggested that in vivo, fibrous tissue formation may take place at the bone-implant interface when the micromotion is above 150 μm. The maximum micromotion found computationally at this interface was 99 μm which is below the threshold value defined. The longitudinal strain over the surface of the bone was variable and reached values of up to 0.15% computationally and 0.4% experimentally; this may be related to the coordinate systems used. However, it was noted that digital image correlation identified qualitatively similar strain patterns, and has great potential for measuring low level surface strains on bone.

In conclusion, the good correlation between the computational modelling and experimental tests provides confidence in the model for further investigations using probabilistic analyses where more complex configurations (for example change in implant alignment) can be analyzed.


Raman Thakur

Failure of internal fixation of intertrochanteric fractures is associated with delayed union or malunion resulting in persistent pain and diminished function. We evaluated 15 elderly patients treated with a tapered, fluted, modular, distally fixing cementless stem.

At an average follow up of 2.86 years, mean Harris hip score improved from 35.90 preoperatively to 83.01 (P < 0.01). Fourteen stems had stable bony ingrowth and one stem was loose. Distal fixation with a tapered fluted modular cementless stem allows stable fixation with good functional outcome in a reproducible fashion in this challenging cohort of patients.


W.Y. Shon S. Biswal N.B. Giripunje

Transtrochanteric rotational osteotomy (TRO) is a controversial procedure with reported inconsistent results. We reviewed 50 patients (60 hips) who underwent this procedure for extensive osteonecrosis of the femoral head, focusing on varization to determine its effectiveness as a head-preserving procedure in young adults. The mean age of the patients was 28 years (range, 18–46 years). Using the Ficat-Arlet classification, 40 hips had Stage II and 20 hips had Stage III involvement. According to the classification system of Shimizu et al., the extent of the lesions were Grade C in 54 hips and Grade B in six hips; the location of the lesions were Grade c in 56 hips and Grade b in four hips. Minimum follow-up was 18 months (mean, 84 months; range, 18–156 months). The mean preoperative Harris hip score was 44.7 points (range, 32–62 points) which improved to an average postoperative score of 80.1 points (range, 44–100 points) at the latest follow-up. Forty-four hips showed no radiographic evidence of progression of collapse. Ten hips showed progressive collapse, seven hips showed progressive varus deformity, three hips had stress fractures of the femoral neck, and one hip had infection. We believe TRO with varization is worth attempting for extensive osteonecrosis of the femoral head in young adults, although failures and complications are not uncommon.


R. Valentini B Martinelli

We refer about our experience in treating of 30 Pts with periprosthetic fractures (15 involved the hip prosthesis and 15 involved knee prosthesis) from jan 2002 to june 2008 with three different kinds of locked plates. The first system used has been the L.I.S.S. based on titanium plates and screws with the screws inserted in the plate by thread holes, the second was the so-called O’Nil system with the steel plates and the titanium screws screwed in a titanium conical insert, the third hardware system was represented by steel screws and plates with the screws screwed on the thread plate hole.

The results have been good and excellent in the most part of the patients, with only one complication regarding a non-union and plate mobilisation settle using a bicortical screws series.

Moreover we present our biomechanical study based on the collaboration with the Mechanical Engineering Department of our University regarding the relationship “screw-plate” using the Finite Elements Method (FEM), outlining the specific features of the three individual system of locked plates.


K. I. Eleftheriou N. Ali R. Thakrar H. V. Parmar

A significant number of patients are affected by localised articular damage that is neither appropriate for traditional arthroplasty, nor for biological repair. A focal resurfacing system utilizing a matched contoured articular prosthetic (HemiCAP®) has been introduced for the treatment of such cases. Independent results on these implants are limited.

We retrospectively evaluated the use of this resurfacing system in 14 patients (13 male, one female), mean age 40.3 years (range 28–49) with focal femoral condyle defects. All procedures were performed by the same consultant orthopaedic surgeon. Clinical evaluation consisted of the Knee injury and Osteoarthritis Outcome Score (KOOS) assessment. Radiographic evaluation was conducted independently to look for signs of any migration of the prosthesis or any radiolucency around it.

10 patients were treated on the medial femoral condyle, two on the lateral, and two received bicondylar implants. Average follow-up was 20 months (range 6–42). All but two patients (no improvement) described a good to excellent response of their symptoms. The KOOS score at follow-up was 79.6, compared to 61.2 prior to treatment (p=0.03). No signs of device migration or radiolucency around the device were observed. None of the patients required re-operation, and there were no cases of superficial/deep infection, thromboembolic events or other significant complication.

Our short-term results demonstrate that the use of the joint preserving HemiCAP® system provides good pain relief and functional improvement in such patients.


P.K. Puthumanapully M. Browne A. New

Uncemented porous-coated total hip prostheses rely on osseointegration or bone ingrowth into the pores for a stable interface and long term fixation. One of the criteria for achieving this is good initial stability, with failure often being associated with migration and excessive micromotion. This has particularly been noted for long stem prostheses. To minimize micromotion and increase primary stability, a short stemmed implant ‘PROXIMA’(DePuy; Leeds, UK) with a prominent lateral flare was developed with the aim of providing a closer anatomical fit, more physiological loading and limiting bone resorption due to stress shielding. This study aims to simulate bone ingrowth and tissue differentiation around a well fixed porouscoated short stemmed implant using a mechanoregulatory algorithm and finite element analysis (FEA). Specific emphasis is made on the design of the implant and its effect on osseointegration.

An FE model of the proximal femur was generated using computer tomography (CT) scans. The PROXIMA was then implanted into the bone maintaining a high neck cut and adequate cancellous bone on the lateral side to accommodate the lateral flare and for osseointegration. A granulation tissue layer of 0.75mm was created around the implant corresponding to the thickness of the porous coating used. The mechanoregulatory hypothesis of Carter et al (J. Orthop, 1988) originally developed to explain fracture healing was used with selected modifications, most notably the addition of a quantitative module to the otherwise qualitative algorithm. The tendency of ossification in the original hypothesis was modified to simulate tissue differentiation to bone, cartilage or fibrous tissue. Normal walking and stair climbing loads were used for a specified number of cycles reflecting typical patient activity post surgery.

The majority of the tissue type predicted to be formed, simulating a month in vivo, is fibrous and indicates a weak interface proximally after this period. The stronger tissues, bone and cartilage occupy the mid-lower regions, indicating a strong interface distally. This can be explained by the unique lateral flare that provides extra stability to the distal regions of the implant, especially on the lateral side. The percentage of bone ingrown around the implant at different stages is also important and there was a significant rise from 15% after 10 cycles to about 30% after 30 cycles, simulating a month in vivo. It was also noted that initial bone formation was very high, even after a few cycles, which leads to a stronger interface early on. Fibrous tissue occupied around 45% at almost all stages and did not vary considerably.

Cartilage however, was replaced by bone as tissue differentiation occurred, reducing from about 30% after 10 cycles to 20% after 30 cycles. This further indicates the trend of tissue ossification through the regions of stronger tissues, gradually proceeding in the direction of the weaker tissues.

The unique lateral flare design and the seating of the implant entirely in the cancellous bed without any diaphyseal fixation provides contrasting results in terms of bone ingrowth around the implant. The lateral flare minimises micromotion and provides better stress distribution at the interface under the region. This accounts for a large percentage of the mid to distal regions under the flare being covered with either bone or cartilage. From the predictions of the algorithm, the significant lateral flare of the PROXIMA helps in stabilizing the implant and provides better osseointegration in the distal regions around the implant.


R.C. Takemoto S. Arno N. Kinariwala K. Chan D. Hennessy N.Q. Nguyen P.S. Walker J. Fetto

Over the last two decades, design modifications in cementless total hip arthoplasty have led to longer lasting implants and an increased success rate. However, there remains limitations to the cementless femoral stem implant. Traditional cementless femoral components require large amounts of bone to be broached prior to stem insertion (1). This leads to a decrease in host bone stock, which can become problematic in a young patient who may eventually require a revision operation during his or her lifetime. Osteopenia, only second to distal stress shielding can lead to aseptic loosening of the implant and stem subsidence, which also accelerates the need for a revision operation (24). Recent literature suggests that thigh pain due to distal canal fixation, micro-motion, uneven stress patterns or cortex impingement by the femoral stem is directly correlated to increased stem sizes and often very disabling to a patient (58). In this study, we sought to determine whether reducing stem length in the femoral implant would produce more physiologic loading characteristics in the proximal femur and thus eliminate any remaining stress shielding that is present in the current design. We analyzed the surface strains in 13 femurs implanted with

no implants,

stemless,

ultra short and

short stem proximal fill implants in a test rig designed to assimilate muscle forces across the hip joints, including the ilio-tibial band and the hip abductors.

Analysis of the resulting surface strains was performed using the photoelastic method. For each femur, intact and with the different stem length components in place, the fringe patterns were compared at the same applied loads. The highest fringe orders observed for all tests were located on the lateral proximal femur and medial proximal femur. The fringes decreased as they approached the neutral axis of bending (posterior and anterior). Distal fringe patterns were more prominent as the stem length increased. The results demonstrate that the stemless design most closely replicated normal strain patterns seen in a native femur during simulated gait. The presence of a stemless, ultra short and short stem reduced proximal strain and increased distal strain linearly, thereby increasing the potential for stress shielding. The stemless design most closely replicated normal strain patterns observed in a native femur and for this reason has the potential to address the shortcomings of the traditional cementless femoral implant.


R.H Hallock B.M. Fell

Long term clinical data and patient satisfaction is reported on 152 patients implanted with the UniSpacer interpositional spacer during the first four years of clinical use with a minimum 5-year, maximum 9-year follow-up. 156 UniSpacer™ Knee System implants were implanted in 152 patients (4 bilateral), for treatment of isolated medial compartment osteoarthritis over a 4-year period. The minimum follow-up for this group of patients is 5 years with a range of 60 to 108 months. Revisions to a TKR within one year of the implantation date during the first and second year of UniSpacer implantations were 6% and 5% respectively. By years three and four, the TKR revision rate within the first year had dropped to 0% (zero). The data reflects the improvement in surgical technique and the development of proper patient selection criteria. The long term data provides validation that the UniSpacerÔ can provide a successful, long term, bone preserving, treatment alternative to the current HTO, UKR or TKR procedures.


T M Coon M D Driscoll S Horowitz M A Conditt

Successful clinical outcomes following unicompartmental knee arthroplasty (UKA) depend on accurate component alignment, which can be difficult to achieve using manual instrumentation. A new technology has been developed using haptic robotics that replaces traditional UKA instrumentation. This study compares the accuracy of UKA component placement with traditional jig-based instrumentation versus robotic guidance.

85 UKAs performed using standard manual instrumentation were compared to 67 performed with a robotically guided implantation system without instrumentation. Each was performed using a minimally invasive surgical approach. The two groups were identical in terms of age, gender and BMI. The coronal and sagittal alignment of the tibial components were measured on pre-and post-operative AP and lateral radiographs. Postoperative tibial component alignment was compared to the pre-operative plan.

The RMS error of the tibial slope was 3.7° manually compared to 1.2° robotically. In addition, the variance using manual instruments was 9.8 times greater than the robotically guided implantations (p< 0.0001). In the coronal plane, the average error was 3.0 ± 2.2° more varus using manual instruments compared to 0.3 ± 1.9° when implanted robotically (p< 0.0001), while the varus/valgus RMS error was 3.7° manually compared to 1.8° robotically. The average depth of medial tibial plateau resection was significantly less with inlay tibial components (3.9 ± 0.9mm) relative to onlay tibial components (6.8 ± 0.9mm, p< 0.0001). In addition, a significantly higher percentage of robotic inlay patients went home the day of surgery (12% vs. 1%, p< 0.0001).

Tibial component alignment in UKA is significantly more accurate and less variable using robotic guidance compared to manual, jig-based instrumentation. By enhancing component alignment, this novel technique provides a potential method for improving outcomes in UKA patients.


K.F. Mohammad

The treatment of comminuted fractures of the radial remains controversial. When preservation of the radial head mechanics is required, the choice between open reduction and internal fixation and radial head replacement remains a difficult choice. Current literature does not provide guidelines but suggest that fracture complexity and technique are critical for success. We compared the outcomes of 30 patients who were treated with either open reduction and internal fixation or radial head replacements between 2005 and 2008.

Twenty six Mason type III and 4 Mason type IV fractures of the radial head were enrolled in the study. Twenty underwent open reduction and internal fixation (group I) and 10 underwent radial head replacements (group II). The mean age at operation was 37 and 49 years respectively and the duration of follow up 32 and 31 weeks respectively.

The indications for radial head replacement were severe comminution, primary fracture dislocations and fracture dislocations with radial head excised. All patients were evaluated for pain, motion, strength, stability and function using the Broberg and Morley functional rating index.

Elbow range of motion averaged 9 degrees (extension loss) to 97 degrees (flexion in group I and 10 to 98 degrees in group II. Average pronation and supination were 71.5 and 72 (group I) and 69 and 74.5 (group II). The loss in strength in flexion, supination and pronation between the groups were not comparable (P> 0.05). The Broberg and Morley functional rating score average was 81.9 (group I) and 82.2 (group II).

These results show that patients who were treated with open reduction and internal fixation did not have a significant advantage over patients who received radial head replacements in terms of range of motion, loss in strength and their functional rating score.


M. Takagi S. Kobayashi K. Sasaki Y. Takakubo H. Kawaji Y. Tamaki Masaji Ishii

Aim: To ameliorate surgical strategy of disabled rheumatoid hip joints, perioperative status and clinical features of the patients undergoing total hip arthroplasty (THA) were retrospectively evaluated.

Materials and Methods: 150 joints of 106 patients were studied (male/female rate; 1:6, mean age; 60 years and duration of the disease; 15 years). All patients received cemented THA (mean follow-up period; 8 years). Mode of bone defect with acetabular reconstruction type, femoral bone quality, survivorship, steroid use and complications were surveyed.

Results: In preoperative status, proturusio acetabuli was found in 37% with type I; 54%, II; 34% and III; 12% by Sotelo-Garza classification. Superior bone defect was recognized in 56%, collapse and/or defect of femoral head in 19%, and geode formation in 0.2%. Femoral medullar canal was classified as type A; 1%, type B; 53% and type C; 46% by Dorr classification. The presence of fracture before surgery was 5%. Anatomical reconstruction was achieved in all cases including application of 42% bone grafting (autogenous alone; 51%, application of artificial substitute; 39% and of cross-plating system; 10%). Acetabular revision rate due to aseptic loosening (%/years) was improved by graft methods (whole series; 5/8, any grafting; 6/8, autogenous alone; 8/8, artificial substitute; 4/8 and cross-plate system; 0/4). Revision rate for any reasons was 9% (aseptic acetabulum 5%, aseptic femur 5%, dislocation 2% and infection 1%). Dislocation (11%), infection (3%) and severe thrombotic events (1%) were experienced. Steroid use was found in 73%, associated with increased risk of protrusio acetabuli, superior bone defect with protrusio acetabuli and fractures.

Discussion and Conclusion: The study indicated that steroidal medication significantly related to the perioperative status of bone defects and perioperative fractures of rheumatoid patients undergoing THA. Improved ace-tabular procedures could promise better survivorship of the implant.


N. Dunbar A.D. Pearle D. Kendoff M.A. Conditt S.A. Banks

Unicompartmental knee arthroplasty (UKA) is an increasingly attractive and clinically successful treatment for individuals with isolated medial compartment disease who demand high levels of function. A major challenge with UKA is to place the components accurately so they are mechanically harmonious with the retained joint surfaces, ligaments and capsule. Misalignment of UKA components compromises clinical outcomes and implant longevity. Cobb et al. (JBJS-Br 2006) showed that robot-assisted placement of UKA components was more accurate than traditional techniques, and subsequently that the clinical outcomes were improved. Cobb’s method, however, employed rigid intraoperative stabilization of the bones in a stereotactic frame, which is impractical for routine clinical use. Robotic systems have now advanced to include dynamic bone tracking technologies so that rigid fixation is no longer required. The question is -Do these robotic systems with dynamic bone tracking provide the same accuracy advantages demonstrated with robotic systems with rigidly fixed bones? We compared robot-assisted and traditionally instrumented UKA in six bilateral pairs of cadaver specimens. In all knees, a CT-based preoperative plan was performed to determine the ideal positions and orientations for the implant components. Traditional manual instruments were utilized with a tissue-sparing approach to implant one knee of each pair. A haptic robotic system acting as a virtual cutting guide was used to perform the robot-assisted UKA, again with a tissue-sparing approach. Postoperative CT scans were obtained from all knees, and the 3D placement errors were quantified using 3D-to-3D registration of implant and bone models to the reconstructed CT volumes.

The magnitudes of femoral implant orientation error were significantly smaller for the robot-assisted implants compared to traditionally implanted components (4° vs 11°, p< 0.001), but the magnitudes of femoral placement error did not reach significance (3mm vs. 5mm, p=0.056). The magnitudes of tibial implant placement error were not significantly different (4mm vs. 5mm and 7° vs. 7°, p> 0.05).

Well-placed UKA implants can provide durable and excellent functional results, which is an increasingly attractive option for young and active patients with severe compartmental osteoarthritis who wish not to have or to delay a total knee replacement.

Previous studies have demonstrated significant improvement in implant placement accuracy and clinical results with robot-assisted surgery using rigid bone fixation. This study demonstrates it is possible to achieve significant accuracy improvements with robot-assisted techniques allowing free bone movement. Additional larger trials will be required to determine if these differences are realized in clinical populations.


A.M. Omari A.J. Barnett B.J. Burston N. Atwal G. Gillespie B. Squires R. Ramakrishnan

The aim of this study was to investigate the use of large diameter head THR to treat fractured neck of femur, and to demonstrate if this conferred greater stability.

Forty-six (46) independent, mentally alert patients with displaced intracapsular fractures underwent THR. Mean age was 72.1 years. Outcome measures were dislocation, reoperation/ revision rate, Oxford hip score (OHS), Euroqol (EQ-5D) and residential status. Data was collected prospectively, with review being carried out at 3 months and 1 year.

At mean follow-up (12.5 months) there were no dislocations. Reoperation, revision and infection rate were all 0%. Two patients died (4.3%). Mean pre-injury and postoperative OHS were 12.1 and 17.9 respectively. Mean pre-injury and postoperative EQ-5D index scores were 0.97 and 0.83 respectively. Mean postoperative walking distance was 2.5 miles. There were no changes in residential status.

This is the first published series utilizing 36-mm diameter metal-on-metal THR for the treatment of fractured neck of femur. We have demonstrated that it affords patients excellent stability with no recorded dislocations.


M.J. Kuhn M.R. Mahfouz M.R. Anderle R.D. Komistek D.A. Dennis D. Nachtrab

Many nonoperative techniques exist to alleviate pain in unicompartmental osteoarthritic knees including physical therapy, heel wedges and off-loading knee braces [1]. Arthritic knee braces are particularly effective since they can be used on a regular basis at home, work, etc. Previous knee brace studies focused on their ability to stabilize anterior cruciate ligament (ACL) deficient knees. A standard technique for analyzing brace effectiveness is the use of an athrometer to look at the range-of-motion. Although this is helpful, it is more useful to use X-ray or fluoroscopy techniques to analyze the in vivo 3-D conditions of the femur and tibia. One method for doing this is Roentgen Steroephotogrammetric Analysis, which uses a calibration object and two static X-rays to perform 3-D registration of the femur and tibia. This technique is limited to static and typically non-weight bearing analysis.

We have analyzed five patients with moderate to severe osteoarthritis in both step up and step down activities with two different knee braces and also without a knee brace. Fluoroscopy of the five patients performing these activities was obtained as well as a CT scan of the knee joint for each patient. 3-D models of the femur and tibia were obtained from manual segmentation and overlaid to the fluoroscopy images using a novel 3-D to 2-D registration method [2]. This allowed analysis of 3-D in vivo weight bearing conditions. This work builds off of an analysis where 15 patients were analyzed in vivo during gait with and without knee braces [3].

All five patients experienced substantially less pain when performing the step up and step down activities with a knee brace versus without a knee brace. It should be noted that none of the five patients were obese, which can limit brace effectiveness. Preliminary results show that medial condyle separation was increased by 1.4–1.6 mm when using a knee brace versus not using a knee brace during the heel-strike and 33% phases of step up and step down activities. Also, the condylar separation angle was reduced by an average of 1.5–2.5°. Finally, consistently less condylar separation was seen during step down versus step up activities (0.5–1 mm), which can be attributed to a greater initial impact force on the knee joint during step down versus step up activities.


J Velyvis S Horowitz M A Conditt

Unicompartmental knee arthroplasty is realizing a resurgence due to factors such as improved alignment and sizing of components during surgery. This study compares the early results of two implantation techniques – robotic-assisted and standard manual alignment guides – to evaluate how a new technology developed to improve accuracy affects early patient outcomes.

For this study, we chose a prospective consecutive series of 20 patients in each group to receive a medial unicompartmental knee arthroplasty. The patients were evaluated clinically using standard outcomes measures (Knee Society, WOMAC and Oxford scores) as well as for modes of failure. Average follow-up for the manual onlay technique was 12 months and for the robotic-assisted inlay technique was and 10 months. Patients were not statistically different in terms of BMI, age, or diagnosis (p> 0.05).

Knee society score (p=0.65), total WOMAC score (p=0.75) and Oxford knee score (p=0.88) were not statistically different between the three groups. Five patients in the robotic-assisted inlay group complained of persistent tibial pain that resolved in four patients. There were no revisions for the manual onlay implant group and there was one revision for persistent tibial pain in the robotic-assisted inlay group, consisting of a conversion to a standard manual onlay UKA tibial component.

Patient outcomes were similar with inlay robotic-assisted unicompartmental knee arthroplasty compared with conventional manual onlay implant techniques. Roboticassisted inlay components resulted in slightly increased complaints of tibial pain and had one revision for tibial pain, however the revision was to a standard onlay UKA tibial component.


K. Knahr A. Pokorny A. Frank

Background: Recently, the new phenomenon of “squeaking” noises emitted from THAs with ceramic-onceramic bearings has spared international interest. It shows a frequency of 0,7–19,5% in literature, but infrequently requires revision surgery. However, an even higher incidence of various other noises from those THAs audible to the human ear have become popular in the process: this noise can resemble clicking, grinding or creaking and can be caused by distinct movements, during longer periods of walking, or can be constant with movement. The incidence of those noises can reach up to 30% of THAs. However, memory has faded that other bearings like metal-on-metal and PE/ceramic have been associated with noises in the past.

Therefore we aimed to investigate the occurence of acoustic emissions in patients, who had all received the same implant but with alternate bearings, to investigate the nature of noise, duration and clinical consequence for all 3 bearings (polyethylene/ceramic, metalon-metal, ceramic-on-ceramic).

Method: Between 1999–2001, 360 patients were matched in a prospective randomised trial. All of them received a cementless Zimmer© Alloclassic Variall™ implant at the Orthopaedic Hospital Vienna – Speising, Austria with either a ceramic-on-ceramic bearing, a metal-on-metal bearing or a polyethylene/ceramic bearing. A questionnaire was sent via mail, including questions on first occurence of hip noise, information on the kind and duration of the phenomenon and possible adverse evaluation on behalf of the patient. In case of a positive report, the patient was invited to a clinical examination and radiographic analysis. In addition, a specialised audiography was conducted in patients with audible sensations. Finally, the SF-36 and WOMAC were analysed. A number of patients received further examination with methods of gait analysis in order to detect the distinct point of occurence of the noise during the gait cycle.

Results: 33 patients reported an audible phenomenon from their THA, 14 received a ceramic-onceramic bearing (Cerasul), 13 a polyethylene/ceramic bearing (Durasul) and 6 a metal-onmetal bearing (Metasul). The most common noise was a distinct clicking, followed by a creaking noise. Only 1 patient reported a squeaking sensation, he received a polyethylene/ceramic bearing.

Conclusion: The emission of specific noises from THAs of all bearings has been well documented in recent trials and could be verified in this survey of cementless THAs. No trend towards an increased incidence of noise from THAs with ceramic-on-ceramic bearings could be detected. Interestingly, the single case of „squeaking” was reported from a patient with polyethylene/ceramic bearing. Microseparation and subluxation of the femoral head with resulting edge loading and formation of stripe wear has recently been suspected as the main cause for “noisy hips.” So far 2 ceramic-on-ceramic hips of this study group population have been revised. Both articulations showed areas of stripe wear due to subluxation of the joint.


S M. Zingde F. Leszko R D. Komistek J P. Garino W J. Hozack D A. Dennis M R. Mahfouz

Previous clinical studies have documented the incidence of squeaking in subjects having a ceramic-onceramic (COC) THA. An in vivo sound sensor was recently developed used to capture sound at the THA interface. In this first study, it was determined that subjects having all bearing surface types demonstrated variable sounds. Therefore, in this follow-up study, the overall objective was to simultaneously capture in vivo sound and motion of the femoral head within the acetabular cup during weight-bearing activities for subjects implanted with one of four different ceramic-on-ceramic (COC) THA.

Twenty subjects, each implanted with one of four types of Ceramic-on-Ceramic THA (9 Smith and Nephew, 8 Stryker, 2 Wright Medical Technologies and 1 Encore) were analyzed under in vivo, weightbearing conditions using video fluoroscopy and a sound sensor while performing gait on a treadmill. Patients were pre-screened and two groups were defined: a group diagnosed as audible squeakers (9 THAs) and a control group of THA patients not experiencing audible sounds (11 THAs). Two tri-axial piezoelectric accelerometers were attached to the pelvis and the femoral bone prominences respectively. The sensors detect frequencies propagating through the hip joint interaction. Also, 3D kinematics of the hip joint was determined, with the help of a previously published 2D-to-3D registration technique. In vivo sound was then correlated to 3D in vivo kinematics to determine if positioning of the femoral head within the acetabular cup is an influencing factor.

For the audible group, two had a Smith and Nephew (S& N) THA, six a Stryker THA and one a Wright Medical (WMT) THA. Both of the S& N subjects, 5/6 Stryker and the Wright Medical subjects experienced femoral head separation. The maximum separation for those subjects was 4.6, 5.0 and 2.1 mm for the S& N, Stryker and WMT subjects, respectively. The average separation was 4.3, 2.0 and 2.1 mm for the S& N, Stryker and WMT subjects, respectively. For the eleven subjects in the control group, seven subjects had a S& N THA, two a Stryker and one each having a WMT and Encore THA. All 11 of these subjects demonstrated hip separation with the maximum values being 3.8, 3.4, 1.9 and 2.4 mm for the S& N, Stryker, WMT and Encore THA, respectively. The average separation values were 1.8, 2.3, 1.9 and 2.4 mm for the S& N, Stryker, WMT and Encore THA subjects, respectively.

Four distinct sounds were produced by subjects in this study, which were squeaking, knocking, clicking and grating. Only 3/20 subjects produced a “squeaking” sound that was detected using our sound sensor. One of these subjects had a Stryker THA and two had a WMT THA. Further analysis of the nine subjects who were categorized as audible squeakers revealed that only 0/2, 1/6 and 1/1 subjects having a S& N, Stryker and WMT THA, respectively, demonstrated a squeaking sound that was detected using our sound sensor. Both (2/2) S& N subjects demonstrated a knocking and clicking sound, but neither produced a grating sound, while 5/6 Stryker subjects produced a knocking sound, but only 1/6 demonstrated a clicking or grating sound. Besides the squeaking sound, the only other sound produced by the WMT audible squeaker was a knocking sound. Only 1/11 control group subjects demonstrated a squeaking sound, which was a subject having a WMT THA. With respect to the control group subjects having a S& N THA, 5/7, 1/7 and 3/7 subjects produced a knocking, clicking or grating sound, respectively. Only 1/2 subjects having a Stryker THA produced a knocking or grating sound.

This is the first study to compare multiple COC THAs in analyzing correlation of femoral head separation (sliding) and sound. It was seen that all the THA groups had occurrences of separation and each case of separation correlated with the sound data. These results lead the authors to believe that the influence of squeaking is multi-factorial, and not necessarily attributed only to the bearing surface material.


C.S. Ranawat

The recent introduction of modern ceramic-on-ceramic total hip arthroplasties have demonstrated excellent clinical and radiographic results without catastrophic failure such as implant fracture associated with earlier designs. In laboratory wear testing, ceramicon-ceramic provides the least volumetric wear among all bearing surfaces. In recent years, with modern ceramic-on-ceramic bearing surfaces, clinical results with 5-to 7-year follow up have been good to excellent in 95–97% of cases. In spite of excellent results, certain limitations still exist including occasional fracture, stripe wear, squeaking, and neck-socket impingement producing metallic third body. Future improvement in ceramics (and other hard-bearing surfaces) and its coupling with other hard bearing surfaces appears to have significant advantages in reducing dislocation, impingement, stripe wear and squeaking.


Dan. J. Berry

Metal-on-metal bearings have become popular in the last ten years because of a low wear rate combined with the ability to use large head sizes for conventional total hip arthroplasty (THA) and to facilitate resurfacing hip arthroplasty. Further advantages of metal-metal bearings include the fact that they are not at risk for fracture, and they can be made as modular or non-modular acetabular implants.

It was recognized early that metal-on-metal implants had the potential to increase serum ion levels, and this was demonstrated in a number of studies. The significance of elevated ion levels, however, for most patients has been primarily a theoretical concern of toxicity, carcinogenesis or mutagenicity, and to date very few, if any, systemic problems related to systemic metal ions have been documented with certainty. Nevertheless, most surgeons have avoided use of the implants in patients who are likely to become pregnant, patients with renal disease, or patients with major systemic illnesses which have a high likelihood of leading to renal disease. Furthermore, most have avoided using them in patients with known dermal metal allergies, even though the connection between dermal metal allergies and metal bearings has not been established.

Unexpectedly, an extremely important concern has emerged with metal bearings: the finding of local inflammatory reactions related to metal bearings. These inflammatory reactions can take several forms including pain with a milky effusion, local tissue necrosis, or large fluid collections or pseudotumors. The histology of these different reactions appears to be predominantly lymphocytic in nature and a term for at least some of these reactions has been coined “AVALS”. Whether these local reactions are primarily immunologic in nature or primarily related to dose of local metal ions or debris remains uncertain. While there is much still to be learned, it appears that certain patient populations may be at increased risk for metal reactions, possibly related to implant size (women and smaller patients). It also seems verticallyoriented implants, which create edge loading, increase wear and increase risk of local metal reactions.

Perhaps the most important question is the incidence of local metal reactions, which remains to be defined. To date the problems in most series have been infrequent, less than 1 or 2 percent. However, in a few selected series the incidence has been higher, and when screening has been done for asymptomatic patients with fluid or masses around the joint, the rate has been higher in at least one reported series.

Surgeons may interpret the importance of local metal reactions differently, but certainly ultimately incidence of this problem will have a very major effect on the future of these bearings.


J.N. Argenson S. Parratte X. Flecher JM. Aubaniac

Unicompartmental knee arthroplasty (UKA) is a logic procedure when osteoarthritis or avascular necrosis is limitad to one femorotibial compartment. The indications for the procedure includes osteoarthrosis or osteonecrosis with full-thickness loss of articular cartilage limited to one of the tibiofemoral knee compartments. Physical examination should ensure full range of knee motion. Frontal and sagittal knee stability has to be tested. A particular attention should be given to the state of the anterior cruciate ligament. The status of the patellofemoral joint should be analysed by physical examination and patellofemoral view at 30, 60 and 90° of flexion. Preoperative anteroposterior varus and valgus stress radiographs should be done to confirm the complete loss of articular cartilage in the involved compartment, the full thickness cartilage in the opposite compartment and the possibility of full correction of the deformity to neutral.

The so-called minimally invasive surgery (MIS) procedure using a specific instrumentation is able to provide quicker recovery since the extensor mechanism disruption is eliminated. More importantly the radiological evaluation has shown that precise implantation of the components is possible with an MIS approach which is important for the long term results of the arthroplasty. The clinical results at ten years of follow-up of cemented metal-backed UKA performed through a conventional approach have shown results comparable to those obtained with total knee arthroplasty. The in vivo kinematic evaluation of patients implanted with UKA has shown that kinematics similar to the normal knee can be obtained, enhancing the importance of a functional anterior cruciate ligament.

Recent design improvements have increased the femorotibial area of contact to accommodate high flexion angles. Additionally our experience has demonstrated that modern UKA is a valid alternative for young and active patients with unicompartmental tibiofemoral noninflammatory disease, including both osteoarthritis and avascular necrosis. Compared to medial UKA lateral UKA represents in our experience only 5% of all UKA implantations.

However the long term results of lateral UKA compares at least equally with those reported for medial UKA.


M. Tada K. Inui H. Yoshida S. Takei S. Fukuoka Y. Matsui K. Yoshida

Good mid-term results of Oxford UKA (OxUNI) for anteromedial osteoarthritis (OA) were reported. The designers of prosthesis reported a 98% 10-year survival rate for a combined series of phase I and II, and these findings were supported by published results from other series, with 10-year survival ranging from 91% to 98%. In order to obtain good results, the designers of this prosthesis mentioned the importance of adhering to strict indication for OxUNI, especially only for OA cases with intact anterior cruciate ligament (ACL). OxUNI combined with ACL reconstruction (ACLR) is a viable treatment option for only young active patients, in whom the ACL has been primarily ruptured. On the other hand, it was not clear whether the result of OxUNI combined with ACLR for OA with secondary ruptured ACL was good. In this study we compare the short-term results of OxUNI combined with ACLR for OA with secondary ruptured ACL with that for usual OA with intact ACL.

382 OxUNI were performed at two hospitals by one surgeon between January 2002 and August 2005. Among those, 367 cases, followed over two years postoperatively (272 patients, women: 283, men: 84) were assessed. Follow up ratio was 96.1%. The mean patient age at the time of surgery was 72.0 (47~93) years. The mean follow-up period was 39.3 (24~67) months. Thirty three knees of OA were treated with OxUNI combined with ACLR, by using synthetic graft. Clinical results were assessed by the Oxford Knee Score (OKS) and active range of motion (ROM). Patients are asked a series of 12 questions, and their response scores range from 0 (worse) to 4 (best) for each, yielding an overall score range of 0–48. All living patients were contacted, and the status of the implant was established at the time of last follow from hospital records. We evaluate the survival rate for OxUNI with or without ACLR, using the endpoint of revision for any reason.

The pre-and postoperative clinical scores were compared using the paired Student’s t-test. Survivor-ship curves were constructed using the Kaplan-Meier method, and survivorship between groups was compared using logrank and Wilcoxon methods. All analyses were performed using 95% confidence intervals and a P value of < 0.05 was considered significant.

The mean OKS at final follow-up was 42.1 (preoperative; 21.7), and the mean active ROM was 125.2° (preoperative; 113.4°). OKS and active ROM were significantly improved. There were no significant differences in OKS and active ROM between OxUNI with ACLR and OxUNI with intact ACL. Fourteen knees among 367 knees were revised; nine for loosening of tibial component, four for dislocation of bearing and one for progression of lateral OA. Overall 5-year survival rate was 95.6%. When survival rate was assessed separately with or without ACLR, that of OxUNI with intact ACL was 96.7% and that of OxUNI with ACLR was 83.8%. There was significant worse survival rate between the two groups (P=0.0071).

The 5-year survival rate for OxUNI with intact ACL was 96.7%, which was equivalent to those of original series from Oxford. However, 5-year survival rate for Oxford UKA with ACLR was 83.8% in our series. Four knees in nine of loosening of tibial component were replaced by OxUNI combined with ACLR. Therefore, even if ACL was reconstructed, the results of OxUNI for OA with secondary ruptured ACL was proved to be pessimistic.

There was significantly worse survival rate for OxUNI with ACLR, compared with OxUNI with intact ACL. So we conclude that combined ACL reconstruction and OxUNI for anteromedial OA with secondary ruptured ACL is not recommended, which must be treated with TKA.


W. L. Walter

Ceramic on ceramic articulations had been used since 1970s but with high failure rate.

More recent third generation alumina ceramic had improved results due to better material properties to resist wear and fracture and better methods of fixation with metal back acetabular components. A new clinical problem of squeaking has emerged in the last decade and is now a relatively common occurrence in ceramic on ceramic total hip arthroplasty, with a reported incidence from less than 1% to 20% depending on the definition of the noise. We report experience with over 3000 ceramic-on-ceramic hips including the 10 year minimum follow-up of the first 301 cases.

Methods: Between June 1997 and Feb 1999, 301 consecutive primary cementless hip arthroplasties were performed on 283 patients under the care of the two senior authors. The mean age of the patients was 58.

All patients are asked on follow-up as part of a questionnaire: Has your hip ever made a squeaking noise? To date of the more than 3000 ceramic on ceramic hips that we follow, 74 hips (71 patients) responded yes to this question. Patient demographic and outcome data were analysed in all squeaking hips and compared with all primary ceramic on ceramic hips operated on at our unit.

Results: Of the first 301 cases there have been 9 revision surgeries in 8 hips as follows.

Two acetabular components revised for psoas tendonitis, one of these subsequently had both components revised for acetabular osteolysis with femoral revision to improve anteversion.

There were six other femoral component revisions: four for periprosthetic femoral fractures, one for aseptic loosening and one for transient sciatic nerve palsy. There has been one squeaking hip in this group not requiring revision due to the mild and intermittent nature of the noise. All complications occurred within the first 3 years, no further complication has arisen since.

When comparing the 74 squeaking hips to the entire cohort of primary hips we found that taller, heavier and younger patients are significantly more likely to have hips that squeak.

Squeaking hips have a significantly higher range of post-operative movement than silent hips.

Squeaking hips have a significantly higher Harris hip score. There was no difference in the satisfaction scores between squeaking and silent hips.

Conclusion: In summary, we have reported the large series of third generation alumina ceramic on ceramic articulation with 10 year results, and have demonstrated that it can produce excellent survivorship with good clinical and radiographic outcome. We believe that this result had provided very encouraging evidence to support the use of third generation ceramics as articulation for primary hip arthroplasty, especially in young and active patients.


K. Kobayashi M. Sakamoto Y. Tanabe T. Sato A. Ariumi G. Omori Y. Koga

Progression of osteoarthritis (OA) of the knee is related to alignment of the lower extremity. Postoperative lower extremity alignment is commonly regarded as an important factor in determining favourable kinematics to achieve success in total knee arthroplasty (TKA) and high tibial osteotomy (HTO). An automated image-matching technique is presented to assess three-dimensional (3D) alignment of the entire lower extremity for natural and implanted knees and the positioning of implants with respect to bone.

Sawbone femur and tibia and femoral and tibial components of a TKA system were used. Three spherical markers were attached to each sawbone and each component to define the local coordinate system. Outlines of the 3D bone models and the component computer-aided design models were projected onto extracted contours of the femur, tibia, and implants in frontal and oblique X-ray images. Threedimensional position of each model was recovered by minimizing the difference between the projected outline and the contour. The relative positions were recovered within −0.3 ± 0.5 mm and −0.5 ± 1.1° for the femur with respect to the tibia, −0.9 ± 0.4 mm and 0.4 ± 0.4° for the femoral component with respect to the tibial component, −0.8 ± 0.2 mm and 0.8 ±0.3° for the femoral component with respect to the femur, and −0.3 ± 0.2 mm and −0.5 ± 0.4° for the tibial component with respect to the tibia.

Clinical applications were performed on 12 knees in 10 OA patients (mean age, 72.5 years; range, 62–87 years) to check change in the 3D mechanical axis alignment before and after TKA and to measure position of the implant with regard to bone. The femorotibial angle significantly decreased from 187.8° (SD 10.5) to 175.6° (SD 3.0) (p=0.01). The 3D weight-bearing axis was drawn from the centre of the femoral head to the centre of the ankle joint. It intersected significantly medial (p=0.01) and posterior (p=0.023) point at the proximal tibia before TKA. The femoral component rotation was 3.8° (SD 3.3) internally and the tibial component rotation was 14.1° (SD 9.9) internally. Compared with a CT-based navigation system using pre-and post-operative CT for planning and assessment, the benefit to patients of our method is that the post-operative CT scan can be eliminated.


Dr Bharat S. Mody

The performance of high flexion postures such as cross legged sitting, are not part of the assessment criteria to assess either function of a natural knee joint or after Total Knee Replacement (TKR) surgery, in assessment systems used by the orthopaedic fraternity today. This is probably because TKR was initially developed and widely employed in the western countries. However, increasing numbers of this surgery are being performed in the eastern parts of the world, comprising more than half of the global population, where postures such as cross legged sitting are a basic necessity of activities of daily living.

It has been a general perception that achieving flexion beyond 120 degrees after Total Knee Replacement surgery is not a routine result. The implant manufacturing industry has recognized this need and put implant designs on the market with accompanying literature which would suggest that the implant design itself contributes towards a higher range of movement post surgery.

We have performed a prospective study involving a hundred Total Knee Replacements using standard implants (PFC Sigma, Cruciate Sacrificing design, Depuy, J& J, NJ, USA). This implant is not supposed to be specifically designed to deliver a high range of flexion. We found that incorporating certain specific surgical steps as a standard part of the operative procedure delivers a high range of flexion greater than 135 degrees in seventy five percent of patients which allowed them to adopt the cross legged sitting posture after surgery.

This paper conveys the message that achieving a high range of flexion after surgery does not need any special implant design. It discusses the surgical steps which seem to contribute towards this result. The implications in terms of cost saving for health care system are immense.


T.R. Yoon K.S. Park K. Thevarajan Y.J. Cho H.K. Yang

We performed this study to evaluate the clinical and radiological results of metal on metal articulation change for the treatment of ceramic liner or head fractures in total hip arthroplasty (THA).

We retrospectively reviewed 8 patients with revision THA using liner cementation (metal on metal) due to ceramic fracture (liner fracture; 5 cases, head fracture; 3 cases).

They were followed up for an average of 30 months (range 12 to 68 months). At the surgery, we removed ceramic liner and head, the joint cavity was irrigated with saline to remove remnants of ceramic particles. After that, the inner surface of the metal shell was roughened with a high-speed diamond burr to improve the fixation strength of the liner.

Metal inlay polyethylene (Metasul®, Centerpulse Orthopedics, Austin, TX) liner was used and the back surface of the liner was routinely down sized and roughened like spider web with an electrical burr to ensure stable fixation with bone cement.

We evaluated clinical result using Harris Hip Score (HSS) and the Western Ontario and McMaster Universities Osteoarthritis index (WOMAC) score and radiological evaluation was done using the mothod of DeLee and Charnley for the acetabular osteolysis and method of Gruen et al. for the femoral osteolysis.

The mean Harris hip scores improved from 65.3 pre-operatively to 93.8 at the final follow-up. There were no changes in cup position, no progression of osteolytic lesion around the femoral and acetabular components and no measurable wear of metal on metal bearing articulation at the last follow-up radiographs. There was one case of recurrent dislocation after surgery and the patient treated with greater trochanter distal advancement.

This study showed that for the treatment of ceramic liner or head fractures, after thorough removal of ceramic particles, cementation into a metal shell and changing the articulation to metal-on-metal provided good clinical and radiological results.


R. Nizard A. Cogan D. Hannouche A. Raould L. Sedel

Hard-on-hard bearing surface have been accepted as a valuable alternative for young and active patients needing a hip replacement because these combinations are resistant to wear. Initial development of alumina-on-alumina bearings faced complications such as fractures, and socket loosening. But, with the increasing number of prostheses implanted, noise occurrence appeared as a new complication. The primary aim of the present survey was to quantify the prevalence of having noise in a population receiving alumina-on-alumina hip arthroplasty.

Two hundred and eighty-four ceramic-on-ceramic hips were performed in 238 patients (126 males and 112 females) from January 2003 to December 2004. The average age at the index operation was 52.4 ± 13.4 years (range, 13 to 74 years). We used the same type of prosthesis for all patients manufactured in all cases by Ceraver-Osteal®. Clearance between femoral and insert was between 20 and 50 microns in order to achieve minimal wear. The survey was conducted by an independent surgeon who did not participated in patients care during the last 6 months of 2007. He interviewed the patients by phone with a standardized questionnaire (appendix) that aimed to assess if noise was present and the characteristics of this noise if present. No suggestion was done on how they could describe the noise and they felt free to use the word that they considered to be the most adapted. Satisfaction was evaluated asking if the patient was very satisfied, satisfied or dissatisfied with its prosthesis.

When the noise was present, the X-ray was independently evaluated to assess if sign of component fracture was present.

Four patients (six hips) died of unrelated cause during the follow-up. Three patients (three hips) lived outside France and could not be followed (1.3%). Nine patients (ten hips) could not be traced and are considered lost to follow-up (3.8%). Two hundred and twenty-two patients with 265 hips were therefore surveyed. Among these 265 hips, 28 experienced noise generation (10.6%). It was defined as a snap for 6 patients, as a cracking sound by 6, as rustling by 6 patients, as a squeaking by 7 patients (2.6%), a tinkling by 2 patients, one patient was unable to define the sound she felt. No factor related to the patient influenced the occurrence of noise. Twelve patients were dissatisfied with the result of the hip prosthesis, 5 of them experienced noise (41.7%); 210 were satisfied or very satisfied 23 of them experienced noise (11%); this difference was significant (p=0.002). No patients required revision for noise.

The origins of noise occurrence are unknown but several hypotheses can be suggested.

Squeaking may be due to absence of sufficient lubrication. Other types of noise can be due to microseparation, occult dislocation, impingement between the femoral neck and the acetabular rim but demonstration remain an issue.


PJC Heesterbeek NLW Keijsers N Verdonschot AB Wymenga

Balancing the PCL in a PCL-retaining total knee replacement (TKR) is important, but sometimes difficult to execute in an optimal manner. Due to the orientation of the PCL it is conceivable that flexion gap distraction will lead to anterior movement of the tibia relative to the femur. This tibio-femoral repositioning influences the tibio-femoral contact point, which on its turn affects the kinematics of the TKR. So far, the amount of tibiofemoral repositioning during flexion gap distraction is unknown which leads to uncertain kinematic effects after surgery. The goal of this study was to quantitatively describe the parameters of the flexion gap (gap height, anterior tibial translation and femoral rotation) and their relationship while the knee is distracted during implantation of a PCL-retaining TKR with the use of computer navigation. Furthermore, the effect of PCL elevation angle on the flexion gap parameters was determined.

In 50 knees, during a ligament-guided TKR procedure, the flexion gap was distracted with a double-spring tensor with 100 and 200 N after the tibia had been cut. The flexion gap height, anterior tibial translation and femoral rotation were measured intra-operatively using a CT-free navigation system. PCL elevation was calculated based on the femoral and tibial insertion sites as indicated by the surgeon with the pointer of the navigation system.

To identify a relationship between flexion gap height increase and anterior tibial translation, the ratio between anterior translation and gap height increase was determined for each patient between 100 and 200 N.

The mean gap height increased 2.2 mm (SD 0.96) and mean increase in anterior tibial translation was 4.2 mm (SD 1.6). Hence, on average, for each mm increase in gap height, the tibia moved 1.9 mm (SD 0.96) in anterior direction. Knees with a steep PCL showed significantly more AP translation for each mm gap height increase (gap/AP-ratio was 1 : 2.31 (SD 0.63)) compared to knees with a flat PCL (gap/AP-ratio was 1 : 1.73 (SD 0.50)).

The increase in femur (exo)rotation was on average 0.60° (SD 1.4).

With a tensioned PCL the tibia will move anteriorly on average 1.9 mm for every extra mm that the flexion gap is increased. The flexion gap dynamics can be explained in part by the orientation of the PCL: the greater the elevation angle, the more anterior tibial displacement during distraction of the flexion gap. The surgeon must be aware that distraction of the flexion gap influences the tibiofemoral contact point. The tibio-femoral contact point will move posteriorly and stresses in the PCL will rise and produce limited flexion and pain. In case of a conforming insert AP-movement will be limited but high PE stresses may be introduced that can lead to wear. This information may be helpful in selecting the optimal soft tissue balancing procedure and the optimal PE insert thickness in PCL retaining TKR.


H. Enomoto T. Nakamura S. Yanagimoto H. Kaneko Y. Fujita A. Funayama Y. Suda Y. Toyama

In the light of the increasing popularity of femoral resurfacing implants, there has been growing concern regarding femoral neck fracture. This paper presents a detailed investigation of femoral neck anatomy, the knowledge of which is essential to optimise the surgical outcome of hip resurfacing as well as short hip stem implantation.

Three-dimensional lower limb models were reconstructed from the CT-scan data by using the Mimics (Materialise NV, Leuven, Belgium). We included the CT data for 22 females and nine males with average age of 60.7 years [standard deviation: 16.4]. A local coordinate system based on anatomical landmarks was defined and the measurements were made on the unaffected side of the models.

First, the centre of the femoral head was identified by fitting an optimal sphere to the femoral head surface. Then, two reference points, one each on the superior and the inferior surface of the base of femoral neck were marked to define the neck resection line, to which an initial temporary neck axis was set perpendicular. Cross-sectional contours of the cancellous/cortical border were defined along the initial neck axis. For each cross-sectional contour, a least-square fitted ellipse was determined. The line that connects the centre of the ellipse at the base of the femoral neck and the centre of the femoral head was defined as the new neck axis. The above process was repeated to reduce variances in the estimation of the initial neck axis. The neck isthmus was identified according to the axial distributions of the cross-sectional ellipse parameters.

The short axis of the ellipse decreased monotonically since it was calculated from the center of the femoral head to the neck resection level (base of neck), whereas the long axis changed with the local minima. The cross section at which the long axis of the fitted ellipse had the local minima was determined as the neck isthmus.

The following measurements were made on the proximal part of the femur. The neck axis length measured from the center of the femoral head to the lateral endosteal border of the proximal femur was 67.3 mm [6.4]. The length between the center of the femoral head and the neck isthmus was 22.5 mm [2.7]. The diameter of the ellipse long axis at the neck isthmus was 27.6 mm [3.5] and was 23.6 mm [3.3] for the short axis.

The center of the neck isthmus did not align with the neck axis. The deviation of the isthmus from the neck axis which we defined as the isthmus offset was 0.7 mm [0.4].

If an alternative neck axis was defined between the center of the femoral head and the center of the neck isthmus, there would be a certain degree of angular shift with respect to the original neck axis. An angular shift of 1.8 degrees between the two axes can be expected for a 0.7-mm isthmus offset. In the worst case, an angular shift of 4.59 degrees was estimated for a subject with the largest isthmus offset of 1.93 mm.

Further investigations would be necessary to determine the axis configuration that represents the clinically relevant centre of the femoral neck. In order to reduce the deviations in the three-dimensional determination of the femoral neck axis, the reference anatomical landmarks and methods of evaluation should be carefully selected.


Y. Takahashi G. Pezzotti A. Kakimoto J. Hashimoto N. Sugano

Multiaxial rotation of femoral component is generated in a wide range against UHMWPE tibial insert during ambulation or deep bending activities. Simultaneously, microscopic oscillation and twisting might accompany with such a wide-range motion.

Such a combined in-vivo kinetics is expected to bring more severe wear to the sliding surface of knee joint prostheses than that in a case of single macro-kinetics (i.e., that commonly reproduced by conventional wear simulators). In order to reproduce clinical surface degradation correctly and quantitatively in simulator tests, we have to consider microscopic motions at the joint bearing surfaces. The purpose of this study is to analyze the influence of the composite knee motion on wear using a non-destructive spectroscopic approach.

The crystalline phase in UHMWPE is pre-oriented in the tibial insert from the manufacturing process, but the orientation of crystalline lamellae is sensitive to mechanical loading. Therefore, the orientation of the crystalline lamellae on the surface of retrieved UHMWPE tibial inserts could reflect the local motions in vivo generated in the joint during ambulation. The visualization of (orthorhombic) crystalline lamellae might ultimately lead to the possibility of tracking back the wear history of the joint. In this study, polarized Raman spectroscopy was employed in order to non-destructively visualize the lamellar orientation in UHMWPE tibial inserts, which were retrieved after exposures in human body elapsing several years.

According to this Raman analysis and in comparison with an unused insert, the orientation of surface lamellae was found to have been clearly changed due to wear in accordance to the local motion of the femoral component. Additionally, we could obtain information about the origin of delamination from the in-depth profile for lamellae orientation angle. This study not only shows the possibility of optimizing the UHMWPE structure to minimize wear but also gives a hint for the development of knee simulators of the next generation.


J. Victor D. Van Doninck L. Labey

The understanding of rotational alignment of the distal femur is essential in total knee replacement to ensure that there is correct placement of the femoral component. Many reference axes have been described, but there is still disagreement about their value and mutual angular relationship. Our aim was to validate a geometrically-defined reference axis against which the surface-derived axes could be compared in the axial plane. A total of 12 cadaver specimens underwent CT after rigid fixation of optical tracking devices to the femur and the tibia. Three-dimensional reconstructions were made to determine the anatomical surface points and geometrical references. The spatial relationships between the femur and tibia in full extension and in 90° of flexion were examined by an optical infrared tracking system.

After co-ordinate transformation of the described anatomical points and geometrical references, the projection of the relevant axes in the axial plane of the femur were mathematically achieved. Inter-and intra-observer variability in the three-dimensional CT reconstructions revealed angular errors ranging from 0.16° to 1.15° for all axes except for the trochlear axis which had an interobserver error of 2°. With the knees in full extension, the femoral transverse axis, connecting the centres of the best matching spheres of the femoral condyles, almost coincided with the tibial transverse axis (mean difference −0.8°, SD 2.05). At 90° of flexion, this femoral transverse axis was orthogonal to the tibial mechanical axis (mean difference −0.77°, SD 4.08). Of all the surfacederived axes, the surgical transepicondylar axis had the closest relationship to the femoral transverse axis after projection on to the axial plane of the femur (mean difference 0.21°, SD 1.77). The posterior condylar line was the most consistent axis (range −2.96° to − 0.28°, SD 0.77) and the trochlear anteroposterior axis the least consistent axis (range − 10.62° to +11.67°, SD 6.12). The orientation of both the posterior condylar line and the trochlear anteroposterior axis (p = 0.001) showed a trend towards internal rotation with valgus coronal alignment.


J.H. Currier D.W. Van Citters B.H. Currier A.S. Perry J.P. Collier

Squeaking of ceramic-on-ceramic (CoC) hips is a clinical phenomenon that is concerning with regard to the long term performance of these joint devices. Investigations into the cause of the squeaking have focused on patient factors and demographics, surgical placement, and other non-ceramic components in the devices. The current study tests latest-generation CoC devices to measure the vibration modes and frequencies of the components individually as well as assembled in the complete surgical construct.

Audio data from clinical cases of squeaking hips were analysed to determine the frequencies present. Retrieved CoC hips (n = 7) and never-implanted CoC bearing couples (n = 3) were tested in the laboratory for squeaking under loaded articulation.

Bovine serum was introduced into the CoC articulation and dried to promote stick-slip motion at the articulation. Squeaking sounds from the in vitro tests were recorded for audio analysis. Low mass, high frequency-response ceramic shear piezoelectric accelerometers (PCB Piezotronics) were adhered to the hip components along multiple axes to measure vibrations during testing.

Clinical audio shows that squeaking occurs at fundamental frequencies in the range of 1 to 3 kHz, with harmonics above the fundamental frequency. Retrieved CoC bearing couples squeaked at fundamental frequencies from 1.5 kHz to 3.8 kHz. Fourier Transform analysis of the audio closely matched the concurrent output from the accelerometers mounted directly on the ceramic components. This held true even in the absence of metal components in the system. With metal components included in the test construct (acetabular shell, acetabular cup, femoral stem), those components also vibrated at the same frequencies as the ceramic bearing couples, indicating that the CoC articulation is the source of the vibrations, with metal components conducting and emanating the sound.

The never-implanted bearing couples were made to squeak and vibrated at fundamental frequencies ranging from 1 kHz to 8 kHz.

Squeaking from CoC hips can be reproduced in the lab using components from clinical retrievals. Instrumentation of the explanted hips confirms that the vibration frequencies of the ceramic components themselves match the audible squeaking. The squeaking of ceramic components mounted with soft polymers and with no metal contact at any point indicates that the ceramic components themselves are the source of the clinical squeaking. The measured vibration of ceramic components in the audible range is an observation not predicted by modeling studies reported in the literature to date.


R. Strachan F. Iranpour P. Konala B. Devadesan S. Chia A. Merican A. Amis

Controversy still exists in the literature regarding efficacy and usefulness of CASN in knee arthroplasty. However, obsession with basic alignments and proper correction of mechanical axes fails to recognise the full future potential of CASN which seems to lie in enhanced dynamic assessment. Basic dynamics usually at least includes intraoperative assessment of limb alignments, flexion-extension gap balancing and simple testing through ranges of motion. However our upgraded CASN system (Brainlab) is also capable of enhanced assessment not only including the provision of data on initial to final alignments but also contact point observations. The system can also perform an enhanced ‘Range Of Motion’ (ROM) analysis including observation of epicondylar axis motion, valgus and varus, antero-posterior shifts as well as flexion and extension gaps. Tracking values for both tibiofemoral and patellofemoral motion have also been obtained after performing registration of the prosthetic trochlea.

Observations were then made using a set of standardised dynamic tests. Firstly, the lower leg was placed in neutral alignment and the knee put through a flexionextension cycle. Secondly the test was repeated but with the lower leg being placed into varus and internal rotation. The third test was performed with the lower leg in valgus and external rotation.

We have been able to carry out these observations in a limited case series of 15 total knee arthroplasties and have found it possible to observe and quantify marked intra-operative variation in the stability characteristics of the implanted joints before corrections have been made and final assessments performed. Indeed contact point observation has found several cases of edge loading before corrections have been made. Also ROM analysis has demonstrated the ability of the system in other cases to observe and then make necessary adjustments of implant positions and ligament balance which alter the amounts of antero-posterior and lateral translations. In this way paradoxical antero-posterior and larger rotational movements have been minimised. Cases where conversion to posterior stabilisation has been necessary have been encountered. Also patellar tracking has been observed during such dynamic tests and appropriate adjustments made to components and soft tissue balancing.

Although numbers in this case series are small, it has been possible to begin to observe, classify and quantify patterns of instability intra-operatively using simple stress tests. Such enhanced intra-operative information may in future make it possible to create algorithms for logical adjustments to ligament balance, component sizes, types and positions. In this way CASN becomes a more useful tool.


A. Borgwardt S. Ribel-Madsen L. Borgwardt B. Zerahn L. Borgwardt

A major concern in metal on metal bearings has been the elevated serum concentrations of cobalt and chromium. Recent papers have suggested that metal hypersensivity in a few cases could cause periprostetic lymphocyte accumulation leading prosthetic loosening.

To measure the lymphocyte activation and proliferation in vitro by re-exposure of the cells to cobalt, chromium, nickel and titanium. To correlate the lymphocyte assay data to the serum concentration of metals and plasma cytokines.

A prospective clinical study with the ASR (DePuy) and ReCap (Biomet) resurfacing hip implants. Blood samples were collected one and two years postoperatively, lymphocytes were isolated by density gradient centrifugation, cultured in a medium containing the patient’s serum and exposed to metal salts.

Cells were analyzed by flow cytometry, evaluating number, viability, size and CD69 activation.

A negative control and a positive control (phytohaemagglutinine) were included in the assay, and the responses to the metals were calculated in proportion to controls. 11 patients were assessed at one and two years follow up, 16 patients were assessed only at two years.

Serum chromium and cobalt were measured preoperatively, six months, one year and two years postoperatively by graphite furnace absorptiometry. Plasma cytokines were measured by multiplexed immunoassay.

In the assay the negative and positive controls gave the expected responses.

When exposed to metals no response was found in the lymphocytes in any patients.

There were no difference in response between one and two years.

The results seems to indicate that the metal hypersensitivity is a rare condition in metal on metal arthroplasty. The results indicate that the method can be used to monitor hypersensitivity to implant metals.


J.H. Currier I.M. Tomek B.H. Currier J.C. Huot M.B. Mayor D.W. Van Citters

A common feature of retrieved ceramic-on-ceramic (CoC) hips is the presence of metal transfer on the femoral head. This metal transfer represents an important change in the articulating surface and can have consequences in terms of lubrication, friction, wear, and squeaking. Given the potential impact of metal transfer on the performance of CoC bearing couples, a good understanding of the factors surrounding its occurrence is warranted. This study documents the metal transfer onto a ceramic femoral head with two subluxations onto the rim of the cup which occurred during surgery. This metal transfer is compared to that on other ceramic heads retrieved for various reported reasons, including squeaking, pain and loosening.

The first ten retrieved alumina heads of current ceramic technology (Ceramtec, Plochingen, Germany) submitted to our retrieval laboratory were assessed to document the phenomenon of metal transfer. Nine devices underwent in vivo service (mean duration 32 mo., range 13 to 84) and the tenth device was removed intra-operatively and serves as an instructive control case. It was impacted onto a trunnion and during final testing for stability subluxed anteriorly over the titanium lip of the cup. The metal transfer was immediately noted by the surgeon and the head was removed.

All ceramic heads were examined under light microscopy (Nikon Dissecting Microscope, Tokyo, Japan) and white light optical profilometry (NewView 7300, Zygo, Middlefield, CT).

The control ceramic head showed two distinct metal transfer streaks from two discrete subluxation events that were documented by the surgeon (IMT). Those streaks are aligned in a direction approximately 24o to the right (clockwise) of a line through the polar apex of the head and parallel to the axis of the femoral neck. Microscopy and profilometry indicate that they were laid down in a direction from equator-toward-pole.

Seven of the retrieved ceramic heads showed streaks of metal transfer that are very similar to those on the control ceramic head in terms of: alignment (equator-toward-pole, 20 to 45o off-axis) width (tapered point growing to approximately 1.0 to 1.5 mm), depth of metal deposition (0.25 to 0.40 μm), and depositional texture.

It is notable that the metal transfer streaks commonly observed on retrievals bear a close resemblance to that caused by a single intra-operative event wherein a hip abduction force pulled the head into contact with the titanium cup/liner rim. An important implication is that this demonstrates that metal transfer can occur with a single instance of rim contact, wherein the femoral head is forced against the metal cup rim. If metal transfer onto the head were to occur during final reduction of the hip, its presence may well be undetected and any deleterious in vivo impact of the metal transfer would be in effect from the day of surgery.


J.D. Johnston S.E. Kulshreshtha D.J. Hunter D.A. Wilson B.A. Masri

Objective: Unicompartmental knee arthropasty (UKA) has recently attracted increased popularity and usage, though issues exist regarding tibial component failure. UKA instability may be due to insufficient bony support at the proximal tibia. Pre-operative knowledge of ‘safe’ resurfacing depths offering subchondral bony support could help minimize UKA instability. We recently developed a novel CT imaging tool (CTTOMASD) which assesses subchondral bone mineral density (BMD) in relation to depth from the subchondral surface. The objective of this work was to determine the in-vivo precision of CT-TOMASD safe resurfacing depths in human tibial compartments.

Seven knees from seven donors (2M:5F; age:46+/−11) were scanned three times via QCT (GE Lightspeed; BMD Phantom; 0.625x0.625x0.625mm resolution). CTTOMASD regional analyses were performed for medial and lateral compartments; outputting density versus depth plots fit with polynomial regression equations. As density decreases with increased depth from the subchondral surface, a density threshold of 300mg/ cm3 was arbitrarily set to correspond with the safe resurfacing depth. The 300mg/cm3 density threshold corresponds to the average density of subchondral trabecular bone, and is ~2x the density of weak epiphyseal trabecular bone located beneath stiffer subchondral trabecular bone. Precision was defined using coefficients of variation (CV%).

In-vivo precision errors associated with CT-TOMASD safe resurfacing depths were less than 2.7%. CV% was 2.7% for the medial compartment depth and 2.6% for the lateral compartment depth.

CT-TOMASD demonstrates repeatable measures of safe resurfacing depths invivo.

Safe resurfacing depths are measured in relation to defined density thresholds which can be adjusted according to UKA design and patient specifics (e.g., size, sex). CT induces a low radiation dosage due to the low presence of radiosensitive tissues at the knee (~1/10th of a long-leg standing radiograph). CT-TOMASD has potential to be used as a pre-operative imaging technique for improved UKA stability and longevity.


S.D. Steppacher T.M. Ecker M. Tannast S.B. Murphy

Patients who are less than 50 years old at the time of total hip arthroplasty (THA) have been known to have higher failure rates than patients who are older. Wearinduced osteolysis and associated component loosening is the most common mode of failure reported. The current investigation prospectively assessed the survivorship and clinical results of alumina ceramic-ceramic THA in patients younger than 50 years.

238 consecutive hips in 201 patients treated by alumina ceramic-ceramic THA were studied. The mean age at operation was 41.4 ± 7.5 years (range, 18 – 50 years).

The preoperative Merle d’Aubigné score was 11.1 ± 1.6 (6 – 15). The preoperative diagnosis included primary osteoarthritis or impingement (105 hips, 44%), developmental dysplasia of the hip (90 hips, 38%), osteonecrosis of the femoral head (17 hips, 7%), post-traumatic osteoarthrosis (16 hips, 7%), and rheumatoid arthritis (6 hip, 3%). 144 hips (61%) were replaced with the use of surgical navigation for acetabular component positioning. The mean cup diameter was 51.8 ± 3.7 (range, 46 – 60 mm). 73 (31%) bearings were 28 mm and 165 (69%) bearings were 32 mm.

At mean follow-up of 5.6 ± 2.3 years (2 – 11 years), the mean Merle d’Aubigné score was 17.4 ± 0.9 (14 – 18). There were no radiographic signs of osteolysis. There were two revisions (0.8%): one for acute cup displacement and one for a ceramic liner fracture. In addition, one hip was treated by I& D for acute infection and another with I& D but without evidence of infection. Other complications included one greater trochanter fracture and one calcar fracture, both repaired at surgery, and one transient peroneal nerve palsy. The 10-year Kaplan Meier survivorship of the implants (revision of any component for any reason) was 98.7% (95% confidence interval 96.3–100%). There were no hip dislocations.

Results of THA in patients less than 50 years using alumina ceramic-ceramic bearings at two to eleven years follow-up are promising with no case of osteolysis or dislocation.


T. Fujii M. Kondo K. Tomari H. Kitagawa Y. Kadoya

Several anatomical landmarks are preferable in order to achieve the precise decision of femoral component rotation in order to achieve a satisfying result in total knee arthroplasty (TKA). The posterior condylar axis (PCA) is apparent and allows minimization of interobserver error compared with the transepicondylar axis or anterior-posterior axis. The rotation angle based on PCA observed during surgery differs from the angle measured on pre-and postoperative epicondylar view, because X-rays do not reflect the posterior condylar cartilage. We investigated the influence of the posterior condylar cartilage on setting the rotation angle of the femoral component in 184 knees in 112 patients with varus osteoarthritis undergoing TKA.

Medial and lateral thickness of the resected posterior femoral condyle was measured before and after removing the cartilage to determine its thickness. The amount of rotation angle influenced by the cartilage is expressed as an inverse trigonometric function (arctangent) of the distance between the posterior condylar surfaces and the difference in thickness between the medial and lateral cartilage.

Average thickness of the lateral and medial cartilage turned out to be 2.1±0.7mm and 0.7±0.7mm, respectively. The average rotation angle influenced by this difference was calculated to be 1.7±1.3°. These findings suggest that using PCA as a guide to determine the rotation angle of the femoral component results in approximately 1.5–2.0° of excess external rotation in varus osteoarthritis. Because of significant individual variability in condylar twist angle, formed by the intersection of the clinical epicondylar axis with the PCA, preoperative CT or epicondylar view is recommended in order to calculate this angle in each subject. Thickness of the posterior condylar cartilage should be taken into consideration when finalizing the rotation angle of the femoral component by PCA in addition to transepicondylar and anterior-posterior axis.


L.D. Angibaud B. Stulberg J. Mabrey D. Covall J. Steffens A. Hayes J Weisenburger H. Haider

A tibial insert with choices in posterior slope, size, and thickness is proposed to improve ligament balancing in total knee arthroplasty. However, increasing slope, or the angle between the distal and proximal insert surfaces, will redistribute ultra-high molecular weight poly-ethylene (UHMWPE) thickness in the sagittal plane, potentially affecting wear. This study used in-vitro testing to compare UHMWPE wear for a standard cruciate-retaining (CR) tibial insert (STD) and a corresponding 6° sloped insert (SLP). Our hypothe sis was that slope variation would have little effect on wear.

Two of each style inserts were tested on an Instron-Stanmore knee simulator with a force-control regime. The gait cycle and other settings followed ISO 14243-1 & 2, except for the reference position, which was posteriorly shifted 6 mm to simulate the worst-case scenario. The STD insert was tilted 6° more than the SLP to level the articular surfaces. Wear was gravimetrically measured at intervals according to strict protocol.

No statistical difference (p=0.36) was found between wear for the STD (9.5 ±1.8 mg/Mc) and SLP (11.4 ±0.5 mg/Mc) inserts.

The overall wear rate measured was higher than previously published rates using implants similar to the STD inserts. This may relate to the shift in the reference position and the 6° slope, leading to increased shear loads. This is the first time the effect of tibial insert slope on wear has been evaluated in-vitro. When limited to 6°, wear testing suggests that al tering the tibial insert slope will have a minor effect on UHMWPE wear.


Y. Kajino T. Kabata T. Maeda T. Murao H. Yoshida K. Tanaka K. Tomita

The position of the acetabular component affects the result of total hip arthroplasty(THA) in terms of postoperative dislocation, impingement, wear etc.

However, as it is much difficult to place the component in the appropriate position for the cases of severe acetabular deformity, we used a Computed tomography(CT)-based navigation for THA in such cases. Therefore, the purpose of this study was to estimate the accuracy of a CT-based navigation in terms of acetabular component positioning in THA for severe acetabular deformities.

13 patients (1 man, 12 women), 14 hips underwent THA using a posterolateral approach with a CT-based navigation. The diagnoses were severe developmental dysplasia (Crowe group III, IV) in 6, ankylosis in 3, destructive arthritis after infection in 2, Charcot joint, and arthrodesed hip. And, we evaluated the differences of component position from the center of the anterior pelvic plane(APP), anteversion angle, and inclination angle relative to APP between the intraoperative data from the navigation system and the data from postoperative CT. Considering the intra-observer error, the measurement was done three times respectively and the mean value was accepted. We also estimated the difference between the component size planned and that implanted.

The mean difference between intraoperative records and actual postoperative results of the component position shows 3.3 mm(range: 0–7.0, SD: 2.2) for the horizontal position, 3.2 mm(range: 0–9.7, SD: 4.5) for the vertical position, 4.4 mm(range: 2.0–7.7, SD: 1.6) for the antero-posterior position from the center of the APP, 1.3 degrees(range: 0–3.0, SD: 0.9) for the inclination and 2.9 degrees(range: 0.3–8.3, SD: 2.2) for the anteversion respectively. All components were placed in the safe zone by Lewinnek. The component size was predicted in 10/14(71.4%) hips. There were no complications related to the use of the navigation.

This study showed the accuracy of cup positioning using a CT-based navigation in THA for the cases of severe acetabular deformity. We concluded that this system was a useful tool for surgeon to identify orientation, implant acetabular component at the precise position and angle, and to reduce the incidence of some complications especially for patients with these severe acetabular deformities.


Robin Goytia Benjamin McArthur Philip Noble Sabir Ismaily David Irwin Molly Usrey Michael Conditt Kenneth Mathis

Several studies have suggested that, in TKR, gender specific-prostheses are needed to accommodate anatomic differences between males and females. This study was performed to examine whether gender is a factor contributing to the variability of the size, shape and orientation of the patellofemoral sulcus.

3D computer models of the femur were reconstructed from CT scans of 20 male and 20 female femora. The patellofemoral groove was quantified by measuring landmarks at 10 degree increments around the epicondylar axis. The orientation of the groove was defined by the tracking path generated by a sphere moving from the top of the groove to the intercondylar notch. To assess the influence of gender on the shape of the distal femur, all morphologic parameters were normalized for differences in bone size.

Overall, the distal femur was 15% larger in males compared to females. The male condyles were 4% wider than the female for constant AP depth (p=0.13). When normalized for bone size, there was no gender difference in most patello-femoral dimensions, including the length, width, angle or tilt of the sulcus. Female femora had a less prominent medial anterior ridge (p=0.07), and a larger normalized radius of curvature of the tracking path (p=0.03). In addition, the orientation of the sulcus differed by 1–2 degrees in both the coronal and axial planes. Overall, gender explained 4.7% of the anatomic variation of the parameters examined, varying from 0 to 15.9%.

The size, shape and orientation of the patello-femoral groove are highly variable.

While the patello-femoral morphology of male and female femora are very similar, some of the anatomic variability is related to gender, particularly the prominence of the medial ridge and the sulcus radius of curvature. The biomechanical and clinical significance of these differences after TKA have yet to be determined.


Sung-Do Cho Yoon-Seok Youm Chang-Yun Jung Ki-Bong Park

The purpose of this prospective study was to investigate the necessity of gender-specific design in total knee arthroplasty (TKA) for Korean women.

One hundred and seventeen women (151 knees) who underwent primary TKA by one surgeon with Nexgen® LPS (Zimmer, Warsaw, IN) were evaluated. The mean age was 70 (range 52–80) years. The size of the implant was determined by considering anteroposterior (AP) dimension and the amount of posterior condylar resection. Size C was used in 72 knees, size D in 57 and size E in 22. We measured the mediolateral (ML) widths of distal femur at four points (anterior, distal anterior, distal posterior, posterior) intraoperatively after bone cutting, and compared them with the ML widths of the corresponding femoral implants. The ML/AP ratio was calculated in each size group.

The mean ML widths of the distal femur checked at all four points were larger than those of the implants. The ML/AP ratio of the distal femur decreased as the size increased from C to E, especially that of the anterior point. Overhanging occurred in 7 cases (4.6%, size C -2 cases, size D -2 cases, E -3 cases) : Nexgen® LPS implant was used in 5 cases because there was only minimal antero-lateral overhanging, resulting in no postoperative problem such as pain or limited motion. Gender-specific design was used in only 2 cases (1.3%, size D -1 case, size E -1 case) with trochlear dysplasia due to general overhanging.

In conclusion, gender-specific design of Nexgen® TKA was rarely necessary in 117 Korean women(151 knees); overhanging occurred in 7 knees (6 women) and gender-specific design was used in only two knees (1.3%) with trochlear dysplasia. Further research is obviously mandatory to assess the necessity of gender-specific design.


Yves Catonné F Khiami H Sari Ali JY Lazennec

Introduction: In patients with gonarthrosis secondary to a femoral or a tibial mal union, the technical problems are different according to the localization and the importance of the deformity, the presence of boneless, the cutaneous and ligamenteous status and the degree of preoperative motion.

Material and Methods: Between 1995 and 2003, 34 TKR have been performed in patients with mal unions either post trauma (26 cases) either secondary to surgery (osteotomy with hypercorrection). There were 21 males and 13 females. The average age was 63 years (38 to 77) The mal union was localized to the femur (9 cases) or the tibia (23 cases) or to the both femur and tibia (2 cases). The deformity was variable : varus, valgus, flessum, recurvatum or rotationnal mal union. IKS scoring, HKA, MFA and MTA angles were evaluated pre and post operatively. 11 cases of intra articular mal unions, secondary to epiphyseal fractures were operated : a TKR posterostabilized (9 cases) or constrained (2 cases) was performed.

In the extra articular mal unions (23) the technique depended on the degre of intraosseous deformity : medial or lateral release or osteotomy performed when the intra osseous deformity was more than 10°. TKR was associated with an osteotomy in one time surgery in 5 femoral mal unions and 12 tibial deformities.

Results: The average follow up was 8 years (4 to 13 years). Complications consisted in 5 phlebitis, 2 superficial skin necrosis, 4 stiff knees (flexion less than 80°). There was no infection in this short serie. The average IKS score was 65 before and 163 after operation. The average flexion was 83° preoperatively and 98° after surgery. Average HKA angle was 167° pre and 182° post operatively in the varus deformities. In the valgus deformity it was 191° pre and 181° post surgery.

Discussion: Average IKS scoring is less good in post traumatic mal unions than in the habitual TKR specially because of the motion : the knee is often stiff preoperatively and remain often stiff postoperatively. A quadriceps release is sometimes indicated either during the TKR either in a second time. Constrained implants (constrained condylar knee or rotating hinge) are necessary in some cases of medial or lateral insuffisency of the collateral ligament.


J. B. Grimes

A higher than expected failure rate of the Zimmer Durom acetabular component has been reported. A study by Zimmer did not reveal a design defect. This study investigated impaction deformation of two cup designs.

Eleven Durom cups and modular heads (Zimmer, Warsaw, IN) were retrieved at an average of 13.9 months. The Birmingham Hip Resurfacing (Smith & Nephew, Memphis, TN) served as a control. Cups were impacted into a two-point acetabular loading model made of 30 grade urethane foam (Sawbones, Vashon, WA). A coordinate measuring machine with 2 micron (um) accuracy was used to map the inside diameters of the cups before, during and after impaction. Machinist’s dye was used to check head-cup contact.

The Durom porous coating was essentially devoid of tissue ingrowth. Two heads used with size 62/56 Duroms had equatorial wear stripes. The outside diameter of the Durom was 2.93±0.03mm larger than the nominal diameter. Dome wall thickness was 3.23±0.07mm for the Durom and 6.08±0.65mm for the BHR (n=11). Inside diameters of all cups had less than 10um deviation from roundness before impaction and after removal from the model. The mean diametral deformation of the Durom was 89.8±14.8um, significantly greater than the BHR, 57.2±25.0um (p< 0.002). Non-impacted cups exhibited polar contact—circular areas of dye at the dome with no contact near the rim. Duroms with greater deformation exhibited linear contact—a 2cm band of dye extending from rim to rim with no contact on either side of the band.

The Durom is a relatively thin-walled acetabular component with low clearance and an aggressive rim flare. Impaction of this cup into an acetabular model resulted in deformation which approached the diametral clearance. Maximal deformation with larger cups and warping of the articular surface correlated with observed wear stripes. The absence of residual cup deformation indicated deformation is a dynamic phenomenon which can be detected only under conditions simulating in vivo use. It is likely that impaction deformation, with consequent friction and wear, contributed to the early failure of the Durom acetabular component.


S. Matsuda H. Mizu-uchi H. Miura Y. Iwamoto

Total knee arthroplasty (TKA) has become one of the most successful procedures in orthopedics, and its survival rates are reportedly greater than 90% after 15 years.

Malpositioning of the component, however, can lead to various failures, such as aseptic loosening, instability, polyethylene wear, and patellar dislocation. Navigation systems for TKA have been developed to improve postoperative alignment. Many clinical and experimental studies of these navigation systems have shown that the accuracy of implanted components has improved.

We have compared the alignment of 150 total knee replacements implanted using a computed tomography-based navigation system and using the conventional alignment guide system when performed by a single surgeon. The knees were evaluated using full-length weight-bearing anteroposterior radiographs and computed tomography scans. For the navigated group, the average hip-knee-ankle angle, the femoral component angle to the femoral mechanical axis, and the tibial component angle to the mechanical tibial axis were 179.5, 89.4 and 89.7 degrees. The rotational femoral and tibial component angles to the planning axis were 0.6 and 0.3 degrees. The ideal angles of all alignments in the navigated group were obtained at significantly higher rates than in the conventional group. Our results demonstrated significant improvements in component positioning with CT-based navigation system, especially with respect to rotational alignment.

Recently, we established a new method for 3D reconstruction from postoperative CT images in order to accurately measure the alignment of the component relative to any designed plane. The results showed that the discrepancy between the two-dimensional and three-dimensional evaluations was 0.3 ± 1.8 (−2.7–3.4) degrees.

The coronal femoral angle for 36 knees (97.3%) and the coronal tibial angle for all the 37 knees (100%) were obtained within 3 degrees from the optimal angle. It is possible to measure the postoperative alignment for TKA more accurately on the basis of the defining plane. Three-dimensional analysis is necessary to evaluate the accuracy of the navigation system.

We conclude that navigation system is a very useful tool for achieving proper postoperative alignment. Controversy still exists regarding accuracy in rotational alignment with image-free navigation, but our results showed that CT-based system significantly improved accuracy of rotational alignment. We should keep using and improving the systems to establish more simplified and accurate systems.


H. Wook Kang Jun Bae Kim Suk Joo Lyu

Purpose: The purpose of the study is to measure the resected surface of femur of the Korean patients during total knee arthroplasty surgery and to compare these measurements with the dimensions of femoral implants in current use.

Materials and Methods: Morphometric data (7 parameters) were obtained in 500 cases of resected femur of the Korean patients who underwent total knee arthroplasties, and these data were compared with four current implants designs.

Results: The range of medial-lateral width at the given implant varies widely. The anterior width of the resected femur at the condyle is smaller than the widths of the most implants, creating an overhang. The medial-lateral width of the condyle at the level of transepicondylar line is wider than most of the present implants. However the widths of the resected posterior condyles were narrower at anterior-posterior alignment, causing overhang at the posterior condyles. We felt this will cause anterior tensioning at flexion and reduce the ability to flex further.

Conclusion: The shape of the femur in Korean knee is different from that of current TKR implants in use, which are based on the anthropometric data of Caucasians. Therefore new design, better suited to the morphometric measurements of Korean knee, is necessary. Though historically this mismatch of the implant was well tolerated, new design to better fit the measurement of Korean knee should be considered for functional enhancement such as range of motion, durability and function.


Fred Cushner

Introduction: Wound Hemearthrosis remains a major concern following TKA. This prospective study evaluates the use of a knotless interlocking suture system and its relationship to wound appearance and OR efficiency.

Methods: Two groups of patients undergoing TKA in our institution were evaluated using two different wound closure techniques. Group I consisted of twenty five patients who underwent standard closure using interrupted vicryl for the arthrotomy, deep fascia, superficial fascia, followed by staples. Group II consisted of twenty five patients who underwent closure using three separate running barbed sutures (Quill, Angiotech Inc)– first for the arthrotomy, followed by deep fascia, subcuticular and staples. We compared closure times, drain output and postoperative day to achieve zero wound drainage on the dressings.

Results: Closure times for Group II averaged 10 minutes faster than Group I. Drain output was decreased in the barbed suture cohort. Wounds achieved zero drainage, on average, one day sooner in Group II and no patients were returned to the OR for hematoma evacuation or arthrotomy disruption.

Conclusions: Use of this new technique for closure of TKA incisions can lead to faster operative times, lower drainage outputs and less immediate postoperative wound drainage. It appears that hemostasis is obtained quicker with the use of this barbed suture system while at the same time while maximizing OR efficiency.


GA Higgins J Tunggall P Kuzyk E Schemitsch JP Waddell

Posterior slope of the tibial component is an important factor in overall alignment of Total Knee Arthroplasty. The purpose of this study was to compare the accuracy and reproducibility of tibial bone cuts utilizing traditional extramedullary 0 degree and angled 5 degree cutting blocks, and computer aided navigation, in primary total knee arthroplasty.

We identified 3 groups of patients. Group one were primary total knees performed using an extramedullary 0 degree cutting block for posterior slope, group 2 were performed using an extramedullary 5 degree cutting block and the third group were performed with computer navigation. Patients in all 3 groups were age and sex matched. All operations were performed by residents or clinical fellows, under the supervision of the senior authors. Lateral digital radiographs were reviewed and posterior slope was determined in a standardized fashion. Two independent blinded researchers assessed the posterior slope using Siemens Magicweb software version VA42C_0206.

The average difference from the ideal posterior slope in navigated knees was lower than with non-navigated knees, however this was not significant (p=0.086). The average difference from the ideal posterior slope in computer navigated knees was 1.77 degrees (95% CI=1.28 to 2.26) compared to 2.37 degrees (95% CI=1.56 to 3.17) with the 5 degree cutting block and 2.70 degrees (95% CI=1.73 to 3.66) with the 0 degree block. No absolute significant difference was highlighted between the 3 groups using ANOVA testing (p=0.22).

All three techniques used to obtain ideal tibial slope were accurate. Accuracy was not increased by the use of computer navigation; however navigation resulted in less variation in outcome. The two jig based methods produced similar outcomes and either technique can be used successfully.


J.Y. Jenny

Revision total knee replacement (TKR) is a challenging procedure, especially because most of the standard bony and ligamentous landmarks used during primary TKR are lost due to the index implantation. One might also assume that the conventional instruments, which rely on visual or anatomical alignments or intra-or extramedullary rods, are associated with significant higher variation of the leg axis correction, especially in cases with significant bone loss which prevents to control the exact location of the usual, relevant landmarks. Navigation system might address this issue.

We are using an image-free system (ORTHOPILOT TM, AESCULAP, FRG) for routine implantation of primary TKR. The standard software was used for revision TKR. Registration of anatomic and cinematic data was performed with the index implant left in place. The components were then removed. New bone cuts as necessary were performed under the control of the navigation system. The size of the implants and their thickness was chosen after simulation of the residual laxities, and ligament balance was adapted to the simulation results.

The system did not allow navigation for intramedullary stem extensions and any bone filling which may have been required. 60 navigated cases were compared with 30 conventional cases.

We observed a significant improvement of all radiological items by navigated cases. Limb alignment was restored in 88% of the navigated cases and 73% of the conventional cases. The coronal orientation of the femoral component was acceptable in 92% of the navigated cases and 81% of the conventional cases. The coronal orientation of the tibial component was acceptable in 89% of the navigated cases and 73% of the conventional cases.

The sagittal orientation of the tibial component was acceptable in 87% of the navigated cases and 71% of the conventional cases. Overall, 78% of the implants were oriented satisfactorily for the four criteria for navigated cases, and only 58% for conventional cases.

The navigation system enables reaching the implantation goals for implant position in the large majority of cases, with a rate similar to that obtained for primary TKA.

The rate of optimally implanted prosthesis was significantly higher with navigation than with conventional technique. The navigation system is a useful aid for these often difficult operations, where the visual information is often misleading.


K.C. Bertin

Introduction: Gender specific total knee prostheses have been developed and one expected outcome of a prosthesis that fit normal anatomy better would be the need for fewer soft-tissue releases at the time of implantation. The purpose of this study was to report any change in the frequency of soft-tissue maneuvers between a standard versus a gender based TKA design.

Methods: Using the same surgical technique, 568 consecutive primary cruciate retaining TKAs were performed by the author. Only female patients are reported. 258 received a Standard design and 160 received a Gender TKA design. Both groups were statistically evaluated for diagnosis, height, weight, body mass index (BMI), knee alignment, range of motion (ROM), total Knee Society Score (KSS), and the KSS pain component score.

Intra-operative parameters including all soft-tissue releases and component sizes were recorded.

Results: There was a significant decrease in lateral retinacular release utilization (p < 0.001) and overall soft-tissue releases (p < 0.002) when using the Gender TKA. There was also a significant shift in the size of femoral components used away from smaller Standard TKA femoral components. (p < 0.001). There was no change in the use of the polyethylene insert thickness (p = 0.368).

Discussion: Acceptance of femoral component design limitations may adversely affect the outcome of primary TKA. The use of a prosthesis that better reproduces female anatomy decreased the need for soft tissue ‘adjustments’. Additionally a larger size of femoral components was used. This requires less bone resection and may lead to better knee kinematics with a more normal posterior femoral offset. It is concluded that this design change improves operative technique of total knee replacement by requiring fewer releases in female patients.


A. Masini G.E. Bellina

Several authors have reported that Computer-Assisted Surgery (CAS) can improve limb and prosthesis alignment and ligament balancing in total knee arthroplasty (TKA) and permit the use of a less invasive surgical procedure. This can have a positive impact on the time of recovery of patients. In order to evaluate the real impact on the final outcome of CAS in TKA, we conducted a prospective control study comparing the outcome of computer-assisted and conventional TKAs.

We analyzed 60 primary TKAs, randomly divided into two cohorts -group 1 = STD (standard instrumentation) and group 2 = CAS -over three consecutive years. Both cohorts included 30 cases, all affected by primary knee osteoarthritis. The same model of prosthesis was implanted in all cases, by one surgeon, using the same surgical technique. Two patients were bilateral: in both cases one side was treated with standard instrumentation and the other with CAS. We conducted a clinical evaluation at the pre-operative moment and at the consecutive Follow-Up (FU), using the American Knee Society Score (AKSS). We scored patient satisfaction using the Oxford and the Ranawat Center questionnaire. We also recorded the main intra-operative data, such as total blood loss, surgical time, tourniquet time, Range of Motion (ROM). Finally, we performed a radiological study analyzing the pre-operative and consecutive FU radiographs to obtain a quantitative evaluation of limb and prosthesis alignment.

The intra-operative blood loss was higher in patients of group STD, with an average difference of 127 ml, statistically significant (p = 0.0283). Component position was acceptable for all implants, but the mechanical axe error of the CAS group was (1.00 +/−0.20) degrees, significantly less than that of the STD group (2.10 +/−0.50) degrees. The mean coronal femoral alignment was 90.00 degrees (range, 89 −92 degrees) in the CAS group, and 91.00 degrees (range, 88 −93 degrees) in the STD group. The operating time of the CAS group was longer than that of the STD group, with an average time difference of 26 minutes, statistically significant [ P = 0.005]. The AKSS and the Oxford and the Ranawat Center questionnaire analysis revealed a faster rehabilitation and an earlier return to daily life activities in the CAS group, independent of the preoperative level of disability.

We conclude that the use of navigation in TKA increases accuracy in limb and implant alignment and improves the rehabilitation phase. By achieving more reliable artificial joint implantation, CAS can improve prosthesis duration and joint function. It, however, needs more operating time.


N. Takahira K. Uchiyama K. Fukushima T. Kawamura M. Uchino M. Itoman

On the basis of observations made in recent years, it can be inferred that the incidence of venous thromboembolism (VTE) in Japan is as high as that in Western countries.

Since 2007, the use of fondaparinux for the prophylaxis of VTE following lower-limb orthopedic surgery has been approved for Japanese patients. This study was performed with an aim to investigate the safety and efficacy of fondaparinux for the prevention of VTE following hip surgery in Japanese patients.

From June 2007 to August 2008, we evaluated 141 consecutive patients (148 hips; average age, 65.6) undergoing total hip replacement (THR), consisted of cementless minimally invasive surgery, and hip fracture surgery (HFS), consisted of open reduction and internal fixation or bipolar hemiarthroplasty. We mainly used 2.5 mg of fondaparinux for a period extending up to 14 days. We estimated the symptomatic VTE and asymptomatic deep-vein thrombosis (DVT) rates in patients by ultrasonography performed on preoperative and postoperative day 3. In addition, we evaluated the pre-operative and postoperative plasma D-dimer levels on days 3, 7, and 14.

We determined that both the preoperative and postoperative incidence of symptomatic VTE was 0%. A D-dimer value of 20 ug/ml or higher was not observed on preoperative days 3 and 7; however, this value was observed in 2 hips on postoperative day 14. The incidence of asymptomatic DVT was observed to be 0.8% preoperatively and 4% postoperatively. In particular, the corresponding value following HFS was observed to be 7.7% preoperatively. The incidence of the hemorrhagic event was observed to be 14.9%. Bleeding was mostly observed in the surgical and drainage areas. An overall major bleeding incidence of 0.7% (1 patient) was observed. The corresponding value in patients in whom the administration of fondaparinux was discontinued by day 14 was 18.9%.

The study results indicate that fondaparinux is useful in Japanese patients for the prevention of VTE following hip surgery. However, the administration of this drug should be accompanied by additional measures to prevent the associated side effect of bleeding.


N. Watanabe Y. Taneda H. Iguchi M. Kobayashi Y. Nagaya H. Goto M. Nozaki S. Murakami S. Hasegawa K Tawada T. Hirade T Otsuka

Dislocation following total hip arthroplasty is one of the most common complications, occurring in 1% to 5% of all cases. Several causes for dislocation have been suggested that

Mismatching of cup positioning and stem anteversion

Impingement between cup and neck of stem prosthesis.

Most often positioning of the stem is anatomically predetermined, while the orientation of the cup is much more flexible. Since July 2005, stem first method has been applied for all cases. During this method, canal preparation and stem trial was done first, and then cup orientation was determined according to the stem direction and impingement. For the bigger cups 34mm or 38mm heads were applied in this series. In the present study dislocation ratio was compared to cup first method.

In the stem fist group (SF), the following procedures were done consequently.

Canal was prepared for the stem. Revelation lateral flare high proximal load transfer stem (DJO) was mainly selected. But for the case with high anteversion over 50 degrees, Modulas; conical distal load transfer stem with modular neck (Lima) was selected.

According to the stem anteversion and neck length, cup position and orientation were determined. (For the cases with higher anteversion, less cup anteversion was selected, and for some cases higher cup position was selected.

According to the cup size 28, 34, or 38 mm diameter neck was selected.

From October 2002 to July 2008, there were 191 THA cases. There were 81 hips in Standard group and 109 hips in SF group. There were 63 females and 18 males in Standard group and 90 females and 19 males in SF group (p=0.41). Average age was 61.0(22–81) in Standard group and 60.2(29–89) in SF group (p=0.53). In Standard group, 64 were replaced for osteoarthritis, 15 for rheumatoid arthritis and two for avascular necrosis. In SF group, 86 were replaced for osteoarthritis, 17 for rheumatoid arthritis and six for avascular necrosis (p=0.53). As for Crowe’s classification, 61 type I, 18 type II and 2 type III were included in Standard group. And 88 type I, 15type II, 4 type III and 2 type IV were included in SF group (p=0.29). Average anteversion of femoral neck were 23.1(−2 to 70) degree in Standard group and 26.2(−4 to 65) degree in SF group measured with CAT scan (p=0.274). MoM bearing surfaces were used with 71 hips (87.7%) in Standard group and 100 hips (91.7%) in SF group (p=0.35). Only in SF group, big metal head were used in 24hips(22%) with 34mm and in 12hips(11%) as 38mm diameter. Average leg length difference between pre and post operation was 11.5mm(0 to 36) in Standard group and 8.0mm(−18 to 30) in SF group (p< 0.05). Average cup inclination was 43.2(25 to 84) degree in Standard group and 40.9 (22 to 66) degree in SF group (p< 0.05). Average cup anteversion was 8.2 degree (0 to 22.8) in Standard group and 7.1 degree (−12 to 30.5) in SF group (p< 0.05). Average operating time was 111.9min (67–150) in Standard group and 97.5min(60–162) in SF group (p< 0.05). Average intra operative hemorrhage was 744ml(10–2757) in Standard group and 487ml(10–1374) in SF group (p< 0.05). The dislocation rate was decreased from 3.7% (3/81 cases) in Standard group to 0.0% (0/109) in SF group.

In conclusion our study suggested that Stem first method and utilization of big metal head would decrease the dislocation rate in primary cases. More bleeding from canal during accetabular reaming was expected. However less bleeding was observed in SF group.


L. Puri R.R. Shah G. Strohmeyer Lalit Puri

Computer Assisted Total Knee Arthroplasty (CAS TKR) has been shown to provide excellent and reproducible limb mechanical alignment. CAS TKR has also been demonstrated to reduce limb alignment variance and outliers. Previous studies have shown improved mechanical alignment both radiographically and clinically. Specifically, CAS TKR has been shown to result in alignment deviations less than 3 degrees from neutral mechanical femoral and tibial axes. Furthermore, CAS TKR also permits any significant pre-operative tibial deformity to be quantified prior to performing tibial osteotomies. In this study, we describe the use of computer navigation to quantify the amount of bone loss on the medial or lateral tibial plateau and the subsequent use of this data to assess the need for augmentation with tibial wedges.

Two hundred and thirty consecutive primary computer assisted total knee arthroplasties were performed by one senior surgeon (L.P.) at Northwestern Memorial Hospital. In all cases, the tibial deformity was quantified and recorded intraoperatively using computer navigation software. The deformity was recorded in the navigation software by inputting the lowest point on the deformed tibial plateau and the mid point on the non-deformed tibial plateau using navigation markers. After Institutional Review Board approval was obtained, a retrospective review of the patient operative reports and patient charts was performed. Operative reports were reviewed to identify cases with the difference between the values of medial and lateral tibial plateaus exceeded thirteen millimeters and cases when tibial augmentation was performed. In cases utilising medial or lateral tibial augmentation, pre operative and post operative anterior posterior and lateral knee radiographs and long leg standing anterior posterior radiographs were reviewed to measure the joint line restoration and final mechanical limb alignment.

All two hundred and thirty operative dictations and patient charts were reviewed. In seven cases, the difference between the values of the medial and lateral tibial plateaus was greater than thirteen millimeters. In all seven cases, tibial augmentation was utilized in order to prevent resection of tibial bone in excess of fourteen millimeters. In cases with a difference of medial and lateral tibial plateau values of less than thirteen millimeters, no tibial augmentation was utilised. For the seven cases using tibial augmentation, preoperative and post-operative knee and long standing radiographs were reviewed to examine joint line restoration and final limb alignment. In all seven patients, joint line restoration was successful within 4 millimeters and long standing radiographs revealed excellent limb alignment.

Computer Assisted Total Knee Arthroplasty has already been shown to provide excellent limb alignment and reduce variance and outliers. We demonstrate that Computer Assisted Total Knee Arthroplasty in patients with significant tibial deformities can help assess and the amount of bone loss on the medial or lateral tibial plateaus. Excessive tibial resection to restore the mechanical axis and joint line can be avoided by quantifying the amount of tibial bone loss prior to osteotomy. Thus, Computer Assisted Total Knee Arthroplasty can successfully restore the joint line and overall limb alignment with conservative bone resection in patients with significant pre-operative tibial deformities.


K. Kanesaki K. Yokosuka Y. Mitsui T. Kaieda K. Nagata

We have been operating TKA for the deformity of OA and RA knee using OrthoPilot kinematic navigation system manufactured by Aesculap (Germany, Tutulingen) since 2005. It has the technology of ligament balance check capability, of which intra-operative registration is not so troublesome and also has the guidance system to achieve the correct bony cutting to the mechanical axis. Although we only have short-term results so far, we have evaluated our results and made some observations.

We have 151 cases at our institution composed of 114 OAs and 37 RAs, with 29 males and 122 females. Among them, 95 cases were able to follow-up over one year.

Limited only to three cases, we had to discontinue the usage of this system due to the loosening of the rigid body during surgery, which we had to change the maneuver to use manual instrument.

The average age at the time of surgery was 73.8 years (range, 38 to 90), and the average BMI was 24.5 (range, 15.6 to 37.7). The average femoral axis, which is the angle between the femoral mechanical axis and the femoral joint surface in the coronal plane, was 2.06 degrees (range, −9 to 10). The average pre-bone-cutting tibiofemoral axis was −8.04 degrees (range, −31 to 15), which after implantation became −0.18 degrees (range, −6 to 6). Tibial proximal cutting has to be perpendicular to the mechanical axis of the lower leg in the coronal plane. The average tibial medial cut was 1.61mm (range, 8 to −11) and tibial lateral cut was 6.78mm (range, 15 to −2). This difference of about 5mm indicates that the shape of tibia had varus deformity to the mechanical axis of the lower leg. On the femoral side, the average femoral medial cut was 9.72mm (range, 19 to 1) and femoral lateral cut was 8.23mm (range, 16 to 1). This almost identical cutting thickness indicates that there was almost no deformity to the mechanical axis on the femoral side. The final X-ray in the follow up period had not changed from the post-operative one. There was no change in VAS comparison three months post-operative.

The results of this study seem to indicate that the kinematic navigation system for TKA will lead to good results of patients’ satisfaction and long durability even for OA and RA knees.


D. Hamada Y. Okubo K. Yamamoto S. Mori K. Ikeuchi N. Tomita

It have been reported that the wear volume of vitamin E-containing UHMWPE tested with a knee joint simulator was approximately 30% lower than that of virgin UHMWPE at 5 million cycles. However, the wear resistance mechanism of vitamin E-containing UHMWPE has not yet been clarified. The present study examines the effects of the addition of vitamin E on the frictional properties of ultra-high molecular weight polyethylene (UHMWPE) under several different load and serum conditions.

Friction tests were carried out using a computer-controlled pin-on-disk friction test apparatus. The UHMWPE pin was mounted vertically at the tip of the leaf spring and linear reciprocating sliding motion for 2,000 cycles with an amplitude of 1 mm and a frequency of 1 Hz, was applied under 3 MPa or 30 MPa loading against Co-28Cr-6Mo alloy disk. The lubricant bath was filled with 5 ml of ultrapure water, fresh serum, post-friction (PF) serum or diluted-PF (DPF) which were kept at a temperature of 37°C. The friction force between the UHMWPE pin and the Co-28Cr-6Mo alloy disk was calculated from the displacement of the leaf spring during the sliding motion.

Vitamin E-containing UHMWPE showed a significantly higher friction force than that of virgin UHMWPE in fresh serum lubricant at 30 MPa loading, while there were little differences in either ultrapure water or PF serum or DPF serum. And vitamin E-containing UHMWPE tends to exhibit a lower dynamic friction force within the first few hundred cycles in the case of all serum lubricants at 30 MPa loading. These results suggest that some interaction between the UHMWPE surface and the native conformation proteins was specifically affected by the addition of vitamin E and that some weeping of vitamin E might occur at early stage of sliding. Our results also suggest the importance of the conformational changes of serum proteins for the wear testing.


T. Yamamoto K. Uchiyama H.J. Park N. Takahira K. Fukushima M. Suto K. Suto K. Urabe M. Itoman

In recent years, the progressive technology of hemodialysis provides long-term survival for renal failure patients. On the other hand, avascular necrosis of the femoral head from the use of steroids or renal osteodystorophy or femoral neck fracture due to amyloid arthropathy have increased. In such cases, bipolar femoral head prosthesis (FHP) and total hip replacement (THR) are usually performed. But it is at risk of developing severe complications, such as early loosening or infection of the implant.

The aim of this study is to evaluate the stability of the cementless stems in radiograms and clinical results after FHP or THR using three types cementless prosthesis in hemodialysis patients.

The study included 14 patients (19 hips) on hemodialysis who underwent FHP or THR using three types cementless prosthesis at our institution between 1983 to 2005 and we could follow up at least two years. There were 8 women (11 hips) and 6 men (8 hips) with an average age of 43.9 years (range, 20–88). The average follow-up was 6.75 years. The average hemodialysis term was 10.5 years. Three types of hip prosthesis (7 stems were CLS, 6 stems were IMC, 6 stems were Duetto S-I) has been used for the treatment at our institution in the past. The initial diagnosis was avascular necrosis of the femoral head in 8 hips, femoral neck fracture in 5, osteoarthritis in 4 and amyloid arthropathy in two. We assessed at least 3° of varus-valgus deviation or at least 3 mm of subsidence as aseptic loosening of stems, and assessed radiolucent line and stress shielding of the stems in radiograms, also. As for clinical results, we measured postoperative infection rate and revision rate.

Aseptic loosening of stems were identified in 3 hips (15.8%). Radiolucent lines were identified in 5%–26% of hips categolised by Gruen’s classification zone I-VII, although their zones differed according to the stem model. Stress shieldings were identified in 10 hips (53%), most of which were level 1, according to the criteria described by Engh et al. Infection rate and revision rate were 5.3% (1 hip) and it was a long-term hemodialysis patient.

Several studies report, there is a high probability that early loosening of the stems is associated with amyloid deposition. We experienced early loosening of the stems in our case and considered prevention of amyloid deposition very important in improving the prognosis of the arthroplasty. We must follow carefully hemodialysis patients after an operation because their nutrition level is low and their bodies are compromised due to steroids use and their postoperative infection rate is high.


A. Moroni B. Wippermann W. Siebert S. Mai G. Micera R. Orsini M. Hoque S. Giannini

Although the number of displaced femoral neck fractures treated with hip arthroplasty is steadily growing, the outcomes are not as good as for other surgical indications. As a result, there is no consensus on the ideal type of arthroplasty for these patients. Unipolar and bipolar arthroplasty have a low dislocation rate but implant longevity and functional results are suboptimal. Total hip arthroplasty (THA) provides better functional outcomes and implant longevity but it is associated with a high incidence of postoperative dislocation. This constitutes a significant limiting factor for a more widespread use of this procedure.

The TriboFit® Buffer (Active Implants Corporation, Memphis, Tennessee, USA) is a 2.7 mm-thick cup made of polycarbonate-urethane which mimics the mechanical characteristics of human cartilage. It is a pliable, hydrophilic, biocompatible, endotoxin-resistant material and acts as a stress-absorber, transmitting loads to the subchondral bone in a physiological manner. The TriboFit® Buffer shows excellent tribology, including ideal fluid film lubrication, low friction, high load carrying capabilities and long endurance.

The TriboFit® Buffer is fixed using flexible mechanical fixation. With a special instrument, a circumferential groove is cut into the patients’ socket. The TriboFit® Buffer is seated by applying gentle pressure, with its ledge snapping tightly into the groove. The surgical technique is bone sparing as no acetabular bone reaming is required whatsoever. The TriboFit® Buffer can be coupled with large diameter cobalt-chromium femoral prosthetic heads of the same dimensions as the patients’ femoral head. By restoring the correct hip anatomy and preserving the original size of the femoral head, hip range of motion (ROM) and stability are optimised.

Within a multi-centre study, 224 patients (63 male and 161 female) with femoral neck fractures were treated with the TriboFit® Buffer, a large diameter head and either cemented (192) or uncemented femoral stems (32). The mean patient age was 83 years (range 65 to 96).

All surgeries were performed using a standard antero-lateral approach.

Rehabilitation was fast and weight-bearing was as tolerated by the patients. There were no major complications, and in particular, no postoperative dislocations were reported.

At a mean follow-up of one year, X-rays showed good implant stability. The mean Harris hip score (HHS) after one month was 58 points and increased to 80 points at one year (p = < 0.05). The ROM was the same as in the intact hip. Only one patient was revised because of nonimplant-related pain. This patient complained of pain in the surgically treated limb which was in actual fact related to spinal stenosis. Analysis of the retrieved implant revealed a loss of thickness in the superior area as well as minimal weight (approximately 2.4%). The backside revealed evidence of macroscopic wear in the area of directional loading from the femoral head to the acetabulum. The bearing surface showed minimal wear (less than 15 mm3), indicating that the primary wear location was on the backside. Retrieved synovial fluid and tissue analysis confirmed that there was no reactivity and no sign of synovitis.

With femoral neck fracture patients, TriboFit® Buffer arthroplasty is theoretically superior to both hemiarthroplasty and THA as it should involve the same low risk of dislocation and acetabular bone preservation associated with hemiarthroplasty, together with the same good functional results and consistent implant longevity of THA. Other advantages of this technique include reduced bleeding and short surgical times.

The results of this study show that the new TriboFit® Buffer arthroplasty technology has the potential to revolutionize the surgical treatment of displaced femoral neck fracture.


Michael Swank

Introduction: Much debate exists regarding sparing or sacrificing the posterior cruciate ligament (PCL). The posterior cruciate ligament is said to maintain proprioception and stabilization post knee arthroplasty. Substitution of the PCL can require more femoral bone resection, but is thought to improve range of motion. Release of the PCL can restore extension and enhance flexion through greater femoral rollback. Bicruciate implants potentially offer greater flexion and enhanced stability. Each implant design with mechanical instruments requires a different surgical technique making it difficult to directly compare the patient and surgical outcomes. Computer navigation eliminates the differences in implantation between the various implant designs and theoretically allows a more direct comparison of implants based on design characteristics and not surgical technique. The purpose of this paper is to review four different implant designs implanted by a single surgeon with a computer assisted, gap balancing technique to determine if there was any difference in patient outcome.

Methods: A total of 504 implants consisting of posterior cruciate sparing (PFC-RP), PCL substituting (PFC-RPC), PCL sacrificing (LCS) and bicruciate (Journey) implants performed by a single surgeon were reviewed. The PFC-RP group (260) was the largest, followed by the LCS (124), the PFC-RPF (80) and the Journey Knee (40). Outcomes reviewed were range of motion, function, pain and radiographic data to include alignment and evidence of radiolucency.

Results: Demographic data of groups compared included 175 men and 329 women. Mean ages ranged from 61 to 74 years. Preoperative scores among all groups were similar with the cruciate substituting group slightly lower in function, flexion and with more pain before surgery. Overall function improved across all groups through two years, with better scores in the Journey and LCS implants (77 and 73 points) versus RPF (47) and PFC retaining group at (68) at one year (A perfect score is 100). Flexion values were comparable between all groups at one and two year intervals with Journey the highest mean flexion (116 degrees) at one year and with the PFC-RP offering the highest mean flexion at the two year mark (115 degrees). The RPF group at the one year mark had more pain overall (28) versus the other three groups (Journey 45, LCS 42, Sigma RP 45). No patients in any group were revised for instability. Other surgical complications were equal in each group.

Discussion: While the PCL substituting knee patients (PFC-RPF) had lower pain, function and flexion at 12 months compared to all other groups, they started with lower overall knee scores. After accounting for the differences in patients preoperatively, no difference could be found between implant designs when implanted with a similar surgical technique employing a computer assisted gap balancing protocol.


H.E. Cates M.A. Schmidt R.D. Komistek

This research is to relate functional outcomes to kinematics in high flexion CR and PS total knees by using the Total Knee Function Questionnaire in patients who had previously undergone kinematic analyses.

Patients were identified who had primary total knee arthroplasty and had undergone kinematic analyses using fluoroscopy. The Total Knee Function Questionnaire was sent to these patients, and data was obtained for 14 CR knees (NexGen CR-Flex, Zimmer) and for 13 PS knees (Legacy LPS-Flex, Zimmer). The questionnaire evaluates baseline activities of daily living, advanced activities, and recreational activities and exercises.

CR patients reported higher satisfaction and that their knees felt more “normal” than PS patients. Some baseline activity scores were significantly higher for CR than for PS knees.

Limitations in baseline activities were related to kinematic constraints, including flexion, lateral and medial anterior-posterior (A-P) translations, and tibiofemoral axial rotation. Kinematic data were related to difficulty data for advanced and recreational activities of kneeling, squatting, gardening, and stretching.

Comparisons between kinematic data and patient feedback on knee function provided unique information about differences between CR and PS high flexion implants. CR patients had better function than PS patients in walking on even ground or uphill or sitting. CR patients had higher activity scores for recreational than for advanced activities, while activity scores for the PS patients were similar between these activities. Kinematic variables that affected function for some activities included extremes of flexion, A-P translations of lateral and medial condyles, and axial rotation intervals.


A.V. Lombardi K.R. Berend J.B. Adams

Surgeons theorize smaller increments in sizing might better address different sized femurs and size differences between genders. This study examines utilisation of intermediate sized components to determine if availability affects outcomes of women and men undergoing total knee arthroplasty (TKA).

We reviewed 1903 consecutive, primary TKA in 1519 patients (64% women) performed with a single implant system. Originally, six femoral sizes were available; four intermediate sizes were added later. The system allows interchange ability of all femoral and tibial sizes and has seven constraint options. Four hundred and five TKA were done prior to intermediate size availability. In women before, 49% were 65mm, 47% 60mm, and 3% 70mm. After, 32% were 62.5mm, 21% 65mm and 8% 67.5mm. In men, 70mm was the most common representing 49% before and 41% after. The 65mm in men dropped from 29% before to 16% after and the 75mm dropped from 21% to 14%. After, 23% were 67.5mm. Minimum follow-up was two years.

When comparing women before versus after, women after had significantly better postoperative Knee Society (KS) pain (p=0.0000), clinical (p=0.003) and function scores (p=0.0000), and improvement in clinical (p=0.0000) and function scores (p=0.0001) while improvement in pain score was similar. Men done after had better postoperative KS pain (p=0.02) and function scores (p=0.002), and improvement in KS clinical (p=0.001) and function (p=0.0002) scores.

Both men and women undergoing TKA after availability of half sizes had better postoperative KS pain, clinical and functional scores, and improvement from preoperative levels compared with men and women before. We conclude a single TKA system with a wide variety of sizing and constraint options can provide consistently excellent results for both men and women undergoing TKA.


J.S. Shields T. M. Seyler C. M. Maguire R. H. Jinnah

Hip resurfacing arthroplasty is a technically challenging procedure, and orientation of the femoral component is critical to avoid implant failure. Recently, numerous articles have shown that the use of computer-assisted navigation decreases the learning curve for beginners in hip resurfacing and to improve the surgeon’s ability to produce consistent results. The purpose of this study was to evaluate the learning curve of computer-assisted navigation in the hands of an experienced hip resurfacing surgeon.

This retrospective study was compromised of 100 metal-on-metal total hip resurfacings in 94 patients. The resurfacings were performed by a single fellowship-trained surgeon, with hip resurfacing experience of more than 250 hip resurfacings without navigation. Data collected included gender, age at the time of surgery, BMI, operative time, postoperative complications, and digital planning. Standard nteroposterior (AP) radiographs taken in the preoperative and postoperative period were evaluated to measure neck-shaft and stem-shaft angles, respectively. There were 24 females and 70 males, who had a mean age of 49 years (range, 19 to 68 years). The 100 hips were arranged chronologically by operative date and broken down into four groups of 25. Data also was gathered on 25 non-navigated hip resurfacings to serve as a matching group.

There were no significant differences found between the four groups and matching groups with respect to patient variables, including age, BMI, or gender. There were also no significant differences found among the groups with respect to OR time (p = 0.565). The mean OR time for all 100 navigated hips was 101 minutes, compared to a mean of 104 minutes for the matching group (p = 0.924). Using linear regression analysis, the only variable that was found to influence OR time was BMI (p < 0.001). The mean actual stem-shaft angle (SSA) of the groups became more valgus over time, with group 1 having an SSA of 139; group 2, an SSA of 140; group 3, an SSA of 142; and group 4, an SSA of 144. Compared to the preoperative neck-shaft angle, the postoperative stem-shaft angle for 89% of the femoral components was inserted in a valgus position, with 96% of those in group 4 being inserted in a valgus position. The matching non-navigated group had only 80% of the cases with the stem-shaft angle inserted in valgus.

The data presented here demonstrates that providing an imageless computer-assisted navigation system to an experienced hip resurfacing surgeon offered the benefits of navigated surgery including increased accuracy, with no learning curve effect. Computer-assisted navigation can help the learning curve of a technically demanding procedure in inexperienced surgeons, as described by the literature, while placing real-time feedback and consistent repeatability into the hands of an experienced surgeon.


Sebastien Parratte Pascal Kilian Thomas Lecorroller Vanessa Pauly Pierre Champsaur Jean-Noël Argenson

Most of computer-assisted computer assisted system rely on the peri-operative acquisition of the anterior pelvic plane defined as the plane crossing the two anterior iliac spine and the symphysis. The goal of this study was to evaluate in vivo and in vitro the accuracy of the anterior pelvic plane acquisition, considered as the reference for computer-assisted total hip arthroplasty (THA).

Cup placement was performed using an imageless computer-assisted system in thirty patients during THA. Post-operatively the position of the cup was evaluated on computed tomography using a validated tridimensional software. The differences between the perioperative and postoperative angles for abduction and anteversion were compared using a two-group pair test.

On two cadavers four clinicians performed ten times the anterior pelvic plane acquisition using three Methods: percutaneously, with ultrasound and by direct bony acquisition defined as the reference. The mean error for each anterior pelvic plane acquisition method was compared using a univariate variance model for repeated measurements.

In vivo, the mean difference between the perioperative and postoperative abduction angles was 4° and not statistically significant. For anteversion, the difference was 4° and not significant in patients with BMI < 27. The difference was 11° and significant in patients with BMI > 27 (p< 0.001). In vitro, the mean errors for rotation and tilt were respectively 3.8 ° and 19.25 ° for cutaneous acquisition, 2.8° and 6.2° for ultrasound acquisition method. The errors were statistically higher with the percutaneous method (p< 0.001).

According to our results, the accuracy of the standard percutaneous acquisition method of the anterior pelvic plane in computer-assisted THA is limited. The ultrasound acquisition method may represent a reliable alternative.


R. Mootanah H.J. Hillstrom A.M. New C. Imhauser R. Walker K. Cheah E. Blanc S. Mangeot C. Daré C. Mouton A. Burton S. Ait Ali J. Dowell

14.1% of men & 22.8% of women over 45 years show symptoms of osteoarthritis OA of the knee [1]. Knee OA is usually associated with lower limb malalignment [2]; 50 of varus results in 70% −90% increase in compressive loading of the medial tibio-femoral compartment [3] and OA worsening over 18 months [4]. High Tibial Osteotomy (HTO) enables preservation of bone stock and soft tissue structures and could be an attractive option to younger patients who wish to return to high level activity. However, results of HTOs are unpredictable, which could be due to patient selection or surgical techniques. The long-term aim of this work is to develop a predictive tool to aid the surgeon in the selection of optimal HTO geometry for improved and more consistent surgical outcomes. The first step in achieving our longterm goal was to determine whether stress predictions at the tibio-femoral articulation were sensitive to simulated high tibial osteotomy, using finite element (FE) method.

CT and MRI data of a cadaveric knee were used to create geometrically accurate 3D models of the femur, tibia, fibula, menisci and cartilage and tendon of the knee joint, using the Mimics V12.11 commercially-available software (Materialise, Belgium). The Simulation module was used to register the bones and the soft tissues. The resulting STL files were exported to CATIA V5R18 pre-processor to generate surface meshes and create the corresponding 3D solid and FE models of the osseous and soft tissues from the STL cloud of points.

The Young’s moduli for cortical bone, cancellous bone, cartilages, menisci and ligaments were taken from literature as 17 GPa, 500 MPa, 12 MPa, 60 Mpa and 1.72 MPa respectively [5,6,7]. The Poisson’s ratios for osseous and soft tissues were taken as 0.3 and 0.45, respectively [8]. The nodes between the bones and the corresponding cartilages were merged and surface contact was applied between the cartilages. The distal ends of the tibia and fibula were fixed and a load of 2.1 KN, corresponding to 3 x body weight, was applied perpendicularly to the proximal end of the femur. Results of finite element analyses show a reduction of 67 % in principal stresses in the knee joint following an open wedge HTO surgery simulating 100 varus correction.

FE analysis results of this study show that HTO reduces stresses in specific regions of the knee, which are associated with OA progression [4]. Our future works include corroborating our results with controlled cadaveric experiments and implementing optimization techniques to predict optimum HTO geometries for patient-specific FE models.


K. Tei T. Matsumoto S. Kubo K. Sasaki K. Ishida N. Shibanuma H. Muratsu M. Kurosaka R. Kuroda

Recently, many researches of minimal incision surgery (MIS) total knee arthroplasty (TKA) have been reported, however very few of these contain clinical results. Regardless of this, MIS TKA is widely promoted as an improvement over traditional TKA. Although traditional TKA allows for excellent visualization, component orientation, fixation, and has been associated with remarkable long-term implant survival, many patients expect an extremely small incision, minimal or no pain and discomfort associated with their surgery, and certainly no increase in the complication rate. While there is some evidence that short term benefits may occur, there is concern that there may be an increase in complications with the use of MIS technique. We report here cases that malalignments in early phase were occurred after MIS TKAs. A consecutive series of MIS TKA for varus osteoarthritis undertaken by 2 surgeons at 2 centers during 2-year priod (2006–2007) was reviewed. During this interval, 50 MIS TKAs were performed. The mean age was 75.6 years (range 54 to 88 years). Cases for post-operatively infection were excluded. There were 2 cases that early failures due to varus sinking of tibial component were confirmed in early phase (7 and 3 months after primary surgery). We analyzed data between early failed cases and non-failed cases. Patients with early failure were younger, which showed a trend toward significance (p=0.11; failed; 66.5, non-failed; 75.9 years). There was no difference in amount of both medial and lateral side of distal femoral cut between early failed cases and non-failed cases. Proximal tibial cut was significantly larger in early failed cases compared with non-failed cases (p=0.01; failed; 16.5±4.5, nonfailed; 11.4±6.6). There was no difference in Femorotibial angle (FTA) after surgery between them. Substantial backgrounds of occurring early failure after MIS TKA are not still clarified, however, very early failure were occurred in patients, who had significant large cut of proximal tibia, in our experienced cases. MIS TKA may lead to varus imbalance due to increased amount of bony cut and decreased medial soft tissue release. Henceforth, the high prevalence of MIS failures occurring in early phase is disturbing, because of limited working space and warrants further investigation.


N. Okamoto L. Breslauer A.K. Hedley S.A. Banks

Total knee arthroplasty (TKA) increasingly is utilized to treat younger, more physically active, or more culturally diverse patients who desire the ability to perform activities with high knee flexion. As a result, many implant manufacturers have modified designs or introduced new ones to better facilitate deep knee flexion. To date, a mix of studies has reported superior or equivalent flexion performance comparing high-flexion and traditional implant designs. Importantly, many of these studies are conducted with the patient supine in non-weightbearing postures, not in functional postures where differences in joint mechanics are better manifest. The goal of this study was to evaluate weightbearing kneeling and lunging knee kinematics in patients with bilateral TKA of two types.

Nine high functioning patients from the American Southwest provided informed consent to participate in this single-surgeon study. The subjects averaged 74 years of age and included three females. Each subject received a traditional cruciate-retaining TKA in one knee and a flexion-enhanced cruciate-retaining (7 knees) or posterior-stabilized (2 knees) TKA in the other. The traditional knees were an average of 84 months postoperative and had combined Knee Society Scores averaging 183. The knees with new TKA designs were an average of 31 months postoperative and had combined Knee Society scores averaging 188. Subjects were observed performing a weight-bearing lunge to maximum comfortable flexion and partially weightbearing kneeling to maximum comfortable flexion using lateral fluoroscopy. Model-image registration techniques were used to quantify the 3D translations and rotations of the tibial and femoral components.

There were no differences in maximum knee flexion during lunging (115°±12° versus 118°±7°) or kneeling (120°±14° versus 120°±10°) for the traditional and flex-ionenhanced TKA’s. Tibial internal rotation and abduction were not different. The locations of the medial and lateral condyles were significantly more posterior in the traditional design for both activities (p< 0.05).

This study examined maximum flexion knee kinematics in clinically excellent, high performing subjects with bilateral TKA of two types. No clinically important functional differences were observed. Although flexion-enhanced designs may provide improved flexion for patients who demand it, older patients living a Western lifestyle appear to do equally well with the traditional and flexion-enhanced TKA designs.


D. Giddings J. J. Wu I. Khan A. Unsworth

Artificial hip joints have been in use for a number of years; various combinations of metals and polymers have been tested both in vitro and in vivo. Modern ceramics have found application as bearings in hip replacement due to the enhanced wear and friction that they offer. It has been hypothesised that during the swing phase of gait it is possible for the Femoral head and the Acetabular cup to dislocate, before relocating during heel contact.

Severe loading such as this could cause greater levels of wear to occur in artificial hip joints.

This study provides comparative analysis between ceramic-on-ceramic hip joint pairings under both severe and standard loading profiles.

Five zirconia-toughened alumina (ZTA) 28mm diameter bearing pairs were tested on a ProSim Hip Simulator for 5.3 million cycles (MC), two under severe loading and three under standard loading conditions. Additionally a Loaded Soak Control, Soak Control and Environmental Control were used. Wear was recorded every 0.5 MC by gravimetric measurement. Surface microscopy images from a Zygo New View 100 and an Atomic Force Microscope (AFM) were taken before testing and then at, 0.5 MC. 2.5 MC, and 5.3 MC.

The standard loading profile followed ISO14242-1 standard with 2650±50N maximum force, ±10° internal-external rotation and −15–30° flexion-extension. To simulate aggressive wear condition, microseparation inferiorly and micro-lateralisation laterally were applied during the swing phase. Dual acting cylinders were used to apply a constant force of 350±50N in opposition to the standard loading profile to enable separation between the Femoral Head and the Acetabular Cup during the swing phase. This microseparation was measured by means of a Linear Variable Differential Transformer (LVDT) and the setting gave a reading of 1.2mm ± 0.1mm at the start of each 0.5 million run. The value for microlateralisation was 0.9mm whilst the inferior separation was 1.2mm.

Wear rates for the ceramic cups under severe wear condition were found to be 0.0356±0.0059mm3/ MC and for the standard wear condition to be 0.0178±0.0049mm3/MC.

The femoral heads had wear rates of 0.0164±0.0046mm3/MC for severe wear condition and no wear was detected for the standard wear condition.

The results of the present study showed almost no wear under standard gait condition and only a modest increase in wear occurred when using severe wear condition. Thus the resulting wear rates are still significantly lower than those found for alumina-alumina total hip joints [1, 2].


A. Mullaji G.M. Shetty

Total knee arthroplasty becomes more challenging when knee arthritis is associated with an extra-articular deformity of the femur or tibia. We evaluated the outcome of navigated total knee arthroplasty in a large series of arthritic knees with extra-articular deformity.

We retrospectively reviewed the records of 950 patients who had undergone navigated TKA between January 2005 and February 2008. There were 40 extra-articular deformities in 34 patients, with bilateral involvement in 6 patients which were included in the study. Twenty-two limbs had deformity in the femur and the tibia had deformity in 18 limbs. There were 24 females and 10 males with a mean age of 63.1 years (range, 46–80 years).

The etiologies included malunited fractures (13 patients), stress fractures (4 patients), post high tibial osteotomy (3 patients), and excessive coronal bowing (14 patients). The mean femoral extra-articular deformity in the coronal plane was 9.3° varus (range, 24° varus to 2.8° varus) and the mean tibial extra-articular deformity in the coronal plane was 6.3° varus (range, 20° varus to 8.5° valgus). Three limbs underwent simultaneous corrective osteotomy and the rest were treated with intra-articular correction during computer-assisted total knee arthroplasty. The limb alignment changed from a mean of 166.7° preoperatively to 179.1° postoperatively. At a mean follow-up of 26.4 months, the Knee Society knee score improved from a mean pre-operative score of 49.7 points to 90.4 points postoperatively; function score improved from 47.3 points to 84.9 points.

The results of our study indicate that computer-assisted total knee arthroplasty is a useful alternative to conventional total knee arthroplasty for knee arthritis with extraarticular deformity where accurate restoration of limb alignment may be challenging due to the presence of a deformed tibia or femur or in the presence of hardware.


Rajeev K Sharma Yuvraj Kumar Rakesh Kumar Saurabh Agarwal

Fixed flexion deformity is common in neglected cases of advanced arthritis of the knee.

The need and means of complete correction of fixed flexion deformity remains controversial. We analysed 60 patients of advanced arthritis with severe flexion deformity > 300 who underwent total knee arthroplasty between January 2002 to January 2008. The age ranged from 54 to 78 years (mean age of 62 years). All surgeries were performed using posterior cruciate substituting implant. Patients were followed for an average period of 42 months.

All patients were operated in a single stage. Distal femoral over-resection was done in addition to posterior, postero-medial and postero-lateral release. Posterior release was done upto the linea aspera. In 2 cases posterior capsular was released directly. A criteria was developed for sequential release on the basis of degree of flexion deformity.

Flexion deformity was fully corrected in 48 cases where as 50 of residual flexion remained in 5 cases with preoperative deformity of 40–600 and 100 residual flexion remained in 6 cases with preoperative deformity > 600. One patient with pre op fixed flexion deformity of 90* had to be treated with arthrodesis.

Our experience suggest that predetermined routine femoral over-resection in moderate to severe flexion deformity prior to balancing knee is not fraught with complications if our criteria are followed. Additional bony cuts (over-resection) and posterior soft tissue release is complementary to each other in correction of flexion deformity and it should be a sequential release. This technique saves time, reduces intraoperative difficulties and helps to correct flexion deformity maximally.


D.A. Glaser D.A. Dennis R.D. Komistek S.J. Deaderick M.R. Mahfouz

In vivo kinematic analyses of total hip arthroplasty (THA) have determined femoral head separation from the medial aspect of the acetabular component can occur. Various bearing materials are currently used in THA today. The objective of this study was to determine if differences in the incidence and magnitude of femoral head separation exist among various bearing surfaces for THA during different weight-bearing activities.

205 clinically successful subjects implanted with either metal-on-metal (MOM), metalon-polyethylene (MOP), ceramic-on-ceramic (COC) or ceramic-on-polyethylene (COP) materials were analyzed using video-fluoroscopy. Each patient performed either gait on a treadmill or an abduction-adduction activity. The fluoroscopic information was then analyzed using a computer aided 3D model fitting technique to determine the incidence and magnitude of hip separation. Additional variables analyzed included femoral head diameter, follow-up duration, and type of surgical approach utilized.

Less separation was noted with increasing femoral head diameter during abductionadduction.

Increased separation was observed during gait as follow-up duration increased. Hip separation was greater during gait when a posterolateral surgical approach was used but was greater in abduction-adduction if a antero-lateral approach was selected. The incidence and magnitude of hip separation during gait was least in subjects with COC THA and least with COC and MOM THA when analyzed during abduction-adduction.

It’s been proposed that THA patients are subject to femoral head separation due to alterations in the soft tissue supporting structures during THA that affect constraint of the joint.

The current analysis demonstrates lower magnitudes and incidence of THA separation occur when hard-on-hard bearing surfaces are selected and can vary based on femoral head diameter, follow-up duration, and surgical approach used. Potential detrimental effects resulting from THA separation include premature polyethylene wear, component loosening (secondary to impulse loading conditions) and hip instability.


CB Carr RD Komistek JS Cheng MR Mahfouz JW Mitchell

Low back pain (LBP) in the region of the lumbar spine is a significant problem among individuals, and efforts focused on treating both the symptoms and causes of LBP have proven to be difficult. Aside from conservative treatments, the predominant surgical approach for treating degenerative spine conditions has been to fuse the vertebral bodies at the symptomatic level. Even today, surgical fusion and its effect on adjacent levels are still not fully understood. Therefore, the objective of this study was to use fluoroscopy and mathematical modeling techniques to identify the in vivo kinematics and kinetics in subjects having either a normal, degenerative or fused condition of the lumbar spine.

Twenty-five subjects (ten normal, ten degenerative, and five fusion) were evaluated under fluoroscopic surveillance while performing flexion/extension of the lumbar spine. Subjects within the normal and degenerative groups were analyzed only once, while subjects from the fusion group were analyzed both pre-operatively and at a minimum of six months post-operative. The fusion group consisted of three subjects symptomatic at L4/L5, with the remaining two subjects symptomatic at L5/S1. In vivo kinematics data were derived using a 3D-to-2D model fitting algorithm and served as input into a 3D mathematical model of the lumbar spine. The parametric, inverse dynamics mathematical model was created to allow for the determination of the bearing surface contact and muscle forces at each level of the lumbar spine.

Three-dimensional kinematics analyses revealed that subjects classified as having a normal lumbar spine experienced a more uniform motion pattern compared to those observed in the degenerative and fusion groups. Alternatively, the degenerative and fusion subjects demonstrated a more coupled motion pattern in order to perform in plane flexion/extension. Compared to the normal group, rotations in the sagital plane decreased by an average of 28% at the pathological level in the degenerative group, while in the fusion group segmental motions slightly increased at the adjacent levels. Results from the mathematical model also revealed higher out-of-plane forces and increased loading at symptomatic and adjacent levels in both the degenerative and fused groups compared to forces observed in the normal spine.

The abnormal motion patterns, which result from decreased or loss of motion at pathological levels in the degenerative and fusion groups, are believed to result in higher resultant forces in the spine. This may be subjecting the intervertebral discs to increased stresses, and as a consequence may be linked to more rapid degeneration at levels where the abnormal kinematics are occurring.


B.N. Stulberg J.D. Zadzilka

Total hip arthroplasty (THA) and Total knee arthroplasty (TKA) are successful operations that predictably restore function and provide pain relief for up to 20 years. What happens if they fail in the elderly patient? The purpose of this review was to evaluate pain relief, function and quality of life (QOL) in octogenarian patients undergoing revision total joint arthroplasty (TJA).

We reviewed our surgical database to find all patients who were 80 years or older at the time of revision surgery. From 1993 through 2008, there were 61 revision THAs (52 patients) and 33 revision TKAs (29 patients). This represented 3% and 8% respectively of all arthroplasties and revision arthroplasties done during the same period. Outcomes evaluated include Harris Hip Scores (HHS), Knee Society Scores (KSS), complications, and QOL.

The average follow-up for revision THA patients with completed Harris Hip Evaluations was 27 months (range: 3 – 126 months). HHS improved from 47 pre-operatively to 74 at most recent follow-up. Pain Scores improved from 20 to 39, Function Scores from 11 to 16, Activities Scores from 9 to 10, Deformity Scores from 2 to 4 and ROM Scores from 5 to 6. Complications occurred in 34% of these cases. The average follow-up for revision TKA patients with completed Knee Society Evaluations was 38 months (range: 11 – 98 months). KSS improved from 48 preoperatively to 84 at the most recent follow-up. Pain Scores improved from 22 to 43 and Function Scores from 20 to 34. Complications occurred in 47% of these cases.

Total HHS and KSS greatly improved postoperatively with the most notable improvement in the Pain category. Complications were common, although most were considered minor. More severe complications occurred when revisions of all components were needed, more likely in TKA than THA. With careful selection, patient education and preoperative planning, revision TJA can be done safely and provide benefit for the elderly patient.


Hiroshi Fujita

Purpose: Cement implantation syndrome characterized by hypotension, hypoxemia, cardiac arrhythmia or arrest has been reported in the literature. Pulmonary embolization is thought to be the main reason. In our institute, however, we have not experienced major hypotension during THA. To improve longevity of THA, interface bioactive bone cement technique combined with modern cementing technique has been used in our institute. Main principle of this technique is smearing hydroxyapatite granules on the dry bony surface followed by cement pressurization. The purpose of the present study was to monitor blood pressure soon after cementing.

Method: The present study includes 91 cases of primary THA with an average age at operation of 64 years old (ranging 35 to 85). Under general anesthesia, both components were cemented using antero-lateral approach. Systolic arterial blood pressure was monitored until 5 minutes with 1 minute interval. The maximum regulation (MR%) was calculated as (maximum change blood pressure – blood pressure before cement insertion) divided by blood pressure before cement insertion.

Results: No major complications such as cardiac arrest were observed. In most of the cases, blood pressure increased until 4 minutes for the acetabular side and 2 minutes for the femoral side, and then returned to the blood pressure before cement insertion gradually. In the acetabular side, MR% was 10±13 (−19–40)%. In 52 joints (57.1%), MR% was between 10 to 40 %. In the femoral side, MR% was 5±12 (−20 to 31)%. In 32 joints (35.2%), MR% was between 10 to 31 %.

Conclusion: In the present study, major hypotension was not observed. Blood pressure increases if left ventricle reacts to the pulmonary hypertension caused by micro-embolization. If major pulmonary embolization occurs, blood pressure decrease because left ventricle can not compensate for major pulmonary hypertension caused by mayor pulmonary embolization. By good cementing technique which includes washing out debris or fat and obtaining dry bony surface just before cementing, blood pressure soon after cementing was increased.


S.D. Cook S.L. Salkeld L. P. Patron

An unconstrained, articulating pyrocarbon cervical total disc replacement (TDR; Rescue, Biomet, US) has been developed. Pyrocarbon is a chemically inert form of carbon with an elastic modulus similar to bone. The long-term durability and wear resistance of pyrocarbon has been demonstrated in other orthopaedic devices. The purpose of this study was two-fold: to compare the wear of identical disc reaplcements fabricated from cobalt chrome (CoCr) and ultrahigh-molecular-weight-polyethylene (UHMWPE) to pyrocarbon and to compare the motion at index and motion segments before and after Rescue TDR.

Ten pyrocarbon and three CoCr-UHMWPE TDRs were subjected to 10 million cycles in 20 degrees of flexion–extension with 155N axial load in serum solution at 4.0Hz. One additional CoCr-UHMWPE couple was immersed in serum and loaded to 155 N. TDRs and serum solution were examined at 0, 2.5, 5, 7.5 and 10 million cycles to characterize wear. The surfaces were measured with a coordinate measuring machine prior to and after 10 million cycles. Serum solutions and time controlled serum-only controls were characterized for the quantity of wear debris using particle analysis. Nine cadaver cervical spines were placed through dynamic 2Nm cycles of flexion, extension, and lateral bending. Electromagnetic sensors recorded the motion of each vertebral body in response to applied loads. Total range of motion at the index and adjacent levels were determined for the intact spine and after TDR.

There was no significant difference in the pyrocarbon surface geometry after 10 million cycles or in the number of particles generated during testing compared to baseline (p > 0.05).

However, CoCr-UHMWPE devices displayed classic patterns of total joint wear. CoCr-UHMWPE wear couples had an initial increase in serum particles, followed by lower particle producing rates that gradually increased. The difference in mean UHMWPE wear particles at each interval was significantly greater than with the pyrocarbon TDR (all p< 0.05).

The mean total and dynamic ranges of flexion-extension and lateral bending after implantation of the Rescue TDR at the index level were not statistically significantly different from that of the intact spine (ANOVA: p > 0.05). Similarly, at the superior and inferior adjacent levels, the mean total and dynamic range of flexion-extension and lateral bending after implantation of the Rescue device were not statistically significantly different from the intact spine (ANOVA: p > 0.05).


G.W. Stocks S.D. Self B. Thompson X.A. Adame D.P. O’Connor

Prevention of surgical infection following joint arthroplasty is preferable to treatment.

Prevention requires identification and control of the potential sources of microbial contamination. The purpose of this study was to determine whether the density of airborne particulate in the operating room during total joint arthroplasty could predict the density of viable airborne bacteria at the surgery site.

A standard particle analyzer was used to measure the number and diameters of airborne particulate during 22 joint arthroplasty surgeries performed in non-laminer flow rooms. An impact air sampler and standard culture plates were used to collect airborne particulate and were analysed to identify and count colony-forming units.

Particulate density averaged > 500,000 particles/ft3, and 1,786 colony-forming units were identified, primarily gram-positive cocci. The density of particles ≥10um explained 41% of the variation in colony-forming unit density. Colony-forming units and ≥10 um particle density increased with longer surgery duration and higher staff counts.

This is the first study to the authors knowledge that shows a correlation between the number of persons in the OR and CFUs at the surgical site during total joint arthroplasty procedures. Increasing surgical staff appear to produce both more particulate and more CFUs. These observations support the use of environmental controls that isolate and protect the surgical site from airborne particulate and microbial contamination.

Continuous monitering of particulate larger than 10 um during joint arthroplasty procedures may be warrented.


K.I. Lee K.S. Lee I.H. Kim Y.S. Oh J.H. Park S.C. Nam Y.B. Shim J.W. Jang

This study aims to identify the efficiency of biomechanical and bioactive properties of the bovine cortical bone cage treated with conditionally surface demineralization.

The procured bovine femoral bones were got rid of lipid, protein, and blood materials by chemical process such as 3% hydrogen peroxide and 70% ethanol.

The long shaft bones were cut by band saw. Several bone cages were processed by milling machine. The cortical bone cages were demineralized by 0.6N HCl treatment with various conditions, which were the tendency of HCl treatment time, position, direction. After neutralization with pH 7.0, phosphate buffered saline washing and freeze drying process, the vial vacuum packed bone cages were sterilized by 25kGy gamma irradiation. The SEM and EDS system were proceeded for morphology and Ca content in various layers of bone cage. In vitro test for cell viability and differentiation, extracted supernatant from each bone cage by tissue culture was treated in MC3T3E1 cells. For indentifying releasing materials, the others were carried for quantitative analysis by ELISA. After each conditioned period, mRNA expression was compared by RT-PCR. The axial compression and bending strength were measured by universal testing machine (UTM) for biomechanical property.

Between the outer layer and inner layer of bone cage for 2 hour’s HCl, there was concentrated Ca extracted layer. The tendency of Ca content and direction of demineralised treatment had effects on the compression and elastic strength. In vitro test, initial Osteogenic transcription factor’s mRNA expression and quantitative result of releasing material had rewarding regulation by HCl-treatment time and treated direction. Conditionally surface demineralized bone cage had good osteoconduc-tivity and osteoinductivity for spinal interbody fusion.


F. Leszko S. Zingde J.-N. Argenson M.R. Mahfouz R.D. Komistek

Previosuly, Komistek et al. have shown that the kinematics of the patellofemoral joint is altered after a TKA surgery. Specifically the implanted patella experiences significantly less rotation than the natural patella. Also, in early flexion, the patellofemoral contact positions differed significantly between implanted and non-implanted patellae. It was also found that some of TKA subjects experience patellofemoral separation. These kinematical differences may lead to adverse mechanical conditions and increase fatigue or cause loosening of the implant components. This study’s objective was to determine the three-dimensional patellofemoral kinematics and correlate it with the in vivo sound (vibrations) detected using accelerometers for subjects having a TKA and a non-implanted knee under in vivo, weight bearing conditions. The correlation of the knee mechanical conditions with the vibration data may indicate new parameters that may be used to diagnose the condition of the articular cartilage or implant components.

Fifteen subjects (average age 71.8 ±7.4years) having one implanted knee (mobile bearing Hi-Flex PS) and the healthy contralateral knee, performed

deep knee bend to maximum flexion,

chair rise and

stair climb activities under fluoroscopic surveillance.

Three miniature, piezoelectric, three-axial accelerometers were attached to the patella and femoral epicondyle. The study was approved by the Institutional Review Board and informed consent was obtained from all subjects. The sensors detected the vibration magnitudes and frequencies of the articulating patellofemoral joint surfaces. The signals were amplified and low-pass filtered at 5 kHz by a signal conditioner. The 3D tibiofemoral and patellofemoral kinematics were derived for both knees using a previously published 3D-to-2D registration technique. The 3D bone models were recovered from CT scans, while implant models were obtained from the manufacturer. The patellofemoral rotations were described using the Grood and Suntay convention. The kinematics and sound data were synchronized and recorded under fluoroscopic surveillance, for 10 patients. Then a subset of seven subjects having a TKA was re-analyzed for their contralateral (non-implanted) knee. The vibration signal was then converted to audible sound and correlated with the 3D kinematics.

On average, the subjects achieved more flexion with their TKA (103.4°±15.9°) than with their contralateral knee (96.3°±18.3°). The patellofemoral kinematics varied between the TKA and nonimplanted patella groups; the resurfaced patella experienced less flexion, less medial rotation and less tilt than the contralateral patella. The patellar flexion results were consistent with previously reported literature for both TKA and non-implanted patellae. Also, the resurfaced patellae contacted the femur more proximally than healthy patellae. Audible signals were found for both groups of subjects. The frequency analysis demonstrated that specific frequencies were in similar range for both groups, but the magnitudes and variations were different for the TKA and contralateral knees.

This study correlated 3D patellofemoral kinematics with sound under in vivo conditions for three different activities. Variable audible signals were detected for TKA and non-implanted knees. Vibration magnitude and frequency identification, under in vivo conditions, for TKA may lead to a better understanding of wear and failure modes with respect to the patellofemoral mechanics, more specifically, the patellar insert. Currently this initial study is being expanded to degenerated knee joints and failed TKAs for possible applications of the vibration analysis to the early diagnosis of knee arthritis, detection of implant loosening or wear and monitoring of implant osteointegration progress.


B.K. Nguyen J.K. Taylor A.S. Despres K. Yonemura

A critical objective of cervical total disc replacement (TDR) is to restore predictable reproducible range-of-motion (ROM) with correct kinematics, while maintaining stability of the segment. Current articulating cervical TDR devices feature fixed centers of rotation, sometimes coupled with unconstrained translation in one or more vectors. The difficulty they have in restoring reproducible, kinematically correct motion has manifest as subsequent facet degeneration as well as other problems. A Tri-Lobe articulating cervical TDR has been developed to recreate predictable, kinematically correct motion, as well as to address other common TDR problems including placement sensitivity, excess wear, instability, and imaging compatibility. The Tri-Lobe TDR design features three incongruent, self-centering, hard-on-hard articulations arranged in a tripod configuration -three hemispherical lobes oriented in a tripod configuration on the superior component articulating against mating non-congruent hemispherical pockets on the inferior component. The diameter and spacing of these articulations determines a specific -kinematic -envelope, and has been designed to match the 6-D anatomic motion data from available published sources. It has diamond-on-diamond articulations to sustain the elevated Hertzian stresses of its incongruent bearing geometry, and is engineered to couple motions in a physiologic manner. This study was designed to compare the variability and reproducibility of a Tri-Lobe cervical TDR as compared to the intact spine, and compared to a ball & trough control TDR design.

Seven human cervical spines (C2-C7) were studied (two pilot and five test specimens) utilizing a 7-Axis spinal testing system. A hybrid load/position control protocol was used to test the specimens. The intact spine was tested first in flexion/extension, lateral bending, and axial rotation to 1.5Nm. Then the C4-C5 segment was implanted with the test and control TDRs utilizing an implant placement fixture that provided accurate reproducible placement of the device in the spine. The order of test and control device placement was randomly varied. Data collected included applied moments, forces, and rotations at C2 and C7, and 3D vertebral movements via an optical tracking system (Optotrak). Statistical analysis of kinematic data was performed with paired-ANOVA followed by a Tukey-Kramer HSD post hoc test.

The ROM for flexion/extension (FE), lateral bending (LB), and axial rotation (AR) are as follows: Intact cervical motion segment FE ROM averaged 4.6±1.0 degrees (max 7.5, min 2.6, range 5.0), LB ROM averaged 1.6±0.6 degrees (max 2.5, min 1.3, range 1.2), and AR ROM averaged 9.3±0.8 degrees (max 11.7, min 6.8, range 4.8). For the Tri-Lobe TDR FE ROM averaged 4.7±0.7 degrees (max 6.5, min 2.5, range 4.0), LB ROM averaged 1.9±0.3 degrees (max 2.5, min 1.2, range 1.3), and AR ROM averaged 10.7±0.3 degrees (max 11.9, min 8.4, range 3.5). For the Ball & Trough TDR FE ROM averaged 4.9±1.6 degrees (max 9.3, min 1.5, range 7.8), LB ROM averaged 2.1±0.5 degrees (max 3.1, min 0.7, range 2.4), and AR ROM averaged 11.0±1.3 degrees (max 13.6, min 8.3, range 5.3). While there was not a statistically significant difference between the Average ROM for the intact, Tri-Lobe, or ball & trough design (p=.96), this is misleading. The variance for motion in all three categories for the ball & trough was significantly greater than for both the intact and Tri-Lobe case. Further, for the minima and maxima, the ball and trough had values that were significantly outside the intact values, while, the Tri-Lobe had values close to that of the intact. The ball & trough design exhibited 1.95, 1.84, and 1.51 times the Range of the ROM compared to the Tri-Lobe in FE, LB, and AR respectively.

Critical surgical objectives in cervical TDR include restoring predictable inematicallycorrect motion to the segment while maintaining stability. Both incorrect and excess motion can lead to instability or facet degeneration. Too little motion fails to relieve adjacent segments of the increased stresses occurring with fusion, and can lead to auto-fusion as well. With conventional articulating cervical TDR, issues such as TDR placement within the disc space as well as variations in normal anatomy can adversely affect reconstructed kinematics. The Trilobe cervical TDR studied in this experiment was able to accommodate variations in anatomy and placement providing a highly predictable and reproducible ROM matching very closely the kinematic envelope for the intact spinal motion segment. Its incongruent bearings are the key to its tolerance of variation in anatomy and placement. Its tripod design contributes to its intrinsic stability and self-centering. It may be more forgiving to surgical variability. This is not only desirable in providing the surgeon with flexibility in selecting implantation position to address deformity and bone defects, but also in providing tolerance to unpredictable variations in facet anatomy permitting acceptable motion with stability for a broad range of conditions.


C.F. Wolf P.A. Manner N.Y. Gu J.N. Doctor S.S. Leopold

Two-stage revisions for the infected THA are associated with lower re-infection rates than directexchange (one-stage) revisions, and for this reason are favored in the U.S. However, the twostage approach may result in increased, but poorly quantified, surgical morbidity. We developed a decision analysis to compare direct-exchange revision to the two-stage approach for treating the infected THA.

We performed a systematic literature search for papers that analyzed direct-and two-stage revisions for the treatment of chronic infections after THA, with a > 2 years follow-up. This provided frequencies of the most common postoperative (interim and final) health states. These were converted to monthly probabilities to permit decision analysis. We conducted and previously published two surveys to obtain utility values, one in experienced arthroplasty surgeons and another in patients. Using those probabilities and utilities, we created a Markov cohort modeling the postoperative health states seen during treatment of the infected THA.

Sensitivity analysis was performed for each variable in the tree to verify the models robustness.

Using a 12-month cycle, the Markov model favored direct-exchange revision over the twostage approach, regardless of whether surgeon-or patient-derived utilities were used (0.941 vs. 0.642 expected value (EV), and 0.889 vs. 0.551 EV, for patient-and surgeon-derived utilities, respectively; p< 0.01). These findings were also significant in a lifetime model with a ten-year life expectancy (p< 0.01). The findings were robust in sensitivity analyses using a clinically salient range of input variables.

This decision analysis, which used a systematic review of the literature (for complication and outcome frequencies) and published study-specific survey data from patients and experienced surgeons (for utility values of those health states) found direct-exchange arthroplasty to be superior to the two-stage revision for treating the infected THA. This finding was unexpected, in that this is not our typical approach nor is it favored in this country.


J.K. Taylor R.H. Dixon D. Hardy B.K. Nguyen M.G. Naylor D.W. Schroeder

Statement of Purpose: Hard-on-hard bearing surfaces are finding increasing application in total hip replacements for wear reduction. Polycrystalline Diamond Compacts (PDCs) offer several potential advantages, including ultimate hardness, reduced metal ion release compared to metal-on-metal (MoM) articulations and increased strength/ toughness compared to ceramic-on-ceramic (CoC). This study investigates in-vitro wear and friction for a 28mm diamond-on-diamond (DoD) system under normal walking gait and also with distraction.

Methods: Six sets of 28mm PDC femoral heads and 28/41mm PDC acetabular liners (Dimicron, Utah) were tested on a hip simulator (AMTI, Boston). Radial clearances were 18–42 microns. Specimens were mounted anatomically with the cups superior and mounted at 45 degrees. All stations were lubricated with 37oC bovine serum diluted to 17g/l protein concentration. Components were subjected to a 3kN walking cycle (ISO14242-1) for 5 million cycles (MC). This was followed by 2MC of distraction testing with a reduced swing-phase load of 120N, an applied side force of 129N and with the abduction motion disabled. This produced approximately 0.5–0.7mm of horizontal displacement of the center of the head. The lubricant was changed and the components cleaned, dried and weighed at 0.5MC intervals.

Results: All heads and liners gained weight during each portion of the test. Potential mechanisms (still under investigation) include protein adsorption and hydration of metallic phases within the diamond compact. The weight gains were found to be somewhat reversible after drying in vacuum for extended periods (60–90 hours). However, the standard 1 hour drying cycle used for weight measurements during the test was found to be inadequate. Therefore, only the “dry weights” measured after 64–92 hours of vacuum drying at the beginning and end of each test portion were used to compute wear rates.

Overall wear rates for heads and liners for the 5MC of normal gait and the 2MC of distraction testing and for the whole 7MC. 95% confidence intervals are plotted for each set of six heads and liners. Weight changes were converted to volumetric wear using a density of 3,800kgm-3. Even after extended drying, the liners all showed small weight gains. The heads apparently wore slightly during the normal walking cycle but gained weight during the distraction cycle. Overall, the heads showed a small wear rate of 0.17±0.09mm3/MC and the liners showed a small ‘negative’ wear rate of −0.11±0.07mm3/MC. Due to the uncertainties involved in the drying procedure, it is concluded that DoD wear rates were unmeasurably low for this test. Distraction is known to increase wear rates for CoC systems [1] and might reasonably be expected to have a similar effect for DoD, due to the high elastic modulus of diamond.

However, the 2MC of distraction testing produced only small weight gains. The heads showed no evidence of ‘stripe wear’ as reported for CoC systems.

Conclusions: DoD wear rates were found to be unmeasurably low for an anatomical hip simulator test with and without distraction. Friction factors for DoD were slightly lower than for metal-on-UHMWPE.


Qibin Ye

Objective: To study on the therapeutic mechanism of an innovated instrumentation--Plate-Rod System for scoliosis (PRSS) and its effectiveness for the surgical management of early on-set scoliosis (EOS).

Method: Between June 2000 and July 2008, 23 patients with progressive EOS who underwent one stage PRSS procedure without bony fusion.and had been followed-up for more than 2 years were evaluated prospectively. The mean age at the time of surgery was 7.98 years The experimental studies including: X-ray analysis; photo-elastic test and type ~ collagen were studied to express the therapeutic mechanism.

Results: The mean follow up period was 2.8 ±1.4 years, more than 5 years in 5 cases.

The mean scoliosis improved from 80.7° to 30.5° after surgery with a corrective rate of 62.2% and in latest follow.-up was 34.7° The length of the growth of the instrumented spine was average 13.3mm. No severe complications in our series. When PRSS is placed in place, compressive stress was found to exert on the convex side, while tensile stress on the concave side of the curvature which were reflected by the changes on the color band in the photo-elastic test and by the changes in width of the disc spaces, and more type X collagen expressed on convex side than concave side, it suggest that compressive stress leads to increase earlier cartilage degeneration of end plate in convex side correlating with the decreased growth of the end plate of this side, and resulting in maximum spinal realignment.

Conclusion: The PRSS which dispenses with spinal fusion and allows extension along with the children’s growth, is able to provide and maintain desirable correction of scoliosis in the later growing year due to its modulating efficiency in normalizing the spinal growth, This new device is an effective instrumentation for correcting scoliosis, especially for EOS.


S. Yamaguchi Y. Tanaka S. Kosugi T. Kumai Y. Shinohara Y. Takakura S.A. Banks

We have performed two-component total ankle arthroplasty (TNK ankle) since 1991 and reported good clinical results. However, in vivo kinematics of this implant are not well understood. The purpose of this study was to measure three-dimensional kinematics of total ankle arthroplasty during non-weightbearing and weightbearing activities.

Forty-seven patients with a mean age of 71 years were enrolled. Preoperative diagnosis was osteoarthritis in 36 patients and rheumatoid arthritis in 11 patients, and the mean followup was 50 months. Radiographs were taken during nonweightbearing maximal dorsiflexion and plantarflexion, and weightbearing maximal dorsiflexion and plantarflexion. Three-dimensional kinematics were determined using 3D-2D model registration techniques. Anatomic coordinate systems were embedded in the tibial and talar implant models, and they were projected onto the radiographic image. Three-dimensional positions and orientations of the implants were determined by matching the silhouette of the models with the silhouette of the image.

From non-weightbearing dorsiflexion to plantarflexion, the talar implant showed 18.1, 0.3, and 1.2 degrees of plantarflexion, inversion, and internal rotation respectively. It also translated 0.8mm posteriorly. There was not significant difference between non-weightbearing and weightbearing kinematics except for the plantarflexion angle (p = 0.007). Posterior hinging, in which tibiotalar contact was seen at only the posterior edge of the talar implant, was observed in 16 patients at either non-weightbearing or weightbearing plantarflexion. There was significantly larger plantarflexion in patients with posterior hinging than patients without hinging (p < 0.001). Nine patients showed anterior hinging at maximum dorsiflexion, and 11 patients showed talar lift-off at maximum plantarflexion.

More than half of the patients showed anterior or posterior edge contact, which might cause excessive contact stress and lead to implant failure in the longer term. This phenomenon is due to the difference in rotation axis between the natural ankle and the implant ankle arthroplasty.


W. Ren R. Zhang M. Hawkins D. Markel

We have demonstrated that erythromycin (EM) inhibits wear debris-induced macrophage activation and osteo-clastogenesis (both in vitro and in vivo) through targeting NF-κB signalling. Our clinical trial further verified that oral EM can be efficiently delivered to periprosthetic tissue and improve local inflammation. The purpose of this study was to assess the efficacy of periprosthetic EM delivery in a rat osteolysis model.

The PA coated titanium (Ti) pin (Stryker) was loaded with EM (8 μl = 2.8 mg/pin). Drug release assay showed around 25% of loaded EM was remained in the PA layer 24 hours after loading. Rats were divided into three groups:

saline control (n=5);

UHMWPE particle injection (n=7), and

UHMWPE particle injection with EM treatment (n=7).

Uncoated Ti pins were pressfit inserted into right tibia following the injection 200 μl of either UHMWPE particles (5 mg/ml) or saline (control). The revision surgeries were performed 6 weeks after the first surgery. The previous implanted pins were replaced with new Ti pins either with or without EM coating. Rats were then sacrificed one month after “revision surgery”, and the knee joint samples were collected for μCT and histology analysis.

μCT analysis showed that the value of bone volume (bv/tv) in the group treated with EM (0.26 ± 0.07) was significantly higher than the group untreated (0.14 ± 0.04), while there was no significant difference between EM treated group and the saline control group (0.15 ± 0.11). The parameters of cancellous bone structure all pointed a trend of better structure in EM treated group than other two groups. However, this difference did not reach statistical significance. Histology analysis (H& E staining) demonstrated that in the saline control the tibia retained a smooth endocortical surface with a prominent periprosthetic membrane. In the EM-treated group, endocortical erosion was reduced and the peri-prosthetic tissue appeared thinner than uncoated pins.

The overall cellularity of periprosthetic membranes from the EM-treated group was decreased compared to the untreated group. Analysis of membrane thickness revealed a significantly thinner membrane in EM-treated group compared with untreated group and saline control (p< 0.05).

The results of this study seem to indicate that an EM coated Ti pin provided a sufficient drug source to effectively treat wear debris-induced periprosthetic inflammation and osteolysis.


K. Uchiyama N. Takahira S. Takasaki K. Fukushima T. Yamamoto K. Urabe M. Itoman

Several stems have been used for revision of total hip replacement (THR). Moreover, management of proximal femoral bone loss at the time of revision THR remains one of the challenges for hip surgeons. Recently, impaction bone grafting has been suggested to resolve this problem, but it is a demanding technique that results in frequent complications.

We have used the Wagner self-locking stem with cancellous chip allograft for reconstruction of proximal femoral bone defect during revision surgery since 1992.

This study evaluated the midterm results of using Wagner revision stem with bone allograft for femoral revision of THR. We could evaluate forty-one femoral revisions performed between 1992 and 2005 using Wagner revision stem with bone allograft.

All patients had been followed for a minimum of three years with a mean follow-up of 8.6 years. Preoperative radiological femoral bone defects were assessed and classified by Gustillo’s classification. Subsidence of the stem was measured on radiograms taken immediately after revision surgery and again at the latest follow-up. Femoral component fixation was graded as radiographic ingrowth, fibrous stable, or unstable according to the criteria described by Engh et al. The incidence of surgical complications was examined. Allografts were assessed for incorporation into host bone as evidenced by trabecular bridging of the host-graft interface. A clear reduction in density or breakdown of the allograft was defined as bone resorption. Kaplan-Meier survival analysis was performed. The end point was revision because of mechanical loosening of the stem.

Bone defects were classified as: 10 hips type I, 20 hips type II, and 7 hips type III and 4 hips were a periprosthetic fracture. Subsidence was measured at the time of last follow-up in six hips (3, 3, 12, 16, 21, 30 mm). At the latest follow-up 37 of 41 stems were stable. Allograft incorporation could clearly be observed in the proximal femoral bone defects of 31 stems. Three stems were defined as showing bone resorption. Surgical complications included 11 intraoperative fractures, two femoral shafts were perforated during reaming, one dislocation postoperatively, and 3 greater trochanter pseudoarthroses. There was one deep infection, and these cases were excluded from survivorship analysis. One unstable stem and one stem with infection had to be revised. Kaplan-Meier survival was 97.1 % at 10 years.

Wagner self-locking stem with allograft for reconstruction for proximal femoral bone defect in revision surgery is a beneficial procedure. However, because there is a high incidence of intraoperative fractures, surgery should be performed carefully.


T.R. Yoon K.S. Park K. Thevarajan Y.J. Cho H.K. Yang

The aim of the present study was to report the midterm follow up results of second generation metal-on-metal cementless total hip arthroplasties in patients younger than 50 years.

From December 1997 and January 2003, 91 metal-on-metal cementless primary total arthroplasties in 77 patients (who were younger than 50 years) were performed in our institution. Among them 72 hips in 63 patients could be followed more than 5 years. There were 18 women (22 hips) and 44 men (50 hips) with a mean age at surgery of 39 years (range 22 to 49 years) and a mean follow up of 7 years (range 5 to 10 years).

The most common cause of total hip replacement were avascular necrosis of femoral head (37 hips in 28 patients, 51%) and second one was osteoarthritis (13 hips in 13 patients, 18%). We used Fitmore (Zimmer, Winterthur, Switzerland) cup in all cases and used 28mm Metasul femoral head. About the femoral stem, CLS (Protek AG/Zimmer, Bern, Switzerland) stems were used in 48 hips and Cone prosthesis® (Protek AG, Berne, Switzerland) were used in 24 hips.

We evaluated clinical result using Harris hip score (HSS) and the Western Ontario and McMaster Universities Osteoarthritis index (WOMAC) score and radiological evaluation was done using the method of DeLee and Charnley for the acetabular osteolysis and method of Gruen et al. for the femoral osteolysis.

The mean HSS improved from 58.9 (range 35 to 69) preoperatively to 92.2 (range 82 to 100) postoperatively. The mean WOMAC score improved from 72.2 (range 63 to 94) preoperatively to 29.2 (range 17 to 51) postoperatively. In radiological evaluation, all femoral and acetabular component were well fixed without loosening or subsidence. But osteolysis was observed in 10 (14%) of total 72 hips (Acetabular osteolysis in 5 cases-Zone 2; 2, Zone 3; 3, Femoral osteolysis in 6 cases-Zone 1; 6, Zone 7; 1).

About the major complications, there were immediate postoperative deep infection 1 case, delayed infection 1 case and recurrent dislocation 1 case. There was no revision case due to aseptic loosening.

The treatment of second generation metal-on-metal cementless total hip arthroplasties in patients younger than 50 years showed favorable midterm results.


B.D. Haas J.K.P. Mueller J.E. Dowd R.D. Komistek M.R. Anderle M.R. Mahfouz

Subjects having a posterior cruciate ligament sacrificing (PCLS) mobile bearing TKA seem to experience less translation during gait, but often achieve less weight-bearing flexion. More recently, posterior stabilisation has been added to PCLS mobile bearing TKA, hoping to increase flexion. Therefore, the objective of this multi-center study was to determine the in vivo kinematics for subjects implanted with a mobile bearing PS TKA that attempts to maintain high contact area.

Subjects with 10 TKA from 2 surgeons were asked to perform maximum weight-bearing flexion (deep knee bend (DKB)) and gait while under fluoroscopic surveillance. During weight bearing flexion, the 3-D kinematics of the TKA were determined by analyzing fluoroscopic images in the sagittal plane at 30 degree increments. Fluoroscopic images taken in the frontal plane from four increments during the stance phase of gait were analyzed.

The average weight-bearing flexion was 116 degrees and the average medial and lateral anteriorposterior (AP) translation was posterior with −1.9 mm and −5.4 mm, respectively, from full extension to maximum weight-bearing flexion.

The average femorotibial axial rotation from full extension to maximum weight-bearing flexion was 3.9 degrees. During the stance phase of treadmill gait, patients experienced 0.8 mm (0.1 mm to 2.3 mm, SD=0.8 mm) of “pure” mediolateral translation of the femur relative to the tibia. The femorotibial axial rotation was 4.6 degrees from heel-strike to toe-off (Table 3).

The posterior femoral rollback and axial rotation patterns were similar to the normal knee, albeit experiencing less overall motion. More noticeably, subjects in this study experienced a significantly greater weight-bearing flexion than previous subjects analyzed with a mobile bearing PCLS TKA and more reproducible “fan-like” patterns, where the lateral condyle rolled greater posteriorly than the medial condyle.


L Sedel J Delambre R Nizard D Hannouche

Introduction: While an increasing number of authors have reported on the long-term results of primary alumina total hip arthroplasty (THA) [1], strategies for revising a ceramic-on-ceramic THA are debated in the literature. According to some authors [2], the reimplantation of a ceramic head on a well-fixed femoral stem is inadvisable, as it may lead to a fracture of the newly implanted head. The aim of the present study was to evaluate the incidence of this specific issue, and to report on the clinical and radiological results of the revised hips.

Methods: Between January 1977 and December 2005, 138 consecutive alumina-alumina revision hip arthroplasties were performed in 127 patients. There were 79 women (62.2%) and 48 men (37.8%), with an average age of 67 years (range, 32–91 years). Among these, an isolated acetabular revision was performed in 108 cases. The reason for revision was aseptic loosening of the acetabular component in 98 hips, pain in 7, fracture of an alumina liner in 2, and recurrent dislocation in 1. The revised socket was a cemented alumina in 56 hips, a threaded screw-in titanium with an alumina core in 34, a pressfit titanium with an alumina core in 11, and bulk alumina in 7. Acetabular bone stock losses were classified according to the AAOS system. Most of the hips had a contained type II defect (86%). In all cases, the femoral stem was left in place and the acetabular component alone was revised. At the time of revision surgery, an aluminaalumina combination was implanted in 27 hips, an aluminapolyethylene combination in 56, a metal-poly-ethylene combination in 15, and a zirconia-polyethylene in 10. Overall, a ceramic head was reimplanted on a used femoral taper in 59 cases. Acetabular reconstruction with allografts supported with the Kerboull acetabular reinforcement device was performed in 31% of the hips.

Results: The mean follow-up period was 78 ± 37 months. Thirteen patients (15 hips) died a mean 37 months after surgery. Sixteen patients were lost to follow-up. Postoperatively, five hips had a recurrent dislocation, 2 a deep infection, 9 a trochanteric nonunion (21,3%), 6 a transient nerve palsy. 18 hips required a re-revision surgery, 12 of which for aseptic loosening of the acetabular component. Among the 59 ceramic heads implanted on a well-fixed stem, no fracture of the head occurred at a mean 81 months follow-up. Of the original 108 hips, 77 were available for clinical evaluation and 75 for radiological evaluation at least 2 years after surgery. The mean Merle d’Aubigné score increased from 10.1 ± 2.1 to 16.7 ± 1.1 at the latest follow-up (p< 0.001). Forty-five hips were graded excellent or very good (60%), 26 good (34,6%), 3 fair (4%), and 1 poor (1.3%). When revision for aseptic loosening was considered as a failure, the overall survival rate at 8 years was 96.3 ± 1.8%.

Discussion & Conclusions: In the present study, aseptic loosening of the acetabular component was the main reason for revision surgery. Osteolysis around ceramic implants was moderate and was related to the migration of the socket. Among the ceramic heads implanted on a used titanium trunnion, no fracture was observed. This approach is possible, in so far as careful inspection does not show any major imperfection of the morse taper [3]. As for other bearing surfaces, the management of aseptic loosening of al-al prostheses is based on the amount of osteolysis around the loosened socket.


H. Oonishi S.C. Kim H. Oonishi M. Kyomoto M. Iwamoto M. Ueno

In total hip arthroplasty (THA), one of concerned issues is osteolysis due to wear debris of ultra-high molecular weight polyethylene (PE) which often leads to aseptic loosening. Reduction of PE wear debris is essential to prevent osteolysis, and different bearing combination as well as improvement of the bearing material itself have been attempted. Hence alumina ceramics was introduced for THA, aiming to reduce PE wear debris. Ceramic on PE couple showed good results in clinical wear compared with metal on PE couples. Highly cross-linked PE (HXLPE) with gamma-ray or electron-beam irradiation followed by thermal treatment has also demonstrated a remarkably low wear in the previous in vitro studies. In in vivo studies, the wear of HXLPE acetabular cups against alumina ceramic femoral head was evaluated to compare with that of conventional PE cups against alumina ceramic femoral head.

The in vivo wear of 61 HXLPE cups (Aeonian; Kyocera Corp., Kyoto, Japan, currently Japan Medical Materials Corp., Osaka, Japan) against alumina ceramic femoral head of 28 mm in diameter with clinical use for 2.1–7.1 years (mean 5.6 years) and eight conventional PE cups against an alumina ceramic femoral head of 28 mm in diameter used for 18.7–23.3 years (mean 20.4 years) were examined by radiographic analysis with Vector Works 10.5. The in vivo wear of eight retrieved HXLPE cups with clinical use for 0.9–6.7 years (mean 2.9 years) and 14 retrieved conventional PE cups used for 16.0–28.0 years (mean 22.0 years) were examined by using a three-dimensional coordinate measuring machine. The worn surfaces of retrieved HXLPE and conventional PE cups were observed by a scanning electron microscope.

In the radiographic study, penetration rate of alumina head into HXLPE and conventional PE for the first 1 year were 0.24 mm/year and 0.34 mm/year respectively. One year later, the HXLPE showed significant lower penetration rate of 0.001 mm/year than the conventional PE penetration rate of 0.12 mm/year (p< 0.01). By the retrieval analysis, the mean penetration of retrieved HXLPE and conventional PE cups were 0.11 and 2.97 mm, and they were similar to the results by radiographic analysis. In the worn surface of the retrieved HXLPE cups used for around 1 year, machine marks were observed. In contrast, the worn surface of the retrieved HXLPE cups used for more than five years were smooth, and furthermore, in high magnification observation they had wear morphology different from conventional PE. These findings from this retrieval study suggest the penetration in the first 1 year detected by radiographic measurement was probably caused by creep deformation in bedding-in stage; and 1 year after, the penetration was probably caused mainly by wear.

By the radiographic analysis, HXLPE cups against alumina ceramic femoral head has a 99 % lower wear rate compared with conventional PE cups. Also, retrieved HXLPE cups against alumina ceramic femoral head exhibited lower wear compared with conventional PE cups. In conclusion, we expect that the HXLPE cup used with alumina ceramic femoral head has favorable wear properties in long-term clinical use.


L.H. Walschot R. Aquarius B.W. Schreurs N. Verdonschot P. Buma

Bone impaction grafting (BIG) is a surgical technique for the restoration of bone stock loss with impaction of autograft or allograft bone particles (BoP). The goal of a series in-vitro and in-vivo experiments was to assess the suitability of deformable pure Ti (titanium) particles (TiP, FONDEL MEDICAL BV, Rotterdam, The Netherlands) for application as a full bone graft substitute in cemented revision total hip arthroplasty. TiP are highly porous (interconnective porosity before impaction 85 to 90%). In-vitro acetabular reconstructions were made in Sawbones (SAWBONES EUROPE, Malmö, Sweden) to evaluate migration by roentgen stereo photogrammetric analysis and shear force resistance by a lever out experiment. In-vitro femoral TiP reconstructions (SAWBONES, Malmö, Sweden) were used to evaluate micro-particle release and subsidence. Mature Dutch milk goats were used for two in-vivo experiments.

A non-loaded femoral defect model was used to compare osteoconduction of bioceramic coated TiP with BoP and ceramic particles (CeP).

Acetabular defects (AAOS type 3) were reconstructed in 10 goats using a metal mesh with impacted TiP acting as a full bone graft substitute in combination with a cemented polyethylene cup and a downsized cemented Exeter femoral stem (STRYKER BENOIST, Girard, France).

Blood samples were taken for toxicological analysis.

In-vitro: TiP were as deformable as BoP and created an entangled graft layer (porosity after impaction 70 to 75%). Acetabular TiP reconstructions were more stable and resistant to subsidence and shear force than BoP reconstructions (lever-out moment 56 ± 12 Nm respectively 12 ± 4 Nm, p < 0.001). After initial setting, femoral subsidence rates were smaller than seen in femoral bone impaction grafting (0.45 ± 0.04 mm after 300 000 loading cycles). Impaction generated 1.3 mg particles/g TiP (particle Ø 0.7–2 000 μm, tri-modal size distribution). In-vivo: Bioceramic coated (10 −40 μm) TiP showed bone ingrowth rates comparable to BoP and CeP. Reconstructed acetabular defects showed rapid bone ingrowth into the layer of TiP. Serum titanium concentrations slowly increased from 0.60 ± 0.28 parts per billion (ppb) preoperatively to 1.06 ± 0.70 ppb at fifteen weeks postoperatively (p = 0.04).

Mechanical studies showed very good initial mechanical properties of TiP reconstructed defects. The in-vitro study showed micro-particle generation, but in the short-term goat studies, histology showed very few particles and no negative biological effects were found. The in-vivo acetabular study showed very favorable bone ingrowth characteristics into the TiP layer and a much thinner interface with the cement layer compared to similar defects reconstructed with BoP or mixtures of BoP with CeP. Further analysis in a human pilot study should proof that TiP is an attractive and safe alternative for allograft bone in impaction grafting revision arthroplasty.


M.T. Cadag R.B. Gustilo L.A.C. Leagogo

Several hundred Joint Replacement Surgeries have been done by surgeons (Gustilo/Leagogo) of the Philippine Orthopedic Institute in the Philippines since its inception over 20 years ago. Revision surgery of failed cemented hip replacement, have been increasing in the last decade, which is the subject of this report. The average total cost of revision hip surgery in the Philippines ranges from PEP 800 000 to PEP 1 000 000 or USD 20 000 to USD 25 000.

All medical records of the patients were reviewed to determine the following:

Etiology

Duration from index surgery

Common anatomical pathology and amount of leg length discrepancy encountered.

Revision implants used and use of allograft.

Postoperative course and complications

Preliminary results (How many are ambulatory with or without assistive device).

Analysis of x-ray at last follow-up.

A total of sixty nine (69) patients were included in the study. Sixty eight percent (68%) of the patients (47 out of 69) underwent revision due to aseptic loosening of components (femoral or acetabular). Nine (9) patients (13%) developed infection. Six (6) patients (9%) developed protrusio acetabuli that necessitated revision. Peri-prosthetic fracture was noted in four (4) patients (6%). Three (3) patients had hip dislocation (4%) prior to revision. Average number of years from index surgery is 9 years (2–18years).

Fifty nine (59) patients (86%) underwent cemented total hip prior to revision while ten (10) patients (14%) underwent cemented partial hip replacement prior to revision. Fifty six (56) patients (81%) have shortening on the affected side with an average of 3cm (1–6cm). Forty five (45) patients (65%) had proximal femoral bone loss requiring structural allograft. Thirty one (31) patients (45%) had acetabular defect (Paprosky Types I & II).

In sixty five (65) patients (94%), Active LockTM Cementless Hip Revision System was used. All patients were allowed full weight-bearing after revision surgery. Four patients (6%) developed acute post-op infection. Two patients (3%) had dislocation after revision surgery. At short-term follow-up of one year or more, only 5 patients were ambulating with assistive device. The rest are ambulatory, without aid and are symptom free.

Follow-up radiographs showed implants in excellent alignment, no signs of loosening, migration or subsidence.

The main reason for revision hip arthroplasty in the Philippines is aseptic loosening (68%) followed by infection (13 %). The use of long non-cemented, calcar-replacing curved revision stem, and strut allograft on the femoral side; jumbo, cementless acetabular socket and a high hip center on the acetabular side, addressed the problem of anatomic pathologies as a result of failed, cemented THR. There is no association between cause for revision with gender and age of the patients.


T.J. Blumenfeld W.L. Bargar

Introduction: Failure to restore offset in severe protrusio defects in revision total hip replacement can lead to impingement and loss of limb length. The purpose of this study was to determine the initial results obtained with a novel cup in cup technique utilizing two porous tantalum acetabular shells, one placed onto supportive host bone in a cementless fashion, the other cemented in to this shell.

Methods: Porous tantalum hemispherical shells were implanted in 4 revision total hip replacements in 3 patients with an average age of 73 years at the time of the procedure.

Bony defects per the Paprosky classification were one IIC, two IIIA, and one IIIB. All patients were followed clinically and radiographically.

Results: The patients were followed for an average of 25.5 months (range, 17 to 29 months). Abductor strength improved by one grade in all patients. In the non-bilateral reconstruction patients horizontal offset was increased compared to the normal hip by 6 mm (IIIB) and 8 mm (IIC). For the bilateral reconstruction patient (IIIA) horizontal offset compared to pre-op was increased by 13–16 mm. There was no evidence of loosening or migration at the time of final follow-up.

Conclusions: At short term follow-up the early experience cautiously supports the use of this construct. Long term follow-up and a larger patient experience will be required to evaluate the results of this novel technique.


K Kawashima T Tomita T Yamazaki K Futai N Shimizu M Tamaki M Kurita Y Kunugiza T Watanabe T Shigeyoshi H Yoshikawa K Sugamoto

Recently mobile-bearing total knee arthroplasty (TKA) has become more popular. However, the advantages of mobile bearing (MB) PS TKA still remain unclear especially from a kinematic point of view. The objective of this study was to investigate the difference and advantage in kinematics of mobile baring PS TKA compared with fixed bearing (FB) PS TKA.

Femorotibial nearest positions for 19 subjects (20 knees), 10 knees implanted with NexGen Legacy flex (Zimmer, Warsaw, IN)with mobile bearing PS TKA, and 10 knees implanted with NexGen Legacy flex (Zimmer, Warsaw, IN)with fixed bearing PS TKA were analyzed using the sagittal plane fluoroscopic images. All the knees were implanted by a single surgeon. All the subjects performed weight bearing deep knee bending motion. We evaluated range of motion, axial rotation of the femoral component, AP translation of medial and lateral sides.

The average range of motion between femoral component and tibial component was 119°±18° in MB and 122°±10 ° in FB. The axial rotation of the femoral component was 11.8°±6.2° in MB and 11.8°±4.9° in FB. There was no significant difference both in range of motion and axial rotation between MB and FB. The AP translation of MB and FB showed same patterns. They were rollback in early flexion, the lateral pivot pattern (the medial condyle moved forward significantly compared with the lesser amount of AP translation for the lateral condyle) at mid flexion, and bicondylar rollback at deep flexion. The rollback in early flexion was 3.4mm in MB and 1.8mm in FB at medial side, 4.2mm in MB and 4.8mm in FB at lateral side. There was no significant difference. The lateral pivot pattern, which moved anteriorly, was 7.8mm in MB and 7.0mm in FB at medial side, 3.0mm in MB and 2.4mm in FB at lateral side. There was no significant difference. The bicondylar rollback at deep flexion was 6.4mm in MB and 7.7mm in FB at medial side, 6.9mm in MB and 4.8mm in FB at lateral side. In four subjects, more than 12°axial rotation was observed in knees implanted with FB TKA which allows only 12°axial rotation.

The results in this study demonstrate that there was no significant difference in kinematics of weight bearing deep knee bending motion between MB and FB. The advantage of MB is allowance of axial rotation which restricted until 12° in FB NexGen Legacy flex PS TKA.


T. Morishima S. Hirose H. Otsuka D. Hattori S. Sawada K. Sato

We used the D-dimer level as a measure for the early diagnosis of deep vein thrombosis (DVT), which can cause fatal pulmonary thromboembolism (PTE), following total hip arthroplasty (THA). Recently, we have performed anticoagulation therapy, in addition to the use of elastic stocking and intermittent pneumatic compression, for the prevention of DVT. In the present study, we examined the effect of administration of anticoagulation drugs on the changes in the D-dimer level.

Of 123 patients who had undergone THA between April 2003 and October 2007, 70 patients who were available for 3 or more measurements of the D-dimer level were included in this study. These 70 patients were divided into the following three groups: N group consisting of 30 patients who were not given anticoagulation drugs (4 males, 26 females; mean age 69 years (45–87 years); mean body mass index (BMI) 24.1 (15.8–28.5)), W group consisting of 23 patients who were administered dose-adjusted warfarin at a dose of 5 mg within 3 days after surgery and at 1–3 mg following 1-day rest (3 males, 20 females; mean age 62 years (48–83 years); mean BMI 24.1 (17.8–35.9)), and F group composed of 15 patients who were given fondaparinux (2.5 mg) between postoperative days 1 and 14 (6 males, 11 females; mean age 64 years (51–81 years); mean BMI 23.1 (18.2–31.6)). There was no significant difference in sex ratio and BMI between the three groups, while a significant difference in age was found between the N and F groups. The D-dimer level was measured on days 3, 7, 10, 14 and 21 and changes in the median D-dimer level were compared between groups.

In the N group, the D-dimer level was around 8 μg/ml between postoperative days 3 and 10 and exceeded 10 μg/ml on postoperative day 14. In the W group, the D-dimer level was around 8 μg/ml between postoperative days 3 and 14 and decreased thereafter.

In the F group, the D-dimer level was less than 3 μg/ ml on postoperative day 3, increased gradually thereafter until postoperative day 14, reaching the maximum level of approximately 8 μg/ml, and then decreased thereafter.

The D-dimer level was significantly different between the N and F groups and between the W and F groups on day 3, between the N and F groups and between the W and F groups on day 7, and between the N and W groups on day 21. With regard to hemorrhagic adverse events, neither major nor minor bleeding event was observed in either the W or F group.

The present study suggested that fondaparinux is effective for preventing DVT in an early postoperative period, with relatively low D-dimer levels observed between postoperative days 3 and 10.

We expect that various types of anticoagulation drugs will be used in the future.

Elucidating the effect of these drugs on the D-dimer level will help in the early diagnosis of DVT.


M.R. Anderle S.M. Zingde R.D. Komistek D. A. Dennis M.R. Mahfouz

All over the world, obesity rates are on the rise. Medical complications and increased health risks are often associated with being overweight or obese, but a thorough understanding of in vivo motions for obese, overweight and normal weight subjects does not exist. Therefore, the objective of this study was to compare knee kinematics in TKA subjects by body mass index (BMI).

In vivo knee kinematics were determined for 253 TKA subjects during a Deep Knee Bend (DKB) from full extension to maximum flexion using a 3D to 2D image registration technique. Each of these subjects was then classified into one of three BMI categories: obese (BMI greater than or equal to 30), overweight (BMI greater than or equal to 25 and less than 30) and normal weight (BMI less than 25 and greater than or equal to 18.5). Subjects were provided by 11 surgeons using ten different TKA devices. All subjects were deemed clinically successful.

On average, weight bearing range of motion (ROM) for the obese (n=79), overweight (n=113) and normal weight (n=61) groups were 107.7° (range: 74° to 136°, standard deviation (σ) =14.9°), 109.6° (60° to 150°, σ=17.5°) and 114.1° (72° to 147°, σ=14.4), respectively. ROM of 90° or less was seen in 16.5% of the obese subjects, 14.2% of the overweigh subjects and 6.6% of the normal weight subjects. ROM of 125° or more was seen in 15.2% of the obese subjects, 16.8% of the overweight subjects and 23.0% of the normal weight subjects.

From full extension to maximum flexion the obese, overweight and normal weight groups averaged 8.65° (−5.14° to 22.51°, σ=6.22°), 7.58° (−2.85° to 24.72°, σ=5.71°) and 5.72° (−4.84° to 19.43°, σ=5.65°) of axial rotation. Axial rotation of 3° or less was seen in 20.25% of the obese subjects, 23.01% of the overweight subjects and 39.34% of the normal weight subjects. Axial rotation of greater than 9° was seen in 51.90% of the obese subjects, 35.40% of the overweight subjects and 26.23% of the normal weight subjects. Opposite axial rotation was seen in 8.86% of the subjects in the obese group, 9.73% of the overweight group and 9.84% of the normal weight group.

On average, from full extension to maximum flexion, the medial condyle for the obese, overweight and normal weight groups experienced −5.44mm (−22.20mm to 8.04mm, σ=7.9mm), −6.30mm (−25.22mm to 5.35mm, σ=7.36mm) and −4.78mm (−20.79mm to 5.49mm, σ=6.68mm) of posterior femoral rollback (PFR), respectively. The obese, overweight and normal weight groups averaged −12.66 mm (−34.57mm to 0.34mm, σ=9.32mm), −12.38mm (−36.72mm to 1.83mm, σ=10.33mm) and −9.39 mm (−34.55mm to 0.35mm, σ=8.98mm) of lateral PFR, respectively.

Condylar lift-off of greater than 1mm was seen in 16.46% of obese subjects, 10.62% of overweight subjects and 11.48% of normal weight subjects.

Various statistical differences were seen across the groups. The normal weight subjects had significantly higher ROM that the obese subjects (p=0.0184), while there was no difference seen between the normal weight and overweight groups or the overweight and obese groups. The obese and the overweight groups had significantly more axial rotation than the normal weight group from 0° to 90°, 0° to maximum flexion, 30° to 90°, 30° to maximum flexion and 60° to 90°. There were a significantly higher number of cases of condylar lift-off for obese subjects when compared to both normal weight and overweight groups.

It can be concluded that body mass index does play a factor in TKA kinematics.


K. Sasaki S. Kubo T. Matsumoto K. Ishida K. Tei T. Matsushita M. Kurosaka R. Kuroda

Purpose: Continuous femoral nerve block (CFNB) has been revealed to be a safe and effective method to decrease postoperative pain after total knee arthroplasty (TKA).

However, optimal duration for CFNB to decrease pain and accelerate rehabilitation program after TKA has not been addressed. We, therefore, compared three groups of patients which had different duration of CFNB (0, 2, and 5days) in this study.

Methods: Sixty patients who received primary TKA for osteoarthritis were divided into three groups based on the duration to receive CFNB for 0day, 2days or 5days (twenty patients for each group). Ropivacaine 2mg/mL was given through the femoral nerve catheter using elastomeric infusers (delivering 2ml/hr for each group).

Outcomes including visual analog scale (VAS) pain scores and range of motion (ROM) were compared at 1st, 3rd, 6th, 14th and 21th days after surgery. In addition, the postoperative date when patients could walk stably with parallel bar, walker, or T-cane were recorded and compared.

Results: At 1st and 3rd day postoperatively, the VAS was significantly better in the CFNB 2 days and CFNB 5 days group than in the CFNB 0 day group (P< 0.05).

ROM did not show significant difference among the three groups over postoperative days 1st to 21st (P> 0.05), although groups with the CFNB showed greater ROM at all time points. The CFNB 5 days group obtained stable walking ability with T-cane earlier than other groups (P< 0.05). No patient had any side effect by having CFNB in this study.

Discussion: Postoperative use of CFNB reduced pain at first 3days, and shorten the time to acquire stable walking ability after TKA. We conclude that CFNB should be kept for 5days after surgery to decrease pain and accelerate rehabilitation program after TKA.


I. Nakahara N. Nakamura H. Miki M. Takao T. Sakai T. Nishii H. Yoshikawa N.

Using a larger diameter femoral head in total hip arthroplasty (THA) has advantages in terms of the increased joint stability and range of motion. And the wear resistance of highly cross-linked polyethylene (HXLPE) even combined with a larger head has already been demonstrated by in vitro studies. The purpose of this study was to compare the in vivo wear of Longevity HXLPE sockets against 32 mm and 26 mm heads at a 5-year follow-up.

From November 2000 to November 2001, 51 primary cementless THAs were performed with a 26 mm cobalt-chromium head and a Longevity HXLPE socket (Zimmer). A cohort of 32 mm cobalt-chromium heads was comprised of 51 THAs with the same prosthesis performed from December 2001 to December 2003. No significant differences between the groups were observed in gender, age, and BMI, however, polyethylene liners with 32 mm heads were significantly thinner than those with 26 mm heads. Two-dimensional linear wear was measured using PolyWare software on annual x-rays, and total head penetration rates at postoperative 5-year and steady state wear rates were calculated. In addition, periprosthetic osteolysis was evaluated.

At the 5-year follow-up, the total head penetration rates were 0.047±0.022 mm/year with 26 mm heads and 0.048±0.026 mm/year with 32 mm heads. The steady state wear rates were −0.008 mm/year with 26 mm heads and 0.001 mm/year with 32 mm heads. No significant differences were seen between the two groups (p=0.82 and p=0.24). Osteolysis was not observed around pros-theses in any hips.

At the 5-year follow-up, the wear rate of Longevity HXLPE was very low. A Longevity HXLPE socket will undergo the same level of wear whether with a 32 mm head or a 26 mm head.


H. Haider J.N. Weisenburger K.L. Garvin

Sub-micron polyethylene particles produced by the wear of metal on ultra-high molecular weight polyethylene (UHMWPE) in artificial joints have been identified as a principle culprit in the osteolysis frequently found in the bone surrounding these implants. To eliminate UHMWPE debris, highly crosslinked (HXL) UHMWPE and hardon-hard bearing surfaces have been developed. This study compares the wear rates of 14 designs and/or material combinations (total of 48 specimens) tested on a hip simulator in the biomechanics lab at the University of Nebraska Medical Center.

Twelve ceramic-on-metal (COM) (six 36mm and six 28mm, of high and low clearance (HC, LC)), twelve metalon-metal (MOM) (44mm, 3 TiN coated, 3 uncoated standard, and 6 resurfacing components), eighteen metal-on-UHMWPE (MOP) (36mm: six with CoCr-coated heads and six uncoated standard heads with conventional UHMWPE; 44mm: 3 conventional UHMWPE and 3 HXL), and six ceramic-on-UHMWPE (COP) (three 44mm and three 32mm all with conventional UHMWPE) were tested on a multi-station hip simulator (AMTI, Boston). The specimens were lubricated with bovine serum diluted to 20g/l protein concentration at 37°C and were subjected to the loading and rotations of the walking cycle as specified in ISO-14242-1 at 1Hz (for 5 million cycles (Mc) except where specified otherwise). The liners (and heads where specified) were cleaned and weighed at 0, 0.25, 0.5, and every 0.5Mc afterwards.

For 36mm COM liners the wear rates of HC and LC were the lowest observed (−0.019±0.118mg/Mc and −0.061±0.044mg/Mc, respectively). All three 28mm COM HC and one LC liner exhibited “break-away” wear in that they would lose several milligrams (HC: 5.99mg, 6.37mg, 8.50mg, LC: 10.22mg) after showing nearly no measurable wear (HC: 0.905±0.467mg/Mc, 28mm LC: 0.422±0.982mg/Mc). (Note that COM heads weighs were not quoted here but none of them lost weight). TiN-coated MOM THRs (heads and liners) showed higher wear than the uncoated MOM THRs (8.53±4.07mg/Mc, 3.19±0.281mg/Mc, respectively) as the TiN wore away from all three coated heads and liners. The MOM resurfacing components showed wear rates of 2.77±1.27mg/Mc over 2Mc. The 36mm MOP liners (CoCr-coated and uncoated heads) showed wear rates of 55.6±4.26mg/Mc and 44.5±4.46mg/Mc, respectively, as the coating wore away from the metal heads. Wear rates of the 44mm MOP conventional and HXL liners were 72.0±2.81mg/Mc and 14.2±3.57mg/Mc respectively. For COP, the larger size wore at a higher rate than the smaller size (44mm: 97.4±3.08mg/Mc, 32mm: 51.3±12.2mg/Mc) over 2Mc. The 44mm COP THR displayed the highest observed wear rate.

Our simulator results confirm low wear for hard-on-hard bearing couples (MOM, COM) except where coating failure had occurred. Size-36mm LC COM bearings faired the best of the four COM types tested (showing no measurable wear and no “break-away” wear). MOP THRs showed better wear performance when HXL UHMWPE was used, and also showed a sensitivity to femoral head coating removal. COP THRs showed high wear in the large 44mm size, and less in the smaller size. Simulator wear testing was able to successfully discriminate and characterize wear rates of different material bearing couples and different sizes/designs.


J.N. Weisenburger M.G. Naylor D.W. Schroeder B.F. White A. Unsworth K.L. Garvin H. Haider

With the boom in metal-on-metal hip resurfacing and hard-on-hard total hip replacements (THRs) with extremely low wear, accurate tribological measurements become difficult. Characterizing THR friction can help in this, especially if the progress of such friction can be tracked during wear tests. Friction measurement can also be used as a tool to study the effects of acetabular-liner deformation during insertion, and possible femoral head “clamping”. This study presents estimates of friction during extended wear testing on THRs of the same size but with different material combinations, using a technique (previously introduced) based on equilibrium of forces and moments measured in the simulator.

All tests were based on five million cycles (Mc) and samples of size-44mm (head diameter). Samples included 6 metal-on-UHMWPE (MOP) (3 with conventional UHMWPE and 3 with highly-cross-linked (HXL) UHWMPE liners), 6 metal-on-metal (MOM) (3 TiN-coated and 3 uncoated), 6 MOM resurfacing (3 standard and 3 with small pockets for lubrication transport), and 3 ceramic-on-UHMWPE (COP) THRs (MOM resurfacing and COPs for 2Mc only). All were lubricated with diluted bovine serum with 20g/l protein concentration at 37°C, and subjected to the loading and rotations of the walking cycle in ISO-14242-1 on a twelve-station hip simulator (AMTI, Boston).

The conventional and HXL MOPs had steady friction factors of 0.045±0.009 and 0.046±0.003 over 5Mc, explained by the stability of wear rates of both these MOP types (72.0±2.81mg/Mc and 14.2±3.57mg/Mc, respectively). However, during the “bedding-in” period (first 0.5Mc), the conventional MOP friction factor rose from 0.047±0.004 to 0.057±0.004 while high wear was occurring (147.1±10.08mg/Mc). The TiN-coated and uncoated MOMs displayed initial friction factors of 0.124±0.117 and 0.039±0.003 respectively. The high standard deviation for the coated THRs was due to coating removal on one specimen which caused scratches and scuffs on its articulating surfaces. This specimen had a friction factor of 0.260 at 0.028Mc. By 1Mc, the TiN coating wore away on the other two coated specimens (friction factors at 1Mc: coated 0.081±0.036, uncoated 0.050±0.014). Over the 5Mc test, average friction factors for the coated and uncoated THRs were 0.097±0.020 and 0.049±0.014 respectively. The 44mm standard and “pocketed” MOM resurfacing THRs displayed initial friction factors of 0.038±0.009 and 0.059±0.026 respectively that increased to the same level at 2Mc (0.094±0.020 and 0.094±0.029, respectively). No difference in wear was detected between the two resurfacing head types (wear rates over 2Mc: standard 3.32±0.25mg/ Mc, pocketed 2.22±1.76mg/Mc), but curiously, both types exhibited an equal level of scratching and scuffing on their articular surface. Finally, the three COP THRs exhibited high liner wear over 2Mc (97.44±3.08mg/Mc), which slowed after the “bedding-in” period. The friction factor also decreased from 0.091±0.005 to 0.070±0.008 over the same period as the UHMWPE liner conformed to the ceramic head.

The method utilized here facilitates on-line sampling throughout the progress of a prolonged wear test, and therefore allows predictions on THR performance/wear to be made. When high friction factors were observed, a high wear rate was occurring and measured on the THR specimens, or damage to articulating surfaces was seen.


C. Ketonis A. Ayier I. Shapiro J. Parvizi N. Hickok

Use of allograft bone has become standard for bridging defects unlikely to heal by simple fixation and routinely used in revision arthroplasties for implant stabilization. Unfortunately, this decellularized allograft provides an ideal surface for bacterial colonization, necessitating repeated surgeries, extensive debridement and lengthy antibiotic treatments. With up to 18% infection rate following allograft surgeries, a need for more effective means to prevent this process is evident. We describe a novel modification of native bone allografts that renders their surface bactericidal while increasing the effectiveness of systemic antibiotic treatments.

Allograft modification: Morselized human bone was washed extensively and sequentially coupled: 2X with Fmoc-aminoethoxyethoxyacetate (Fmoc-AEEA); deprotected with 20% piperidine in Dimethylformamide (DMF); and then coupled with vancomycin (VAN) for 12–16 hours. The VAN-bone was washed extensively with DMF and PBS for at least 1 day. VAN immuno-fluorescence: Control or VAN-bone was washed 5X with PBS, blocked with 10% FBS (1hr), incubated with rabbit anti-VAN IgG (4oC, 12h) followed by an Alexa-Fluor 488-coupled goat anti-rabbit IgG (1hr), and visualized by confocal laser microscopy. Antibiotic Activity. Equal dry weights of control and VANbone were sterilized with 70% ethanol, rinsed with PBS, and incubated with either Staphylococcus aureus (S. aureus) or Escherichia Coli (Ci=104 cfu) in TSB, 37oC, for 2, 5, 8 and 12 hrs. Antibiotic treatment: Clinical grade vancomycin was added to the solution with bacteria or following infection at a final concentration of 10μg/ml. Bacterial counts: Non-adherent bacteria were removed by washing and adherent bacteria suspended by sonication in 0.3% Tween-80 for 10mins followed by plating on 3M® Petrifilms. Bacterial visualization: Non-adherent bacteria were removed by washing extensively with PBS and adherent bacteria stained with the Live/Dead BacLight Kit (20mins, RT) to cause viable bacteria to fluoresce green. Samples were visualized by confocal microscopy.

In comparison to controls, VAN-bone consistently reduced the graft bacterial load by ~90% at all time points. After staining and visualization of adherent bacteria, biofilm formation was apparent on controls by 12 hrs and absent from VAN-bone. E.coli, a gramnegative organism that is not sensitive to VAN, readily colonized both control and VANbone, confirming retention of VAN specificity. We then evaluated VAN-bone activity in a system that modeled systemic antibiotic therapy and antibiotic prophylaxis. In the absence of solution antibiotics, VAN-bone exhibited a significant decrease in bacterial colonization as compared to controls. When 10 μg/ml VAN was added to the medium for the last 4 h (modeling systemic antibiotic therapy), colonization of control surfaces was reduced, while colonization of VAN-allograft was almost eliminated. When 10 μg/ml VAN was added concomitantly with S. aureus, VAN-bone colonization was undetectable, while colonization of control surfaces still occurred.

We have previously described an antibiotic-tethered allograft that resists bacterial colonization. In this abstract, we test this technology with an vitro model of bone implantation in the presence of solution antibiotics. In these models, solution antibiotics failed to prevent infection of control bone while completely clearing the bacteria on VAN-bone. Furthermore, VAN bone exhibited high activity against S. aureus, a gram positive organism, whereas it was ineffective against E. coli, a gram negative organism. The specificity of the tethered antibiotic supported the view that the antibacterial properties of the allograft were related to the tethered antibiotic and not to undefined aspects of the attachment chemistry. In terms of antibacterial activity, when challenged with 104 CFU S. aureus (with concentrations reaching > 107 CFU by 24 h), the antibiotic -modified allograft consistently decreased bacterial colonization by > 90%; S. aureus inocula < 102 CFU resulted in no detectable colonization of the VAN-allograft. Thus, development of these allografts may not only combat allograft colonization but increase the effectiveness of prophylactic antibiotics to ultimately result in a new therapy for allograft-associated infection.


L. Puri T.C. Moen D. Villacis

When compared with traditional techniques, computer-assisted total knee arthroplasty (TKA) has been shown to allow more accurate coronal alignment of the implants with fewer “outliers.” Most navigation systems in computer-assisted TKA utilize rigidly-fixed trackers placed on both the femur and tibia, a computer workstation, and navigation software to determine the mechanical axis of the extremity intraoperatively, in real time. The purpose of this study was to report the initial experience of a single surgeon with a novel navigation system. This system utilizes a “pinless” technique using trackers that are mounted at the articular surface of the knee instead of being fixed to the femur and tibia.

Sixty-Six consecutive TKAs were performed using a novel “pinless” navigation system by a single surgeon. At 4 weeks post-operatively, coronal alignment was assessed with long-standing AP radiographs. The alignment measurements were then compared to historical controls.

The average alignment in the coronal plane was 1.73° +/−1.50° deviation from neutral alignment. Variance was 2.26°. The c onfidence interval constructed with an alpha value of.05 was (1.50°, 2.40°). Five knees had a coronal alignment greater than 3° from neutral. Of these five, three had an ipsilateral total hip replacement, and 2 were morbidly obese. There were no pin site infections nor pin site fractures. There was 1 late hematogenous infection.

This study reports an initial single-surgeon experience of a novel “pinless” navigation technique for TKA. The technique in this study is a novel and safe method to reconstruct a neutral mechanical axis, as it avoids the morbidity of the application of navigation tracking pins and therefore enhances patient safety.


G.L. Rasmussen

Placement of total knee arthroplasty components is typically controlled via resections that reference bony landmarks. For example, external rotation of the femoral component can be pre-determined by referencing the posterior condyles or the epicondylar axis. Such approaches exclude consideration of any potential effect of the collateral ligaments before resection are made. In addition, bone referencing instrumentation usually limits femoral component placement to discrete values of external rotation such as 3° or 5°. The purpose of the present study was to determine external rotation of the femoral component following use of a novel ligament balancing approach and to assess the accuracy of balancing the flexion and extension gaps with this ligament balancing system.

One hundred twenty knees in 110 patients were consecutively enrolled by a single surgeon using the same implant across subjects. All patients underwent arthroplasty that set external rotation of the femoral component based upon use of a novel ligament balancing system. Following ligament tensioning/balancing, the femur was prepared.

Thicknesses of the medial and lateral posterior condylar resections were measured and the difference between the two measurements was calculated. When placed into relation with the line formed by the distance between the midpoints of the distal condyles (reference line), the difference in the condylar resections gives the height of a right triangle. The arc tangent function was then used to calculate the resultant angle (external rotation) formed from the reference line and the hypotenuse. The average, range and standard deviation of the external rotation values was found.

External rotation averaged 6.9° (+/−2.8°) and ranged from 0.6° to 12.8°. Fifty-four percent of femoral components were sized 3, 4 or 5. The external rotation values in this study were 4° and 2° larger, respectively, than the typical 3° and 5° discrete values that are common to measured resection systems.

External rotation values are higher on average, when ligament tensioning/balancing is employed with this novel system compared to measured resection systems. Also, the standard deviation and range suggests that true femoral rotation varies greatly between patients. This finding suggests that limiting the surgeon to discrete rotation values may be at odds with where the femur “desires” to be, given soft tissue considerations for each patient. Future work includes determining whether there is a functional difference between measured resection and this ligament tensioning/balancing approach.

The accuracy of the ligament balancing system was assessed by applying equal tension on the ligaments using a tensioning bolt and torque wrench in flexion and extension after the bone resections had been made. The resulting flexion and extension gaps were then measured to determine rectangular shape and equality of the gaps.

Rectangular flexion and extension gaps were obtained within 0.5 mm in all cases.

Equality of the flexion and extension gaps was also obtained within 0.5 mm 100% of the time. To the best of our knowledge, this system and technique has produced better accuracy balancing the flexion and extension gaps in total knee arthroplasty than has previous been reported.


Y.J. Cho K.I. Kim Y.S. Chun K.H. Rhyu J.H. Song M.C. Yoo

We wanted to evaluate the clinical and radiological results of acetabular revision using the acetabular reinforcement ring and allograft impaction in patients with severe acetabular bony defect.

41 hips revision arthroplasty using reinforcement ring were performed between April 1997 and October 2005 and were followed up for more than two years. The cause of primary arthroplasty was AVN in 18 cases, secondary osteoarthritis (OA) in 17 cases, fracture in cases and primary OA in 1 case. The cause of revision arthroplasty was acetabular cup loosening in 20 cases, massive osteolysis in 14 cases, infection in 4 cases, liner dissociation in 2 cases, and recurrent dislocation in 1 case. The average period between primary and revision arthroplasty was 11.4 years (range 0.6 to 29.1 years). Acetabular defects were classified based on the AAOS classification and Paprosky classification system. All were treated with autografts or allografts. Muller ring was used in 18 cases, Burch-Schneider ring was used in 14 cases, and Ganz ring in 9 cases. Clinical evaluations were performed according to the Harris hip score (HHS), and the radiographic results were evaluated by progression of acetabular component loosening, union of bone grafts, periacetabular osteolysis, and migration of the hip center.

The mean preoperative Harris hip score of 64.9 was improved to 91.8 points at the latest follow-up. There were 39 cases of type 3 defect, 2 cases of type 4 defect according to the AAOS classification and 8 cases of type 2B defect, 3 cases of type 2C defect, 28 cases of type 3A defect, and 2 cases of type 3B defect according to Paprosky classification.

Radiographically, the bone grafts were well united except one case. The mean preoperative hip center of rotation which was vertically 32.3mm, horizontally 33.2 mm migrated to vertically 26 mm, horizontally 33.2 mm postoperatively and it was statistically significant.

The mean preoperative abductor lever arm of 41.7 mm changed to 45 mm postoperatively which was statistically insignificant. However the mean preoperatiave body lever arm of 89.4 mm changed to 96.9 mm postoperatively which was statistically significant. Postoperative complications were cup loosening in 1 case, dislocation in 2 cases, and recurrence of deep infection in 1 case.

Clinically and radiographically, acetabular reconstruction using reinforcement ring showed very promising short term result. We conclude that reinforcement ring can provide stable support for grafted bone in severe bone defect. But meticulous surgical technique to get initial firm stability of ring and optimal indication in mandactory for the successful result.


M.R. Mahfouz M.J Kuhn

Wireless technologies applied to the medical field have grown both in prevalence and importance in the past decade. Various applications and technologies exist underneath the telemedicine umbrella including Point-of-Care systems where electrocardiographs, blood pressure, temperature, and medical image data are recorded and transmitted wirelessly, which enables remote patient monitoring from inside hospitals, personal residences, and virtually any location with access to satellite communication. Another widespread application for wireless systems in hospitals is asset tracking, typically done with RFID technology. Wireless technologies have not been widely used in computer assisted orthopaedic surgery (CAOS) because of the limitations in terms of overall 3-D accuracy.

We have developed a wireless positioning system based on ultra wideband technology (UWB) which achieves mm-range 3-D dynamic accuracy and can be used for intraoperative tracking in CAOS systems. Current intraoperative tracking technologies include optical and electromagnetic tracking systems. The main limitations with these systems include the need for line-of-sight in optical systems and the limited view volume and susceptibility to metallic interference in electromagnetic tracking systems. UWB indoor positioning does not suffer from these effects. Until this point, the main limitation of UWB indoor positioning systems was its limitation in 3-D real-time dynamic accuracy (10–15 cm as opposed to the required 1–2 mm).

We have developed a UWB indoor positioning system which achieves dynamic 3-D accuracy in the range of 5–6 mm for a non-coherent approach and 0.5–1 mm for a coherent approach (transmitter and receiver use the same clock signal). The integration of this tracking system with smart surgical tools opens up a plethora of exciting intraoperative applications including picking landmarks, 3-D bone and instrument registration, real-time wireless pressure sensing used for ligament balancing in TKA, and real-time A-mode ultrasound bone morphing. The UWB tracking system will be presented along with its integration into smart surgical tools and surgical navigation.


M Roche S Horowitz M A Conditt

Clinical outcomes of UKA procedures are sensitive to malalignment of the components, and thus show significant variability in the literature. This study evaluates the two year clinical results of a new surgical procedure designed to significantly increase the accuracy and precision of the alignment of the components, and thus increase postoperative functional outcomes.

A new UKA technique has been developed, which combines tactile guided robotic technology with image guided surgery. Three-dimensional planning of the implant positioning is followed by precise resection of the bony surfaces. To date, 73 (42 male, 31 female) patients (average age: 70±10yrs) are 2 years postoperative with all patients enrolled in an IRB approved outcomes registry. The tibial component was an allpoly inlay design.

At two year followup, all patients showed significant improvements, compared to pre-operative values, in Knee Society Knee (p< 0.0001) and Function (p< 0.0001) scores, sf-12 PCS scores (p< 0.0001), WOMAC total scores (p< 0.0001) and WOMAC pain (p< 0.0001), stiffness (p< 0.0001) and physical function (p< 0.0001) subscores. The tibial components of two patients have been revised to a standard metal backed onlay UKA for loosening.

This initial series of robotically guided UKA implantations provided significant improvement in the postoperative function of patients in every functional measurement with only two revisions to date, likely for improper patient selection. These patients were revised to standard UKA components. The introduction of new procedures and technologies in medicine is routinely fraught with issues associated with learning curves and unanticipated pitfalls. Because the explicit objectives of this novel technology are to optimize surgical procedures to provide more safe and more reliable outcomes, these favorable results provide the potential for significant improvements in orthopedic surgery.


K. Fujiwara N. Abe H. Endo K. Nishida S. Mitani T. Ozaki M. Suzuki T. Saito N. Sugita Y. Nakajima M. Mitsuishi T. Inoue K. Kuramoto Y. Nakashima

ROBODOC is a well known tool for a computer assisted arthroplasty. However, the incision tends to enlarge with the system because of the restriction of range of motion. We have developed the robot system for minimally invasive arthroplasty. This report shows the accuracy of our system composed of original planning software, navigation and bone cutting robot.

We took the DICOM data of cadaver knees from computed tomography. The data were transferred to the workstation for planning. Matching points for registration and cutting planes were determined on the planning software. Cutting tool was the 6th robot which was able to recognize the locations of its apex and the cadaver knee with navigation system. We made five planes for TKA and two planes for UKA on femur. Then we made one plane on tibia. We evaluated the accuracy by measurement the location of cutting plane under navigation system and by CT data.

The registration errors of femur and tibia were less than 1.0mm about cadaver knees. The errors of cutting planes were 1.3 mm about the distal end of femur and 0.5 mm about the proximal end of tibia. The accuracies of the angles of cutting planes were 1.9 degrees and 0.8 degrees compared to the mechanical axis.

The errors of anterior and posterior plane of femur were increased compared to the distal plane. It was because the accuracy of registration were correct in axial direction but was not satisfied in rotational direction. The error was considered by the location of points which decided the rotation alignment. We will make effort to minimize the errors of registration and put it into practical use as soon as possible.


Rimon Tadross Mohamed Mahfouz

Computer assisted knee arthroplasty systems provide the surgeon with tools for planning the femoral and tibial cuts, automatic implant sizing, and precise guidance for the bone milling and sawing tools. These systems require 3D models of the patient’s proximal tibial epiphysis, and distal femoral epiphysis. Currently preoperative CT scans are used to construct these models. The high irradiation, financial and time cost of the CT motivated the research for an alternative. In this work we developed a system for reconstructing a 3D bone model from a set of points localized by the surgeon intra-operatively on the bone surface using an optical localizer.

A training set of 314 dry femurs, and 314 dry tibias (200 males, and 114 females) of Caucasian ethnicity was CT scanned, and segmented to create 3D models for these bones. These models were then used to extract the modes of variation for the femurs and tibias within each gender. Using these modes of variation along with the average model for the training set, a new femoral or tibial epiphysis model can be reconstructed. This reconstruction is performed by optimizing the average model’s morphology along the modes of variation to create a 3D model that matches the point cloud localized on the surface of the bone.

A set of 77 male and 71 female dry femur and tibia pairs was used to digitize a sparse point cloud on the knee joint using an optical localizer. These point clouds were then used to reconstruct their corresponding models using the aforementioned algorithm. An average error of 0.42 between the reconstructed and the CT models was obtained.


J.T. Daniel A. Kamali H. Ziaee D.W.J. McMinn

Evidence with respect to conventional hip arthroplasties suggests that device wear is related to patient activity rather than duration of usage. Activity level questionnaires appear to suggest that subjects with resurfacing arthroplasties continue to remain active after the procedure. However there is a paucity of objective evidence relating to the step rates of these patients in their daily lives and its effect on metal ions generated. The aim of this investigation is to assess

the activity levels of hip resurfacing patients as follow up progresses and

if there is any correlation between activity and metal ions generated.

Twenty-five consecutive male patients (average age 56 years) who underwent a unilateral 50 mm diameter hip resurfacing carried out by a single surgeon (DJWM) were recruited after informed consent. Patient step activity (Step Activity Monitor, SAM, Cymatech. Seattle WA, USA) was recorded at 1, 2, and 4-year follow-up stages and at the same time patient whole blood samples were collected and analysed using High Resolution Inductively Coupled Mass Spectroscopy (HR-ICPMS).

All patients in this study had well functioning hips at the four year follow up stage. All femoral components implanted were within the desired range of neutral to 10°. The mean acetabular component inclination angle was 42° (33° – 55°). Patient overall step activity remains unchanged up to the 4-year follow-up period.

At one year follow up, the whole blood cobalt and chromium concentrations show no correlation to mean number of steps taken per day by each patient (r2=0.02).

The correlation between whole blood cobalt and chromium concentration versus a function of body weight and peak index is not significant (r2=0.11).

This study provides objective evidence of the activity rates of patients at different stages of follow-up after a MoM surface replacement arthroplasty. It should be emphasised that the walking speeds of these patients on average was significantly slower than 1 Hz, which is generally used in laboratory hip simulator studies.


R.M. Jacobberger F. Namavar K.L. Garvin H. Haider

In recent years, patterned ultra-hydrophilic thin films have received attention because of their potential as bio-compatible surfaces for implants. However, mechanical properties of the studied surfaces are not sufficiently robust for the majority of applications. Via an ion-beam assisted deposition process, we have fabricated nanostructurally stabilized, pure cubic zirconia thin films possessing properties of hardness (16 GPa) and wettability, which are expected to benefit tribology and wear reduction. These transparent, zirconia coatings are maximally wettable by water and bovine calf serum, which is explained by the Wenzel model based on the nanotextured surface and surface energy.

The effect of aging on hydrophilic properties of cubic zirconia was determined by water contact angle (CA) measurements on samples stored in a laboratory environment from February of 2005 until now. Measurements for samples without any cleaning showed CA of around 90°, indicating surface adsorption of moisture, organic contaminants, and/or gases over time. A cleaning procedure consisting of sonication in organic solvents followed by calcination at temperatures ranging from 300°C to 600°C was found to effectively burn off residual organic contaminants, yielding CA about 10° to 20°. X-ray diffractometry and atomic force microscopy analysis of these samples revealed that the cleaning procedure induced no apparent changes in the crystal structure and nanotextured surface.

We conclude that the observed loss of ultra-hydrophilic properties was due to organic contaminants. Our results reveal a cleaning method for the long-term maintenance of the wettability of zirconia, making it a viable material for applications involving hard, hydrophilic surfaces, such as biomedical implants.


J David Blaha David DeBoer C. Lowry Barnes Richard Obert Satya Nambu Paul Stemniski Michael Carroll

Introduction: Many attempts have been made to describe the flexion axis of the knee based on landmarks or simple geometric representations of the anatomy. An alternative approach is to use kinematic data to describe the axis of motion of the joint. The helical axis is one kinematic parameter that can accomplish this. The purpose of this study was to compare the correlation between kinematic and anatomic axes of motion.

Methods: Six cadaver lower extremities were skeletonized except for the knee joint. Passive navigation markers were implanted, and CT scans obtained. The limbs were then placed in an open-chain lower extremity rig that allows full range of knee motion. Threedimensional kinematic data were recorded using a camera and the helical axis of motion was calculated. Anatomic landmarks were placed on CT derived CAD models of the extremities consisting of spherical and cylindrical fits of the femoral condyles and a trans-epicondylar axis. Data for the normal knee was processed, by comparison of the helical axis to the landmark axes over varying ranges of flexion and the variation in helical axis direction within that range was also calculated.

Results: The flexion range with the minimum variation of anatomic parameters to the helical axis was 30–100°. Helical axis variation in this range was 5.489 ± 1.173, while variation between the helical axis and those axis defined by spherical, TEA, and cylindrical landmarks were 5.115 ± 2.129°, 3.127 ± 2.029°, and 5.111 ± 1.710°, respectively. A students t-test was performed on each data set with the null hypothesis that the angular difference between the anatomically defined axes and the helical axis is zero. All axes were found to be significantly different from the average helical axis in the range of 30–100° (P= 0.002, 0.013, and 0.001, respectively). The tightest variation in the helical axis occurred at 40–50° of flexion 2.89 ± 0.722.

Conclusion/Discussion/Summary: None of the anatomic landmarks considered in this study represent a consistently valid approximation of the kinematic flexion axis of the knee. The TEA represents the closest approximation of the three with a 95% CI between 0.998 and 5.256°. The range of 30–100° represented the tightest variation over the largest range of flexion. Extension was defined at approximately 30° based on kinematic profiles of internal/external rotation which show a “screw-home” tendency beginning at 30° through extension. This behavior is consistent with an increase in helical axis variation in ranges that were less than 30° of flexion. In a previous open-chain model, both compartments of the joint were spinning around 45 degrees of flexion, which is consistent with the smallest helical axis variation observed in the 40–50° range.


F. Leszko K.R. Hovinga M.R. Mahfouz A.L. Lerner M.R. Anderle R.D. Komistek

Previous in vivo studies have not documented if ethnicity or gender influence knee kinematics for the healthy knee joint. Other measurements, such as hip-knee-ankle alignment have been previously shown to be significantly different between females and males, as well as Japanese and Caucasian populations in the young healthy knee [1]. Differences in knee kinematics in high flexion positions may relate to both etiology of osteoarthritis and success in knee replacement designs. Although differences in knee anatomy have been identified, their significance in knee function has not yet been clarified. Therefore, the objective of this study was to determine the 3D, in vivo normal knee kinematics for various subjects from different gender and ethnic backgrounds, and to identify significant differences, if any, between populations.

The 3D, in vivo, weight bearing normal knee kinematics was determined for 79 healthy subjects, including 48 Caucasians, 24 Japanese, 42 males, and 37 females. Each participant performed deep knee bend activity from a standing (full extension) to squatting to a lunge motion, until maximum knee flexion was reached. The study was approved by the Institutional Review Board and informed consent form was obtained from all subjects. The 3D bone models, created by segmentation from MR images, were used to recreate the 3D knee kinematics using the previously described fluoroscopic and 3D-to-2D registration techniques (Fig. 1) [2,3]. Tibiofemoral rotations were described using the ISB recommended Grood and Suntay convention [4,5]. Anterior-posterior translations of the centers of the posterior femoral condyles were normalized due to significantly different anthropometry in the subjects. Anterior cruciate ligament (ACL) laxity was also measured using a KT-1000 device for 72 of these subjects. Statistical analysis was performed using the Student’s t-test, set at the 95% confidence interval.

Most subjects achieved very high flexion, however substantial variability occurred in all groups. Range of motion (ROM) varied from 117° to 177°, while average external rotation was 31°± 9.9° for all subjects. Japanese and female subjects achieved greater ROM than Caucasian (p=0.048) and male (p=0.014) subjects. From full extension to 140° of flexion (which 87% of subjects achieved), few significant differences between any of the populations were observed. At deeper flexion, the external rotation was higher for female than for male subjects, however not statistically significant (p=0.0564 at 155°). Also at deep flexion, the adduction was significantly higher for female subjects. The translations of the lateral condyle were very similar between respective groups, but at deep flexion, the medial condyle remained significantly more anterior for females, leading to greater axial rotation and ROM. As ACL laxity increased, flexion/extension ROM significantly increased (r2=0.184, p< 0.001). In addition, ACL laxity was also higher for females (6.8 mm) compared to males (5.6 mm, p=0.011), as well as Japanese (7.5 mm) compared to Caucasian (5.6 mm, p=0.0002) subjects.

High variability and ROM in knee kinematics were similar to those seen in previous studies of healthy subjects during a deep knee bending activity [6]. Subjects in this study achieved much greater axial rotation and ROM than previously analyzed TKA patients. A relationship was found between greater axial rotation and increased ROM, and may be related in part to increased ACL laxity in the knee. Significant differences in ROM and laxity were identified between genders and ethnic groups. Also the medial condyle remaining significantly more anterior for females than for males in deep flexion may explain higher external rotation and consequently higher flexion experienced by women. However, understanding the causes for variability within each group may be the key to improved implant design.


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Robert E. Booth

Surgical skills and the principles of efficient behavior are often formed very early in a clinical career. They are rarely consciously analyzed or critically evaluated thereafter. Indeed, it is fair to say that more surgeons have videotaped their golf swing than their surgical technique.

Operative efficiency is a critical ingredient to surgical success. Efficiency creates speed and speed begets volume. Complication rates are directly related to shortened surgical times and highly efficient operative procedures. The concept of creating “muscle memory” through repetitive task, of eliminating costly gaps in surgical flow, and the willingness to analyze and alter even the most successful practices are the essence of personal improvement. While patterns of behavior in surgical experience vary enormously, the principles of expeditious surgeries include such mundane considerations as consistent staff, a simplified surgical system, extensive preoperative preparation, instruments that suit the surgeon more than the patient, and the innate desire to improve the result with every procedure. While rarely discussed, the concepts of appropriate volumes, outcomes oversight, and cost accountability will undoubtedly define the success of joint centers in the 21st t century.


G.R. Scuderi

Surgical instrumentation for total knee arthroplasty has improved the accuracy, reproducibility and reliability of the procedure. In recent years, minimally invasive surgery introduced instrumentation that was reduced in size to fit within the smaller operative field; with this move the impact and influence of technology became proportionately larger. The introduction of computer navigation is an attempt to improve the surgeon’s visibility in a limited operative field, improve the position of the resection guides, and ultimately the position of the final components.

While it may be appealing to rely on computer navigation to perform a TKA, it is not artificial intelligence and does not make any of the surgical decisions. The procedure still is surgeon directed with navigation serving as a tool of confirmation with the potential for improvements in surgical accuracy and reproducibility. The accuracy of TKA has always been dependent upon the surgeon’s judgment, experience, ability to integrate images, utilize pre-operative radiographs, knowledge of anatomic landmarks, knowledge of knee kinematics, and hand eye co-ordination. Recent advances in medical imaging, computer vision and patient specific instrumentation have provided enabling technologies, which in a synergistic manner optimize the accurate performance of the surgery. The successful use of this technology requires that it not replace the surgeon, but support the surgeon with enhanced intra-operative feedback, integration of pre-operative and intra-operative information, and visual dexterity during the procedure. In developing smart tools or robotic systems, the technology must be: safe; accurate; compatible with the operative field in size and shape, as well be able to be sterilized; and must show measurable benefits such as reduced operative time, reduced surgical trauma and improved clinical outcomes. Advocates believe this is attainable and robotic assisted TKA can achieve levels of accuracy, precision and safety not accomplished by computer assisted surgery.

Smart instruments and robotic surgery are helping us take the next step into the operating room of the future. The role of robots in the operating room has the potential to increase as technology improves and appropriate applications are defined. Joint replacement arthroplasty may benefit the most due to the need for high precision in placing instruments, aligning the limb and implanting components. In addition, this technology will reduce the number of instruments needed for the procedure potentially further improving efficiency in the operating room. As technology advances, robots may be commonplace in the surgical theater and potentially transform the way total knee arthroplasty is done in the future. Robotic surgery and smart tools are new innovative technologies and it will remain to be seen if history will look on its development as a profound improvement in surgical technique or a bump on the road to something more important.


Y-H Kim J-S Kim

It has been suggested that the wear of ultra-high molecular weight polyethylene (UHMWPE) in total hip replacement is substantially reduced when the femoral head is ceramic rather than metal. However, studies of alumina and zirconia ceramic femoral heads on the penetration of an UHMWPE liner in vivo have given conflicting results.

The purpose of this study was to examine the surface characteristics of 30 alumina and 24 zirconia ceramic femoral heads and to identify any phase transformation in the zirconia heads. We also studied the penetration rate of alumina and zirconia heads into contemporary UHMWPE liners. The alumina heads had been implanted for a mean of 11.3 years (8.1 to 16.2) and zirconia heads for a mean of 9.8 years (7.5 to 15).

The mean surface roughness values of the explanted alumina heads (Ra 40.12 nm and Rpm 578.34 nm) were similar to those for the explanted zirconia heads (Ra 36.21 nm and Rpm 607.34 nm). The mean value of the monoclinic phase of two control zirconia heads was 1% (0.8% to 1.5%) and 1.2% (0.9% to 1.3%), respectively. The mean value of the monoclinic phase of 24 explanted zirconia heads was 7.3% (1% to 26%).

In the alumina group, the mean linear penetration rate of the UMWPE liner was 0.10 mm/yr (0.09 to 0.12) in hips with low Ra and Rpm values (13.22 nm and 85.91 nm, respectively). The mean linear penetration rate of the UHMWPE liner was 0.13 mm/yr (0.07 to 0.23) in hips with high Ra and Rpm values (198.72 nm and 1329 nm, respectively). This difference was significant (p = 0.041).

In the zirconia head group, the mean linear penetration rate of the UHMWPE liner was 0.09 mm/yr (0.07 to 0.14) in hips with low Ra and Rpm values (12.78 nm and 92.99 nm, respectively). The mean linear penetration rate of the UHMWPE liner was 0.12 mm/yr (0.08 to 0.22) in hips with high Ra and Rpm values (199.21 nm and 1381 nm, respectively). This difference was significant (p = 0.039).

The explanted zirconia heads which had a minimal phase transformation had similar surface roughness and a similar penetration rate of UHMWPE liner as the explanted alumina head.


Douglas A. Dennis Richard D. Komistek Raymond H. Kim Adrija Sharma

An institution of the authors (Center for Musculoskeletal Research) and one author (DAD) have received funding from DePuy, Inc. (Warsaw, IN).

Each author certifies that his or her institution has approved the reporting of these cases, that all investigations were conducted in conformity with ethical principles of research, and that informed consent for participation in the study was obtained.

This work was performed at Center for Musculoskeletal Research, University of Tennessee, Knoxville, TN and the Rocky Mountain Musculoskeletal Research Laboratory, Denver, CO.


M.R Mahfouz

Technological advances and economic trends are shaping the future of orthopaedics, where a clinical solution encompasses all phases of surgery. Minimally invasive surgery (MIS) continues to become more popular and important in modern-day orthopaedics, but brings added complexity to the operating room. Computer assisted surgery (CAS) has the potential to provide greater reliability, repeatability, and control to orthopedic surgeries, although limitations in the technologies currently available for minimally invasive CAS procedures leave much to be desired. Despite new techniques and modern technologies, improvements are needed to achieve consistency of optimal patient outcomes in orthopaedic surgery. Healthcare markets are moving to emphasize the value of patient-specific intervention with reliable, custom solutions.

We are developing a framework for orthopedic CAS which utilizes new technologies and a cohesive approach in providing a robust solution for the future of orthopaedics. Through the use of surgical preplanning, intra-operative guidance, and post-operative gait analysis, a full analysis and design cycle is used to ensure optimal patient outcome by focusing on the combination of the three surgical phases. In order to realize this comprehensive framework, a system-level design approach combined with cutting-edge technology is needed, catering to patient-specific anatomical reconstruction.

In the pre-operative phase, X-ray images are used in the 3-D reconstruction of patient-specific models of the targeted anatomy. This is combined with automated morphometric measurements to provide automatic cutting plane alignment and a complete design suite for patient-specific implants. In the intraoperative phase, new wireless navigation technologies provide robust performance where optical and electromagnetic tracking systems fall short. MEMS capacitive sensor array technology provides accurate and real-time pressure sensing feedback for ligament balancing, and new software frameworks virtualize surgical protocols. Extensive gait analysis including X-ray fluoroscopy provides 3-D kinematic data in the post-operative phase to provide valuable feedback on implant performance for improved implant design.


R. Schwarzkopf F.J Kummer W.L Jaffee

The analysis of hip joint vibrations (phonoarthrography, vibration arthrometry, vibroarthrography, hip auscultation) has been explored as a means to assess joint pathologies, disease status and recently, incipient prosthesis failure. Frequencies < 100Hz have been used to diagnose gross pathology and wear in knee prostheses, frequencies from 1k to 10k Hz for progression of osteoarthritis, and frequencies > 10k Hz for loosening of cemented hip prostheses. It is possible that detailed analysis of higher frequencies could detect and quantify the smaller geometric changes (asperities) that develop in articular prosthetic wear.

We examined the ultrasound emission generated by various types of hip prostheses and native hips of 98 patients. The ultrasonic transducer was attached to the skin over the greater trochanter with a hypoallergenic, transparent dressing using a standard acoustic coupling gel layer on the microphone face to improve skin contact. The transducer was attached by a 2m cord to a battery operated, data recorder/logger. The patients were asked to sit in a chair, rise, sit again and then rise and take 5 steps while recording the acoustic data from these two movements of sitting and walking. This procedure was repeated for the opposite hip in each patient as well. Acoustic emission analysis examined frequency distributions and power spectrums of the recorded signals and their relations to prosthesis type and implantation time. Review of x-rays of prosthetic and native hips was carried out with OA grading and prosthetic wear quantification.

We have obtained data on 79 metal-polyethylene (average duration of 8.5 years; 0.1–28), 20 ceramic-ceramic (average duration of 8.5 years; 0.5–10), 17 metal-metal (average duration of 1.2 years; 0.1–5.5) and 15 ceramic-polyethylene (average duration of 0.6 years; 0.1–1) hip arthroplasties as well as 75 native hips.

Analysis of the data enabled us to tell the difference between patients whose native hips did not cause them any discomfort and those patients with painful osteoarthritis (initial findings indicate that OA severity can be quantified as well). The measurements of wear of the metal-polyethylene prostheses obtained from patients’ x-rays were compared to an analysis of the ultrasonic emissions, a homogeneity showed no significant differences (all p’s > 0.24) between the curve type and amount of wear of the prosthesis polyethylene.

Our data suggests that we are capable of assessing the status of OA by acoustic emission. Further analysis of wear data coupled to ultrasonic emission is needed for accurate quantification of THA wear.


H. Ohashi M. Matsuuta Y. Okamoto F. Inori Y. Okajima H. Tashima K. Kitano

In image-free navigation system, three bony landmarks (typically both anterior superior iliac spines (ASIS) and pubic symphysis) are registered intraoperatively by manual palpation. If the registration of bony landmarks is inaccurate, the final orientation of the cup determined by the navigation system will also be inaccurate. We therefore examined intra-and intersurgeon variability in registration and the distance between registration points in each bony landmark with two surgical positions.

Thirty-seven THAs were performed in the lateral position and 15 THAs were performed in the supine position. The cup was fixed using the image-free Ortho-Pilot hip navigation system (B. Braun Aesculap, Tuttlingen, Germany). The registration was repeated two more times by operator and assistant, and the intra-and intersurgeon variability of cup abduction angle and anteversion was analyzed by ICC (intraclass correlation coefficients). In 25 hips, the distance between intrasurgeon registration points and that between intersurgeon registration points in each landmark were calculated.

The ICC in the lateral position ranged between 0.59 and 0.81, and between 0.85 and 0.95 in the supine position. The ICCs of cup abduction angle for the intra-and intersurgeon variability were 0.92 and 0.95 for the supine position and 0.65 and 0.59 for the lateral position. Those of anteversion were 0.93, 0.85, and 0.81, 0.72, respectively.

The variability of registration of collateral and contralateral ASIS in the lateral position was greater than that in the supine position.

In image-free navigation system, the variability of registration points depended on bony landmarks and patient position. The registrations of pubic symphysis in the supine position and all bony landmarks in the lateral decubitus position are standing further improvement.


J.P. Kretzer E. Jakubowitz K. Hofmann C. Heisel R. Sonntag E. Lietz

Knee wear simulator studies are performed to evaluate wear behavior of implants.

Simulation of the human gait cycle is often carried out continuously, without considering resting periods as they are part of patient’s daily live. In addition to dynamic activities like walking, daily activities also consist of static periods like standing, sitting or lying. During the day dynamic activities alternate continuously with static periods and most of the day is spent in passive periods, where no joint motion occurs. Such resting periods have not yet been considered in prosthetic knee wear tests. Implementing resting periods may cause an increase in friction and thus increased wear of the implant. The aim of the current study was to determine if the implementation of resting periods would increase polyethylene (PE) wear in total knee replacement (TKR).

Two wear studies were conducted using a force controlled AMTI knee simulator on a conventional bicondylar TKR. For the first study, simulation was carried out continuously according to ISO 14243-1. For the second test, four active gait cycles according to ISO 14243-1 were followed by one resting period cycle. In both tests 5x10E6 active load cycles at a frequency of 1 Hz (resulting in additional 1.25x10E6 pause cycles for the second test) were applied. Wear was measured gravimetrically and wear scars were documented photographically.

The mean wear rates measured 2.85 ± 0.27 mg/10E6 cycles for the ISO test without considering resting periods and 2.27 ± 0.23 mg/10E6 cycles for the test with resting periods implemented. There was no significant difference (p=0.22) in wear rate between both tests.

The inserts showed similar wear scars in both tests and no relevant differences in dimension and localization on the surface. Therefore the wear behavior after the two tests was similar.

Since wear is one of the most limiting factors for implant longevity, proper preclinical wear studies are essential. Based on the results of this experimental wear study, a continuous simulation without additional resting periods seems to be valid in wear simulation of TKR.


Anthony S Unger Randall J Lewis

A monobloc porous tantalum acetabular cup with a 28mm internal diameter was employed in 397 primary total hip replacements between August 1997 and December 2003. All patients were personally examined at yearly intervals for 3 years following surgery and at 2 year intervals thereafter. Thirty-one patients were known to have died and 69 hips were lost to follow up less than three years following implantation, leaving 297 hips (81%) available for review up to 10 years following implantation.

The mean age at surgery was 66.2 years, with 12% of patients aged 80 years or older. 58% of the patients were female and 42% male. 82% of the patients had osteoarthritis. Clinical and radiographic data were analyzed for patients followed for a minimum of 3 years. Mean follow up was 5.4 years. The mean preoperative Harris hip score was 31, increasing to 89 at last follow up.

The most common complication was dislocation. Eleven patients had dislocations in the early postoperative period: 4 required closed and 2 open reduction, and five required revision of the acetabular component for recurrent instability. Three patients (4 hips) with severe rheumatoid arthritis developed late instability and required acetabular revision. Four patients had a femoral fracture, 2 of which healed with slight settling and 1 of which required open reduction, subsequently became infected and required removal of the prosthesis. There was 1 superficial and 2 additional deep infections, one of which required component removal. Two patients had a fracture of the greater trochanter and required internal fixation. Four femoral components loosened, of which 3 were revised, all without involvement of the acetabular component.

There were 3 transient sciatic nerve palsies; one resolved completely and two partially, although all 3 were lost to follow before 3 years.

The porous tantalum monobloc acetabular components performed remarkably well at up to ten years following implantation. There were no instances of clinical or radiographic loosening, no osteolysis and no measurable wear visible on postoperative radiographs. The highly porous tantalum achieved reliable bony ingrowth in all cases. We hypothesize that the direct compression molding of the polyethylene into the porous tantalum substrate eliminated the backside wear and the flexion of the polyethylene liner that occurs in modular cups.


Y. Nakanishi T. Takashima H. Higaki E. Kamiyama H. Miura Y. Iwamoto M. Touge T. Umeno K. Shimoto

An artificial articular cartilage is being investigated for use in joint replacement. The low elastic modulus lining on the bearing surface is used to promote a continuous lubricant film between the articulating surfaces and hence reduce both friction and wear.

Polyvinyl formal (PVF) as an artificial articular cartilage was proposed to prolong the service life of joint replacement. The major raw material of the PVF was a polyvinyl alcohol (PVA) hydrogel, which was one of the few polymers with hydrophilic properties. It is anticipated to realize a wide range of clinical applications due to its high water-holding capacity and high biocompatibility. However, a major problem with PVA hydrogel is its low wear resistance. The PVF was made by performing a chemical cross-linking reaction in PVA, and its pore diameter, porosity, and beam density could be controlled by varying the concentrations of cross-linking agent (formaldehyde) and catalyst (sulfuric acid).

The knee joint simulator was used for investigating the wear performance of the PVF. The load and motion cycles were taken from ISO 14243-3. The peak load was 2.6 kN, and the walking cycle was 1.0 seconds. The lower PVF specimen represented the flat tibial component of the joint, and the femoral component was artificial knee joint which made from Co-Cr-Mo alloy. The lubricant was a waterbased liquid containing the principal constituents of synovial fluid.

The PVF survived for more than 1.0 million cycles. Enlargement of the PVF creep deformation by prolongation of simulating time was not obvious. Although the tribological property in fatigue wear produced by ploughing friction was inadequate, it was obvious that the PVF was a potential material for developing a load bearing system with hydration lubrication.


Matsuura H Ohashi Y Okamoto Y Okajima T Kataoka H Tashima K Kitano

Direct anterior approach (DAA) is an inter-muscular approach that needs no muscle detached. In THA through DAA approach, exposure of the acetabulum is facilitated, while the key points of this approach are femoral lift-up and hip extension to get sufficient access to the femoral canal. To investigate the strategy for femoral lift-up, we released the capsule step by step and measured the distance of femoral lift-up at each step in cadavers and clinical cases. The effects of hip extension on femoral lift-up were also evaluated.

Three fresh frozen cadavers were used. In supine position, the hip joint was exposed through DAA by two experienced surgeons. After anterior capsulotomy and femoral head resection, posterior capsule release was performed followed by superior capsule release in one side, and superior release was followed by posterior release in the other side. Finally, internal obturator muscle was released in both side. At each step, the distance of femoral lift-up was measured under the traction force of 70N. The effects of hip extension were investigated in 0, 15 and 25 degrees hyper-extension. Thirty-six THA were performed through DAA. Posterior capsule release was performed followed by superior capsule release in 13 hips, and superior release was followed by posterior release in 23 hips. At each step, the distance of femoral lift-up was measured under the traction force of 70N at each step same as the cadaver study.

In cadaver study, anterior capsulotomy and posterior capsule release affected little the femoral lift-up. The distance increased after superior capsular release. The distance decreased as hip hyperextension unless the superior capsule was released. The effect of internal obturator muscle release was not observed. In clinical studies, the same tendency was observed in clinical cases. Superior capsule release was the most effective for the femoral lift-up.

The results of this study indicate that superior capsule release is the first step for the femoral liftup. The second step is hip extension to get access to the femoral canal. By performing these procedures step by step, rasping and stem insertion can be achieved with minimal soft tissue release.


D.A. Dennis D.R. Johnson K. Kindsfater R.H. Kim

Introduction: Obtaining accurate anatomic and mechanical alignment in total knee arthroplasty (TKA) is correlated with improved long-term results. Whether computer-assisted total knee arthroplasty (CAS-TKA) more reliably produces a neutral mechanical and anatomic alignment and improves functional outcomes over traditional total knee arthroplasty (T-TKA) remains debatable. This report evaluates the results of CAS-TKA vs. T-TKA in a series of patients who underwent bilateral TKA performed at the same surgical operation.

Methods: Sequential bilateral TKA were performed on 36 patients utilizing CAS-TKA in one knee and T-TKA in the contralateral knee by two high volume, fellowship trained surgeons. A review and statistical analysis of prospectively collected data was performed after a mean follow-up of 2.2 years.

Results: Knee Society Scores (KSS) improved from 42.9 to 96.3 in the CASTKA group vs. 46.0 to 94.8 in the T-TKA group. Range of motion (ROM) improved from 116.8° to 126.9° in the CAS-TKA group vs. 118.3° to 125.4° in the T-TKA group.

With numbers available, there were no differences between the groups with regard to change in KSS (p=0.38), ROM (p=0.42), mean postoperative anatomic alignment (5.78° vs. 5.50°, p=0.37), femoral angle (5.56° vs. 5.61°, p=0.84), or tibial angle (89.89° vs.

89.69°, p=0.46). There was a non-significant trend towards fewer outliers in the CASTKA group with respect to anatomic alignment (2.8% vs. 13.9%, p=0.09) and tibial angle (0% vs. 5.6%, p=0.46).

Conclusion: There is not an apparent benefit to the use of CAS-TKA with regards to KSS, ROM, or alignment in the hands of high-volume, fellowship-trained total joint specialists. The clinical relevance of the non-sig-nificant trend towards fewer outliers in the CAS-TKA group is unknown at the current follow-up interval. These results may not preclude the benefits of CAS-TKA in lower-volume or less experienced TKA surgeons.


R.H. Kim G.R. Scuderi D.A. Dennis

Introduction: Total knee arthroplasty (TKA) in patients with skeletal dysplasia is challenging due to the anatomic variances and deformities. The purpose of this review is to understand the technical issues involved in treating these patients.

Methods: Clinical notes, operative reports, and radiographs were retrospectively reviewed of 12 knees in 8 patients: 3 achondroplasia patients (one with bilateral 10° varus deformities, one with a 30° varus deformity in one knee and 25° varus deformity in the other knee, one with a 14° varus deformity); 3 multiple hereditary exostosis patients (one with bilateral 45° valgus deformities, one with a 45° valgus deformity in one knee and 15° valgus deformity in the other, one with a 11° valgus deformity); and 2 osteogenesis imperfecta patients (one with a 25° varus deformity, one with a 17° valgus deformity).

Results: Surgical exposure required preoperative placement of soft-tissue expanders to avoid wound complications (1 knee), quadriceps snip (2 knees), and hardware removal (1 knee). Intraoperative balancing of the knee was more complex requiring a lateral epicondylar osteotomy (3 knees), medial release (6 knees), lateral retinacular release (6 knees), and proximal realignment to improve patellar tracking (1 knee). 5 knees required a constrained insert, 2 required tibial augments, one required use of cement and screw technique, and one required modification of an all-polyethylene tibia to accommodate the deformed tibial anatomy. 2 knees required custom tibial components. Complications included 2 peroneal nerve palsies which resolved 3 months postoperatively. Range of motion preoperatively averaged 103° (range 45 to 130°) and 100° postoperatively (range 85 to 120°). All patients were pain-free at their last followup (average follow-up 3.9 years).

Conclusion: Special considerations must be made regarding surgical exposure, ligament balancing, implant selection, and anticipation of complications due to the unusual deformities when performing TKA in skeletal dysplasia patients.


Joseph F. Fetto Chris Leslie

Soft tissue balancing of the “flexion gap” has a direct affect on patello-femoral tracking. Both of which are necessary for a well functioning Total Knee Arthroplasty (TKA). Traditionally, successful restoration of soft tissue balance and patellar tracking depend heavily on surgeon experience, empirical judgment and technical skill.

Orthopaedic residents often are confronted with the challenge of learning to perform TKA without objective measures with which to assess the accuracy of their surgical technique. Also, the vast majority of TKA’s are performed by surgeons who do less than 25 TKA’s per year. Both populations often rely upon surgical release of the lateral patellar retinacular tissues in order to restore “optimal” patellar tracking. This surgical technique is often associated with division of the lateral geniculate vessels and increased potential for avascular necrosis of the patella and lateral subcutaneous hematoma. Both groups of surgeons would be well served if there were available a means with which they could objectively measure whether or not they have in fact achieved the soft tissue balance they intended and optimal patello-femoral tracking, without the need for a lateral release.

Historically, the incidence of lateral release, as a means of improving patellofemoral tracking, has been reported performed in more than 10% of TKA. A prospective group of 200 consecutive TKA’s, performed by two surgeons, in which an electronic means of assessing “flexion gap” balance was retrospectively reviewed for the incidence of intra-operative lateral release. It was found that use of electronic measurement to assure “flexion gap” balance was associated with a significant reduction in the incidence of lateral release required to achieve optimal patello-femoral tracking.


Rick B. Goding

Introduction: Computer navigation has been shown to improve rotational alignment, angular alignment and sizing, when compared to a conventional jig based approach. These studies have all looked at post operative radiographic evaluation as the indicator. This study measures the intraoperative difference between the conventional jig based approach and the computer navigated system.

Methods: 59 total knee arthroplasties were performed by a single surgeon between September 2006 and February 2007. The author was trained in this technique during fellowship and has performed over 250 CAOS total knee replacements. All knees were DePuy PFC sigma implanted with the DePuy Ci system using Brain-lab software. The femoral sizing was performed using the jig after the distal femoral cut had been made using the navigation system. The difference between the size recommended by the jig was recorded. The implant was chosen by the computer recommendation, and the jig was used only for data collection. The tibial jig was then placed in the standard fashion using an extramedullary jig. The navigation marker was then placed into the jig slot, and the varus/valgus, posterior slope, and resection height were recorded using the computer modeling as the reference. The jig was then re-aligned if the computer measured angle was greater than 2 degrees in any plane, or the resection height was greater than 2mm. The cut was made using the computer recommended position if the differences exceeded these parameters. Tibial plate size was obtained using the “best fit” technique even if that differed with the computer recommendation. All post operative x-rays were then evaluated with x-ray and obvious outliers in size or angulation were recorded.

Results: One tibia was too short to be measured with a jig, so the N for tibial data is 58.

Average measured difference in varus/valgus was 1.26 degrees with 53 valgus (range 0–3.5) and 5 varus (range 0–3.6). Tibial slope average difference was average 2.31 degrees with 54 posterior (range 0–6.5 degrees) and 4 anterior (range 1–2.5 degrees). Tibial resection height difference was average 3.31mm with 4 measured high (0–3.5mm) and 54 measured low (0–6.9mm). Femoral sizing using the jig correlated with the expected size using CAOS in 28 of 34 (82%) of cases. Tibial size “best fit” correlated with CAOS in 46 of 58 cases (84%). The tibial jig was repositioned in 20 of 58 (35%) cases prior to making the cut. No tibial or femoral re cuts after the original cut were required in any case. Without using specific measurements, all post op x-rays had satisfactory alignment and component sizing, however 2 tibial plates had mild lateral overhang.

Discussion: The data suggest that in most cases, the jig approach is satisfactory, however, the computer prevents outliers. The more preoperative deformity was present, the greater variation between the measurements. The femoral jig in the conventional system we used, does not take into account femoral width, and there is no way to correct for posterior condyle deformity, this is why it is felt that the femoral fit is better with the CAOS system. Femoral rotation would not be able to be measured without using the intramedullary jig, so this step was bypassed, but if femoral rotation followed the other data, the computer would prevent malrotation in some cases. Had the conventional jig been used, the data suggests that at least one patient would have had anterior slope of the tibial tray. One patient had a tibia that was too short to use the conventional extramedullary jig. Since no intra-medullary jig was available on the set, the tibia would have had to be placed freehand if the CAOS system was not available. These data suggest that the CAOS system is preventing erroneous cuts in some cases confirming the data published regarding radiographic evaluations with respect to a decrease in the number of outliers.


T. Murakami K. Nakashima Y. Sawae N. Sakai S. Yarimitsu

The reduction of both friction and wear is required in existing joint prostheses composed of ultra-high molecular weight polyethylene (UHMWPE) and metallic or ceramic components, or even in Hard-on-Hard joint prostheses. In contrast, the healthy natural synovial joints with rubbing surfaces of articular cartilage are likely to operate at very low friction and low wear for the entire lifetime in the adaptive multimode lubrication mechanism, in which various lubrication modes become effective in various daily activities. Therefore, to establish a similar lubrication mechanism in joint prostheses by the application of compliant artificial cartilage, we conduct various researches to improve lubrication modes resulting in reduction in both friction and wear. In this paper, the effectiveness of the hydrogel artificial cartilage of high water content is discussed from the viewpoint of bionic design to mimic natural synovial joints.

The aim of this paper is to facilitate a function based on multimode lubrication mechanism in joint prostheses similar to natural synovial joints. Firstly, the possibility of full elastohydrodynamic lubrication was evaluated by experimental methods in friction tester and joint simulator. The joint prostheses with compliant rubbing materials or polymer-on-hard joint with better geometrical congruity showed siginificant fluid film formation, but some local intimate contact occurred. Therefore, as the second viewpoint, the effectiveness of adsorbed film formation was examined. The noteworthy phenomena are remarkable reduction in friction for artificial joint with poly(vinyl alcohol) (PVA) hydrogel articular surfaces and a notable increase in friction for artificial joint with polyurethane surface in hyaluronate solutions containing serum proteins. These results indicated that adsorbed protein films can reduce or increase friction and wear depending on probably fluid film thickness.

Other findings of effectiveness of layered adsorbed film and negative effect of heterogeneous adsorbed film are described on the basis of various observation in friction tests.

As the third viewpoint, the importance of biphasic lubrication and hydration lubrication for hydrogel surface with high water content is discussed. In friction tests of natural articular cartilage against glass plate, it was observed that the unloading for 5 min after continuous 30 min rubbing reduced the friction at restarting probably due to biphasic lubrication and/or hydration lubrication after rehydration, where adsorbed films have some influences on friction and wear. For joint prostheses with compliant hydrogel artificial cartilage, similar mechanism is required for surface and bulk structure of artificial cartilage.

In this paper, several important essential points from the bionic design are indicated for development of the next generation for joint prostheses with higher function and better longevity.


J. Zelle M. De Waal Malefijt N. Verdonschot

High-flexion knee replacements have been developed to accommodate a large range of motion (ROM > 120°) after total knee arthroplasty (TKA). Femoral rollback or posterior translation of the femoral condyles during knee flexion is essential to maximise ROM and to avoid bone-implant impingement during deep knee flexion. The posterior cruciate ligament (PCL) has been described as the main contributor to femoral rollback. In posterior-stabilised TKA designs the PCL is substituted by a post-cam mechanism. The main objective of this study was to analyse the mechanical interaction between the PCL and a highflexion cruciate-retaining knee replacement during deep knee flexion. For this purpose, the mechanical performance of the high-flexion cruciate-retaining TKA design was evaluated and compared with two control designs including a highflexion posterior-stabilised design.

Materials & Methods: Prosthetic knee kinematics and kinetics were computed using a three-dimensional dynamic finite element (FE) model of the knee joint. The FE knee model consisted of a distal femur, a proximal tibia and fibula, a quadriceps and patella tendon, a non-resurfaced patella, TKA components and a posterior cruciate ligament in case cruciate-retaining designs were evaluated. Tibio-femoral and patello-femoral contact were defined in the FE knee model and the polyethylene insert was modelled as a non-linear elastic-plastic material. Three different rotating platform TKA systems were analysed in this study: the high-flexion cruciate-retaining PFC Sigma CR150, the high-flexion posterior-stabilised PFC Sigma RP-F and the conventional cruciate-retaining PFC Sigma RP (Depuy, J& J, UK). Both the polyethylene stress characteristics and the tibio-femoral contact locations were evaluated during a squatting movement (ROM = 50° – 150°).

Results: During deep knee flexion (ROM > 120°), the high-flexion cruciate-retaining TKA design showed a lower peak contact stress (74.7 MPa) than the conventional cruciate-retaining design (96.5 MPa). The posterior-stabilized high-flexion TKA design demonstrated the lowest peak contact stress at the condylar contact interface (54.2 MPa), although the post was loaded higher (77.4 MPa). All three TKA designs produced femoral rollback in the normal flexion range (ROM ≤ 120°), whereas the cruciate-retaining designs showed a paradoxical anterior movement of the femoral condyles during high-flexion.

Discussion: PCL retention is a challenging surgical aim and affects the prosthetic knee load and kinematics as shown in this study. In addition, for adequate functioning the PCL should not be too tight or too lax after surgery. Hence, we investigated the effect of PCL laxity on the prosthetic performance and the best-balanced PCL was used in our simulations. Although PCL balancing is not an issue for posterior-stabilized TKA, we found the tibial post to be loaded relatively high for this implant type.


G. Pezzotti

Total hip arthroplasty (THA) represents a very spread and effective surgical procedure. Surgeons and technologists make daily efforts in improving the outcomes of THA, with the ultimate goal of creating a prosthesis that reliably lasts at least as long as a human lifetime. While the results of primary hip arthroplasty are generally very good, revision surgeries might score variable success with regards to their clinical outcomes. In addition, they invariably represent an expensive procedure and a severe burden to the patients. Thus, a reduction of the failure rates of only a few percents can, due to the large number of patients involved, have a vast influence on the accumulated costs and patient suffering. In other words, the key issue in hip arthroplasty resides in the improvement of the prostheses with regard to their long-term in vivo reliability. These circumstances amply justify a continuous search for new hip prostheses with improved structural characteristics and elongated lifetimes.

Most recent innovative trends in THA have focused on the improvement of the tribological behavior of hip joints and challenged the achievement of a longer durability, with the potential for a service-life spanning several decades. Such trends have naturally led to an increase in the use of ceramic materials, either as ceramic femoral heads yet coupled with advanced acetabular cups made of polyethylene (i.e., with improved molecular structure and quality), or as ceramic hip components for both acetabular and femoral bearing surfaces. The greater driving force in using ceramic bearings is their potential of systematically reducing periprosthetic osteolysis (i.e., mainly arising from polyethylene wear debris), which could potentially reduce the number of surgical revisions. The high inertness and biocompatibility of ceramic materials may also reduce to a minimum the collateral effects on the human body, as possibly observed with metallic prostheses (e.g., contamination by metal ions, hypersensitivity, etc.). Despite those advantages, chipping and fracturing have severely limited the popularity of ceramic components. As a further issue, it should be noted that ceramic-on-ceramic articulations strongly require high precision in setting the orientation of the components during surgery (in order to avoid excessive impingement on the ceramic surface). Partly fractured ceramic bearings necessarily dictate revision. The main reason is that the ceramic remnants in the articulation would give rise to severe third-body wear, especially in the presence of a softer bearing counterpart. Clearly, ceramic components offer a very high potential for further improving both structural performance and lifetime of hip joints but, being made of fragile materials, they also require significant progress in surgery technique, further advancements in joint design and materials manufacturing processes, as well as a peer non-destructive control of their structural reliability.

In this presentation, we shall first have a brief survey on the main cases of failure in the recent history of hip prostheses. Then, a description of the most advanced and recent technological approaches to material preparation, reliability control and non-destructive analysis of hip components will also be given. The main aim of this presentation is to drive the attention of the international orthopaedic community on the need for a highly interdisciplinary approach to the study of hip joint arthroplasty. In this context, we provide here some vivid examples of how newly developed Raman spectroscopic methods may provide final solutions to historical problems related to the chemical and structural reliability of materials widely employed in total hip arthroplasty.


H. Haider O. A. Barrera K. L. Garvin

Computer aided orthopaedic surgery (CAOS) systems aim to improve surgeons’ consistency and outcomes by providing additional information and graphics, often displayed on one or more computer screens. Experience has shown that surgeons often feel uncomfortable looking away from the patient to focus on the computer screen, and multiple methods have attempted to address this (e.g. by using head mounted and semi-transparent displays). We present a new approach, with a small touch-screen wirelessly controlled from the main CAOS computer and micro-controlled electronics all mounted on the cutting instrument and placed along the surgeon’s line of sight from the instrument to the wound. In addition, the micro-controlled system improves the patient’s safety by controlling the cutting speed of the blade (or stopping it), based on the saw’s positioning deviations from the planned cuts. The (on board the saw) computer-user interface also transmits commands to the main computer, based on commands issued on the touch screen.

The “smart” navigated saw was built by integrating a microcontroller, optical trackers, a small 4x6cm viewable touch-screen, and a surgical oscillating saw. Bidirectional wireless communication was established between the saw and a Navigated Freehand Cutting (NFC) CAOS system allowing dynamic speed control of the blade, slowing it down for smaller errors in position/alignment (relative to planned cuts), and stopping it for bigger errors and/or risk of tissue damage. The sensitivity of the correction and width of the allowed error envelope were made adjustable to cater for the individual surgeon preferences. The touch-screen on the saw provided the surgeon with a visual aid for cutting without them having to look away while simultaneously providing control of the interface settings by touch. After electronic bench tests, two orthopaedic residents prepared eight synthetic distal femurs with the NFC system and the prototype saw to accept a commonly used TKR implant.

All parts were integrated into a usable stand-alone device, with no software, hardware, or logical failure registered during the tests. The speed control responded to the established threshold errors and the preferred dynamically adjustable settings were found to be 0.5mm to 10mm of error in location and 0.5° to 10° in pitch or roll angle. The surgeons were satisfied with the user-interface for graphical guidance and system control. No significant difference in implant alignment, fit and cutting time were found compared with the standard NFC system with standard size computer monitors.

By a wireless link between a CAOS system computer and the cutting instrument (with a graphical touch display screen on board), the patient’s safety and surgeon’s visibility needs were addressed allowing the screen to be aligned with the wound. With a user interface on the saw, and automatic speed and stopping control of the cutting instrument based on navigation, the surgeon is prevented from cutting in the wrong place. This surgeon-actuated but “software cutting jig” fulfils the same functions of cumbersome autonomous or passive surgical robots with their sophisticated servo and haptic interfaces, but with startling utility bringing in the era of the modern “smart” hand-held bone cutting instruments.


K. L. Garvin O. A. Barrera H. Haider

Computer aided orthopaedic surgical (CAOS) technology has been around for over 20 years, and while it appears to provide better outcomes compared to conventional jigs, less than 1% of orthopaedic surgeons in USA have adopted it. This study surveyed the arguments against CAOS usage, highlighting those reasons which may continue to prevent CAOS from becoming truly widely accepted.

The survey has identified several concerns with navigation systems. For example, the pin tracts from navigation reference frames cause stress risers that increase the risk of bone fracture and soft tissue/muscle damage. Additionally, infrared trackers take footprint space (as they require line of sight access to the tracking camera), increase risk of infection, and present a potential distraction to the surgical team. With current CAOS systems, even more nstrumentation is needed than with non-navigated surgical systems, and it is arguable that navigation makes surgery more complex, requiring a knowledge of anatomic landmarks, an increased number of tasks prior to and during surgery, and an assortment of different and perhaps unfamiliar instruments. These complexities very likely result in a slow learning curve on current CAOS systems, a learning curve that is mostly not started by the majority of surgeons.

Other items of concern are the accuracy of morphed/generated bones in imageless systems (and how these models assume non-deformed anatomy), inaccuracies or distortion of the measurements (operating room lighting interfering with infrared trackers or field deformation of electromagnetic systems due to ferromagnetic instruments at the surgical site) and computer reliability. Considering the high cost (or low cost-effectiveness) of integrating CAOS into arthroplasty, and the lack of enough studies documenting truly better long term clinical results or fewer actual complications, it is evident why navigation is not yet a popular option for TKR.

As a result of the critical findings from this study, it is our view that any successful new technique/tool in surgery should make the overall procedure easier, faster, cheaper and better (or at least equally as good) as the current techniques. While robotic surgery seems to be re-emerging, we hypothesize that the next real breakthrough will come from newer more utilitarian light weight small foot print technologies actuated by surgeons themselves, with enhanced computer guidance that will allow them to reduce instrumentation, complexity, and surgical time such as navigated free-hand bone cutting. Alternative navigation technologies (e.g. UWB 3D positioning radar) where line of sight becomes less crucial, image based systems (rather than image free), artificial vision, and smart instrumentation are likely to play a major role in achieving widespread future acceptance of CAOS in TKR.


M. Browne O.J. Coultrup C. Hunt M. Taylor

Orthopaedic implants are often fixed into place using bone cement. The degradation of the cement mantle has been implicated as playing a major role in the loosening of these implants, and this often necessitates revision surgery. The present work has used the non-destructive acoustic emission (AE) technique to monitor the initiation and evolution of fatigue damage in bone cement constructs. Using this technique, it should be possible to gain an understanding of failure progression in cemented orthopaedic devices. Previous work in this area has focused on AE activity originating from the eventual failure location in order to identify those signatures associated with critical fatigue cracks. This usually involves analysing AE signatures associated with the final stages of failure; however, there have been limited investigations that have looked at the damage that takes up most of the crack propagation life of the sample, (i.e. microcracking formation and development), that occurs away from the failure site, but could still play a role in final failure.

In this study, dog-bone-shaped specimens of bone cement were subjected to uniaxial tensile fatigue loading, with damage monitored along the length of specimens using AE. Where specimens exhibited AE activity at locations away from the fracture site, they were sectioned and subjected to synchrotron tomography, which enabled high resolution images of these regions to be obtained. Microcracks of the order of 20 microns were observed in areas where AE had identified early, non-critical damage; in contrast, no microcracking was observed in areas that either remained unloaded or exhibited no AE. To further corroborate these observations, and characterise the damage mechanisms involved, scanning electron microscopy (SEM) was applied to the sectioned samples. In those locations where significant yet non-critical AE occurred, there was evidence of crack-bridging, suggesting that crack closure mechanisms may have slowed down or even arrested crack propagation within the bone cement.

These findings further validate the use of AE as a passive non-destructive method for the identification and understanding of damage evolution in cemented orthopaedic devices.


O. A. Barrera K. L. Garvin H. Haider

Formal surgical skill assessment and critical path analysis are not widely used in orthopaedic surgical training due to the lack of technology for objective quantification, reliability, and the discrimination insensitivity of existing methods. Current surgical skill assessment methods also require additional instrumentation, cost and time. Such problems can be overcome by a novel method that records the motion of surgical instrumentation for the purposes of documentation, surgical-skill assessment, and safety analysis. This method uses an existing computer-aided-orthopedic-surgery (CAOS) navigation system and does not compromise its functions of real-time tracking, rendering, or simulation. The stored data allows realistic playback in 3D of the complete bone cutting/refining process. This concept and its sensitivity were previously tested and validated using a robotic arm as a reliable actuator for a surgical instrument moving in controlled paths. In this study, the system was used to evaluate the surgical skills of actual orthopaedic residents in a hospital/lab setting.

Two chief orthopaedic surgery residents participated in the experiment. Each one cut all five distal cuts on four synthetic (right) femurs to accommodate the same femoral implant using NoMiss, an in-house built system for Navigated Freehand bone cutting. The motion of the surgical saw was recorded in real time by NoMiss during the whole procedure, but the real purpose of the experiment (and the recording) was not revealed to the residents until the end of all tests. Based on the data recorded by the navigation system, the following parameters were analyzed: cutting time, area-of-the-cut/time ratio, trajectory of the saw, errors in distance off the plane as well as errors in roll and pitch angles.

While no significant difference among the two subjects was found in bone cutting time (mean 531s vs. 642s, p=0.099), subject 1 (S1) was faster than subject 2 (S2) in total time, which included cutting, reshaping of the bone, and implantation (mean 719s vs. 958 s, p=0.035). Area-of-the-cut/time ratio revealed higher (not significant) proficiency for S1 compared to S2 (mean 16 mm2/s vs. 13 mm2/s, p=0.084). Nevertheless considering individual cuts, there was significant difference in the posterior chamfer cut (mean 9 vs. 5 mm2/s, p=0.015). The analysis of the trajectory of the saw showed less conservative motion (and less consistency) for S1 than for S2 (average total length of trajectory 8.6m (sd=2.1m) vs. 8.1m (sd=0.4m), as well as larger paths in between cuts (average 39% vs. 33% of the total trajectory).

The system/method was able to characterize different subjects without additional instrumentation, cost, time, awareness of or distraction to the user. Slightly better performance was detected for S1 compared to S2 presumably signifying superior skills. The main differences in this case appeared in the cutting of the chamfers, which might be considered the trickiest of the distal cuts in a navigated freehand cutting environment. A larger number of subjects with a wide level of expertise should be analyzed under similar conditions to establish quantitative acceptance limits (e.g. numerical determination for pass/fail criteria).


S. Kreuzer

The ability to reliably balance a total knee replacement during surgery eliminates a number of postoperative issues often leading to recurrent joint pain and lower than expected clinical outcomes. Over the past few years a surgical instrument has been available to surgeons performing primary TKA’s to enhance their surgical ability to develop flexion space balance by customizing femoral rotation by developing equal relative forces in the medial and lateral femoral-tibial compartments instead of using rotational anatomic landmarks. Since this concept deviates from the current practice of using anatomic or “boney” landmarks, as in the TEA or AP axis to develop a balanced flexion space with femoral rotation, this study design evaluated the variation in femoral rotation between the force balanced rotation and the conventional external rotation developed from the TEA and AP axes. Using the premise from previous studies that; clinical instability presents itself when the flexion space is asymmetric by more than three degrees, data was analyzed on 50 total knee patients to establish the rotational difference between the force balanced rotation and the rotation using the two conventional axes. Computer navigation was used as the measuring tool in this study.

The study results showed that flexion space asymmetry would have been greater than the targeted three degrees in 38% of the knees in the study when utilising conventional anatomic reference based femoral rotation. The force balanced rotation created additional external rotation from a half to three degrees in these knees, improving patellar tracking.

Based on previous work evaluating laxity in total knee patients, the reliability offered by force sensing technology appears to improve the surgeon’s operative ability to balance a reconstructed knee within three degrees of symmetry in flexion. This new technique appears to improve reported postoperative complications associated with instability in a reconstructed total knee. Further studies utilizing CT scan data to validate the actual femoral rotation and clinical outcome studies are warranted to examine this potential improvement to clinical outcomes in primary TKA’s.


Russell Nevins

One of the main reconstructive objectives in a primary TKA is to develop a well balanced knee by focusing on establishing flexion symmetry during the procedure using external femoral rotation. Current surgical techniques rely on anatomic or “boney” landmarks, including the posterior condylar axis, AP axis and Transepicondylar axis (TEA), to accomplish this objective. Variability in using these anatomic references has been sighted in published studies on the subject and clinical complications associated with joint instability continue to surface in the literature. A main reason for this variability is the fact that functional ligament and soft tissue support is not interpreted early enough in the procedure when using anatomic landmarks. This can make correcting flexion symmetry challenging later in the procedure given soft tissue releases vary in their end result. To address this issue, an electronic force sensing technology has been used to balance the flexion space for the past 24 months. This simple reproducible technology utilises a soft tissue force sensing device to develop flexion symmetry by creating balanced external femoral rotation relative to the proximal tibial resection. The sensor and adjustable femoral trial-like device enable balancing the relative forces in the medial and lateral femoral-tibial compartments in the knee to establish symmetry in flexion before the implant trials are placed. This step is performed early in the procedure before the posterior femoral condyles are resected, a technique delivering reliable results covering a broad range of deformities. Since the sensor relies on relative force values cued from the medial pillar, the question of “how tight is just right” needs to be answered to further optimise outcomes.

The current study involves 50 posterior stabilised rotating platform primary knees. Data on operative variables was collected and tibial spacers of different thicknesses (matching implant system thicknesses) were introduced into the balanced flexion space to register relative force values. The thickest tibial spacer creating balanced function and ROM was recorded first and the next thinner spacer recorded for comparison. Oxford Knee scores were then collected at two weeks, six weeks and three months following the primary knee reconstruction and associated to the relative force value of the tibial insert implanted to develop functional feedback on “how tight is just right.” Early experience seems to indicate the tighter tibial insert is the better choice based on the characteristics of the knee design used in this study.

The results of this study have shed important light on tibial insert selection related to functional outcomes. Expanded study on this subject would greatly benefit future surgeons and patients alike.


W. R. Hamel R. D. Komistek D. Dennis A. Nycz

Conventional fluoroscopes are routinely used to analyze human skeletal joints during motions such as deep knee bends. Such diagnostics are used to characterize pre and post operative arthoplasty results, particularly in association with total joint replacement procedures. The pseudo-stationary conditions imposed by the fixed fluoroscope limit the diagnostic procedures to much less than natural skeletal motion and load conditions, thus diminishing the utility of the results. A new class of fluoroscopy has been developed in which a robotic mechanization is used to allow selected joints to be x-rayed while the human subjects perform natural motions such as walking. The tracking fluoroscope system (TFS) is essentially a mobile robot that can acquire real-time x-ray records of hip, knee, or ankle joint motion while the patient walks normally within a laboratory floor area. It is anticipated that the TFS will provide clearer and more representative x-ray images.

The robotic mechanization includes an untethered and omni-directional mobile platform that follows the patient as he/she walks, including negotiating stairs or ramps.

In addition to following the patient, additional control devices track the joint motions that occur relative to the patient’s body, e.g., knee joint vertical and anterior/posterior relative motion. The technical features of the TFS will be described, and test results related to the commissioning of the TFS for clinical trials will be presented. Initial clinical test results will be provided.


Constantinos Ketonis Amiethab Ayier Stephanie Barr Christopher S. Adams Irving M. Shapiro Noreen J. Hickok Javad Parvizi

Infection poses one of the greatest medical challenges, one further complicated by bacterial biofilm formation that renders the infection antibiotic insensitive. The goal of this investigation was to covalently link the antibiotic vancomycin (VAN) to a bone allograft so as to render the tissue inhospitable to bacterial colonization and the subsequent establishment of infection. We could achieve uniform tethering of the antibiotic to the allograft with minimal disruption of the underlying bone structure. The tethered VAN remained active against gram-positive organisms with no detectable S.aureus colonization. Additionally, the grafted VAN prevented biofilm formation, even in protected topographical niches. Attachment of the antibiotic to the allograft surface was robust-the stabilized VAN remained active for long time periods. Osteoblasts cultured on the VAN-allograft evidenced no changes in cellular phenotype. We opine that this new chimeric construct represents a superior transplantable substrate with a plethora of applications in medicine, dentistry and surgery.


Post-operative stability in a primary TKA procedure requires surgical skill in establishing symmetric flexion and extension spaces. Many surgeons further utilise techniques associated with “gap balancing” by attending to the dimensional space between the femur and tibia in developing flexion and extension gaps following bone resections and/or soft tissue releases. Questions still arise related to these gaps, in particular whether or not these gaps should be created dimensionally equal to each other by adjusting bone resections. Previous publications on this subject point to the conclusion that they are not dimensionally the same, but have a relationship to the supporting soft tissue in the flexion and extension positions. This study has been designed to investigate this premise.

A soft tissue force sensing device, enabling the surgeon to create accurate balanced posterior femoral condylar resections relative to the soft tissues and the proximal tibia, has been integrated into the current surgical technique to create reliable flexion gap symmetry. To extend the concept of using balanced relative force readings to a more complete gap balancing technique, a preliminary distal femoral resection is made to facilitate mounting the adjustable instrument interfacing with the force sensor. Femoral rotation is adjusted to establish a symmetric flexion space based on balancing the relative force values in the tow femoral-tibial joint compartments. This sensor guided balancing step establishes the desired tibial insert thickness in the reconstructed knee. The final distal femoral bone resection is then made to equate the extension gap to the balanced flexion gap.

Taking the concept of balanced resection to the next level, special angled inserts have been developed to fit onto the sensor and fill the extension space, in efforts to determine and create a balanced extension space.

Data was gathered to relate the relative flexion force value to the resulting relative extension force value to see how this compares in a series of TKA’s.

The results of this data will begin to shed light on the supporting soft tissue conditions when a true balanced resection technique is utilised. The focus of this study is to evaluate the extension forces resulting from this technique to better define a functional relationship between the flexion and extension gaps in the gap balancing technique.


B. Devadasan W. Loo C. Teng

CAN TKR is aimed to improve accuracy in realignment with balanced knee joint.

Variability in the force exerted during tissue tensioning depends on the viscoelastic nature of soft tissues.

Aim: To measure gap balance to assess effectiveness of CAN on ligament balance using gap balancing approach with tibia 1st cut.

Methods: OrthoPilot system with 4.3 software and Statistical evaluation with Testimate Version 6.0, IDV Gaunting Germany with a two sided Wilcoxon-Pratt test (P< 0.05) used simulating errors in extension and flexion gap balance. P1, control with 16 datasets created and P2-P7 (96 case series) was propagated with ±3mm variants in extension and flexion gap both medial and lateral, only varying 1, keeping others constant. Controls fixed: distal transverse plane cut at 0° to femoral mechanical axis in frontal plane and 3°external rotation in sagittal plane. Tibia cut 90° to mechanical axis. Mechanical axis constant at 0° and gap balance at 0 mm. Deviations in gap errors using trigonometrical calculations based on E-Motion femoral implant, size/thickness; 3/7mm and 4/8.5mm with variation of insert size 10/12mm equal to sum of gap and bone cut.

Results: Over tensioning (OT) distal lateral extension gap (DLEG) causes tight distal medial extension gap (DMEG). Under tensioning (UT) DLEG causes loose posterior medial flexion gap (PMFG). UT DLEG causes tight DLEG. Impact factor > 2mm increased PMFG with lateral lift off with only PMFG as variant. Increasing PMFG > 2mm caused lax PMFG. UT even by 1mm PMFG causes error by notching and tight PMFG. A considerable number of errors observed in frontal plane of femur.

Relationships between OT/UT analyzed by Spearman rank ratio p< 0.001.

Conclusions: Change of tissue spreader tension in EG or FG causes improper registration with mismatch in EG/FG/Bone cut. This study provides a baseline to further assess and develop the concept of optimal soft tissue balance as ligaments function properly only with the desired isometry in gap balancing technique.


N. Shimazaki N. Nakachi H. Mitsuyama Y. Konaga N. Yoshino T. Matsushita S. Takai

Newer prosthetic total knee arthroplasty (TKA) designs as well as unicondylar TKAs spare the anterior cruciate ligament (ACL). Although success of these procedures requires near normal ACL function, little has been written about the arthritic ACL.

This study was designed to evaluate the relationship between cross sections of the intercondylar notch and the macroscopic condition of ACL degeneration. Thirty osteoarthritic patients who underwent TKA as a result of severe osteoarthritis were randomly selected. Occupation rate of the osteophytes to the notch width were measured at the anterior 1/3, middle 1/3, and posterior 1/3 notche images obtained from preoperative tunnel view. Macroscopic conditions of the ACL and PCL were classified into four types of Normal, Frayed, Partial rupture, and Absent.

The macroscopic ACL conditions were Normal: 9 cases, Frayed: 9 cases, Partial rupture: 9 cases, and Absent: 3 cases. The macroscopic PCL conditions were Normal: 24 cases, Frayed: 3 cases, Partial rupture: 3 cases, and Absent: 0 case.

Occupation rate of the osteophytes to the notch correlated to the preoperative femorotibial angle (p< 0.05). In terms of ACL, the occupation rate of the osteophytes to the notch were 22.9%, 28.8%, 46.0%, and 81.8% in Normal, Frayed, partial ruptured, and Absent, respectively. The patients with more than 40% occupation rate showed either partial rupture or absent of the ACL during the surgery.

We conclude that occupation rate of the osteophytes to the notch is a good predictor of evaluating the ACL degeneration in osteoarthritic knee.


Philip Noble Adam Brekke Andrew Shimmin

Joint Registries are a valuable resource for defining the survivorship of prostheses and procedures undertaken for the treatment of joint disease. However, the use of this data as a basis for advocating specific implant designs is controversial because of the confounding effects of variations in patient selection, the training, skill and experience of surgeons, and the priorities of individual patients. Despite these challenges, the Australian Joint Registry has utilized its early survivorship data to identify specific designs that are expected to exhibit lower than average durability in the long term. The aim of this study was to assess the accuracy of this practice in identifying implants providing inferior long-term performance.

Over the period 2004–8, the Australian Registry identified 48 prosthetic components used in primary THA, HRA, TKA or UKA which exhibited a statistically significant increase in the early revision rate. For each of these components, we compared the rate of revisions per 100 “component-years” when it was first identified by the Registry, to its ultimate fiveyear cumulative survival in 2008. These survival parameters were also compared to average values based on procedure (eg.THR) and fixation method (i.e. cemented, cementless, hybrid).

Regression analysis was performed to determine the accuracy of initial relative revisions per 100 OCY as a predictive measure of eventual component revision rate.

Five year survival data was available on 30 of the 48 implants identified by the registry. There was a strong correlation (R2=0.9614) between initial revisions per 100 component-years and the 5-yr survival of the identified designs. 29 of 30 designs (97%) exhibited lower than average survivorship at 5 years. Six designs (20%) had failure rates within 2% of average values, and 7 (23%) had a 5–year failure rate less than 50% above average values. Although, when identified by the Registry, 80% of identified components exceeded the average rate of revision by 100%, only 60% displayed more than twice the cumulative revision rate at 5 years post-op.

These results demonstrate that early data collected by Joint Registries can form the basis of accurate identification of designs which ultimately prove to be clinically unsuccessful. Predictions made by the Australian Registry concerning inferior designs have an accuracy of approximately 80%. Further work is recommended to enhance the valuable potential of Registry data in predicting the outcome of both implants and procedures.


D.J. Jacofsky J.D. McCamley M. Bhowmik-Stoker M.C. Jacofsky M.W. Shrader

Total knee arthroplasty (TKA) is a common surgery to relieve knee pain and increase range of motion due to osteoarthritis (OA) in older patients. Minimally invasive, computer navigated techniques are gaining popularity for knee replacement surgery. These techniques may have potential to provide better functional outcomes over a shorter period of time. Little data exists comparing the early functional recovery of patients following total knee replacement surgery performed using various common approaches. This study compares the functional gait of patients two months after surgery performed using one of four common approaches to determine if differences exist in the immediate recovery. This knowledge will aid surgeons determine the best approach to use when performing surgery.

This study was approved by the appropriate Institutional Review Board. Subjects volunteered to participate in the study and signed informed consent prior to testing. Subjects were excluded if the had significant diseases of the other joints of the lower extremity or a diagnosed disorder with gait disturbance. Patients were randomly assigned to receive unilateral primary TKA using standard parapatellar, mini-parapatellar, mini-midvastus, or mini-subvastus approaches. All patients received the same preoperative, perioperative, and postoperative critical pathways and standard orders. All incisions were five inches and all patients and examiners blinded to type of approach. Surgery was performed by one of two fellowship trained orthopedic surgeons. Patients visited the gait laboratory two months after receiving TKA. Motion data was captured using a ten-camera motion capture system (Motion Analysis Corp., Santa Rosa, CA). Three-dimensional force data was recorded using four floor embedded force platforms (AMTI Inc., Watertown, MA). Patients were asked to walk at a self selected speed along a 6.5 metre walkway. A minimum of five good foot strikes for each limb were recorded. Data were collected using EVaRT 5 software (Motion Analysis Corp., Santa Rosa, CA) and analyzed using OrthoTrak 6.2.8 (Motion Analysis Corp., Santa Rosa, CA) and MatLab software (The Mathworks Inc., Natick, MA). Statistical analysis was performed using SPSS 14.0 software (SPSS Inc., Chicago, Il) (α = 0.05).

Fifty-two patients (72 ± 6 years) volunteered to participate in the study. The approaches used were: standard parapatellar – 12; mini-parapatellar – 12; mini-midvastus – 14; mini-subvastus – 14. Statistical analysis found no significant differences in any of the variables measured except minimum knee flexion angle during stance (p=.046). The variables measured included the maximum and minimum injured lower limb joint angles in all planes during both stance and swing phase of gait. Also measured were the maximum joint moments in all planes during stance and hip, knee, and ankle powers.

Patients who received TKA using the mini-subvastus approach had greater knee extension through much of the single stance phase of the gait cycle which contributed to a lower (but not significant) peak knee flexion moment. These patients also had the highest ground reaction shear forces with higher ankle power absorption at foot strike and generation at push off. Mini-subvastus patients used a higher cadence to walk with a greater velocity then patients who received surgery using the other approaches.

The results of this study show only minor differences in gait between patients who have received surgery using the different approaches. The limited numbers of patients in the study and the large variation in outcomes so soon after surgery mean that in most cases the differences that were measured do not reach significant level. This study shows that the surgical approach used to implant the device has no apparent effect on the ability of the person to ambulate following surgery, however further study with increased numbers of patients and observation over a longer period of time will allow a stronger conclusion. The knowledge gained from this and future studies will enable surgeons to make decisions on type of approach based on factors other than expectations of functional outcome.


Vineet Tyagi Kwang Jun Oh

Background: The purpose of this study was to assess the stability of short hip stem postoperatively using the radiographic parameters and a novel scoring system based on the unique fixation mechanism of the short hip stem system.

Materials and Methods: Postoperative radiographic analysis was done for 31 total hip arthroplasties performed using Metha® short hip stem prosthesis. The Metha® short hip stem system (B. Braun Aesculap; Tuttlingen, Germany) design provides a unique fixation mechanism, with support at the medial calcar region, lateral neck, and dorso-lateral cortical contact distally.

Additionally the modular design offers increased options and variations. We assessed the stability of stem by using a novel scoring system conceptually based on the unique fixation characteristics of the short stem design and included surgeon controlled variables like position and sitting of stem, dorso-lateral cortical contact and filling ratio of stem. The system also incorporated unmodifiable patient specific variables that ultimately render additional stability to the cementless stems in long run.

Results: The positioning of stem was within normal range in all cases in terms of anteroposterior and lateral CCD angles and horizontal offset. The mean filling ratio of stem were 93.48%±4.38% (range 82–100%). 82.75% hips had acceptable sitting of the short stem at the osteotomy site at proximal end of femur. None of the hips showed any amount of subsidence, except one with a static first follow-up subsidence of 2mm. Using our scoring system all hips showed good to excellent results, with mean score of 44.29±3.83 (range 38–50, maximum score 50).

Conclusion: Our scoring system acts as valuable tool for radiological assessment of Metha® short stem postoperatively. Furthermore, in future longer follow-up studies are required to correlate the scoring system with the longevity and stability of the endoprosthesis.


G. G. Jones J. P. Hollingdale

Minimally invasive total knee arthroplasty is purported to have a number of patient benefits: reduced post-operative pain, earlier mobilisation, and shorter in-patient stay.

However, previous literature has identified the existence of a learning curve that may render the procedure unsuitable for low-volume arthroplasty surgeons.

Via retrospective analysis, we set out to compare the incidence of major and minor complications during the first eighty-four minimally invasive total-knee replacements (NexGen; Zimmer UK) undertaken by a single high-volume arthroplasty surgeon starting in April 2004.

The eighty-four patients were sub-divided into four chronological groups (twenty one patients each, designated A, B, C & D respectively). Fifty-three patient records were available for analysis. These comprised: Group A (n=17), Group B (n= 13), Group C (n= 10), and Group D (n=13), with a mean follow-up of 21 months.

Three patients had rheumatoid arthritis, whilst the remaining fifty had osteoarthritis.

There were two major and five minor complications in Group A, one major complication in Group B, one major and one minor complication in Group C, and two minor complications in Group D. Employing a Turkey post hoc ANOVA test, no significant differences were found between the groups when comparing overall complications, or when comparing minor and major complications as separate entities (PASW Statistics 17 for Windows, Chicago, Illinois).

To conclude, although a higher complication rate was observed in this group of patients during the first twenty minimally invasive total knee arthroplasties, this difference was not statistically significant. A follow-up study will analyse the postoperative results of a more recent cohort of patients.


B. Violante M. C. Meloni

Total knee arthroplasty in last years has changing the field of applications: from old patients with low demand activities is shifting toward younger patients with higher level of activities demand.

Details are promising to more reliable outcomes. Surgeons in conjunction with orthopaedic industries are studying a new instrumentation to better fit the anatomy in M.I.S. surgery and more precise design able to reproduce the correct tensioning of ligaments. In the years, two philosophies were developing to the assess femoral rotation in total knee arthroplasty: bone references and ligament references.

The first one use the bone landmarks to assess the right femoral rotation while the second one use the ligament tensioning to assess the femoral rotation.

Both technique and instruments are able to attend good outcomes, further anatomic and biomechanical studies seem to show that the difference between the two surgical approach can be avoided. Instead of developing a new class of instruments, we put together the two philosophies giving to the surgeon more challenge to assess the femoral rotation in total knee arthroplasty. This study shows the early results with FBI instrumentation (Zimmer ins, Warsaw). We operated 24 patients using FBI instrumentation. The case load included 16 men and 8 women. The age distribution was from 63 to 75 years with a median age of 68. The operation time has been the same one of the traditional instrumentation.

So far the patients have been shown good and improved early recovery. There was not any complication during the early post-operative time.

This is use a mini soft tissue tenser good to fit in MIS surgery and a IM rod for the free femoral rotation, at same time surgeon can check the femoral landmarks (Whiteside line and epi-line) to put the two ways in conjunction and fitting better outcomes.


W. Wang T. Morrison J. Geller R. Yoon W. Macaulay

Not all patients receive enhanced mobility and return to comfortable, independent living after Total Hip Arthroplasty (THA). It would be beneficial to both surgeons and patients to be able to predict short term outcomes for THA. The purpose of this study was to investigate factors affecting the short term outcome of primary THA and develop a multivariate regression model that can predict such outcomes.

This was a prospective study of 101 patients, who underwent primary THA. All patients were followed for a minimum of 1 year. 12 independent variables, including age, gender, diagnosis, presence of preoperative comorbidities, BMI, preoperative WOMAC physical component (PC) score, type of anesthesia, type of fixation, surgical time, estimated blood loss, use of a postoperative drain, and length of stay were analyzed using correlation and multivariate regression analyses. Multivariate regression models were validated using an independent cohort.

Correlation analyses showed three variables significantly influence short term THA outcome. These include preoperative WOMAC PC score (PC) (p< 0.01), gender (G) (p= 0.01) and the presence of preoperative comorbidities (CMB) (p= 0.02). By multivariate regression analysis, the following regression model was obtained: Outcome = PC*0.45 −G*9 + CMB*8 + 62.

This model exhibited positive correlation (R2=.25) when compared to a separate cohort of 27 patients undergoing THA not included in the original equation derivation.

Our multivariate regression analysis has yielded statistical, multivariate confirmation or non-confirmation of common, predictive THA factors that have previously been reported in the literature. This study provides a concrete, statistically significant measure indicating that preoperative WOMAC PC score, gender, and the presence of preoperative comorbidities are predictive factors for short term primary THA outcome. Finally, our multivariate regression equation can be used to predict the general short term patient outcome following primary THA.


Barry J. Waldman

We performed 112 primary total knee replacements in patients under the age of 50, using a unique implant designed to pivot laterally during range of motion.

This design more closely approximates the motion of an ACL deficient knee and controls for the anterior translation typical of more traditional designs. Patients were followed prospectively for a minimum of 3 years (range, 36 to 54 months) All patients were rated both clinically and radiographically using Knee Society Scores, SF-36 and standard radiographic instruments. Patients also completed a validated questionnaire that examined activity level, functional outcomes and ability to return to sports. Patients were compared to case matched historical controls that received a traditional, medially pivoting or flat on flat knee design.

The senior author performed all procedures using a minimally invasive technique with preservation of the quad tendon and accomplished without lateral release. Inclusion criteria were patients under 50 with documented, tricompartmental osteoarthritis. All patients received the same posterior cruciate retaining, laterally pivoting knee prosthesis. Implanted with cement. All patients had resurfacing of the patella performed. The patients were compared to a case matched group of patients that received a modern medially pivoting knee replacement design.

At last follow up, the mean Knee Society functional score was 94. There were no infections, fractures or other major complications in this group. Patients reported quicker recovery of quadriceps function, return to walking without assistance and quicker return to vigorous sports such as tennis. Functional outcomes were statistically improved over historical controls. There was no loss of radiographic alignment or increased signs of loosening compared with historical standards on the most recent radiographs.

Total knee arthroplasty using a ACL substituting device was functionally superior to medially pivoting devices in this patient population. Patients reported better quadriceps dependent activities such as stair climbing and getting up from a chair. They were able to participate in more active sports without late signs of loosening or osteolysis. The authors can recommend this design in younger patients interested in vigorous activity, but full evaluation of this prosthesis will require longer-term results.


S. M. Zingde F. Leszko R. D. Komistek M. R. Mahfouz R. C. Wasielewski J. A. Argenson

Previously, Komistek et al have demonstrated anomalous behaviours in total joints such as separation (sliding) in THAs and condylar lift-off in TKAs. These cases result in reduced contact area, increased contact pressure, polyethylene wear and could induce prosthetic loosening and joint instability.

However, here is no known research done on correlating kinematic conditions with acoustic data for the tibio-femoral joint interface. This study deals with the development of a new method to diagnose such conditions using sound and frequency data. The objective of this study was to determine and compare the in vivo, 3D kinematics and sound for younger subjects with a normal knee, to those of older subjects, with an unimplanted and implanted knee joint.

Ten older subjects having a Hi-Flex PS MB TKA and a contralateral non implanted knee and five younger subjects (with a normal knee) were analysed under in vivo, weight-bearing conditions using video fluoroscopy and a sound sensor while performing four different activities.

deep knee bend to maximum flexion

gait

stair climb and

chair rise and sit.

Three piezoelectric triaxial accelerometers were attached to the femoral epicondyle, tibial tuberocity and the patella respectively. The sensor detects frequencies that are propagated through the tibio-femoral interaction. The signal from the accelerometers was then transferred to a signal conditioner for signal amplification. A data acquisition system was then connected to receive the amplified signal from the signal conditioner and transfer it to a laptop for storage. A sampling rate of 10500Hz was used and frequencies upto 5000Hz were recorded. The signal was then converted to audible sound. Also, 3D tibio-femoral kinematics of the knee was determined, for the four activities with the help of a previously published 2D-to-3D registration technique. The fluoroscopy video and the sensor measurements were synchronized, analysed and compared from full extension to maximum knee flexion for DKB, one full cycle of gait, one complete step on stair climb and from sit-to-stand positions in chair rise.

On average the subjects achieved more flexion with their TKA than with their contralateral knee and consequently experienced significantly higher ROM for their implanted knee. However, both of these groups achieved lower ROM than the normal knees. Significant differences were seen in the AP position of the tibiofemoral contact point. The contact point of the medial condyle for the TKA knee was significantly more posterior at 0° and 30° and remained more posterior than the same condyle of the contralateral throughout flexion. Posterior femoral rollback was seen in all groups, with the normal knee achieving significantly higher posterior femoral rollback when compared to the contralateral and TKA knees. Audible signals were observed for all three groups of knees. The frequency analysis revealed that specific frequencies for all groups were within the same range, but the most dominant frequency for each varied. This may be related to the variable interaction surfaces leading to different dominant frequencies which were excited at magnitudes related to the type and condition of material being impacted (polyethylene/meniscus).

This was the first study to correlate in vivo kinematics to in vivo sounds in the knee. The sounds that were detected correlated well to in vivo motions, especially abnormal kinematic patterns. The ultimate aim of this study is to create a stand alone tool (based only on sound data) that could be used as a diagnostic tool to determine total joint conditions and reduce the dependence on radiation techniques.


C. Clary S. Pal P. Rullkoetter

Musculoskeletal models of the lower limb lend insight into muscle forces and joint mechanics during dynamic activities. However, traditional musculoskeletal modeling is based on rigid body assumptions, and frequently represents the knee as a hinge joint, neglecting the complex interactions between the patella, femur, and tibia. Implementation of the musculoskeletal modeling framework in an explicit finite element environment allows joint contact to be easily incorporated, as well as representation of any structure as rigid or fully deformable in order to evaluate, for example, implant stresses or bone strain. Prediction of these values is particularly valuable when evaluating implant mechanics after total knee replacement.

A finite element, musculoskeletal model of an implanted right lower limb was constructed, including thirteen muscles crossing the knee joint. A Hill-type muscle model was developed to allow muscle activation within the explicit FE framework. Muscle forces were predicted by optimization of muscle activation patterns during flexion-extension and chair-rise activities. The effect of muscle path representation was investigated using two approaches: lines of action directly between the origin and insertion sites of the muscles, and lines of action along the centroid of the muscle bodies. Incorporating anatomic muscle paths into the model reduced the predicted peak quadriceps force during the chair-rise activity by 46%, and reduced the peak tibio-femoral contact pressure by 14%. In addition, bone strain was predicted during the activity for the implanted patella, and showed peak bone strain at the edge of the implant near the inferior pole.

The muscle-activated models demonstrated the advantages of an explicit finite element framework, and allow rapid, rigid body simulation in addition to the full contact, deformable analyses when greater resolution is required.


Bernard N. Stulberg David J. Covall Jay D. Mabrey Burstein Albert H. PhD Laurent D. Angibaud Keisha Smith Jayson D. Zadzilka

We introduce a new technique called the “Posterior Cruciate Referencing Technique” (PCRT), a specific combination of surgical technique, devices and instrumentation. Careful anatomic preservation of the posterior cruciate ligament (PCL) based upon a specific reference point off the tibia allows for use of sloped tibial components to achieve consistent functional behavior of the PCL. We discuss the preclinical design and development leading to availability of this device, and subsequent early clinical experience with this approach.

Posterior cruciate ligament (PCL) retention in total knee arthroplasty (CR-TKA) has been a feature of certain styles of TKA since the inception of predictable TKA in the early 1970s. It has been adapted and promoted as advantageous for a number of real and theoretical benefits. In reality, however, PCL retention has proven inconsistent when applied across a broad range of surgical environments. A number of adaptations in surgical technique, device modification and instrumentation have been developed to try to improve the predictability of the surgical intervention and subsequent postoperative performance. It is our belief that currently recommended surgical techniques can lead to inconsistencies in surgical judgment and consequently performance of CR devices because they inadvertently compromise the anatomy and hence functional performance of the PCL. A study by Shannon et al showed that, during CR-TKA, the PCL was either partially or completely removed as a result of the tibial cut in two out of three cases [1]. Unlike the long held and validated approach of ligament releases for fixed New Technique for Functional Posterior Cruciate Retention in TKA varus and valgus deformity that, along with alignment, allow successful long 45 term outcomes, ligament release of the PCL to balance the knee in flexion, whether by bone cuts or physical release, may compromise its overall function and explain kinematic differences in expected versus observed performance. Our hypothesis is that devices, surgical techniques and instruments designed around anatomical and functional preservation of the PCL would promote a reproducible surgical approach and consistent clinical performance of a CR-TKA. This manuscript provides the rationale for development of a new technique called the “Posterior Cruciate Referencing Technique” (PCRT), a combination of technique, instruments and devices specifically designed to preserve the PCL anatomy and take advantage of the functional performance of the PCL. We discuss the anatomical, radiographic, kinematic and mechanical testing approach that suggests that this is a safe and effective approach for primary CR-TKA.

Conclusion: This manuscript presents a body of work that elucidates specific issues of implant design and technical implantation that may have led to inadvertent compromise of function of the PCL during CR-TKA. We believe that such compromises may explain the inconsistent kinematic behavior of these devices in the hands of surgeons who use them, and may result in clinical outcomes that were unintended. We have provided the rationale for a new technique of implantation the Posterior-Cruciate Referencing Technique (PCRT) -which mates specific referencing approaches of the PCL and tibial resection, with implants, to address PCL functional New Technique for Functional Posterior Cruciate Retention in TKA behavior. We have provided laboratory, pre-clinical and early clinical evaluations that suggest that this will prove a safe and effective approach to CR-TKA.


CF de Biase A Vitullo G Di Giorgio F d’Imperio A Carfagni

Purpose: The purpose of this retrospective studies is to evaluate the real effectiveness, with clinical and radiologic evalutation, of the eccentric glenosphere and also how a correct position can prevent the scapular notching.

Material and Methods: We inplanted in 18 patients, with eccentric arthopaty, a 36 mm eccentric glenoshere.24 months’ clinical and radiographic follow up. All patient were assessed preoperatively and postoperatively with the Constant Score. In the post-operative radiographic control we have taken in consideration: the presence of notching, psna (prosthesis-scapular neck angle), pgrd (peg glenoid distance), glenoid inclination, craniocaudal position of the glenosphere in relation to the glenoid.

Results: The ROM increased in all level. All of the 18 shoulder had no notching. The craniocaudal position of the glenosphere in relation to the glenoid is 4,3 mm. The PSNA was 92° and the PGRD was 21.2.

Conclusion: The inferior scapular notching is the most important complicance of reverse prosthesis. The results of our study indicate that : the correct positioning of the metal back, at the center of the glenoid (better biomechanics stability), without overhang and with eccentric glenosphere, permits to lower the center of rotation of 4 mm avoiding the notch and so increasing the adduction and abduction range of motion.


Yossef C Blum Amar S Ranawat Chitranjan S Ranawat

Introduction: In 1979, our senior author described his technique for correcting a flexion contracture during total knee arthroplasty (TKA) by additional resection of the distal femur and posterior capsular release; he also described his method of correction of a varus deformity by raising a subperiosteal sleeve from the proximal tibia. Due to concerns related to elevation of the joint line as well as flexion/extension gap asymmetry and instability, our technique has evolved into a methodical soft tissue release at the level of the joint line. Our hypothesis is that this technique effectively corrects both deformities, while reducing the complications related to the more traditional techniques.

The purpose of this study is to describe this technique and assess its effectiveness in a series of 31 consecutive patients.

Technique: Highlights of this technique are as follows:

This method involves osseous resections of 10mm from the level of the uninvolved surfaces of the femur and tibia in order to restore the mechanical axis.

A transverse release of the contracted posterior capsule is performed with electrocautery at the level of the tibial resection from the posterior margin of the superficial medial collateral ligament (MCL) to the posterolateral corner of the tibia.

A controlled lengthening of the superficial MCL is achieved by pie-crusting.

Results: Over a 12 month span, we have corrected these biplanar deformities in 31 knees without residual instability. There were no residual flexion contractures greater than 5 degrees. The maximum varus corrected was 30 degrees, and the maximum flexion contracture corrected was 20 degrees. The mean coronal plane correction was to 5.5 degrees of valgus (range: 1 to 9 degrees).

Discussion: In a series of 31 consecutive patients, this technique was effective in correcting both deformities. We achieved a mean range of motion of 115 degrees, while avoiding elevation of the joint line or instability. Theoretically, this method should result in more optimal knee mechanics than traditional methods. While we are reporting good early results, a prospective, randomized controlled study is needed to better evaluate this technique.


Dan J. Berry

It has become a platitude that total knee arthroplasty (TKA) is an excellent operation, provides good pain relief, and over 90% survivorship at 20 years in many series. While all these points are true, total knee arthroplasty as practiced currently still will not meet the demands of many patients who will desire the procedure in the next ten years. The reasons for this include changing demographics of TKA and the changing demands of TKA candidates. TKA is being performed more frequently in patients under 60, in fact this is the fastest growing group of patients by percent growth. We performed a population-based study of trends utilization of TKA and found increasing TKA utilization in all age groups over time but the greatest increase by percent in the youngest patients. Furthermore, younger patients now no longer tend to be lowactivity patients with inflammatory disease. The percentage of patients with primary osteoarthritis and post traumatic arthritis has increased dramatically. Long-term studies of TKA have shown such durability in part because many of the younger patients were Charnley Class C patients, and because historically most TKA patients were older with an average age of most early series of around 69 years. This means there were far fewer young patients in early TKA series than in early THA series. This is important because material failures occur predominantly in younger patients and durability is a greater concern in younger patients, so one may predict that this younger, more active group will not enjoy the same level of TKA durability reported in the literature unless technology improves.

Total knee arthroplasty patients are more active than one might predict. In a study of 1200 patients surveyed at five years the average UCLA score was 7 out of 10. Younger patients achieved a higher activity level but were in general less satisfied with activity provided by TKA than older patients. This implies there is a need for better designs and surgery to facilitate more normal kinematics, more flexion, and more quadriceps strength. A study by Weiss and Noble (CORR 2002) identified specific activities associated with limitations after knee arthroplasty.

Furthermore, a study by Bourne and associates demonstrated lower satisfaction scores after total knee arthroplasty than hip arthroplasty. Finally, in our study of activity levels after knee arthroplasty we found that 16% of current patients participate in heavy labor or sports not recommended by Knee Society guidelines. These patients tend to be younger and predominantly male. This implies there is a subset of the population already doing things that will challenge the current generation of total knee arthroplasty and more patients want to do these activities and already do so. Therefore, there is a need for improved implant durability and improved knee function after knee arthroplasty. This suggests the methods of fixation may need to evolve to accommodate higher demands, and bearing surfaces definitely need to evolve to accommodate higher demands. Finally, more sophisticated implant kinematics to avoid or compensate for anterior cruciate ligament and posterior collateral ligament deficiency and more sophisticated surgery to optimize implant alignment and soft tissue balancing in the individual patient will be necessary to achieve more normal patient knee kinematic stability, strength and “feel”. Finally, we will need better and more sensitive scoring systems to detect improvements in future TKA surgery and design in the future.


J D Blaha D K DeBoer C L Barnes R M Obert P M Stemniski M E Carroll

Introduction: An open-chain model was used to investigate the kinematics during isometric extension between normal knees and knees replaced with a tricompartmental prosthesis.

Methods: Ten cadaver legs were skeletonized while preserving the knee joint capsule, quadriceps and hamstring tendons. CT scans of the extremity were converted to CAD models that precisely related the bone surfaces to radio-opaque motion analysis markers. The limbs were mounted in a custom open-chain extremity rig [1]. Tibial motion was produced by a linear actuator attached to the quadriceps tendon in the direction of the vector addition of the absent quadriceps muscles. Tendon force was measured with an in-line force transducer and recorded at 300 Hz during the motion. Three-dimensional kinematic data of the isometric extension motion of the knee were recorded at 30 Hz using a motion capture camera system and combined with CAD models of the extremity to evaluate joint kinematics through virtual animations, contact points, and kinematic profiles. After collecting data on normal knee kinematics, each specimen underwent total knee replacement with commercially available implants. Anatomic and implant coordinates were registered to the motion capture data and the captured motion was imposed on the virtual model. The femoral anatomic axis was defined as a line from the center of the femoral head to the posterior cruciate ligament (PCL) femoral insertion point [2]. The tibial anatomic axis was defined as a line from the center of the line connecting the proximal tibial prominences to the center of the distal tibial articular surface [2]. The femoral internal/external (IE) rotation reference was a line connecting the peaks of the medial and lateral epicondyles [2]. The tibial IE rotation reference was a line defined by the anterior boundaries of the articular surfaces [3]. IE rotation angle was defined as the angle between these two reference lines, on a plane perpendicular to the tibial axis. Contact points between the femur and tibia, or corresponding components for the implanted knee, were determined in 30° increments between full extension and 120° flexion [4]. Animations of the virtual CAD models were created for visualization of the motion data.

Results: Tibio-femoral contact points for the normal knee indicate stable behavior on the medial compartment and progressive posterior motion of contact on the lateral side with increasing flexion. The normal knees demonstrated anterior contact on both the medial and lateral sides at full extension (0°). Within the first 30° of flexion, the contact point moves backwards on both medial and lateral sides of the joint, but markedly more so on the lateral. From then on, the contact point stays stable in the mid portion of the medial tibial plateau and more posterior on the lateral demonstrating medial pivoting kinematics. The replaced knee does not demonstrate the “screw-home” from 0°–30° but does demonstrate a stable medial contact point in the mid portion of the tibial plateau and gradual posterior movement of the contact point on the lateral side through 120°, indicating medial pivoting kinematics similar to the normal. These patterns were virtually identical across all specimens. Contact point translation data after knee replacement was consistent with the behavior of the normal knee. The anterior-posterior translation of each condyle for each specimen was normalized and averaged. The replaced knee demonstrated equal or smaller displacement values in all but one category (lateral deep flexion) and maintained similar profiles in all flexion ranges. These results indicate that the replaced knee is stable medially throughout the range of motion wth controlled lateral translation. The contact point AP position was compared at discreet flexion angles between normal and replaced knees. On the medial side, from 0°–110°, there was no statistical significant difference between the two cases with the p-values ranging from 0.45 to 0.79. However at 115° of flexion, the p-value was 0.04 indicating a statistical difference between the normal and replaced knees. The lateral condylar comparison yielded three flexion angles with a statistical difference, 60°, 105°, and 115° with pvalue of 0.05, 0.03, and 0.01 respectively. The mobility of the normal lateral compartment and the more constrained motion path of the replaced component are a factor of these differences.

Kinematic profiles of internal-external rotation and adduction-abduction for normal knees were consistent in shape among all specimens. Replaced knee kinematic profiles varied from normal but were consistent across specimens. The peak quadriceps tendon load for all specimens occurred at 65° with a decrease as the leg progressed to full extension. Tendon load of the implanted knee reached a maximum at 65° which then remained nearly constant through 15°. Tendon loads at 65° are within 10% of the normal knee loads (−4.5% ± 5.6) with two of the three specimens having greater than 10% decreases in tendon load.

Discussion and Conclusion: The normal knee kinematics appear to be driven by the bone geometry and the physical constraints of the soft tissues. The replaced knee kinematics are dependent mostly on the designed geometry of the implants since both cruciate ligaments and cartilage are absent from these trials. The total knee prosthesis implanted was designed as a ballin-socket on the medial side with a “ball-in-arcuate groove” on the lateral side. This design was intended to mimic the stable medial side of the normal knee while allowing the lateral side to rotate around it. In this open chain model, both normal and replaced knees indicate a stable medial side and free motion on the lateral side, demonstrating medial pivoting kinematics. The replaced knees also closely approximate the surface kinematics of the normal knees. Variation in kinematic profiles between the normal and replaced knees are partially attributed to surgical alignment correction. The quadriceps load necessary to move the knee at the same rate through the same range of motion were similar for the replaced knee compared to the normal knee exceeding the normal load by a maximum of 2%.


J.Y. Jenny F.P. Firmbach

Navigation systems have proved to improve the accuracy of the bone resection during total knee replacement (TKR). They might also be helpful to assess intra-operatively the knee kinematics before and after prosthesis implantation.

We are using the OrthoPilot® system (Aesculap, Tuttlingen, FRG) on a routine basis for TKR. The current standard version of the software helps the surgeon orienting the bone resections and allows measuring the ligamentous balancing. This version was modified to allow a continuous tracking of the 3D tibio-femoral movement during passive knee flexion and extension. The kinematics was assessed by measuring the tibial movement in these three planes with the femur as reference.

For the purpose of the study, following data were registered before and after implanting the prosthesis: flexion-extension angle, varus-valgus angle, rotational angle, antero-posterior translation. Additionally, the gap between the contact point of the femoral component and the corresponding point of the tibial resection was measured after prosthesis implantation. Two successive registrations were performed by each of the 100 patients of the study before and after prosthesis implantation. The pre-and post-implantation kinematic curves were respectively compared by each patient to assess reproducibility. The pre-and postimplantation kinematic curves were compared by each patient to assess the modification due to prosthesis implantation. The results were compared to the current available literature.

The kinematic curves were plotted from maximal extension to maximal flexion. The observed 3D kinematics seem to be in agreement with the current literature in both in-vitro and in-vivo studies. We could observe the tibial internal rotation and the femoral roll-back during flexion. Some patients experienced paradoxical movement, both before and after implantation. However the post-implantation kinematics was generally closer to the expected one than the pre-implantation kinematics.

The software has definitely the potential to assess the intra-operative knee kinematics during various surgical procedures. It might help to try several solutions (orientation of the resections, implant combination or design, ligamentous balancing… ) before final implantation, in order to choose the best individual compromise. The actual relevance of such a study remains to be defined. It might be interesting to compare these data with in-vivo kinematic studies by the same patients.


N.A. Shah N.B. Giripunje

Obesity has been associated with degenerative osteoarthritis of knee joint The over all incidence of osteoarthritis of the knee is also more in patients with obesity. Increasing obesity leads to faster progression of OA, which is due to increased joint load. Body mass index (BMI), dividing an individual’s weight (in kg) by his or her height (in square meters). BMI: Normal = 18.5 to 24.9, Overweight BMI −25–29.9 Obese=30 to 39.9, Morbidly Obese BMI 40 or Greater. Recent article focused on the thigh girth of obese patients and opined that if thigh girth > 55cms, subvastus approach should not be utilized, as it is difficult to evert the patella. We believed that obesity should not really cause a problem for the patients undergoing a TKA with the mini subvastus approach as the anatomy of the quadriceps in the obese and the non-obese patient population is the same. We decided to evert the patella only after osteotomy of tibia and the femur.

All patients who underwent primary total knee arthroplasty with minisubvastus approach between January 2006 to July 2007 and who were obese (BMI> 30) were included in our study. Out of 425 primary Total knee arthroplasty were performed during this period. Out of these, there were total 97 obese patients with 109 knees which form the part of the study.

There were 81 females and 16 males and 12 patients had staged bilateral knee arthroplasty. The weight varied from 63 to 125 kgs. 91 patients had varus deformity of < 15 degree, 15 patients had varus deformity of > 15 degree, 3 patients had valgus deformity. The thigh girth in obese group (BMI: 30–40) ranged from 45 to 58 cms with average of 50.17. The thigh girth in morbidly obese (BMI > 40) group ranged between 55 to 67 with average of 61.01 cms.

Mini-subvastus approach provided satisfactory exposure in all knees that were operated. In no case was this approach abandoned.

The average surgical time was 90 minutes with range. The average blood loss was 400 cc. The patellar tracking was immaculate in every case and in fact it was difficult to displace patella laterally after 30 degrees of knee flexion. Our 89 patients had flexion of > 120 0,and 20 patients had flexion of > 90 but < 120. The knee society score improved from average 42 (range 17–62) preoperatively to 89 (range 72–95) post operatively. The Knee Society functional score improved from 48 (range 15–60) pre operatively to 65 (range 50–80) post operatively.

Mini subvastus approach offers adequate intraoperative exposure even in obese and morbidly obese patients. It did not result in increased complications in our hands even in morbidly obese patients with higher thigh girth. It is extremely patient friendly and its wider use is recommended.


A. Matsuo S. Jingushi Y. Nakashima T. Yamamoto T. Mawatari Y. Noguchi T. Shuto Y. Iwamoto

Transposition osteotomy of the acetabulum (TOA) was the first periacetabular osteotomy for the osteoarthritis hips due to acetabular dysplasia, in which the acetabulum was transposed with articular cartilage. TOA improves coverage of the femoral head to restore congruity and stability, and also prevent further osteoarthritis deterioration and induce regeneration of the joint. Many good clinical outcomes have been reported for such periacetabular osteotomies for osteoarthritis of the hips at an early stage. In contrast, the clinical outcome is controversial for those hips at an advanced stage, in which the joint space has partly disappeared. The purpose of this study was to investigate whether TOA is an appropriate option for treatment of osteoarthritis of the hips at the advanced stage by comparing with matched control hips at the early stage.

Between 1998 and 2001, TOA was performed in 104 hips of 98 patients.

Sixteen of 17 hips (94%) with osteoarthritis at the advanced stage were examined and compared with 37 matched control hips at the early stage. The mean age at the operation was 48(38–56) and the mean follow-up period was 88 (65–107) months. TOA corrected the acetabular dysplasia and significantly improved containment of the femoral head.

No hips had secondary operations including THA. Clinical scores were also significantly improved in both of the groups. In the advanced osteoarthritis cases, there was a tendency for abduction congruity before transposition osteotomy of the acetabulum to reflect the clinical outcome.

TOA is a promising treatment option for the advanced osteoarthritis of the hips as well as for those patients at the early stage when preoperative radiographs show good congruity or containment of the joint.


S Takai

Soft tissue balancing remains the most subjective and most artistic of current techniques in total knee arthroplasty. It is well known that it is more difficult to achieve posterior roll-back with CR than with PS. Extension and flexion gaps on the sagittal plane, and medial and lateral gaps on the coronal plane have to be well balanced. However, it is very difficult to match these four. Biomechanical properties of the soft tissue were obtained during the surgery, using the specially designed system. The system consists of two electric load cells in the tensioning device, digital output indicators, and an XY plotter. Load displacement curves were obtained in extension and in flexion. Interestingly, the stiffness of curves obtained from the lateral in flexion is 1/3 lower than the other three. However, it is very questionable whether we can adjust these materials precisely and constantly or not.

To achieve posterior roll-back and deep knee flexion, ligament balancing is more important in cruciate retaining TKA than in PS Knee. Posterior impingement and anterior lift-off are often seen during surgery. That means “too tight in flexion”. First of all, elementary correction of the coronal deformity is performed by appropriate removal of osteophytes and soft tissue release. A pre-cut is made 2–3 mm distal to the conventional cutting line at the distal femoral end. Femoral component size is determined in accordance with the antero-posterior dimension. Posterior femoral condylar resection is performed. A load is applied in flexion to measure flexion gap. The extension gap is then measured in extension with the same load as that which was applied in flexion. Additional bone re-cut of the femoral distal end is performed.

The technique is very similar to the classic flexion-extension gap balance technique.

However, the most different point I would like to emphasize is that an accurate and constant load is applied to make both the flexion and extension gaps equal. There is no need to release the PCL using this technique. Therefore, I would like to name this technique “Load dependent gap technique” to emphasize that an accurate and constant load can be clearly applied to equalize the gaps.

In future, using this technique, it could be possible to know what percentage of the load applied in extension should be appropriate in flexion when the two gaps are equalized in TKA.


D.R. Walker H. Cleppe D.T. Sahajpal T.W. Wright S.A. Banks

Reverse shoulder arthroplasty (RSA) is increasingly utilized to restore shoulder function in patients with osteoarthritis and rotator cuff deficiency. There is currently little known about shoulder function after RSA or if differences in surgical technique or implant design affect shoulder performance. The purpose of this study was to quantify scapulohumeral rhythm in patients with RSA during loaded and unloaded shoulder abduction.

Eleven patients with RSA performed shoulder abduction (elevation and lowering) with and without a handheld 3kg weight during fluoroscopic imaging. Three RSA designs were included. We used model-image registration techniques to determine the 3D position and orientation of the implants. Cubic curves were fit to the humeral elevation as a function of the scapular elevation over the entire motion. The slope of this curve was used to determine the scapulohumeral rhythm (SHR).

For abduction above 40°, shoulders with RSA exhibited an average SHR of 1.5:1.

There was no significant difference in SHR between shoulder abduction with and without 3kg handheld weights (1.6±0.2 unweighted vs. 1.4±0.1 weighted), nor was there a significant difference between elevation and lowering. SHR was highly variable for abduction less than 40°, with SHR ranging from a low of 1 to greater than 10. For these very small groups, there was no apparent pattern of differences between implant designs having differing degrees of lateral offset.

At arm elevation angles less than 40°, SHR in RSA shoulders is highly variable and the mean SHR (2–5) with RSA appears higher than SHR in normal shoulders (2–3).

At higher elevation angles, SHR in shoulders with RSA (1.5–1.8) is much more consistent and appears lower than SHR in normal shoulders (2–4). With the small subject cohort, it was not possible to demonstrate differences between subjects with different implant designs. Ongoing analysis of reverse shoulder function with larger cohort sizes will allow us to refine our observations and determine if there are differences in shoulder function due to implant design, preoperative condition and rehabilitation protocols.


T.E. Lassiter R.A. Schroeder D.L. McDonagh M.P. Bolognesi V.K. Sarin T.G. Monk

Elderly patients are at risk of developing cardiopulmonary and cognitive impairment following major orthopaedic surgery. One of the mechanisms believed to be responsible for such complications after total knee arthroplasty (TKA) is the release of embolic debris that may travel from the surgical site, through the lungs, and into the brain following tourniquet release. Removal of fat globules and marrow particulates from bone surfaces prior to pressurization and cementation of prosthetic components may reduce the number and size of embolic particles. We conducted a prospective, randomized clinical trial to compare the effect of carbon dioxide (CO2) gas versus saline lavage on the number and size of embolic particles observed during cemented TKA.

Twenty patients undergoing elective TKA were randomly assigned to one of two groups. In group A, standard high-pressure pulsatile saline lavage was used to clean the resected bone surfaces. In group B, the femoral canal was cleaned using CO2 lavage techniques and the resected bone surfaces were cleaned with a manual saline wash followed by CO2 lavage. All patients received the same TKA implant design. The presence of embolic particles in the heart and brain was intraoperatively monitored using transesophageal echocardiography (TEE) and transcranial Doppler (TCD) techniques, respectively. For each patient, TEE images were analyzed at tourniquet release and during the final range of motion (ROM) assessment prior to wound closure using the following five point cardiac echogenic scoring system: Grade 0: no emboli; Grade I: a few fine emboli; Grade II: a cascade of many fine emboli; Grade III: a cascade of fine emboli mixed with at least one embolus > 1 cm in diameter; and Grade IV: large embolic masses > 3 cm in diameter. The highest grade observed during either tourniquet release or ROM assessment was assigned to each patient. Cardiac emboli were then categorized according to embolic grade as follows: Grade 0 or I = Low; Grade II, III, or IV = High. For analysis of cerebral emboli, the total number of positive counts measured using TCD was recorded for each patient. TEE data were available for nine patients in group A and eight patients in group B. Comparative TCD data were available for seven patients in group A and six patients in group B. Fischer’s Exact Test was used to check for differences between groups.

For cardiac emboli, nine of nine (100%) patients in group A were in the High category based on their TEE grade, with eight patients being Grade II and one Grade III. In contrast, three of eight (37.5%) patients in group B were in the Low category, leaving only five (62.5%) in the High category (p = 0.08). All five group B patients in the High category were Grade II. No patients in group A had cerebral emboli detected using TCD. In group B, three of six patients had one cerebral embolus and the remaining three had none. Three patients in group B were excluded from the comparative TCD analysis due to the presence of a patent foramen ovale (PFO). These three patients with a PFO had one, three, and four cerebral emboli, respectively. No patients in group A had a PFO.

This study examines the effect of pulsatile saline versus CO2 gas lavage on intraoperative embolic events during TKA. Thirty-seven percent of patients in the CO2 lavage group had a Low cardiac echogenic score compared with 0% of patients in the standard pulsatile saline lavage group. A single cerebral embolus was detected in three of six patients in the CO2 lavage group compared with none in the seven patients in the standard pulsatile saline lavage group. Compared to published studies on cerebral emboli in TKA, the overall incidence of cerebral emboli in the current study was very low across both groups. The results of this study suggest that CO2 gas, as compared to pulsatile saline, lavage reduces the number of intraoperative cardiac emboli during total knee arthroplasty.


H. O. Amadi A. L. Wallace U. N. Hansen A. M. J. Bull

Introduction: Classical studies have defined axes from prominent scapular landmarks that have been used to synthesise many applications. The morphology of the scapula is however known to be highly variable between individuals1,2,3. This introduces significant variability on the use of these classical axes for various clinical applications. Also, some of the literatureapplied landmarks were highly dependant on the presence of pathology, thus introducing more variability in the products they parented. This limits accuracy in inter-subject comparisons from such applications. Therefore there is a need to identify and define pathology-insensitive anatomical landmarks that are less variable between individuals than the variability of the overall scapular shape. The aim of this study was to define more scapular axes from clearly identifiable landmarks, analysing these and other classical definitions for the best axis that minimizes variability and is closely related to the scapular clinical frame of reference.

Materials and Method: Fourteen different axes of new and classical definitions from clearly identifiable landmarks were quantified by applying medical images of 21 scapulae. The orientations of the quantified axes were calculated. The plane of the blade of the scapula was defined, bounded by the angulus inferior4, the spine/medial border intersection5 and the most inferolateral point of the infra-glenoid tubercle. This was applied to grade the alienation of the quantified axes from the scapular blade. The angular relationships between individual axes of a spcapula were quantified, averaged over the 21 specimens and their standard deviations (SD) applied to grade the sensitivity of each axis to interscapular variations in the others. The volume of data required to define an axis (VDA) was noted for its dependency on pathology. These three criteria were weighted according to relative importance such that

axes bearing 10° or more from the blade deviated significantly and were eliminated;

insensitivity to scapular morphological variations based on the smallest SD and axes applicability in pathology based on VDA of the remaining axes were graded for the final result.

Results: A least square line through the centre of the spine root was the most optimal medio-lateral axis. The normal to the plane formed by the spine root line and a least square line through the centre of the lateral border ridge was the most optimal antero-posterior axis.

Conclusion: These body-fixed axes are closely aligned to the cardinal planes6 in the anatomical position and thus are clinically applicable, specimen invariant axes that can be used in generalised and patient-specific kinematics modelling.


PJC Heesterbeek NLW Keijsers N Verdonschot AB Wymenga

Instability is a major cause for revision surgery in total knee replacement (TKR). With a balanced gap technique, the ligaments are theoretically balanced. However, there is concern that ligament releases needed to align the leg may cause instability. Furthermore, no information is available about the relationship between the amount of varus-valgus laxity directly after implantation and at a later postoperative interval. This prospective clinical study investigated whether ligament releases necessary during total knee replacement (TKR) led to a higher varus-valgus laxity during peroperative examination and after 6 months.

In this prospective cohort study, in 49 patients a primary TKR was implanted using a balanced gap technique. Varus and valgus laxity of the knee was assessed in extension and flexion (70 degrees) per-operative (before and after implant) with a navigation system and post-operative with standardised stress radiographs (both methods 15 Nm stress applied).

Knees were catalogued according to ligament releases performed during surgery: no releases, lateral releases, medial releases with posteromedial condyle (PMC), and medial releases with superficial medial collateral ligament (SMCL). ANOVA was used to test between release groups.

At surgery, before and after implantation of the prosthesis, there was no difference in varus or valgus laxity in extension and flexion between knees that did not need a ligament release (n=22), knees with lateral release (n=5), knees with medial SMCL releases (n=15) and knees with medial PMC releases (n=7). Six months after TKR, varus or valgus laxity in extension and flexion was not significantly different between the release categories.

In conclusion, ligament releases of the SMCL, PMC, and lateral structures performed during a balanced gap technique in TKR do not lead to an increased varus-valgus laxity in extension and flexion at 6 months after surgery. Therefore, routine releases of these structures to achieve neutral leg alignment can safely be performed without causing increased varus-valgus laxity. The results of this study suggest that the reported high incidence of revisions for ligament instability after TKR is not likely to be caused by routine ligament releases when a balanced gap technique is used. Apparently, there is not a ligament instability problem as long as the gaps are properly filled with prosthesis components. We believe that the conclusion of this study would also be valid when bone referenced techniques are applied instead of tensors, as long as the gaps created are balanced.


P.K. Puthumanapully M. Browne

Uncemented hip implants commonly have porous coated surfaces that enhance the mechanical interlock with bone, encourage bone ingrowth and promote the formation of a stable interface between prosthesis and bone. However, the presence of tissue, either fibrous or with parts of osseous tissue, at the interface between the implant and the bone has been commonly observed after a few years in vivo. The exact mechanisms that govern the type of tissues formed at the interface are not fully understood and several theories have been proposed. This study aims to employ finite element analysis (FEA) to simulate tissue formation and differentiation around the AML (DePuy, Warsaw, USA) femoral implant by employing a tissue differentiation algorithm based on a mechanoregulatory hypothesis of fracture healing.

FE models of the femur were generated using computer tomography (CT) scans. The AML prosthesis was then implanted into the bone and a granulation tissue layer of 0.75mm was created around the implant. The mechanoregulatory hypothesis of Carter et al (J.Orthop, 1988) originally developed to explain fracture healing was used with selected modifications, most notably the addition of a quantitative module to the otherwise qualitative algorithm. The tendency of ossification in the original hypothesis was modified to simulate tissue differentiation to bone, cartilage or fibrous tissue. Normal walking and stair climbing loads were used for a specified number of cycles reflecting typical patient activity post surgery.

The transformation of granulation tissue to one of the three simulated tissue types was evident as the iterations progressed. The majority of the tissue type formed initially was cartilage and bone (~40% each), and occupied the mid to distal regions of the implant respectively. After tissue stabilisation, the prominent tissue type was bone (65%), occupying most of the mid-distal regions with a significant decline in cartilage tissue formed. This has been shown in clinical retrieval studies with the same implant, where maximum bone ingrowth is in the mid-distal regions of the implant, directly corresponding to the region where there is minimal micromotion. This would be the case with a diaphyseal fixation, which most AML prostheses employ for stability. Fibrous tissue formation was limited to the proximal-medial regions (~10%), with the remainder of the proximal regions filled with cartilage tissue. In addition, predicted bone formation was along the lines of the more stable cartilage tissue as opposed to directly replacing fibrous tissue. The formation of bone would require repeated periods of minimal micromotion and stress at the interface tissue; this was facilitated by the presence of cartilage tissue around the mid regions of the implant. The micromotion and interface stresses in the proximal regions of the implant were too high to encourage bone ingrowth, resulting in the presence of tissue that remained fibrous throughout the process.

The FE model, employing a very simple tissue differentiation hypothesis and algorithm was able to predict the formation of different tissues at the interface. Initial bone formation was rapid, occupying the distal regions of the implant, and then gradually occupying a larger portion of the mid-regions around the implant. The proximal regions were largely occupied by a combination of fibrous and cartilage tissue. Overall, the presence of bone and cartilage tissue accounted for nearly 85% of the tissue formed which would suggest a very stable interface as predicted by the Carter’s hypothesis.


J. Victor F. Hardeman J. Londers E. Witvrouw

Methodology: A retrospective review based on a prospective database was performed on 146 consecutive revision TKA’s. An independent observer measured clinical outcomes using the Knee Society Knee (KS) and Function Score (FS). X-ray evaluation, including rating of radiolucent lines, tibiofemoral and patellofemoral alignment, was carried out by an independent radiologist. ANOVA was used for statistical analysis, with significance set at p≤0.05 (SPSS version 15.0). Post-hoc Bonferroni testing was carried out for single variables including primary cause of failure, age at revision surgery, time span between index operation and revision, type of index operation, partial or total revision and the performance of a tuberosity osteotomy.

Results: 146 files were available in 135 patients. 16 patients deceased (17 knees) during the follow-up period and 2 patients (2 knees) were lost to follow-up. 117 patients (127 knees) were available for evaluation. Age at revision surgery averaged 67.7 years (range 32.3–88.1). Mean follow-up time was 4.5 years (range 1–14). Patients had revision TKA between 51 days and 16.1 years (average 4.7 years) after the index TKA. 54% of the early revisions were due to infection and instability, 55% of late revisions were caused by polyethylene-wear and loosening. The mean postoperative KS was 70.8 with a mean improvement of 43.2 points as compared to pre-operative. The mean postoperative FS was 52.9 with a mean improvement of 25.4 points. Grouping outcomes according to cause of failure of the index TKA gave the following ranking from better to worse, without being significant: wear (n=15; KS 80.8; range 43–99, SD 17.5), loosening (n=44; KS 75.8; range 15–100, SD=21.2), malalignment (n=19; KS 70.0; range 9–95, SD 25.9), instability (n=33; KS 68.2; range 5–100, SD 24.1), others (n=16; KS 66.7; range 10–100, SD 25.9), and infection (n=21; KS 64.2; range 3–100, SD 31.7). Survivorship at 5 years was 90.0% (CI 86.4% –93.6%), at 10 years 84,6% (CI 77.0% –92.3%) and at 14 years 84,6% (CI 37.7% –131.6%). Significant better outcomes were seen with late revisions, index operation being partial knee replacement and older age at revision. More failures (p=0.002) were seen with early revisions. In 32.6% of the patients radiolucent lines of ≥1 mm were observed. Points were granted with the use of a Radiolucency Scoring Scheme. Patients with less than 4 points (n=87, mean KS 71.2) had better outcomes than patients with 4 or more points (n=8, mean KS 56.4). 87% of patients were aligned within 4° of mechanical axis.

Conclusion:

Outcomes of revision TKA are inferior to primary TKA.

Early failures were mainly caused by infection, instability, malalignment.

Grouping revision TKA’s to etiology of failure did not lead to significant differences in outcomes.

Significant better outcomes were reported for late revisions, patients with older age at revision surgery and partial knee replacement.

Survivorship analysis was significally better for late than for early revisions.


RC Wasielewski KC Sheridan RD Komistek

Recent fluoroscopic analyses evaluating the kinematic function of TKAs have demonstrated significant variability among patients with identical implant designs, suggesting surgical technique also influences function. To help explain these kinematic variations, we used intraoperative compartment pressure sensors to assess balancing at trial reduction and ROM then correlated these intraoperative findings with patients’ postoperative kinematics, assessed using video fluoroscopy.

This study involved 16 patients implanted with a posterior cruciate-sacrificing LCS TKA using a balanced gap technique. After releases in extension, the femur was rotated the appropriate amount to create a rectangular flexion gap relative to the cut tibial surface. As the knee was taken through a ROM from 0–120°, the sensors (placed on the tibial insert trial) dynamically measured the magnitude and location of compartment pressures throughout the ROM. Six to nine months postoperatively, all patients performed successive weight-bearing deep knee bends to maximum flexion under fluoroscopic surveillance. Each patient’s femoro-tibial contact positions and liftoff values were compared to their respective intraoperative compartment pressure findings to establish correlations.

Fluoroscopic results correlated closely with intraoperative compartment pressures and balance data. Three of the 16 patients had condylar liftoff: two patients experienced liftoff in flexion and one in extension (medial). The patient who experienced medial liftoff in extension had decreased medial compartment pressure and a slight valgus malalignment (7° of anatomic alignment). Two of the 13 patients without liftoff had abnormal compartment pressures in extension. In both cases, mechanical axis alignment resulted in loading of the lax compartment with weight-bearing. The other 11 patients had normal compartment pressures in extension and no condylar liftoff. One of these patients had slight valgus (7°) and another slight varus malalignment (4°), but both had normal compartment pressures. Despite good compartment balance, average tibiofemoral rotation was inadequate; three of 16 patients experienced opposite axial rotation with flexion. Extensive ligament release did not always result in equal compartment pressure magnitudes and distributions; compartment balance was influenced by the nature of the release.

These data suggest that liftoff may require both a compartment pressure imbalance and abnormal alignment that together exacerbate the laxity with physiologic loading. Previous kinematic studies of LCS knees have shown that the balanced gap technique produces wellbalanced compartment pressures, resulting in TKAs with little lift-off and very good translational and rotational characteristics. Therefore, while a given implant design may have inherent kinematic tendencies, surgical technique may significantly impact kinematic performance. To optimize implant kinematics and subsequent TKA function and longevity, it may be important for surgeons to accurately balance the flexion and extension gaps. Characteristic compartment pressure patterns and distributions for various ligament releases may shed some light on less than optimal rotational kinematic performance.


T. Matsumoto S. Kubo H. Muratsu K. Ishida K. Tei K. Sasaki T. Matsushita M. Kurosaka R. Kuroda

Purpose: A common difficulty with manually-performed total knee arthroplasties (TKAs) is obtaining accurate intra-operative soft tissue balancing, an aspect of this procedure that surgeons traditionally address through their “subjective feel” and experience with an unphysiological joint condition. We have therefore developed a new tensor for TKAs that enables us to assess for soft tissue balancing throughout the range of motion about the knee with a reduced patello-femoral (PF) joint and femoral component in place. This tensor permits us to intra-operatively reproduce the post-operative alignment of the PF and tibio-femoral joints. The main purpose of this study is to compare ligament balance in cruciate-retaining (CR) and posterior-stabilized (PS) TKAs.

Methods: Using the tensor, we intra-operatively compared the ligament balance measurements of CR and PS TKAs performed at 0, 10, 45, 90 and 135° of flexion, with the patella both everted and reduced. From a group of 40 consecutive females (40 varus osteoarthritic knees) blinded to the type of implant received, we prospectively randomized 20 patients to receive a CR TKA (NexGen CR Flex) and the other 20 patients a PS TKA (NexGen LPS Flex). The CR TKA group had a mean age of 73.7 ± 1.3 years while the PS TKA group had a mean age of 73.8 ± 1.7 years.

Results: The mean values of varus angle in CR TKA with the knee at 0, 10, 45, 90 and 135 degrees of flexion were 3.0, 3.2, 2.7, 4.2 and 5.1 ° with the patella everted, and 3.9, 4.2, 2.5, 2.0 and 2.0 ° with the patella reduced. The mean values of varus angle in PS TKA at these same degrees of flexion, respectively, were 3.0, 4.1, 6.0, 6.2 and 6.1 ° with the patella everted, and 3.8, 4.1, 6.3, 6.3 and 4.9 ° with the patella reduced. While the ligament balance measurements with a reduced patella of PS TKAs slightly increased in varus from extension to mid-range of flexion (p< 0.05), these values slightly decreased for CR TKA (p< 0.05). Additionally, the ligament balance at deep knee flexion was significantly smaller in varus for both types of prosthetic knees when the PF joint was reduced (p< 0.05).

Conclusion: Accordingly, we conclude that the ligament balance kinematic patterns differ between everted and reduced patellae, as well as between PS and CR TKA.


A.J. Petrella J. Armstrong V. Patel P.J. Laz P.J. Rullkoetter

Cross-shear has been shown to increase ultra-high molecular weight polyethylene (UHMWPE) wear in pin-on-disk, total knee, total hip, and spinal disc replacement testing. Computer modelling of implant wear holds promise for improving efficiency in the development of new implant designs, but it is desirable to accurately account for the effects of cross-shear in the computational simulation. Several studies have sought to propose a quantitative metric for cross-shear in multidirectional sliding and to correlate average cross-shear intensity with apparent wear rate measured in experiments. The apparent wear rate accounts for the total volume loss from all points on the UHMWPE surface. In principle, if the cross-shear metric correlates with experimental wear rates, it is then possible to predict an estimated wear rate for any arbitrary set of kinematic inputs. UHMWPE wear may then be simulated numerically with some form of Archard’s law.

One limitation of the above approach is that counter-face kinematics are homogenized by the use of a spatially and temporally averaged apparent wear rate. In a sliding contact interface of a joint implant in vivo, the intensity of cross-shear wear may vary with time and location on the surface. To address this variation we have proposed a novel cross-shear metric (x*) and developed a modified form of Archard’s law that is capable to differentiate between unidirectional and multidirectional sliding wear. The wear model and x* have been implemented in an explicit finite element framework (ABAQUS) that is capable of quantifying wear from any number of wear surfaces (e.g., front side, backside, post) with completely general geometry and loading conditions.

Preliminary validation of x* and the wear model have been performed by comparison with data from the open literature. Cross-shear metric x* is easy to compute, exhibits invariance to the choice of kinematic reference frame, and is able to reliably distinguish between similarly shaped sliding paths of different lengths – all improvements compared to cross-shear metrics described elsewhere. The wear model that incorporates x* has shown good agreement with pin-on-disk and cervical disc replacement wear results previously reported. Ongoing research focuses on demonstrating similar validity of the model for cross-shear wear in hip and knee replacements.


K. Kobayashi M. Sakamoto T. Kimura K. Shin Y. Tanabe G. Omori Y. Koga

In order to understand the actual weight-bearing condition of lower extremity, the three dimensional (3D) mechanical axis of lower limb was compared with the loading direction of ground reaction force (GRF) in standing posture.

Three normal subjects (male, 23–39 yo) participated in the study. A bi-planar radiograph system with a rotation table was used to take frontal and oblique images of entire lower limb. Each subject’s lower limb was CT scanned to create 3D digital models of the femur and tibia. The contours of the femur and tibia in both radiographs and the projected outlines of the 3D digital femur and tibia models were matched to recover six-degree of freedom parameters of each bone. The 3D mechanical axis was a line drawn from the centre of the femoral head to the centre of the ankle. A surface proximity map was created between the distal femoral articular surface and the proximal tibial articular surface. A force plate was positioned on the rotation table to measure GRF during biplanar X-ray exposure. Each subject put one’s foot measured on the force plate and the other on the shield. Bi-planar radiographs were taken in double-limb standing, double-limb standing with toe up in the leg measured, and single-limb standing. The anterior and medical deviations of the loading direction of GRF from the 3D mechanical axis were determined at the proximal tibia and normalized by the joint width in anteroposterior direction and by the joint width in lateral direction.

For all subjects the passing points of the 3D mechanical axis at the proximal tibia were almost in the middle of the joint width in lateral direction. Compared to the 3D mechanical axis, the loading direction of GRF passed through the anterior region in double-limb standing and single-limb standing, and anteromedial region in single-limb standing. The normalized medial deviation was significantly greater in singlelimb standing than in double-limb standing (p=0.023). The separation distance tended to decrease in the medial compartment in single-limb standing, and to increase in toe up in the entire region.

Deviation of the loading direction of GRF from the 3D mechanical axis at the proximal tibia varied among standing postures, relating to the change in weightbearing condition as indicated in the separation distance map. These results provide the mechanical perspective related to the causes and progression of knee OA and may contribute to the improvement of surgical treatments such as arthroplasty and osteotomy.


K. Ishida T. Matsumoto S. Kubo N. Tsumura A. Kitagawa M. Kurosaka R. Kuroda

Background: The use of computer-assisted navigation system had proved to result in consistently accurate alignment of prosthesis in total knee arthroplasty (TKA), however, the clinical midterm to long-term results remains unclear. The objective of this study is to investigate whether clinical results after computer-assisted TKA is superior to the conventional surgical method at midterm, minimum for 5 years follow-up.

Materials: From October 2002 to May 2003, we implanted 30 posterior stabilized total knee prostheses (PFC Sigma; DePuy Inc) using a computed tomography-free navigation system (Vector Vision) for patients diagnosed as osteoarthritis. A control group of 30 matched total knee prostheses of the same type were implanted via a classical, surgeon-controlled technique. Midterm 5 year clinical results including range of motion and Knee Society Clinical Rating Score were compared with these groups. The navigation group was comprised of 23 women and 4 men with a mean age of 81.0 years (range: 56–89 years) at final follow-up and the manual group was comprised of 23 women and 4 men with a mean age of 78.2 years (range: 51–87 years).The results were analyzed statistically and differences of p < 0.05 were considered statistically significant.

Results: Mean follow-up duration was 68.9 months (range: 60–78 months) in the navigation group and 72.8 months (range: 60–80 months) in the manual group. Total 6 patients (3 patients in each group) were lost to follow-up because of their death or lost contact. The follow-up rate was 90 %. No revision or reoperations were required in this study. The average preoperative knee society knee score (KSS) and knee society functional score (KSFS) in the navigation group were 52.9 points (range: 43–77 points) and 51.4 points (range: 25–80 points), respectively and the average postoperative scores were 89.7 points (range: 64–100 points) and 79.7 points (range: 40–100 points), respectively. The average preoperative KSS and KSFS in the manual group were 50.7 points (range: 43–77 points) and 50.3 points (range: 10–80 points), respectively, and the average postoperative scores were 89.6 points (range: 70–100 points) and 75.2 (range: 5–100 points), respectively. No significant differences were noted between the two groups both pre-and postoperatively. The average preoperative range of motion (ROM) in the navigation group was 105.0° (75°–125°); −8.6° (range: 0° to −25°) for extension and 113.6° (range: 85°–135°) for flexion, respectively. The average postoperative ROM was 113.8° (85°–130°); −1.0° (range: 0° to −10°) for extension and 117.0° (range: 105°–130°) for flexion, respectively. The average preoperative ROM in the manual group was 102.5° (65°–140°); −10.2° (range: 0° to −25°) for extension and 112.7° (range: 75°–140°) for flexion, respectively, the average postoperative ROM was 106.9° (80°–130°); −0.0° (range: 0°) for extension and 106.9° (range: 80°–130°) for flexion, respectively. Although no significant difference was found between preoperative ROM for the two groups, the navigation group showed a significantly better ROM compared to the manual group.

Conclusions: Minimum 5-year follow-up of computer-assisted TKA used in the present study revealed that better ROM was achieved, compared with the conventional surgical method. KSS and KSFS were equally good among these two groups. The results focused on the radiographically malaligned patients and further longer follow-up were needed to reveal whether computer-assisted TKA has true clinical benefits compared with the conventional surgical method.


W. McGann J. Peter K. Liddle J.M. Currey M. Marmor J.M. Buckley

Achieving the correct inclination angle for the acetabular component in total hip arthroplasty (THR) can be technically challenging. The aim of this study is to validate the use of a simple, laser-guided system to address the acetabular cup inclination angle intraoperatively and quantify its accuracy and repeatability across users.

A simple inclinometer system was manufactured, consisting of a laser that snaps into both the inclinometer and the handle of a standard trial cup impacter. The system functions as follows:

desired inclination angle is set on the inclinometer,

inclinometer is positioned on the acetabulum,

laser beam is projected onto and marked on a screen outside of the surgical exposure,

the impacter is reoriented in the acetabulum until the laser beam aligns with the recorded mark on the screen.

A validation study was performed on this system using intact cadavers (N=4). A THR-specific. Trial acetabular components were installed unilaterally in each donor using both the laser inclinometer system with an in-line mounted intraoperative navigation system (NaviVision, Vector Vision Hip 3.1, BrainLab) serving as the measurement standard. Three orthopaedic surgeons participated in the study, two experienced with the device (“experts”) and one “novice”, and each surgeon performed two sequential validation experiments:

10 trials at a set device inclination angle, and

5 trials of matching the trial cup placement to this set angle.

Using the laser-guided system, the inclination angle of the trial cup deviated from the desired orientation by 1.1±0.9° (mean st. dev; range: 0–3°) for all specimens across all operators. The corresponding error in anteversion angle was 1.4±1.3° (range: 0–5°). There was no difference in inclination angle between expert and novice surgeons (1.0±0.8° versus 1.1±1.2°, respectively; p> 0.10 for unpaired t-test). To set the desired inclination angle on the trial cup, original and final laser target positions were within 4.1±2.5 cm at 1 m screen placement.

Results suggest that the laser-guided system has sufficient accuracy and repeatability for use intra-operatively. Inclination angles differed from prescribed angles by 1° on average, and malalignment in anteversion was subclinical, ≤5° for all cases. Furthermore, the tolerance for laser re-alignment sufficiently large (5–10 cm) to make the device functional intraoperatively. Future work will focus on expanding the sample size and correcting simple design limitations in the device.


Robert Thornberry

Navigation and hip impingement simulation software has been available for over 10 years.

Although hip implant retrieval analysis supports a clinical need for hip navigation, the current commercially available systems fail to provide the level of accuracy, cost, ease of use, and intraoperative functionality to be widely accepted. With the addition of highly accurate hip motion simulations that model all possible combined hip motions, it is felt hip navigation can become both simpler and more robust. A new navigation system is proposed that should operate with an increased level of accuracy, ease of use, and functionality.

Materials and Methods: Simulations of native and implant hip motions to impingement were modeled in HipNav a noncommercial validated hip navigation and simulation program. Implant simulations and simulations based on 30 normal hip high resolution CT scans were performed. Further, 30 normal cadaver hips were studied by optical tracking navigation technologies with modified BrainLab Vectorvision software. The results were graphic represented in 3-D data graphs representing all normal combined hip motions. Flexion/extension was graphed on one axis, abduction/adduction and internal rotation/external rotation on the other two axes. The graphs were modeled in Maple software and then for ease of presentation converted to 3D StudioMax for clarity. The simulations were also performed on CAD implant models all implantation positions within 2 standard deviations of implantation error. This was based on current CT based literature on hip implantation variability. Modeling of augmented cup liners and liner positions as well as modeling of 28mm, 32mm, and 36 mm femoral head sizes were also performed. Graphic representations of all hip motion studies were superimposed on other normal motion graphs clearly demonstrating any range of motion deficiencies. A proposed “gizmo” femoral head neck trial device (with a unique neck geometry that forces impingement) was modeled in all optimal and sub-optimal orientations. Ranges of motion simulations to impingement were then recorded. This created unusually shaped “tube graphs” of a unique character. These unique data graphs provide a “fingerprint” of the relative orientation of the femoral and acetabular components. These data sets are then stored as a reference. When performing a range of motion to impingement intra-operatively with the “gizmo” trial head/neck device, this “fingerprint” can be kinematicly obtained and matched to one of the stored reference files. This method allows the determination of implant orientations without a registration step.

Results: Many questions regarding implant positioning, head size, use and placement of augmented liners were readily and clearly demonstrated with this methodology. The 28 mm head implants could not recreate the normal hip motions that were recorded from the cadaver studies regardless of implant position. Augmented liners increased impingement to a dramatic degree when place in the posterior or superior positions. The loss of motion to impingement due to these augmented liners was equivalent to over-anteverting the cup 30 degrees. The “gizmo” device due to its large neck and unique geometry is able to force impingement resulting in the creation of unique data sets that can determine combined anteversion and cup abduction without CT, or any registration of the pelvic plane and with the patient in any position on the OR table. The use of statistical shape modeling of individual patient X-rays will further improve accuracy of this methodology.

Discussion: This method of combining the strengths of navigation and simulation creates a powerful new tool that may allow intra-operative hip navigation to become commonplace and improve the ability of the surgeon to provide a more successful and predictable surgical result for his patients The problems of ease of use, accuracy and intra-operative functionality are significantly improved with this new proposed method. The addition of this technology to existing optical tracking systems is not difficult and the additional hardware and software required to implement this solution is readily available. The ability of this method not to require a preoperative CT or intra-operative pelvic plane registration eliminates all registration errors as a contributing cause of overall combined implantation error. Although inherently reasonable, this proposed method is not yet commercially available and has not been clinically proven to reduce dislocations and impingements in patients. It remains a work in progress.


Jean-Manuel Aubaniac Sebastien Parratte Jean-Noel A. Argenson

Treatment of limited osteoarthritis of the knee remains a challenging problem. Total knee arthroplasty may provide a reliable long-lasting option but do not preserve the bone stock. In another hand, compartmental arthroplasty with or without osteotomy is a bone and ligament sparing solution to manage limited osteoarthritis of the knee. Considering the renewed interest for combined compartmental implants we aimed to evaluate the average 12-year clinical and radiological outcome of a consecutive series of patients treated with compartmental knee arthroplasty combined or not with osteotomy.

We retrospectively reviewed all 255 patients (274 knees) treated in our institution with a compartmental arthroplasty combined or not with an osteotomy for a diagnosis of either bi or tricompartmental osteoarthritis of the knee between April 1972 and December 2000. The series included: 100 cases of combined lateral and medial UKA, 77 combined medial UKA and patello-femoral arthroplasty (PFA), 19 cases of combined Bi-UKA and PFA, 14 cases of UKA and high tibial osteotomy (HTO), 7 cases of combined lateral-UKA and PFA and HTO, 16 cases of combined lateral-UKA and PFA and 13 cases of combined bi-UKA and HTO.

Patient’s selection and surgical indication was based on the physical exam and on the radiological analysis including full-length x-rays and stress x-rays. Clinical and radiological evaluations were performed at a minimum follow-up of 5 years (mean, 12 years; range, 5–23 years) by an independent observer.

The Knee Society knee and function scores improved respectively from 43 to 89 and from 47 to 90 at last-follow-up. The mean active knee flexion improved from 116° ± 6° (range, 100°–145°) pre-operatively to 129° ± 5° (range, 117°–149°) at final follow-up. The restoration of the mechanical axis of the knee was achieved in all the cases. Dramatic failures were observed for patient with uncemented PFA. Considering revision for any reason as the endpoint, the 17-years survivorship was 0.68 (95% confidence interval: 0.62 to 0.75).

Our results suggested that combined compartmental arthroplasty with or without osteotomy can restore function and alignment of the knee in compartmental arthritis. This combined surgery represents a bone and ligament sparing alternative to TKA which can be considerate as a true minimally invasive solution.


R. Koerver I.C. Heyligers S. Samijo B. Grimm

Introduction: In clinical orthopaedics questionnaire based outcome scores such as the DASH shoulder score suffer from a ceiling effect, subjectivity and the dominance of pain perception over functional capacity. As a result it has becomes increasingly difficult to clinically validate medical innovations in therapy or implants and to account for rising patient demands. Thus, objective functional information needs to be added to routine clinical assessment. Motion analysis with opto-electronic systems, force plates or EMG is a powerful research tool but lab-based, too expensive and time consuming for routine clinical use. Inertia sensor based motion analysis (IMA) can produce objective motion parameters while being faster, cheaper and easier to operate. In this study a simple IMA shoulder test is defined and

its reliability tested,

its diagnostic power to distinguish healthy from pathological shoulders is measured and

it is validated against gold standard clinical scores.

Methods: An inertia sensor (41x63x24mm3, 39g) comprising a triaxial accelerometer (±5g) and a triaxial gyroscope (±300°/sec) was taped onto the humerus in a standardised position. One-hundred healthy subjects without shoulder complaints (40.6 ±15.7yrs) and 40 patients (55.4 ±12.7yrs) with confirmed unilateral shoulder pathology (29 subacromial impingement, 9 rotator cuff pathology, 2 other) were measured. Two motion tasks (‘hand behind the head’ and ‘hand to the back’) based on the Simple Shoulder Test (SST) were performed on both shoulders (three repetitions at self selected speed). Motion parameters were calculated as the surface area described by combing two angular rate signals of independent axes (ARS) or by combing the angular rate and the acceleration of a single axis (COMP score). The relative asymmetry between two sides was scored.

Results: The test produced high intra-(r2≥0.88) and inter-observer reliability (r2≥0.82). Healthy subjects scored a mean asymmetry of 9.6% (ARS) and 14.6% (Comp). Patients with shoulder complaints showed > 3× higher asymmetry (ARS: 34.1%, Comp: 42.7%) than the healthy controls (p< 0.01). Using thresholds (ARS: 16%, Comp 27%) healthy and pathological subjects could be distinguished with high diagnostic sensitivity (e.g. ARS: 97.5% [CI: 85.3–99.9%]) and specificity (e.g. COMP: 85.5% [CI: 76.1–91.1%]). Both asymmetry scores were strongly intercorrelated (r2=0.76) as were the clinical scores (r2=0.62, DASH-SST). Asymmetry and clinical scores were hardly correlated (r2< 0.14).

Discussion: The IMA shoulder test and asymmetry scores showed high reliability meeting or exceeding common clinical scores. With a fast assessment of a simple ADL tasks (test duration < 60s) it was possible to provide diagnostic power at clinically usable level making routine clinical application feasible even by nonspecialist personnel. Weak correlations with the clinical scores show that the new test adds an objective functional dimension to outcome assessment which may have the potential to differentiate new treatments or implants required to trigger new therapeutic innovation cycles. Similar motion tests and parameters could also serve lower extremity outcome assessment.


E.R. Pritchard M.R. Mahfouz

Ligament balancing can be difficult to perfect in total knee arthoplasty (TKA), where current surgical practice is subjective and highly dependent on the individual surgeon. Proper ligament balancing contributes to postoperative stability, prosthetic alignment, and proprioception. Conversely, imbalance is linked to increased wear rates of the polyethylene component within the implant and, in turn, early surgical revision. With the end goal of quantification of joint compartmental pressures, pressure sensor arrays have been designed to quantify contact stresses within the knee during TKA.

Flexible, capacitive pressure sensors are designed as simple parallel plates, enabling a robust solid state design. Modification of cleanroom microfabrication processes enable realization of these arrays on polyimide (common in microdevices), and polyethylene (common in joint replacements). Readout circuitry implements an Analog Devices capacitance to digital chip and output is compared to direct LCR meter data. Testing verifies the highly linear response of the sensors with applied normal loads corresponding to pressure magnitudes present in passive (intraoperative) knee flexion. Spatial resolution of the arrays is 0.5 mm, with a critical dimension of 25 micrometers, allowing the magnitude and location of forces to be accurately recorded.

The MEMS pressure sensors are mounted on a tibial trial, with the body of the trial housing all circuitry. The sensors are read sequentially, and the data undergoes analog to digital conversion prior to wireless data transmission at 2.4 GHz. An Instron machine is used for compressive loading for laboratory calibration and testing. This paper outlines device fabrication, readout circuit implementation, and preliminary results.


Y. Kawasaki H. Egawa N. Yasui

Vascular injury associated with hip surgery is a rare but serious complication. Hip surgeons need to understand the vascular anatomy around the acetabulum to avoid vascular injury. The aim of this study was to visualize the pelvic vascular structures thorough the osseous acetabulum using 3DCT angiography and to describe the three-dimensional relationship between the vessels and the acetabulum. A total of 100 patients who took 3DCT with intravenous contrast for intra-pelvic neoplastic disease were randomly chosen. Those patients with hip disease were excluded. Three examinations were performed.

First, dual-phase helical CT data were transferred to a workstation (M900;Zio,Tokyo,Japan) and 3D visualizations of the vascular structures through the pelvis were reconstructed.

Second, location of the external iliac, femoral and obturator vessels were investigated in axial CT images. Finally, influence of the age factor on the anatomical courses of the external iliac vessels was assessed.

Reconstructed 3D images were able to provide spatial relationship between courses of the pelvic vascular structures and the acetabulum. We could visualize the pelvic vascular structures thorough the pelvis from similar operative viewpoints. Axial CT examinations revealed the external iliac vessels locate very closely to the pelvis as they exit the pelvic cavity.

Especially, the left side vessels and vein were closer to the pelvis. The femoral vessels became closer to the acetabular edge with traveling distally. At the distal half of the acetabulum, the femoral vessels located just ventrally to the anterior acetabular edge. The obturator vessels courses inferiorly along the quadrilateral surface behind the acetabulum, they became very close to the inner cortex or the acetabulum. Straight type of the anatomical course of the external iliac vessels was the most common configuration in young patients, curved and the tortuous types were present in older patients.

The results of this study are useful to understand the anatomical orientation of the vessels around the acetabulum. To avoid vascular injuries in hip surgery, knowledge of the vascular orientation is of critical importance for the hip surgeon.


A F. Raaii B.J. Roessler D.C. Markel

Numerous investigators have described chondrogenic differentiation of bone marrow stromal cells obtained from both murine and human sources over the past decade. The ease of access and large available quantity of adipose tissue, however, makes Adipose-Derived Stem Cells (ADSC) a far more practical alternative for clinical applications.

Therefore, the primary goal of this research endeavor is to achieve chondrogenic differentiation of ADSC. Previous work had also demonstrated that bone morphogenetic protein receptor 1A (BMP receptor 1A) signaling is required for postnatal maintenance of articular cartilage. In fact, cartilage within the joints of transgenic mice deficient in BMP receptor 1A rapidly degenerates after birth in a process resembling accelerated human osteoarthritis. Based on this evidence, we used a lentiviral vector to increase expression of BMP receptor 1A by our isolated stem cells in order to direct their differentiation into the chondrocyte lineage.

We harvested subcutaneous adipose tissue intraoperatively from consenting patients undergoing elective lipoplasty and panniculectomy procedures. The stromal vascular fraction was isolated from this tissue and further refined by passaging in selective media to yield a stable population of ADSC in primary culture. Both the identity and homogeneity of this stem cell population was confirmed using adipogenic induction media and differentiation cocktails. In addition, we subcloned an expression plasmid containing the BMP receptor 1A locus in tandem with green fluorescent protein (GFP) under the transcriptional control of a single promoter. This plasmid was packaged into a lentiviral vector to provide a reliable method of achieving both genomic integration and long-term expression of the BMP receptor 1A gene. Hence, transduction of ADSC using this vector resulted in overexpression of BMP receptor 1A by these multipotent cells.

The GFP was then utilized to screen and enrich the ADSC population for stem cells with a robust expression of BMP receptor 1A. The ADSC that overexpressed BMP receptor 1A were found to achieve chondrogenic differentiation after 13 to 16 days of in vitro culture, as revealed by immunohistochemistry assays for the bio-markers of articular cartilage (type II collagen and the proteoglycan aggrecan).

Our results demonstrate that stem cells derived from the adipose tissue of a patient represent a viable means of culturing autologous chondrocytes in vitro for future implantation at the site of osteochondral defects. This method of attaining cartilaginous regeneration is intuitively appealing, given the minimal donor site morbidity associated with removing subcutaneous fat. By transducing the ADSC with a lentiviral vector, we have also collected further evidence implicating the critical importance during chondrogenesis of signaling mediated by the BMP receptor 1A. Further tissue engineering studies are now in progress to evaluate the ability of ADSC to differentiate into chondrocytes after seeding onto poly-caprolactone polymer scaffolds.


M.J. Kuhn M.R Mahfouz

Wireless technologies and their use in the medical field have become much more widespread and important in the last decade. Whether it is a doctor carrying a personal digital assistant, the hospital WLAN, RFID asset tracking systems, telemetry-based Point-of-Care systems, or implanted wireless devices, wireless systems play an important role in the underlying technologies utilized by a hospital. Conversely, wireless technologies are not widely used in computer assisted orthopaedic surgery (CAOS), mainly due to their poor performance in the operating room (OR). The large amount of metallic interference found in the OR can severely degrade wireless signals. This can cause failure in wireless digital communication and large errors in 3-D tracking when using wireless signals for 3-D positioning.

We have developed a wireless positioning system based on ultra wideband (UWB) technology which achieves mm-range 3-D dynamic accuracy and can be used for intraoperative tracking in CAOS systems. This system can be used to track smart surgical tools in the OR and also for registration of bones and conventional (non-smart) surgical tools. UWB technology also has the potential for high data rate digital communication. The potential of highly accurate 3-D tracking combined with high data rate digital communication make UWB an attractive wireless technology for future CAOS systems and provides a strong backbone for smart surgical tools.

We have run various experiments with our UWB system in an OR both during orthopaedic surgeries and when the OR was empty. We have obtained time domain and frequency domain data, which has been analyzed to show the effects of transmitting UWB wireless signals in the OR. The implications of the OR environment on 3-D positioning accuracy and also high data rate digital communication will be presented. The final conclusions show the potential of UWB for wireless smart surgical tools which can be tracked in real-time with mm-range and even sub-mm range 3-D accuracy.


H. El Dakhakhni M.R. Mahfouz

An accurate geometrical three-dimensional (3D) model of human bone is required in many medical procedures including Total Knee Arthroplasty (TKA) and computer-assisted surgical navigation. Segmentation of Computed Tomography (CT) datasets is commonly used to obtain such models. However, such a method is expensive and time consuming. We herein propose a novel method for patient specific bone model reconstruction using standard x-ray fluoroscopy, a cheaper and widely available imaging alternative.

Fluoroscopic images are taken at multiple arbitrary viewpoints to provide sufficient information for bone reconstruction. The viewpoints can be obtained by either rotating the imaging source and detector or the patient’s limb of interest. The bone’s pose within the radiological scene in each of the captured images can be estimated by tracking a set of metallic calibration markers within a calibration target, rigidly attached to the limb of interest. Having acquired the required calibration data, a complex iterative scheme is executed to optimize a statistical bone atlas of the bone of interest and the relative pose between the bone and the calibration target.

In order to verify our method, we performed a cadaveric study. A set of rigidly attached fiducial markers were attached to a cadaveric leg. The leg was imaged using x-ray fluoroscopy while being rotated axially to provide us with the images required for bone model reconstruction. Distal femur and proximal tibia bone models were reconstructed from the fluoroscopy images. Furthermore, the leg was CT-scanned and segmented to provide us with the ground-truth required for reconstruction accuracy assessment. Results show the adequacy of the proposed method for surgical applications.


M.A. Rosa G. Gosheger S. Mauro B. Rossi N.M. Gangemi M. Sanguinetti G. Maccauro

Introduction: It is noted that infections make up the most feared complications of prostheses’ surgery in orthopaedic implants after resection of primary or secondary cancer of limb bones. The causes must be attributed to the entity of the skeletal resection and of surrounding soft tissues sacrifice, to the duration of surgery and to the pre-operative cycle of chemotherapy or radiotherapy. Infections of prostheses in oncology are caused mainly by bacteria present either in isolated strains or in poly-microbic associations, and most recently fungus infections have begun to be found, in immunodepressed patients. Candidemia makes up an important cause of systemic infections in immuno-compromised oncological patients, who received high doses of chemotherapy; moreover candidemia represents a high risk of hospital sepsis. It is noted that the behaviour of the Candida is interpreted through the production of a biofilm and then the inhibition of the production of the biofilm itself is translated into a potential antifungal effect. From the analysis of the literature a protective role carried out by the silver coating of the tumoural prostheses towards the bacterial infections is deduced. It is noted, in fact, the antimicrobiotic effect of medical devices coated in silver; in particular in studies conducted in animals favourable results were demonstrated on bacterial adherence of titanium devices coated with silver. The aim of the study was to evaluate in vitro the inhibition of the production of biofilm by different strains of Candida in the presence of titanium and titanium coated with silver.

Materials and Methods: Six strains of Candida were analyzed: 2 strains of C. albicans, 2 of C. tropicalis and 2 of C. parapsilosis. The fungal strains were stratified on discs of pure titanium, a material in which implants of tumoural prostheses are made, and furthermore on discs of titanium coated in silver, and the ability of the fungus to produce protective biofilm on different substratum was evaluated. All of the studies were conducted 3 times. The adherence to the biofilm was measured by semi-quantitative, colormetric and spettrophotometric methods according to standardized protocols.

Results: The spettrophotometric analysis demonstrated a statistically significant reduction of the production of biofilm by fungus strains that came in contact with titanium coated in silver compared to pure titanium in all of the strains that were examined, attested by the fact that the silver creates a micro-environment unfavourable for fungus growth.

Conclusion: The analysis of the results demonstrated that the Silver coating of the oncological prosthesis made an unfavourable micro-environment not only for bacteria, as has already been widely established, but also for fungus. For this reason we maintain that this coating constitutes a valid opportunity in oncological resections for those patients who, being treated with chemotherapy, radiotherapy and to long hospitalitations present an elevated risk of fungal infection in oncological resections. From the studies we conducted it appeared how fundamental the use of silver in tumoural prosthesis is in order to prevent contamination by fungal strains and how this use must be taken more and more into consideration to improve life expectancy of a particular and sensitive category of patients, especially oncological.


R. Magetsari C.R. Hilmy H.C. van der Mei H.J. Busscher J.R. van Horn

The socio-economic conditions in many developing countries impede widespread general use of the assets of biomedical technology. In orthopedics this becomes evident from the large-scale, though illegal, reuse of osteosynthesis plates and screws. Scientific research into the issue of the safe reuse of osteosynthesis materials from a biological point of view has never been done. Therefore the aim of this study is to determine whether plates and screws after simple cleaning, applying means which are available in developing countries, are safe from a biological point of view. Cleaning methods evaluated include a toothbrush, water, detergent and bleach. X-ray photoelectron spectroscopy analysis of cleaned surfaces and water contact angle measurements indicate that application of these methods yield surface characteristics similar to those of new, sterilized plates. If desired, bleach can be applied without affecting the surface properties of the materials.

Subsequently, the reactivity of a mammalian monolayer in response to a used screw (ISO-10993-5) and endotoxin release (USP 27-NF 22) was evaluated, showing that all screws tested are non-cytotoxic with endotoxin release within the requirements of the FDA. This study shows that reuse is not necessarily unsafe from a biological point of view.


N.G. Dong M. Thakore M. Nogler T. Lovell P. Merritt S. Kreuzer L. Puri W. Hozack

Taper locking connection has been widely used in orthopedic implant devices. The long term successful clinical results indicated it is a safe and effective structural component. The common materials used are solid titanium and cobalt chromium alloys. Recently, foam metal materials showed promising results of bony in-growth characteristics and became the excellent choices for the orthopedic implants. Clinically it is desirable to taper lock the foam metal component to other structural components. To date there is no data for the foam metal being used directly in taper connection. The purpose of this study was to investigate the static locking strength of the taper junctions made of titanium foam metal comparing to that of conventional solid titanium material.

(5) 43mm long and 4mm thick sleeve were machined internally with 17mm major diameter and 3° included taper angle for each 70% porosity CP titanium foam metal and solid Ti6AL4VELI alloy materials. (10) Solid Ti6AL4VELI alloy stems were machined with OD geometry matching the ID of the sleeves. All components were inspected, cleaned and assembled to (5) pairs of each sleeve material combinations with 2224N axial compression force. Each assembled specimen was mounted on MTS Bionix test machine for torque resistance test. The angular displacement at 0.1 degree/sec was applied to the stem when sleeve was rotationally locked. The maximum torque resistance was recorded. The specimen was then re-assembled with 2224N axial compression force. Axial push out test was performed by loading at smaller end of the stem when the opposite end of sleeve was supported. The maximum push out force was recorded. Procedures were repeated for all foam metal and solid metal specimens. The taper interface surfaces were visually inspected to compare two types of sleeve materials.

The average torque resistance for foam metal and solid tapers were 20.4Nm (SD=3.68) and 21.7Nm (SD=3.72) respectively (p=0.59). The average axial locking forces were 2035.7N (SD=201.11) for foam metal taper and 1989.3N (SD= 451.84) for solid taper (p=0.839). There was no visual difference observed for tested stem outer and sleeve inner surfaces of foam metal and solid metal pairs.

This study suggested that the foam metal sleeve is capable to have comparable taper locking strength as the conventional solid taper components under dry static condition. The study indicated that the contact area does not significantly influence the friction locking. This is in agreement with the friction force definition which depends only on the coefficient of friction and normal contact force.


F. Namavar R. Sabirianov J.D. Jackson R. Namavar J.G. Sharp K.L. Garvin H. Haider

The steric and electrostatic complementarity of natural proteins and other macromolecules are a result of evolutionary processes. The role of such complementarity is well established in protein-protein interactions, accounting for the known protein complexes. To our knowledge, non-biological systems have not been a part of such evolutionary processes. Therefore, it is desirable to design and develop nonbiological surfaces, such as implant devices (e.g. bone growth for non-cemented fixation), that exhibit such complementarity effects with the natural proteins.

Cell attachment and spreading in vitro is generally mediated by adhesive proteins such as fibronectin and vitronectin [1]. The primary interaction between cells and adhesive proteins occurs through integrin and an RGD amino acid sequence. The adsorption of adhesive proteins plays an important role in cell adhesion and bone formation to an implant surface [1]. The ability of the implant surface to adsorb these proteins determines its aptitude to support cell adhesion and spreading and its biocompatibility. For example, the enhancement of osteoblast precursor attachment on hydroxyapatite (HA) as compared to titanium and stainless steel was related to increased fibronectin and vitronectin absorption [2].

The role of surface characteristics, such as topography, has been studied in recent years without the emergence of a comprehensive and consistent model [1]. For example, while no statistically significant influence of surface roughness on osteoblast proliferation and cell viability was detected in the study of metallic titanium surfaces [3], the TiO2 film enhances osteoblast adhesion, proliferation and differentiation upon an increase in roughness [4].

We designed and produced ceramic [5] and metallic coatings via an ion beam assisted deposition process with spatial dispersion (roughness) comparable to the size of proteins (3–20nm). Our ceramic and cobaltchrome (CoCr) coatings exhibit high hardness and contact angles with serum of 0° and 40° to 50°, respectively. Furthermore, our theoretical calculations and quantum-mechanical modeling clearly indicate that the spatial electric potential variation across our designed ceramic surfaces is comparable to the electrostatic potential variation of proteins such as fibronectin, promoting increased absorption on these surfaces. Therefore, an increase in the concentration of adhesive proteins on the designed surfaces results in the enhancement of the focal adhesion of cells. Our experimental results of the adhesion and proliferation of osteoblast-like stromal cells from mouse bone marrow indicate that our nanostructured coatings are three to five times better than growing on HA and orthopaedic grades of titanium and CoCr. Our results are consistent with the steric and electrostatic complementarity of nanostructured surfaces and adhesive proteins. This paper presents the adhesion and proliferation of osteoblast-like cells on micro-and nanostructured surfaces and provides new models describing the mechanism responsible for the enhancement of cell adhesion on nanostructured ceramic and metallic surfaces compared with orthopaedic materials.


S.T. Ball J.B. Hulst G. Wu M. LeDuff H.C. Amstutz

Recently, monoblock cups have increased in popularity for hip resurfacing and large femoral head total hips. However, there have been no studies specifically evaluating the durability of this type of cup. The purpose of this study was to define the mid-term survivorship of cobalt-chrome alloy, monoblock acetabular components.

A retrospective radiographic review of 426 consecutive hip resurfacings using the ConserveÒPlus prosthesis was performed with specific attention to the acetabular component.

Radiographs were analyzed for cup position, the presence of radiolucencies, cup migration, bead shedding, osteolysis and stress remodeling of the pelvic bone. Kaplan-Meier (KM) survival estimates were calculated using revision for aseptic loosening of the acetabular component as the end point.

Average follow-up was 8.6 years (range 5.4 to 12.3). Mean abduction angle and anteversion angle were 46.6° (± 6.8°), and 21.6° (± 8.6°), respectively. Radiolucent gaps behind the cup from incomplete seating were visible in zone 2 in 16% of cases. These were typically 1 to 2 mm in size and radiographically filled in all but 2 cases. No cups with early lucencies went on to fail. Late radiolucencies developed in zone 1 in 8 cups (1.9%), in zone 2 in 8 cups (1.9%), and in zone 3 in 19 cups (4.5%). Radiolucencies in multiple zones were seen in 6 cups (1.4%).

Small amounts of socket migration (2mm or less) were suspected in 3 cups (0.7%) but each of these has remained stable. There were no cases of bead shedding. Small osteolytic lesions were suspected in 12 hips (2.8%). There were 2 revisions for aseptic loosening of the cup at 5 and 8 years, and one revision for protrusion of the cup through the medial wall 4 days after surgery.

Additionally, one cup at 9 years follow-up is believed to be loose but has yet to be revised. The KM survival estimate was 99.6% at 5 years (95% C.I. 98.4% to 99.9%) and 98.7% at 10 years (95% C.I. 94.5% to 99.7%).

In conclusion, this study demonstrates excellent mid-term survivorship of a cobaltchrome alloy monoblock acetabular component, which matches that of conventional titanium implants. Small early gaps seen behind the cup from incomplete seating do not appear to effect cup survivorship as long as a good peripheral press-fit is obtained. Osteolysis with this prosthesis is rare but does occur.


S.D. Cook S.L. Salkeld L.P. Patron

Pyrocarbon has been used for over 25 years in finger joint replacements. Excellent biocompatibility, material and wear properties make pyrocarbon ideal for an orthopaedic device.

Pyrocarbon implants incur significantly less wear to articular cartilage than metal implants. The pyrocarbon implant replacement device (PIR) was developed to treat focal chondral and osteochondral defects of the femoral condyles. The PIR is intended to treat defects not amenable to microfracture or similar regenerative techniques and those for which unicompartmental or total knee arthroplasty is not yet indicated. The purpose of this study was to evaluate the in vivo articular response to the PIR device and compare it to a similar device made from cobaltchromium (CoCr) device. In addition, bone fixation of the PIR device with and without hydroxyapatite (HA) coating was evaluated.

Nine adult bred-for-purpose beagles received bilateral 6mm medial condyle full thickness osteochondral defects. One defect was treated with a PIR device and the other an identical CoCr device. In addition, one HA-coated and one non-HA coated PIR device was placed unicortically in the lateral distal femurs of each animal. Three animals each were terminated at 12, 24, and 52 weeks postoperative. Non-decalcified histologic sections of the implanted condyles and decalcified sections of the medial tibia and meniscus were evaluated. The femoral condyle sections were graded using a modified scale of Kirker-Head (2006). Additionally, the bone– implant contact area was quantified. The tibia-meniscus sections were evaluated utilising a modified version of the ICRS Histological Visual Scale (2002). The lateral distal femur implants were mechanically tested in axial push-out to compare the bone-implant interface strength between the HA-coated and non-HA coated PIR devices.

The mean histologic grades for the tibia and meniscus were superior for surfaces that articulated against the pyrocarbon PIR device compared to the CoCr device at 12, 24 and 52 weeks. Over time, the mean histologic grades decreased with both materials; however, tibias that articulated with the CoCr device had the lowest mean grade at 52 weeks. There were little difference in bone contact 12 and 24 weeks between the pyrocarbon and the CoCr devices. At 52 weeks, less bone contact was observed compared to 12 and 24 weeks. Mechanical testing demonstrated that the HA-coating imparted a statically significant improvement in interface strength as well as greater direct bone contact to the implant.

The results of this study confirm that pyrocarbon provides an ideal surface for an implant that articulates with cartilage of the knee. Although adequate direct bone contact was observed, the addition of HA-coating imparted both superior initial and long term bone fixation. The PIR device is suitable for restoration of focal defects of the knee.


J.K.P. Mueller R. D. Komistek A. Sharma

At present, long-term follow-up studies are used to assess the performance and longevity of an implant, but the downside is that designers must wait 5–10 years before they receive this feedback. Therefore, the objective of this study was to develop a theoretical simulator that will allow for prediction of kinematic patterns based on implant shape and prediction of implant longevity based on the implant’s ability to adapt to in vivo conditions.

A model of the normal lower leg, including muscles and all ligament structures, was developed using Kane’s theory of dynamics. All muscles and ligaments were modeled as distributed loads and included wrapping points to follow the true path of soft-tissue structures.

Currently, two activities are available to the user: leg extension and deep flexion. 3D shapes, pertaining to the implant designs are input to the model.

A validation of the model was conducted using an initial force prediction for each muscle. The predicted kinematics were compared to a library of in vivo kinematics from over 2000 knees obtained using fluoroscopy and a 3-D model fitting technique. If the kinematic patterns from the model were incorrect, an optimization feedback algorithm induced a change in the muscle force. This process continued until the proper muscle force profiles were determined.

Then, using muscle forces which achieve observed motion in TKA previously implanted and analyzed, evaluation of various new implant designs could be assessed.

Altering designs or constraints in TKA lead to quite different kinematic profiles, even when the same muscle force profiles are used. Further research needs to be conducted using more design profiles before multiple implant designs could be evaluated and compared.


P.M. Lewis C.A. Moore M. Olsen E.H. Schemitsch J.P. Waddell

Oxidized Zirconium (Oxinium, Smith & Nephew, Inc., Memphis, TN) is a relatively new material that features an oxidized ceramic surface chemically bonded to a tough metallic substrate. This material has demonstrated the reduced polyethylene wear characteristics of a ceramic, without the increased risk of implant fracture. The purpose of the current investigation was to assess clinical outcomes following primary total hip arthroplasty with Oxinium versus Cobalt Chrome femoral heads.

One hundred uncemented primary total hip arthroplasty procedures were prospectively performed in 100 patients. There were 52 males and 48 females with mean age at the time of surgery of 51 years (SD 11, range, 19–76). Using a process of sealed envelope randomization, patients were divided into 2 groups. Each group contained fifty patients. Those in group 1 received an Oxinium femoral head (OX), while those in group 2 a cobalt-chrome femoral head (CC).

The current study reports clinical outcome measures for both the OX and CC groups at a minimum follow-up of 2 years postoperatively. At the time of latest follow-up, stem survival for both groups was 98%. There was a significant improvement in all clinical outcome scores between preoperative and 2 year postoperative time periods for both bearing groups (p< 0.003). There were no significant differences between bearing groups for any of the clinical outcome scores at final follow-up (p> 0.159). Mean Harris Hip Scores at 2 years postoperatively were 92 and 92.5 for OX and CC, respectively (range; 65–100 OX, 60–100 CC). For SF-12, both the Physical Component Summary Scale (PCS) and the Mental Component Summary Scale (MCS) are reported. Mean PCS scores at final follow-up were 45.2 and 49.21 for OX and CC (range; 27.1–56.7 OX, 26.3–61.8 CC). Mean MCS scores were 53.8 and 52.57 for OX and CC (range; 39.2–65.5 OX, 34.3–64 CC). Mean final WOMAC scores are reported as 84.9 and 87 for OX and CC, respectively.

The current data suggest that total hip arthroplasty utilizing Oxinium femoral heads is safe and effective. Additional follow-up of the current cohort will be performed in order to fully assess mid-to long-term clinical outcomes.


C. Dynybil J. Snel M. Kääb C Perka

Purpose: The objective of the present study was to evaluate whether horizontal cleavage and complex meniscus tears, which supposed to be degenerative tears, are associated with an increase of specific matrix metalloproteinases and an increased incidence of cartilage damage, in comparison with patients having other patterns of meniscal injury1,2.

Materials and Methods: Data were collected prospectively from 32 knee arthroscopies, patients were assigned by intraoperative findings due to their meniscal tear to one of two groups: “degenerative meniscal lesions” (horizontal cleavage and complex tears; n=20) or “traumatic tears” (longitudinal and radial tears; n=12). Patient data (age, duration of symptoms, mechanism of injury, body mass index [BMI]), intra-articular and radiographic findings were recorded. Samples of knee joint fluid were analyzed for the matrix matrix metalloproteinases pro-MMP-1, MMP-3 and pro-MMP-13, which are postulated to be involved in articular cartilage degradation3. Cartilage changes were classified intraoperative by Outerbridge (grade 0–4). Praeoperative bone morphology of the knee joint was graduated by Kellgren-Lawrence (Stadium 0–4). The Knee Injury and Osteoarthritis Outcome Score (KOOS) was used to assess the patients opinion about their knee and associated symptoms and function preoperative and 1.5 years postoperative.

Results: Degenerative meniscus lesions appeared predominantly at the end of fifty years of age (58.5±13.9 years), whereas other patterns of meniscal lesions happened around 30 years of age (28.7±8.1 years; P< .0001; Fig. 1 [Median]). Patients with a degenerative meniscus lesion had marginally overweight, whereas patients with a traumatic tear were in the normal range regarding the body mass index (BMI 23.7±5.3 vs. BMI 26.8±3.9; P=.044). A comparison of patients with horizontal cleavage and complex meniscal tears (“degenerative tears”) to patients with longitudinal or radial (“traumatic”) tears showed for the former increased severity of chondral lesions (Outerbridge: 2.9±1.4 vs 1.1±0.9; P=.001; Fig. 2 [Median]) and radiographic osteoarthritis (Kellgren-Lawrence: 1.9±1.5 vs 0.4±0.5; P=.004; Fig. 3 [Median]). The KOOS improved after arthroscopic treatment in the degenerativemeniscal-tear group as well as in the traumatic-tear group significantly (Total-KOOS Score preoperative: 36.5±30.7 and 38.1±24.8; Total-KOOS Score 1.5 years postoperative: 87.8±6.7 and 49.2±21.9; p=.043 and p=.012; “0” indicates extreme knee problems; “100” indicates no knee problems; Fig. 4 [Median]). Pro-MMP-13 correlated significantly with an increase of chondral lesions and radiographic osteoarthritis (r=.534; p=.003; r=.457; p=.02). MMP-3 concentrations in the synovial fluid of patients with a degenerative meniscus lesion were about 20% higher compared to patients with other patterns of meniscal lesions. No one of the investigated MMPs correlated significantly with a specific meniscal injury (Fig. 5 [Median]).

Conclusions: Complex and horizontal cleavage meniscal tears are not as benign as was previously thought and are highly associated with an increased severity of cartilage degeneration and radiographic osteoarthritis. In spite of distinct cartilage changes arthroscopic treatment improved knee-related symptoms at least on medium-term also in patients with degenerative meniscal tears. In this study, increased concentrations of the investigated MMPs did not seem to be associated with specific patterns of meniscal lesions.


E. E. Abdel Fatah M. R. Mahfouz

The success of TKAs depends on the restoration of correct knee alignment and proper implant sizing and placement. The mechanical axis is considered a key factor in the restoration of knee alignment along with the transepicondylar axis and the posterior condylar axis as references for external and internal implant rotation. Accurate calculation of the distal resection plane in the femur and proximal resection plane in the tibia is crucial to determine the amount of the bone to be resected. In this study, we developed a model for mapping the thickness of the femoral and tibial articulating cartilage. We also studied the effect of cartilage presence and the absence on the accuracy of calculating the surgical landmarks, implant sizing and placement.

Cartilage models were constructed using fat suppression MRI scans of healthy individuals with different body sizes. The femoral and tibial cartilages were segmented and surface models were generated. The inner and outer surfaces of the cartilage were separated, the inner surfaces were then mapped to the articulating surface of the femur and tibia to establish correspondence between the cortical bone surface and the inner surface of the cartilage. For each vertex on the normalized inner surface of the cartilage, the closest point was found on the outer surface of the cartilage and the normal distances were calculated. These distances were then averaged for each vertex across the population to calculate an average cartilage model. This average cartilage model was then used to grow a cartilage layer on our database of 300 bones from CT scans. Surgical landmarks and implant sizing and placement were then calculated for each bone before and after the cartilage and results were compared.

Some of the landmarks including the mechanical and transepicondylar axes were found to be independent from the presence or absence of knee articulating cartilage, whereas the posterior condylar axis and tibial and femoral resection planes can be affected by the absence or presence of cartilage.


W.G. Ward J. Cooper D. Lippert R. Kablawi R. Sherertz

Perioperative infections can cause devastating results, especially in cases employing endoprostheses and/or allografts. To minimize bacterial contamination and thereby decrease infection rates, a series of experiments was performed to determine the role of several factors on intraoperative contamination.

In an initial pilot study, 102 surgical team members participating in clean orthopaedic cases were prospectively randomized to exchange or not exchange their outer pair of gloves one hour into the surgical procedures. Rodac plate cultures of the surgeon’s dominant gloved hand and of his or her gown sleeve were taken at baseline and again 15 minutes after potential glove exchange. The surgical gown type (reusable cloth versus disposable paper) utilized in each case was recorded. An unexpected overwhelming effect of gown type on bacterial contamination rates was detected, which overpowered any effect of glove exchange. The outer glove exchange experiment was then repeated with 251 prospectively randomized surgical team members, with all team members utilizing only disposable paper gowns. Otherwise the experimental protocol was the same. A final experiment was devised to test bacterial strike through of the two gown types. A standardized suspension (3 ml of coagulase negative staphylococcus containing 108 bacteria/ml) was applied to one side of the test materials and compressed with a 10 lb. weight. A rodac culture plate was applied to the opposite side of the material to determine bacterial strike through rates utilizing previously validated methodology.

The initial pilot experiment revealed a baseline sleeve culture positive rate of 41% with cloth gowns versus only 13% with disposable gowns (p=0.002, Students t-test). Cultures of the glove one hour and fifteen minutes into the operations revealed a 31% culture positive rate with reusable cloth gowns versus only 7% with disposable gowns (p=0.001), with a 4.38 x odds ratio. There was no statistically significant difference in the glove culture positive rate at one hour and fifteen minutes based on glove exchange (19% with glove retention vs. 10% following glove exchange p=0.19). There was no statistically significant difference in the culture positive rate between the two gown types when tested straight out of their sterile packaging (reusable gowns two positive cultures out of 50 cultures, disposable gowns zero positive cultures out of 50 cultures). On the second glove exchange experiment, surgeons exchanging gloves one hour into the case had a positive glove contamination rate of 13% compared to 23% in those retaining their original glove (p=0.04 Student’s t-test, odds ratio 0.51). The bacterial strike through study revealed that 22 of 25 cloth gowns allowed transmission of bacteria, whereas only 1 of 25 disposable paper gowns allowed transmission of bacteria (p=0.001, nonparametric sign rank test).

The choice of gown type had the greatest effect on the intraoperative culture positive rate of the surgeon’s dominant hand glove in our studies. Based on these results, at our institution, all orthopaedic surgeons now utilize only disposable paper gowns on all cases employing allograft or endoprosthesis implantation. We strongly recommend that only disposable paper gowns be utilized for any case with any orthopaedic implant materials and such gowns should be considered for all surgical cases. Exchange of the surgeon’s outer gloves prior to handling orthopaedic implant devices, especially if an hour of operating time has already elapsed, is also a recommended and prudent practice to diminish intraoperative contamination of the implant materials. The utilization of disposable drapes in addition to disposable gowns is also recommended due to the lower likelihood of bacterial strike through with currently available disposable synthetic materials. Following these recommended guidelines should help surgeons minimize the risk of intraoperative contamination and should thereby reduce the rate of infections.


W. Wang H.S. Ong J.H. Hui

High tibial valgus osteotomy is now well established in management of medial knee osteoarthritis. While conventional closing osteotomies are usually within 2 cm of the knee joint, opening wedges typically pivot more distally from the joint line; theoretically the same angular correction will cause greater linear shift of the tibial plateau away from the tibial long axis. We hypothesise that this may lead to an increased incidence of problems with future knee replacement where tibial stem augments are needed, and to evaluate this we used a computerbased templating system with web-based component templates for sizing and implant position planning.

We studied 10 knees that had undergone opening wedge osteotomy. Pre-operative and postoperative mechanical and anatomical axes, and corrections achieved, were measured radiologically. Computer-based knee arthroplasty templating was then performed with the TraumaCad digital templating software (Orthocrat, Israel), using Depuy PFC tibial component templates with 75 mm stem augments. Cases were analysed for impingement of tibial stem augments when added to a well-placed tibial tray, and conversely for the need for tibial tray downsizing to avoid tray overhang if stem augments were placed centrally.

Results: Mean pre-operative mechanical axis was 10.6o varus (1.6o to 22.3o). Mean osteotomy to joint line distance was 25.7mm (21.0mm to 33.1mm). In four knees, the addition of a 75 mm tibial stem augment to a well-placed tibial component caused stem impingement on cortex. In these four cases, central placement of the stem augment in the canal led to medialisation of the tibial component, necessitating downsizing of tibial tray by one to two sizes to avoid medial overhang and resulting in sub-optimal coverage of the cut tibia. These four cases all had valgus corrections of over 11o (11.5o to 19.6o). Conversely the six cases that did not have impingement or sizing problems all had corrections under 9o (3.0o to 8.2o). Our early results suggest that higher degrees of valgus correction with opening wedge osteotomy may lead to problems with future knee replacements requiring tibial stem augments. We are in the process of recruiting more cases to determine threshold levels for different makes and models of implants, using the same templating software system.


N. Kitamura K. Arakaki H. Fujiki T. Kurokawa M. Iwamoto M. Ueno F. Kanaya Y. Osada J. P. Gong K. Yasuda

Development of artificial cartilage has been one of the future goals in the field of orthopaedic surgery. A few investigators have applied polyvinyl-alcohol hydrogel (single-network) to develop the artificial cartilage. However, it could not be applicable for clinical use due to insufficiency of the strength, the toughness, and the friction properties. The authors have conducted a fundamental study to apply a novel double-network (DN) hydrogel to develop the artificial cartilage. This hydrogel is composed of two independently crosslinked hydrophilic networks of poly-2-acrylamido-2-methyl-propanesulfonic acid (PAMPS) and poly-N,N′-Dimetyl acrylamide (PDMAAm) that are physically entangled with each other. This study evaluated the in vivo influence of a PAMPS/PDMAAm DN hydrogel on counterface cartilage in rabbit knee joints and its ex-vivo frictional properties on normal cartilage.

In the first experiment, the DN gel was implanted in a surgically created defect in the femoral trochlea of rabbit knee joints and the left knee was used as the control.

Evaluations using a confocal laser scanning microscopy demonstrated that the DN gel did not affect the surface microstructure (surface roughness, the number of small pits) of the counterface cartilage in vivo at 4 and 12 weeks. The histology also showed the DN gel had no pathological damage on the cartilage matrices and cells at 4 weeks.

However, 2 of the 5 DN gel-implanted knees showed mild irregularity on the counterface cartilage surface at 12 weeks. In the second experiment, the friction property between the normal and artificial cartilage was determined using a joint simulator apparatus. The ex-vivo mean friction coefficient of the DN gel to normal cartilage was 0.029, while that of the normal-to-normal cartilage articulation was 0.188. The coefficient of the DN gel-to-normal cartilage articulation was significantly lower that of the normal-to-normal cartilage articulation (p< 0.0001). This study suggested that the PAMPS/PDMAAm DN gel has very low friction coefficient on normal cartilage and has no significant detrimental effects on counterface cartilage in vivo, and can be a promising material to develop the artificial cartilage.


T. Pandorf R. Preuss

Ceramic hip components are known for their superior material properties concerning the invivo loading situation. In comparison to other commonly used materials, ceramics have a very low friction coefficient and a high fracture load. However, there are a few reported occasions of in-vivo fracture of ceramic ball heads.

An experimental set-up imitating the in-vivo loading situation is used to analyze different scenarios that may lead to the fracture of the ball heads, such as dynamic loading, edge loading and the metal taper condition. It will be shown that even the worst-case set-up does not lead to fracture loads if the interface between ceramic ball head and metal taper is clean and dry. In contrast, certain disturbances/impurities of this interface can cause a further reduction of the fracture load.

Ceramic ball heads made of pure alumina have been loaded until fracture under various conditions. The angle between the loading direction and the metal taper equals 35°, the ceramic ball is mounted in an alumina insert. Parameters under investigation were the inclination of the insert, the loading rate, and the condition of taper and ball head (contamination of the interface between taper and ball with adipose and osseous tissue; stripe wear on the outside of the ball head). Altogether 58 specimens (all alumina heads mounted on a titanium taper) have been tested, To resemble the position of the human acetabulum during walking and standing up, the inclination of the insert was chosen to differ between 45° (walking) and 80° (standing up). A variation of the loading speed is also tested, with a maximal speed in the range of the in-vivo loading rate (chosen parameters: 0,5 kN/sec and 25 kN/sec). For fabric samples, bovine femur (corticalis) and porcine adipose tissue were used.

All fractured ball heads were statistically analyzed regarding the appearance of fracture in general, the fracture origin, and the metal transfer in the cone of the ceramic ball head.

The behavior of the ball heads for the different scenarios shows a great variation: If the inclination of the insert equals 45°, it is not pos sible to break the ceramic ball head at all because of the high plastic deformation of the metal taper. In case of edge loading, the fracture load drops to 20 kN for 28-12/14 S ball heads and 36 kN for 28-12/14 L ball heads. The loading rate and the contamination of the interface between ball head and taper with adipose tissue have no measurable influence on this value.

The largest effect on the fracture load has a contamination with osseous tissue. The fracture load decreases to 32% compared to the value measured without the contamination.

A minimal fracture load of approximately 8 kN (KK 28-12/14 L) was measured.

Statistical analysis shows that the fracture load depends linearly on the stiffness of the system (ball heads 28-12/14 S). Because none of the other parts changes during the experiments, the cause of the change in stiffness is most likely due to a change of the friction coefficient between ball head and taper: A reduced stiffness indicates a lower friction coefficient which results in higher normal forces in the ball head and, therefore, leads to lower fracture loads. This theory is supported by numerical calculations.

The influence of edge loading and contamination of the interface between taper and ball with osseous tissue on the fracture load can be shown. If the insert has a high inclination angle, high bending forces are applied to the ball head amplifying the effect of edge loading.

It should be accentuated, that the minimum fracture load of a ball head without contamination of the interface is still twice as high as the maximum forces measured in-vivo.

Contamination with osseous tissue leads to a minimum fracture load of approximately eight times of the body weight, a value being close to the maximum forces ever measured invivo.

Therefore, diligence is recommended during the implantation of the ceramic hip components in order to avoid disturbances of this interface. Because the reduction of the stiffness results in a reduction of the fracture load, the lubrication of the taper should be avoided.


W.Y. Shon N.K. Jajodia H.H. Yun

The authors propose a manual measurement method for wear in total hip arthroplasty (PowerPoint method, PP-method) based on the well-known PowerPoint software. In addition, the accuracy and reproducibility of the devised method were quantified and compared with two methods previously described by Livermore and Dorr, and accuracies were determined at different degrees of wear. The 57 hips recruited were allocated to; Class 1 (retrieval series), Class 2 (clinical series), and Class 3 (a repeat film analysis series). The PP method was found to have good reproducibility and to better detect wear differences between classes. The devised method can be easily used for recording wear at follow-up visits, and could be used as a supplementary method when computerized methods cannot be employed.

Level of evidence: Diagnostic study, level –II


S. Macmull M.T.R Parratt G. Bentley J.A. Skinner R.W.J Carrington T.W.R Briggs

Autologous chondrocyte implantation (ACII) has been shown to have favourable results in the treatment of symptomatic chondral and osteochondral lesions. However, there are few reports on the outcomes of this technique in adolescents.

The aim was to assess functional outcome and pain relief in adolescents undergoing autologous chondrocyte implantation (ACI).

Thirty-one adolescent patients undergoing ACI or Matrix-assisted chondrocyte implantation (MACI) were identified from a larger prospective study. Mean age was 16.3 years (range 14 – 18) with a mean follow-up of 66.3 months (12–126 months).

There were 22 males and nine females. All patients were symptomatic; 30 had isolated lesions and one had multiple lesions. Patients were assessed pre and postoperatively using the Visual Analogue Score (VAS), the Stanmore/Bentley Functional Rating Score and the Modified Cincinnati Rating System.

The mean VAS improved from 5.8 pre-operatively to 2 post-operatively. The Stanmore/Bentley Functional Rating Score improved from 2.9 to 0.9 whilst the Modified Cincinnati Rating System improved from 49.8 pre-operatively to 81.3 postoperatively with 87% of patients achieving excellent or good results. All postoperative scores exhibited statistically significant improvement from pre-operative scores.

The results show that, in this particular group of patients, this procedure produces reduction in pain and a statistically significant improvement in function postoperatively. We strongly recommend this procedure in the management of adolescents with symptomatic chondral defects.


A. Meyer-Lindenberg M. Thomann A. Krause N. von der Höh D. Bormann T. Hassel H. Windhagen

Degradable implants made of magnesium alloys as osteosynthesis material for weight-bearing bone are at present a main research area. With regards to biocompatibility, a MA with 0.8 wt.

% Calcium (MgCa(0.8)) has been shown to possess advantageous qualities. Long-term investigations in animal models however, showed that the degradation rate of this magnesium alloy was relatively rapid and therefore the mechanical properties decreased early during the implantation period. An implant for osteosynthesis in weight-bearing bones however needs to exhibit adequate stability during the first few weeks of fracture healing. This cannot sufficiently be assured by the MgCa(0.8) alloy. It has been suggested in the literature, that the degradation rate of MA could be reduced using a fluoride coating. Therefore it was the aim of this study to investigate, whether the coating of degradable MA MgCa(0.8) implants with magnesium fluoride layer leads to decreased degradation rate and in consequence to an improvement of the mechanical properties using an animal model.

Extruded pins (2.5 mm x 25 mm) of MgCa(0.8) were produced. Twenty of these pins were coated with a fluoride layer by submerging the implants in a bath with 40% hydrofluoric acid. With this procedure, the pins were covered with a thin (150–200μm thickness) MgF2 layer. Coated and uncoated pins were intramedullary implanted into both tibiae of ten New Zealand White Rabbits. Three and six months after surgery five animals of each group were euthanized and the tibiae were explanted for further analysis. Micro-computed tomography (μCT) and scanning electron microscopy (SEM) were performed of the explanted pins. In order to investigate changes of the mechanical properties, 3-point bending tests were carried out with MgCa(0.8) pins at the initial state and with the explanted pins, with and without the fluoride layer at both times. In addition, the mass loss of the pins was determined. To evaluate the degradation process of the MgCa(0.8) pins with the MgF2 layer, micrographs and element analyses (EDX) were accomplished after the three point bending tests.

During the investigation period, the rabbits showed no signs of lameness or pain. The MgCa(0.8) alloy and the MgCa(0.8) alloy with the MgF2 layer showed significant differences regarding the mechanical properties in dependence of the implantation duration. Generally, the mechanical resistance decreases with increasing implantation time. The 3-point bending test showed, that the values of maximal force of the coated MgCa(0.8) implants after three month implantation duration were lower than those of the uncoated implants. After an implantation duration of six months, the values of maximal force of the implants coated with MgF2 were higher than those of the uncoated implants. Regarding the implant mass, the coated and uncoated MgCa(0.8) implants showed a loss of mass during the implantation period. The mass loss of the coated implants was only slightly lower. This difference was minor after three months and more obviously after six months. With μCT new endosteal bone formation could be seen close to all implants. A decrease of the cross section dimension could be demonstrated with μCT and SEM and changes of the surfaces due to pitting corrosion could be demonstrated in both the coated and uncoated MgCa(0.8) implants on the whole length, which was more obvious after six months. The micrographs showed corroded surfaces but not preferred corrosion on the grain boundaries. The element analysis showed a degradation layer on the implant surface, which was more bulky on implants after six month implantation duration. The mapping shows, that the fluoride molecules are clearly visible after three and six months around the margin of the implant.

With the results of this study it could be demonstrated, that the coating of the MgCa(0.8) implants with a flouride layer did not have a positive influence on the mechanical properties and the degradation rate of the implant in the bone. This leads to the conclusion that MgF2-coated MgCa(0.8) implants are also not suitable for osteosynthesis in weightbearing bones.


K.A. De Smet P. Campbell M. Van Orsouw K. Backers H.S. Gill

There have been many reports of metal ion levels measured in the bloodstream of patients after metal-on-metal hip replacement, and it is generally accepted that levels of cobalt (Co) and chromium (Cr) are elevated after these types of devices are implanted. However, it is not clear how to interpret these elevated levels; in particular what are the acceptable levels and what levels indicate that close monitoring of the patient is needed. Our aim was to establish the differences in metal ion levels between well functioning patients and those with clinical problems.

We measured serum Co and Cr levels (microgram’s per litre or μg/l) using inductively coupled plasma mass spectrometry with a well established collection protocol of all patients attending follow-up clinics. Our inclusion criteria for this study were all patients unilaterally implanted with a metal-on-metal hip resurfacing with no other metallic implant; patients were categorized as either A. Well Functioning or B. Clinically Problematic (pain, reduced function, reduced ROM, negative x-ray findings) and differences in ion levels between these two groups were examined. Well functioning patient data was only included if measurements were made more than 12 months post-operatively to avoid run-in wear levels. Abduction angle was also measured from x-rays of the pelvis, and the frontal plane coverage arc of each implanted cup calculated (De Haan JBJS[Br] 2008;90(10):1291–7). There were a total of 519 patients, with 358 in Group A and 161 in Group B; patients had a variety of devices with Birmingham Hip Resurfacing (64%) and Conserve Plus (29%) being the most commonly implanted. To establish a guideline upper ion level value for well functioning implants the upper 75th percentile values for Co and Cr levels for Group A patients having 15 mm or more coverage arc were calculated. The risk of having clinical problems was calculated as function of metal ion levels higher or lower than these upper limits.

The ion levels were significantly (Mann Whitney U p< 0.001) higher in Group B (mean [95% confidence intervals], Co 10.2 μg/l [5.9 to 14.5], Cr 10.3 μg/l [6.7 to 14.0]) compared to Group A (Co 2.3 μg/l [1.7 to 2.4], Cr 2.8 μg/l [2.3 to 3.4]). The well functioning upper limit for Co was 4.1 μg/l and for Cr was 5.2 μg/l. Metal ion levels greater than these upper limits were significantly (Chi-square p< 0.001) associated with the presence of clinical problems. The odds ratio for Co greater than 4.1 μg/l was 11.2 [95%CI 5.7 to 22.3] and that for Cr greater than 5.2 μg/l was 4.3 [95%CI 2.6 to 7.0].

There were significantly higher metal ion levels measured in patients with clinical problems after metal-on-metal hip resurfacing than those with well functioning hips. We have proposed upper acceptable limits for Co (4.1 μg/l) and Cr (5.2 μg/l) serum levels. Cobalt levels appear to be more reliable in predicting risk of clinical problems; levels greater than our proposed upper limit have 11 times the odds of developing clinical problems and patients with such levels should be followed closely.


F. Inori H. Ohashi M. Matsuuta Y. Okamoto Y. Okajima H. Tashima K. Kitano

Nowadays navigation system for THA is widespread and contributes to accurate cup installation as for cup abduction and anteversion angles. On the other hand, cup center position is very important to prevent leg length discrepancy and to acquire appropriate muscle tension especially for DDH cases. However planning and accuracy of cup center position was rarely mentioned when the efficacy of navigation systems were discussed. We therefore examined not only accuracy of cup angles, but also of cup center position in our image-free navigation system for DDH.

One hundred three THA operations were performed with using the image-free OrthoPilot hip navigation system (B. Braun Aesculap, Tuttlingen, Germany) between May 2006 and July 2008 by three experienced surgeons. In this system, we can measure the length between two different points marked by special pointer during surgery. Thus we pointed the upper rim of obturator foramen (this mark was estimated the lower tip of tear drop, and the bottom of reaming hole (this mark was estimated same height from cup center position) before cup installation and measured the vertical length between them(op length). After operation, we measured the vertical length from tear drop to cup center on the x-ray film (xp length), and compared these two values.

The average difference of two values were 6.41±4.17 mm ((op length)-(xp length)). Secondly we divided them into two groups, large error group (> 0.7mm) and small error group (< 0.6mm) and investigated the cause of large error. As result, large error was influenced by difference of surgeons, whereas not influenced by patient’s etiology and BMI.

By using image-free navigation system for DDH, we can plan the cup center position and install it within the error of 6.4mm. This will contribute to avoid a lot of hesitations during surgery. However surgeon’s skill and habitants have influence on this technique. We have to investigate this system and make effort to further improvement continuously.


B.E. Bierbaum D.M. Ward C.E. Robbins

Wear simulator studies suggest low wear rates of Alumina ceramic femoral heads with polyethylene total hip bearings. Short-term wear and clinical data of ceramic/highly crosslinked ultra-high molecular weight polyethylene (UHMWPE) couples are under reported in the literature. A retrospective review was performed to determine and compare the wear rate for hips implanted with an Alumina ceramic femoral head and X3® poly-ethylene insert to the acceptable polyethylene wear rate in the literature.

We evaluated 70 primary total hip replacements performed at one institution, by two surgeons, from February 2006 through June 2007. At a minimum 2 year follow-up, calculated annual wear for the ceramic/X3® polyethylene articulations showed a significant decrease compared to literature reports of 0.1mm/year or greater for conventional polyethylene.

Radiographic and clinical outcomes show no loose implants, dislocations, ceramic fractures or revision surgeries at last follow-up. These early findings suggest that ceramic/X3® bearing couples may serve as an acceptable choice for the younger, active patient.


M.N. Mavrogordato M. Taylor A.C. Taylor M. Browne

The Acoustic Emission (AE) technique has been described as possessing ‘many of the qualities of an ideal damage-monitoring technique’, and the technique has been used successfully in recent years to aid understanding of failure mechanisms and damage accumulation in bone cement during de-bonding of the cement-metal interface fatigue loading, pre-load cracking during polymerisation and to describe and locate damage within an entire stem construct. However, most investigations to date have been restricted to in-vitro testing using surface mounted sensors. Since acoustic signals are attenuated as they travel through a material and across interfaces, it is arguable that mounting the sensors on the bone surface to investigate damage mechanisms occurring within the bone cement layer is not ideal. However, since direct access to the bone cement layer is not readily available, the bone surface is often the only practical option for sensor positioning.

This study has investigated the potential for directly embedding AE sensors within the femoral stem itself. This enables a permanent bond between the sensor and structure of interest, allows closer proximity of the sensor to the region of interest, and eliminates potential complications and variability associated with fixing the sensor to the sample. Data is collected during in-vitro testing of nominal implanted constructs, and information from both embedded and externally mounted AE sensors are compared and corroborated by microComputed Tomography (micro-CT) images taken both before and after testing.

The use of multiple AE sensors permitted the location as well as the chronology of damage events to be obtained in real time and analysed without the need for test interruption or serial sectioning of the test samples. Parametric analysis of the AE signal characteristics enabled those events likely to be associated with cracking as opposed to interfacial rubbing or de-bonding to be differentiated and it was shown that the embedded sensors gave a closer corroboration to observed damage using micro-CT and were less affected by unwanted sources of noise.

The results of this study have significant implications for the use of AE in assessing the state of total hip replacement (THR) constructs both in-vitro and potentially in-vivo. Incorporating the sensors into the femoral stem during in-vitro testing allows for greater repeatability between tests since the sensors themselves do not need to be removed and re-attached to the specimen. To date, all in-vivo studies attempting to use the AE technique to monitor the condition of any replacement arthroplasty device have used externally mounted sensors and suffered from the attenuation of acoustic information through flesh and skin. It is hypothesised that the use of directly embedded AE sensors may provide the first steps towards an in-vivo, cost effective, user friendly, non-destructive system capable of continuously monitoring the condition of the implanted construct and locating the earliest incidences of damage initiation.


H. Iguchi N. Watanabe S. Murakami S. Hasegawa K. Tawada M. Yoshida M. Kobayashi Y. Nagaya H. Goto M. Nozaki T. Otsuka Y. Yoshida Y. Shibata Y. Taneda T. Hirade J. Fetto P.S. Walker

Introduction: For longer lasting and bone conserving cementless stem fixation, stable and physiological proximal load transfer from the stem to the canal should be one of the most essential factors. According to this understanding, we have been developing a custom stem system with lateral flare and an off-the-shelf (OTS) lateral flare stem system was added to the series. On the other hand, dysplastic hips are often understood that they have larger neck shaft angle as well as larger anteversion. In other words they are in the status called “coxa valga.” From this point of view we had been mainly using custom stems for the dysplastic cases before. After off-the-shelf lateral flare stem system; which is designed to have very high proximal fit and fill to normal femora; was added, we have been using 3D preoperative planning system to determine custom or OTS. Then in most of the cases, OTS stem were suitably selected. Our pilot study of virtual insertion of OTS lateral flare stem into 38 dysplastic femora has shown very tight fit in all 38 cases. The reason was analyzed that the excessive anteversion is twist of proximal part over the distal part and the proximal part has almost normal geometry. In the present study, 59 femora were examined by the 3D preoperative planning system how the excessive anteversion effect to the coxa valga status.

Materials and Methods: Fifty-nine femoral geometry data were examined by the 3D preoperative planning system. Thirty-three hip arithritis, 3 RA, 2 metastatic bone tumours, 5 AVN, 1 knee arthritis, 12 injuries, and 3 normal candidates were included. Among them one arthritic Caucasian and one AVN South American were included. The direction of the femoral landmarks; centre of femoral head (CFH), lesser trochanter (LTR), and asperas in 3 levels (just below LTR, upper 1/3, mid femur; A1-3); were assessed as the angle from knee posterior condylar (PC) line. Neck shaft angle of each case was assessed from the view perpendicular to PC line and neck shaft angle form the view perpendicular to CFH and femoral shaft (i.e. actual neck shaft angle).

Results: Average anteversion was 34.4 +/−9.9 degree. CFH and LTR correlated well (i.e. they rotate together). A1, A2, A3 correlated well (i.e. they rotate together). LTR and A1 correlate just a little, LTR and A2 were independent each other. So the twist existed around A1. Neck shaft angle was 138.7+/−6.6 in PC line view and in actual view 130.3+/−4.4. No excessive neck shaft angle was observed in actual view. Even the case that has the largest actual neck shaft angle (140.4), the virtual insertion showed good fit and fill with the lateral flare stem.

Conclusion: In many high anteversion cases, coxa valga is a product of the observation from non perpendicular direction to CFH-shaft plane. Selection or designation of the stem for high anteversion cases should be carefully determined by 3D observation.


S.D. Stulberg M. Yaffe D.C. Villacis

The trend toward evidence-based decision-making in orthopedics requires the analysis of large sets of data in real time that can direct clinical decision-making. We have developed an automated web-based electronic data capture (EDC) software system designed to simplify and make more time and cost efficient orthopedic data collection and analysis. The purpose of this study is to validate the radiographic alignment tool of the EDC software system. The goal was to establish the feasibility of using this web-based EDC tool in clinical practice.

Twenty-eight consecutive unilateral TKAs were performed on 28 patients. Coronal mechanical axis and sagittal tibial and femoral axis radiographic measurements were obtained preoperatively and 1 month postoperatively. The radiographs were uploaded to a web-based EDC knee surgery data analysis program that includes a radiographic measurement tool. Two blinded observers analyzed the radiographs; one using a conventional manual measurement tool and the other a web based measurement tool. A paired t-test was used to evaluate measurement variation between observers.

There was no statistically significant difference in pre-operative mechanical axis (.18°, p> .05), postoperative mechanical axis (.25°, p> .05), postoperative femoral component axis (.68°, p> .05), and postoperative tibial component axis (1.07°, p> .05) measurements performed using the manual tool and the web-based software systems.

The results of this study validate the ability of the web-based software system to collect and process radiographic measurements. An automated web-based EDC software system allows for the full integration of patient demographic, radiographic, and peri-operative clinical variables in a fully searchable, instantaneously updatable and easily analyzed database. It is anticipated that this unique approach will allow surgeons to gather a wealth of searchable and quantifiable data that can quickly, accurately, economically, and efficiently shape clinical decisions.


A. Moroni G. Micera R. Orsini M. Hoque S. Giannini

Although metal-on-metal hip resurfacing (MOMHR) is becoming a well accepted indication for young active patients with hip deformities, it does not come without its disadvantages. Longterm bone atrophy, serum metal ion elevation, metal ion hypersensitivity and the formation of pseudotumours have all been reported in the literature. It is thus clear that there is a need for novel bearing technology.

A potentially revolutionary hip resurfacing system comes in the form of the TriboFit® Hip System, which comprises a 2.7 mm-thick acetabular buffer made of polycarbonate-urethane, a hydrophilic, biocompatible, endotoxin-resistant material which mimics the fluid film layer naturally present in hip joints. This is a pliable implant whose modulus of elasticity is the same as that of normal human cartilage, thus providing optimum shock absorption. In addition, it induces lubrication, which is of the utmost importance as friction is almost eliminated, resulting in a subsequent decrease in the production of wear particles. Indeed, in vitro studies have shown that metal wear is 7-fold less than with a comparable metal-on-metal implant.

The TriboFit® Buffer is implanted using flexible mechanical fixation. With a special instrument, a circumferential groove is cut into the patients’ socket. The TriboFit® Buffer is seated by applying gentle pressure, with its ledge snapping tightly into the groove. The surgical technique is bone sparing as no acetabular bone reaming is required whatsoever. The TriboFit® Buffer can be coupled with a select number of metal hip resurfacing femoral components.

In our centre, we have used this novel bearing technology to treat patients with both osteoarthritis (two patients) and avascular necrosis (four patients). The mean patient age was 50 years (range 30 to 63). In five patients who had a well preserved socket anatomy, the TriboFit® Buffer was implanted without reaming the acetabular bone. In one patient with significant osteoarthritic changes of the socket, the TriboFit® Buffer was inserted into a specially manufactured uncemented metal shell, using the TriboFit® Buffer as a liner. The socket was reamed according to the standard reaming technique. In two patients a Birmingham hip resurfacing (BHR) femoral component was used and in the other four an ADEPT component was used.

Rehabilitation was fast and uncomplicated. The mean follow-up of these patients was one year. The mean preoperative Harris hip score (HHS) was 62. The mean HHS at one year was 99 (p = < 0.05). X-rays showed good quality bone at the bone-implant interface. No osteolysis, loosening, or bone rarefaction was observed. At follow-up, two patients resumed sporting activities. One patient resumed skiing while the other resumed biking.

Our pilot study shows that TriboFit® Buffer hip resurfacing arthroplasty is a valid alternative to MOMHR. Compared to the latter, the major advantage includes significantly lower metal wear generation, without any differences in the functional results. This new technology has the potential to expand the use of hip resurfacing to patients with renal malfunction, metal ion allergy/hypersensitivity and to fertile females.


Stephen Murphy James C Chow Kort Eckman Branislav Jaramaz

Introduction: Malposition of the pelvis at the time of acetabular component insertion can contribute to malpositioning of the acetabular component. This study measures the variation in intraoperative positioning of the pelvis on the operating table during surgery by matching intraoperative radiographs with pre-operative computed tomograms (CT) using 2D-3D matching.

Methods: This prospective study was comprised of a random sample of 45 patients (n = 45, 26 female, 19 male) who had received a total hip arthroplasty (THA) from a single surgeon from 10/21/2003 to 9/6/2007. No THA candidate was excluded for any reason, including body habitus (mean BMI = 27.7, range 17.5 – 42.3), underlying disease process, age (mean age at surgery = 57, range 27 – 80), sex or side of surgery (21 left THAs, 24 right THAs). According to our standard clinical treatment protocol, each patient had a pre-operative CT scan for CT-based surgical navigation of the hip arthroplasty and each patient had an intraoperative radiograph taken to assess component positioning. All THAs were performed in the lateral decubitus position on a radiolucent peg-board positioning device. Each patient’s intraoperative pelvic radiograph was taken after acetabular component and trial femoral component insertion with the leg placed in a neutral position on the operating table and with the xray plate aligned squarely with the operating table. The orientation of the pelvis on the operating table was calculated by comparing the intraoperative 2D projection to the 3D CT dataset using software that can perform 2D-3D matching (XAlign). This software has been validated previously. By matching the 3D CT dataset to the magnification and orientation of the plain radiograph, the position of the anterior pelvic plane relative to the operating table could be calculated.

Results: The mean pelvic tilt (rotation around the medial-lateral axis) was 6.84 degrees of anterior pelvic tilt (lordosis) with a standard deviation of 7.95 degrees and a range from 27.24 degrees of lordosis to 4.96 degrees of kyphosis. The mean pelvic obliquity (rotation around the longitudinal axis) was 2.89 degrees anterior from neutral with a standard deviation of 9.44 degrees and a range from 29.36 anterior to 16.59 posterior from neutral. The mean pelvic rotation (rotation around the anterior-posterior axis) was 2.56 degrees cephelad, with a standard deviation of 4.10 degrees and a range from 10.88 degrees cephalad to 5.97 degrees caudad. Pearson correlation statistics showed no relation among pelvic position and body mass index or age. A correlation was seen between pelvic obliquity and pelvic rotation.

Conclusion: This study shows a high variability of intraoperative pelvic positioning in the clinical setting using accurate measurement tools. The greatest variation was seen in pelvic obliquity which has the greatest influence on anteversion/retroversion of the acetabular component. Additionally, pelvic obliquity and rotation appear related in our series. Since all of our intraoperative radiographs were taken with the leg in a neutral position, it is likely that the pelvis is even more greatly malpositioned at other times during the surgery when forces applied by retractors or upon the leg may be greater.


B.H. Currier D.W. Van Citters A.J. Martin J.C. Huot J.H. Currier J.P. Collier

Irradiation cross-linking of UHMWPE has been shown to reduce wear while generating free radicals that oxidise in the presence of oxygen or oxidising species. Various methods have been used to minimise or eliminate the effect of these free radicals including below-melt annealing, remelting, Vitamin E infusion, or the use of other antioxidants. Each method has benefits and drawbacks with respect to wear properties, mechanical properties, and chemical properties. Accelerated aging techniques are used to evaluate the efficacy of new methods in stabilising free radicals in highly cross-linked UHMWPE.

Various procedures have been described for aging standard gamma-air sterilised UHMWPE to produce oxidation levels that represent shelf-aged bearings. An important factor in evaluating and comparing these aging techniques is validating that they reproduce the profile of oxidation (depth and magnitude) seen both in gamma-air, shelfaged polyethylene and in clinical retrievals. Moreover, the resulting oxidation level in the aged UHMWPE should predict the fatigue and/or wear damage seen in retrieved gamma-air inserts and liners.

The present study compared clinically relevant UHMWPE samples aged with ASTM 2003-00, (Method B: 70°C, 5 atm O2, 14 days) and a published lower temperature, lower oxygen-pressure environment (63° C, 3 atm O2, 28 days). Longer aging times (35 to 42 days) were also tested to examine oxidation rate and time to onset of mechanical degradation.

Both published methods result in oxidation of gamma-air and gamma-barrier sterilised polyethylene, but have little effect on remelted or antioxidant stabilised crosslinked polyethylene. These aging protocols, however, did not bring standard polyethylene to the critical oxidation level necessary for the fatigue damage that is seen in retrieved inserts and liners.

Oxidation of gamma-air and gamma-barrier sterilised UHMWPE increases exponentially with time on the shelf or in the two aging environments. Of note, longer aging times (35 to 42 days) that bring standard UHMWPE to sufficiently high oxidation levels for fatigue to occur also cause increased oxidation levels in remelted UHMWPE.

Oxidation increases were the smallest in antioxidant UHMWPE, though still detectable.

While this oxidation is not high enough in remelted material or antioxidant material to cause the fatigue damage seen in gamma-air sterilised UHMWPE, it does raise concerns about the published aging techniques and the long term stability of the new materials in vivo.

Relying on artificial aging techniques that do not adequately challenge even gamma-air polyethylene may conceal unforeseen weaknesses of new materials. Using longer aging times for existing techniques or novel aging approaches may be necessary to effectively evaluate the long term stability of new bearing materials.


J.N. Weisenburger S.M. Hovendick K.L. Garvin H. Haider

To eliminate UHMWPE debris, hard-on-hard bearing surfaces are regaining favor, and metal-on-metal (MOM) is one such combination. To further improve the performance of MOM THRs, a titanium nitride (TiN) coating is sometimes applied through pressure vapor deposition to femoral heads and acetabular liners. This coating has sufficient hardness and therefore may resist abrasion and reduce overall wear, or at least not prohibitively compromise them. One such coating applied commercially was tested on a hip simulator, with coated and uncoated (control) implants supplied by the same implant manufacturer. This study investigates the wear rates of MOM THRs with and without the TiN coating over a 5 million cycle (Mc) in vitro wear test.

Six MOM THRs with 44mm diameter CoCr femoral heads, acetabular liners, and acetabular shells were simultaneously tested on a hip simulator (AMTI, Boston). Three of the six had heads and liners coated in TiN, and the remaining three were uncoated for control. The specimens were mounted anatomically and were lubricated with bovine serum diluted with deionized water to have 20g/l protein concentration at 37°C. The THR specimens were subjected to the loading and rotations of the walking cycle in ISO-14242-1 at 1Hz for 5Mc, without distraction. The loading and rotations were continually observed to ensure consistency with the desired waveforms. The femoral heads and acetabular liners were carefully cleansed and gravimetrically weighed at standard intervals.

Over 5Mc, the uncoated heads displayed a wear rate of 1.84±0.18mg/Mc while the coated femoral heads wore at 4.37±2.01mg/Mc. Wear results were similar in the case of the uncoated and coated metal acetabular liners (1.35±0.11mg/Mc and 4.16±2.06mg/Mc, respectively). However, most interesting was the observation that all three TiN coated THR specimens displayed a loss of coating on both the head and liner in the articulating region. The area where the coating wore away increased in size as the test progressed. The higher wear observed on the coated specimens was due to the removal of the coating, and perhaps the coating particles causing third body wear (evidenced by numerous scratches on coated components). The loss of coating occurred early in the experiment (after only 0.25Mc) in the case of one specimen which caused severe scratching and high wear to that specimen. After this “breakaway wear” occurred, the wear on that specimen stabilized. The difference in wear between the coated and uncoated femoral heads was not statistically significant. The difference in wear between the two types of metal acetabular liners was not statistically significant until 3Mc, after which it became marginally significant (p< 0.05).

Our simulator results confirm small wear overall for MOM THRs, however, we did find extreme “run-in” wear on one TiN coated specimen. The eventual loss of the TiN coating on all three coated specimens is of concern, as this coating is marketed commercially in some parts of the world. It is possible that the coating process was conducted improperly, which resulted in poor adhesion to the substrate, or perhaps resulted in thin application/deposition in the area where the coating did not last.


A. Mullaji G.M. Shetty

Extensive release of postero-lateral structures may be required to correct rigid and severe valgus deformities during total knee arthroplasty. Current techniques are technically difficult, may not accurately restore soft tissue balance, and are associated with postoperative complications. We evaluated the results of using computer navigation for lateral epicondylar osteotomy during total knee arthroplasty for rigid severe valgus arthritis.

We had performed this procedure during navigated TKA in 10 valgus arthritic knees (2 bilateral TKAs) in 8 patients (1 male and 7 female). The mean age at the time of surgery was 65.7 years (range, 48–77 years) and the mean preoperative valgus deformity was 19.25° (range, 10°–36.5°). The mean postoperative limb alignment at the end of a mean follow-up of 20 months (range, 14–31 months) was 0.5° valgus (range, 2° varus–1.8° valgus). None of the patients had any complications related to the procedure with no obvious clinical mediolateral instability and complete union at the osteotomy site was noted in all patients radiographically at the last followup.

Computer navigation allows for precisely measuring the difference between medial and lateral gaps as well as the limb alignment and to determine the effect of sequential soft-tissue releases on both. Our technique takes advantage of this feature to accurately re-position the lateral epicondylar block in order to equalize medial and lateral gaps thereby ensuring a stable knee. Internal fixation with compression screws coupled with large contact surfaces of cancellous bone at the osteotomy site allow for early post-operative rehabilitation and ensure union at the osteotomy site.


E.R. Pritchard M.R. Mahfouz

Force profiles across the foot yield information on abnormal kinematics and may be used to indicate pathological changes in the lower limb. However, current technology is limited to tethered systems using wired sensors. This paper outlines a wireless prototype that allows force profile measurement and through an in-shoe monitoring device utilizing custom high-accuracy sensors.

Direct measurement of the ground reaction force using a force plate is common practice for use in kinematic studies and is used as an input for mathematical models to predict forces across joints of interest during various activities. Force plates are reasonably accurate but are bulky and only allow one net force measurement at a single location and are not portable. Thus natural patient motion may be modified, intentionally or unintentionally, in order for heelstrike to occur on the force plate. In addition to force magnitude, it is useful to record force location to correlate with kinematics; abnormal kinematics will cause weight-bearing forces to shift across the foot. Current in-shoe pressure measurement devices on the market are plagued by errors up to 30% and require a cumbersome cable out of the shoe to read sensor data. By eliminating all wires, our device enables in-shoe monitoring in a research or clinical environment.

The device uses microelectromechanical system (MEMS) capacitive pressure sensors fabricated in a flexible array that attaches to a shoe insole or orthotic. The sensors are concentrated at the heel and forefoot in the prototype design and they exhibit a highly linear response to loading, eliminating the need for constant recalibration. Electronics embedded in the shoe read the entire array of 256 sensors at a rate of 60 Hz. The data is transmitted via Bluetooth at 2.4 GHz to the receiving computer for visualization and analysis. The paper assesses current technology in in-shoe sensing, outlines the device design, and reports initial stages of testing.

The prototype developed in this study shows promise for wireless monitoring of ground reaction forces for biomechanics analysis without restricting activity or impeding natural motion.


G. To M.R. Mahfouz

Body motion tracking for kinematic study is typically done with optical sensors. The user wears markers and the cameras track them to compute the transformation of the motion frame by frame. This method requires a set up of multiple motion capturing cameras and it can only be done within the specific area. The goal of this project is to create a tracking unit that does not require expensive overhead and can be done in any location.

The advancement in micro-machined microelectromechanical system (MEMS) sensors such as accelerometer, gyroscope and magnetometers can be used for human motion tracking.

The unit is attached to a body segment or an external housing unit such as a knee brace. The orientation of the unit can be calculated based on the data from all 3 of the sensors. A complementary filter is used to fuse the data together to generate a single Euler angle matrix.

Relative motion between the joint can be calculated from the output of 2 of the measuring units.

The sensors are calibrated with an average static orientation error of +/−0.7 degree and standard deviation of 1.8 degrees. The dynamic orientation error of rotating around a single axis is 2.38, 0.15 and 0.517 degrees with standard deviation of 0.99, 0.98 and 0.7 degree for roll, pitch and yaw respectively.

The initial design shows good result for human body motion tracking. The performance of the unit can be further improved with optimizing the filter and using the data from different type of the sensors to compensate each other.


B. Masson J.Y. Lazennec J. Fisher L. Jenning

Dislocation remains one of the most common complications after total hip arthroplasty.

Precise cup position appears to be a main factor as significant variations occur for frontal and sagittal acetabular tilt and anteversion according to sitting or standing positions.

An innovative dual mobility ceramic-on-ceramic joint has been developed to solve these problems.

The dual mobility ceramic-on-ceramic joint allows to move the rotation center much deeper inside the insert in order to increase the joint stability without negative impact on the ROM. This device revealed higher torques against subluxation in comparison to the classical Al-Al systems, even with 36mm head diameters, or 41 mm metal on metal bearings.

The additional outer-bearing surface motion creates a second “adjustable acetabulum” due to the eccentration between the rotation center of the ball head and the rotation center of the bipolar head. This offset creates a resultant force that rotates the bipolar component.

Using two bearing ceramic surfaces, the intermediate component acts as a “self adjusting cup”, dealing with the variations of pelvic orientation and acetabulum anteversion.

The use of the dual mobility ceramic-on-ceramic joint seems an interesting alternative when facing difficult or unexpected situations for cup adjustment and cases with hip instability In a hip simulator in micro separation condition, the wear of the dual mobility ceramic-on-ceramic was less than 0.01 mm3/million cycles, the detection limit for wear measurement. There was no change in the surface roughness of the inserts.

The design of the joint with the mobile ceramic head prevented edge loading of the head on the edge of the cup. No stripe wear was observed.

Since 2006 more than 2000 dual mobility ceramic-on-ceramic systems have been implanted in Europe and clinical studies are conducted. The aim is to demonstrate the resistance to dislocation in primary total hip arthroplasty. Previous results over 125 patients in a prospective multicentric study show a Harris and Womac score equivalent to a standard hip prosthesis. No dislocations have been reported. No ceramic breakage or “squeaking” phenomenon appears.

Dislocation and microseparation are major causes of failure for ceramic-ceramic hip prosthesis. When no ideal solution has been found for acetabular implantation, the dual mobility ceramic-on-ceramic device is a real alternative. The exclusive design of the bipolar head give the high resistance to wear and stripe wear to the dual mobility ceramic-on-ceramic joint. Reducing the risk of dislocation and reducing wear drastically are two advantages that can place the dual mobility ceramic-on-ceramic joint as the best choice in primary Total Hip Arthroplasty. Obviously this choice applies to recurrent dislocation also.


K. Tawada H. Iguchi N. Tanaka N. Watanabe S. Hasegawa S. Murakami M. Kobayashi Y. Nagaya H. Goto M. Nozaki T. Otsuka

Canal Flare Index, defined as the ratio of the intracortical width of the femur at a point 20mm proximal to the lesser trochanter and at the canal isthmus by Noble et al,; is considered to express the proximal femoral geometory, but it is usually measured by a plain A-P X-ray. Then it is thought the index is influenced by rotational position of the femur, so we made 3-D femoral model based on CAT scans and measured the canal flare index three dimensionally. Then the effect of observation from rotated direction was evaluated.

CAT scans of 49 femurs (18 male, 31 female) were obtained from the pelvis to the feet. The average age was 60.4 years old ranging from 25 to 82. Forty nine femurs contained 22 osteoarthritis of hip joint, 12 trauma, 9 knee arthritis, 3 avascular necrosis of femoral head, 3 normal candetes. From those data, 3-D models of normal side were individually made for measuring the parameters. 3-D models were made using CAD software. We measured the canal flare index at which the femur posterior condyles were parallel to the plane, reproducing the situation to take A-P X-ray. After that, those 3-D models were rotated and investigated the difference of the value to study the effect of femur position.

The canal flare index was between 2.8 and 6.6 with the average value at 4.65. The stovepipe (canal flare index< 3), the normal range (3~canal flare index< 4.7), the champagne flute (4.7~canal flare index), included 2%(1 femur), 61.2%(30 femurs), 36.7%(18 femurs), respectively. About the effect of rotation, we found the value of canal flare index was more sensitive to proximal femur rotation than the canal isthmus. The results of the canal flare index at the plane parallel to the posterior condyle line varied widely compared with the results at the position considering the anteversion. So it was suggested that the canal flare index at the patella front position does not represent the canal characteristics. It should be argued in 3-D space.


C Pearce J Brooks S Kemp J Calder

Background: Foot injuries represent a small but important proportion of injuries to professional rugby union players. There are no detailed epidemiological studies regarding these injuries.

Purpose: The aim of this study was to describe the epidemiology of foot injuries sustained by a cohort of professional rugby union players and identify areas that may be targeted for injury prevention in the future.

Study design: Descriptive epidemiological study.

Methods: Medical personnel prospectively recorded injuries in professional, premiership rugby union players in England over 4 seasons. Injuries to the foot were identified and the time away from training and playing was reported.

Results: A total of 147-foot injuries were sustained resulting in 3,542 days of absence in total. Acute events accounted for 73% of all foot injuries, with chronic, mostly overuse conditions, accounting for 25% (undiagnosed 2%). Chronic conditions led to proportionately more time away from training and playing (p< 0.001). Specifically, stress fractures in the foot accounted for 8% of the total foot injuries but 22% of the absence. Navicular stress fractures had the longest recovery time with the mean return to training and match play of 188 days.

Conclusions: In collision sports, such as rugby, injury is inevitable, but clinicians should always be seeking ways to minimise their occurrence and impact. This study revealed significant morbidity associated with chronic and overuse foot injuries in these professional athletes. With greater attention paid to risk factors, some of these injuries, and importantly, recurrent injuries may be avoided.


C Tansey S Parsons J Hodkinson

Design: Retrospective chart and radiographic review.

Background: Stress fractures of the fifth metatarsal are increasingly common among elite professional footballers (soccer players). This reflects the use of lighter, less protective and more flexible sports footwear combined with the increasingly physical demands of the professional game at the highest level. Stress fractures of the fifth metatarsal can be satisfactorily treated non-operatively by cast immobilisation and a graduated return to activity. The demands placed on the modern elite professional footballer are such that a different treatment approach is required for the same injury in this subgroup of patients.

Methods: Stress fractures of the fifth metatarsal in elite professional footballers are treated by the senior author (JPH) by operative surgical fixation. We reviewed the charts and radiographs of all fifth metatarsal stress fractures that were treated operatively in elite professional footballers over a five year period. Details recorded included fracture location, method of fixation, complications, time to radiological union and time to return to independent weightbearing and competitive sporting activity.

Results: There were 32 fifth metatarsal stress fractures in 30 elite professional footballers. All fractures were clinically united at a mean 5.5 weeks and radiologically united at a mean of 10.3 weeks. The patients could weightbear immediately and could independently weightbear from 4 weeks. The mean time to return to full competitive activity was 10.3 weeks. There were no complications.

Conclusions: Operative treatment of fifth metatarsal stress fractures is an effective treatment in elite professional footballers that produces consistently good results and allows an early return to full activity.


M Suzangar P Rosenfeld

Background: The incidence of nerve injury following ankle arthroscopy has a documented rate of 1% to 24%1-15. The intermediate branch of the superficial peroneal nerve is at most risk with an antero-lateral portal incision 6, 9–12. The superficial peroneal nerve (SPN) is often marked as part of pre-operative planning,1 despite there being little evidence of the effectiveness of this simple measure in reducing nerve injury in ankle arthroscopies.

Methods: We reviewed 100 consecutive cases who had an anterior ankle arthroscopy between February 2005 and April 2009. All arthroscopies were performed by a single surgeon (PFR) with pre-operative marking of the SPN. All patients were interviewed by telephone to find out if there had been any temporary or long-term neurological problems following the surgery. Any patients with neurological complications were reviewed in clinic. Patients’ notes were reviewed for any documented complications. Their level of satisfaction and improvement of symptoms were also assessed.

Results: We were able to trace 98% of patients. The average follow up was 15.3 months (1 to 39 months). The only neurological deficit in this series was in one case (1%) who developed sensory loss in the distribution of the medial branch of the SPN. 61% of the cases were highly-satisfied/satisfied, 23% were moderately satisfied and 16% were not satisfied with the outcome of their surgery. The reason quoted by the 16% unsatisfied patients was failure to improve their symptoms to their expected level or their need for another operation (41% of the unsatisfied group)

Conclusion: The incidence of nerve injury in our series was 1%. This is a dramatic improvement on the majority of published studies 1–15. We believe that marking the SPN prior to surgery is a simple and essential measure in reducing the neurological complications of ankle arthroscopy.


N Meir H Ifthach M Gideon A Moshe

Background: The literature shows an anecdotal relationship between high-arched feet and proximal fifth metatarsal stress fractures. This relationship has never been supported by sound scientific evidence. Our aim in this study was to examine whether athletes sustaining this injury are characterized by a static foot structure or a dynamic loading pattern during stance.

Materials and Methods: Ten professional soccer players who regained full professional activity following a unilateral proximal fifth metatarsal stress fracture and ten control uninjured soccer players were examined. Independent variables included static evaluation of foot and arch structure, followed by dynamic plantar foot pressure evaluation during stance. Each variable was compared between injured and uninjured feet.

Results: Static measurements of foot and arch structure did not reveal differences among the groups. However, plantar pressure evaluation during stance revealed relative unloading of the fourth metatarsal in both the injured and sound limbs of injured athletes compared with control, while the fifth metatarsal revealed pressure reduction only in the injured limbs of injured athletes.

Conclusion: Athletes who sustain proximal fifth metatarsal stress fracture are not characterized by an exceptional static foot structure. Dynamically lateral metatarsal unloading during the stance phase may either play a role in the pathogenesis of the injury, or alternatively represent an adaptive process.

Clinical Relevance: Footwear fabrication for previously injured athletes should not categorically address cushioning properties designed for high-arch feet, but rather focus on individual dynamic evaluation of forefoot loading, with less attention applied to static foot and arch characteristics.


MJ Oddy S Jones MJ Flowers MB Davies CM Blundell

Introduction: The assessment of quality in the provision of healthcare is one of the core features of the National Health Service in the 21st Century. From April 2009 Patient Reported Outcome Measure (PROM) data are being collected for the Department of Health for elective hip and knee arthroplasty using generic and disease specific measures of health status. The perceived uses of these data may be for research, assessment of procedural outcome, measures of health inequalities and to aid commissioning groups in selecting their secondary care providers. Foot and ankle surgery covers a wide spectrum of operative procedures with patient responses less predictable than with major joint arthroplasty. We report the use of a sixteen point satisfaction-based questionnaire in order to investigate the nature of patient outcome after the processes of foot and ankle surgery.

Methods: A prospective series of 100 two-part Visual Analogue Scale (VAS) questionnaires was distributed to patients undergoing elective foot and ankle surgery at the Northern General Hospital under the care of four foot and ankle surgeons over a three-month period. The questionnaires were numbered to allow patient anonymity. The first part of nine questions enquired about pre-operative preparation and information and was distributed before surgery. The second part of seven questions, distributed at the first post-operative clinic sought to investigate their hospital and operative experience. Free text comments were requested in addition to the VAS responses, which were expressed as percentages.

Results: 97% of part one and 85% of part two questionnaires were returned completed. 82% had both parts completed and matched. The day case to inpatient ratio was 55: 45. For part one, all clinically related questions scored more than 90% satisfaction, with only two scores for administration-based questions falling below this level. For part two, satisfaction for clinical questions again scored more than 90% and overall, all scored more than 80% satisfaction. Only 23% of pre-operative and 28% of post-operative questionnaires were returned with free-text comments.

Conclusions: A simple patient satisfaction-based questionnaire may be as useful as existing non-validated generic scoring systems used in foot and ankle surgery when assessing quality in the health service, particularly where regional demographics or referral patterns may be important factors influencing patient outcomes. Active dialogue with the surgical colleges and Department of Health should be pursued to avoid inappropriate outcome measures being imposed in foot and ankle surgery.


N Sandiford S Weitzel

Introduction: Arthroscopic management of posterior ankle impingement syndrome (PAIS) is now commonly practiced. Scanty information about the results of this procedure in a district hospitals is available.

Aim: We present the results of our series of patients treated with hindfoot arthroscopy for PAIS, and describe the complications encountered.

Patients and Method: Twenty procedures were performed on 19 patients (12 males, 7 females) between January 2006 and September 2008. Patients were followed up for an average of 7.9 months. Return to sport, patient satisfaction, relief of symptoms and the American Orthopaedic Foot and Ankle Society (AOFAS) hind-foot score were all assessed.

Results: Procedures performed included excision of an os trigonum, flexor hallucis longus decompression, and microfracture of the posterior talus. The average age of the patients was 35 years. Return to activity occurred at an average of 4 weeks. Four patients were dissatisfied, 1 was unsure and all the other patients were satisfied with their outcome. The average pre-operative AOFAS score was 73.8 and the post operative score was 84.5. There were no neurovascular injuries.

Conclusion: There was a significant incidence of dissatisfied patients in the absence of major complications. This might reflect technical difficulties early in the early learning curve for this procedure.


A Abbassian J Kohls-Gatzoulis M Solan

Background: Isolated Gastrocnemius contracture has been implicated as the cause of a number of foot and ankle conditions. Plantar Fasciitis (PF) is one such condition that can be secondary to altered foot biomechanics as a result of gastrocnemius contracture. We perform an isolated proximal medial head of gastrocnemius release (PMGR) as a day-case procedure. This is to report our results of this procedure in the treatment of recalcitrant PF.

Material and Methods: We prospectively followed a consecutive series of 22 heels in 18 patients following a PMGR. To be included, at least one year of conservative treatment must have been tried and isolated Gastrocnemius contracture confirmed clinically using Silfverskiold’s test pre-operatively. Outcome measures included the visual analogue pain score (VAS) and a 5-point Likert scale of postoperative success. Subjective and objective calf weakness was also evaluated. Final follow up was at an average of 25 months (range: 12 to 36 months) after the surgery.

Results: Two patients were lost to follow up. In the remaining 20 heels the average VAS for pain had improved from 9.4 to 1.8 (P< 0.001). Fourteen heels (70%) were pain free or significantly better at final follow up. There was no objective evidence of calf weakness and only one patient (5%) felt subjectively weaker on the released side. There were no ‘major’ complications and only 2 cases (10%) suffered a ‘minor’ complication. One was a case of superficial wound sepsis and the other was of prolonged calf pain following the surgery. Both resolved spontaneously and without further intervention.

Conclusions: A PMGR is a simple way of treating patients with PF who fail to respond to conservative management. The results, in our series, have been favorable and the morbidity low. We recommend the use of gastrocnemius release once non-operative management has failed.


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JL Barrie P Taylor

Introduction: Coding systems are important for epidemiology, research, audit, activity analysis and now remuneration. There have been concerns that the existing coding systems do not represent foot and ankle activity accurately.

Materials and Methods: The senior author’s logbook was analysed for 2 years. Each operation descriptor was recorded. A “simple descriptor” described an operation of one component (“scarf osteotomy”). A “multiple descriptor” described multiple instances of one component (“bilateral scarf osteotomy”). A “compound descriptor” described a procedure made up of more than one component (“scarf osteotomy and 2nd toe straightening”). We encoded the logbook using OPCS4.5 and the RCSED Electronic Logbook. We assessed whether simple descriptors could be coded unambiguously (ie there was a one-to-one relationship between descriptor and code so that distinct procedures could be identified) and whether compound descriptors contained ambiguous codes. We also considered whether the overall procedure was adequately summarised by the tabulated codes. Codes were converted to the HRG4 and BUPA payment codes and referenced to chevron osteotomy.

Results: There were 513 procedures with 157 different descriptors (3.27 cases/descriptor, compared with 4.44 in upper limb and 7.69 in lower limb). Fifty-four descriptors (321 patients) were simple, 18 (52 patients) were multiple and 85 (140 patients) were compound. Using OPCS, 57.4% of simple descriptors (46.1% of patients) were ambiguous, as were 82.4% of compound descriptors (85.7% of patients). In 27.1% of descriptors (33.6% of patients) the tabulated codes did not give the overall procedure clearly. Using the eLogbook, 48.1% of simple descriptors (25.2% of patients) and 74.1% of complex descriptors (70.7% of patients) were ambiguous and in 30.6% of descriptors (37.1% of patients) the codes did not summarise the operation well. Most remuneration compared reasonably with chevron osteotomy, with some idiosyncrasies. Overall remuneration was lower than procedures of comparable complexity in other specialties.


R Walton A Theodorides A Molloy D Melling

Introduction: A learning curve is a recognised phenomenon in surgery. It implies that the frequency of peri-operative adverse events will decrease with the increase in experience of the surgeon. Evidence shows increased instruction and experience in a specific surgical task leads to improved performance. There is conflicting evidence as to whether there is a learning curve for total ankle replacement, and a paucity of evidence for foot and ankle surgery as a whole. Current evidence is centered on perioperative complications, rather than functional outcome.

Aim: To determine whether a learning curve effect is present during the first year of independent practice by measuring patient outcome.

Materials and Methods: 150 patients underwent elective foot or ankle surgery during the first 12 months of a newly appointed consultant’s practice. Preoperative and six month postoperative functional scores were recorded, together with perioperative complications. Two patients died of unrelated causes in the first 12 months. 121 patients (81.8%) were followed up for a minimum of six months by telephone. Functional outcome was assessed with a modified American Orthopaedic Foot and Ankle Society midfoot Score (85 points). Outcome was compared between the first and second six-month periods using the student’s t-test.

Results: Eighty procedures were undertaken during the first six months compared to 70 in the second. Total ankle replacements were only undertaken in the latter period. Otherwise there was no statistical difference in the caseload. One wound infection occurred during each period and other perioperative complications were equivalent. Functional improvement was greater in the group from the second 6 months (+23.86 v’s +18.69). This difference did not reach statistical significance (p = 0.061).

Discussion and Conclusion: There is a trend, approaching significance, towards a learning curve during a foot and ankle consultant surgeon’s first year of practice. Collating data from other new consultants may demonstrate a learning curve with statistical significance.


S Jameson P James K Oliver D Townshend M Reed

Background: Diagnostic and operative codes are routinely collected on every patient admitted to National Health Service (NHS) hospitals in England and Wales (hospital episode statistics, HES). The data allows for linkage of post-operative complications and primary operative procedures, even when patients are re-admitted following a successful discharge. Morbidity and mortality data on foot and ankle surgery (F& A) has not previously been available in large numbers for NHS patients.

Methods: All HES data for a 44-month period prior to August 2008 was analysed and divided into four groups – hindfoot fusion, ankle fracture surgery, ankle replacement and a control group. The control group was of first metatarsal osteotomy, which is predominantly day case surgery where no above ankle cast is used. The incidence of pulmonary embolism (PE) and all cause mortality (MR) within 90 days, and a return to theatre (RTT, as a complication of the index procedure) within 30 days was calculated for each group.

Results: 7448 patients underwent a hindfoot fusion. PE, RTT and MR were 0.11%, 0.11% and 0.12% respectively. 58732 patients had operative fixation of an ankle fracture. PE, RTT and MR were 0.16%, 0.08% and 0.35%. 1695 patients had an ankle replacement. PE, RTT and MR were 0.06%, 0.35% and zero. 35206 patients underwent a first metatarsal osteotomy. PE, RTT and mortality rates were 0.02%, 0.01% and 0.03%.

Discussion: There is controversy regarding the use of venous thrombo-embolic (VTE) prophylaxis in foot and ankle surgery. Non-fatal PE in F& A surgery has previously been reported as 0.15%. NICE guidelines recommend low molecular weight heparin (LMWH) for all inpatient orthopaedic surgery. 94% of F& A surgeons prescribe LMWH to post operative elective inpatients in plaster according to a previous British Orthopaedic foot and ankle society survey. VTE events, RTT and mortality rates for all groups were extremely low, including inpatient procedures requiring prolonged immobilisation. We question the widespread use of LMWH.


R Pradhan PF Rosenfeld

Background: Complex tibiotalar (TT) and tibiotalocalcaneal (TTC) fusions are performed for significant ankle and hindfoot arthritis and/or deformity. Literature suggests several methods of fixation including crossed screws, plates, nail and external fixation. These are technically difficult operations with reported complication rates as high as 30–80%. We present a retrospective cohort study of angle blade plate and PHILOS plate fixation for these patients in our hospital.

Methods: This study describes 21 consecutive patients with 22 TT or TTC fusions between December 2005 and May 2009. The surgery was performed for severe deformity or arthritis as a result of: osteoarthritis(2), post-traumatic arthritis(4), rheumatoid arthritis (7), Charcot arthropathy (5), avascular necrosis(1), and post traumatic avascular necrosis (3). The senior author performed all of the operations. In the first ten cases (two TT and eight TTC) an angle blade plate was used, A PHILOS plate was used in the subsequent ten cases (three TT and seven TTC). One patient had bilateral TTC fusions with a blade plate on one side and a PHILOS plate on the other. There were eight male and 13 female patients. All the procedures were performed through a lateral transfibular approach. The patients were followed up regularly with clinical and radiological evaluation until union or otherwise.

Results: Fusion was achieved in 19 out of 21 patients (90.5%) and 20 out of 22 arthrodeses (90.9%). All five TT fusions went on to union (100%). Fifteen out of 17 TTC fusions united (88.2%). One TTC fusion using an angle blade plate needed revision surgery for non-union of subtalar joint. In the PHILOS group one patient developed MRSA infection of the surgical site leading to non-union. This necessiated removal of metal and prolonged treatment with intravenous antibiotics. The patient now has a relatively painless fibrous ankylosis.

Conclusion: TT and TTC fusions are complex operations performed for severe arthritis and deformity, often on patients with significant co-morbidities. It is a salvage procedure to relieve pain and/or correct deformity of the foot and ankle. This study suggests that both the angle blade plate and PHILOS plate provide a stable fixed angle construct, which achieves a high rate of bony union with alignment correction.


L Hajipour PE Allen

Introduction: Non-union occurs at a rate of 5–10 % following ankle and hindfoot arthrodesis, but the effect of early weight bearing on union rate in these patients has not been studied.

Materials and Method: We have looked at the union rate following ankle and hindfoot arthrodesis with an early weight bearing protocol in a single surgeon series between 2003 and 2008. Data was collected retrospectively on 108 patients with a total of 198 ankle and hindfoot joint arthrodesis.

Results: The non-union rate was 3.4% (9 in 154 joints) in the early weight bearing group and 18% (8 in 44 joints) in the late weight-bearing group. Union rate following revision surgery with bone graft was 100% in both groups.

Discussion: Early weight bearing following ankle and hind-foot arthrodesis has no adverse effect on the union rate.


J Attard D Singh N Cullen E Gemmell D Cooper K Smith

Background: Non-operative treatment for plantar fasciitis varies widely and includes the use of night ankle-foot orthoses (AFO’s). Some studies have shown that this is more effective in the initial management of plantar fasciitis than anti-inflammatory therapy. During sleep the foot and ankle tend to assume a plantarflexed position, which results in tightness of the calf muscle group, accounting for the stiffness and pain experienced by patients as they take their first weight bearing steps in the morning. However, when the foot and ankle are kept in a dorsiflexed stretched position at night, stress relaxation occurs and the plantar fascia relaxes.

Aim: Compliance with night AFO’s that dorsiflex the foot/ankle has always been a problem. This study compares the effectiveness of a posterior AFO, which dorsiflexes the foot, with an anterior AFO, which maintains the foot in plantigrade, asking whether it is absolutely necessary to dorsiflex the foot and ankle during the night to avoid early morning pain and stiffness, or whether it is it sufficient just to maintain the foot in plantigrade.

Methods: 18 participants were recruited on a voluntary basis and at random from among those patients referred to the Orthotics department with plantar fasciitis to be provided with a night orthosis. The inclusion criterion was that the diagnosis was purely plantar fasciitis with no secondary diagnosis, symptoms or complications. Each participant was given a questionnaire to fill in; this evaluated how satisfied the participants were with the orthosis with regards to comfort, ease of use and appearance, and whether the pain in the foot was reduced and at what stage was it reduced. The two types of AFO’s used in this study were:

A posterior AFO that holds the foot in dorsiflexion. The amount of dorsiflexion could be adjusted.

An anterior AFO that keeps the ankle and foot in plantigrade, with no adjustment to the amount of dorsiflexion.

Results: 67% of the participants confirmed that morning pain and stiffness was less after wearing the AFO; this included 78% of those that wore the anterior AFO and 56% of those that used the posterior orthosis. 56% of all participants reported that the orthoses were uncomfortable and disrupted sleep. The most uncomfortable was the posterior AFO (89%), as opposed to the anterior one (22%). Both types of orthoses were reported to be relatively easy to don and doff (89% anterior AFO and 78% posterior AFO). On a scale of 1 to 10, the participants were asked to grade the pain before starting the orthosis treatment regime, after 6 weeks of wearing the AFO and again 6 weeks later. On average, the anterior AFO reduced the pain from 7 to 2.1, while the posterior orthosis only reduced the pain from 8.1 to 6.7.

Conclusion: In general, plantar fasciitis night AFO’s are poorly tolerated orthoses, however, their use can be justified in that the pain levels are reduced. The anterior AFO seems to be more effective in achieving this, without dorsiflexing the foot/ankle beyond plantigrade. Thus, one could argue that there is no need to dorsiflex to achieve the goal. However, further investigation is necessary with a larger patient cohort.


M Butler S Dheerendra NJ Goddard A Goldberg RJ Sharp NJ Ward PH Cooke

Introduction: Severe haemophilia affects 1 in 10,000 men. The ankle along with the hip and knee are commonly affected. Ankle fusion is the preferred surgery for end stage arthritis in the younger patient although debate exists as to the preferred technique. We conducted a retrospective review of the arthroscopic ankle fusions on haemophiliacs from Oxford and compared data with that of a specialist unit in London using an open technique.

Materials and Methods: We reviewed 22 ankles (22 patients) from Oxford and 10 ankles (8 patients) from London. 90% had Type A haemophilia with similar regular monthly Factor VIII usage: 17941 U/month (Oxford) compared with 17992 (London). 73% of patients in the Oxford Group and 100% of the London group had Hepatitis C and/or HIV.

Results: Union was achieved in all patients. The mean time to union in the open group was 9.1 weeks (Mode- 8 weeks, Range 7–14) compared to 12.2 weeks (Mode- 12 weeks, Range 8–24) in the arthroscopic group. Screw removal was required in 4 patients (3 arthroscopic v’s 1 open). 1 patient in the arthroscopic group suffered a pseudoaneurysm of the dorsalis pedis artery. The arthroscopic group spent less time in hospital- 5.7 days compared to 9.5. Factor VIII usage was less in the arthroscopic group- 32,882 Units compared to 40013.

Discussion: Patients of this nature should be managed in centres used to dealing with their complex needs. Arthroscopic ankle fusion in haemophiliacs is safe for these patients. Although arthroscopic fusion may take slightly longer to unite, there are benefits in terms of reduced patient stay and factor VIII requirement and therefore costs.


P Hamilton J Piper-Smith S Singh Jones

Introduction: Since the introduction of payment by results in the NHS in 2004, the accurate recording of services performed has played a crucial role in reimbursement to hospital trusts by primary care trusts (PCT). Failure to accurately charge for these services causes a shortfall in funding received. Under the new reimbursement system, similar treatments are grouped together under the same tariff and referred to as a Healthcare Resource Group (HRG). Coding is the assignment of procedures to HRG’s. We aim to assess the accuracy of coding performed at our institution and link this directly to the funds received from the PCT. Foot and ankle surgery has a particular interest in coding due to the multiple codes that are utilised to code for one procedure.

Method: We looked at 40 consecutive operations performed at our institution. We compared the codes assigned by the surgeon placing the patient on the waiting list, which were the codes seen directly on the operating list with the final codes given to the PCT. We compared the two codes and looked at the difference in final costing.

Results: There were a total of 75 codes from the 40 operations assigned by the surgeon compared with 103 codes assigned by the coding staff. Although most of the codes were different when the final costing data was generated there was little difference in the overall costs.

Discussion: The importance of accurate coding has become paramount in the current national health service funding. We have shown large discrepancies between the codes the surgeon produces and the final code given to the PCT. Although, in our unit, this has not led to differing final reimbursement figures, it does have the potential to create inaccuracies with a failure to pay for work performed. We will present our data and describe the correct coding for common procedures in foot and ankle surgery, to allow accurate reimbursement.


M Dunning H Taylor

Introduction: The HRG 4 coding system was introduced in April 2009 to allow the calculation of tariffs for all surgical procedures. At our institution we felt surgeon input could improve the accuracy of this coding and optimise trust income.

Method: A retrospective audit of one month’s procedures under the care of a single consultant was performed. The hospitals coding and tariff, as performed by coding clerks, was reviewed and the procedures were re-coded by a foot and ankle fellow using the notes and the HRG 4 grouper. A comparison was made between the coding and income generated in the standard fashion and that achieved after optimisation by surgeon input.

Results: The codes of 51 patients were examined. 86% of major foot procedures were correctly coded. However, 56% of ‘minor’ procedures were recoded as ‘intermediate’, many of these involving hallux valgus surgery. 58% of procedures had a different code after surgeon input and 41% generated a different tariff. The total tariff for the coding clerk group was £79,192. The total tariff in the surgeon assessed group was £97,268 - a difference of £18,076. Extrapolated over the year this could represent a potential gain of over £200,000, for a single Consultant in a single Trust.

Conclusion: We believe surgeon involvement in coding is crucial to improve accuracy and to optimise trust income. We will discuss various issues surrounding the new HRG 4 codes and how best to use them in current practice.


M Day CJ Topliss

Introduction: With increasing availability of CT scans their use in the investigation of the subtalar joint increases, whilst we continue to use plain x-ray. Using a standardised reporting protocol, we graded x-rays and CT scans to compare the diagnosis made using each modality.

Materials and Methods: An atlas and reporting system of the subtalar joint was designed using a modification of Kellgren and Lawrence’s system. 50 consecutive CT scans of the subtalar joint were identified and saved along with paired plain x-rays of the foot and ankle. All investigations were anonymised. Scans were excluded if there were no plain films or there was evidence of previous trauma. Orthopaedic surgeons were asked to report on the 50 CT scans and 50 plain radiographs using the reporting protocol, commenting on two components for each investigation; the anterior and middle facets and the posterior facet of the subtalar joint.

Results: In 33% of cases the facets of the subtalar joint could not be appreciated from the plain x-rays. The difference between the modalities in reported grade of degeneration of the anterior and middle facets of the subtalar joint was statistically significant (p= 0.014) but not for the posterior facet (0.726). When looking at the Spearman correlation coefficient, the anterior and middle facets had no correlation (r = − 0.067) although the posterior facet did (r = 0.029).

Discussion: When looking at the posterior facet of the subtalar joint plain x-rays and CT scans give comparable results. When looking at the anterior and middle facets the information gained from the plain x-rays bears no resemblance to that gained from the CT scans.

Conclusion: The plain x-ray is an inaccurate, unreliable method of investigating degenerate pathology of the subtalar joint and should be superseded, and perhaps replaced, by the CT scan.


D Townshend R Refaie B Lovell

Introduction: Thromboprophylaxis in Orthopaedic practice has long been a debated issue. The recent NICE guidelines have recommended low molecular weight heparins (LMWH) for all orthopaedic patients, although a number of authors have highlighted the low risk of thromboembolism in foot and ankle practice. We looked at our series of total ankle replacements (TAR) to identify the incidence of thromboembolism and any complications associated with chemical thromboprophylaxis.

Methods: All patients who had undergone TAR were reviewed retrospectively. Risk factors according to the NICE guidelines were identified as was the type of chemical thromboprophylaxis, if given. Complications including thromboembolism, wound ooze, swelling and delay in discharge were recorded.

Results: There were 45 TAR’s in 45 patients. 20 patients (44%) had been given some form of chemical thromboprophylaxis. There were no cases of thromboembolism in either group. In the group receiving chemical thromboprophylaxis, nine patients (45%) had a wound complication. In the group receiving no chemical thromboprophylaxis only one patient (4%) had a wound complication.

Discussion: Thromboprophylaxis in total ankle replacement may significantly increase the risk of wound complications. We would recommend caution when prescribing chemical prophylaxis for patients undergoing total ankle replacement.


EJ Baird QA Fogg RAE Clayton C Sentil Kumar P Patterson

Introduction: The sural nerve is commonly encountered in many operations on the lateral part of the foot and ankle, such as fixation of distal fibula, 5th metatarsal and calcaneal fractures, and fusion of the subtalar or calcaneo-cuboid joints. However there is no consensus and quantitative description of the branches of sural nerve distal to the ankle in the reviewed literature. This study aims to describe these branches and quantify their relations.

Methods: The distal course of the sural nerve was dissected in 30 embalmed cadaveric limbs.

Results: A fibular branch was found in close proximity to the tip of the distal fibula in 63% of specimens. A dorsal branch at the level of the cuboid was found in 80% of specimens, however, its point of departure from the main nerve varied considerably. More distally a series of plantar branches of varying number, and at varying distances to each other was found. These branches were then described in relation to the following bony landmarks: the tip of the distal fibula, the calcaneo-cuboid joint, the tuberosity of the base the 5th metatarsal, the shaft of the metatarsal and the 5th metatarso-phalangeal joint. The distances between these landmarks were quantified using digital analysis.

Conclusion: The sural nerve has a number of previously undescribed but potentially important branches distal to lateral malleolus in the foot. Identifying these branches during surgery with relation to the various bony structures should minimise the risk of nerve injury.


C Pearce R Elliot C Seifert J Calder

Introduction: Adequately managing post-operative pain following ankle and hindfoot surgery can be difficult. Conventional analgesics have significant side effects including nausea and gastric irritation. The results of a pilot study of continuous infusion v’s single bolus popliteal block encouraged us to perform the full PRCT.

Method: The trial was approved by the local Research and Ethics Committee and registered with the European Clinical Trials Database. Approval was obtained from the Medicines and Healthcare products Regulatory Authority (MHRA) for the use of normal saline infusion as a placebo. The recommendations of Good Clinical Practice in the conduct of clinical trials on medicinal products for human use were respected.

Inclusion criteria were all patients who were undergoing significant hind foot or ankle procedures. Exclusion criteria included coexisting peripheral neuropathy and any inability to fill in the questionnaire.

The pilot study provided a standard deviation of pain scores which allowed us to calculate the sample size required; 25 patients in each group would have 90% power to detect a difference in means VAS scores of 3 which we considered to be clinically significant. A total number of 56 (to allow for 10% loss to follow-up) were recruited. The patients and the assessors were blinded to the treatment allocated. Sealed envelopes contained random allocations and were opened by the anaesthetist. A bolus of 20ml 0.25% bupivacaine was injected and then the catheter was inserted and connected to a pump. Patients were randomly assigned to receive either an infusion of normal saline or bupivacaine over the next 72 hours.

The patients were asked to complete a visual analogue pain chart, three times daily, for 72 hours postoperatively. Data was also recorded regarding supplementary opiate analgesic requirements and any problems or complications.

Statistical analysis was performed using MedCalc for Windows, version 9.6.4 (MedCalc software, Mariakerke, Belgium). A Mann-Whitney U test was used for the non-parametric data sets.

Results: Both groups had very low median VAS pain scores on the day of operation and there was no difference between the two; study 1.167, control 1.000 (p=0.893). On the 3 post operative days studied there were significantly lower pain scores in the study group; day 1: 1.67 v’s 3.67 (p=0.003), day 2: 1.33 v’s 2.83 (p=< 0.001), day 3: 1.11 v’s 2.56 (p=< 0.001).

There was no difference in median milligrams of morphine usage on the day of operation; study = 10, placebo = 10 (p = 0.942). The morphine usage was lower in the study group on all post operative days and this was significant on days 2& 3; day 1: 10 v’s 15 (p=0.054), day 2: 10 v’s 20 (p=< 0.001), day 3: 7.5 v’s 10 (p=0.02). Median total morphine requirements over the 3 post operative days were 30mg for the study group compared to 52.5mg for the control group and this was significant (p=0.012).

The study group on average spent less nights as an inpatient with a median value of 1 compared to 2 for the control but this was not significant (p=0.430).

There were no major complications with the administration of the blocks or with the catheters.

Conclusion: The bolus of bupivacaine given to all patients prior to surgery meant that low pain scores were seen in both groups in the immediate post operative period with no significant difference between them. The continuous infusion of bupivacaine via a pain pump provided significantly better analgesia than normal saline with significantly less requirement for supplementary oral analgesic agents over the 72 hours after major ankle or hind foot surgery. This is a safe and effective method of managing post operative pain in these patients.


K Sampathkumar S Irby D Williamson

Background: Postoperative pain following hindfoot surgery can be difficult to control with opioid analgesics. Popliteal nerve blocks have been shown in the literature to be effective in both delaying the onset of postoperative pain and reducing the intensity of the pain, with a variable duration of effect. In 2007 we established a ‘block team’ of anaesthetists available to administer popliteal blocks preoperatively.

Methods: Forty-nine consecutive patients undergoing hindfoot surgery were selected. Data was collected: The proportion of patients having a block; opiate requirement during surgery, in the recovery room and on the ward; pain score; time to mobilize after surgery; and length of stay.

We compared two techniques used for popliteal block and also compared post-operative pain control with and without a popliteal block.

Results: There was a considerable increase in the percentage of patients who had a popliteal block after the block team was established (40% to 91%). Six of 23 (23%) patients needed opiates in the recovery room in the nerve block group; compared to12 of 20 (60%) patients who did not have a block. Comparing the two techniques used for the nerve block, ultrasound guidance reduced postoperative intravenous opiate usage compared to blocks given with the aid of a nerve stimulator (p< 0.05). Fifteen of 16 (94%) patients mobilized on the first post operative day in the ultrasound group compared to 16 of 23 (64%) in the patients who had no block. There were no complications recorded as a result of popliteal nerve blocks.

Conclusions: Establishing a block team has improved the proportion of patients receiving a popliteal block in hindfoot surgery in our hospital. The ultrasound guided technique gives superior results in terms of pain relief and earlier mobilization, when compared blocks administered using a nerve stimulator.


R Martin R Hartley Rajagopalan J Lloyd

Ankle fractures are common injuries affecting all age groups and constitute a large proportion of the orthopaedic trauma caseload. Frequently a large number of bed days are utilized waiting for swelling to subside and a theatre slot to become available. We audited current practice and then implemented a home therapy program (HTP). If HTP criteria were met then patients with reduced, unstable ankle fractures were taught how to use crutches and allowed home from the emergency department in order to ice and elevate at home. They were then admitted from clinic for surgery the same day and then discharged when safe and comfortable.

The purpose of this study was to prospectively compare the local management of surgically stabilised ankle fractures before and after instigating a home therapy program.

43 consecutive patients met our inclusion criteria and underwent surgical fixation of unstable ankle fractures over a three month period (February to April 2008.) The average length of hospital stay was 8 days (1–18), 4.5 days pre-operatively and 3.5 days post operatively.

Forty-eight patients underwent surgical fixation of unstable ankle fractures over a four month period (November 2008 to February 2009.) Twenty-one met the home therapy criteria. The average length of hospital stay was reduced to three days, 1.6 days pre-operatively and 1.3 days post operatively. Additionally a patient survey revealed high levels of satisfaction with the HTP.

The home therapy program has effectively reduced hospital stay both pre and post-operatively. Patients mobilising at home pre-operatively mobilise earlier post-operatively and are discharged home earlier. Over the three-month period of HTP, 131 bed days were saved which equates to a saving of £30,000.


RJ Gadd PA Storey MB Davies CM Blundell

Introduction: Several methods for the management of syndesmosis disruption during ankle fracture fixation have been documented The Tightrope anchor is a relatively new technique consisting of two buttons and a strand of Fiber-wire which is looped twice though the buttons to create a pulley effect between the fibula and tibia, thereby stabilising the ankle syndesmosis. We have reviewed the outcomes in 38 patients treated with this technique.

Materials and Methods: Data including nature of operation, complications and the need for subsequent surgery were recorded for all patients receiving a Tightrope from May 2006 to September 2008.

Results: The mean patient age was 35 years, and 23 were male. 30/38 patients required no further surgery and had a good functional outcome. Two patients had prominent fibula plates removed but achieved good functional outcomes. For one patient a Tightrope was performed following diastasis screw failure: an improved but suboptimal outcome was achieved. A patient with fibromyalgia had a good range of movement but complained of discomfort. One patient with Poland sequence, who fell post operatively, needed tightrope removal and syndesmosis debridement resulting in a good but painful range of movement. Another patient developed a pulmonary embolus following surgery and prolonged swelling and discomfort limited her functional capacity. Two patients required tightrope removal and significant wound debridement following osteomyelitis of the fibula and tibia.

Discussion and Conclusion: The Tightrope is an effective method of ankle syndesmosis repair, with a reduced need for subsequent diastasis related surgery (35/38) when compared to our diastasis screw method (100%). However, our significant rate of osteomyelitis is disturbing, warranting further investigation.


AS Shah AR Kadakia GJ Tan MS Karadsheh B Sabb

Introduction: Diagnosis of syndesmotic injuries is primarily based upon the assessment of ankle radiographs. Earlier studies examining normal radiographs are limited by small sample size and methodological issues.

Materials and Methods: One thousand four hundred and fifteen consecutive patients with ankle radiographs were reviewed. 1023 patients were excluded as a result of a history of ankle/hindfoot pain, trauma, or surgery; or radiographic evidence of ankle/hindfoot pathology. 392 patients (218 females, 174 males) with normal ankle radiographs were included. 83 of 392 patients had bilateral normal radiographs. All radiographs were reviewed independently by a fellowship-trained foot and ankle surgeon and a fellowship-trained musculoskeletal radiologist. Tibiofibular overlap and tibiofibular clear space were measured on anteroposterior (AP) and mortise radiographs. These four measurements were analyzed.

Results: Mean AP overlap was 8.3 mm (±2.5). Mean mortise overlap was 3.5 mm (±2.1), 7.7% patients had < 1 mm overlap and 4.9% of patients had < 0 mm overlap. Mean AP clear space was 4.6 mm (±1.1), 7.1% patients had > 6 mm clear space. Mean mortise clear space was 4.3 mm (±1.0), 4.3% patients had > 6 mm clear space. All measurements were significantly different between females and males (p < 0.001). Mortise clear space is the most accurate measure when obtaining contralateral radiographs. Intraobserver and interobserver reliabilities of all measurements were high (intra-class correlation coefficient range 0.820–0.983).

Discussion and Conclusion: Our data unequivocally demonstrates that basing treatment of syndesmotic injuries on previously reported radiographic criteria can lead to unnecessary operative intervention or failure to treat. Lack of overlap on the mortise view can represent a normal variant, which has not been definitively reported in prior investigations. Our data forms the basis for new radiographic criteria to evaluate syndesmotic disruption.


MD Canagasabey M Callaghan S Carley

Introduction: Foot and ankle injuries are common in the Emergency Department (ED)1. Of those which require radiographs, in accordance with the Ottawa Foot and Ankle Rules, approximately 22% have a fracture.2 In the last decade ultrasound has been developing as a tool for emergency musculoskeletal assessment – it is inexpensive, rapid and visualises soft tissue and bony structures.

Methods: This diagnostic cohort study was designed to determine whether ultrasound could detect acute bony and non-bony foot and ankle injuries. Ottawa Rules positive patients over 16 year of age without obvious dislocation/compound fracture were eligible. An ultrasound scan (USS) for bony injury was performed by a member of the ED, blinded to radiographic findings. Patient management was determined according to the radiographs. Significant fractures were defined as a breadth greater than 3 mm (as per the Ottawa Foot & Ankle Rules study group)3. All radiographic reporting was conducted blind to the results of the USS. All USS operators received a specific 2-day training in musculoskeletal ultrasound prior to the trial.

Results: One hundred and ten subjects were recruited. eleven had significant radiological fractures, ten of which were seen on ultrasound. The single missed fracture arose due to the operator not scanning proximally enough on the fibula. On re-scanning following radiographic review the fracture was clearly seen on ultrasound. To date the sensitivity of USS is 90.9%, with 95% CI (65.7, 98.3). The specificity is 90.9% with 95% CI (88.1, 91.7). The positive predictive value is 0.526, with a 95% CI (0.380, 0.569). The negative predictive value is 0.989, with a 95% CI (0.959, 0.998). The positive likelihood ratio is 10.00, with a 95% CI (5.526, 11.901) and the negative likelihood ratio is 0.100, with a 95% CI (0.018, 0.389).

Conclusion: Our pilot study demonstrates that ultrasound shows great promise for the sensitive detection of foot and ankle fractures.


S Akhtar A Fox J Barrie

The most important determinant of treatment of malleolar fractures is stability. Stable fractures have an intact deep deltoid ligament and do not displace with functional treatment. If the deep deltoid/medial malleolar complex is disrupted, the talus is at risk of displacement.

We developed clinical criteria for potential instability and applied them to a prospective series of patients. Criteria included: a medial clear space of < 4mm; medial tenderness, bruising or swelling; a fibular fracture above the syndesmosis; a bimalleolar or trimalleolar fracture; an open fracture; a high-energy fracture mechanism. Patients with a medial clear space of < 4mm and none of these criteria were considered to have stable fractures, while those with a medial clear space of > 4mm were considered to have a displaced fracture.

We studied 152 consecutive skeletally mature patients with undisplaced, potentially unstable malleolar fractures treated by the senior author between 1st January 1998 and 31st December 2007. Patients were treated in a below-knee walking cast (136 patients) or a functional ankle brace (16 patients) for six weeks. Weight bearing was encouraged throughout. Weight bearing radiographs were obtained at one week and six weeks. Displacement was defined as talar displacement with a medial clear space > 4mm. Demographic, clinical and radiological data were collected prospectively.

There were 88 male and 64 female patients, with a median age of 43 years. Criteria for possible instability were: medial tenderness, 115 patients; proximal fibular fracture, 29 patients; bimalleolar fracture, 17 patients; other criteria, 15 patients. Three fractures displaced (risk of displacement 2.0%, 95% CI 0.4–5.7%). All displaced within the first week and were treated by open reduction and internal fixation. One bimalleolar fracture developed a symptomatic medial malleolar non-union which was treated by percutaneous screw fixation (risk of non-union 5.9%, 95% CI 0.1%–28.7%). All the other fractures achieved clinical union by 8 weeks.


G Jackson S Akhtar N Roberts C McLaughlin J Barrie

Introduction: Adult acquired flatfoot is a common cause of foot pain. The majority of series describe surgery although important non-surgical series exist. This series of 166 patients gives an overview of the clinical spectrum of the condition and outcomes.

Materials and Methods: Data was collected prospectively on 166 consecutive patients with adult acquired flatfoot between 1995 and 2005. 104 patients were reviewed at a median of eight years (range 3–13). A standardised clinical examination, AOFAS hindfoot and visual analogue satisfaction scores were performed.

Results: There were 40 men (median age 56 years) and 126 women (median age 60 years). 68% had other musculoskeletal problems. Patients were Truro staged at presentation; Stage 1: 26 patients. Stage 2A: 84 patients. Stage 2B: 25 patients. Stage 2C: 23 patients. Stage 3: 6 patients. Stage 4: 2 patients.

Stage 1 patients were younger (p< 0.001). 133 patients had soft-tissue symptoms, but 33 had degenerative problems. Degenerative patients had a higher median age (p=0.0138) and stiffer deformities (p< 0.0001). Most patients (131, 78.9%) were managed conservatively. Surgery was commoner in the arthritic group (p=0.001).

Fifty-two conservatively treated feet were clinically reassessed. In 31 (59%) patients the Truro stage had not changed, 11 (21%) had improved and 10 (20%) had deteriorated. Twenty percent of patients treated with orthoses stopped using them after 18 to 24 months. In non-surgically treated patients, the median AOFAS score was 73/100 and satisfaction score 71/100. In surgically treated patients the median AOFAS score was 74/100 and satisfaction score 83/100.

Discussion: There is a young group of patients with adult acquired flatfoot, with soft tissue symptoms but no progressive deformity. There is a large group with a flexible deformity who can mostly be treated with orthoses, and an older group with stiffer, arthritic deformities who are more likely to need surgery.

Conclusion: Final outcomes and satisfaction were similar in surgically and non-surgically treated patients.


Dhukaram AK Hyde A Best

Introduction: Tibialis posterior tendon dysfunction is a common cause of foot pain and dysfunction in the middle aged patients. Initially, it presents as medial ankle pain and swelling, with or without a flexible flat foot, later progressing on to a fixed deformity. Operative management for the early stages of tendon dysfunction poses a significant workload on hospitals and physical burden on patients. We have evaluated non-operative management of early tibialis posterior tendon dysfunction (1).

Methods: This is a prospective study on patients with stage I and II tibialis posterior tendon dysfunction treated with a structured physiotherapy protocol. Twelve consecutive patients referred to a foot and ankle consultant with early tibialis posterior dysfunction from July 2008 were included in the study. The physiotherapy regime includes repetitive resisted active dorsiflexion, inversion, eversion, heel rise, and tip toe walking. The intensity of physiotherapy is progressively increased over the period of four months in four phases. Criteria for successful rehabilitation are ability to perform greater than ten single stance heel rises and tip toe walking for more than 100 yards. Patients who cannot achieve the expected progression were re-referred for surgical intervention. All the patients were referred for support with orthoses, however, only a few received the orthoses during the treatment period. The outcome was assessed using the validated outcome score Foot Function Index (FFI) before and after physiotherapy regimen.

Results: The study group consisted of 10 females and two males with 10 unilateral and two bilateral cases. The mean age was 59 years (48 to 79). The average number of physiotherapy visits was five. Prior to treatment the mean number of single stance tip toes performed by the patients was four. Out of 12 patients, ten successfully completed the rehabilitation. The mean FFI before rehabilitation was 55, which improved to 19 at the end of four months rehabilitation. On analysis using a paired t test 95% CI for mean difference: (25.07, 46.93) P < 0.0001. The improvement was consistent with all the three components of FFI (pain, activity and function) (p< 0.0001).

Conclusion: This study suggests early tibialis posterior tendon dysfunction can be treated effectively with structured physiotherapy.


IA Malek T Sumroo R Fleck M Siddique

Introduction: A Rose calcaneal osteotomy and Cobb procedure for treatment of acquired pes planus is gaining in popularity as a result of the advantages of anatomical reconstruction and reduced graft site morbidity. Although, its ability to provide long term dynamic function and effect on patient’s symptoms remains to be seen.

Materials and Methods: Twenty-two patients with stage two and three Posterior tibialis tendon dysfunction underwent surgical reconstruction with a Cobb procedure and Rose calcaneal osteotomy between 2003 and 2008. The average age was 59 years (range: 20–80 years). There were 18 females and four males.

Results: We evaluated the dynamic function of the Tibialis posterior muscle tendon function by ultra-sonograms postoperatively at mean follow-up time of 36 months. Eighty three per cent of patients achieved a single heel raise. Seventy-three percent of the patients showed an intact and mobile tibialis posterior tendon on supination and pronation movements. There was no difference in the satisfaction of patients with a tenodesis or non tenodesis.

Conclusion: Our results suggest that Cobb procedure does provide dynamic Tibialis posterior function in majority of patients.


H El-Mowafi M Refai

Background: Closed reduction of intra-articular calcaneal fractures sometimes lack the accuracy desired for restoring the normal anatomy of the articular surface of the calcaneus. In this study, we evaluate the preliminary results of closed reduction of the intra-articular calcaneal fractures with an Ilizarov frame.

Patients and Method: Forty patients (25 males and 15 females) with 50 intra-articular fracture calcaneal fractures were treated with closed reduction and an Ilizarov frame. The mean age was 25.4 years (range from 19 to 65). Union was achieved after two months. The results were evaluated on the basis of combined clinical and radiological examination at the latest follow-up. Results were classified according to the protocol and scoring system used by Paley and Hall 1993.

Results: The mean follow up period was 1.9 years (range 6 months to 4 years). At final follow up there were 15 excellent feet, 26 were good, 6 fair and 3 poor. The mean Bohler angle postoperatively was 260 (range 17 to 35). Superficial infection occurred in seven feet and was controlled. Skin pressure necrosis of the posterior aspect of the heel occurred in three feet. One needed a skin graft.

Conclusion: This method is a minimally invasive technique. The technique has the ability to restore the normal anatomy, shape and length of the calcaneal body, especially in Sander’s type III and type IV fractures. It is particularly useful for osteoprotic bone as it provides rigid fixation.


A Adler S Erqou TAS Lima AHN Robinson

Context: Diabetes is associated with a several fold increase in the risk of lower extremity amputation. Although a number of epidemiologic studies have reported positive associations between glycaemia and lower extremity amputation, the magnitude of the risk has not been adequately quantified.

Objective: To synthesize the available prospective epidemiologic data on the association between glycaemia as measured by glycosylated haemoglobin and lower extremity amputation in individuals with diabetes.

Data Sources: We searched electronic databases (MED-LINE and EMBASE) and the reference lists of relevant articles.

Study Selection: We considered prospective epidemiologic studies of cohort or nested case-control design that measured glycosylated haemoglobin level and assessed lower extremity amputation as an outcome. Of 2,398 citations identified, we included 14 studies comprising 94,640 subjects and 1,227 cases.

Data Extraction: Data were abstracted using standardized forms or obtained from investigators when published information was insufficient. Data included characteristics of case and control populations, measurement of glycaemia, assay methods, outcome, and covariates.

Results: The overall risk ratio for lower extremity amputation was 1.26 (95% CI, 1.16–1.36) for each percentage point increase in glycosylated hemoglobin level. There was significant heterogeneity across studies (I2: 76%, 67–86%; p< 0.001) not accounted for by recorded study characteristics. Among studies that reported the type of diabetic population, the combined estimate was 1.44 (1.25–1.65) for individuals with type 2 diabetes and 1.18 (95% CI, 1.02–1.38) for type 1 diabetes, but the difference was not statistically significant (p=0.09). We found no significant publication bias.

Conclusions: There a substantial increase in risk of lower extremity amputation associated with every 1% higher HbA1c in individuals with diabetes, highlighting a potential benefit of blood glucose control. In the absence of evidence from clinical trials, this paper supports glucose-lowering as a component of overall care in the patient at high risk of amputation.


AB Shah R Parmar G Ormerod J Barrie AI Zubairy AB Shah

Introduction: An osteotomy in the proximal first metatarsal corrects the metatarsal head position with much less movement of the fragment than an equivalent distal osteotomy. Most described techniques are technically demanding and reported complications including non-union, mal-union and transfer pain. We present our results of an opening wedge osteotomy with a medial wedge plate. We also present the pitfalls and tips to avoid complications.

Materials and Methods: Thirty-four procedures in 30 patients were performed using the Arthrex wedge plate. Demographic and clinical data, AOFAS scores and radiological measurements of standardised radiographs were collected for all the patients.

Results: All patients were females. The average age was 52 years. Twenty-seven were primary procedures and 7 patients had had previous, failed 1st ray surgery. No bone graft was used. Thirty-two feet showed clinical and radiological signs of union. Four complications occurred and one was treated with metatarsophalangeal joint fusion. One had an infection. Two patients had broken screws. The average hallux valgus angle and inter-metatarsal angle corrections were 200 and 90 respectively. Average increase in AOFAS scores: preoperative 47 to postoperative 81.

Discussion: The spacer in the plate acts as a pillar and obviates the need for a bony strut. Keeping an intact lateral cortex and preventing any shaft displacement was important in avoiding transfer pain. 4.5mm or smaller plates appear to have fewer problems and better scores, al though this was statistically unproven. Screw breakage in the absence of infection had no bearing on overall outcome. Some patients with poor fixation may benefit from non-weight bearing for the first 6 weeks.

Conclusion: The wedge plate osteotomy is a powerful tool to correct moderate to severe hallux valgus. It does not need additional bone graft and has a favorable clinical and radiological outcome. The prelude to optimum result was meticulous technique avoiding the discussed pit falls.


MJ Oddy MJ Flowers MB Davies

Background: A novel method for harvesting the flexor digitorum longus (FDL) tendon has previously been described via a plantar approach based on a surface coordinate. The aim of this investigation is to provide a comparison with the traditional medial midfoot dissection for tendon harvest.

Methods: The FDL tendon was exposed in 10 cadaveric feet via a limited plantar approach and also medially as far as could be accessed via the knot of Henry. The FDL was marked with a metal clip in each approach. The lengths of the skin incisions were recorded and the distance between the two markers was measured. The morphology of the FDL tendon was observed including interconnections with the flexor hallucis longus (FHL) tendon.

Results: The mean additional length of tendon accessed via the plantar approach was 22.9 mm with a mean reduction in skin incision length of 15.6 mm. The FDL tendon showed some division at the site of the plantar exposure and there were FDL - FHL interconnections in nine of the feet with three distinct patterns observed.

Conclusion: Using the plantar exposure, a longer length of tendon can be obtained through a smaller skin incision, which has been quantified here. Observations on FDL tendon morphology and interconnections may have clinical significance.


Malek P Torres T Soomro M Siddique

The surgical correction of hammertoe deformity of the lesser toes is one of the most commonly performed forefoot procedures. In general, percutaneous Kirschner wires are used to provide fixation to the resected proximal interphalangeal joint. Although these wires are effective, issues such as pin tract infection as well as difficult postoperative management by patients make alternative fixation methods desirable.

The biomechanical studies suggested that the bioabsorbable implant would be a suitable fixation device for the hammer toe procedure. These wire are made of a copolymer of 82% poly-L-lactic acid and 18% polyglycolic acid.

The aim of our study was to assess the clinical outcome of these two implants. We compared 100 consecutive proximal interphalangeal joint fusions performed with each implant. There was no statistically significant difference in the fusion rate at six months using either implant. However, there was significant statistical difference in cost, rate of infection, implant migration, recurrence of deformity, patient’s return to driving, walking with routine foot wear and satisfaction. There was 11% rate of reactive inflammation in the absorbable wire group but no infection.

The study shows the absorbable wires are safe for fusion of proximal inter phalangeal joints.


H Akrawi BJ Bolland M Healey N Savva GW Bowyer

Introduction: Functional Foot Orthoses (FFO’s) have been shown to improve one element of balance, postural sway, when prescribed for patients with ankle injuries. Little is known, however, about the effect of these devices on ankle stability/proprioception, or the changes which might occur as the patient becomes habituated to using the device. We studied these effects from the time of initial application of the FFO through to regular usage at six weeks.

Methods: Patients with musculoskeletal conditions affecting the lower limb that required custom made FFO’s were evaluated. A standardised protocol, using the Biodex stability system (a balance platform), to assess several stability indices was performed. Patients were assessed before fitting the orthosis, at the time of fitting and six weeks later. The American Orthopaedic Foot and ankle Society (AOFAS) score was also used to evaluate the progress of these patients.

Results: There were 13 male and seven female patients, aged 10 to 64 years. Patients had a range of orthopaedic conditions and all been assessed by orthopaedic specialist and podiatrist as having correctable foot biomechanics. In 6 patients, proprioception deteriorated on initial application of FFO’s. However, all patients exhibited improved over-all stability by a mean of 2.5 points (Normal range 0.82–3.35) at 6 weeks evaluation. The mean AOFAS on presentation was 72 and the final mean score was 97, both of which were clinically and statistically significant (t test, p< 0.05). Eighteen patients had complete resolution of symptoms of pain and instability.

Conclusions: FFO’s alter foot biomechanics, and in doing so appear also to improve balance and proprioception. Proprioception deteriorated in 30% of cases on initial application of orthotics, but pain and instability improved in more than 90% of patients on extended use of foot orthotics, with this improvement becoming manifest by 6 weeks after starting use of the device.


J Vernois

Introduction: Hallux valgus is a common foot deformity. A widely used method for correction of mild and moderate hallux valgus is a distal metatarsal (Chevron) osteotomy. The purpose of this study was to assess the results of a percutaneous chevron osteotomy two years after my first communication in Arcachon.

Patients and method: The operation is performed by one senior surgeon. The patient is placed in the supine position. The foot is allowed to overhang the end of the table. No tourniquet is used. The procedure is controlled by fluoroscopy. The chevron osteotomy is undertaken with a Shannon burr of 12 mm and a 20 mm for the last case. The axis of translation is determined preoperatively and adapted to the foot: more or less plantar displacement of the metatarsal head, or, more or less shortening of the metatarsal itself. The translation of the head is controlled by a temporary intramedullary K-wire inserted medially. The fixation is with an absorbable k-wire for one part and by screw for the other part. The medial exostosis is not systematically removed. The procedure is completed by an Akin osteotomy in 90%. A lateral release procedure is performed percutaneously.

Results: The mean age of the patients was 55 years at time of operation. At the follow-up of 3 months all patients are examined and X-Ray’s taken. The Kitaoka score increased from 45 to 89. The hallux valgus angle decreases from 37° to 10°. The metatarsus varus is 10°. Three patients need a new surgery for a secondary displacement. Our results are comparable to those published for open chevron osteotomy in terms of correction of the HV and intermetatarsal angles.


D Redfern Gill M Harris

Introduction: In most areas of surgery there has been a move in recent years towards less invasive operative techniques. However, minimally invasive surgery (MIS) is not automatically ‘better’ surgery. Several MIS techniques for correcting hallux valgus have been described. We present our experience with an MIS chevron type osteotomy, Akin osteotomy and distal soft tissue release. This technique utilises rigid internal screw fixation (without the need for k wire fixation). This is the first such series to be reported in the United Kingdom.

Patients & Methods: A consecutive series of twenty three patients (30 feet) with mild to moderate HV deformity were included in the study and were independently assessed clinically and radiographically and scored using the AOFAS scoring system, visual analogue score for pain and a subjective outcome score. All surgery was performed by a single surgeon (DR) using a high-speed burr to create the osteotomies. The osteotomy was fixed with a rigid screw. The mean age was 59 (24–75), and 90% were female. All patients had minimum follow-up of three months (mean 7.5, range 5–12).

Results: The mean AOFAS score improved from 39.3 (median 44, range 25–57) preoperatively to 89.9 (median 92, range 77–100) postoperatively. The mean visual analogue score improved from 7 to 1. 82% of patients were very satisfied / satisfied with the procedure. There were no cases of infection, two cases of type 1 complex regional pain syndrome and two screws required removal.

Conclusion: This small series represents the senior author’s learning curve with this new technique and as such, these early MIS results compare well with outcomes reported with modern open techniques for mild to moderate hallux valgus deformities. A randomised study to compare open and closed techniques is now being undertaken.


R Clayton M Mullen E Baird P Patterson Q Fogg S Kumar

Introduction: Tarsometatarsal joint (TMTJ) arthrodesis is traditionally performed through a dorsal approach and is associated with higher incidence of cutaneous nerve damage, prominent metalware and high non-union rates. It is postulated that applying fixation to the plantar (tension) side, rather than the dorsal (compression) side would create a more stable construct with higher union rates. A suitable surgical approach has not previously been described. The aim of this study is to define a plantar surgical approach to the TMTJ’s.

Methods: We dissected 10 cadaveric feet, identifying nerves, vessels, muscles and their innervation on the plantar aspect of the 1st and 2nd TMTJ’s.

Results: We found that in all specimens a plane of dissection could be created between the two terminal divisions of the medial plantar nerve between flexor digitorum brevis and abductor hallucis. Although exposure of the 1st TMTJ was relatively easy, access to the 2nd TMTJ was difficult due to its location at the apex of the transverse metatarsal arch and the overlying peroneus longus insertion. We found that the peroneus longus tendon had a variable insertion not only at the base of the 1st metatarsal but also at the medial cuneiform and the base of the 2nd metatarsal.

Discussion: This is a new surgical approach, following an internervous dissection plane. The feasibility of making an incision over the convex side of the rocker bottom deformity and the biomechanical advantage of a plantarly applied fixation device may make this an attractive surgical approach.


MA Fazal RL Williams

Purpose: We conducted a study of 72 hammer toes treated with proximal interphalangaeal joint (PIPJ) fusions with a Stayfuse implant. The aim of the study was to access the clinical results of PIPJ fusion carried out with Stayfuse implants.

Method: There were 10 males and 62 females. Average age was 52 years. Twelve cases had bilateral and 60 cases had unilateral foot involvement. Fifty-two second and 20 third toes were operated on. Mean follow up was twelve months. The results were assessed clinically, radiologically and with the American orthopaedic foot and ankle surgery society (AOFAS) score.

Results: All the joints fused clinically except two. There were ten PIPJ’s which did not fuse radiologically. The AOFAS score improved from 42 preoperativley to 84 post operatively. There were two cortical breeches of the proximal phalanx, one implant breakage and one case of dissociation of the components of the implant at six weeks after the surgery, with a recurrence of deformity. There were two patients who complained of over-straight toes. Fifty-two patients were very satisfied with the procedure, seventeen satisfied and three patients were unsatisfied.

Conclusion: We conclude that the Stayfuse is safe, reliable method to correct PIPJ deformity, although there is a learning curve. The main advantages of the implant are that there is no postoperative implant exposure, no violation of healthy joints, no risk of pin tract infection, rotational and angular stability, early rehabilitation and a high patient satisfaction. The disadvantages of the implant are dissociation of the components and the difficulty of removal, if this is needed.


A Kulkarni T Soomro M Siddique

Introduction: Tarsometatarsal joint (TMTJ) fusion is performed for arthritis or painful deformity. First TMTJ fusion may be performed as a part of corrective surgery for hallux valgus deformity. K-wires and trans-articular screws are often used to stabilize the joints. We present our experience with the use of locking plates (LP) for TMTJ fusion.

Patients and Methods: Thirty-three TMTJ’s in 19 patients were fused and stabilised with LP’s between January and September 2008. The procedure was performed for Lisfranc arthritis in 13 patients and Lapidus procedures in six. Two out of 6 were revisions after failed fusion using transarticular screws. Iliac crest bone autograft was used in 26 joints in 12 patients. All patients post-operatively had below knee plaster immobilization and protected weight bearing walking for first 6 weeks. Clinical and radiological surveillance continued until bone union. AOFAS midfoot scale was used as outcome measure.

Results: There were 7 male and 12 female patients with average age of 51 (14–68). The American orthopaedic foot and ankle surgery society (AOFAS) midfoot score showed a 42% improvement in pain, 30% improvement in function and 53% improvement in alignment. The average AOFAS overall score improved from 30 preoperativley to 67 postoperativley. All except one joint in one patient had clinically and radiologically fused joints. One patient underwent removal of the metalwork and four had delayed wound healing. The average satisfaction score was 7 out of 10. 86% said of patients said that they would recommend the surgery to a friend, and 91% would undergo the surgery again.

Discussion: Locking plates have been recently introduced for ankle and foot surgery. Biomechanical studies have shown that the plates are not as strong or stiff as trans-articular screw fixation, however, they are easy to use, have more flexibility for realignment and can act as a buttress for bone graft. In our series all, except one, patients achieved bony union without loss of alignment.

Conclusion: Locking plates provide satisfactory stability for TMTJ fusion, without complications.


W Cheung C Robb H Prem

We present a case control comparison between two methods of fixation for 1st metatarsophalangeal (MTPJ) fusion. From 2007–2008 sixty patients were treated with either 4.0mm ACE (De Puy) screws or a Hallu-fix (Integra LifeSciences) plate fixation. We found no difference between the two groups in regard to age, ASA grade, smoking status and non-steroidal antiinflammatory use but there was a statistically significant difference in union rates. In the Hallu-fix group, nine patients went on to develop a non-union whereas one patient developed a non-union in the ACE screw fixation group, p = 0.01. Whilst there may be perceived advantages with the Hallu-fix system in regard to the accuracy of reduction, from our results we caution against it’s use, and have found a better outcome with cheaper 4.0mm ACE screws.


J Barrie S Khan D Enion N Dodds

Introduction: Lesser metatarsophalangeal joint (MTPJ) instability is a common cause of forefoot pain. Instability is probably caused by tears of the plantar plate and collateral ligaments. We prospectively compared MRI and ultrasound with and without arthrography in the assessment of patients with MTPJ instability.

Materials and Methods: MTPJ instability was diagnosed by the draw test. Nineteen patients underwent imaging with consent. One musculoskeletal radiologist performed MRI arthrography and a different musculoskeletal radiologist performed ultrasonography supplemented with arthrography. Each radiologist reported his own study, blinded to the results of the other modality. Where possible, the radiological diagnosis was evaluated at surgery.

Results: MRI identified four full thickness plantar plate tears. In five studies no contrast was seen in the MTP joint and in 10 contrast was contained within the joint.

Ultrasound identified six full thickness plantar plate tears as hypoechoic zones that extended through the whole thickness of the plate. Eleven studies showed partial thickness tears. Two studies showed thinning of the plate. Ultrasound arthrography identified seven full thickness tears by extravasation of injected fluid into the flexor tendon sheath. Eleven studies showed partial thickness tears and one was normal. Ultrasound and ultrasound arthrography agreed in 14/19 patients. MRI agreed with ultrasound on 3 of 6 full thickness tears and with ultrasound arthrography in 4 of 6 full thickness tears. MRI gave additional information about the articular surfaces in four patients. Surgical comparison was available in 11/19 patients. Ultrasound with and without arthrography correctly predicted four partial thickness tears. Ultrasound arthrography correctly predicted 6/7 full thickness tears, MRI 3/7 and ultrasound 3/7.

Discussion: Ultrasound with arthrography appears the best modality to distinguish between partial and full-thickness tears. It is cheaper, simpler and can be performed in the outpatient setting. Larger studies with surgical confirmation are required to assess its value more precisely.


CN Peck A MacLeod J Barrie

Introduction: Lesser metatarsophalangeal instability is a common cause of forefoot pain. Previous studies were small and there is little data comparing surgical with non-surgical treatment.

Patients and Methods: Metatarsophalangeal instability was diagnosed and staged with the draw test. We recorded the clinical presentation, involved toes, severity of instability, presence of toe deformity and management. Patients were followed-up in clinic or by telephone interview with visual analogue pain and satisfaction scores and AOFAS lesser metatarsophalangeal scores. Outcomes were assessed by an independent observer.

Results: We studied 154 patients: 127 (82%) female and 27 (18%) male. The median age was 56 years (range 33–85). One foot was affected in 107 patients (69%) and both feet in 47 (31%). The second toe only was affected in 99 patients (64%) and multiple toes in 52 (34%). Seventy-three patients (47%) had a complaint of generalised forefoot pain. Sixty-eight (44%) had pain and deformity localised to the second toe. Thirteen patients (8%) had toe deformity with significant MTPJ instability. 150 toes (52%) had grade 1 instability, 108 (37%) grade 2 instability and 21 (7%) grade 3 instability. Twelve toes (4%) presented dislocated with a history of instability. Ninety-nine patients (64%) were treated conservatively, using functional taping, shoe modifications, insoles and injections. Fifty-five patients (36%) had surgery, including lesser toe straightening, flexor-extensor transfer, plantar plate repair, Weil and Stainsby procedures. 79% of patients were reviewed at a mean of 65 months (range 14 to 138). Mean pain score was 31mm ± 23.7mm for the conservative group and 23mm ± 24.1mm in the surgical group. Mean AOFAS score was 69 ± 16.3 for the conservative group and 67 ± 17.8 in the surgical group. 39 (52%) conservatively treated patients were either satisfied or very satisfied compared to 31 (66%) surgically treated patients. No differences were statistically significant.


J Luo L Daines A Charalambous MA Adams DJ Annesley-Williams P Dolan

Purpose: To determine how cement volume during vertebroplasty influences:

stress distributions on fractured and adjacent vertebral bodies,

load-sharing between the vertebral bodies and neural arch, and

cement leakage.

Methods: Nineteen thoracolumbar motion segments from 13 cadavers (42–91 yrs) were loaded to induce fracture. Fractured vertebrae received two sequential injections (VP1 and VP2) of 3.5cm3 of polymethylmethacrylate cement. Before and after each injection, motion segment stiffness was measured in compression and in bending, and the distribution of compressive “stress” in the intervertebral disc was measured in flexed and extended postures. Stress profiles yielded the intradiscal pressure (IDP), stress peaks in the posterior (SPP) annulus, and the % of the applied compressive force resisted by the neural arch (FN). Cement leakage and vertebral body volume were quantified by water-immersion, and % cement fill was estimated.

Results: Bending and compressive stiffness fell by 37% and 50% respectively following fracture, and were restored only after VP2. Depending on posture, IDP fell by 59%–85% after fracture whereas SPP increased by 107%–362%. VP1 restored IDP and SPP to prefracture values, and VP2 produced no further changes. Fracture increased FN from 11% to 39% in flexion, and from 33% to 59% in extension. FN was restored towards pre-fracture values only after VP2. Cement leakage, IDP and compressive stiffness all increased with %fill.

Conclusions: 3.5cm3 of cement largely restored normal stress distributions to fractured and adjacent vertebral bodies, but 7cm3 were required to restore load-sharing between the vertebral bodies and neural arch. Risks of cement leakage increased with %fill.

Conflicts of Interest: None

Source of Funding: This work was funded by Action Medical Research and The Hospital Saving Association Charitable Trust. Vertebroplasty materials were provided by Stryker.


SK Heathfield JA Hoyland

Background and Aims: Low back pain has been attributed to degeneration of the intervertebral disc (IVD). Increased evidence of senescence biomarkers, including the protein caveolin-1, during IVD degeneration has been demonstrated and linked with disease development rather than ageing per se, suggesting that a particular type of senescence, stress-induced premature senescence (SIPS), occurs in disc degeneration. SIPS can be induced by cytokines such as interleukin-1 (IL-1 Since IL-1 is known to be an important mediator of the catabolic events in IVD degeneration we sought to investigate whether IL-1 induces expression of the senescence biomarker caveolin-1 in IVD cells and whether its induction is associated with markers of cell senescence.

Methods: Human nucleus pulposus (NP) cells cultured in monolayer were treated for 24 hours with 10ng/ml IL-1 Quantitative real-time RT-PCR was used to assess gene expression for caveolin-1 and cell cycle inhibitors p53, p21 and p16INK4a. Cells were stained for senescence-associated-galactosidase and flow cytometry performed to analyse cell cycle position.

Results: IL-1 treatment induced transcription of caveolin-1 at 8 hours after the start of treatment. This coincided with increased expression of the cell cycle inhibitors p21 and p16INK4a expression at 2 hours and p21 and p53 at 8 hours. Flow cytometry revealed that IL-1 treatment caused a shift away from the S phase of the cell cycle and treated cells exhibited senescence-associated-galactosidase staining.

Conclusion: Our findings indicate that IL-1 induces caveolin expression and features of cellular senescence in human NP cells suggesting a role for IL-1 and caveolin-1 in SIPS within the human IVD.

Conflicts of Interest: None

Source of Funding: Furlong Research Charitable Foundation


S Owen S Roberts J Trivedi C Sharp

Background: The cells of the intervertebral disc must synthesise and maintain their surrounding matrix for it to function normally, providing all its physiological and mechanical properties. However, disc cells survive in an environment that most cells would not tolerate, ie with a low pH and relatively little oxygen. Cells which experience such potentially damaging conditions, including excessive heat, elicit a stress response and synthesise a range of proteins, called heat shock proteins (Hsps); these facilitate repair and survival or removal of damaged cells.

Methods and Results: We have studied Hsp production by disc cells, both in vitro and in vivo. We measured Hsps produced by bovine skin and disc cells grown in monolayer and heated up to 45°C and also immunostained human surgical discs for stress proteins, Hsp27 and Hsp72.

Disc cells responded differently to dermal fibroblasts; when freshly isolated they had a reduced or attenuated stress response and produced much less Hsp 70 than freshly isolated skin cells. After culturing in monolayer (by passage 2) all cells produced more Hsps. Human surgical discs produced varying amounts of Hsp, with most being produced by cells in herniated discs, particularly those within clusters of cells.

Conclusion: Our results suggest that intervertebral disc cells in vivo normally have a reduced stress response. Hsp production is considered to protect against damage, suggesting that the reduced response may contribute to disc degeneration and back pain. The prosurvival stress response of disc cells could provide a novel therapeutic target in patients with degenerative disc disease.

Conflict of Interest: None

Source of Funding: Wolfson Charitable Trust


R Field S Roberts WEB Johnson

Introduction: Increased cell senescence has been reported in the human intervertebral disc (IVD) and was associated with degenerative pathology, particularly herniation. Increased IVD innervation and blood vessel ingrowth is associated with disc degeneration and the development of back pain. This preliminary study examines whether there is a relationship between the prevalence of senescent IVD cells and the extent to which the tissue is innervated and/or vascularised.

Methods: Specimens of herniated IVD (n=16 patients: aged 36–71) were stained for senescence associated β-galactosidase activity (SA β-gal), then snap frozen and cryosectioned prior to immunolocalisation procedures to detect nerves (NF200) or blood vessels (CD34). Stained sections were counterstained with DAPI to reveal cell nuclei. The proportion of SA β-gal +ve cells was scored and the extent of neural and blood vessel ingrowth semi-quantitated.

Results: The proportion of SA β gal +ve IVD cells ranged from 6% – 91% (median=16%) and was significantly correlated with age. The degree of neural or blood vessel ingrowth ranged from tissue which contained numerous (i.e. ≥10) positive cells/cell processes to tissue which was completely aneural or avascular. However, there was no clear relationship between the presence of SA β-gal +ve IVD cells and IVD innervation or vascularisation.

Conclusions: Cell senescence has been associated with up-regulated expression of catabolic enzymes, e.g. MMPs and increased synthesis of trophic cytokines, e.g. VEGF. Such cellular activity might by thought to contribute to the pathological ingrowth of nerves or blood vessels into the IVD. The data presented here, however, does not support such a hypothesis.

Conflicts of Interest: None

Source of Funding: Institute of Orthopaedics, RJAH Orthopaedic Hospital


SL Hider D Whitehurst E Thomas NE Foster

Purpose: To evaluate whether the presence of leg pain influences healthcare use and work disability in patients with low back pain (LBP).

Methods: Prospective cohort study of primary care consulters with LBP in North Staffordshire and Cheshire. Patients completed questionnaires at baseline and 12 months, collecting data on back pain, work and healthcare utilisation. At baseline, patients were classified as reporting

LBP only,

LBP + leg pain above knee only or

LBP + leg pain extending below the knee.

Results: 456 patients had complete data and were included in this analysis. At baseline, 191 (42%) reported LBP only, 116 (25%) leg pain above the knee and 149 (33%) leg pain below the knee. In comparison to those with LBP only, patients reporting leg pain below knee were more likely to be referred to secondary care (46% vs 17%, p< 0.01), to re-consult their GP (68% vs 43%, p< 0.01) and to receive physiotherapy (40% vs 21%, p< 0.01) in the 12 months after baseline. At 12 months, those with leg pain below knee were less likely to be employed (67% vs 81%, p=0.01) than patients with LBP alone, more likely to have time off work (55% vs 31%, p< 0.01) or be on reduced work duties.

Conclusions: Self-reported leg pain is common. These patients access significantly more healthcare and are more likely to be off work over 12 months. This highlights the need for early identification of patients with concurrent leg pain and appropriate targeting of interventions to reduce work disability.

Conflicts of Interest: None

Funding source: Arthritis Research Campaign


A Coxon S Farmer C Greenough

Introduction: It has previously been reported(1,2,3) that EMG signals from the lumbar spine are highly prone to contamination by ECG artefacts. As the ECG spectrum overlaps an area of interest in the EMG spectrum this has obvious implications for the accurate analysis of EMG data.

Methods: EMG data was recorded from 192 subjects across two years (initial contact, 12 months and 24 months). When a moving average filter was applied to this raw data an obvious ECG trace could be observed in the case of a large proportion of the tests. The application of a Fast Fourier Transform on this raw data demonstrated a large low frequency spike, with little known correlation to lumbar muscle spectral characteristics, but highly indicative of an ECG signal.

As multiple source signals were recorded per test, the Independent Component Analysis technique was able to be used to split the EMG raw signal into statistically independent components. This technique is designed to take the multiple signal inputs, and convert them into multiple outputs, where the inputs are distinguishable by electrode location; the outputs are distinguishable by signal biological origin.

Results: Upon extraction, one of the signal traces showed a clear ECG trace. The Fourier Transform of this trace showed the low frequency spike, with no other signal components present. The Fourier Transform of the EMG trace showed the original EMG graph, with no low frequency peak. Specific spatial information has been exchanged for a much cleaner signal.

Conflicts of Interest: None

Source of Funding: None


P Pollintine SG Harrison A Patel DG Tilley AW Miles S Gheduzzi

Introduction: Vertebroplasty is used to treat painful osteoporotic vertebral fractures, and involves transpedicular injection of bone cement into the fractured vertebral body. During injection, the fluid cement begins to “harden” to a solid, enabling it to support mechanical load. But the mechanical efficacy of vertebroplasty can be improved by using cements which disperse evenly throughout the vertebral body during injection (1). We hypothesise that a better cement dispersion is obtained with cements that have a slower viscosity increase during hardening. We test this using a numerical model.

Methods: A computer model mimicking the plate- and rod-like morphologies of cancellous bone was loaded into a commercial fluid dynamics package (CFX). During injection, viscosity increased linearly with time to simulate the hardening behaviour of the cement (2). The rate of viscosity increase was altered to mimic the hardening behaviour of 5 different cements, with the rates of increase chosen to encompass the hardening behaviour of commercial vertebroplasty cements (1). Simulations were run for 13 seconds, with cement injection at 1.5 mm/s. Cement dispersion was quantified by the proportion of marrow replaced by cement during injection. Injection pressure was also recorded.

Results: Injection pressure increased with time (p< 0.001), and maximum pressure correlated with the rate of viscosity increase (r2=0.7). The proportion of marrow replaced at the end of the experiment was inversely proportional to the rate of viscosity increase (r2=0.85). Cements with a rapidly increasing viscosity do not fully infiltrate regions of bone with plate-like morphologies, leading to a poorer cement dispersion.

Conclusion: Cements with slower hardening characteristics are dispersed more evenly throughout cancellous bone. Such cements may provide safer and more effective vertebroplasty procedures.

Conflicts of Interest: None

Source of Funding: Bupa Foundation


S-J Whiting F Dakhil-Jerew JAN Shepperd

Introduction: Forward slip of the above vertebra may compromise the exit foramen and produce nerve root signs. Conservative management should be attempted first. However in 10–15% surgical procedures are required to control symptoms of backpain and radiculopathy.

In this cohort study, we compare the functional outcome of Dynesys in patients with degenerative spondylolisthesis categorised in three subgroups.

Material & Methods: Seventy eight patients with degenerative spondylolisthesis were treated with Dynesys. Patients were sub-grouped into Dynesys alone (group 1 n=31), Adjunct fusion (group 2 n=34) and Adjunct decompression (group 3 n=13). Three main outcome parameters were reviewed; ODI, VAS and the need for further surgeries. Patients follow up was arranged at 2 weeks, 3 months, 6 months, 12 months then annually.

Results: Average follow up was 53 months, 47 months & 55 months in groups 1, 2 & 3 respectively.

Patients with Dynesys alone had initial good improvement in ODI & VAS but this was not maintained. Secondary surgery was needed in 32% at 28.2 months.

Dynesys with adjunct PLIF showed clinically & statistically maintained ODI & VAS outcome. Secondary surgery rate was 11.7% at 26 months.

Dynesys with adjunct decompression group was favoured by clinically & statistically improved functional outcome. Second surgery was necessary in 7.6%.

Discussion: Dynesys stands as an innovative device for the treatment of backpain. However, its clinical indications were not refined. Patients with degenerative spondylolisthesis require decompression with instrumented stabilisation.

Conclusion: Dynesys alone is not recommended for degenerative spondylolisthesis.

Conflicts of Interest: None

Source of Funding: Zimmer Spine sponsored research fellowship at the Conquest hospital between 2005–2007. The funds were paid direct to the hospital for follow up and maintenance of Dynesys database. No researcher received direct fund by the company.


A Coxon R Shipley M Murray H Roper S White K Nagendar C Greenough

Background context: It is frequently stated that referred pain does not travel below the knee. However, for many years studies provoking referred pain have demonstrated pain radiating below the knee.

Methods: Over a twelve month period, 643 patients with mechanical back pain and 185 patients with nerve root compressions were seen. For each patient two body map images (front and back) were obtained. Some patients attended for review, at a minimum of six weeks after their first visit. These images were also analysed.

Composite images were created by combining all images from patients in one diagnosis group. Colour based overlays were used to analyse the body map images, to locate the locations of pain. Colour density was scaled so that the site with the most hits had a pure colour, reducing down to zero colour for sites with no hits.

Results: There were 720 nerve root compression images. 216 (30%) showed no leg pain, 91 (12.6%) showed upper leg pain, 134 (18.6%) showed lower leg pain and 279 (38.8%) showed upper and lower leg pain.

There were 1964 mechanical back pain images. 674 (34.3%) showed no leg pain, 528 (26.9%) showed upper leg pain, 308 (15.7%) showed lower leg pain and 454 (23.1%) showed upper and lower leg pain.

Conclusion: A large proportion (39%) of the mechanical back pain images indicated that the patient experienced referred pain below the knee. This has significant implications in the diagnosis of nerve root compressions, potentially leading to inappropriate surgery.

Conflicts of Interest: None

Source of Funding: None


R Froud S Eldridge M Underwood

Background and Purpose: Clinicians have expressed frustration at the difficulty of interpreting low back pain (LBP) trial outcomes. Using a suite of methods to report outcomes may aid interpretation and transition of research into practice. We aimed to facilitate consensus between LBP experts on how future trials are reported.

Methods and Results: We invited SBPR and LBP Forum members, and authors of LBP trials to participate. In the first round, participants were presented with results of a qualitative study on clinicians’ preferences for different reporting methods. They were asked to rate and comment on the appropriateness of including different reporting methods in a standardised set. In the second round, they reviewed other participants’ ratings and comments, re-rated methods, and edited a statement of recommendation for future reporting. In the final round, participants were asked if they approved of a revised statement. Consensus was measured using the RAND/UCLA appropriateness method and ratified in a meeting at LBP Forum X. Sixty-three experts participated in the study. Ninety-eight percent of participants approved a statement recommending that, where possible, results of LBP trials are reported using between-group mean differences (including advice on clinically important difference), proportion of patients improving in each group, NNT to achieve a minimally important change, and the proportion of deteriorating in each group (all with 95% CIs). Also, additional reporting methods were recommended according to needs of particular trials.

Conclusion: A high level of consensus was reached amongst LBP experts on a statement recommending a standardised set of reporting methods.

Conflict of Interest: None

Source of Funding: Barts and the London Charity


D Carnes T Mars B Mullinger R Froud M Underwood

Background: We aimed to explore the incidence and risk of adverse events associated with manual therapies.

Method: The main health electronic databases, plus those specific to allied medicine and manual therapy professions, were searched. Our inclusion criteria for relevant studies were: manual therapies only; administered by regulated therapists; a clearly described intervention; adverse events reported. We performed a meta-analysis using incident estimates of proportions and random effects models from relevant prospective cohort studies and randomised controlled trials (RCTs) published after 1997.

Results: Eight prospective cohort studies and 31 manual therapy RCTs were identified and analysed. The incidence estimate of proportions of minor or moderate transient adverse events after manual therapy was ~41% (CI 95% 17–68%) in the cohort studies and 22% (CI 95% 11.1–36.2%) in the RCTs. The estimate for major adverse events was between 0.007 and 0.13%. No deaths or vascular accidents occurred in any studies. The pooled relative risk (RR) for experiencing adverse events with exercise, or with sham, passive or control interventions compared to manual therapy was similar, but compared to drug therapies greater (RR 0.05, CI 95% 0.01–0.20) and less when compared to general practitioner or usual care (RR 1.91, CI 95% 1.39–2.64).

Conclusions: Our data indicate a very low risk of major adverse events with manual therapy, but around half manual therapy patients may experience minor to moderate adverse events after treatment. The relative risk of adverse events appears greater with drug therapy but less with usual medical care.

Conflicts of Interest: D Carnes & T Mars

Source of Funding: National Council for Osteopathic Research


R Froud M Underwood S Eldridge

Background and Purpose: How outcomes of clinical trials are reported alters the way treatment effectiveness is perceived. Clinicians interpret outcomes of trials more favourably when results are presented in relative rather than in absolute terms. However, the face validity of different methods is unclear. We aimed to explore which methods clinicians find clearest, most interpretable, and useful.

Methods and Results: We purposively sampled clinicians who see patients with low back pain (LBP) and presented them with summary reports of a hypothetical trial, reporting the results using a variety of different methods. We explored participants’ preferences for these different methods and how they would like to see future trials reported. We interviewed 14 clinicians (GPs, manual therapists, psychologists, a rheumatologist, and surgeons). Participants felt that clinical trial reports were not written with them in mind. They were familiar with mean differences, proportion improved, and number needed to treat (NNT); and unfamiliar with standardised mean difference (SMD), odds ratios and relative risk. They found the proportion improved, relative risk and NNT more intuitively understandable, and were concerned that between-group mean difference, relative risk and odds ratios may mislead. Participants thought each method uniquely contributed to their overall understanding, and that using a variety of methods to report future trials may prevent erroneous portrayal of treatment effect.

Conclusion: Clinicians who see patients with low back pain currently find it difficult to interpret LBP trials. Using a suite of methods to report outcomes may aid clinicians’ interpretation and the transition of research into practice.

Conflict of Interest: None

Sources of Funding: Barts and the London Charity


M Artus D van der Windt KP Jordan EM Hay

Objectives: To assess the evidence for a similar pattern of response to treatment among non-specific low back pain (NSLBP) patients in clinical trials.

Design: A systematic review of published trials on NSLBP and meta-analysis of within-group treatment effect calculated as the Standardised Mean Difference (SMD).

Data source: The Cochrane Register of Controlled Trials’ database (CENTRAL), April 2007.

Review methods: We included randomised controlled trials that investigated the effectiveness of primary care treatments in patients with NSLBP aged 18 years or over. We excluded trials conducted in patients with LBP of identifiable cause (e.g. disc herniation or arthritis), post-operative or post-traumatic back pain, or back pain during pregnancy or labour. We chose outcome measures commonly used in the majority of NSLBP trials, namely the Visual Analogue scale (VAS) for pain severity, Roland Morris Disability questionnaire (RMDQ) and Oswestry Disability questionnaire (ODQ) for physical functioning.

Results: 118 trials investigating a wide range of primary care treatment for NSLBP were included. In spite of heterogeneity, we found evidence for a similar pattern of symptom improvement represented by large SMDs at six weeks follow up ((0.86 for pain, 95% CI = 0.65,1.07, 0.97 for RMDQ, 95% CI = 0.66,1.28 and 0.98 for ODQ, 95% CI = 0.62,1.33) followed by much smaller further change at 13 week (pain 1.07 95% CI = 0.87,1.27, RMDQ 0.93 95% CI = 0.67,1.20, ODQ 0.92 95% CI = 0.70,1.14), 27 week (pain 1.03 95% CI = 0.82,1.25, RMDQ 0.91 95% CI = 0.59,1.24, ODQ 1.08 95% CI = 0.80,1.36 and 52 week (pain 0.88 95% CI = 0.60,1.1, RMDQ 1.01 95% CI = 0.68,1.34, ODQ 1.14 95% CI = 0.88,1.39). There was no statistically significant difference between responses in various trials arms (index treatment, active comparator treatment, placebo or sham treatment, usual care or waiting list controls). There was also no statistically significant difference between responses to pharmacological and non-pharmacological treatments.

Conclusions: NSLBP symptoms seem to improve very well and in a similar pattern in clinical trials following a wide variety of active as well as inactive treatments. It is important to explore factors other than the treatments themselves that might influence symptom improvement. Exploring possible sources of underlying heterogeneity in responses might lead to some of these factors.

Conflict of Interest: None

Source of Funding: This work is part of a PhD fellowship funded by the arc (Arthritis research campaign).


A Henley AH McGregor

Patients have an important role in evaluating the health-care they receive; including the treatment they receive as well as the healthcare process. This information can be invaluable in understanding patient needs and developing a more patient centred approach to health care. As part of an RCT into the post-operative management of spinal surgery we explored patient’s experience of the health care system and their perceptions of how the system worked for them.

To date 201 patients have completed the trial; 60 receiving usual care, 37 an educational booklet, 48 rehabilitation and 56 received both booklet and rehabilitation after decompression surgery for stenosis or disc prolapse. The majority (82%) were referred to the consultant through their GP. 40% identified a specific event that led to their pain; of these 48% reported a longstanding pain and 33% noting a sudden injury. 30% waited less than a month for surgery, and 32% 1–3 months. 18% experienced surgical cancellations. The majority of patients felt well informed pre-operatively, had faith in their surgical team and had sufficient time to discuss their condition. Similarly during their operative stay they felt supported and in good hands. When questioned about their feelings on the health care process as a whole; positive patient comments included: the speed and quality of surgery and the pain relief experienced; whilst negative comments included: lack of information or advice, the delays between diagnosis and management, dissatisfaction with GP care, feeling abandoned, lack of respect from the surgeon, and disappointment with the outcome.

Conflict of Interest: None

Source of Funding: ARC


I Ali C Ulbricht AH McGregor

Increasing attention has focused on the spinal muscles with respect to stability and low back pain (LBP) with suggestions of a de-conditioning syndrome. What is less clear is the extent of this degeneration and whether it is a long term of short term consequence of LBP. This study sought to explore the cross section area (CSA) and muscle quality of the spinal extensor group in a subset of LBP patients.

MRI scans of 100 spinal clinic patients were retrospectively reviewed; sagittal and transverse (from levels L3-5) images were annoymised and archived along with details of age, gender and presenting symptoms. An image analysis package was used to determine CSA of the extensor muscle groups, and levels of fat infiltration were calculated using a pseudocolouring technique.

46 patients had spinal stenosis (28 males, 18 females, mean age 66±14.2 years) and 54 had a disc prolapse (28 males, 26 females, mean age 50±12.9 years). CSA was significantly smaller in the stenotics at both L3/4 and L4/5. Patients presenting with leg pain and a disc herniation had a significantly smaller CSA (p< 0.01) at L3/4 and L4/5 levels. A left right CSA asymmetry was noted but this was not specific to diagnosis, or presenting symptoms. Fat infiltration was present in both groups but was significantly greater in the stenotic group (p< 0.01) and was present at a similar degree at all spinal levels. Multiple regression analysis confirmed that reduced CSA was linked to leg pain (p< 0.01) and age was linked with fat infiltration (0< 0.01).

Conflict of Interest: None

Source of Funding: None


NJ Artz K Daniels L Joslin W MacFaul E Rintoul P Dolan

Background: Neck pain is a growing problem which is linked to occupational factors that include work above shoulder height or sustained neck flexion. These activities may induce fatigue in the neck muscles impairing the muscles’ ability to provide reflex contractions that protect against tissue injury. The aim of this study was to investigate the effect of neck muscle fatigue on reflex activation of the neck muscles.

Methods: Healthy volunteers were subjected to one of two loading protocols. Isometric contractions of neck extensors at 60% MVC were sustained to the endurance limit (n=30) to induce high level fatigue in these muscles. A similar protocol for neck flexors (n=21) was used to initiate low level contraction of the extensors which are co-activated to stabilise the cervical spine under such circumstances. Before and after each loading protocol, reflex activation of the trapezius muscle was assessed using skin surface electromyography (EMG) to measure the latency and amplitude of muscle activation in response to a sudden perturbation of the head.

Results: Reflex latencies increased from 73±17ms to 93±27ms (p=0.0041), and from 72±12ms to 97±28ms (p< 0.0001) following low and high level extensor fatigue, respectively. Time to peak EMG also increased from 122±32ms to 148±39ms (p=0.0093), and from 113±15ms to 138±25ms (p< 0.0001), respectively, although no change in peak EMG amplitude was observed.

Conclusions: Reflex activation of trapezius was substantially delayed following both loading protocols. These findings suggest that even low level postural loading in the workplace may impair neck muscle reflexes rendering the underlying tissues more vulnerable to strain injury.

Conflicts of Interest: None

Source of Funding: BBSRC (Biotechnology and Biological Sciences Research Council, UK)


NJ Artz MA Adams P Dolan

Background: Sensorimotor mechanisms that control activation of neck and trunk muscles are important in preventing injury to spinal tissues. People with back pain often show delayed reflex activation of trunk muscles, and such impairment increases the risk of future back pain. The aim of this study was to investigate whether sensorimotor impairment is evident in patients with neck pain.

Methods: Measures of sensorimotor function were assessed in fourteen patients with chronic, non-traumatic neck pain and forty healthy controls. Position sense was evaluated using the Fastrak electromagnetic tracking device to assess angular errors during head repositioning tasks. Movement sense was assessed using a KinCom dynamometer to determine the time taken to detect head motion at 1°s-1 and 10°s-1. Reflex responses were assessed using surface electromyography to determine the onset of muscle activation (reflex latency) in trapezius and sternocleidomastoid muscles, following perturbations of the head.

Results: Neck pain patients showed increased angular errors in reproducing upright postures, compared to controls (2.24±1.21° vs 1.85±1.06° respectively; p=0.01), and faster movement detection times (385±98ms vs 540±182ms respectively; p=0.0052). Reflex activation of trapezius was delayed in patients, indicated by a 20ms increase in reflex latency (89±19ms vs 69±21ms in controls; p=0.0039).

Conclusions: Sensorimotor function is altered in patients with neck pain. Enhanced movement detection suggests some afferents become hypersensitive in response to pain. However, impaired position sense and reflex activation suggest that some proprioceptors, including muscle spindles, develop a reduced sensitivity to mechanical stimuli. These changes may impair reflexive muscle protection and expose the cervical spine to repetitive minor injuries.

Conflicts of Interest: None

Source of Funding: BBSRC (Biotechnology and Biological Sciences Research Council, U.K.)


M Stefanakis J Luo P Pollintine MA Adams

Background: Neck muscles stabilise the head, but muscle tension imposes high compressive forces on the cervical spine. Little is known about which structures resist these high forces.

Purpose: To quantify compressive load-sharing within the cervical spine.

Methods: Seventeen cervical “motion segments” from cadavers aged 54–92 yr (mean 72 yr), were subjected to 200 N compression while positioned in simulated flexed and extended postures. Up to 5 Nm of bending was applied in various planes. Vertebral movements were recorded at 50 Hz using an optical MacReflex system. Tangent stiffness was calculated in compression and in bending. Load-sharing was evaluated from compressive stress measurements obtained by pulling a pressure transducer through the intervertebral disc. All measurements were repeated after 2 hr of creep loading at 150 N, and following sequential removal of the spinous process, apophyseal joints and uncovertebral joints.

Results: Most compression was resisted by the disc. However, creep increased compressive load-bearing by the neural arch, from 21% to 28% in flexed posture, and from 27% to 45% in extended posture, with most of this loading being resisted by the apophyseal joints. Uncovertebral joints resisted 10% of compression in extended posture, and 20% in flexed posture. Flexion and extension movements were resisted primarily by ligaments of the neural arch, and by the apophyseal joints, respectively, whereas lateral bending was resisted mostly by the apophyseal and uncovertebral joints.

Conclusion: Cervical apophyseal joints play a major role in compressive load-bearing, and also offer strong resistance to backwards and lateral bending. Uncovertebral joints primarily resist lateral bending.

Conflicts of Interest: None

Source of Funding: Scholarship from the Greek Government


J Luo P Pollintine P Dolan MA Adams

Background: Continuous bone “creep” under constant load can cause measurable deformity in cadaveric vertebrae, but the phenomenon is extremely variable.

Purpose: We test the hypothesis that vertebral micro-damage accelerates creep deformity.

Methods: Twenty-six thoracolumbar “motion segments” were tested from cadavers aged 42–92 yrs. Bone mineral density (BMD) of each vertebral body was measured using DXA. A 1.0 kN compressive force was applied for 30 mins, while the height of each vertebral body was measured using a MacReflex optical tracking system. After 30 mins recovery, one vertebral body from each specimen was subjected to controlled micro-damage (< 5mm height loss) by compressive overload, and the creep test was repeated. Load-sharing between the vertebral body and neural arch was evaluated from stress measurements made by pulling a pressure transducer through the intervertebral disc.

Results: Creep was inversely proportional to BMD (P=0.041) and did not recover substantially after unloading. Creep was greater in the anterior vertebral body cortex compared to the posterior (p=0.002). Vertebral micro-damage usually affected a single endplate, causing creep of that vertebra to increase in proportion to the severity of damage. Anterior wedging of the vertebral bodies during creep increased by 0.10o (STD 0.20o) for intact vertebrae, and by 0.68o (STD 1.34o) for damaged vertebrae.

Conclusion: Creep is substantial in elderly vertebrae with low BMD, and is accelerated by micro-damage. Preferential loss of trabeculae from the anterior vertebral body could explain why creep is greater there, and so causes wedging deformity, even in the absence of fracture.

Conflicts of Interest: none

Source of Funding: Action Medical Research


P Pollintine MSLM van Tunen J Luo M Brown P Dolan MA Adams

Background: Intervertebral discs and vertebrae deform under load, narrowing the intervertebral foramen and increasing the risk of nerve entrapment. Little is known about these deformations in elderly spines.

Purpose: To test the hypothesis that, in ageing spines, vertebrae deform more than discs, and contribute to time-dependent creep.

Methods: 117 thoracolumbar motion segments, mean age 69 yr, were compressed at 1 kN for 0.5, 1 or 2 hr. Immediate “elastic” deformations were followed by “creep”. A three-parameter model was fitted to experimental data to characterise their viscous modulus E1, elastic modulus E2 (initial stiffness), and viscosity η (resistance to fluid flow). Intradiscal pressure (IDP) was measured using a miniature needle-mounted transducer. In 17 specimens loaded for 0.5 hr, an optical MacReflex system measured compressive deformations separately in the disc and each vertebral body.

Results: On average, the disc contributed 28% of the spine’s elastic deformation, and 51% of the creep. Elastic, creep, and total deformations of 84 motion segments over 2 hrs averaged 0.87mm, 1.37mm and 2.24mm respectively. Measured deformations were predicted accurately by the model, but E1, E2 and η depended on loading duration. E1 and η decreased with advancing age and degeneration, in proportion to falling IDP (p< 0.001). Total compressive deformation increased with age, but rarely exceeded 3mm.

Conclusions: In ageing spines, vertebral bodies show greater elastic deformations than intervertebral discs, and a similar amount of creep. Deformations depend largely on IDP, but appear to be limited by impaction of adjacent neural arches. Total deformations are sufficient to cause foraminal stenosis in some individuals.

Conflicts of Interest: none

Source of Funding: Action Medical Research


WEB Johnson R Field S Roberts

Introduction: Intervertebral disc (IVD) cell transplantation is used to treat back pain. However, IVD cell activity may also contribute to pathology, e.g. IVD cells can undergo senescence or promote nerve growth, which in the IVD is associated with discogenic back pain. Serum deprivation of bovine IVD cells results in cell senescence. We have examined the influence of oxygen supply combined with serum deprivation on human IVD cells.

Methods: Cells from herniated IVD (n=3 patients) were subjected to serum deprivation and then cultured under hypoxic (1%) or atmospheric (21%) conditions for 10 days. IVD cell growth, viability and cell senescence (via Senescence Associated β-galactosidase activity; SA β-gal) were examined. The growth and migration of HMEC-1 (endothelial) and SH-SY5Y (neuronal) cells treated with conditioned medium from the IVD cell cultures (1% versus 21% oxygen) were subsequently monitored.

Results: Hypoxia significantly decreased IVD cell proliferation, but was also found to reduce cell senescence. Hence, the proportions of SA β-gal positive IVD cells in 1% and 21% oxygen at day 10 were 18±6% and 56±10%, respectively. There was no marked difference in cell viability (> 95%). Conditioned medium from IVD cells cultured under hypoxia stimulated endothelial and neural cell growth (determined via the MTS assay) and endothelial cell migration and neurite outgrowth to an extent that was significantly greater than conditioned medium from IVD cells cultured at 21% oxygen.

Conclusions: The trophic activity of human IVD cells is responsive to oxygen supply. However, hypoxia may influence the capacity of IVD cells to reduce back pain for better or worse.

Conflicts of Interest: None

Source of Funding: Institute of Orthopaedics, RJAH Orthopaedic Hospital.


K Greenfield D Sandeman

Diagnostic imaging in LBP is controversial. Concerns relate to costs and “creating potential barriers to recovery”.

Methods: All GPs in north Bristol (population 250,000) submitted every non-emergency referral for LBP+/−sciatica to our office, as a “single point of entry” clinic. 1301 patients have been assessed, 1283 with MRI screening.

We calculated proportions of MRI diagnoses and treatment pathways, and compared these with routine care (the pre-existing service, having comparable protocols, other than MRI screening.

Results: Summary of MRI diagnoses - potential surgical spine pathology 519(40.5%) (disc prolapse=295, stenosis=148, spondylolisthesis=49, other=27); serious pathology (tumours, aortic aneurysms) 12(0.94%); spondylosis 681(53%); no degenerative change- 71(5.5%).

Only 149(11.6%) of patients needed follow-up in clinic (30–58% in routine care). Overall, 637(49.6%) patients were managed in primary care, and 646(50.4%) were referred to secondary care, including 161(12.5%) referred for surgery, comparable to routine care (12–16% surgery), and 406(31.6%) patients referred to consultant pain physicians.

Discussion: In the new service, time from referral to diagnosis/treatment planning reduced from 12–16 weeks to three weeks. MRI screening did not increase referrals for surgery. Costs were minimised by leasing downtime on NHS scanners, with dedicated lumbar spine sessions leading to increased scans per hour. Very low follow-up rate further reduced costs.

The use of MRI as a tool to advise LBP patients on the spectrum of management options is arguably the way of the future. We would however, not recommend this without subsequent clinical review by an experienced clinician, including a discussion about the relevance of the findings.

Conflicts of Interest: None

Source of Funding: None


CEW Aylott R Puna C Walker PA Robertson

Background: The Lumbar Spinous Processes (LSP) have an important anatomical and biomechanical function. They also influence access to the spinal canal for neural decompressive surgical procedures. There is evidence that various anatomical structures have altered morphology with ageing, and there is anecdotal evidence of changing LSP morphology with age. This study aims to clarify the influence of age on LSP morphology, and on lumbar spine alignment.

Method: 200 CT scans of the abdomen were reformatted with bone windows allowing precise measurement of LSP dimensions, and Lumbar Lordosis. Observers were blinded to patient demographics. Inter-observer reliability was confirmed.

Results: The smallest LSP is at L5. The male LSP is on average 2–3mm higher and 1mm wider than the female LSP. LSP height increases significantly with age at every level in the lumbar spine (P< 10-5 at L2). The LSPs increase in height by 2–5mm between 20–85 years of age (P< 10-6), which was as much as 31% at L5 (P< 10-8). Width increases proportionally more, by 3–4mm or greater than 50% at each lumbar level (P< 10-11). Lumbar lordosis decreases in relation to increasing LSP height (P< 10-4) but is independent of increasing LSP width (P=0.2).

Conclusions: The height and width of the spinous processes increases with age. Increases in spinous process height are related to a loss of lumbar lordosis and may contribute to sagittal plane imbalance.

Conflicts of Interest: None

Source of Funding: None


M Stefanakis MA Adams M Sharif R Gordon GC Desmond A Ritchie A Kay I Harding

Background: Severe and chronic back pain often originates from degenerated intervertebral discs, probably from lesions in the outer posterior anulus. Unlike the nucleus, the outer anulus has a high cell density and adequate metabolite transport. The outer annulus can heal after injury in small and young experimental animals, but little is known about the healing potential of adult human discs.

Purpose: We seek evidence that healing of the human outer anulus follows the three stages of tendon healing: inflammation, repair, remodelling. If so, then manual therapy and self-treatment techniques known to facilitate tendon healing could be adapted to treat discogenic back pain.

Methods: Anulus tissue was removed at surgery (usually posteriorly) from 14 patients with discogenic back pain. Tissue was paraffin embedded and sectioned at 5 μm for histology and immunohistochemistry. Apoptosis was detected using an antibody for caspase-3.

Results: Fissures in the peripheral posterior annulus, and herniated tissue fragments, were associated with blood vessels, inflammatory cells, and with focal loss of proteoglycans. Cell density decreased with distance from fissures from the disc periphery. Overall cell density decreased with age. Apoptosis was greater in the nucleus than in the annulus, and was particularly associated with cell clusters, and with anulus fissures.

Conclusion: These preliminary results suggest an inflammatory healing response in the outer anulus, strongly associated with radial fissures. Loss of proteoglycan from fissure margins may facilitate the ingrowth of capillaries and nerves, which then stimulate local healing in the vicinity of the fissures.

Conflicts of Interest: None

Source of Funding: BackCare


SK Tolofari SM Richardson JA Hoyland

Introduction: Intervertebral disc (IVD) degeneration is a major underlying factor in the pathogenesis of chronic low back pain. The healthy IVD is both avascular and aneural, however during symptomatic degeneration there is ingrowth of nociceptive nerve fibres and blood vessels into proximal regions of the IVD. Semaphorin 3A (sema3A) is an axonal guidance molecule with the ability to repel nerves. This study aimed to identify whether class 3 semaphorins were expressed by cells of the IVD and addresses the hypothesis that they may play a role in repelling axons surrounding the healthy disc thus maintaining its aneural condition.

Methods: Forty human IVD samples were investigated using RT-PCR and immunohistochemistry to identify the expression of sema3A, 3F and their receptors; neuropilins (1 & 2) and plexins (A1-4). Serial sections were stained for PGP9.5 and CD31 to correlate semaphorin expression with nerve and blood vessel ingrowth respectively.

Results: Sema3A protein, localised primarily to the OAF, was expressed highly in the healthy disc. In degenerate samples sema3A expression decreased significantly in this region, although chondrocyte clusters within the degenerate NP exhibited strong immunopositivity. mRNA for sema3A receptors was also identified in healthy and degenerate tissues. CD31 and PGP9.5 were expressed most highly in degenerate tissues correlating with low expression of sema3A.

Conclusions: This study is the first to establish the expression of semaphorins and their receptors in the human IVD with a decrease seen in the degenerate symptomatic IVD. Sema3A may therefore, amongst other roles, act as a ‘barrier’ to neuronal ingrowth into the healthy disc.

Conflicts of Interest: None declared

Sources of Funding: Arthritis Research Campaign


PA Hendrick LA Hale ML Bell S Milosavljevic DA Hurley-Osing SM McDonough DG Baxter

Background: Activity advice and prescription are commonly used in the management of low back pain (LBP). However, no research has assessed whether objective measurements of physical activity predict outcome, recovery and course of LBP.

Methods: One hundred and one patients with acute LBP were recruited into a longitudinal cohort study. Each participant completed the Roland Morris Disability Questionnaire (RMDQ), Visual Analogue Scale and a “simple” activity question, detailing whether they had resumed full “normal” activities (Y/N), at baseline (T0) and 3 months (T1); Baecke Physical Activity Questionnaire, Fear-Avoidance Beliefs Questionnaire and the 12-item General Health Questionnaire at T0. Physical activity was measured for 7 days at T0 and T1 with an RT3 accelerometer and the seven day physical activity recall questionnaire (7d-PAR).

Results: The only significant predictor of RMDQ change was RMDQ score at T0 (p < .0001). Physical activity change did not predict RMDQ change in both univariate (p = 0.82) and multivariate analysis (p = 0.84). Paired t-tests found a significant change in RMDQ (p < .0001) and return to full “normal” activities (p < .0001) from T0 to T1, but no significant change in activity levels measured with the RT3 (p = 0.56) or the 7d-PAR (p = 0.43). RMDQ change (OR 1.72, p = 0.01) and RMDQ at T1 (OR 0.65, p = 0.04) predicted return to full “normal” activities at T1.

Conclusions: These results question the role of physical activity in LBP recovery and the assumption that activity levels change as LBP symptoms resolve.

Conflicts of Interest: None

Sources of Funding: This research was supported by a University of Otago Establishment Grant


ML van Hooff J O’Dowd C Pither M de Kleuver PW Pavlov J van Limbeek

Purpose: The long term effects of treatment in a cohort of patients with chronic low back pain (CLBP) participating in an intensive pain management program.

Background: Cognitive behavioral treatments produce clinically relevant benefits for patients with CLBP.

Methods: The program provided by RealHealth-Netherlands is based on cognitive behavioral principles and executed in collaboration with orthopedic surgeons. Primary outcomes were daily functioning and self-efficacy. Measurements were at baseline, last day of residential program and at 1 and 12 months follow-up. A GLM procedure with repeated measures was applied to examine changes over time and to explore possible unwanted side effects. Effect sizes are analyzed using cohen’s d. Clinical relevance was examined using minimal clinical important differences (MCID) estimates for primary outcomes and quality of life. To compare results with literature Standardized Morbidity Ratios (SMR) were determined.

Results: 107 patients with CLBP participated. Mean scores on primary and secondary outcomes showed a similar pattern: improvement immediately after following the program and maintenance of results over time. Effect sizes were 0.9 for functioning and 0.8 for self-efficacy. Clinical relevancy: 79% reached MCID on functioning, 53% on self-efficacy and 80% on quality of life. Found study results were 36% better and 2% worse when related to previous research on respectively rehabilitation programs and spinal surgery for similar conditions (SMR 136% and 98%respectively).

Conclusion: The participants of this evidence based program learned to manage CLBP, improved in daily functioning and quality of life. The study results are comparable with results of spinal surgery and even better than results from less intensive rehabilitation programs.

Conflict of Interest: None

Sources of Funding: None


Yoann Buisson Maria Catley Jessica Guzman Lopez Alison H McGregor Paul H Strutton

Introduction: Changes in the central nervous system (CNS) pathways controlling trunk and leg muscles in patients with low back pain and sciatica have been demonstrated. The aim of this study is to investigate whether these changes are altered by surgery.

Methods: Corticospinal excitability was examined on 2 occasions in 15 patients prior to and 6 weeks following lumbar decompression surgery and 7 control subjects – at the same time intervals. This was achieved by recording electromyographic (EMG) activity from tibialis anterior (TA), soleus (SOL), rectus abdominis (RA), external oblique (EO) and erector spinae (ES) muscles at the T12 & L4 levels in response to transcranial magnetic stimulation (TMS) of the motor cortex.

Results: A significant asymmetry in the cortical silent period (cSP) between the side ipsilateral to the pain and the contralateral side was found pre- but not post surgery in ES at L4 (P=0.012) and SOL (P=0.039). An asymmetry in the size of motor evoked potentials (MEPs) was also found in TA (P=0.009) which was no longer significant post surgery. Abdominal responses could be recorded in 10 subjects, where significant decreases in contralateral cSP in EO (P=0.021) and RA (P=0.033) were found. In controls no significant differences or changes were found.

Discussion: These results show significant asymmetries in the CNS control of trunk and leg muscles in patients prior to surgery to relieve pain which are resolved by the surgery. The degree of change in asymmetry may reflect the variability in surgical outcome. This work is currently ongoing.

Conflicts of Interest: None

Funded by: the DISCS foundation


SM McDonough RF Hunter M Tully DM Walsh S Dhamija SM McCann SD Liddle P Glasgow C Paterson G Gormley D Hurley A Delitto J Park I Bradbury GD Baxter

Background and Purpose: Current clinical guidelines recommend supervised exercise as a first-line treatment in the management of low back pain (LBP). To date studies have not used objective forms of measuring changes in free-living physical activity (FLPA). The aim of this study was to compare FLPA between two groups who received either supervised exercise and auricular acupuncture (EAA) or exercise alone (E).

Methods: 51 patients with non-specific LBP [mean±SD=42.8±12.4 years] wore an accelerometer for 7 days at baseline, end of the intervention (week 8) and follow up (week 25). FLPA variables were extracted: % time (hours) spent in postures; daily step count and cadence. Data were analysed using SPSS (v15). Repeated measures ANCOVA were performed using a mixed linear model.

Results: There was no difference in daily step count between the two groups at any time point (E, mean±SD, week 1, 8197±2187; week 8, 8563±2438, week 25, 8149±2800; EAA, mean±SD, week 1, 8103±1942; week 8, 8010±2845, week 25, 8139±1480, p=0.9) or cadence. No differences in postures were noted, apart from time sitting/lying which was shorter at week 25 in the E group (p=0.006).

Conclusions & Implications: Supervised exercise classes, with or without acupuncture, do not produce changes in FLPA in the short term or longer term in people with LBP. This suggests more effective ways should be sought to encourage the patient to incorporate activity into their daily lives. These findings have informed the design of two walking intervention trials for LBP patients.

Conflict of Interest: None

Sources of Funding: Research and Development Office, Northern Ireland, Strategic Priority Fund, Department of Employment and Learning, Northern Ireland.


NAS Kendall AK Burton CJ Main PJ Watson

Background: Psychosocial factors are well-known contributors to the suffering and disability associated with common musculoskeletal problems. How to identify salient obstacles to recovery or return to work, and how to manage them effectively remains difficult. This project interpreted the evidence base and presented it as solution-focused guidance for everyday practical use by the key players (clinicians, employers, funders, case managers, etc) to help people remain active and working.

Methods and Results: Two methods were used to identify evidence and practical advice, and synthesize this into use-able statements:

existing reviews;

an international think tank charged with producing updated reviews and identifying research gaps.

An extended conceptual development of a ‘flags framework’, based on the earlier approach of Yellow Flags, was used to prepare an easily understood and pragmatic approach. The framework integrates obstacles related to the person (yellow flags), the workplace (blue flags) and the context (black flags). A full-colour 32-page document suitable for distribution as both print and electronic media was developed. This contains a clear explanation of how to identify psychosocial flags, how to develop a plan to address them effectively, and how to take action to overcome the obstacles. Poster-style summaries for clinicians, the workplace, and the individual are included, and are available for download. International consultation was used to ensure system-independent applicability and language.

Conclusion: The new document provides practical guidance on identifying and managing psychosocial issues relevant to common musculoskeletal problems based on the latest evidence and conceptual approaches.

Conflict of Interest: none

Sources of Funding: Society for Back Pain Research, Faculty of Occupational Medicine, BackCare, Transport for London, Royal Mail, HCML, TSO


U Jones V Sparkes M Busse S Enright R van Deursen

Background: Postural re-training is one element used in the physiotherapeutic management of spinal disorders. Clinicians need outcome measures that are accurate, reliable and easy to use to monitor effects of treatment and to provide justification for the management of these conditions. This study aimed to assess the reliability of digital video analysis of thoracic, neck and head tilt angles using one measurer within one day.

Methods: Twenty healthy subjects were recruited. L4, C7 spinous processes and tragus were marked on the skin and identified with reflective markers. The subject sat in a relaxed comfortable position in a chair and was video recorded from a lateral view for one minute. The markers were removed and the subject rested, in a chair, for a few minutes. Two further recordings were taken in the same day. Still images were taken at 30seconds of the recording and were analysed using a bespoke programme within MATLAB software. Analysis included Intraclass Correlation Coefficients (ICCs) and Bland Altman plots.

Results: Excellent reliability was ascertained for thoracic, neck and head tilt angles identified by ICC of 0.94 (mean difference 0.34° ±4.7°), 0.91 (mean difference 1.1°±3.7°) 0.84 (mean difference 0.9°±4.9) respectively. All points, except one for neck angle and head tilt angle and two for thoracic angles, were within 95% limits of agreement.

Conclusion: Digital video analysis using MATLAB is a reliable way to measure thoracic, neck and head tilt angles. This is an inexpensive method for measuring posture that could be used in the management of people with spinal disorders.

Conflict of Interest: None

Source of Funding: This study has been financially supported by the Physiotherapy Research Foundation, UK and Research Collaboration Building Capacity Wales (rcbc Wales).


P Pollintine GW Barrett R Norman H Morrow F Croft E Carlisle LR Green SA Lanham C Cooper ROC Oreffo P Dolan

Background: Intrauterine protein restriction in rodent models is associated with low bone mass which persists into adulthood. This study examined how early nutritional compromise affects the mechanical and structural properties of spinal tissues in sheep throughout the lifecourse.

Methods: Lumbar spines were removed from 19 sheep; 5 control animals and 14 that received a restricted diet in-utero. Eight animals (2 control/6 diet) were sacrificed at a mean age of 2.7 years and eleven at a mean age of 4.4 yrs. Two motion segments from each spine were tested on a hydraulically-controlled materials testing machine to determine their mechanical properties. Vertebral bodies were assessed for a number of structural parameters including cortical thickness and area, and regional trabecular density.

Results: Younger animals in the diet group showed a 25% reduction in forward bending stiffness (p< 0.05) and a 32% reduction in extension strength (p< 0.05) compared to controls of the same age. Furthermore, these young animals showed a 25% reduction in the thickness of the anterior cortex (p< 0.001) and an 18% reduction in the thickness of the superior cortex (p< 0.02). In older animals, no differences were observed in any of the mechanical parameters examined between diet and control groups, although animals in the diet group showed an average increase in cortical thickness of 14%, across all regions (p< 0.01).

Conclusions: These results suggest that early nutritional challenge can have detrimental effects on the mechanical and structural properties of spinal tissues in young animals but that adaptation occurs over the lifecourse to compensate for these differences in older animals.

Conflicts of Interest: None

Source of Funding: None


C Coole PJ Watson A Drummond

Background: Low back pain (LBP) can affect work ability. Retention of employment relies on appropriate management by employer and employee, and the healthcare that the employee may access. Healthcare in the UK has historically not been work-focused. The UK government has directed the NHS to play a greater role in enabling people with health conditions to remain in work.

Purpose: The aim of this study was to explore patients’ experiences of healthcare interventions regarding the management of work problems due to LBP.

Method: Individual semi-structured interviews were conducted with twenty-five LBP patients who had been referred for multidisciplinary back pain rehabilitation. All were in employment and concerned about their ability to work with LBP.

Findings: Although the participants had received a range of healthcare interventions, these had failed to alleviate their concerns about working with LBP. There was little evidence of work-related advice or interventions provided by any of the clinicians treating the participants. In a number of cases, patients had remained at work despite the recommendations they had received. Clinicians depended on the patient as an information channel rather than creating opportunities for ‘stakeholder’ dialogue and joint problem-solving.

Conclusions: Healthcare professionals need to improve their ability to explain the nature of persistent and recurrent LBP and to explore their patients’ concerns about working with pain. They should take more active steps to address those concerns, e.g. by communicating directly with employers where necessary, by advising patients how to address actual or perceived negative attitudes at work, and how to access modifications if required.

Conflicts of Interest: None

Source of Funding: Arthritis Research Campaign


K Balasubramanian W Mahattanakkul K Nagendar CG Greenough

Design of study: Prospective, observational

Purpose of the study: Obese and morbidly obese patients undergoing lumbar surgery can be a challenge to the operating surgeon. Reports on the perioperative data in this group of patients are scarce. The purpose of the study is to prospectively compare the perioperative data in patients with normal and high BMI, undergoing lumbar spine surgery.

Method: We conducted a prospective audit of 50 consecutive patients who underwent primary discectomy or single level decompression under the care of single spine surgeon. Initial Low Back Outcome Score, length of incision, distance from skin to spinous process, distance from skin to lamina, length of hospital stay, blood loss and complications were studied in detail.

Results: We used student t test to compare the two groups and Pearson Correlation to correlate the data against high BMI. We were unable to demonstrate a statistically significant difference between those with normal BMI and high BMI in any of the above parameters analysed.

Conclusion: A high BMI was not associated with an increased perioperative morbidity in this patient group. Contrary to other areas of orthopaedic surgery, there is no statistically significant difference in the Initial Low Back Outcome Score and perioperative data between patients with normal and high BMI undergoing lumbar discectomy and single level decompression.

Conflict of Interest: None

Source of Funding: None


FE Rowan N O’Malley A Poynton

Introduction: Recombinant human bone morphogenic protein-2 (rhBMP-2) eliminates the need for iliac crest bone graft and has superior fusion rates in anterior interbody fusion1. Post-operative neck swelling has precluded its use in cervical fusion2. Peri-rhBMP-2 oedema is a proposed cause of neuropathic leg pain in posterolateral lumbar fusion. We aimed to compare the incidence of leg pain in a rhBMP-2 treated cohort with a control group following posterolateral lumbar fusion and to determine radiological evidence of a mechanical cause for leg pain in either group.

Methods and Results: A single surgeon, multi-centre elective practice was retrospectively reviewed over a four-year period. All rhBMP-2 treated patients were included. Control patients included all primary instrumented lumbar fusions. Endpoints included single observer recorded leg pain. There were 64 and 40 patients in the rhBMP-2 treated and control group respectively. Pre-operative demographics and diagnoses were similar. Inter-body cages were used equally. Three patients had non-mechanical leg pain in the control group versus eleven in the rhBMP-2 group of which 6 were revision surgeries. None of the control group had previous lumbar fusion (p< 0.05). Within the rhBMP-2 group, cage use was similar for leg pain (31%) and non-leg pain (29%).

Conclusion: In primary lumbar fusion surgery, there is no significant difference in post-operative MRI-identifiable mechanical leg pain between rhBMP-2 treated and non-treated groups. RhBMP-2 loaded cages do not increase the risk of leg pain. Recombinant hBMP-2 is safe to use in posterolateral lumbar surgery.

Conflicts of Interest: None

Source of Funding: None


S Mukhopadhyay S Batra S Kamath K Mukherjee S Ahuja

Incidence of pars defect associated with idiopathic scoliosis has been reported as 6% based on roentgenographic evaluation in previous studies. (Fisk et al, 1978). We aim to present our results in an MRI based study.

Methods: 229 patients of adolescent idiopathic scoliosis (AIS) who had an MRI scan over a period of three years (2006–2008), performed either as a preoperative investigation or due to other symptoms were reviewed. All MRI scans were reviewed by two experienced musculoskeletal radiology consultants independently.

Results: Among 229 patients 18 (7.86%) patients were found to have pars defect. Mean age-group of patients were (19 years, range-11–40). Male -5 (27.7%), female- 13(72.2%). There was varying severity of curve patterns, major thoracic curve-10, major lumbar curve-4, mild thoracic curve-3 and mild lumbar curve in one. Bilateral pars defect was noted in 14 (77.8%) patients.

Discussion: Previous studies (Fisk et al, 1978; Mau H 1977) have described the incidence of pars defect as approximately 6.2%. Recent studies have emphasized use of MRI to diagnose pars defect based on signal changes in the pedicle (Sairyo et al, 2009). Our study reveals the incidence of pars defect in AIS to be 7.86 % based on MRI diagnosis which does not seem to be different to previous roentgenographic studies.

Conflicts of Interest: none

Source of Funding: none


T Pincus A WoodCock S Vogel

Background and aims: Evidence-based recommendations for practitioners treating back pain emphasize adequate screening of work-related factors, and good communication with employers. It has been argued that getting all the stakeholders onside – including practitioners – could reduce sickness absence. However, expanding the role of clinicians to include exploration of occupational obstacles to recovery, and targeting these within the framework of clinical intervention is controversial. Private musculoskeletal practitioners (MPs) including physiotherapists, chiropractors and osteopaths treat a considerable section of those seeking care for low back pain (LBP). This study aimed to explore how private musculoskeletal practitioners view their role.

Method: A semi-structured interview was carried out with 15 physiotherapists, 16 chiropractors and 14 osteopaths. The interview schedule included questions about the relationship between work & health; communication with employers and GPs; strategies in returning/maintaining patients at work; and sick leave certification. Interviews were audio-taped & transcribed, and content analysis was carried out to extract themes. These were reviewed on a sample of interviews by another researcher, and independently reviewed against verbatim quotes by a third researcher.

Results: There was a consensus that work was in general good for psychological well being, but work-specific issues were also seen as threats to back pain. Most practitioners viewed patients who would not take time off work or moderate work-practices as the strongest threat for further problems. There was very limited communication with employers or GPs, but most practitioners gave advice about moderating work-duties.

In conclusion, private musculoskeletal practitioners explore work-related issues, and see return to work as an important treatment goal.

Conflict of Interest: None

Source of Funding: British Academy and BackCare


A Warren DG Mackarel K Wellington M Khatri

Aim: To evaluate patient satisfaction between telephone and traditional outpatient appointments following un-instrumented spinal surgery.

Material and Methods: The study was approved by the local audit committee. Fifty seven patients who underwent un-instrumented lumbar spinal micro-decompressive surgery in 2008 were identified from Bluespiers database and were contacted by telephone. A predesigned proforma was used to collect data. Ten patients had not yet had follow-up at the time of study and were excluded. Results of 47 patients were analysed and are described. No loss to follow up was encountered.

Results: Average age was 60 (Range 23 to 89 years) with 21 male (45%) and 26 female (55%). Majority (77%) of patients rated telephone follow-up as good or excellent. Average delay between scheduled appointment time and contact with the clinician was 47 minutes in traditional clinic. Majority (84%) of patients were contacted in time in telephonic clinic with minority (16%) experienced an average delay of 28 minutes. Majority (93%) of patients would recommend telephone follow up clinic and (70%) reported telephone follow-up was better or much better than traditional clinic. Reasons for preferring telephone follow-up included delay in the clinic, saving travel time and no need to find parking space. Six percent were dissatisfied with telephone clinic the reason being hearing impairment and desire to discuss their condition face-to-face.

Conclusion: Telephone follow-up clinic for un-instrumented spinal surgery appears to be a safe cost effective satisfactory alternative for the majority of patients. However traditional clinical follow up may be required for a proportion of patients.

Conflict of Interest: None

Source of Funding: None


P Khanna D Carnes

Background: Mind body therapies are being used increasingly to manage chronic musculoskeletal pain. We aimed to systematically review studies to explore the effectiveness of these mind-body therapies (MBTs).

Method: The following databases were searched MEDLINE, Psychinfo, AMED and CINAHL. Randomised controlled trials (RCTs), cohort studies, and case series studying adults with chronic musculoskeletal disorders were included. MBTs of interest were biofeedback, hypnosis, guided imagery, meditation, and progressive muscle relaxation. Papers of any language were included. Selection, data extraction and methodological evaluation of the studies were done independently. Narrative and meta-analyses were conducted where appropriate.

Results: The search identified 766 articles, 15 were selected for review, three were before and after studies, 12 were either RCTs or clinical controlled trials. The majority of the studies were of a low quality methodologically, with few participants. Fifteen of the studies reported MBTs reduced pain, this was significant for 7 studies post treatment and for five at follow up. MBTs generally had a positive effect on depression, quality of life, acceptance of pain, use of health care and medication. MBTs were as effective as active interventions such as CBT or education and superior to passive control groups.

Conclusion: MBTs may have the potential to reduce pain, depression and improve quality of life. There is not enough evidence to conclude that MBTs are more effective than standard medical care or which type of MBT is more effective. Data suggests that a bio-psychological approach may be beneficial in the treatment of chronic musculoskeletal conditions.

Conflicts of Interest: None

Source of Funding: Queen Mary University of London


C Gurbinder J Oni F Khan G Ampat

Introduction: An audit was undertaken to quantify patient satisfaction in the Orthopaedic Outpatient setting.

Materials and Methods: A 16 point questionnaire on a Likert scale of 1 to 5 was used. 216 consecutive questionnaires were distributed to patients attending the elective orthopaedic clinic during a three week period. The questionnaire collected details of sex, age, the grade of the health professional primarily assessing the patient in the clinic, administration of the appointment, welcome by reception staff, waiting room facilities, 7 questions pertaining to the care provided by the health professional primarily assessing the patient, 1 question regarding nurses and 2 regarding the overall service.

Results: Completed data was available only from 178 respondents (82.4%). There were 109 females and 69 males. 13 patients were under 20, 34 between 20 to 39, 61 between 40 to 60 and 70 over 60. 105 patients were seen by the Consultant, 49 by the Registrar, 14 by the Senior House Officer, 8 by a Physio Practitioner and 2 by an Associate Specialist. The mean score for questions 7 to 13 that pertained to the consultation with the health professional showed the following results. Associate Specialist 5.00, SHO 4.74, Consultant 4.70, Physio 4.68 and Registrar 4.63. The differences were not significant (P=0.017).

Conclusions: Our results show that patients are satisfied by being assessed even by Senior House Officers as long as normal NHS work practices are complied with.

Conflicts of Interest: None

Source of Funding: None


J Ashworth K Konstantinou KM Dunn

Background: Sciatica is an important cause of pain and disability but relatively few studies have looked at predictors of outcome in sciatica populations. Prognostic studies in non-specific low back pain are more common, but it has been suggested that the prognostic indicators for sciatica may be different. Our aim was to systematically review and describe the literature investigating the predictors of outcome in sciatica populations.

Methods: A systematic literature search of the databases (Medline, EMBASE, and CINAHL) and reference list of identified articles was conducted. Studies were included if they described subjects with sciatica, had a follow-up period of at least three months and measured outcomes including pain, disability, recovery, psychological outcomes or return to work. Methodological quality was assessed using a 15 item checklist.

Results: 596 papers were identified but only 12 met the criteria for inclusion. A combination of individual (e.g. gender, BMI), biomedical (e.g. size of disc prolapse, neurological deficit), social (e.g. job satisfaction, social status, manual labour) and psychological (distress, mental health) predictors of outcome were reported.

Conclusions: There are few high quality studies that have investigated prognostic factors associated with persistence of sciatic symptoms. Those identified explored a range of different factors, in a variety of settings and in subjects with variable duration of symptoms. Although the studies are difficult to interpret due to heterogeneity of the techniques used in analysis and presentation, they seem to suggest that clinical, occupational and individual factors might be more strongly associated with outcome than psychological factors in sciatica populations.

Conflicts of Interest: None

Funding: None


M West V Palial C Jakaraddi PSV Prasad G Ampat

Aim: This study aims to quantify pain relief and quality-of-life benefit from a diagnostic SIJ injection.

Methods: 50 consecutive patients were retrospectively recruited with unilateral low back pain, pain mapping compatible with a sacroiliac origin, tenderness over the SIJ, and no obvious source of pain in the lumbar spine. These were selected for a diagnostic SIJ injection. A structured questionnaire was completed both pre- and post-injection. Median patient age was 63. All patients were injected under fluoroscopic imaging with Triamcinolone 40mgs and 3mls Ropivacaine hydrochloride.

Results: Onset of lower back pain symptoms ranged from 1962 to 2007. 38 patients (76%) had some form of previous non-operative treatment. No patients had previous injection or surgery. 8 patients (16%) were smokers. 17 patients (34%) had a desk based job, 22 patients (44%) had a manual job, 7 patients (14%) had heavy manual jobs. 18 patients (36%) had sustained previous back injury. A visual assessment score was carried out for low back pain and pain in both legs, both pre- and post-injection. Overall, 16 patients (32%) reported no change in their symptoms, 7 (14%) reported worsening, but in 27 (54%) improvement was recorded. When considering the Oswestry Disability Index score, 18% reported no symptom change, 24% worsened and 58% improved.

Conclusion: History and physical examination can enter SIJ syndrome into the differential diagnosis, but cannot make a definitive diagnosis. Fluoroscopically guided diagnostic SIJ injection is the gold standard test for making the diagnosis whilst also conferring substantial pain relieve and quality-of-life benefit.

Conflicts of Interest: None

Source of Funding: None


B I Webster Hindmarsh G Ampat

Introduction: A survey was conducted among the personnel of Southport and Ormskirk Hospitals NHS Trust to determine the prevalence of spinal pain and the factors that could be related.

Materials and Methods: 200 questionnaires were distributed. Participation was voluntary. Details of sex, age, weight, smoking habits, previous accidents, compensation claims, details of work place, personal habits and presence of pain in the Neck, Thoracic spine, Lower Back and limbs were collected.

Results: Completed data was available only from 122 respondents (61%) who comprised of 16 HCAs, 42 Nurses, 5 OTs, 39 Physiotherapists 15 Theatre Practitioners and 5 others. The average age was 39.5 years. 92 (75.4%) had pain in at least one spinal region. 30 (24.6%) had no spinal pain. 35 (28.7%) had pain in the all the three regions of the spine. 83 of the respondents had Lower back followed by 53 having neck pain. 51 had of mid back pain. 15 of the 39 physiotherapists (38.5%) reported that they had no pain in any region of the spine. This contrasted with the Occupational Therapists in whom none of the 5 (0%) reported a pain free spine. There was no correlation between pain and Age, Sex or Weight. Twenty (16.4%) respondents smoked and the average spinal pain among smokers was 8.45 whilst that of non smokers was 5.03. (p< 0.05).

Conclusions: Among the groups tested the physiotherapists seemed to have healthy backs. Our results from a small survey show a clear correlation between smoking and back pain. These results seem to suggest that health promotion to decrease back pain should promote quitting smoking.

Conflicts of Interest: None

Source of Funding: None


M West PSV Prasad G Ampat

We would like to present a rare case report describing a case in which new-onset tonic-clonic seizures occurred following an unintentional durotomy during lumbar discectomy and decompression. Unintentional durotomy is a frequent complication of spinal surgical procedures, with a rate as high as 17%. To our knowledge a case of new onset epilepsy has never been reported in the literature. Although dural rupture during surgery and CSF hypovolemia are thought to be the main contributing factors, one can postulate on the effects of anti-psychiatirc medication with epileptogenic properties. Amisulpride and Olanzapine can lower seizure threshold and therefore should be used with caution in patients previously diagnosed with epilepsy. However manufacturers do not state that in cases were the seizure threshold is already lowered by CSF hypotension, new onset epilepsy might be commoner. Finally, strong caution and aggressive post-operative monitoring is advised for patients with CSF hypotension in combination with possible eplieptogenic medication.

Conflict of Interest: None

Source of Funding: None


Geoffroy Nourissat Amadou Diop Nathalie Maurel Marjolaine Gosset Colette Salvat Francis Berenbaum

Purpose of the study: Irrespective of the technique used, the average rate of bone-tendon healing after rotator cuff repair is about 50% One of the reasons is the poor vitality of the tissues implicated in repair, particularly progressive destruction of the enthesis. Using the rat Achilles tendon, we destroyed the enthesis mechanically then repaired it with and without local injection of chondrocytes in order to study the effect of cell therapy on healing phenomena.

Material and method: Sixty 3-month-old Wistar rats were operated on under general anaesthesia to detach the Achilles tendon and destroy the enthesis. In the first group (RI), the tendon was reinserted via a transosseous tunnel using a 4/0 non absorbable knitted thread. In the second group (RIC), joint chondrocytes, harvested from 4-day-old rats were injected locally during the same repair procedure. Animals were sacrificed every 15 days (n=15 per group) for a biomechanical and histology study.

Results: In group RI, the non-healing rate was 50% versus 33% in group RIC; the difference was not significant (n=0.3). Tear resistance was increased significantly at 45 days in the RC group (p=0.04). The histology study showed a statistically significant development of a neoenthesis in the RIC group (p< 0.05), which was not observed in the RI group.

Discussion: This animal model is valid for exploring rotator cuff healing with a spontaneous rate of healing to the order of 50%. Addition of chondrocytes during the surgical repair induces the production of an enthesis and increases the healing rate 50% and the value of the different biomechanical parameters at 30 days, with a statistically significant difference at 45 days.


Bruno Barbe Philippe Clavert Cyril Penz Yvan Le Coniat Jean-Francois Kempf

Purpose of the study: Little work has been done to assess outcome of rotator cuff tear repair in young adults aged less than 40 years. The purpose of our study was to assess the clinical and anatomic outcomes in a continuous series of arthroscopic rotator cuff repairs performed in patients aged less than 40 years.

Material and method: This was a retrospective analysis (2004–2007) of 15 young patients (age 18–39 years, mean 32.7 years) with rotator cuff tears confirmed on the arthroscan. All tears were repaired arthroscopically using the same reinsertion technique with anchors. Patients underwent bilateral assessment (SSV, Constant) at at least 12 months follow-up. A control imaging with injection (arthroscan or arthroMRI) was available in 12 of 15 patients.

Results: The series included 7 female and 8 male patients, 13 right and 2 left shoulders; 14 of 15 shoulders were on the dominant side. The time from symptom onset to surgery was 26 months on average. Patients were reviewed at mean 31 months follow-up. Preoperative range of motion was preserved in all patients. The mean preoperative Constant score was 55.5 on the operated side and 91.4 on the other side. The preoperative arthroscan demonstrated partial deep tears of the supraspinatus or infraspinatus in 5 patients with a posterosuperior impingement. The ten other shoulders exhibited full thickness tears of the supraspinatus. At last follow-up, the mean Constant score was 77.2 (range 44–90) with significant improvement of all partial scores except force. Patients resumed their former occupational activities at mean 8 months (range 1–36); resumption of sports activities occurred during the 7th month. Subjective satisfaction rate was 81.7%. Postoperative imaging with injection showed a healed cuff in 83% of the shoulders reviewed (10/12).

Discussion: Rotator cuff tears are exceptional in young subjects aged less than 40 years; there is considerable potential for worsening. Outcome after rotator cuff repair is very age dependent. It is important to diagnose these tears early to enable early repair; the anatomic results are good and persistent in younger patients.


Matthias Zumstein Virginie Lesbats Christophe Trojani Pascal Boileau

Purpose of the study: Platelet rich fibrin (PRF) favours proliferation of tenocytes and synthesis of extracellular matrix. The purpose of this study was to demonstrate the technical feasibility of adding a PRF envelope during arthroscopic rotator cuff repair to favour short-term vascularisation of the tendon-trochiter zone vascularization.

Material and method: Twenty patients aged over 55 years with a posterosuperior rotator cuff tear were included in this prospective randomized controlled study. The double strand technique was used for all patients. Patients were selected at random for insertion of a PRF envelope between the tendon and the trochiter. There were thus two groups of ten patients. The SSV, SST, VAS and Constant scores were noted. Vascularization was assessed with Power Doppler ultrasound at 6 weeks and 3 months by an independent operator unaware of the study group.

Results: There were no complications during or after the operations. Postoperatively, all patients increased their SSV, SST, VAS and Constant scores significantly. Vascularization of the tendon-trochiter zone, as assessed by Power Doppler, was significantly higher in the PRF group at 6 weeks. It was unchanged in the two groups at 3 months.

Discussion: Arthroscopic rotator cuff repair with adjunction of a PRF envelope is technically feasible and increases vascularizaton of the tendon-trochiter zone at 6 weeks.

Conclusion: PRF can improve the tendon healing rate for rotator cuff tears.


Laurent Nové-Josserand Arnaud Godenèche Lionel Neyton Jean-Pierre Liotard Eric Noël Gilles Walch

Purpose of the study: Many rotator cuff tears occur in the context of a work accident or an occupational disease (schedule 57-A in the French occupational disease nomenclature). This context is a negative factor for outcome although diverse opinions are expressed in the literature. We wanted to study the occupational outcome of operated patients after rotator cuff repairs and to determine what factors affect this outcome.

Material and method: From 2000 to 2005, 1155 patients underwent rotator cuff repair performed by the same operator. The context was an occupational context (schedule 57-A) in one quarter of these patients (n=290, 25.1%). Among these, 87.6% (n=254) responded to a mail questionnaire. In all 262 shoulders were included in this series (8 bilateral cases). Male gender predominated (72%) and 69% of the tears were in the right shoulder. Mean patient age was 50.53±6.4 years. In this series, 67% of the tears were related to a work accident and 33% to an occupational disease. The patients were salaried workers (75.2%), independent craftsmen (12.6%), and civil servants (11.8%). The occupational category was heavy manual labour (68.3%), light manual labour (25.5%), non manual occupation (6.1%). The injury involved one tendon in 64.1%, two tendons in 28.2% and three tendons in 7.6%. Classical open repair was performed for 70.6%), mini-open repair for 9.2%, and arthroscopic repair for 20.2%.

Results: Patients resumed their occupational activity in 59.64% of the cases (mean age 48±0.8 years); 40.45% did not resume their occupational activity (mean age 54±5.3 years). Excepting cases of retirement or interruption related to another medical condition, the shoulder was the reason for not resuming work in 16% of patients. Young age (p=0.0005) and type of surgery (open procedure p=0.0004) were factors favouring resumption of occupational activity while gender, occupational category and type of injury had no effect. The duration of sick leave (full time) depended on the occupational category (p=0.004) and somewhat on gender, age, occupational situation, work accident or occupational disease, and type of surgery/

Conclusion: Work accidents or occupational disease were not synonymous with failure of rotator cuff repair. Age was the leading prognostic factor.


Barbara Melis Michael DeFranco Gilles Walch

Purpose of the study: Fatty infiltration and atrophy of rotator cuff muscles is an important prognostic factor for anatomic healing and function after repair. The purpose of this study was to analyse factors influencing the development and progression of the supraspinatus muscle and to search for correlation between infiltration and atrophy.

Material and method: Preoperative arthroscans and MRI series for 1688 patients with rotator cuff tears were reviewed. We searched for correlations between fatty infiltration of the supraspinatus muscle and gender, age at imaging, size of the tear, onset (trauma or not), and time from symptom onset to imaging. Fatty infiltration was noted according to the Goutallier classification and on the MRI using the classification adapted by Fuchs. For the statistical analysis, fatty infiltration was considered minor for grades 0 and 1, moderate for grade 2 and severe for grades 3 and 4. Muscle atrophy was assessed using the tangent sign.

Results: Fatty infiltration of the supraspinatus increased significantly with the size of the tendon tear (p< 0.0005), time from symptom onset to imaging (lp< 0.0005) and patient age (p< 0.0005). Atrophy increased with number of torn tendons, positive tangent sign was correlated with the grade of fatty infiltration of the supraspinatus (p< 0.0005) and the infraspinatus (p< 0.0005). Moderate and severe fatty infiltration developed a mean 3 and 5 years, respectively, after symptom onset.

Discussion: Surgical treatment should be undertaken before the appearance of moderate (grade 2) fatty infiltration and atrophy (positive tangent sign).

Conclusion: Moderate fatty infiltration of the supraspinatus develops on average three years after onset of symptoms.


Gilles Walch John Lunn Laurent Nové-Josserand Jean-Pierre Liotard Barbara Mélis

Purpose of the study: Four elements differentiate myotendinous tears of the infraspinatus from other rotator cuff tears: the tendon insertion on the trochiter and the joint capsule are spared; the onset in characterized by intense muscle oedema followed at 6 to 12 months by severe and definitive fatty degeneration.

Material and method: Fifty-nine myotendinous tears of the infraspinatus were collected prospectively from 1993 to 2007. Female gender predominated (58%); trauma was noted at onset in 22% of the shoulders and the mean age of discovery was 48.9 years. Twenty-nine shoulders were seen at the acute phase with significant muscle oedema recognized on the MRI T2 Fat Sat sequence. A second group of 30 patients had grade 4 fatty infiltration of the infraspinatus without full thickness cuff tears. The EMG was available for 23 shoulders and was normal in all, ruling out a neurological cause. Associated lesions of the supraspinatus and infraspinatus tendons were: tendon calcification (61%) and partial tears at the acute phase (21%) and chronic phase (70%) suggesting a degenerative cause.

Results: Twenty-four patients underwent surgery and 35 had a medical treatment. At mean 46 months follow-up (range 12–125) the Constant score improved from 51.7 to 69.4 points (p< 0.0001). There was no different statistically between the operated and non-operated patients (p=0.325). All patients seen at the acute phase of the oedema progressed to complete grade 4 fatty degeneration of the muscle, irrespective of the treatment delivered.

Discussion: Early diagnosis of this lesion can be achieved with T2 Fat Sat MRI sequences. Arthroscopic repair to tighten the infraspinatus muscle could avoid the irremediable degeneration with total loss of muscle function.


Philippe Valenti Jean Kany Sébastian Ferrière Michel Semaan

Purpose of the study: The purpose of this work was to report the clinical outcomes observed after great pectoral transfer (clavicular head in 8 cases and sterna head in 7) behind the coracoids for irreparable subscapular tears.

Material and method: This was a retrospective analysis of 15 patients, mean age 57 years, with retracted subscapular tears with fatty degeneration grade 3 or greater, associated with a supspinatus tear for 12 cases. The Constant score was not pre and postoperatively. The lift-off test was positive in all patients. The clavicular head (n=8) and the sterna head (n=7) were positioned under the coracoids and fixed with anchors in the trochin using the double row technique. Biceps tenodesis was associated in 12 cases. Immobilisation was maintained for six weeks in neutral rotation with passive mobilization immediately postop and active rehabilitation after the sixth week.

Results: At mean 24 months follow-up (range 12–50), nine patients were very satisfied, three were satisfied, and three were disappointed; one patient had revision with a reverse prosthesis due to anteroposterior instability; one patient developed an infection after a haematoma and retained an elevation deficit and a painful shoulder. The gain was 11 points (2.66 to 13.6 ([p< 0.001]) for pain and 4.5 points (3.2 to 7.7 [p< 0.001]) for force. The gain was non significant for active elevation (7 points) and external rotation (6 points). The lift-off test was negative in 11 of the 15 shoulders. There was no significant difference between the two pectoral heads. This series is limited by the small number of shoulders.

Discussion: Greater pectoral transfer for unreparable tears of the subscapularis improves force and reduces pain. However, compared with data in the literature, outcome is not different if the entire muscle is used or if only the sterna or clavicular heads are used, whether inserted anteriorly or posteriorly on the coracoids.


Barbara Melis Michael DeFranco Gilles Walch

Purpose of the study: Data concerning the teres minor in the context of rotator cuff tears is scarce despite the fact that this muscle plays a crucial role in the event of an infraspinaus tear. The purpose of this study was to analyse the computed tomography and magnetic resonance images of the teres minor muscle in rotator cuff tears.

Material and method: The aspect of the teres minor muscle was studied in 1624 shoulders with rotator cuff tears. The axial and sagittal CT or MRI aspect was noted as normal, hypertrophic, atrophic or absent (Walch classification). We searched for correlations with the tendon torn, tear mechanism (trauma, degeneration, mixed), gender, dominance, time to imaging, age at imaging, and fatty infiltration of the supraspinatus, infraspinatus and subscapularis.

Results: The teres minor was noted normal in 90.9% of the shoulder, hypertrophic in 5.2%, atrophic in 3.2% and absent in 0.2%. The type of cuff tear had a significant impact (p< 0.0005). Regarding the aspect of the teres minor muscle, the highest percentages were as follows: normal for isolated supraspinatus tears, hypertrophic for supraspinatus and subscapularis tears, atrophic for posterosuperior (supraspinatus, infraspinatus ± teres minor) tears and absent for massive tears involving the supraspinatus, the infraspinatus ± the subscapularis (p< 0.0005). The correlation was statistically significant between the aspect of the teres minor and the grade of fatty infiltration of the infraspinatus (p< 0.0005) and the subscapularis (p< 0.0005).

Discussion: The aspect of an atrophic or absent teres minor, which correlates with the trumpet sign in massive tears, was only found in 3.5% of the tears. There would thus be few indications for latissimus dorsi transfer to restore active external rotation.


Yves Stiglitz Olivier Gosselin François Sirveaux Daniel Molé

Purpose of the study: Arthroscopic repair of rotator cuff tears is a painful technique. We conducted a randomized controlled trial to analyze prospectively the level of postoperative pain after this procedure and to assess the efficacy of three anti-pain techniques.

Material and method: This prospective randomized study included 140 patients attending two centres specialized in shoulder surgery who underwent arthroscopic rotator cuff repair from January to November 2008. Preoperatively, patients were assigned to three anti-pain techniques: interscalenic catheter (KTIS) (n=44 patients), subacromial catheter (KTSA) (n=64 patients), unique subacromial injection of 2% ropivacaine (INJ) (n=32 patients). The procedure was performed under general anaesthesia in all cases. Criteria used to evaluate the efficacy of the anti-pain techniques were: pain as assessed by a visual analogue scale (VAS) the day before operation to the 30th postoperative day; daily consumption and total dose of opiates; subjective satisfaction with pain management assessed on day 30.

Results: The pain profile was the same as demonstrated last year with a painful displacement on day 1 and progressive decline in pain through day 30 when the pain level was lower than preoperatively. Two risk factors were noted: isolated distal tears of the supraspinatus and concomitant acromioplasty. On day 0, the VAS was ≤ 1.7 in the KTIS group versus 3.6 and 3.5 respectively in the KTSA and INJ groups (p< 0.05). On day 1, the respective values were 3.1, 3.5 and 3.8 (NS). On day 2 and beyond, there was no difference between the three groups. Overall morphine consumption on day 0 was 10.8 mg in the INJ group versus 6.9 and 2.1 mg in the KTSA and KTIS groups, with a significant difference between the INJ and the KTIS groups. There was no difference beyond day 1. Patient satisfaction with pain management during the first 30 postoperative days reached 94.4, 82.9 and 84% respectively for INJ, KTIS and KTSA, with no statistically significant difference between the groups.

Conclusion: The interscalenic catheter technique is more effective than the two other techniques. The subacromial catheter is not better than a single injection of local anaesthetic and is associated with greater risk, suggesting its use should be revisited.


Alain Masquelet Thierry Bégué Didier Hannouche

Purpose of the study: Classically, bone grafts are harvested from the iliac crests which can provide a limited volume of graft material. Using the reaming product might help spare iliac bone.

Material and method: A variable head RIA device (reaming, irrigation, aspiration) was used over the last year for ten patients who presented partial or segmental bone loss. The bone graft was constructed exclusively with the reaming produce following membrane induction using a cement scaffold. The tibia was reconstructed in nine cases and the humerus in one. Bone loss was 6 cm on average.

Results: The reconstruction healed in six cases within a mean delay of 6 months; the 4 other cases are under assessment. Complementary bone was necessary to achieve healing in one case. There were no complications involving the donor site excepting transient pain at the point of insertion.

Discussion: In this series associating an induced membrane and reaming produce, the time to healing appeared to be shorter than with cancellous iliac bone. The smaller size of the fragment may be a determining factor.

Conclusion: Reaming products collected from medullary cavities of the long bones can be used for reconstruction of bone loss.


Jean-Christian Balestro Christophe Trojani Gisèle Daideri Pascal Boileau

Purpose of the study: Palliative treatment for unreparable rotator cuff tears by intra-articular resection of the long head of the biceps provides demonstrated satisfactory results. We hypothesized that associated acromioplasty could be deleterious.

Material and method: We conducted a case-control study comparing 24 tenotomies or tenodeses of the long head of the biceps with 24 tenotomies or tenodeses of the long head of the biceps associated with acromioplasty. All patients had an unreparable tear of the rotator cuff. Full-thickness tear of the subscapularis or Hamada and Fukuda radiological stage 3 or 4 tear were exclusion criteria. The two groups were matched for weighted Constant score, Hamada and Fukuda stage, type of tear of the infraspinatus and subscapularis, overall fatty infiltration grade, and follow-up. After the physical examination, we compared the four items of the Constant score, the absolute and weighted score, active anterior elevation, pain score on a visual analogue scale (VAS), and the subjective shoulder score. All patients were examined by a clinician unaware of the group at last follow-up (mean 51 months).

Results: The two groups were comparable preoperatively except for the fatty infiltration index which was higher in the acromioplasty group. At 51 months follow-up, active anterior elevation was statistically lower in the acromioplasty group (145 versus 170). The absolute and weighted Constant scores were lower in the acromioplasty group (p< 0.05). There was no difference for pain and the subjective shoulder score (67 versus 71). Four patients in the acromioplasty group required revision total shoulder arthroplasty versus two in the group without acromioplasty.

Discussion: Association of acromioplasty with intra-articular resection of the long head of the biceps for palliative treatment of unreparable rotator cuff tears is deleterious for elevation and reduces overall shoulder function. Even though acromioplasty provides good short-term results for average-sized tears, outcome is less satisfactory for massive tears and deteriorates over time. In addition, as described by Wiley, acromioplasty can induce a pseudoparalytic shoulder in patients with unreparable tears.


Luc Favard Julien Berhouet Philippe Collin Tewfik Benkalfate Christophe Le Du Fabrice Duparc Olivier Courage

Purpose of the study: Little is known about the clinical profile of patients aged less than 65 years who present a large or massive rotator cuff tear. We hypothesized that this clinical profile depends on the type of tear.

Material and method: This was a prospective descriptive multicentric study over a period of six months which included 112 patients aged less than 65 years, 66 men and 46 women, mean age 56.3 years (range 35–65) who had a large or massive rotator cuff tear. The Constant score and active and passive range of motion, subacromial height and fatty infiltration according to the Goutallier classification were noted. Patients were divided into four classes according to deficit in active elevation and external rotation: class A (n=55, no deficit), class B (n=19, deficient elevation alone), class C (n=28, deficient external rotation alone), class C (n=10, deficient elevation and external rotation).

Results: These classes were not significantly different for age, sex-ratio, duration of symptoms, or presence of subscapular involvement. Trauma was involved more often in patients in class B and class D. The mean absolute Constant score was significantly lower in patients in class B (30.2) or D (23.5) than in class A (53.3) or C (44.7). The subacromial space was significantly narrower in group D (5 mm) than in the other groups. Fatty infiltration of the infraspinatus scores > II was significantly more common in groups C and D. Severe fatty degeneration of the subscapular (> II) was found in only eight shoulders and was not correlated with defective active elevation.

Discussion: This study demonstrates that deficient external rotation is correlated with the type of tear but has little impact on the Constant score. Conversely, patients with deficient active elevation have a lower Constant score but do not exhibit characteristically different tears than patients without deficient active elevation. Thus, the management scheme should be no different in patients with deficient elevation than in patients with out deficient elevation, excepting cases with a major lesion of the subscapularis.


Romain Gérard Eric Stindel Grégory Moineau Dominique Le Nen Christian Lefèvre

Purpose of the study: The purpose of this retrospective work was to analyse a series of ten patients (11 osteotomies) who underwent closed rotation osteotomy of the femur performed with an endomedullary saw and stabilized with a centromedullar locked nail. We identified the proper indications, technical aspects, clinical and radiological outcome and describe the complications of this surgical technique.

Material and method: The 11 osteotomies were performed in ten patients from January 1999 to July 2007 for post-trauma rotation defects or congenital deformity. On average the rotation defect was 33.5 (range 24–52), mainly internal rotation (10 cases versus 1 with external rotation). One female patient required a bilateral procedure in a context of congenital bilateral trochlea dysplasia. For two other patients the corrective osteotomy was associated with a lengthening procedure performed during the same operative time (totally closed operation). Clinical and radiological follow-up was available to 4 years 9 months on average (range 26–104 months). The angle corrections were determined on bone tomographs.

Results: Ten of the 11 osteotomies yielded correction to ±4° physiological values (or controlateral values if the other side was healthy) for anteversion of the femoral neck. There were no infections (bone, joint, skin, soft tissue) and not late healing or non-union. There was one transient neurological complication involving the pudendal nerve during a rotation-lengthening procedure and one bilateral fracture of the femur during a bilateral osteotomy. All patients healed within 3 to 5 months. Subjective outcome was satisfactory very satisfactory for 8 of 9 patients (one lost to follow-up) in terms of functional recovery and aesthetic aspect of the scars.

Discussion: The closed procedure for rotation osteotomy of the adult femur is a reliable, effective, safe and reproducible technique for the correction of rotation defects of the femur resulting from trauma or congenital disorders. These results can be obtained only with rigorous technique requiring experience and skill with centromedullary nailing.


Luc Favard Julien Berhouet Michel Colmar Julien Richou Eric Boukobza Alexandre Sonnard Dominique Huguet Olivier Courage

Purpose of the study: For patients aged less than 65 years who have a large rotator cuff tear, potential solutions include anatomic repair, palliative treatment, non-anatomic repair with flaps or cuff prosthesis, and reversed prosthesis. The later solution is not recommended at this age and anatomic repair is not always possible. In this situation, what is best, palliative treatment or flap or prosthesis repair?

Material and method: This retrospective multicentric study included 142 patients, 74 men and 68 women with a large or massive cuff tear. Palliative treatment (group A) involved acromioplasty (n=48) associated as needed with a biceps procedure and partial repair (n=41). Non-anatomic repair (group B) included supra-spinatous translation (n=16), deltoid flaps (n=22), and cuff prostheses (n=15). Preoperatively, the two groups were not statistically different for acromiohumeral height (AH, 6 mm in group A versus 7.5 mm in group B) and percent of fatty infiltration of the infraspinatus > II (55% in group A versus 26% in group B). The Constant score, active and passive range of motion, gain in elevation and external rotation were noted.

Results: Mean follow-up was 74 months in group A and 90 months in group B; the Constant score was 64 and 65, active elevation 145 and 147 and external rotation 17 and 26 respectively. The two groups were not significantly different. For patients with deficient elevation (n=46), the gain was 62 without any difference between the two groups. For patients with deficient external rotation (n=37), the gain was nil in both groups.

Discussion: Although group A had a more severe condition than group B (narrower AH and more advanced fatty degeneration, the final outcome as assessed by the Constant score and range of motion was similar. Both groups recovered active elevation well, but not external rotation. Nevertheless, there were no cases of latissimus dorsi transfer in this series. Repair with a deltoid flap, supraspinatus translation, or cuff prosthesis does not appear to add any supplementary benefit despite the more aggressive surgery.


Nicolas Paris Olivier Roche Nicolas Vendemmia Franck Wein François Sirveaux Daniel Molé

Purpose of the study: There are several goals for the treatment of septic nonunion of the leg: control the infection, achieve healing, preserve function. The purpose of this work was to report the results obtained with a two-phase technique using a cement spacer.

Material and method: From 1994 to 2007, 27 patients were treated for a septic nonunion of the tibia (19 proven, 8 suspected). There were 22 women and 5 men, mean age 39 years (range 16–66). The first phase of the surgical technique involved “cancerological” cleaning and insertion of an antibiotic cement spacer. Osteosynthesis was performed if necessary. Antibiotics were adapted to sample results. The second phase involved an autologous bone graft with osteosynthesis after biological markers had returned to normal and an antibiotic window. Antibiotics were then discontinued if samples were negative. Patients were reviewed with physical examination, radiology, and laboratory tests at one year.

Results: Mean follow-up was 4 years (range 1–11). At the first phase, mean bone defect after cleaning was 5 cm (range 3–8); osteosynthesis procedures were required for 22 patients (81.5%), mainly with plate fixation. Mean time to the second phase was 4 months (range 1.5–22). At the second phase, bone loss was filled with isolated bone fragments (44%) or associated with a tricortical graft (52%) or a plate nail combination (37%). Bacteriological samples were negative for 25 patients after the second phase. Six patients required surgical revision for recurrent aseptic non-union (22%).

Discussion: All patients healed at mean one year with a tolerable misalignment in 37%. At last follow-up there were no cases of infection. Nineteen patients had residual stiffness of the ankle or knee but 80% had resumed their sports activities and 85% their occupational activities.

Conclusion: A two-phase surgical treatment of septic non-union of the leg is effective. We were able o achieve cure of the infection in all patients with per primam healing in 78% in addition to an acceptable functional outcome. The spacer offers the advantage of preparing a bed for the graft and preserving autonomy between the two phases.


Julien Richou Bernard Sénécail

Purpose of the study: Covering cutaneous tissue loss of the distal quarter of the leg and ankle remains a difficult surgical challenge. We report our experience with a new lateral hemisoleus island flap with a fibular pedicle specifically adapted for large-sized defects.

Material and method: Preliminary anatomic work on 15 injected legs demonstrated that:

the dimensions of the muscular part of the lateral head of the soleus measures on average 218 mm (range 160–270) in length and 73 mm (range 58–95) in width, sufficient for large “tailored” flaps;

a main pedicle arises constantly from the fibular artery to supply the lateral hemi-soleus in addition to, on average, three secondary pedicles;

the distal pivot point, corresponding to the branch perforating the fibular enables not only cover for the ankle, but also the foot reaching the metatarsal heads.

Results: Three patients treated with success are presented. The advantages of the technique are large muscle volume, safe vascular supply and significant mobility. Drawbacks include sacrifice of the fibular artery and difficult dissection of the fibular pedicle. Preoperative precautions are indispensable: arteriography, exclusion of contusion cases affecting the muscle masses or compartment syndrome.

Discussion: The lateral hemi-soleus flap can be a useful therapeutic option for major tissue loss on the distal quarter of the leg, the ankle, or even the foot. It is an attractive alternative to free flaps, the only other solution for large defects.


Cédric Bouquet Louis-Étienne Gayet Hamid Hamcha Pierre Pries

Purpose of the study: This was a retrospective analysis of patients with bone loss subsequent to an open leg fracture. Negative pressure therapy was applied in 42 cases over a period of 47 months.

Material and method: Our strategy was designed around the goal of secondary rather than emergency cover, after preparation of the wound bed with NPWT. The time from the first surgical care to NPWT was 23.38 days on average. Mean duration of NPWT was 21.19 days.

Results: After NPWT, gain in wound surface was 18.09% on average. The gain was nil for 52.38% of the patients, positive for 47.62% and exceptional for 4.76%. 100% of the wounds analysed developed a regular border which prepared a bed for a graft or flap without decreasing the depth of the wound. NPWT enabled all patients to reach the set objective: directed healing in 19%, skin graft in 48%, flap in 33%. The objective were achieved for 66% of patients, exceeded, partially achieved for 14% and not reached for 10%.

Discussion: We conclude that NPWT is an excellent way to wait for slow healing after cleaning. It stimulates formation of a granulation tissue, favours the development of regular borders, and cleans the wound before definitive surgical treatment. Thus whether achieved with a flap, a graft or directed healing, the final cover is thus minimised. NPWT can also reduce the risk of infection during the initial phase since the wound is drained and outside contamination is limited by the air-tight dressing. Cost remains a limitation even though certain studies have found equivalent cost with conventional dressings, often related to use of lower cost “homemade” dressings.


Loïc Potier Coumba Diouf Niang Momar Sene Elimane Mbaye Moussa Faye

Purpose of the study: In sub-Sahara Africa, classical directed wound healing followed by a skin graft remains an important part of the treatment of open fractures with tissue loss. The purpose of his prospective cohort study was to assess a continuous series of muscle and fasciocutanous flaps, focusing on their contribution to the reduction of post-trauma focal infection.

Material and method: From September 2007, patients with an open fracture of the leg were studied prospectively. After emergency debridement and stabilisation, open fracture foci were covered with a muscle or fasciocutaneous flap secondarily. Twenty-five patients received 29 flap covers of the lower limb (21 fasciocutaneous and 8 muscle) from October 26, 2007 to February 24, 2009. The Gustillo-Anderson and Catagni classification was noted. Evaluation criteria were successful cover of the bone and presence or not of focal osteitis at last follow-up.

Results: Delay to admission was less than 4 hours in eight patients (30%). Time to primary surgery was greater than 4 h in 90% of patients. Time to flap cover was 29 days for the 18 first-intention flaps; 60 days for three repeat flaps; 217 days for seven second intention flaps. Inaugural colonisation of the fracture site was confirmed in 20 of the 25 patients. Complete necrosis of the flap occurred in four patients (16%) (two muscle flaps revised with fasciocutaneous flaps) and partial necrosis in two others. Successful primary cover was achieved with 12 flaps, and secondary cover in ten others after a new flap (n=3), directed healing, or complementary skin graft. At eight months, two patients had residual focal infection.

Discussion: This series exhibited particularly long delay to primary surgical care and a high level of inaugural focal infections.

Conclusion: Superficial tissue infection around the exposed fracture site should ideally be controlled within six weeks to prevent progression to osteitis. After complete excision of the irremediably damaged tissue, early cover with a flap closes the exogenous infection portal and prepares the wound for secondary bone reconstruction.


François Lintz Jean-Alain Colombier Joseph Letenneur François Gouin

Purpose of the study: Acute compartment syndrome of the leg can lead to serious sequelae affecting patient autonomy. Retractile postischemic fibrosis leads to various deformities of the ankle and foot from simple claw toe to complex multidirectional dislocations. Aggressive surgery, or even amputation, may be needed to save soft tissue. Data are scarce on management practices for these deformities. We present a long-term follow-up.

Material and method: From 1981 to 2006, 150 patients with a compartment syndrome of the leg were managed in our unit. Ten of these patients later required repeated surgery directly related to the sequelae of the compartment syndrome affecting the foot and ankle. These patients were followed in our unit. Personal data, as well as potential risk factors and sequelae were noted. Data were analysed and compared with reports in the literature.

Results: For nine of the ten patients, the initial diagnosis was established late, for seven, more than 24 hours after onset. The anterior and lateral compartments were involved (10/10 and 9/10) and less often the deep posterior compartment (3/10), motor deficit (3/10) and sensorial deficit (5/10) of the tibial nerve. The deep posterior loge was the cause of late equine deformity in eight patients. Functional outcome was good in eight patients after secondary surgery. For the other two cases, leg amputation was the only solution.

Discussion: Complicated acute compartment syndrome of the leg most commonly involves the anterior and anterolateral compartments. Conversely, the posterior compartment is implicated in the development of invalidating sequelae. We analysed the different procedures used in the literature for managing these sequelae and established a classification. Effective treatment of the foot and ankle affected by a late postischemic syndrome depends on a rigorous surgical strategy taking into account the multidirectional and multifactorial aspects of the resulting deformity. Prevention nevertheless remains the most effective treatment, both by early initial aponeurotomy and by prevention of the secondary deformity.


Stéphane Levante Nasser Mebtouche Véronique Molina

Purpose of the study: The sural flap with a distal pedicle is a commonly used flap for ankle or foot cover; it has been described as easy to achieve, versatile and reliable. Following several personal failures, we attempted to analyse the principle factors of unfavourable outcome and to determine the precise role for this flap in distal cover of the lower limb.

Material and method: We retrospectively analysed a series of 25 sural flaps with a distal pedicle performed by one operator among a series of 55 ankle and foot flaps. Outcome was assessed as complete flap survival; even partial necrosis was noted. Factors examined included patient age, context, localization and surgical factors.

Results: Eight flaps necrosed (7 partial and 1 total) leading to amputation (32% complications). Flaps with partial necrosis nevertheless all healed after repair.

Discussion: This series had a high failure rate, like earlier reports in the literature. Most of the necrotic flaps were observed in older patients with vulnerable tissues. Conversely, the size of the flap or the localization of the recipient site did not appear to affect outcome; there was no apparent learning curve. The harvesting technique and the difficulties presented by anatomic variations are recalled. Treatment of the pedicle is important but cannot explain all of the failures. Why the distal sural flap should be chosen among the different flaps available for the lower limb depending on the site and situation is not clear. Technical elements, such as two-phase harvesting can be helpful, but for us do not appear to improve the survival of this flap whose outcome remains difficult to predict.


Rachid Chafik Mohamed Madhar Abderrahim El bouanani Mansouri Nadia Saidi Halim Tarik Fikry

Purpose of the study: Wounds of the calcaneal tendon are common, but less well documented compared with tears of the same tendon. We performed a retrospective analysis of the epidemiological, therapeutic and prognostic features of this injury.

Material and method: The series included 70 patients collected from 1992 to 2002; 56 male and 14 female. Mean age was 22 years (range 4–70 years). The right ankle was involved in 42 cases. Causes were broken glass injury (44%), automobile accidents (22%), aggressions (18%) and motorcycle wheel injuries (10%).

Results: The diagnosis was obvious at admission. A surgical exploration was systematic to determine the partial or complete nature of the injury. Surgical treatment involved tendon repair with a cage or frame in 65 patients. A plantar plasty was needed in three patients. Bosworth tendinoplasty was performed in two other patients. The three cases with skin loss were treated by directed wound healing (n=2) and MacFarlane flap (n=1). Postoperative complications were: infection (n=11) and functional (n=10, shoe conflict). The scar remained disgraceful in 20 patients. Outcome was good or very good according to the Schmitt criteria in 92% of patients.

Discussion: Wounds of the calcaneal tendon are common, and are generally observed in young male patients. The diagnosis is clinical. The goal of treatment, either by simple suture or by pasty, is to restore normal ankle function. Because of the risk of infection, as well as the risk of a poorly healed scar preventing proper use of shoes, any surgical procedure must be as minimally traumatic as possible and performed under rigorous conditions. Adequate immobilisation and rehabilitation are required for good outcome. The prognosis is generally good.


Philippe Chiron Jean-Michel Laffosse François Loïc-Paumier Nicolas Bonnevialle

Purpose of the study: Transadductor approaches to the hip joint have been described in the spastic child. Ludl-off as well as Ferguson pass behind the short adductor and the pectineus, a narrow route with a risk of injuring the obturator nerve. We describe a simple minimally invasive approach.

Material and method: The incision is made with the hip in the flexion, external rotation, abduction, from the pubic insertion of the long adductor following along the mass of the muscle for 6 to 8 cm. The aponeurosis of the long adductor is cut just deep enough to see the muscle fibres. Careful finger dissection of the muscle sheath common to the three anterior adductor muscles leads directly to the lesser trochanter. Two forceps are inserted on either side of the lesser trochanter, exposing the lesser trochanter and the tendon of the iliopsoas muscle. Dissection of the iliopsoas muscle held aside (follow the tendon on its lateral aspect leading to the vessels). An angled spreader is positioned between the anterior aspect of the capsule and the medial border of the tendon, displacing the tendon laterally and exposing the capsule. Extra-articular exposure of the capsule with a rugine to displace the posterior medial circumflex pedicle. Longitudinal incision of the capsule continued along the inter-trochanteric line to the peri-acetabular region. The medial as well as the anterior aspect of the neck can be visualized by rotating the hip. The inferior and anterior portion of the head is visible: the iliopubic branch and the entire superior and medial wall of the acetabulum can be exposed.

Results: We performed 29 medial approaches. Nine for periprostheic pain, four for fresh fracture of the femoral head during posterior dislocation, four for old fractures of the femoral head during posterior dislocation, three for chondromatosis, three for tumours of the femoral head or the acetabulum, six for retractile periarthritis without arthroplasty. Hip arthroplasty (7) or not (6), median pain could be induced by the presence of retractile periarthritis with presence of synovial adherences to the femoral neck penetrating into the joint space; release relieved pain in 11/13.

Conclusion: The medial approach to the hip joint is a useful orthopaedic technique with a rapid learning curve.


Marc Soubeyrand César Vincent-Mansour Julie Guidon Alain Asselineau Gildas Ducharnes Charles Court Olivier Gagey Véronique Molina

Purpose of the study: High-energy varus or valgus ankle trauma causes severe injury to the capsule and ligaments. We describe a presentation associating massive tears of the lateral/medial collateral ligaments with a transversal wound of the corresponding malleolus. This wound results from excessive tension on the skin cause by the major varus/valgus. We have defined this injury as an open and severe ankle sprain (OSAS).

Material and method: This was a retrospective analysis. We search the databases of three participating centres using the corresponding diagnostic and therapeutic codes from January 2005 to January 2009. The identified files were screened to select patients with OSAS.

Results: There were 11 cases of OSAS. Eight involved the lateral side of the ankle and three the medial side. Mean age was 41 years (range 21–45). All patients were victims of a high-energy trauma (five motorcycle accidents) and four patients had fallen from a high point. Associated injuries were tendon section (n=3), section of the deep fibular nerve (n=2), and section of the anterior tibial artery (n=1). Pneumarthrosis was the only visible anomaly on the plain x-rays of seven ankles. Diagnosis was confirmed preoperatively in all cases clinically with varus-valgus stress manoeuvres.

Conclusion: OSAS is a rare misleading injury. Confusion with a common wound is possible. The risk is to miss acute instability and thus its treatment. The diagnosis should be proposed for all transversal wounds without contusion over the malleolus with normal x-rays.


Mouhamadou Habib Sy Abdou Razakh Ndiaye Jean-Claude Sané Amadou Ndiassé Kassé Babacar Thiam Boubacar Mbaye Mouhamed Tall Abdoulaye Bousso Daniel Handy

Purpose of the study: Bipolar dislocation of the first metatarsal, also called floating metatarsal, remains a rare traumatic injury of the first ray of the foot. This is an acute unstable post-traumatic metatarsophalangeal and cuneometatarsal injury occurring simultaneously or successively. Most earlier reports have been single case reports. We report here three successive cases in adults to study the mechanism of the injury, the clinical forms and the different therapeutic modalities.

Material and method: The patients were three males aged 35 years on average who presented a bipolar dislocation of the first metatarsal.

Results: The causal event was an automobile accident for two patients and a work accident for one. There was an open wound in two cases over the metatarsophalangeal joint. Orthopaedic metatarsophalangeal reduction was achieved in two cases and open cuneometarsal reduction in one. The cuneometatarsal reduction was maintained with a pin for six weeks. The auto-reduction was then continued.

Discussion: Described for the first time by English as a paired dislocation, in 1997 Liebner coined the term of a floating metatarsal. We were able to identify eight publications in the literature. The causal mechanism would be successive dislocation of themetatarsophalangeal joint first followed by the cuneometatarsal joint. The metatarsophalangeal dislocation was dorsal in two patients and lateral in one. The sesamoid girdle remained intact (Jahns 1) and in all cases followed the first phalanx in its displacement (Garcia Mata S+). The cuneometatarsal dislocation was dorsal in all cases. The skin opening involved the plantar surface in one case and was medial in the other, allowing externalisation of the first metatarsal head. The floating metatarsal was isolated in one case and associated with a fracture of the second metatarsal in two. Primary reduction of the metatarsophalangeal joint then the cuneometatarsal joint was achieved in all cases. Irreducibility due to a button effect was noted in one case. At minimum three months follow-up, there has been no evidence of deformity. The foot has remained pain free with correct shoe wearing. The control x-rays have not shown any subluxation.

Conclusion: The floating first metatarsal is an exceptional foot injury. Primary reduction of the metatarsophalangeal joint appears to be the rule. Adequate primary treatment ensures satisfactory outcome.


Jean-Christophe Bel Guillaume Herzberg

Purpose of the study: Because of the difficulty of maintaining anatomic reconstruction, plate fixation is limited for complex fractures of the calcaneum. Implants with angular stability can broaden classical indications and improve outcome.

Material and method: From February 2004 to February 2008 we treated 35 articular fractures of the calcaneum: 26 male, 6 female, 3 bilateral cases, mean age 41.46±15.99 years, age range 17–71, ≥ 3 displace fragments [Duparc IV:16; Duparc V: 16], preoperative CT [Sanders III: 22; IV: 13]. The surgical procedure was performed by one operator on days 4 to 7: lateral wide-L incision; articular and extra-articular reduction; lateral fixation using an AO-LCP® plate with locking screws. Intra- and postoperative X-rays (Boehler angle, talo- and cubocalcaneal congruence), postoperative CT. Rehabilitation: mobilisation of the talocalcaneal joint on day 21; partial weight bearing after 2 months; complete weight bearing after 3 months. Radiological and clinical (Kitaoka) follow-up every 60 months.

Results: Anatomic joint reduction was achieved and maintained by osteosynthesis (35/35). Late healing (smoking) (6/35). Healing: 2 months (21/35), 3 (14/35). Plate failure at 3 months without displacement (2/35). Anatomic joint reduction sustained ≥12 months (35/35). Gait without crutches after three months (35/35). Infection at 12 months (1/35). Mean follow-up (40 months, range 12–60).

Discussion: The purpose of surgical treatment is to achieve anatomic reconstruction of all joint surfaces and restore calcaneal height, length, width and alignment until bone healing. Complex joint fractures with a high risk of loss of correction or secondary nonunion have limited the use of conventional reduction-osteo-synthesis methods in favour of first-line reconstruction-arthrodesis. These complex fractures require plates with multiple fixations to maintain stability. Optimal recover of function can be achieved if the anatomic reduction of the joint surface and extra-articular elements can be maintained stable from the start and sustained to healing, demonstrating the usefulness of reconstruction. No series has reported this innovating therapeutic concept.

Conclusion: The reconstruction plate with locked screws enabled osteosynthesis of the most complex calcaneal joint fractures for which the discussion remains open concerning the role of osteosynthesis. The resistant fixation of all the fragments using screws with angular stability enabled stable reconstruction without loss of primary reduction, either secondarily or late, and allowed rapid rehabilitation. The long-term stability of the anatomic reconstruction guarantees good functional outcome which persists over time.


Julien Wegrzyn Vincent Pibarot Jean-Paul Carret Jacques Béjui-Hugues Olivier Guyen

Purpose of the study: In rheumatoid arthritis, 15 to 28% of patients present hip involvement, sometimes requiring arthroplasty. The purpose of this work was to evaluate the usefulness of cementless implants for patients with inflammatory hip disease, recognising that cemented implants are widely used for this indication.

Material and method: The was a retrospective series of 63 consecutive first-intention cementless total hip arthroplasties (THA) implanted from April 1986 to June 2007 in 48 patients (35 females), mean age 55 years (range 19–87), with rheumatoid arthritis. The majority of these patients were on a two-drug regimen of corticosteroids and methotrexate. Twelve patients were taking anti-TNF alpha. In all cases, both the femoral and acetabular elements of the implant were inserted without cement. The Postel-Merle-d’Aubligné (PMA) score was used for clinical assessment (preop, postop, last follow-up). Signs of loosening were noted on the plain x-rays.

Results: Mean follow-up was 103 months (range 12–264). There was a significant improvement in the PMA score. There were two intraoperative complications (calcar fissuration). Twenty-one cases (33%) exhibited acetabular protrusion requiring autologous bone graft. At last follow-up, all acetabular grafts were incorporated. At last follow-up there were no cases of deep infection. Three cases (4.8%) required uniplar acetabular revision for aseptic loosening at 127, 145, and 217 months after initial implantation. Major wear of the polyethylene insert was observed in all hips, associated with retroacetabular osteolysis. A new cementless implant was used for the revision in two cases, with satisfactory outcome a mean 41 months from revision. In addition, four cups and three stems presented unchanged lucent lines and had not been revised at last follow-up.

Discussion: THA is a therapeutic option for the rheumatoid hip. Long-term outcome with cemented THA has shown an increased incidence of deep infections and aseptic loosening in this context. At mean 9 years follow-up, we have had very encouraging results with cementless implants in this context.


Jean-François Lardanchet Eric Havet Patrice Manopoulos Joel Vernois Patrice Mertl

Purpose of the study: Theoretically, in first-intention total hip arthroplasty (THA), restoration of femoral offset (distance between the femoral axis and the joint centre) enables optimal function. The purpose of this study was to determine acceptable limits for variation in femoral offset without loss of function.

Material and method: We studied 122 hips (108 patients) who had THA with a straight cemented stem and a modular cone which could be adapted to enable three dimensional adjustment of the offset (more than 100 configurations). Mean patient age was 64 years. Most had primary or secondary degenerative disease (n=80) of the hip joint or osteonecrosis of the femoral head (n=21). The preoperative PMA score was 11.9 and the Harris score 49. Clinical and radiographic assessment was noted at mean 4.5 years follow-up. The radiographic femoral offset was measured semiautomatically in comparison with the healthy hip using the method described by Steinberg and Harris.

Results: At last follow-up, the mean PMA score was 16.4 and the mean Harris score 89. These clinically scores were statistically different depending on the degree of variation of the femoral offset. Outcome was better for offset increased 0 to 5 mm (PMA 17 and Harris 93). They were less satisfactory for decreased offset (PMA 15.9 and Harris 83) (p=0.01). They were also less satisfactory for an offset increased more than 8 mm, but non significantly.

Discussion: It has been established that increasing the femoral offset decreases the rate of dislocation, reduces the incidence of limping, the use of crutches, and increases the force of the gluteus medius, as well as range of motion and abduction. However, there is no known limit value.

Conclusion: It is advisable to increase the femoral offset during total hip arthroplasty; the increase should be to the order of 0 to 5 mm, and never be too great.


Frédéric Mouilhade Christian Mandereau Jean Matsoukis Philippe Oger Paul Michelin Franck Dujardin

Purpose of the study: The survival of a total hip arthroplasty (THA) depends mainly on the choice of the implant and the quality of the implantation. Mini-incisions have been criticised because of the increased risk of complications and the uncertainty concerning implant position. The main objective of this work was to assess this later feature.

Material and method: This was a prospective series of consecutive patients attending different centres from January 2008 to January 2009 comparing 100 THA implanted via the reduced Watson-Jones approach (2 centres) and 520 THA implanted in a third centre via the anterior hemimyotomy. Objective assessment (PMA, Harris) and early functional outcome (WOMAC, SF12), biological aggression (myoglobinaemia, CPK, blood loss), complications, and scanographic position of the implants were analysed.

Results: For the mini-Watson-Jones arthroplasties, there was a longer operative time (p< 0.0001), smaller scar, less consumption of analgesics the first postoperative day (p=0.003), and better objective and functional recovery at six weeks (PMA: p < 0.0001; Harris: p = 0.004; WOMAC: p < 0.0001; SF12: p = 0.007). Conversely, there was no significant difference for intraoperative or postoperative blood loss, intraoperative and early postoperative complications, elevation of serum muscle markers, or duration of hospital stay. Regarding implant position, significantly greater acetabular and cumulated anteversion was observed with the mini-incision (p=0.03 and p=0.002 respectively). Nevertheless, the proportion of well positioned implants (Lewinnek criteria) was not significantly different.

Discussion: This series confirms the contribution of the mini-incision to more rapid recovery. We did not find any difference in implant malposition related to approach. The first analyses did however show that the position of the implants is more reproducible with the conventional approach.


Christian Mandereau Frédéric Mouilhade Jean Matsoukis Philippe Oger Paul Michelin Franck Dujardin

Purpose of the study: The purpose of this study was to assess traumatic damage to muscles using biological markers. Two approaches were evaluated: a modified Hardinge approach (anterior hemimyotomy) and a reduced anterolateral approach (Rottinger).

Material and method: This was a multicentric prospective study conducted in three centres in 2008. The first 50 patients in each centre were included. Total creatinine phosphokinase (CPK) and serum myoglobulin levels were used to evaluate muscle damage. Blood samples were taken ten hours after surgery for myoglobulaeia and at one and two postoperative days for CPK. Student’s t test was used for the statistical analysis.

Results: There was no statistically significant difference in serum myoglobulin levels 10 hours postoperatively (p=0.25) or for CPK level at day 1 (p=0.098) and day 2 (p=0.105). Objective clinical recovery (Postel-Merle-d’Aubigné, Harris) and function (WOMAC and SF-12) were better at six weeks with the reduced anterolateral approach.

Discussion: These findings show that muscle aggression after mini-incision is to the same order as with the standard approach. The damage is however different: section for the Hardinge type approaches, stretching and contusion for the mini-incisions.

Conclusion: Use of biological markers specific for muscle tissue appears to be a simple way of quantifying muscle damage. However, adjunction of an imaging technique (MRI) might provide a more precise assessment of muscle injury.


François Bonnel Pierre Auteroche

Purpose of the study: Acetabular bone loss and loosening after total hip arthroplasty has been evaluated on plain x-rays (Vives, 1988; D’Antonio, 1989; Paprosky, 1994). Experience has proven that intraoperative assessment of bone loss is more important than previously thought. Our main objective was to quantify, intraoperatively, the real volume of bone loss. A secondary objective was to measure, independently of the observer, the course of acetabular loosening.

Material and method: This was a prospective series of acetabular loosenings (10 female, 4 male, mean age 68 years). Plain x-rays and computed tomography (CT) were obtained. A special image analysis software was used for the CT images after manual segmentation of the prosthetic acetabulum: automatic 3D volume and periprosthetic bone density were noted.

Results: Bone loss was divided into three stages. At stage 1, the volume lost was from 10 to 20 cm3; at stage 2, the volume loss was 20 to 40 cm3; and at stage 3 the loss was greater than 40 cm3. At six months, two hips exhibited early stage acetabular loosening with 5% lucency. The corresponding volumes between the stages observed on the plain x-rays and those measured on the CT scan did not correlate significantly.

Discussion: Compared with conventional x-ray methods for volume assessment, this computed tomography method is precise. The segmentation preparation was semi-automatic and took about 30 minutes. The prosthetic material did not hinder the image analysis. Results were produced automatically. The 3D representation enabled the operator to visualize intraopera-tively the acetabular zones the most affected, helpful for planning the procedure and choosing the implant. The density analysis gave the quality of the bone and the limit between healthy tissue, pathological tissue and the cement, increasing the volume of the bone loss.

Conclusion: These automatic measurement tools reduce analysis time. The precision of the measurements is a supplementary factor for determining the stage of the bone loss and the amount of graft tissue or bone substitute needed. This method can be used for all joints.


Bertrand Boyer Rémi Philippot

Purpose of the study: In 1975, Bousquet and Rambert invented the concept of dual mobility to reduce the risk of dislocation by changing the fixed insert on a Charnley implant to a mobile liner within a metal back shell held onto the femoral head by a retaining collar. This enabled implant recipients to maintain their intense activities without restriction after a first-intention procedure and to overcome muscle deficits after revisions. The screw-on PF stem was introduced in 1985. The purpose of our study was to demonstrate the long-term advantages and failures of this combination.

Material and method: This series included 240 hips with a PF stem and a Novae metal back cup. This was a retrospective analysis of a homogenous group of consecutive patients who underwent surgery from 1985 to 1990 (mean follow-up 22 years). Mean age at implantation was 56.7 years. This is the largest series, with the longest follow-up reported to date with dual mobile cups. The main indication was degenerative joint disease (79%) then osteonecrosis (11%). The implant was made of 316 L stainless steel. The PF was composed of the stem, a 22 mm diameter monobloc modular base and a 16 mm diameter neck. The tripodal Novae metal back cup was alumina coated. Preop, intraoperative and postop data were analysed. Clinical and radiographic follow-up (lucent lines, implant position) were noted at last follow-up. The Charnley, PMA, Devane and Sedel scores were noted.

Results: The preoperative PMA was 10.8, reaching 16.9 at last follow-up. The Devane score remained unchanged at 3. The mean Brooker score was 1.2. There were no cases with crural pain. Survival at last follow-up was 80%. There were no cases of dislocation, 18 intraprosthetic dislocations (4% at 9.25 years), four revisions of implant wear (1.7% at 19 years), five femoral revisions (2%), two infections (0.8%), nine patients lost to follow-up (4%) and 100 deaths.

Conclusion: The PF stem has a remarkable survival. The overall survival is comparable with series having an equivalent follow-up. The dislocation rate was zero, demonstrating the superiority of the dual mobility concept. There were several intraprosthetic displacements which came later than with Profil stems (role of the neck on the lip). The main complication was acetabular loosening, attributed to insufficient secondary fixation, improved later by adjunction of hydroxyapatite. Wear of the dual mobility cup should be modelised to define the role of osetolysis in these failures.


Jean-Marie Philippeau Ronny Lopes Denis Waast Norbert Passuti François Gouin

Purpose of the study: Follow-up of patients with a total hip arthroplasty with an Atlas® cup revealed unique acetabular osteolytic defects which remained asymptomatic for long periods. We thus conducted a systematic review.

Material and method: Our retrospective analysis included 217 Atlas® elastic impactable cups implanted consecutively from January 1993 to June 1995 and reviewed clinically and radiographically at mean 13.1 years.

Results: The incidence of acetabular osteolysis was 16%, the leading cause of replacements which occurred on average 8.8 years after the initial implantation. The overall actuarial cup survival was 76% at 13.5 years and 81% taking revision for periprosthetic osteolysis as the endpoint. Univariate analysis found a significant link between osteolysis defects and significant wear (p< 0.0001), Devane activity 4 or 5 (p=0.0005), low thickness polyethylene (p=0.006), and use of Zircone or alumina heads versus metal heads (diameter 22). There was no statistical link between the presence or not of a hydroxyapatite coating, despite a trend for less osteolysis with hydroxyapatite coating. At multivariate analysis, the only factors significantly linked with the presence of osteolysis were significant wear and thin polyethylene insert in the metal back.

Discussion: Mid-term follow-up appeared sufficient to assess the development of osteolysis considering the delays describe by others. The incidence of osteolysis, despite the high incidence and early appearance in our series, was very probably underestimated by the radiographic analysis. These results suggest we should search for defects systematically with this type of implant, especially if there is measurable wear. Although it is difficult to set a cut off, a polyethylene thickness less than 10mm should be avoided to limit the high risk of osteolysis defects. A more powerful statistical analysis and examination of explants is advisable in order to ascertain the reasons for this abnormally high level of failure by osteolysis at 13 years follow-up.

Conclusion: Systematic radiological and clinical review of all patients demonstrated an insufficient overall actuarial survival and an important rate of periprosthetic osteolysis. The association between periprosthetic osteolysis and polyethylene were was confirmed. Thin inserts appear to play an important role in this osteolysis via an abnormal wear and poor tolerance to wear debris from these implants.


François Molinier Jean-Louis Tricoire Jean-Michel Laffosse Hocine Bensafi Philippe Chiron Jean Puget

Purpose of the study: Correct implant position is one of the factors of long-term success of total hip arthroplasty (THA). Acetabular architectural defects caused by trauma can create difficult situations leading to potential complications and poor outcome. The purpose of this study was to examine retrospectively the results of THA implanted after fracture of the acetabulum treated surgically. The objective was to analyse the specific features and search for factors favouring poor outcome.

Material and method: The series included 43 patients who had a THA implanted after treatment of an acetabular fracture. Mean age at trauma was 44.5 years (range 16–87). Five patients had a THA immediately, mean age 75 years (63–87). Thirty eight patients had osteosynthesis. According to the Letournel classification, the fracture was elementary in 12 cases and complex in 26. In ten patients, there was residual joint incongruence measuring more than 2 mm after osteosynthesis. The hips evolved to degenerated joint (n=34) and or necrosis (n=10).

Results: Mean time from acetabular osteosynthesis to THA was 94.6 months (range 3–444), excluding those patients whose THA was implanted at the time of the osteosynthesis. Arthroplasty required removal of the osteosynthesis material (n=11), insertion of a supportive ring (n=14) associated with a bone graft (n=13). The acetabular implant was considered to be well positioned according to the Pierchon criteria in 16 hips and was lateralised (n=21) and/or ascended (n=17) in the other hips. Inclination was 42.8 on average, range 10–18. The five-year survival was 80%.

Discussion: Arthroplasty after surgical treatment of an acetabular fracture is a difficult procedure. Complementary procedures are often necessary complicating the surgery and increasing the risk of perioperative complications, particularly infection. It is difficult to position the acetabular implant, increasing the risk of postoperative instability and early loosening. This study demonstrated the difficulties of implanting a THA in this context where the revision rate is significantly higher than in first-intention THA.


Romain Bouchet Numa Mercier Dominique Saragaglia

Purpose of the study: The purpose of the study was compare dislocation rates of total hip arthroplasties (THA) implanted with a dual-mobility cup versus those implanted with a conventional cup.

Material and method: The first series (DM) included 105 patients who underwent first-intention THA implanted by one operator (DS) from January 2005 to June 2007. Dual mobility cups with a 28 mm head were implanted. There were 60 women and 45 men, mean age 76.6±5.65 years (range 53–93). Degenerative disease predominated (n=95, 90.%). The cups were Novae press-fit (SERF) (n=94), Stafit (Zimmer° 5N+5°? Avantage (Biomet) (n=5), and Gyros (Depuy) (n=1). The second series (S) included 108 patients who underwent the same procedure performed by the same operator (DS) from January 2003 to June 200 for the same indication. This series was the control series. There were 56 women and 52 men, mean age 74.19±5.9 years (range 53–87). Degenerative disease predominated (n=100, 92.6%). All implantations used metal-polyethylene bearing with a 28 mm head. The implants were St Nabor cups (Zimmer) (n=44), Cédior cups (Zimmer (n=41), and sealed cups (n=22). The same femoral stem with a 12–14 cone was used in both series. The reduced posterior approach was used in all cases without section of the pyramidal tendon. Inclusion required at least one year follow-up. Fischer’s test was used to compare dislocation rates. Other variables were analysed with the chi-square test.

Results: Regarding the dual-mobility cup series (DM) there were no cases of dislocation. In the conventional cup series (S) there were five early dislocations (< 3 months), giving a rate of 4.63%. although the dislocation rate was obviously higher in the S series, the difference was at the limit of significance (p=0.0597). In addition, the DM population was slightly older than the S series (p=0.0026).


Stefan Parent Sylvain Deschênes Guy Charron Gilles Beaudoin Hubert Labelle Marie-Claude Miron Josée Dubois

Purpose of the study: Recent studies have shown that the incidence of certain cancers would be due to ionising radiation received during diagnostic radiological explorations. It is thus important to optimise dosimetry. In this context, slot scanners have demonstrated potential for generating images with a quality comparable with conventional systems but with a considerable reduction in dose. We wanted to verify this proposition.

Material and method: Radiographs were obtained in 50 scoliosis patients (posteroanterior and lateral incidences) using the slot scanner (EOS, Biospace) and with a conventional machine (FCR-7501S, Fuji). A dosimeter was placed on the patient after each exam. Phantoms were used to adjust radiographic parameters for each system in order to obtain comparable quality images. Patient images were then acquired ad the dose calculated at several entry points. These measures were used to compare skin radiation and to initialise a Monte-Carlo simulation calculating the effective dose. Two orthopaedic surgeons and two radiologists then evaluated the visibility of the structures of interest using a standard check list. They read the images in random order and were blinded to all information concerning the patient and the system used to acquire the images. Visibility was noted on a non-parametric scale with 4 levels. Wilcoxon’s test was used to compare the visibility scores.

Results: Mean radiation of the skin in the thoracoab-dominal region varied from 0.11 to 0.30 mGy (effective dose 0.057 mSv) for the EOS and 0.73 to 2.47 mGy (effective dose 0.460 mSv) for the FCR-7501S. EOS provided significantly superior visibility for all structures (frontal view, p< 0.006), lateral view p< 0.04) except for the posterior arch of the lumbar vertebrae in the lateral view for which visibility was superior for FCR-7501S (p< 0.003).

Discussion: Using the slot scanner, the patients received 6 to 9 times less radiation to the skin for the thoracoab-dominal region and an 8-fold reduction in effective dose than with the conventional system. In addition, the doses presented in the literature for the same exam are much higher than reported for EOS.

Conclusion: The EOS slot scanner offers image quality which is globally superior to conventional systems while considerably reducing radiation dose.


Alexandre Nehme Ramy Chemaly Fouad Jabbour Nadim Moufarrej Georges El Khoury Ayman Hajjawi Norbert Telmont

Purpose of the study: Although the association between femoroacetabular impingement and degenerative hip disease has been well established, there is no way to detect a subgroup of hips with radiographic signs of impingement which will progress to degeneration. In addition, the majority of publications on the topic have been conducted in populations of patients with an overtly degenerative hip, where the incidence of signs of impingement is higher. There has not been any study searching for the presence of signs of impingement in a symptom free population. For this reason, we searched for signs of femoroacetabular impingement in a general population and attempted to find correlations with degenerative hip disease.

Material and method: We examined 200 computed tomography (CT) series of the pelvis performed for reason other than an orthopaedic indication. Four hundred hips were thus analysed with the Amira 4.1 3D software. We measured the classical coxometric parameters, orientation of the acetabulum, alpha angle, and presence or not of a bulge at the head-neck junction. Cartilage thickness was also mapped using a precise protocol. Cartilage thickness less than 0.25mm was considered for the purpose of this study to indicate degenerative disease. All data were processed with SPPS 17.0.

Results: There were 103 men and 97 women, mean age 58 years and 59 years respectively. The mean alpha angle was 55.7. Retroversion was noted in 20% of hips and 28% exhibited an anterior bulge at the head-neck junction. The mean cartilage thickness at the anterosuperior part of the hip was 37mm. Degenerative disease was present in 28 patients (14%) whose mean cartilage thickness at the anterosuperior portion of the joint was 21 mm. There was no significant correlation between cartilage thickness and acetabular orientation, alpha angle, presence of a bulge at the head-neck junction. Only age was significantly correlated with degenerative disease r=−0.158 [p< 0.0].

Discussion: Among the parameters currently considered to be risk factors for degenerative disease of the hip joint, age alone was statistically linked with reduced cartilage thickness in our symptom-free population. This would suggest that the essential mechanism underlying degenerative disease remains to be discovered.

Conclusion: Our findings suggest we should be prudent when proposing corrective surgery for femoroacetabular impingement. Such surgery should be reserved for symptomatic patients.


Ismat Ghanem Paul Yazbeck Ayman Assi Abyr Massaad Elie Romanos Khalil Kharrat

Purpose of the study: The cervical spine is the most mobile portion of the spinal column. Trauma raises a high risk of bone and ligament injury. Several cervical collars are used in adults with variable efficacy. For children the problem is the availability of adapted collars, although the issue has not been examined in the literature. The purpose of this work was to evaluate the efficacy of paediatric collars widely used for stabilising the cervical spine in children.

Material and method: Thirty asymptomatic patients aged 6 to 12 years participated in this study. Four types of paediatric cervical collars were used (Philadelphia, Miami Jr, Neloc, and the conventional stiff collar). The medium size, proposed for children aged 6 to 12 was used. A standard protocol was applied with the Vicon® system to analyse movement. Mobility of the neck was recorded with and without collars: flexion, extension, lateral inclination and axial rotation. The mobilities recorded without a collar were compared with the values obtained when the children wore each collar. The degree of mobility reduction was calculated for each collar. Seventeen children participated in a reproducibility study. ANOVA and Student’s t test were used for the statistical analysis.

Results: There was no statistically significant difference between the collars for efficacy in the saggital plane, though apparent stability was better with the Neloc. The degree of reduction was smaller with the Philadelphia than with the other collars in the frontal plane. Miami Jr and Neloc were more effective than the Philadelphia and the conventional collar in the axial plane.

Discussion: This study provide an assessment of the efficacy of paediatric collars to limit mobility of the cervical spine. Although a limited number of collars are proposed, those available on the market appear to ensure optimal stability, particularly the Miami Jr and the Neloc. The stabilisation problem, could be resolved by adapting the collars, particularly the height.


Hugues Nouaille-Degorce Jean-Michel Laffose Erik Estivalès Annick Sévely Pascal Swider Jérome Sales-de-Gauzy

Purpose of the study: There are limited data on the behaviour of intervetebral discs below arthrodesis for scoliosis. We have developed a reproducible MRI protocol for measuring the volume of the different components of the intervertebral disc and an original method for measuring disc hydration (ratio between the volume of the nucleus and the global volume). The discs studied were below fusions. The purpose of this study was to search for correlations between the disc volume and hydration and clinical outcome assess on standard x-rays.

Material and method: This was a prospective study conducted from 2005 to 2008. The series included 46 children with idiopathic scoliosis requiring arthrodesis (41 girls, 5 boys, mean age 15 years). The protocol included anteroposterior and lateral x-rays and MRI pre- and postoperatively and at 3 months and 1 year. 3D MRI reconstruction relied on a standard protocol validated in our research laboratory. These reconstructions produced a measurement of disc volume and its state of hydration. Two groups were identified using the plain x-rays: group A with what was considered to be a good result, well balanced spine and a horizontal disc subjacent to the arthrodesis; group B with what was considered a poor result with an unbalanced spine or oblique subjacent disc. Two groups were also defined as a function of postoperative reduction of the COBB angle. Group A’, reduction > 65% and group B’ reduction < 65%. Student’s t test was used for the statistical analysis.

Results: MRI series were obtained in 46 patients at 3 months and 28 at 1 year. At 3 months, there was an increase in nuclear volume (9.3%, p=0.056), global volume (5.2%, p=0.0017) and hydration (4.6%, p=0.056). At 1 year, the significant increases were, respectively, 15.4, 5.3 and 11.6%. At 3 months, there was a significant increase in disc volume in the groups A and A’. In group B, increase in disc volume (4.%, p=0.02) and hydration (13.9%, p=0.07) was only seen at 1 year.

Conclusion: This work enabled us to establish a significant correlation between increased disc volume and hydration as measured on the MRI and clinical outcome as assessed on the plain x-rays.


Nicolas Bonin Philippe Tanji Joffrey Cohn Frédéric Moyere Jean-Marcel Ferret David Dejour

Purpose of the study: The purpose of this work was to search for a relationship between the size of the femoral cam, the presence of cup retroversion, and the presence of labral or chondral lesions on the arthroscan in patients with an asymptomatic femoroacetabular impingement.

Material and method: Fifty arthroscans were obtained to explore impingements. The patients complained of groin or trochanteric pain limiting their physical activities. Generally signs of an anterosuperior impingement were demonstrated with flexion-adduction-internal rotation. The localization, dimensions and depth of the cartilage lesions were measured on the arthroscan. The sagittal slice was used to describe the acetabular chondral lesions anteriorly to posteriorly in clockwise manner. Presence of an associated labral lesion was noted. A second operator measured the hip joint anomalies causing the impingement: Notzli’s alpha angle was measured to search for a cam effect and the femoral offset was noted.

Results: The presence of a femoral cam or a decreased femoral offset were found in all cases. Mean alpha angle was 65°; mean offset was 0.09. Acetabular retroversion was identified in 24 patients (48%). Chondral lesions were a constant finding and were superficial (type 1& 2) in 32 patients (64%) and deep (type 3& 4) in 18 patients (36%). Labral lesions were found in 28 patients (56%). The depth of the chondral lesions, like the presence of a labral lesion, were correlated significantly with increased alpha angle and patient age. There was conversely no correlation with the presence of acetabular retroversion.

Discussion: This study confirmed the close relationship between femoroacetabular impingement by a cam effect and the severity of labral lesions and acetabular cartilage lesions. These lesions can favour degeneration, explaining the early centred or posterinferior damage observed in young patients with satisfactory acetabular cover.


Guillaume Riouallon Thierry Odent Vicken Topouchian Georges Finidori Jean-Paul Padovani Christophe Glorion

Purpose of the study: Data are scarce on the long-term outcome after anterior spinal fusion for idiopathic scoliosis in adolescents. The purpose of this study was to assess the clinical and radiological results obtained in a monocentric series using a single-phase fusion with pre-formed plates for the treatment of lumbar, thoracolum-bar and thoracic idiopathic scoliosis in adolescents.

Material and method: This procedure was performed in 111 patients from 1975 to 1993. Complete clinical and radiological evaluations were available for 35 patients, 7 male and 28 female. The SRS-30 questionnaire (translated into French by the authors) and the Oswestry score were used to assess functional outcome. Radiographic data were collected by an independent observer who read the pre-, post- and last follow-up images. Full spine images were available to assess correction of the curvature, frontal and sagittal balance, pelvic parameters, and degenerative changes in the subjacent discs. Functional outcome was assessed in relation to the radiographic findings.

Results: Mean follow-up was 22 years (range 16–31). Mean age at surgery was 14.5 years. At last follow-up, none of the patients were unemployed because of a spinal problem and 21 women had had one or more successful pregnancies. The mean SRS-30 score was 3.8/5 and correlated with the Oswestry score (13.8%). One patient underwent revision for disc herniation and one for posterolateral lumbosacral fusion because of persistent frontal imbalance. There as a fracture of the proximal screw in six patients with no sign of nonunion. At last follow-up, the mean Cobb angle was 14 (0–42). Frontal imbalance was noted in 18 patients, mean 12 mm. In the sagittal plane, three patients presented anterior imbalance. The pelvic parameters were within the range of the general population. Signs of L5-S1 disc degeneration were noted in ten patients, with no correlation with functional outcome.

Conclusion: Anterior fusion gives good long-term functional results in the treatment of idiopathic scoliosis in adolescents. Patients can pursue a normal occupational and familial life. This technique has provided satisfactory correction in the frontal and sagittal planes.


Jean-Luc Clément Edouard Chau Anne Geoffray Marie-José Vallade

Purpose of the study: The long-term results after surgical treatment of idiopathic scoliosis depends not only on the correction in the coronal plane but also the restoration of good sagittal balance and thus satisfactory sagittal curvatures. Recent publications have shown moderate correction of the thoracic hypokyphosis of idiopathic scoliosis with instrumentations using hooks and pedicular screws. We report results in the coronal and sagittal play with a reduction technique by simultaneous translation on two rods (ST2R).

Material and method: The radiographic parameters were measured preoperatively, at 6 weeks, at 1 year, and at last follow-up (range 2 – 7.4 years) in a consecutive series of 72 patients treated with posterior instrumentation and reduction using the ST2R system. The same operator performed all procedures using stable anchors (pedicle screws or self-stabilizing clamps). Screws and clamps had a threaded polyaxial extension which was linked to the rod by a connector. The deformity was reduced by progressively tightening the two rods alternatively using the nuts on the threaded extensions. This manoeuvre enabled the vertebrae to migrate progressively toward the rods, producing an anteroposterior translation.

Results: In the coronal plane, the mean main curvature was reduced from 54 to 17 and was maintained (70%) without loss of angle at last follow-up. There was not difference between the 56 patients with thoracic scoliosis (Lenke 1–4) and the 16 patients with thoracolumbar or lumbar scoliosis (Lenke 5 and 6). In the sagittal plane, for the patients with preoperative hypokyphosis (32 patients < 20), the mean kyphosis was significantly improved from 9 to 30 and remained stable at last follow-up (31) with a mean gain of 21 (p< 0.001). One patient still had hypokyphosis (18) at last follow-up. For patients with normal kyphosis preoperatively (> 20), the mean gain was 7.

Conclusion: In this consecutive series of 72 adolescents with idiopathic scoliosis, reduction by simultaneous translation on two rods was a simple and effect method which restored normal thoracic kyphosis.


Ibrahim Obeid Nicolas Aurouer Anouar Bourghli Olivier Hauger Olivier Gille Vincent Pointillart Jean-Marc Vital

Purpose of the study: Multisegmentary pedicle screws are becoming increasingly popular for idiopathic scoliosis in adolescents. For several years correction of the axial deformity has been achieved by vertebral rotation. Use of the EOS radiographic system and the sterEOS software enables a precise calculation of the vertebral rotation in the different plans while exposing the patient to reduced radiation doses. The purpose of this study was to determine the efficacy of the vertebral rotation technique for the correction of axial rotation of the apical vertebra (ARAV).

Material and method: This was a comparative prospective study. Two groups of ten patients underwent surgery for idiopathic scoliosis of the thoracic spine (Lenke 1 and 3). A posterior procedure was performed in all cases to achieve insertion of multiple level pedicle screws. In group 1, the correction was achieved by rotation of the rod and in group 2 by translation and veterbral rotation using the vertebral column manipulation (VCM) technique. Preoperative and 3-month postoperative EOS images were analysed by a radiologist and the spinal surgeon, both blinded to the operative technique. Two radiological parameters were analysed and compared. ARAV was calculated using the pelvic reference; any position error at image acquisition was thus automatically corrected.

Results: Mean age at surgery was 14 years (range 11–19); the two groups were not significantly different for epidemiological parameters, duration of hospital stay, type of curvature, preoperative radiological parameters, axial rotation of the apical vertebra preoperatively, and number of vertebrae instrumented or correction of the curvatures. The postoperative ARAV was significantly greater in group 1 (12.4 vs 4.3, p=0.0005) and the ARAV correction was significantly greater in group 2 (13.7 vs 4.5, p=1.9E-5). There were no early postoperative complications in either group.

Discussion: For posterior surgical correction of thoracic or double major idiopathic scoliosis, the VCM technique allows better correction of the ARAV compared with the rod rotation technique. Use of the EOS and the sterEOS software enabled a better evaluation and comprehension of the 3D correction while exposing the patients to a smaller radiation dose.


Moez Trigui Kamel Ayadi Baligh Elleuch Zoubeir Ellouze Lotfi Bahloul Wassim Zribi Mourad Aoui Fakher Gdoura Mohamed Zribi Hassib Keskes

Purpose of the study: Diastematomyelia is a rare spinal cord malformation defined as the presence of two separate spinal cords separated or not by an osseous, cartilaginous, or fibrous septum. Spinal malformations are almost always associated, raising difficult therapeutic challenges.

Material and method: We report three cases of congenital kyphoscoliosis associated with diastematomyelia in three girls aged 12, 14 and 15 years. The diastematomyelia was dorsal in one case, thoracolumbar in one and lumbar in the third. For all three patients, the indication for surgery was progression of the scoliosis with development of neurological signs of recent progressive aggravation. Preoperative distraction with a plaster cast was pursued for several months prior to posterior instrumentation. No attempt was made to correct the cord malformation nor achieve major correction of the spinal malformation. The instrumentation bridged the thoracolumbar scoliosis in one case and stopped above the malformation in the two others.

Results: The postoperative period was uneventful. There were no neurological complications. Preoperative neurological signs improved after surgery. Control radiographs showed an improvement in the deformity. At mean 6 years follow-up, these patients were not bothered in their everyday life. They had stable deformities which a globally balanced trunk. There were no signs of neurological evolution.

Discussion: The therapeutic strategy for diastematomyelia remains a subject of debate. For some authors, the spinal cord should be released systematically which for the majority, this is not necessary except if spinal distraction is planned or if there is a neurological problem. If there is an indication for spinal cord release, any spurs must be removed followed by the necessary dura mater plasty. In our three patients, and in agreement with the neurosurgery team, there was no need for neurosurgical release. The recent development of neurological deficits was explained by the important kyphosis rather by the intramedullary anomaly. Our therapeutic strategy thus focused on treatment of the scoliosis. This enabled us to stabilise the spine, protecting these patients from worsening neurological involvement and enabling good functional outcome. The zone of the malformation was not instrumented in all cases because the posterior arcs were deformed, but also to avoid compromising any future neurosurgical intervention.


Frank Fitoussi Amadou Diop Nathalie Maurel Brice Ilharreborde Ana Presedo Keyvan Mazda Georges François Pennecot

Purpose of the study: Clinical assessment of the upper limb in the cerebral palsy child remains difficult, and minimally reproducible. Thus many authors use for the upper limb, as for the lower limb, movement analysis to aid in decision making and obtain an objective measurement of postoperative results.

Material and method: Kinematic analysis and EMG were performed with the Vicon system in 27 cerebral palsy children with a spastic upper limb. The patients were compared with data obtained in a control population of 12 children. Eight patients had a second assessment after treatment. The experimental protocol followed the recommendations of the International Society of Biomechanics. The muscles targeted by the treatment were the pronator teres, the flexor carpi ulnaris, and the adductor pollicis (lengthening, transfer, toxin injection).

Results: Significant kinematic anomalies (p< 0.05) found were: excessive homolateral inclination and flexion/extension of the trunk, excessive abduction and external rotation of the arm/trunk, excessive elbow flexion, excessive pronation of the forearm, and flexion and ulnar inclination of the wrist. There was significant improvement postoperatively in the group of treated patients (p< 0.05) regarding the kinematics of the trunk, shoulder and elbow, as well as the EMG behaviour of the biceps/triceps couple despite the fact that the procedure had not affected these muscles or joints.

Discussion: Kinematic and EMG anomalies involving the trunk, shoulder and elbow represent motor strategies compensating for distal anomalies: – recruitment of the biceps allows improved supination, pulls the elbow in flexion. Since the patient cannot extend the elbow to achieve a task, compensation with the trunk increases the amplitude of the flexion-extension movement; – ‘extrinsic’ supination is achieved via an increase in external rotation of the arm in relation to the trunk and homolateral inclination of the trunk.

Conclusion: These observations have therapeutic implications: clinical, kinematic or EMG anomalies involving the trunk, shoulder, and elbow should not be treated per se but reevaluated after treatment of more distal anomalies.


Caroline Dana Stéphanie Pannier Stéphane Guéro Arielle Salon Zaga Péjin Christophe Glorion

Purpose of the study: Lengthening can be proposed for children with congenital or acquired short fingers in order to overcome the length defect and improve function, the aesthetic aspect, or enable installation of a hand prosthesis. Three techniques have been proposed. The purpose of this study was to compare the three techniques in terms of lengthening, achieved, cure index, and complication rate.

Material and method: The was a series of 13 lengthening procedures for metacarpals in children with congenital or post-trauma sequelae.

Results: The callotasis method was used for seven children. Slow distraction using a mini-external fixator was applied for progressive lengthening without bone graft. Mean lengthening was 13 mm (range 8–21) for mean a mean cure index of 81 d/cm (range 41.7 to 140.9). There was one major complication: fracture with angulation. The two-phase progressive distraction method with graft was used in four children. The distraction using a mini-external fixator was rapid, followed by second phase bone graft. Mean lengthening was 22 mm (range 13–32) with a cur index of 40.8 d/cm (range 32.8 to 46). There was one fracture of a grafted zone. Single-phase extemporaneous lengthening with immediate graft was used for two children. The intraoperative distraction of the osteotomy was followed immediately by insertion of the graft. Mean lengthening was 9 mm for a cure index of 50 d/cm. One patient required tenolysis of the extensor at six months because of adherences at the graft site.

Discussion: Our results suggest that the two- phase distraction-graft method enables greater lengthening than the callatasis technique for shorter treatment periods but a the cost of a second operation and donor site morbidity. The extemporaneous lengthening method is less ambitious, achieving lengthening to the order of 10 mm, but with a less aggressive procedure.


Eric Maurice Eric Maurice Stéphane Barbary François Dap Gilles Dautel

Purpose of the study: Amputation of the thumb is a serious hand injury producing a major functional and aesthetic handicap. In 1980, Foucher proposed a twisted two toes transfer associating elements harvested from the first and second toes on the same pedicle for the reconstruction of an ‘articulated’ thumb with preserved potential for growth.

Material and method: Since 2002, two children aged 10 and 14 years underwent this procedure. The thumb amputation was trans MP for one and at the base of P1 for the second. The transfer associated a sheath of skin from the hallux to wrap around the skeleton of the second toe which was harvested as need to the IP or the MP. The aesthetic, functional (400 point scale), and radiological outcomes were assessed.

Results: Follow-up was 5 years and 2.5 years. The aesthetic result was comparable to wrap-around transfers. Regarding the functional outcome, the overall hand function was scored 86% and 72% of normal, mobility 77% and 72%, and force 75% and 79%. One patient had persistent deficient active flexion of the interphalangeal joint because of flexor adherences. Despite the reconstruction of the “two-joint” thumb, fine movements were difficult. Sensitivity was noted normal: Weber 5 and 8 mm. Healing of the donor site was rapid and the sequelae discrete. The first ray was preserved. Gait was not hindered. In one patient, radiographs showed skeleton growth.

Discussion: Transfer of the second toe provides a potential for growth, but the aspect is less than satisfactory and the functional results often disappointing. There are no indications except for very proximal amputations. Total transfer of the great toe would also provide potential for growth, but the voluminous aspect and the very important sequelae for the foot rule out this option.

Conclusion: For growing children, the twisted two toe transfer for amputations of the metacarpophalangeal region is the only available technique allowing nearly normal reconstruction of the thumb in terms of mobility, force, sensitivity, appearance, and growth. The foot reconstruction is simple, aesthetic and functional. The complexity of the procedure may nevertheless limit is use.


Eric Maurice Daniel Molé Gilles Dautel

Purpose of the study: A stiff shoulder in internal rotation is a classical complication of obstetrical injury to the brachial plexus. The condition generally associates glenohumeral dysplasia. In 2003, Pearl proposed arthroscopic release of the shoulder, with or without latissimus dorsi transfer as an alternative to an open procedure. We report a series of 13 patients who underwent this procedure.

Material and method: From 2004 to 2007, 13 children aged 1 to 11 years (range 3.5) underwent surgery. The procedure was an arthroscopic tenotomy of the intra-articular portion of the subscapularis associated with release of the anterior capsuloligament structures without tendon transfer. A thoracobrachial resin cast maintained the shoulder in maximal external rotation for six weeks. The functional outcome was assessed on the basis of the passive and active range of motion and the Mallet score. Pre and postoperative MRI was used to assess glenohumeral dysplasia and check its correction.

Results: Mean follow-up was 23 months (range 5–40). There were no complications. Mean immediate postoperative gain was 53 (range 30–70) for external rotation (RE1). On average, passive RE1 improved from −5.4 to +57.7. Eight patients (61%) recovered active external rotation (57.5 on average). Mean active abduction improved from 45.8 to 56.5. Active internal rotation declined in 38% of the shoulders. The Mallet score improved in 69% of the shoulders. The best results were observed for children aged less than 4 years. There was one failure, related to major dyplasia which could not be reduced with an open procedure. Correction of the glenohumeral dysplasia was noted on 7 of the 9 MRI performed and the retroversion angle of the glenoid improved from −28.2 to −25.6, on average.

Discussion: Open techniques are aggressive and only variably effective. A majority of our patients (8/13) achieved improved passive and active RE1 solely with the arthroscopic procedure. Correction of the glenohumeral dysplasia with growth appears to correspond to the clinical improvement but further follow-up is needed.

Conclusion: Our results are comparable with those reported by Pearl. This is a minimally invasive easy-to-perform technique. For children aged less than 4 years, systematic tendon transfer does not appear to be necessary.


Abdelaziz Abid Jérome Sales de Gauzy Gorka Knorr Frank Accadbled Philippe Darodes Jean-Philippe Cahuzac

Purpose of the study: Duplication of the thumb is the most common congenital anomaly of the first ray. The characteristic feature of type IV is the diversity of the clinical forms and the presence of certain complex forms particularly difficult to treat (Hung IVD). We propose a new procedure for reconstruction of IVD type thumb duplication.

Material and method: This new procedure was used for thumb reconstruction in two boys with type IVD thumb duplication. Mean age at surgery was 10 months. Surgical technique. The future incisions were traced with a central skin resection removing the most hypoplastic nail entirely (generally the radial nail). At the bone level, a longitudinal osteotomy of the proximal phalanges was made over the entire length to remove the central part and obtain a width for the first phalanx comparable to that of the contralateral thumb. An oblique osteotomy was cut in the base of the distal phalanx of the ulnar hemithumb with resection of a radial corner. The same type of osteotomy was performed at the base of the distal phalanx of the radial hemithumb, but with preservation of the radial corner and resection of the rest of the radial thumb. The proximal hemiphalanges were sutured as were the bases of the distal phalanges. This produced automatic realignment and stabilisation of the interphalangeal joint without an ungueal intervention.

Results: The three children were reviewed at 24, 18 and 12 months. The Horii score was good in all cases.

Discussion: Type IVD duplications of the thumb are difficult to treat and may leave serious sequelae. Our technique is based on the principle of a central resection of the proximal phalanges associated with partial resection of the base of the distal phalanges. This enables realignment and stabilisation of the interphalangeal joint while avoiding the problem of ungueal dystrophy since only one nail is preserved. Our preliminary results are encouraging but must be confirmed with a longer term study.


Julien Wegrzyn Julien Chouteau Rémi Philippot Michel-Henri Fessy Bernard Moyen

Purpose of the study: Revision ligamentoplasty can improve function and laxity control but with a less satisfactory result than obtained after primary reconstruction. The purpose of this study was to report management practices and results of revision ACL reconstructions and to assess the course of meniscocartilage damage and determine causes of failures.

Material and method: This was a consecutive series of ten patients, mean age 30 years (range 17–48) who underwent arthroscopic reconstruction. The review was retrospective. Criteria for failure were redevelopment of instability and/or pain, objective laxity, and a KT-100 differential greater than 5 mm. The IKDC protocol was used for the clinical and radiographic assessment. Goniometry, arthroscan and MRI were also performed. The position of the tunnels was analysed according to the Aglietti criteria. The type of surgery, transplant used and status of the menisci and cartilage were analysed.

Results: Mean follow-up of the second revision was 38 months. At last follow-up, seven patients had a global IKDC score of A or B. Two patients had resumed regular sports activities at the same level as before the first tear, four at a lower level. Four had interrupted their sports activities. At the second revision, two patients exhibited medial femorotibial narrowing measured at less than 50%, three had a remodelled medial femorotibial compartment and one a remodelled lateral compartment. All had a partial homolateral meniscectomy and seven had cartilage injuries (3 ICRS III and 1 ICRS IV). At the successive interventions, the number of meniscal lesions, meniscetomies, and cartilage lesions increased (p=0.016, 00098 and 0.0197 respectively). ICRS grade II and IV cartilage lesions were associated with an overall C or D IKCD (p=0.0472). The cartilage lesions were more frequent in knees with meniscal lesions and meniscectomies. The causes of failure of the primary ligamentoplasty and of the first revision (six and seven patients respectively) were poor position of the tunnels (respectively 4 and 1 patients).

Discussion: In 70% of the patients outcome after repeated revision was good or excellent, although the quality declined with increasing number of revisions, in relation to the development of meniscal and cartilaginous lesions. These latter were more frequent and more severe, related to recurrent laxity. Failures were mainly due to recurrent trauma followed by technical errors.


Kheriddine Zehi Arafet Boundka Naoufel Tlil Yahya Jeridi Mounir Zouari

Purpose of the study: The tibial slope is an important parameter for knee surgery. Tibial slope designates the inclination of the tibial plateaus in the sagittal plane. The presence of a tibial slope and its value is intimately related to the condylotrochleal profile. The importance of tibial slope in knee disease and knee surgery is now universally recognised.

Material and method: We reviewed 140 cases of anterior cruciate ligament (ACL) ligamentoplasty performed at the institute; 25 failures were identified. After analysis of the position of the tunnels, particularly the femoral tunnels, the most documented cause of failure, as well as other factors of failure, we measured the mean tibial slope in all operated patients.

Results: Subjective Lachmann and the IKDC and ARPEGE scores associated with the dynamic study (TELOS) helped understand why knees can become unstable despite good surgical technique.

Discussion: William and Lissner established a mathematical relations between tibial slope and stress forces applied to the ACL. Dejour and Bonnin demonstrated the effect of the tibial slope on anterior subluxation and single leg stance. The tibial slope should thus be considered for all knee procedures. Bonnin demonstrated that an excessive slope can be a factor of plasty failure.


Nicolas Lefévre Serge Herman

Purpose of the study: The double-bundle technique for the reconstruction of the anterior cruciate ligament (ACL) enables anatomic repair. This reconstruction may not however be possible in all patients due to the variable quality of the graft material: insufficient length and diameter. For the double-strand hamstring technique, the diameter of the posterolateral bundle (PL) can be less than 6 mm, and for the anteromedial bundle (AM) sometimes less than 7 mm. With the bundle-strand TLS larger sized grafts can be constructed in all cases.

Material and method: We operated 15 patients with full thickness tears of the ACL. The standard TLS method was used for each strand. The semitendinous and the gracilis tendons were shaped in a closed loop into short four-strand grafts measuring 45 to 50 mm. The four tunnels were reamed retrogradely arthroscopically. The graft was fixed with mersilene tape in the tunnels and locked with four titanium screws with the knee in extension for PL and 45° for AM. The diameter of each bundle was measured. Outcome was compared with that of 15 patients treated with the double-bundle technique using hamstring tendons fixed with a femoral endobutton and a tibial screw.

Results: There were no pre- or postoperative complications in the two groups. The mean diameter of the PL bundle was 6.2 mm for the endobutton group and 7.9 mm for the TLS group (p< 0.001). The diameter of each bundle with the TLS technique was thus significantly greater in the femoral notch with no deficit in postoperative extension.

Conclusion: The TLS method has already demonstrated excellent results for the single-bundle reconstruction of the ACL. The TLS double-bundle reconstruction technique provides a quality bundle with a large diameter in all patients, irrespective of the hamstring quality. The long-term results should confirm the efficacy of this double-bundle technique.


Khéireddine Zéhi Mohamed Bettoumi Arafet Boundka Hedi Rbai Yahya Jeridi Faycal Saadaoui Mounir Zouari

Purpose of the study: This work examined the clinical, radiological, and videoarthroscopic features of partial tears of the anterior cruciate ligament (ACL) and analysed results of ligament plasties.

Material and method: Mean age was 32 years. Patients complained of instability accidents in 70% of cases. The Lachman test was noted soft endpoint to + or ++ in 90%. A palpable click was found in 60% but was considered severe in two cases only. Telos laxity was moderate (about 5 mm) in 80%. Mean time to surgery was relatively short (9 months). Arthroscopic exploration revealed rupture of the anteromedial head of the ACL with preservation of the posterolateral component. There was a meniscal injury in nine knees. Early in our experience we performed a total plasty for nine patients (six using hamstring tendons and three with the patellar tendon). At the present time, we spare the posterolateral head and make a partial plasty of the anteromedial head (11 knees: 3 harvesting a single tendon [gracilis] and eight using the gracilis and the semitendious) associated with lateral reinforcement in five.

Results: Mean follow-up was 30 months; 30% of patients had knee pain. Three knees exhibited a soft endpoint (+) all after a total plasty. There were no cases of quadriceps motion deficit or amyotrophy.

Discussion: The existence of partial tears of the ACL were confirmed in this series. This type of tear corresponds to an objective condition seen arthroscopically and also to precise clinical presentations and biological findings: minor signs of instability with moderate objective anterior instability to the order of 5 mm.

Conclusion: Considering this work and a review of the literature, the diagnosis of partial tears of the ACL could be established from the physical examination and measurements of anterior knee laxity. Reconstruction of a single head provides better results than complete reconstruction which would sacrifice an intact portion of the ACL.


François Luthi Julien Favre Kamiar Aminian Olivier Siegrist Brigitte Jolles

Purpose of the study: Reconstruction of the anterior cruciate ligament (ACL) controls laxity but does not enable restoration of strictly normal 3D kinematics. The purpose of this study was to compare the kinematics of the pathological knee with that of the healthy knee after ACL plasty. This study applied a new ambulatory system using miniature captors.

Material and method: Five patients with an isolated injury of the ACL participated in this study. The patients were assessed after injury (T1), at five months (T2), and at 14 months (T3) after surgery. The assessment included laxity (KT-1000), the IKDC score and the Lysholm score. The 3D angles of the knees were measured when walking 30 m on flat ground using a system composed of to small inertia units (3D accelerometer and 3D gyroscope) and a portable recorder. Functional settings were optimised and validating to ensure easy precise measurement of the 3D angles. Symmetry of the two knees was quantified using a symmetry index (SI) (difference in amplitude normalised in relation to mean amplitude) and the correlation coefficient CC.

Results: Clinical indicators improved during the follow-up (IKDC T1: 3C, 2C; T2: 5B; T3: 2A, 3B; subjective IKD: 53–95; Lysholm 67–96). Mean laxity improved from 8.6m to 2.5 mm. The gait analysis showed increased symmetry in terms of amplitude for flexion-extension (SI: −17% at T1, −1% at T2, 1% at T3), and an increase in symmetry in terms of the rotation signature (CC: 0.16 at T1, 0.99 at T2, 0.99 at T3). There was no trend to varus-valgus.

Discussion: This study demonstrates the clinical application of the new ambulatory system for measuring 3D angles of the knee joint. Joint symmetry increased after ACL plasty but still showed some perturbation at 14 months. The results observed here are in agreement with the literature. Other patients and other types of gait are being analysed.

Conclusion: This portable system allows gait analysis outside the laboratory, before and after ACL injury. It is very useful for follow-up after surgery.


Adrian Ioncu Frank Ly Thaï Bach David Dejour

Purpose of the study: The form of the anterior tibial tuberosity (ATT) has not been described in anatomy studies. Insertion of the patellar tendon can, by its form, modify the lever arm of the extensor system and induce pathological conditions having an impact on the form of the apex or tip of the patella. The purpose of this work was to analyse the types of tibial tuberosities observed on the radiographs of 50 patients.

Material and method: Fifty patients were included in this prospective study. The form of the ATT was defined by two angles. These angles were measured on the strictly lateral x-ray. The ATT-shaft angle (ATT-d) was defined by the intersection between the anatomic axis of the tibial diaphysis and the anterior cortical of the ATT which corresponds to the insertion of the patellar tendon. The ATT-metaphysis angle (ATT-M) was defined by the angle between the tangents of the anterior metaphyseal cortical and the anterior cortical of the ATT. The height of the patella was also measured as described by Caton and Deschamps. The form of the patella on the lateral was described according to the Grelsamer criteria, and its form on the 30° axial view according to the Wiberg classification. The presence of trochelar dyplasia was determined using the Dejour method. The statistical analysis accepted p < 0.05 as significant. The coefficients of correlation R were calculated with a ½ log covariance matrix [1+R]/[1−R].

Results: The form of the ATT was given by the minimal value between the ATT-D and the ATT-M. This angle measurement revealed major variation. Three types of ATT were defined: type I 0≤ATT-M≤15 and ATT-D≤5, type II 15 < ATT-M < 20 and 5 < ATT-D < 10 and type III 20≤ATT-M 10≤ATT-D. There was an obvious correlation with the form of the patellar apex. The type III form of the patella was always associated with a type I ATT; there was a significantly association between patella type I and ATT type II and patella type III and ATT type I. There was no correlation with the height of the patella or with the form of the trochlea or the patella.

Conclusion: The form of the ATT is quantifiable and becomes a parameter to consider in the analysis of patellofemoral osteoarthritis.


Christophe Hulet Bertrand Galaud Elvire Servien Ramiro Vargas Philippe Beaufils Florent Lespagnol Anthony Wajsfiz Olivier Charrois Jacques Menetrey Pierre Chambat Christophe Javois Patrick Djian Romain Seil

Purpose of the study: The purpose of this retrospective multicentric analysis was to study the functional and radiological outcomes at more than 20 years of 89 arthroscopic lateral menisectomy procedures performed on stable knees.

Materialandmethod:The series included 89 arthroscopic lateral meniscectomies performed on knee with intact anterior cruciate ligaments (ACL). Mean follow-up was 22±3 years; 56 male, mean BMI 25±4, mean age at meniscectomy 35 years, mean age at last follow-up 57 years. Most of the injuries were vertical (41%), complex (22%) and radial (20%) lesions. The middle segment was involved in 79%. The meniscectomy removed more than one-third of the meniscus in 67%. All patients were reviewed by an independent operator for subjective assessment KOOS (100% normal) and IKDC, and for objective clinical and radiological measurements (IKDC). P< 0.05 was considered statistically significant. There was no independent control group.

Results: Revisions were performed for 16% of the knees. Intense or moderate activity was maintained by all patients. The subjective IKDC score was 71.1±23, comparable with an age and gender matched population. The mean KOOS score was 82% for pain, 80% for symptoms, 85% for daily activities, 64% for sports, and 69% for quality of life. The rate of of osteoarthritis was 56%, and 44% of patients had a difference between the two knees for osteoarthritis. The incidence of osteoarthritis was 53% and shift to valgus on the arthritic side was significantly associated with osteoarthritis, while the opposite side was well aligned. The knee was pain free in 27% of patients. Significant factors for good prognosis were age less than 38 years at first operation, moderate BMI, and minimal cartilage damage (grade 0 or 1).

Conclusion: After the first postoperative year after arthroscopic lateral meniscectomy on a stable knee, the results remain stable and satisfactory for more than 22 years. Nevertheless, patients aged over 40 with a high BMI and cartilage damage at the time of the first operation have a less encouraging prognosis.


Bruno Chemama Nicolas Pujol Julien Amzallag Philippe Boisrenoult Philippe Oger Philippe Beaufils

Purpose of the study: Tibial osteotomy to correct for varus deformity is a well defined procedure. Survival has reached 80% at ten years. Nevertheless, a number of early failures are related to inadequate initial correction. Computer assisted surgery has demonstrated its efficacy for knee arthroplasty. We hypothesised that it could also improve the reliability of correction for tibial osteotomy.

Material and method: From 2007, in a prospective case-control study, 34 tibial wedge osteotomies were performed, 17 were computer assisted (Navitrack, Orthosoft) with plate fixation (Tomofix, Synthès) without wedge insertion; the objective was valgus measuring 2 to 5°.

Results: The two series were comparable for age (54.2±6 and 55.7±4.5), body mass index (28.9±6.2 and 28.7±5.7), and varus deformity (7.2±3 and 6.2±6) respectively in the standard and navigated groups. Osteoarthritis was more severe in the navigated group, with five patients stage 2 and 12 stage 2 versus one stage 1, 12 stage 2 and 4 stage 3 in the standard group (p=0.0152). The duration of the operation was not longer in the navigation group (p)0.2779). Comparisons were made for alignment at three months, between the groups and in relation to the preoperative data. There was no significant difference between the intraoperative navigation alignment and the alignment measured at 3 months: 3.6±6 and 2.5±3 at 3 months (p=0.2187). At 3 months, there was no significant difference in alignment between the two groups with 3.22 and 2.5±1.6 valgus in the standard and navigation groups respectively (p=0.2136). The objective was achieved in 25 patients: 12 in the standard group and 13 in the navigated group. In the navigation group, there were four failures, no cases of over correction, two cases of insufficient valgus at 1.5, one neutral alignment, and one recurrent varus. In the standard group, there were five failures with two over corrections at 7 and 8, two under corrections at 0 and 1, and 1 recurrent varus at 4.

Discussion: We were unable to prove that navigation improves the reliability of the correction but it did appear to avoid important errors, particularly over correction. Few series have compared standard varus navigated osteotomies, and all published series have been small. Our study has the advantage of being monocentric with two comparable series of patients. The sample size nevertheless remains small and the follow-up short.


Jean-Marie Fayard Elvire Servien Sébastien Lustig Philippe Neyret

Purpose of the study: Transposition of the anterior tibial tuberosisty (ATT) is often performed during the treatment of periodic dislocation of the patella. The purpose of this retrospective study was to evaluate the rate of medial femorotibial osteoarthritis and medial patellofemoral osteoarthritis after ATT transfer.

Material and method: We reviewed 129 knees in 106 patients who underwent surgery from 1988 to 2004. The patients were reviewed at mean 9 years follow-up, minimum 2 years. Three groups were defined:

isolated descent (n=15),

isolated medial shift (n=19), and

descent and medial shift (n=95).

The degree of the medial shift and the descent depended on the distance from the tibial tuberosity to the trochlear notch and the Caton-Deschamps index measured preoperatively. Patients who underwent surgery for chronic anterior laxity and/or meniscal lesions were excluded (n=3). All patients were free of osteoarthritis before surgery. A complete radiographic series was available for 102 knees. Unilateral periodic dislocation of the patella was present in 60 patients whose knee x-rays were obtained bilaterally.

Results: All patients in group 2 were free of osteoarthritis. In group 2, the rate of medial femorotibial osteoarthritis was 10.5%; the rate of medial patellofemoral osteoarthritis was 21%. In group 3, the rate of medial femorotibial osteoarthritis was 7% and that of medial patellofemoral osteoarthritis 14%. For patients with unilateral periodic patellar dislocation, only the operated knees exhibited medial patellofemoral osteoarthritis (12%). The rate of medial patellofemoral osteoarthritis was significantly greater for knees with a medial shift of the ATT. The rate of medial femorotibial osteoarthritis was 6.8% for knees with medial shift versus 8.3% for the index knees. There was no significant difference between the medial shift knees and the index knees for medial femorotibial osteoarthritis.

Discussion: Biomechanical studies have shown increased stress forces on the medial compartment after medial shift of the ATT. However, these studies were performed with normal knees free of the morphological anomalies generally present in knees exhibiting periodic patellar dislocation (abnormally high tibial tuberosity femoral notch distance, trochlear dysplasia. In our series, regarding the rate of medial femorotibial osteoarthritis, there was no significant difference between the knees which underwent a medial shift of the ATT and healthy knees. Consequently, medial shift of the ATT should be avoided when unnecessary; the morphology of the trochlea (depth, morphology of the medial component) can induce increased medial stress on the patellofemoral joint.


Frédéric Châtain Renaud Barthélémy Olivier Tayot Hervé Chavane Jean-Luc Delalande Olivier Guyen Thierry Gaillard Stéphane Denjean Vincent Pibarot Jacques Béjui-Hugues Jean-Paul Carret

Purpose of the study: Data are scarce in the literature on lower limb length discrepancy (LLD) after total hip arthroplasty (THA). This parameter is difficult to evaluated intraoperatively with conventional instruments. In addition LLD after THA is often poorly tolerated and can be a source of legal suites. The purpose of this work was to evaluate the contribution of navigation for controlling lower limb length during implantation of a THA.

Material and method: Sixty-five THA were implanted in 63 patients, aged 35–81 years, using a passive navigation system based on a function reference system which controlled the position of the implants and the length of the operated leg. Limb length and femur length were measured radiographically on both sides before and after surgery. The horizontality of the acetabular U lines was measured on the AP view of the pelvis. An independent radiologist made all measurements.

Results: The precision of the radiographic measurements was < 3 mm. The precision of the navigation system was < 3 mm. Subjectively, 56 of the 63 patients did not have a feeling of LLD preoperatively. No un programmed difference > 3 mm in leg length between the before and after THA measurements was noted. Preoperatively, seven patients complained of lower back pain related to LLD and three had a compensated shoe measuring 5 to 10 mm. These latter three patients had a horizontal pelvis (< 1) after THA. In all cases, the overall length correction was achieved by adapting the length of the neck.

Discussion: In our opinion, not all radiologically determined and/or clinically perceived LLD should be corrected. Care must be taken to ensure that permanent preoperative hip flexion does not perturb limb length measurements.

Conclusion: The navigation system used in this series for the implantation of THA was able to control operated limb length with precision.


Didier Mainard Stéphanie Valentin Jérome Diligent Élie Choufani Marie Leyder Nicolas Berte Laurent Galois

Purpose of the study: The right position of total hip arthroplasty (THA) implants affects short-, mid- and long-term outcome and complications. Navigation can improve implant position relative to a reference plane, in particular during mini-invasive implantation. The purpose of this work was to compare the position of the prosthetic cup in two series, one implanted with a navigation system and one with the conventional technique.

Material and method: The same surgeon performed the operations in each group of 42 patients (matched for age, gender, BMI, side). In the historic non-navigated series, a press fit femoral implant was used (Excia). The cups were either press fit (Ovalock or Plasmacup), or cemented with polyethylene inserts. The Hardigne incision (15 cm) was used for the conventional implantations. In the prospective navigated series, a press fit femoral element (Excia) and a press fit cup (Plasmacup) were implanted. The Orhtopilot navigation system was used (reference plane: Lewinnek anterior pelvic plane). The adapted Hardinge incision (5 cm) was used for the mini-invasive implantations. Inclination was measured on the weight-bearing pelvis relative to the radiological U line; the Pradhan method was used for anteversion. The objective was to achieve 45° horizontal inclination and 15° anteversion.

Results: In the non-navigated series, the inclination was 53±8 and in the navigated series 44±5.6. On average, inclination decreased significantly (8). Anteversion in the non-navigated series was 7±4, and 12±5.3 in the navigated series. On average, anteversion increased by 6 (statistically significant). The number of cups in the Lewinnek safety zone was 21 of 42 (50%) in the non-navigated series and 38 of 42 (90%) in the navigated series (statistically significant). The increase in leg length was 6.2 mm in the non-navigated group and 4.4 in the navigated group.

Discussion: Positioning did not take into account the preoperative analysis of the hip, but could adapt to scanner or EOS data. Navigation should also integrate offset, femoral position, and leg length.

Conclusion: Navigation of the prosthetic cup improves precision positioning in relation to the reference objectives, in particular, for mini-invasive surgery.


Jean-Yves Jenny Nicolas Robial Cyril Boéri

Purpose of the study: Leg length discrepancy (LLD) can be a common reason for patient dissatisfaction after implantation of a total hip arthroplasty (THA). The failure rate is non negligible for conventional implantation techniques. Navigation systems might be able to improve precision.

Material and method: We used an imageless navigation system (Orthopilot™, Aesculap, FRG) for routine first-intention THA. LLD was determined on the AP view of the pelvis in the upright position to determine the desired correction. Captors were screwed onto the homolateral iliac crest and femur. The system analysed their respective positions at the beginning of the procedure thus defining the reference length. During implantation, the size and the height of the femoral implant and the length of the prosthetic neck were programmed virtually by the navigation system in order to obtain the desired correction which was then reproduced on the definitive implants. At the end of the operation, the final length of the limb was measured the same way as initially. The result of the correction was measured on the AP view of the pelvis in the upright position under the same conditions as initially. We compared 30 navigated THA with 30 THA implanted with the conventional technique. We analysed the residual length discrepancy and the percentage of the cases where the desired correction was achieved. Student’s t test and the chi-square test were used for the statistical analysis taking p< 0.05 as significant.

Results: Residual length discrepancy was 5 mm for the navigated THA and 9 mm for the conventional THA. The mean difference between the desired correction and the final correction was 2 mm for the navigated THA and 6 mm for the conventional THA. The desired length was obtained in 26 hips with navigated THA and in 17 with conventional THA. Residual LLD > 10mm was observed in 2 navigated THA and 9 conventional THA. All differences were significant.

Discussion: The navigation system used in this study enabled improved quality correction of lower limb length after implantation of a THA. Patient satisfaction should be globally improved.


Benjamin Guenoun Frédéric Zadegan Florence Aim Didier Hannouche Rémy Nizard

Purpose of the study: Leg length discrepancy after THA is a common complication and source of recurrent complaints from patients. To date, no reliable and reproducible technique has come forward to enable accurate quantification of all radiological parameters of the lower limb. Nevertheless, preoperative planning for hip arthroplasty requires knowledge of many limb parameters, in particularly leg length discrepancy, femoral offset, or the head-neck angle. The most widely used method is to use the 2D radiographs. The EOS system uses two digitalised 2D images taken orthogonally in a weight-bearing position to enable 3D reconstruction of the lower limb. The inter- and intraoperator reproducibility has been studied and validated. The purpose of our study was to compare the inter- and intra-operator reproducibilities of the measures taken on the standard full-length x-ray and those determined on the 3D EOS reconstructions.

Material and method: Twenty-five patients scheduled for THA were included in this study (50 lower limbs). Two independent operators determine the measures on the AP EOS view and on the 3D reconstructions obtained from two orthogonal EOS images. The following parameters were measured: femur length, tibia length, limb length, HKA, HKS, femoral offset, neck-shaft angle, head diameter, and length of the femoral neck. Each observer performed two series of measurements. Interobserver reproducibility was assessed with the intraclass correlation coefficient (CI: 95%). Student’s t test was used to compare the clinical parameters measured on the 2D and 3D images.

Results: Inter- and intraobserver reproducibility were 0.867 and 0.903 on the 2D x-rays and 0.911 and 0.940 on the 3D reconstructions. The better reproducibility of the EOS reconstruction was confirmed for all parameters tested in this study. Comparison of the 3D and 2D measurements revealed significant differences.

Discussion: Our study demonstrated that measurements made on EOS 3D reconstructions offer better inter- and intraobserver reproducibility than those made on the standard AP view. In addition, the 3D reconstruction takes into consideration of the projection of the anatomic structures in the plane of the AP radiograph. The EOS appears to be a pertinent tool giving reliable results for the pre- and postoperative work-up for arthroplasty of the lower limb.


Jean-Yves Lazennec Alfonso Rangel Yves Catonné

Purpose of the study: The analysis of hip prostheses often remains limited to standard x-rays taken in the upright position or a CT scan taken in the supine position. The EOS® system enables imaging the entire body for head to foot in a lateral and anteroposterior views, in an upright or sitting position. The purpose of this work was to compare the standard radiographic work-up with the EOS system for the analysis of postural elements in patients with hip arthroplasty.

Material and method: This prospective study included 50 patients free of complications. The standard radiographic work-up included AP and lateral views in the upright and sitting positions. The standard then EOS imaging protocols were performed in two different locations. Images were acquired with the patients in a comfortable position: for the sitting position, the knees were flexed 90°. Two operators took measurements to be able to analyse reproducibility of the morphological parameters (incidence, sacroacetabular angle, and the positional parameters (version, sacral slope, Lewinnek angle, sagittal and frontal cup inclinations, pelvifemoral angle and orientation of the prosthetic neck on the lateral standing then AP sitting position). Pelvic rotation was determined on the AP view by comparative measurement of the projected width of the iliac wings in each pelvis. Hip extension reserve was calculated on the hyperextension lateral view.

Results: Reproducibility of position was excellent for different times and locations. Twelve hip (24%) presented significant reproducible rotation in the AP view; for eight of these hips (16%), the phenomenon disappeared in the sitting position. Four hips (8%) had pelvic rotation in the sitting position on the AP view. On the AP pelvic view in the sitting position, three patients had a femoral neck in functional retroversion while the anatomic femoral anteversion was normal on the scanner. The pelvic parameters were equivalent to those already described. The reproducibility of the measures was excellent between the standard x-rays and the EOS images with the exception of measurements involving the centre of the femoral head (incidence, pelvifemoral angle). It was easier to align the femoral axis on the EOS lateral images, particularly for additional calculation of extension reserve. The Lewinnek angle could not be measured in the sitting position in 32 hips (60%) because of insufficient resolution.

Conclusion: The overall evaluation of the pelvis and the subpelvic sector provides new information concerning the respective positions of the cup and the femur in functional situations.


Jacques-Marie Adam Jonathan Sfez Julien Beldame Frédéric Mouilhade Xavier Roussignol Fabrice Duparc Franck Dujardin

Purpose of the study: Radiographs of 24 patients who underwent surgery for total hip arthroplasty (THA) with a locked stem were reviewed at 38 months mean follow-up using a dedicated software. This software enables digital analysis of standard radiographs with semiquantitative evaluation of bone density.

Material and method: Good quality postoperative AP views of the femur and the same view at last follow-up were selected using the same criteria. These images were digitalised then analyses with the software. Bone density was established along a horizontal line 1 cm below the lesser trochanter perpendicular to the femur shaft. Computer analysis of bone density established three categories of patients as a function of cortical density: no cortical modification (n=5 hips), modification of only one cortical (n=11) and modification of both corticals (n=8).

Results: Bone density increased, suggesting improve cortical bone stock as has been reported by most authors using the transfemoral approach and a non-cemented locked stem.

Discussion: This result confirms the data in the literature; data which, unlike our series, were established on qualitative or subjective evaluations. The method presented here has the advantage of a semi-quantitative analysis, simple use, applicable to plain x-rays, and good reproducibility since all measures are made by the software. This study demonstrated the notion of cortical quality since it was not limited to a simple measurement of width, but also bone density, closer to real intraoperative observations.

Conclusion: Use of this method enables longitudinal study to establish the kinetics of bone remodelling, compare results between surgical methods, and search for factors explaining observed variations.


Julien Girard Donatien Bocquet Henri Migaud

Purpose of the study: Hip resurfacing (HR) is becoming popular again with the advent the the metal-on-metal bearing. This type of surgery is proposed for young, often very active, patients for whom restoration of optimal hip joint range of motion constitutes and important objective. The purpose of this work was to analyse anterior translation of the femoral component to optimise joint range of motion (particularly flexion).

Material and method: From September 2007 to May 2008, 68 hip resurfacing prostheses were implanted in 66 patients aged on average 45 years (range 19–61). All procedures were performed by the same operator using a posterorlateral approach and the same surgical technique. Anterior head-neck offset was a constant objective. The Postel-Merle-d’Aubigné and Harris scores as well as the Devane classification and the WOMAC and the SF-12 were noted. Joint range of motion was noted preoperatively and at last follow-up by and independent operator. Anterior head-neck offset was measured radiographically on the Dunn view using an original technique and calibrated by the Imagika software according to the known diameter of the implants.

Results: All clinical scores as well as the activity level and the subjective scores improved significantly. There were no revisions. The mean anterior head-neck offset was 4.5 mm (range 2–9). Significant correction was observed for gain in postoperative flexion and increased offset (p< 0.005). The group of patients who had an anterior offset considered to be significant (> 4 mm) exhibited significantly better flexion than the group of patients with a small anterior offset.

Discussion: Hip resurfacing has a poor head-neck ratio, depending on the patient’s anatomy, which compares unfavourable with conventional hip prostheses (THA). Nevertheless, the joint range of motion after resurfacing, as observed in our study and in the literature, does not show any decline compared with THA. The greater gain in flexion is an important factor to take into consideration, especially in a young active athletic subject. Each millimetre of gain in anterior offset produces a significant increase in flexion. This offset can be improved by the surgical technique (implanting the femoral component tangentially to the posterior cortical), but also by the design of the resurfacing prosthesis (thick femoral component, increased cement sheath). After hip resurfacing, anterior offset appears to be an essential biomechanical factor for restoration of joint motion.


François Lintz Christophe Pandeirada Philippe Boisrenoult Nicolas Pujol Olivier Charrois Philippe Beaufils

Purpose of the study: Conservative surgical treatment of osteochondritis dissecans (OCD) in adults raises the problem of integration of the sequestered bone. Mechanical techniques using screw fixation are often insufficient to achieve healing. Adjunction of a biological fixation with osteochondral graft tissue for a mosaicplasty might favour integration of the fragment. The purpose of this study was to assess the short-term outcomes in an initial series using a technique called fixation plus where screw fixation is associated with mosaiplasty.

Material and methods: This was a retrospective analysis of eight adults who underwent surgery from 2003 to 2008 for stage IIB or III (Bedouelle) OCD of the medial condyle. Loss of subchondral tissue could be filled with a cancellous graft. Clinical and radiographic (Hugston) parameters were noted. At three months, the screws were removed arthroscopically. The ICRS-OCD score was noted. At six months, five patients had an arthroMRI to evaluate fragment integration, determine its signal and vitality.

Results: Mean follow-up was 17.4 months (range 3–36). The Hugston score improved from 1.6 (0–3) preoperatively to 3.4 (2–4) postoperatively and the radiological score from 2.5 (2–4) to 3.2 (3–4). The arthroscopy performed to remove the screws revealed integration of the OCD fragment. The ICRS-OCD score was I in two cases, II in five and III in one. The postoperative arthroMRI confirmed continuity with the cartilage at the periphery of the fragment, with no passage of contrast agent into the defect.

Discussion: Screw fixation of OCD fragments is often followed by nonunion and thus failure. Moasaicplasty is an alternative but does not preserve quality cartilage cover (curvature, thickness, cover). The technique proposed here ensures osseous integration of he fragment, complete cartilage cover, and a smaller number of osteochondral pits. Fixation Plus associates mechanical and biological fixation with good preliminary clinical results. Comparative longer term assessment is needed to confirm its pertinence.


Sami Mezghani Philippe Clavert Jean Lecoq Marie-Eve Isner Renée Wolfram Jean-Luc Kahn

Purpose of the study: The piriform syndrome is treated medically: functional rehabilitation and injections. If the medical treatment fails, tenotomy of the piriform muscle can be proposed. Published studies report good outcome in 66 to 87% Of patients. The purpose of this study was to examine the extrapelvic innervations of this muscle in order to assess the feasibility of neurotomy of he piriform muscle.

Material and method: Twenty gluteal regions were dissected. We studied first the relations between the piriform muscle and the ischiatic nerve. Then the innervations branches of the piriform muscle were localized in three landmarks.

Results: We found the of the six types of relation between the ischiatic nerve and the piriform muscle described by Beaton, with frequencies comparable to reports in the literature. Innervation of the piriform muscle does not follow a standard pattern, even though the innervations generally comes from the ischiatic nerve; the nerve branches come from the superior and inferior gluteal pedicles. In addition, these nerve branches penetrate the deep aspect of the muscle in random fashion. In addition, accessibility to the deep aspect of the piriform muscle cannot be achieved easily but requires prior section of its insertion on the greater trochanter.

Discussion: In our opinion, these results suggest that isolated neurotomy of the piriform muscle is not clinically feasible; it might be possible to improve function results of isolated tenotomy by performing a neurotomy of the nerve branches visible during the tenotomy procedure. A greater benefit might be expected in forms where the ischiatic nerve crosses the piriform muscle.


Philippe Tracol Gérard Asenscio Jérome Essig Christian Nourissat

Purpose of the study: Implanting a femoral stem with a modular neck can modify the range and the position in space of hip rotation arcs. The purpose of this work was to evaluate changes in three versions of a modular neck and to define the determining criteria for the choice of the neck to implant.

Material and method: This series included 52 primary modular THA (ABGII) with ceramic bearings implanted with the HipNav 1.3 navigation system. The range of hip rotation were measured referring to the femoral saggital plane and the anterior pelvic plane. After insertion of the cup and the final ABGII stem and after choosing the length of the modular neck and the frontal inclination, the three different versions (retroversion −7, neutral 0 and anteverion +7) were tested. The range of hip rotation was measured by dynamic testing done under navigation. At the same time, the surgeon evaluated the stability and the absence of posterior impingement.

Results: In extension, mean range of rotation was 71° (102–123). It was modified by neck version. The position of the centre of rotation in relation to the reference rotation (rotation 0) depended on the version of the modular neck. The balance of the rotational arcs was better with a retroversed (−7) neck (mean centre of rotation -9) with a neutral neck (centre -13) or an ante-versed (+7) neck (centre-20). The determining factors were the version of the femoral stem and the combined (cup+stem) version. After checking the stability, the surgeon chose an anteversed neck in three cases (5.7%), a neutral neck in 25 (48%) and a retroversed neck in 24 (46.3%). The choice of the modular neck maintained the ligament balance in 71% of the hips.

Discussion: This demonstrates that the use of a prosthesis with a modular neck enables modulation of the rotational balance of the hip. This work demonstrates that work on balancing the rotational arcs of the hip in extension is a reliable operative criterion for choosing the version of the modular neck without using a navigation system.


Philippe Duchemin Arnaud Largey Wayan Hebrard Fanny Alkar Sébastien Trincat François Canovas

Purpose of the study: We analysed the clinical and radiographic outcomes of 113 cemented total knee arthroplasties (TKA) with resurfaced patella implanted in 83 patients with rheumatoid arthritis who were reviewed 1 to 12 years after implantation. Mean follow-up was 5.86 years. All implants were posterior stabilised (HLS) implanted by one operator using the same procedure.

Material and methods: One hundred seventy-two rheumatic arthritis patients underwent TKA from 1996 to 2007. At last follow-up, 68 could not be contacted, 11 had died, 9 declined review. The review was conducted in 2008 for 83 patients, 113 TKA. Female gender predominated (86.4%) and 29 patients (32.6%) had two TKA. Mean age at revision was 67.6 years.

Results: Seventy patients (84.4%) were satisfied or very satisfied with their prosthesis. The knee score (IKS) improved from 31.58 (0–63) preoperatively to 86.21 (59–99) postoperatively; the function score (IKS) improved from 31.7 (0–100) preoperatively to 77.12 (0–100) postoperatively. The improvement was significant for both scores. Men preoperative flexion was 97 (35–125) versus 112.1 (30–130) postoperatively. Ten knees presented anterior pain at revision (8.8%). The postoperative femorotibial mechanical angle was 180.72 (173–192). The mean femoral mechanical angle was 91.3 (78–99); the mean tibial mechanical angle was 89.4 (52–110). Men postoperative patellar height was 0.79 (0.24–2) measured with the Blackburn index. The patella was centred for 87.6% (99 knees) and subluxated laterally for 12.1% (14 knees). There were no loosening. Two arthroplasties had to be revised surgically (1.8%): one for infection (two-phase replacement with a hinged prosthesis) and one for patellar fracture treat by osteosynthesis. Two patients developed a postoperative phlebitis (2.4%).

Discussion: This study demonstrates the good mid-term outcomes achieved with a cemented posterior stabilised TKA in patients with rheumatoid arthritis. These results are nevertheless slightly less satisfactory than with TKA implanted for degenerative disease: this might be explained generally by disease-related impact on the functional result. Prosthetic surgery of the knee remains the treatment of choice for advanced arthritic degeneration.


Rémi Philippot Julien Chouteau Frédéric Farizon Bernard Moyen

Purpose of the study: From a biomechanical view, the medial force stabilising the patella is assured for 50 to 60% by the medial patellofemoral ligament (MPFL). The purpose of this cadaver study was to present a precise description of the anatomic features of the MPFL concerning its femoral insertion, its relations with the oblique vastus medialis (OVM) and its relation with the medial collateral ligament (MCL) in order to optimise surgical reconstruction.

Material and methods: This cadaver study was performed on 23 knees from fresh cadavers. All measures were made knee flexed 30° by the same operator. Insertions of the OVM on the MPFL, when present, were identified. The length of the zone of reflexion was recorded. For these measurements, a orthonormal landmark centred on the femoral insertion of the MPFL was established. This landmark was used to position the medial epicondyle and the adductor tubercle for each knee.

Results: The MPFL was found in all 23 knees (100%); the length of the MPFL was 57.7±5.8 mm; its femoral insertion measured 12.2±2.6 mm (8–136); its patellar insertion measured 24.4±4.8 mm. A junction between the OVM and the MPFL was found for all 23 knees (100%). This zone appeared to be a veritable reflexion zone with the OVM fibres arching over the MPFL fibres for a length of 25.7±6 mm.

Discussion: Our study confirms the constant presence of the MPFL, observed in 100% of the knees studied. During the reconstruction of the MPFL, the key point is the position of the femoral insertion of the ligament, in order to restore the native femoral insertion of the MPFL surgically and thus attempt to recreate perfect isometry of the graft. The graft must be positions 10 mm posteriorly to the medial epicondyle and 10 mm distally to the adductor tubercle. In our cadaver the MPFL, the main medial stabilising force of the patella was a constant finding, always located in the second thickness of the medial plane of the knee.

Conclusion: We detailed the native femoral insertion of the MPFL and described its relations with the medial femoral epicondyle and the adductor tubercle using an orthonormal landmark. Long-term function of the graft depends on proper positioning.


Mohamed Bouabdellah M. Bachir Karray Walid Akrout Abdelaziz Zarrouk Ramzi Bouzidi Khelil Ezzaouia Mondher Kooli Mongi Zlitni

Purpose of the study: In young adults, tibial wedge osteotomy performed for the best indications provides good results for about ten years. As these patients get older, knee arthroplasty may be necessary. The purpose of this work was to report operative difficulties and outcome after total knee arthroplasty performed in patients who had had a tibial osteotomy.

Material and methods: We reviewed 20 revision procedures where a posterior stabilised gliding total knee arthroplasty (TKA) was implanted after tibial osteotomy (closed wedge in general). There were 17 patients, mean age 71 years, sex-ratio 0.13; 82% of patients had cardiovascular histories and obesity was noted in 60%. The mean duration of the tibial osteotomy was 7 years. The mean IKS score was 31 and the mean function score 34. The patellofemoral joint presented signs of degeneration in all cases; the patella was low in 12 knees. Mean misalignment was 2 with > 10 varum in one knee and greater than 10 valgum in another. The anteromedial approach was used for 17 knees and the anterolateral approach for the other three. Osteotomy material was removed during the same procedure in five cases.

Results: There was one iatrogenic fracture of the tibial plateau with skin injury. At mean follow-up of 4 years (3–11 years), the mean IKS was 61 points and the mean function score 38. There was one aseptic loosening of the tibial plateau and one lat infection; there were 8 asymptomatic patellar subluxations and 14 low patellae.

Discussion: Tibial osteotomy with a closed lateral wedge for correction of major misalignment poses a difficult problem for subsequent prosthesis implantation. Difficulties include removal of the osteotomy material, the approach, ligament balance, and choice of the implant. Patellar complications can be avoiding by careful alignment of the height of the joint line and proper centring of the extensor system. The discordance between the function and joint score can be explained by the bilateral degenerative disease, by the cardiovascular history, and by the obesity noted in this series.

Conclusion: Tibial wedge osteotomy should be planned with the notion of possible future implantation of a total knee arthroplasty.


Philippe Hernigou Olivier Manicom Alexandre Poignard Redouane Jalil Georges Laval Patrick Dohn Razi Ouanes Julien Amzalla

Purpose of the study: In vivo kinematics of the knee joint (anteroposterior translation or rollback, axial rotation, elevation of the femoral condyle, range of motion) was determined for the knees of 30 subjects with a total knee prosthesis with a fixed or mobile plateau and also for the normal knees.

Material and methods: Videofluoroscopic images were recorded during gait and maximal flexion. An automatic 3D adaptation-modelling process was then applied to the fluoroscopic images to determine knee kinematics.

Results: For the normal knee, a certain degree of femoral rollback was noted for the lateral compartment (4.2 mm on average) while minimal translation was observed medially. The femoral rollback increased laterally during maximal flexion (14.4 mm on average) while the medial translation was minimal (1.5 mm on average). Thus, the average movement, which was not observed for all normal knees tested, was a pivot movement centred medially. The variability observed during maximal flexion was wide for all knee prostheses with a fixed or mobile plateau which do not have a stabilising system substituting for the absent posterior cruciate. During flexion, the normal knees exhibited mean 10° external rotation of the over the tibia. All of the rotational knee prostheses presented external rotation (mean 5°, ragne 0–10°). Inversely, the posterostabilised prostheses exhibited medial rotation of the femur over the tibia (mean 5°, range 0–10°), i.e. paradoxical movement.

Discussion: Unlike the normal knee where femoral rollback occurs during maximal flexion, paradoxical anterior translation of the femorotibial point of contact after arthroplasty, in particular in subjects with a fixed plateau prosthesis. For prostheses substituting for the posterior cruciate, femoral rollback involving the lateral condyle occurs regularly with minimal variability in the femorotibial contact point due to the regular engagement of the cam and cam follower mechanism during maximal flexion.


Stéphane Boisgard Stéphane Descamps Nicolas Miazzolo Benjamin Bouillet Jean-Paul Levai

Purpose of the study: The purpose of this retrospective study was to present the outcomes observed with the Cedior total knee arthroplasty (TKA), and in particular an embedded patellar implant fixed without cement and cemented titanium backed base plate with a press fit stem.

Material and methods: From January 1993 to December 1996, 155 TKA were implanted in 143 patients for degenerative disease of the knee joint. At last follow-up, 55 patients had died, 28 were lost to follow-up 14 were contacted by phone, and 46 were reviewed clinically. Mean age was 62 years (62–80), BMI: 29.9 (22.6–38.2). Mean follow-up was 12 years (10–13). Posterior stabilised implants were used for 33% of the knees and the posterior cruciate was preserved in 67%. For all knees, the thickness of the polyethylene was > 6mm. Outcome was assessed clinically with the IKS, WOMAC, and Charnley scores and radiographically on the basis f lucent lines, osteolysis, and residual misalignment as measured on the standard films and goniometry. Survival was determined with the Greenwood method.

Results: Two patients (2 posterior stabilised TKA) with residual varus > 6 (> 15 preoperatively) were revised for loosening. At last follow-up, the postoperative IKS was 164, the WOMAC 28. Two patients were dissatisfied. Radiographically residual alignment was less than 3 in 56%, 3 to 6 in 41% and > 6 in 3%. For the femur, there were two lucent lines in a single zone. For the tibia, six lines in zone 7, none around the stem. For the patella, two implants presented significant asymptomatic osteolysis and there were two spontaneous (5 and 8 years) and asymptomatic fractures. Survival was 98.1±4.6% for revision and 96.2±6.9% for aseptic loosening.

Discussion: Our results are comparable with 10-year outcomes published in the literature where the survival has ranged from 92% to 99%. The titanium back cemented under the bas without cementing the sanded stem provides satisfactory results. The two loosening occurred for a residual varus > 6. The embedded, non-cemented patellar implant gave satisfactory results but the two cases of osteolysis led us to propose cementing.


Julien Beldame Philippe Boisrenoult Philippe Beaufils

Purpose of the study: Navigated surgery for implantation of knee prostheses has demonstrated pertinence in terms of quality and regularity of the implantation. This technique requires insertion of rigid position captors in the bone during the operation. We report a series of five femoral fractures which occurred on the pin tracts in a consecutive series of 385 patients and analyse the causes and means of prevention.

Material and methods: This was a retrospective clinical and radiographic analysis of five patients among our consecutive series of 385 patients, who suffered fractures on navigation pin tracts.

Results: There were five femoral fractures, in four women and one man, mean age 73.2 years (65–79). The mean body mass index was 32.56 (24.15–39.45). The rate of this complication was 1.3%. The fractures occurred on average 12.6 weeks (range 7–21) after implantation of the prosthesis. The fractures were always preceded by thigh pain and occurred in a context of minor or indirect trauma. The fracture lines always started from a pin tract orifice. In four of five cases, the pins had been inserted in a diaphyseal zone and at least one was in a transcortical position. The five fractures healed with no functional sequel at last follow-up after osteosynthesis with a nail or plate and no complementary bone graft.

Discussion: The incidence of these fractures on navigation pin tracts is estimated at 1.3%. Surgeons must be aware of this complication and describe the risk to patients. These fractures occur late after the implantation, in obese patients, after an episode of thigh pain. Treatment requires stable osteosynthesis but does not compromise the knee prosthesis. These fractures are favoured by low and transcortical diaphyseal position of navigation pins. Prevention requires implantation of bicortical metaphyseal navigation pins. The development of pain in the thigh late after a knee prosthesis implantation, in a favouring context (obese patient, low diaphyseal pin orifice, transcortical tract) should suggest possible fracture requiring complete rest.


Bruno Tillie Régis Thomas François Quandalle Jean-Marc Leblanc François Bocquet

Purpose of the study: Insufficient patellar bone can raise problems for revision total knee arthroplasty and for certain cases of lateral patellofemoral degeneration. Several options are proposed: non-resurfacing, resurfacing on an asymmetrical bone cut, patellar thinning possibly leading to fracture, or patellar bone graft to obtain a regular thick bone.

Material and methods: We report a series of 26 patellar reconstructions among 19 primary osteoarthritis cases with lateral patellofemoral degeneration and five revisions. The patellar reconstruction involved the entire patellar surface in five cases and the lateral facet in 19. For only two cases, a bank graft was used. For the others, the graft was shaped from the tibial resection. Stabilisation used screw fixation in only one case. For the others, two cemented patellar anchor buttons were used to stabilise the graft. All patients were reviewed clinically and radiographically at minimum 12 months. Mean follow-up was 54 months (12–95).

Results: Patellar thickness measured during surgery was improved from 18.1 mm (10–25) to 24.5 mm (21–31). The DMS and function scores improved respectively: 45.5 and 40.7 preoperatively and 89.1 and 72.8 at last follow-up. Seven patients were noted C in the Charnley classification at last follow-up and five used one or two crutches for walking. Twelve patients used the hand rail when climbing stairs and seven needed to use their hands to get up from a chair. All grafts except the allograft fused and all patellar buttons remained stable. There was one lucency at last follow-up. Among the 13 patella exhibited a shift preoperatively, only one remained at last follow-up. There were no subluxations at last follow-up (15 preoperatively).

Discussion: This work shows the pertinence of patellar bone grafts to restore bone stock and avoid complications related to resurfacing asymmetry: pain and patellar shift. Fixation by osteosynthesis does not appear to be necessary. Autographs can be used without risk. Allografts still have to prove their efficacy in this indication.


Jean-Yves Jenny Matthieu Ehlinger François Bonnomet Jean-Henri Jaeger Jean-François Kempf

Purpose of the study: Revision total knee arthroplasty (rTKA) is becoming a routine procedure. The technical problems are greater than with a first-intention implantation because of the potential malposition of the initial implants, loss of bone stock, and prior ligament injury. It could be hypothesised that as for implantation of a primary TKA, navigation might improve the quality of the implantation.

Material and methods: We used the Orthopilot™ (Aesculap, RFA) navigation system for first-intention TKA. The standard software was used for revisions. The acquisition of the anatomic and kinematic data was performed while the initial implants in situ. The implants were then removed. Any bone recuts required were done under navigation control. The size of the implants and their thickness were determined after digital simulation of residual laxity; ligament balance was adapted from this data. The system does not allow navigation for centromedullary stem extensions nor for filling potential bone defects. Sixty patients underwent the procedure. There was a comparative series of 30 patients who underwent manual conventional revision using an instrumentation guided by the centromedullary femoral and tibial stems. The quality of the implantation was determined by measuring the alignment of the limb and the orientation of the implants on the postoperative x-rays. Outcome was analysed with Student’s t test and the chi-square test with p< 0.05 taken as significant.

Results: There was a significant improvement in quality of the implantation for all radiographic criteria in the navigation group. Limb alignment was restored in 88% of the navigated cases and 73% of the conventional cases. Similar differences were observed for femoral and tibial implant position on the lateral and AP views.

Discussion: The objectives set for implant orientation and ligament balance can be met with the navigation system for the majority of knees, with a rate similar to that achieved with primary implantation. The navigation system is an appreciable aid for these often difficult procedures where visual information can be misleading.

Conclusion: The navigation system used here facilitated revision TKA.


Jean-Michel Laffosse Martin Lavigne Julien Girard Pascal-André Vendittoli

Purpose of the study: Despite a survival rate to the order of 90–95% at ten years, implant malposition and particularly malrotation can cause an underestimation of failure after total knee arthroplasty (TKA). We report our experience with revision TKA for isolated malrotation.

Material and methods: Twelve patients underwent revision for isolated maltrotation of an implant. This series of three men and nine women, mean age 66 years, range 47–74 years at primary surgery, were reviewed retrospectively. During the follow-up, all patients complained of early onset anterior knee pain, which was generally noted severe, associated with moderate patellar instability in four cases, noted severe in 7 others and extreme in one (permanent patellar dislocation). Half of the patients also exhibited hyperlaxity was invalidating instability. Range of motion was generally preserved (2/5/100). In all cases, the rotational problems were confirmed on the computed tomography which revealed predominant tibial malrotation, measured at 23 mean internal rotation and a cumulative malrotation (femur+tibia) of 22 internal rotation.

Results: All patients except two required revision of both femoral and tibial implants. In one case, the tibial piece was alone changed and in another, isolated translation of the anterior tibial tuberosity was performed. For eight of eleven cases, the revision implants had a stem and femoral inserts were used to control the bone stock loss induced by the corrective cuts in six cases and requiring more or less extensive ligament balance procedures in six. At mean follow-up (30 months, range 12–60), there was a very significant improvement in the functional results; only one patients with a history of patellectomy complained of persistent anterior pain. None of the patients complained of patellar instability.

Discussion: Excessive cumulative internal rotation of the implants induces increased stress on the patella, causing early anterior pain, then subluxation and finally dislocation beyond −15 to −20° internal rotation. These position errors are concentrated on the tibia were care must be taken to respect the anatomic landmarks (bicondylar axis, anterior tibial tuberosity) to avoid early failure. In the event of major rotational disorders, revision may be required with procedures to correct the ligament balance.


Patrice Manopoulos Éric Havet Patrice Mertl Pacome Parizon Jean-François Lardanchet Michel De Lestang

Purpose of the study: Restrained implants with intrinsic stability guaranteed by a large central stem have been developed for revision knee arthroplasty, irrespective of the underlying cause. Successful restraint implies excellent fixation of the prosthetic implants which can be obtained using press-fit centromedullary stems. The purpose of this work was to assess the long-term results of this mode of fixation in this indication and to search for clinical correlations with potential radiological images around the stems.

Material and methods: We report 46 cases of Sigma®PFC TC3 revision total knee prostheses reviewed retrospectively at two years with a mean follow-up of eight years. Mean age at surgery was 68 years. Revision was indicated for aseptic loosening (n=24) and septic loosening (n=22). The knee society criteria were used for the clinical evaluation. Radiographic measurements were made semiautomatically with the Imagika® software.

Results: The mean clinical score improved from 42 points preoperatively to 84.7 at two years and 83.7 at last follow-up. Outcome was excellent (n=30), good (n=7), fair (n=1) and poor (n=1). The mean function score improved from 34.3 preoperatively to 69.1 at two years and 64.2 at last follow-up. Radiographic alignment was correct in all cases. The press-fit effect was observed for 63% of the femoral implants and 76% for the tibial implants. Around the stems, 57% of the implants exhibited condensation lines and 23% lucent lines measuring less than 2 mm. There was no relation between radiological findings and the clinical or functional scores. There were two failures, one for frontal instability at six years and the other for aseptic loosening at eight years. Excepting these two cases, there was one case of femoral implant migration with no clinical expression. For all other patients, the radiographic image remained unchanged between the two year check-up and the final follow-up.

Discussion: Thee presence of lucent lines or condensation lines is well known for this type of implant with long centromedullary stems. Nevertheless, this is the first clinical series evaluating the clinical impact of these radiographic images. In our opinion, these images are related to the relative mobility of these implants which should be checked regularly, although no long-term clinical expression occurs. For us, this type of implant enables good function and long-term stability.


Patrick Sportouch Pierre Étienne Benko Alain-Charles Masquelet Alain Yelnik Pierre Sylvain Marcheix Patricia Thoreux

Purpose of the study: The cervicobrachial outlet syndrome is an anatomic and clinical entity related to intermittent or permanent compression of the brachial plexus trunks, and/or the subclavian artery and vein as they pass through six successive spaces in the thoracic cervicobrachial outlet, including the intercostoscalenic space. The purpose of this work was to evaluate the feasibility of endoscopic exploration of the infra-clavicular portion of the outlet and the options for therapeutic interscalenic release.

Material and methods: Cadaver study of 12 shoulders: 3 male, 3 female.

dissection of the supra and infra-clavicular region (n=3) to identify zones of potential impingement and determine the structures constituting the outlet;

dissections (n=2) centred on the different zones considered as potential endoscopic portals;

endoscopies (n=2) via a supra-lateral clavicular approach followed by dissection;

endoscopies (n=2) via a supra-lateral clavicular approach followed by dissection with insertion of landmarks then a new endoscopy;

Endoscopies (n=3) via a supra-lateral clavicular approach to achieve intercalenic release followed by control dissection.

Results: The medial and lateral clavicular approaches identified two zones of less risk considering the proximity of the neck vessels and the phrenic and suprascapular nerves. A first, it was difficult to localize the brachial plexus endoscopically. This was achieved after dissection and insertion of landmarks. Five endoscopic procedures had to be performed to localize the plexus and starte the interscalenic release. Minute identification of the entry points for the trocars, as a perfect orientation of the instruments was necessary to achieve the procedure. The control dissections did not identify any vessel or nerve injury.

Discussion: Few data in the literature examine the question of endoscopic interscalenic release. Unlike Krishnan and Pinzer, we found that endoscopic exploration of the outlet at possible, but difficult, procedure. Use of an arthropump remains to be evaluated because of the distension and impregnation of the tissues. Insufflations with CO2 might be an alternative.

Conclusion: To our knowledge, a supra-clavicular approach for endoscopic exploration of the brachial plexus has not been described. Exploration of the outlet via this approach might be a less invasive procedure than conventional surgery. Complementary research is necessary to evaluate the morbidity of the different techniques.


Jacqueline Jan Tewfik Benkalfate Pierre Rochecongar

Purpose of the study: A systematic isokinetic assessment of both shoulders was performed in 103 men with shoulder instability subsequent to several anterior or antero-inferior trauma-induced dislocations. The assessment was part of the preoperative workup which included a clinical examination and an imaging protocol (standard x-rays + tomographies as needed). The purpose of the present study was to evaluate the force of the rotator muscles of the injured shoulder and to compare the findings with those obtained for the healthy shoulder. The objective was to determine the impact of instability on muscle balance in the injured shoulder.

Material and methods: This study concerned 103 men, mean age 24.8 years. The injured shoulder was dominant for 65 and non-dominant for 38. Time from the first episode of instability and the test was at least 2 months. One operator performed all tests using a unique dynamometer: Cybex Norm operating in concentric mode at 60 to 180/s.

Results: Overall, the results for 103 subjects at 60/s did not reveal any difference between the injured and the healthy side for internal rotators. There was a 2% deficit for the external rotators. At 180/s, the deficit was 5% for the internal rotators and 3% for the external rotators. For the injured dominant shoulders (n=65 subjects): at 60/s, there was no deficit; at 180/s, the deficit was 2% for internal rotators and 1% for internal rotators. For the injured non-dominant shoulders (n=38 subjects: the deficit was less than 10% compared with the healthy side for both 60/s and 180/s.

Conclusion: No significant deficit in internal or external rotation power was observed in the injured shoulder. Inclusion of an isokinetic test as a systematic part of the preoperative work-up for post-trauma instability in male subjects would not be warranted. The present findings can be used as control data for research involving non-trauma-induced uni- or multidirectional shoulder instability.


Pablo Vargas Miguel Pinedo Matthias Zumstein Jason Old Pascal Boileau

Purpose of the study: Posterior fracture-impaction of the humeral head (Hill-Sachs defect or Malgainge notch) is a well-known factor of failure for arthroscopic shoulder stabilisation procedures. Recently, Wolf proposed arthroscopic posterior capsulodesis and tenodesis of the infraspinatus, or what we call in French Hill-Sachs Remplissage (filling). We hypothesised that capsule and tendon healing within the bony defect could explain the efficacy of this arthroscopic technique.

Material and methods: Prospective clinical study of a continuous series. Inclusion criteria:

recurrent anterior instability (dislocation or subluxation);

isolated “engaged” humeral defect;

Bankart arthroscopy and Hill-Sachs remplissage;

arthroCT or MRI at least 6 months after surgery.

Exclusion criteria:

associated bone loss in the glenoid;

associated rotator cuff tear.

Twenty shoulders (20 patients) met the inclusion and exclusion criteria and underwent Hill-Sachs remplissage. Four orthopaedic surgeons evaluated independently the soft tissue healing in the humeral defect. Mann-Whitney analysis was used to search for a link between rate of healing and clinical outcome.

Results: Filling of the humeral defect reached 75 to 100% in 16 patients (80%°; it was 50–75% in 4 patients. Healing was never noted less than 50%. The short-term clinical outcome (mean follow-up 11.4 months, range 6–32) showed an excellent results as assessed by the Constant score (mean 92±8.9 points) and the Walch-Duplay score (91 points). The subjective shoulder value (SSV) was 50% preoperatively and 89% at last follow-up. There were no cases of recurrent instability. This study was unable to establish a relationship between minor healing and less favourable clinical outcome.

Discussion: This study confirmed our hypothesis that arthroscopic Hill-Sachs remplissage provides a high rate of significant healing in a majority of patients. Capsule and tendon healing in the humeral defect yields significant shoulder stability via at least two mechanisms:

prevention of defect engagement on the anterior border of the glenoid and

posterior force via improved muscle and tendon balance in the horizontal plane.

Further mid- and long-term results will be needed to establish a confirmed correlation between healing and clinical outcome.


Frédéric Picard David McDonald Angela Deakin Nick Scott Andrew Kinninmonth Nadine Willcox

Purpose of the study: Recent data in the literature regarding intra-articular deliver of analgesics during the postoperative period have been encouraging. Patients benefit from optimal analgesia and earlier mobilisation, shortening rehabilitation time and hospital stay and limiting complications. In light of these encouraging results, our institution developed a programme designed to address all postoperative situations associated with implantation of a total knee arthroplasty (TKA).

Material and methods: The programme combines pre-operative counselling and a postoperative programme for multimodal anaesthesia in addition to intra-articular analgesia for 24 hours and early mobilisation. We present here the results of this technique in patients undergoing first-intention TKA. We analysed information collected prospectively in all patients who had TKA from January to June 2008: 319 patients in six months. The operation was performed under peridural anaesthesia supplemented by intra-articular ropivacaine delivered by a catheter for 24 hours. Patients were mobilised, or verticalised, the day of surgery according to individual capacities. Data collected included: pain scores, date of the end of physical therapy, and data reviewed at six weeks.

Results: A cohort of 305 patients was analysed; 36% of patients were mobilised the day of the operation and 93% on day 2. The rate of urinary catheters was 12% and administration of intravenous fluids 10%. Physical therapists determined that 58% of patients could be discharged on 3 after surgery and 85% on day 5. Eighty-percent of patients were free of nausea or vomiting and had well controlled pain. Regarding function, mean range of motion was 85° at discharge with 31% of patients requiring physical therapy. At six weeks, mean range of motion was 95° and only 5% of patients had lost amplitude (reduction > 10° of range of motion) compared to discharge values. Mean scores on the Oxford questionnaire improved from 43 preoperatively to 26 six weeks postoperatively.

Discussion: This multidisciplinary approach guarantees excellent postoperative analgesia with early mobilisation and provides satisfactory results at six weeks. To this can be added the benefit of a lower rate of urinary catheters, administration of intravenous fluids, and physical therapy.


Lionel Neyton Bérangère Dawidziak Enrico Visona Jean-Philippe Hager Yann Fournier Gilles Walch

Purpose of the study: The purpose of this study was to report the clinical and radiographic outcomes a minimum five years after Latarjet-Patte treatment for recurrent traumatic anterior instability of the shoulder in rugby players. It was hypothesised that the Latarjet-Patte procedure fulfils the needs for shoulder stability in rugby players with anterior instability.

Material and methods: Thirty-four players (37 shoulders) were included. Mean age was 23.4 years (17–33). A bone lesion of the glenoid was noted in 73% of the shoulders, a humeral defect in 68%.

Results: Mean follow-up was 144 months (range 68–237). There was no recurrence (dislocation or subluxation). Apprehension persisted in five patients (14%). Sixty-five percent of the patients resumed playing rugby. Only one patient interrupted his sports activities because of the operated shoulder. The Walch-Duplay and Rowe scores were 86 and 93 points on average. The satisfaction rate was 94%. The block healed in 89% of shoulders (3 fractures, 1 nonunion). Twenty-six shoulders (70%) were free of degenerative disease, 11 shoulders (30%) presented stage 1 lesions.

Discussion: In rugby players, anterior instability exhibits characteristic bone lesions of the humerus and glenoid which can be identified as risk factors for recurrent instability. The Latarjet-Patte procedure provides a stable shoulder allowing resumption of rugby player for most patients with no long-term degradation of the shoulder joint. These results are in favour of our strategy to propose the coracoids block systematically for recurrent anterior instability in rugby players.


Pascal Boileau Numa Mercier Yannick Roussanne Jason Old Grégory Moineau Matthias Zumstein

Purpose of the study: The purpose of this study was to determine the feasibility and reproducibility of a new arthroscopic procedure combining a Bristow-Latarjet lock with Bankart reinsertion of the lambrum.

Material and methods: Forty-seven consecutive patients with significant bone defects in the glenoid and a deficient capsule were treated arthroscopically: arthroscopic Bankart had failed in six. The procedure was performed exclusively arthroscopically using a special instrumentation: after its osteotomy and identification of the axiallary nerve, the coracoids was passed through the subcapular muscle with its tendon; the block was fixed on the scapular neck after 90° lateral rotation so as to prolong the natural concavity of the glenoid. Anchors and sutures were then used to refix the capsule and the labrum onto the glenoid border, leaving the block in an extra-articular position. Follow-up included a physical examination and standard x-rays at 45, 90 and 180 days; 31 patients had a postoperative scan. Three independent operators read the images.

Results: The procedure was completed arthroscopically in 41 of 47 patients (8%); conversion to a deltopectoral approach was required for six patients (12%). The axillary nerve was successfully identified in all shoulders. The block had a subequatorial position in 98% (46/47 shoulders) and equatorial in one. The block was tangent to the surface of the glenoid in 92% (43/47), lateral in one (2%) and too medial (> 5mm) in three (6%). One patient presented an early fracture of the block and five patients exhibited block migration; there was a partial lysis of the block in two patients. The final rate of nonunion of the block was 13% (6/47). Fractures, migrations and non-unions were related to technical errors: screws too short (unicortical) and/or poorly centred in the block.

Conclusion: Our results show that arthroscopic transfer of the coracoids to the scapular neck is a safe and successful operation. The rate of correctly positioned healed blocks was equivalent or superior to conventional techniques. The complications observed show that the arthroscopic block technique is difficult with a long learning curve.


Rémi Charvet Blaise Michel Thierry George Frédéric Éloy Alain Blum Henry Coudane

Purpose of the study: The purpose of the study was to present the clinical and arthroscan results obtained in a prospective series of 32 patients who underwent Bankart arthroscopy. We wanted to identify concrete applications.

Material and methods: These 32 patients presented unidirectional anterior shoulder instability with a history of true dislocation. Unstable painful shoulders, multidirectional dislocations, and HAGL injuries were excluded as well as rotator cuff tears. An arthroscopic treatment was used in all cases, followed by the same rehabilitation protocol. All patients were reviewed at six months. External rotation (RE1 and RE2) and Gagey hyperabduction were noted as well as the Walch-Duplay, Rowe, and ISIS scores. Plain x-rays and an arthroscan were obtained preoperatively and postoperatively. Attention was focused on passage bone lesions, healing, and changes in volume of the inferior recessus after surgery.

Results: Mean follow-up was 17.1 months (range 6.5–31.3), mean age 26.3 years (range 17–46), sex-ration predominantly male: 4.3/1. Hyperlaxity was noted for 53.1% of the shoulders. The overall subjective result was unchanged since the conclusions at the 1993 SFA while the overall objective result improved. There was a significantly favourable absence of preoperative passage bone lesions. The negation of the Gagey sign and the decrease in external rotation were signs of restoration of effective capsule tension (p< 0.05) which was ofen associated with a decline in the volume of the inferior recessus, although the difference has not yet reached the level of significance.

Discussion: The very favourable results in cases free of preoperative bone lesions are in favour of early surgery, perhaps after a first dislocation. Negation of the Gagey sign and decreased external rotation are two simple reproducible postoperative signs useful for assessing the efficacy of anterior and inferior capsule tension; complementary imaging may not be necessary. Evaluation of the volume of the inferior recessus needs to be continued using a precise reproducible protocol taking into account for the rotation of the upper limb and the quantity of contrast product injected into the joint.

Conclusion: This study demonstrated results comparable with publications in the literature allowing a direct clinical application for postoperative assessment. Inclusion of new cases should confirm the pertinence of arthroscan measurement of the volume of the inferior recessus.


Dominique-François Gazielly Panayiotis Christofilopoulos Anne Lübbeke Alexandre Lädermann

Purpose of the study: The purpose of this retrospective clinical and radiographic study was to analyse the long-term results obtained after Patte’s triple locking procedure for the treatment of anterior instability of the shoulder joint.

Material and methods: A questionnaire was sent to 574 patients who underwent the procedure performed by the same senior operator from 1986 to 2006. Variables studied wer the Walch-Duplay score (with pain score), patient satisfaction, postoperative complications and radiographic aspect.

Results: One hundred fifty patients (26%) responded and sent three radiographs. There were 107 men and 43 women, mean age 28.6±8.7 years (range 16–57). Mean follow-up was 14.6 years (range 2.8–22.6). One hundred seventeen patients (78%) were reviewed with follow-up greater than 10 years. Two patients (1.3%) experienced recurrent anterior instability; no revision was required. The Walch-Duplay scores were excellent or good in 146 patients (97.3%); 53% of patients were pain free; 34% had episodic pain, 9% moderate to mild pain and 4% severe pain. Resumption of sports activity was noted by 85% of patients. Overall, 79% of patients were very satisfied, 18% satisfied, and 3% not satisfied. Postoperative complications (2%) were one case each of infection, transient paresis of the musculocutaeous nerve, and superficial venous thrombosis. There were radiographic signs of an anomaly of the coracoids block in 13 patients (8%); non-union (n=3), lysis (n=4) fracture (n=2), migration (n=1), fracture of the ceramic washer (n=3). The block or washer overhang was noted in 19 patients (12.7%). Centred osteoarthritis was noted in 31% of patients (25% Samilson 1, 4% Samilson 2, 2% Samilson 3). There were two factors associated with long-term degenerative disease: age > 40 at surgery (p=0.02 and block overhang (p< 0.01).

Discussion: Patte’s triple locking procedure is an open procedure for the treatment of anterior shoulder instability. The technique is very minute and specific postoperative rehabilitation is needed. In these conditions, the operation is effective, providing good control of shoulder stability and allowing resumption of sports activities with a low complication rate. This study shows that long-term degenerative disease can be decreased if the patient undergoes surgery before the age of 40 years and if the coracoids block does not overhang.


Charles Dézaly François Sirveaux Olivier Roche Frank Wein-Remy Nicolas Paris Daniel Molé

Purpose of the study: Several series have been reported on arthroscopic treatment of anterior instability. Few authors have focused on patient outcome after recurrent instability following arthroscopic stabilisation. Did these patients undergo revision surgery? What proportion? What were the results of secondary surgical coracoids block?

Material and methods: This was a retrospective analysis of 53 failures after arthroscopic stabilisation collected among a cohort of 182 patients who underwent surgery in our institution between 1988 and 2006. At last follow-up, shoulder function was noted using the Walch-Duplay score. The degree of joint degenerative disease was noted on the radiographs using the Samilson classification.

Results: Mean time to recurrence after arthroscopic stabilisation was 21 months (range 3–114). Patients were reviewed at mean 68 months. Twenty-four patients (45%° had not had revision surgery: 17 (32%) had declined a new operation and 7 (13%) had a unique episode of instability. Twenty-nine patients (55%) had revision surgery: 27 underwent an open procedure in our institution for a coracoids block. The revision was performed in another institution for two patients who were excluded from the analysis. Mean time between the two operations was 29 months. At last follow-up, 89% of the reoperated patients were satisfied. The mean Walch-Duplay score was 83.6/100 (activity=18.5; stability=15.9; pain=23.9; mobility=24.2). The Duplay score was 100 for 48% of the reoperated patients; 41% had persistent apprehension. Three patients (11%) developed recurrent dislocation at a mean 23 months (19–29). Among the 53 patients included in the study, 26% had moderate osteoarthritic lesions (Samilson 1 or 2). The reoperated patients were free of such lesions. Hyperlaxity, age, and sport practiced did not have any impact on surgical revision.

Discussion: In this overall series of 53 patients, 20 (37%) retained an unstable shoulder. Among them, 17 had declined new surgery. Eleven percent of the reoperated patients developed subsequent recurrence. This rate is higher than after first-intention blocks. Published series of arthroscopic revisions reported a higher recurrence rate (Kim, Arthroscopy 2002: 21 % recurrence; Neri, JSES 2007: 27 % recurrence).

Conclusion: The Latarjet block is the treatment of choice after failure of arthroscopic stabilisation, despite a high recurrence rate.


Alexandre Lädermann Barbara Mélis Panayiotis Christofilopoulos Gilles Walch

Purpose of the study: Reversed prostheses provide improved active anterior elevation in shoulders free of cuff tears by lengthening the deltoid and increasing is lever arm. The purpose of this work was to search for a correlation between arm lengthening and postoperative active anterior elevation.

Material and methods: One hundred eighty-three reversed prostheses were reviewed with minimum one year follow-up for a complete clinical and radiographic work-up. Using a previously validated protocol, arm lengthening was assessed either in comparison with the contralateral side or with preoperative measurements. A statistical analysis was performed to search for a correlation between lengthening of the humerus and the arm with active anterior elevation.

Results: Considering the entire series, mean lengthening of the humerus was 0.2±1.4 cm (range −4.7 to +5.4). Postoperative active anterior elevation was 141±27 (range 30–180). There was no correlation between humerus lengthening or shortening and active anterior elevation (p=0.169). A shorter arm produced an active anterior elevation at 121 and 0 – 1 cm lengthening an active anterior elevation at 140; lengthening 1 – 2.5 cm gave active anterior elevation at 144 and beyond 2.5 cm 147. The difference in active anterior elevation was statistically significant (p< 0.001) between patients with a shortening and those with a lengthening.

Discussion: Arm lengthening corresponds to a lengthening of the humerus plus a lengthening of the infra-acromial space. We found a statistically negative correlation between arm shortening (and thus deltoid shortening) and active anterior elevation and a positive trend between lengthening and active anterior elevation. Our measurement did not take into account the increased lever arm of the deltoid and thus only partially expresses the improvement in deltoid function. Nevertheless, our study shows that objective evaluation of deltoid lengthening is possible pre- intra- and postoperatively and that this measurement can be correlated with postoperative functional outcome.


Jean Kany Philippe Valenti Philippe Sauzières Denis Katz

Purpose of the study: A multicentric study involving ten centres of shoulder surgery collected a retrospective series of 45 patients treated for infection of a total shoulder arthroplasty.

Material and methods: Mean age was 68 years (range 28–88) with 2/3 male. The initial indication was excentred joint degeneration (37%), centred degeneration (5%), necrosis (7%), fracture (34%), excentration without degeneration (12%), rheumatoid disease (5%). The implants were a reversed total prosthesis (59%), a hemiprosthesis (26%), a total anatomic prosthesis (15%). Nineteen patients (46%) had a ‘naive’ shoulder at implantation of the first prosthesis, including 70% without any specific medical condition: 30% fracture (hemiprosthesis) and 50% reversed total prosthesis.

Results: The infection developed immediately after implantation in 76% of the shoulders (abnormal pain, hematoma, early collection, inflammatory scar, early fistula). The preoperative Constant score (26 points) showed pain at 4, function at 8, mobility at 12, and force at 2. Osteolysis was noted in 30%. The infection lasted less than 3 months before revision in 27%, 3 to 12 months in 68%, and more than 12 months in 5%. Blood tests were normal in two patients. Staphylococcus epidermidis was isolated in 29%, Propioni bacterium acne in 31%, and these two germs in 5%, but no germ was identified in 24%. There was no loosening in 69% of the cases, making the revision invasive. A one-phase procedure was performed in 31% of patients and a two-phase procedure in 25%. Repeated wash-outs were performed in 25%. A reversed prosthesis was implanted at revision in 87% of the shoulders. These revisions produced a 22% complication rate and 27% were revised for repeated wash-outs, instability or definitive en bloc resection. An infectious disease specialist was called in for 75% of patients; a two-drug i.v. regimen for 10 days was instituted followed by oral antibiotics for 3 months. Outcome was assessed with more than 24 months follow-up for 26 patients. The Constant score at review was 47 points (pain 12, function 12, mobility 20, force 4).

Discussion: Seventy-seven percent of the patients were considered cured at more than 2 years. The two-phase surgery, undertaken when the infection had lasted 3 to 12 months (40%) or more than 12 months (60%), gave a Constant score at 51% and 100% cure. The one-phase option undertaken for infections lasting less than 3 months (40%) or 3 to 12 months (60%) gave a Constant score at 46% and 50% cure. Simple wash-out required 60% revision (repeated wash-out, or implant replacement) and 67% cure. In the event of complications after revision, the cure rate was 67%. In all, only 6% of the patients were dissatisfied.


Thierry Haumont Anais Lemaire Audrey Ben Méliani Christine Henry Christian Beyaert Pierre Journeau Pierre Lascombes

Purpose of the study: Intramuscular injection of the botulinum toxin into the psoas can be proposed for permanent hip flexion due to spastic disorders. Several approaches have been described: retrograde subinguinal, anterolateral suprailiac, and posterior. Ultrasound or computed tomography can be used to guide needle position. These approaches are however limited to access to the L4 region, i.e. far from the motor points and with the risk of injury to the ureter. The purpose of this work was to determine the innervations of the psoas muscle that would be best adapted to this type of injection and thus to describe the most effective and reliable approach.

Material and methods: This anatomy study included 20 dissections to: describe vertebral insertions of the psoas major and the psoas minor and to measure their distance from the iliac crest; define the region where the ureter crosses in front of the psoas.

Results: More than 80% of the psoas muscles presented a proximal insertion on the transverse process of T12 and the body of L1; the mean length of the psoas in the adult is 27 cm above the inguinal ligament; the nerve roots collateral to the lumbar plexus are: 33% L2, 25% L3, 19% L1, 9% L4, 3% L5 and 1% T12, the remainder arising directly from the femoral nerve; the L2-L3 region is situated 4.6 cm on average above the iliac crest.

Discussion: The region facing the L2-L3 space enables access to more than 50% of the psoas nerve branches. Injection via a posterior approach situated in adults 4.6 cm above the iliac crest and identified fluoroscopically is the most reliable access. This will avoid injury to the ureter which lies lower.

Conclusion: This anatomy study described a new more effective less dangerous approach for botulinum toxin injections into the psoas muscle.


Ricardo São Simão Nuno Neves José Tulha Manuel Silva Rui Pinto Abel Trigo Cabral

Purpose of the study: Proximal fractures of the humerus account for 10% of fractures in persons aged over 65 years. There is no optimal treatment. The goal of surgery is to restore joint congruency, preserve vascular supply, and allow functional recovery. We describe the results obtained with a surgical technique designed to meet these goals.

Material and methods: Fifteen 3-fragment fractures of the proximal humerus were treated with transosseous suture. Mean age of patients was 58 years. Eighty-six percent of the patients were female. Follow-up was 18 months on average. The patients were placed in a lounge chair position for the deltopectoral or transdeltoid approach. For this type of fracture, the humeral head is displaced medially or laterally, so that care must be taken to ensure the realignment in the sagittal and coronal planes. The DASH and Constant scores were noted for the operated and non-operated shoulders. Signs of bone healing were noted on the plain x-rays.

Results: The mean DASH was 12, mean Constant score for the operated shoulder was 80 versus 90 for the other shoulder. The mean neck-shaft angle was 139°. There was one case of lost reduction but with a good final result. There was one case converted to arthroplasty.

Discussion: This technique is in line with the current trend for biological preservation minimising the aggression to the humeral head blood supply. There was no risk of migration with the fixation material used and no need to remove implants.

Conclusion: Transosseous suture of proximal fractures of the humerus is a mini-invasive method which provides good functional results avoiding voluminous metal implants, known to be costly and source of complications. The incidence of avascular necrosis of the humeral head is low, in agreement with the international literature.


Philippe Collin Solenn Gain Karl Chaory Christophe Lucas Gilles Candelier Michel Le Bourg

Purpose of the study: Therapeutic options for retractile capsulitis ranges from therapeutic abstention to arthroscopic arthrolysis. The purpose of this work was to examine the efficacy of a simple therapeutic option (arthrodistention + self-mobilisation).

Material and methods: This was a prospective study of a consecutive series of 41 patients (28 female, 13 male), dominant shoulder 57%. Inclusion criteria were deficient in passive range of motion ≥ 50% compared with the other side in at least two planes, without notion of trauma or surgery. Diagnosis and inclusion: one surgeon. Arthrodistension with corticosteroid injection: one radiologist. Recommendations for self-rehabilitation, the day of the arthrodistension: one physical therapist. Patients were reviewed at 30, 90 and 180 days to analyse pain (visual analogue scale, VAS), daily life activities (Constant score), range of motion.

Results: From day 1 to 6 months –VAS regressed from 5.8 (2 – 9) to 0.8 (0/2). Constant daily activity score improved from 1/4 to 3.6/4; FA from 82 (60/115) to 170; (150/180); Re1 from 5 (−10/30) to 50 (20/70); RI from 12 (0 – 30) to 30 (10/60). Recovery was correlated with deficit in RI (p< 0.005). The greater the RI deficit the less rapid the recovery.

Discussion: We did not use the overall Constant score because of the difficulty in evaluating force. An analysis of the literature shows that therapeutic abstention can provide recovery, but with a delay of about two years. Arthroscopic arthrolysis, interscalenic blocks provide a much quicker recovery (6 months). The results obtained here are comparable with those obtained with these more complex methods./

Conclusion: This study shows that a simple management strategy enables the same results as with more invasive and more costly techniques. The patient should be warned that an important deficit in RI will undoubtedly lead to a slower recovery.


Néjib Khouri Éric Desailly Farid Hareb Patrick Lacouture Jean-Paul Damsin

Purpose of the study: Spasticity of the rectus femoris (RF) in cerebral palsy patients is considered to be the main cause of stiff knee gait. The kinematics of this muscle, variations in length and speed of lengthening, are altered. Research is however lacking on changes in this parameter after surgery. Our objective was to study its effect on the quality of gait and on the kinematics of the RF in order to identify kinetic behaviour with diagnostic value.

Material and methods: Twenty-six transfers were performed during multiple level interventions. A uniform technique was applied: wide separation of the RF from the vastus muscles and supra-patellar tenotomy, suture of the RF tendon to the gracilis tendon tunnelled through the medial intermuscular partition. Intramuscular lengthening of the hamstrings (n=20) was associated with patella lowering procedures (n=4). The Gait-Deviation-Index (GDI) and the Goldberg score were determined pre- and postoperatively to quantify gait quality and search for stiff knee. A musculoskeletal model (virtual RF) was developed to simulate the trajectory of the RF during gait.

Results: The quality of gait improved (+18±12 GDI) with a negative interaction between the preoperative GDI and its improvement. For the Goldberg score, surgery yielded 88% improvement. Surgery had a significant effect on normalising the timing of RF lengthening and the maximal lengthening speed. Improvement in stiff knee was correlated with a normalisation of the timing of maximal length.

Discussion: Improvement in gait quality was greater when the preoperative quality is low; there is a risk of no improvement if the GDI is > 75. Normalisation of the timing of the maximal length of the RF is correlated with improvement in knee oscillation. Early timing signals a postoperative improvement in stiff knee. Early peak in the speed of lengthening of the RF can be explained by early triggering of spasticity during weight bearing which would limit the lengthening of the RF.

Conclusion: Global improvement of gait quality and stiff knee has been demonstrated. Certain muscular kinematic parameters are normalised, demonstrating the effect of transfer during oscillation but also during weight-bearing. Early peak in RF lengthening is a prognostic factor of successful surgery.


Yves Bouju Élodie Carpentier François Bergerault Benoit de Courtivron Christian Bonnard

Purpose of the study: Early and correct diagnosis of meniscal injuries in children is essential to preserve the meniscus and knee function. Often isolated, these lesions may be difficult to identify. The diagnostic procedure involves an excess of diagnostic arthroscopies and multiple series of magnetic resonance imaging (MRI) procedures performed by radiologists not specialised in paediatric diagnosis. The purpose of this study was to determine the concordance between MRI and arthroscopic findings in children with meniscal lesions.

Material and methods: This was a retrospective analysis of MRI series then arthroscopy performed on 96 knees in a paediatric population (age 9 – 17 years) explored between 1995 and 2008 for suspected traumatic meniscal injury. Discoid mensci were excluded. All arthroscopic procedures were reviewed by one operator and MRI by one radiologist familiar with paediatric pathology. All files were complete. Agreement with the arthroscopic findings (gold standard) was determined by the presence of a meniscal lesion, its localisation, and its type.

Results: Agreement reached 72% for presence or not of a lesion. It was 55% for localisation and 45% for type. In this context, the sensitivity of MRI was 85% with 42% specificity. There were 11 false positives and 7 false negatives.

Discussion: These figures are disappointing compared with those reported in the adult population (sensitivity 92% and specificity 87%) and express a decline in sensitivity, specificity and positive predictive value for MRI in children. The experience of a paediatric radiologist could improve the sensitivity of MRI in these situations.

Conclusion: This study shows that the agreement is not perfect for a suspected meniscal injury in children. MRI does not provide adequate diagnostic information and cannot be used for precise preoperative planning due to a lack of descriptive precision.


Mahtab Mehrafshan Raphaël Seringe Philippe Wicart

Purpose of the study: The anatomic, clinical and radiographic expression of congenital genu recurvatum corresponds to femorotibial subluxation. The clinical presentation can vary, ranging from an easily reducible subluxation to irreducible dislocation.

Material and methods: Fifty five patients (82 knees) were treated, mean age 2 days. Genu recurvatum was isolated (n=15 children), associated with hip dislocation or foot deformity (n=40 children), arthrogyrposis (n=10 children, or Larsen syndrome (n=3 patients). Were studied: anterior skin folds, anteroposterior femorotibial instability, joint range of motion at first exam and last follow-up. The Seringe classification was noted at birth: I – reducible (n=59 knees), II – difficult to reduce (n=12 knees), III – irreducible (n=11 knees). Mean follow-up was 4 years, 13 years, and 9 years for class I, II and III knees respectively. Orthopaedic treatment was performed in all cases with manipulations, braces, traction and plaster cast for at least 40 days. In the event of failure, a V/Y lengthening of the quadriceps was performed, associated with joint release.

Results: At the first exam, the skin folds were present in all cases in group I, 2/3 in group II, and absent in group III. Mean maximal flexion was 66, 43 and 17 respectively in groups I, II and III. The even operated knees were in group III. At last follow-up, the mean maximal flexion was 146, 124 and 77 respectively in groups I, II and III. Six knees presented anteroposterior instability in groups I, 3 in group II and 3 in group III. In group I, the final clinical outcome was good or very good in 55 knees (93%), fair in 4. In group II, good or very good outcome was noted in 8 knees (67%), fair in 3 (25%), and poor in 1 knee. In group III, outcome was faire in 4 (36%) and poor in 7 (64%). In this group, poor outcome corresponded to 86% of the operated knees.

Discussion: At the first exam, factors having the most unfavourable impact were: absence of an anterior skin fold, knee flexion < 50, irreducible femorotibial dislocation, and syndrome context. We emphasise the importance of adapted conservative treatment which, in our experience, provides the better clinical outcomes.


Camille Thévenin-Lemoine Mathieu Ferrand Pierre Mary Jean-Paul Damsin Nejib Khouri Raphaël Vialle

Purpose of the study: Variations in patellar height in relation to the trochlea and the joint line can be a cause of pain and instability and limit the range of knee flexion. The Caton and Deschamps index (CDI) was described and validated in a cohort of adult subjects. The purpose of this work was to validate this index and set the reference values in a paediatric population.

Material and methods: Lateral view of the knee were obtained in 300 patients who consulted for minor trauma without ligament or bone injury. Thirty patients, aged 6 to 15 years, were included in each age group (1-year groups). All radiographs were qualified as normal by the radiologist. Two series of measures were made in random order and at an interval of 8 days by two independent observers. The patellar height and the length of the patellar tendon were measured with computer assistance. The interob-server and intraobserver variabilities were determined.

Results: The mean patellar height was 33.39±7.40 mm. The mean length of the patellar tendon was 34.57±67.36 mm. The mean CDI was 1.06±0.21. There was not significant correlation between patient age, height of the patella and length of the patellar tendon. Thus the height of the patella and the length of the patellar tendon increased with age while the CDI was statistically lower in older patients. The height of the patella was identical in the two genders while the patellar tendon was statistically longer in boys. The CDI was statistically higher in boys. Interobserver and intraobserver agreement was excellent.

Discussion: CDI is a simple and reproducible measurement in adults and in children and adolescents. During growth, it is an alternative to the Insall index which has limited reproducibility and the Koshino index which is difficult to use in routine clinical situations. We found a correlation between CDI and children’s age, related to progressive ossification of the patella.

Conclusion: The CDI is a tool which can be used in routine practice to study patellofemoral problems in the paediatric population as long as the physiological values are weighted by age.


Lionel Wasser Gorka Knorr Franck Accadbled Abdelaziz Abid Jérome Sales de Gauzy

Purpose of the study: For symptomatic discoid meniscus, the treatment of choice in children is arthroscopic meniscoplasty. The treatment of associated meniscal lesions remains a subject of debate. The purpose of our work was to evaluate our results with arthroscopic meniscoplasty associated with meniscal repair as needed and the findings of the systematic postoperative MRI.

Material and methods: This was a retrospective series of patients treated by one operator. There were 23 discoid menisci (21 patients) treated from 2004 to 2007 with arthroscopic meniscoplasty followed by a complementary procedure depending on the residual meniscus: abstention if there was no associated lesion, suture or reinsertion for reparable lesions, partial meniscectomy for non-reparable lesions. The Lysholm and Tegner scores, plain x-rays, and MRI were obtained systematically.

Results: Mean age at surgery was 9.8 years. The Watanabe classification was I:9, II:9, III:5. Arthroscopy revealed 15 lesions, including 11 longitudinal tears. Meniscoplasty was performed in 9 cases alone, associated with partial meniscectomy in 6 and with repair in 8 (5 cases of disinsertion and 3 tears). Mean follow-up was 37.1 months. The mean postoperative Lysholm was 87.9, the Tegner 5.9. Outcome was considered satisfactory or very satisfactory by 90% of patients. MRI failed to reveal any signs of chondral degeneration or meniscal tear. There were however four cases of high intensity intra-meniscal signals and one meniscal cyst. Mean measurements of the residual meniscus were: anterior segment 8.6 mm thickness and 2.6 mm height; middle segment 5.5 and 2.3 mm; posterior segment 5.8 and 3.0 mm. One case of osteochondritis of the lateral condyle was noted postoperatively.

Discussion: To our knowledge, there is no other study evaluating the outcome of discoid meniscus surgery with postoperative MRI. There have been few reports concerning meniscoplasty then repair. This approach spares meniscal tissue, essential for children. We obtained good clinical results and patient satisfaction. At the MRI, the residual meniscus had a morphology close to normal. There were no signs of tears. The high intensity signals occurred in patients with good outcome.

Conclusion: Arthroscopic meniscoplasty associated with repair or partial meniscectomy as needed appears to be a good therapeutic solution for discoid meniscus in children.


Virginie Rampal Raphaël Seringe Philippe Wicart

Purpose of the study: The purpose of this work was to study outcome at the end of grow after surgical treatment for idiopathic congenital equinovarus club foot.

Material and methods: From 1983 to 1991, 63 children (85 club feet) given functional treatment underwent surgery because of insufficient results. At birth, the Dimeglio classification was II:11.7%; III:40%; IV:25.8%. Surgery was performed before the age of 2 years for 52 fee (61%) and after 2 years for 33. The indication for surgery was a triple deformity: equin (8.1±15.2, varus (8.2±13.1, adductus (32.5±13.8). Surgery was associated as needed with posterolateral release (94.1%), anteromedial release (92.9%), plantar release (61.1%) and Lichtblau shortening of the lateral column (42%). The tendon of the tibialis anterior was lengthened for 86% of the feet. Functional, clinical, and radiographic outcomes were noted at last follow-up.

Results: Mean follow-up was 15 years (8–22). Fifteen feet (17.6%) had a second operation: 13 for recurrence (repeat release), one for over correction (lengthening of the calcaneum) and one for metatarsus adductus (metatarsal osteotomies). One foot had a third operation for recurrence (repeat release). Three feet (3.5%) did not have surgery; a double arthrodesis followed progressive aggravation during growth. In the first group (surgery before 2 years), outcome was very good, good or fair for 76.9, 17.3 and 5.8% of the feet. The “fair” outcomes concerned three children who had more than one operation. In the second group (surgery after 2 years), the outcomes were 78.8%, 18.2% and 3% (n=1) respectively. The “fair” result concerned the double arthrodesis. There was no significant difference for the final outcome as a regards age at surgery (p=0.07). Among the four feet with a “fair” outcome, two were initially Dimeglio III and two Dimeglio IV.

Discussion: Soft tissue release enables correct results at the end of growth for the majority of these club feet. While the Dimeglio score is an element predictive of an indication for surgery, it is not a prognostic element for the final outcome. Age at surgery does not have a significant impact on the final outcome.


Dimitri Popkov Pierre Lascombes Pierre Journeau Andrei Popkov Thierry Haumont

Purpose of the study: There is a link between complications and duration of instrumentation. Since 2001, we have associated circular external fixation (EF) and stable elastic centromedullary nailing (SECMN) to shorten the duration of the external fixation in bone lengthening in children. This study was designed to assess the results of the EF+SECMN for this indication.

Material and methods: From 2001 to 2009, progressive bone lengthening was performed in 250 children aged 3 to 16 years. There were 295 progressive lengthening procedures involving 339 segments. Indications were congenital (n=163) and acquired (n=87) length discrepancy. In group I (195 lengthenings, 222 segments), the Ilizarov EF was used alone. In group II, the Ilizarov (n=92, 108 segments) or the TSF (n=8, 9 segments) EF was associated with SECMN. After insertion of the EF, the centromedullary nails were introduced after the osteotomies. The healing date was the date the EF was removed; the nails were left in place to protect the bone. The healing index was calculated from duration of the EF (in days) divided by lengthening (in cm).

Results: Use of SECMN shortens the duration of EF irrespective of the aetiology, the segment, the lengthening method (mono- or polysegmental, mono- or poly-focal), with a statistically significant difference between the two groups (gain of 6 to 12 d/cm). In group I, deformities or fractures of the regenerated bone after removal of the EF occurred in 21 cases (10.77%), deep infections in 4 (2.05%), osetomyelitis in 2 (1.03%). In group II, the only complications were late healing (1%) and 10° angulation at the lengthening site (1%). The centromedullary nails migrated in eight patients, with no impact on the lengthening results.

Discussion: With SECMN, the lengthening procedure is achieved with an elastic but resistant system. It is hypothesised that this system stimulates osteogenesis since the healing index is improved. SECMN does not prevent progressive correction of shaft or diaphyseal deviations. By shortening the duration of external fixation, this method had a great impact on reducing serious complications such as fractures and deep infections.

Conclusion: SECMN can considerably reduce the duration of external fixation during bone lengthening procedures in children and reduce (or eliminate) most of the serious complications.


Alexandre Roux Jean-Marc Laville Virginie Rampal Raphaël Seringe Frédéric Salmeron

Purpose of the study: Among the causes of secondary congenital equinovarus club foot, neurological disorders predominate. The entity we examine here corresponds to irreversible pure motor paralysis with no sensorial disorder affecting the lateral compartment predominantly and sometimes associated with involvement of the anterior compartment. There is no literature on this entity. Beyond the question of the aetiology, the demonstration of this pathological condition can modify therapeutic strategy in order to prevent recurrence.

Material and methods: We examined 42 congenital equinovarus club feet with persistent pure motor paralysis involving the lateral compartment and sometimes the anterior compartment with a mean 10 years follow-up. The Dimeglio classification was used and an analytical muscle score was noted for each patient. Complementary tests included an electromyogramme when possible. Conservative treatment was the rule either using a functional method or the Ponseti method; surgery was then proposed when necessary for posteromedial release with or without palliative muscle transfer. The following procedures were performed: posteromedial release (n=33) and muscle transfer (n=26): tibialis posterior (n=22), tibialis anterior (n=3); hemisoleus (,n=1); tibialis posterior associated with flexor digitorum longus (n=3).

Results: Conservative treatment was used for all feet but all presented recurrence and required secondary surgery (33 posteromedial releases and 26 muscle transfers).

Discussion: This study opens the discussion on the similarity between idiopathic and arthrogryoposis club foot since the electromyography sometimes reveals an anomaly of the anterior horn. Thus club foot with pure motor and persistent paralysis involving the lateral and/or anterior compartment will not respond sufficiently to nocturnal contention if an adapted muscle transfer is not associated.

Conclusion: Muscle transfer to reactivate dorsal flexion of the foot enables a better functional outcome. First intention conservative treatment can be instituted while waiting for potential recovery. If the paralysis persists beyond one year, muscle transfer is indicated before the deformity recurs and requires an associated posteromedial release.


Franck Chotel Aurélien Scalabre Frédéric Hameury Pierre-Yves Mure Perrine Marec-Bérard Jérome Bérard

Purpose of the study: Malignant tumours of the thoracic wall are rare. Treatment protocols include extensive surgical resection. In children, these resections can generate very severely progressive scoliosis. We studied the local conditions favouring the development of scoliosis in a consecutive series of eight patients.

Material and methods: From November 2004 to December 2007, six boys and two girls, mean age 7.6 years (range 4 months – 15 years) underwent extensive thoracic wall resection for a malignant tumour: Ewing sarcoma (n=5), spindle-cell sarcoma (n=2), neuroblastoma (n=1). All patients received adjuvant chemotherapy followed by resection removing on average 3.1 rigs (range 1 – 4 ribs). Six resections involved the costovertebral angle and three were associated with partial pneumonectomy. The number of ribs resected was noted in Roman numerals. The thoracic wall was divided into three sectors in the horizontal plane according to the level of the resection (A, B, and C, posteriorly to anteriorly). Reconstruction was achieved with a Gortex plaque (n=1), Borreli staples (n=2). Posterior spinal instrumentation was performed in one patient. Despite in sano resection, six patients underwent postoperative radiotherapy.

Results: At mean 2.9 years follow-up (range 1 – 5 years), four patients of the eight developed scoliosis convex on the operated side. These patients had IVA resections for three patients (50, 50 and 32° scoliosis) and type IA-IIB for one patients (13° scoliosis). These deformities occurred despite a corset and instrumentation in one patient. None of the patients had a humpback. Patients who did not develop scoliosis had resections IA-IIB, IA-IB, IVC and, IC.

Discussion: The type of reconstruction, the histological type, use of complementary postoperative radiotherapy or pulmonary resection did not appear to be factors favouring the development of scoliosis. Conversely, resection in zone A (posterior) over more than two adjacent levels, might be a predictive element of the risk of scoliosis.

Conclusion: In the event of a resection of ribs in a posterior zone over more than two levels for resection of a malignant tumour, posterior instrumentation should be discussed. This preliminary work offers evidence for thought but needs to be strengthened with a multicentric study to enable a statistical analysis.


Delphine Claus Emmanuel Coudeyre Pascale Givron Fabienne Riaux Bruno Aublet-Cuvelier Jean Chazal Bernard Irthum

Purpose of the study: Evaluate the impact of an information brochure on residual functional incapacity after lumbar discectomy for common lumbosciatic pain.

Material and methods: A biopsychosocial information brochure on the management of chronic pain was developed on the basis of evidence-based medicine. A prospective randomised controlled trial was conducted to assess its impact. One hundred twenty-nine patients were included. The intervention group (GI) was given the biopsychosocial brochure entitled “You have had a back operation” (Vous venez d’être opéré du dos) while the control group was given a biomedical brochure. The information content was the only difference between the two groups; the patients were not informed of their randomisation group. The main outcome was functional incapacity at two months (Quebec scale). The duration of return to usual daily and occupational activities was noted at two months. Secondary outcomes were fears and beliefs measured by the FABQ and the BBQ before and after information delivery and at two months. Radicular and low back pain were evaluated using a numerical scale. Satisfaction with information received was determined. All demographic and clinical data were collected with self-administered questionnaires.

Results: Functional incapacity at two months declined more in GI: 32.4±22.8 versus 36.1±18.7 in the control group (p=0.36). The biopsychosocial brochure favoured resumption of usual physical activity: since 2.38±2.47 weeks in GI versus 1.00±1.28 weeks in the control group (p=0.0006) and of occupational activity: 2.35±1.17 weeks in GI versus ±Discussion: in the control group and for significantly more patients in GI (p=0.02). Fears and beliefs measured by the FABQPhys declined significantly in GI: from 15.9±6.3 to 8.0±7.14 versus from 14.1±5.6 to 11.23±6.34 in the control group; this score remained lower in GI at two months: 8.64±7.6 versus 10.63±7.2 (p=0.18). The patients in GI were significantly more satisfied with the information received.

Discussion: Reading the biopsychosocial brochure had a significant impact on functional incapacity in terms of time to resumption of physical and occupational activities and enabled a reduction in fears and beliefs.

Conclusion: This information brochure is an interesting tool for healthcare professionals and contributes to therapeutic education of patients.


Frank Fitoussi Brice Ilharreborde Olivier Badelon Philippe Souchet Keyvan Mazda Georges-François Pennecot Alain-Charles Masquelet

Purpose of the study: Resection of a malignant primary tumour of the proximal humerus implies sacrifice of a large part of the humeral shaft and the periarticular muscles. Reconstruction can be difficult and raises the problem of preserving function. Recent work has demonstrated the pertinence of combining a glenohumeral prosthesis with an allograft. Several complications are nevertheless reported: non-union, allograft resorption, loosening. We report three cases of malignant primary tumours requiring wide resection of the humerus which were treated by reconstruction with a shoulder arthrodesis applying the induced membrane technique.

Material and methods: Three patients (mean age 15 years) presented a malignant primary tumour of the proximal humerus (Ewing sarcoma or osteosarcoma) which was locally extensive but not metastatic. Resection implied resection of 16 cm of the humerus (mean). The same procedure was used for the three patients: first phase: wide resection of the tumour and neighbouring soft tissues which removed the majority of the proximal end of the humerus and the glenohumeral joint, then insertion of a cement spacer; second phase: reconstruction with a shoulder arthrodesis using cancellous grafts positioned inside the induced membrane. Stabilisation was ensured by insertion of a non-vascularised fibula inside the membrane and with a plate fixation on the scapular spine.

Results: Mean follow-up is five years. There has been no local recurrence and no distant spread. The arthrodeses and the reconstructions healed without reoperation within six to eight months. The functional outcomes were not different from those obtained with shoulder arthrodesis with a mean elevation of 90°.

Discussion: There are many advantages of reconstruction with shoulder arthrodesis using the induced membrane technique: possible wide initial resection, more satisfactory carcinological resection, the periarticular muscles are not pertinent after arthrodesis; there is no need for prosthetic elements or an allograft exposing to later complications; the reconstruction time is a simple procedure; elevation remains satisfactory.

Conclusion: This technique should be included in the surgical armamentarium just like vascularised transfers, allografts and massive prostheses. The indication should be reserved for extensive resection.


Amir Hariri Philippe Wicart Michel Germain Jean Dubousset Eric Mascard

Purpose of the study: Transfer of a vascularised fibular is an option after tumour resection to save the limb.

Material and methods: Thirty-eight consecutive cases of malignant bone tumours located in the shaft of long bones of the lower limb were treated with a free transfer of a vascularised fibula. There were 30 femoral localisations and 8 tibial localisations, 32 first-intention transfers and six transfers after failure of an allograft. Mean age at transfer was 11.8 years (range 4.33–22.57). Adapted chemotherapy was associated. The Musculo-skeletal Tumour Society score was noted for the functional assessment. Healing was considered achieved when there was a bone bridge between the transplant and the recipient bone associated with disappearance of the osteotomy line. Outcome was expressed as mean or percentage with the 95% confidence interval. P< 0.05 was considered significant.

Results: Mean follow-up for the 38 patients was 7.56 years (range 0.37–18.4). The mean MSTS was 27.2 (range 20–30).. This mean score was significantly higher (S t = 2.11> 2.04) for vascularised fibular transfer surgery immediately after tumour resection (27.4) than after revision surgery (25.4). The healing rate was 89%. The rate of healing failure of the vascularised free transfer was significantly greater (p=0.005< 0.05) after revision (33%) than after immediate transfer (6%). The rate of good results in the Boer classification was significantly higher for tibial than femoral reconstructions (p=0.006< 0.05), for immediate surgery than revision surgery (p=0.005< 0.05), and for Ewing tumours than for osteosarcoma (p=0.0019< 0.05).

Discussion: Free transfer of a vascularised fibula is a reliable reconstruction technique for bone shaft loss of the lower limb after resection of a malignant bone tumour in children. This is a mutilating surgery with frequent complications but which can save the limb. This reconstruction surgery should be done at the same time as the resection. Healing of the vascularised fibular transplant is more difficult to achieve for femoral reconstructions than tibial reconstruction and there are more complications in the femoral localisation. Femoral reconstructions using a vascularised fibular transplant should be associated with an allograft.


Vincent Fière Alexis Faline Guillaume Greiff Pierre Bernard

Purpose of the study: ACDF is the cervical surgical technique the most widely used for the treatment of severe discopathy in rugby players. Different techniques have been applied, with no real consensus for the technical procedures or the postoperative rehabilitation. The goal is to normalise the surgical treatment and rehabilitation for elite rugby players who have had a cervical fusion for discopathy with the objective of resuming rugby three months postoperatively.

Material and methods: This was a retrospective study including 85 high-level rugby players (professional and semi-professional players) operated on by three surgeons from 2003 to 2008 for one or two levels presenting discal herniation (levels C3 to T1) with cervicobrachial nevralgia unresponsive to conservative treatment. Postoperative function was assessed with the cervical handicap index, a visual analogue scale for pain, consumption of analgesics, and possibility to resume rugby at three months. Flexion-extension radiographs of the cervical spine were obtained. All patients underwent ACDF using a Peek cage filled with autologous iliac bone fixed with a plate or a compressive staple. The patient completed a self-administered satisfaction questionnaire during follow-up. The radiographs and the clinical exam were done by an independent observer (GG).

Results: Mean follow-up was 26 months (4–55). Mean operative time was 50 minutes (30–70). Mean hospital stay 2.3 days (1–3). There was no difference between plate and staple fixation. There were no major postoperative complications. Fusion was radiographically achieved in all cases. All patients played competition rugby three months after surgery. At last follow-up, seven players had interrupted rugby playing for personal reasons or for other intercurrent medical conditions. Seventy-eight percent stated their clinical situation had improved and that they were satisfied.

Conclusion: The results of this series confirm the pertinence of this method to achieve effective fusion authorising resumption of rugby playing three months postoperatively. Use of a Peek cage filled with autologous bone and stabilised with fixation appears to be necessary to allow rapid functional rehabilitation exercises using a programme of three phases of one month. The normalisation of the treatment for sever cervical discopathies in the high-level rugby player appears to be possible and safe, compared with data in the literature.


Alain Meyer Hugues Pascal-Mousselard Marc-Antoine Rousseau

Purpose of the study: Progressive cervical myelopathy secondary to cervical stenosis is generally treated surgically. Results of surgical decompression are generally good, but the progression and the type of neurological recovery have not been studied. We followed a cohort of patients who underwent cervical decompression in order to study the kinetics and the mode of the neurological recovery after surgery.

Material and methods: This was a prospective mono-centric observation study conducted in a routine clinical setting. The cohort included 60 patients (mean age 65.7 years) who underwent surgery around 2006. Inclusion criteria were an association of stenosis documented on the imaging and clinical signs of medullary compression. One surgeon performed all interventions (80% posterior approach, 15% anterior and 5% mixed). Preoperative evaluation used complete cervical imaging and three validated function tests: the global JOA score, the Crockard walking test, and the nine-hold plug test of manual dexterity (9HPT) for both hands. Patients were reviewed postoperatively at 1, 3, 6, 12, 18 and 24 months. Two populations were distinguished: group 1 with mild to moderate compression: mean preoperative JOA > 10; group 2 with severe compression: mean pre-operative JOA ≤10.

Results: The mean preoperative JOA was 11.7/17 (5; 15), the mean Crockard 34.5s (24; 140), and the mean time for the 9HPT 23s for both hands. Analysed by group according to the JOA showed that cervical myelopathy is mainly expressed by sensorial disorders. The JOA score, the walking test and the hand dexterity test for the dominant hand described the same pattern of recovery with a clear improvement for the first three postoperative months then a neurological stabilisation of the acquired improvement on a plateau that persisted till the end of follow-up. There was no improvement in the non-dominant hand. The same pattern was observed in both groups: the severe group presented a better improvement, reaching a final JOA score equivalent to that in the “mild-to-moderate” group.

Discussion: The pattern of recovery of cervical neurological deficits occurs rapidly during the first three months following surgical decompression, then stabilises on a plateau, irrespective of the severity of the initial condition. The benefit is certain for initially severe compression.


Thibaut Lenoir Marc Sabourin Cyril Dauzac Pierre Guigui

Purpose of the study: It is currently accepted (particularly since the work by Katz et al.) that a number of factors can potentially influence the functional outcome obtained after surgical treatment of lumbar canal stenosis (LCS). Among these factors are comorbid conditions and the notion of perceived health appear to be predominant. Little work has however been focused on the influence of these same factors on the qualitative and quantitative expression of functional impairment expressed by patients before their treatment. This possible link might have an intrinsic impact on the assessment of the outcome obtained after medical or surgical treatment of LCS. We wanted to examine this question.

Material and methods: Two hundred twenty patients referred to our orthopaedic surgery consultations were included in this prospective observation study, irrespective of the type f treatment eventually proposed (medical or surgical) or the type of lumbar stenosis. Patients who had had prior spinal surgery and those treated for LCS due to spinal deformity were excluded. The degree of the functional symptoms was determined with the SF36 and a self-administered questionnaire specifically designed and validated for the evaluation of LCS. Comorbidity factors were studied individually and with the following scores: the ASA score, the FCI (Functional Comorbidity Index), the CIRS (Cumulative Illness Rating Scale, and the ICED (Index of co-existent Diseases). Univariate and multivariate analysis was used to search for correlations between expressed functional impairment and comorbid factors.

Results: Expression of a functional impairment was significantly associated with a high number of comorbidity factors. This correlation was tighter when there was no additional compressive discal factor and when the functional neurological symptoms were longstanding. The type of comorbid factor analysed did not have an impact on these results

Conclusion: The presence of comorbid factors is significantly associated with more severe expression of functional impairment related to LCS. This effect could also influence the functional outcome after treatment of LCS and should be taken into consideration.


Thibaut Lenoir Ludovic Rillardon Cyril Dauzac Pierre Guigui

Purpose of the study: Although the iliac autograft is the gold standard for single-level intervertebral fusion, complications and morbidity related to autologous graft harvesting from the iliac crest remain a point of concern. Bone morphogenic protein (BMP) has proven advantages for fusion of the intersomatic and posterolateral graft. This study compared the efficacy and tolerance of OP-1 compared with an autologous graft in patients with symptomatic spondylolisthesis. This study reports the preliminary results of a prospective randomised controlled trial comparing OP-1 with an iliac autologous graft for instrumented single-level posterolateral fusion for arthrodesis of grade 1 spondylolisthesis.

Material and methods: Lamino-arthrectomy associated with a posteriolateral instrumented arthrodesis with an iliac autologous graft or a mixture of OP-1 and local autologous graft material was performed in 27 patients with spondylolisthesis leading to lumboradiculalgia or neurogenic claudication. The final outcome was time to fusion at one year on the scanner and plain x-rays. The Oswestry score and pain at the harvesting site as well as side effects were also noted.

Results: The cohort included 27 patients. Three were excluded from the analysis, leaving 24 patients assessed at one year. The demographic data were comparable for the two groups regarding mean age (64 years versus 69 years for the OP-1 group). At one year, ten radiographically certain fusions were noted in the control group and eight in the OP-1 group. Two nonunions and one doubtful fusion were noted in the control group compared with three doubtful fusions in the OP-1 group. The mean Oswestry score was comparable in the two groups. The mean score in the control group improved from 49.5 to 28.5 compared with 45.9 to 29.7 in the OP-1 group. There was no secondary effect attributable to use of OP-1. There were no cases of systemic toxicity, nor heterotopic calcification or restenosis for the 11 patients in the OP-1 group.

Conclusion: A fusion rate of 73% without secondary effects attributable to OP-1 was observed in this preliminary study. This study allows the conclusion that this technique is reliable, safe and, in terms of fusion, a valid alternative to autologous iliac crest graft. The main advantage resulting from the use of OP-1 is to avoid the morbidity linked with harvesting the iliac graft.


Jérome Allain Joël Delécrin Jacques Beaurain Oman Ketani Lucie Aubourg Michel Samaan Françoise Roudot-Thoraval

Purpose of the study: Indications for disc prosthesis is generally established on the basis of the MRI findings (MODIC classification) and the discography. We considered that knowledge of the preoperative disc height is also important. We report a multicentric study of the results of lumbar arthroplasties as a function of preoperative height of the operated disc.

Material and methods: A Mobidisc prosthesis was implanted in 93 patients and followed prospectively for at least one year (mean follow-up 5 years). Disc height was compared with the height of the suprajacent disc and divided into three groups: > 66% of height (GI) i.e. a subnormal disc height (n=30), 33–66% (GII) moderate impingement (n=36), < 33% (GIII) total impingement (n=27). A MODIC signal was found for 19% in GI, 42% in GII and 40% in GIII.

Results: The lumbar VAS improved from 6.7 to 3.2 (GI), 6.2 to 2 (GII) and 6.2 to 1.5 (GIII). The radicular VAS improved from 4.8 to 3.1 (GI), 5.7 to 2.4 (GII) and 5.5 to 1.6 (GIII), respectively 69, 75 and 85.5% of the patients were satisfied or very satisfied for relief of the lumbar or radicular pain. The Oswestry score improved from 50 to 22% (GI), 49 to 20% (GII) and 46 to 12% (GIII). By MODIC, the lumbar VAS improved from 6.5 to 2.8 (MODIC 0) and from 6.6 to 2 (MODIC 1). The radicular VAS was improved from 5.5 to 2.9 (MODIC 0) and from 5.3 to 2.1 (MODIC 1). The Oswestry score was improved from 52 to 24% (MODIC 0) and from 48 to 15% (MODIC 1). Independently of MODIC, the VAS was always better for very tight discs and lower if the disc height was preserved.

Discussion: An influence of the disc height was found for all parameters studied, irrespective of the type of disc disease as described by the MODIC classification. The presence of a tight preoperative disc height appeared as the essential prognostic factor for discal prostheses. For a MODIC 0 discopathy, without loss of disc height, only 67 and 61% of the operated patients were satisfied or very satisfied with relief of lumbar and radicular pain (VAS 3.6 and 3.4) for respectively 88 and 75% of the MODIC0 discopathies with discal impingement (VAS 1.5 and 1.5). Though it should not be formally ruled out, surgery for discopathy with a preserved disc height should be examined prudently before implanting a disc prosthesis.


Benjamin Blondel Patrick Tropiano Thierry Marnay

Purpose of the study: The purpose of this work was to analysis the clinical results of lumbar disc arthroplasty as a function of the type of degenerative discopathy in patients with MODIC 1 anomalies at the MRI.

Material and methods: Sixty-five patients were included in this prospective study over a two-year period. Mean age was 43 years (range 23–59). All patients had a single level lumbar discopathy with MODIC 1 signs on the MRI. The discopathy was classed H0 for isolated degenerative disc disease, H1 for an associated disc overhang, H2 in the event of a recurrent disc hernia, and H3 if there was a post-discectomy syndrome. The clinical analysis was based on the VAS for lumbar and radicular pain and the Oswestry score noted preoperatively then at 3, 6, 12 and 24 months postoperatively.

Results: In the 12 patients classed H0, a significant decrease in the lumbar and radicular VAS was noted at 24 months, similarly for the H1 patients (n=25), the H2 patients (n=12) and the H3 patients (n=16). The Oswestry score also improved significantly in the different groups: 25/50 preoperatively to 5/50 at last follow-up in H0, 25/50 to 7/50 in H1, 27/50 to 11/50 in H2, and 31/50 to 13/50 in H3. There was a statistically significant difference between the results in H0 and H3 and between H1 and H3 (p< 0.05).

Discussion: In patients with degenerative discopathy with MODIC1 signs on the MRI, the results of disc arthroplasty are globally satisfactory with a significant clinical improvement. There are however statistically significant difference as a function of the type of discopathy. These preliminary data provide a base for reflection concerning the expected results and about information to give patients for whom a lumbar disc arthroplasty may be proposed.


Yann Philippe Charles Julia Bouchaib Erik Sauleau Jean-Paul Steib

Purpose of the study: The in situ contournage technique can be used to correct the 3D spinal deformity resulting from scoliosis; the manoeuvres enable rotational corrections, medialisation, and kyphosis and lordosis of strategic segments of the spine. A preliminary study identified a prolonged zone of thoracolumbar sagittal rectitude in thoracic, double major and lumbar scoliosis, indicating the vertebrae with the maximal rotation and the zones of hypokyphosis and hypolordosis. The purpose of the present study was to analyse the correction and sagittal balance of these segments after in situ contournage.

Material and methods: The pre- and postoperative radiographs of 54 patients (48 female, 6 male, mean age 21 years, mean follow-up 8 years) with idiopathic scoliosis (36–104) were analysed with Spineview. The types of curvatures, the levels included in the sagittal rectitude and the vertebrae with the maximal rotation were determined. The kyphosis was measured on T4-T12, T4-T8 and T9-T12. Lordosis was measured on L1-S1, T12-L2, L3-S1. Tilt on T1 and T9 and sacral slop as well as pelvic version and incidence were determined.

Results: Three characteristic configurations were analysed: thoracic curvature with sagittal rectitude T8-L1 and maximal rotation at T7-T8, double major curvatures with sagittal rectitude T9-L2 and maximal rotation at T8-T9 and L2-L3, and lumbar curvatures with sagittal rectitude T12-L4 and maximal rotation at L1-L2. After posterior instrumentation, the T4-T12 hyperkyphosis decreased on average from 24.1 to 17.4° (p=0.0001) and the T9-T12 hypokyphosis increased from 3.6 to 8.6° (p=0.0001) for the thoracic and double major curvatures. The T12-L2 hyperlordosis increased from 6.6 to 10.3° (p=0.027) and the L3-S1 lordosis decreased from 42.1 to 38.9° (p=0.463) in the lumbar and double major curvatures. Tilts, sacral slope, and pelvic version and incidence did not vary significantly.

Conclusion: The prolonged thoracolumbar sagittal rectitude exhibits three distinctive configurations. Each configuration indicates the level of maximal rotation at the superior or inferior end. It enables a decomposition of the overall thoracic kyphosis into a superior segment of hyperkyphosis and an inferior segment of hypokphosis and to identify a zone of superior lumbar hypolordosis. In situ contournage corrects the vertebral rotation, the kyphosis and the lordosis and acts on the strategic vertebrae. The rectitude can be used to better identify the zones requiring correction in order to optimise the balance between the thoracic kyphosis and the lumbar lordosis while improving vertebral rotation by traction or compression.


Romain Debarge Guillaume Demey Pierre Roussouly

Purpose of the study: Ankylosing spondylarthritis (AS) can progress to stiff thoracolumbar kyphosis which has an invalidating impact. Several publications have reported results with transpedicular osteotomies using horizontal or vertical reference lines. The purpose of our work was to report our experience with a new angle allowing the evaluation of the overall kyphosis (T1-S1) before and after correction by transpedicular osteotomy. The postoperative results were compared with the pelvic incidence (PI).

Material and methods: This was a radiographic study comparing a control group (154 asymptomatic volunteers and a group of patients with AS (n=28) who underwent posterolateral fusion associated with lumbar transpedicular osteotomy. The radiographic protocol was the same for the two groups. A large view including the entire spine was obtained (lateral and AP). We measured the classic pelvic parameters (pelvic incidence and version, sacral slope), C7 tilt and the spinosacral angle (SSA). All measured were made with computer assistance by the same operator. Twelve osteotomies were performed on L4 and 16 on L3.

Results: The PI was greater in the AS group compared with controls (61 vs 51). Seven patients have a PI < 50 (46 on average) and 21 had a PI > 50 (67 on average). For the C7 tile preoperatively, the low incidences had a low sacral slope and low pelvic version and greater global kyphosis than the high incidences (90 vs 98). In the control group, the C7 tilt and the SSA were 95.4 and 135.2 respectively. In the AS group, the C7 tilt increased from 72.6 to 83.1 (p=0.0025). The SSA increased from 96.4 to 13.3 (p=0.003).

Discussion: Pelvi with a low PI have a lower sacral slope than those with a high incidence; thus they can tolerate greater kyphosis before reaching an imbalance. For the high incidences, the pelvis has to retroverse more to obtain a low sacral slope. The minimal extension of the hips can limit this mechanism. After the osteotomy, all of the radiographic parameters were improved, but the SSA remained less than in the control group. The SSA is a good indicator of global kyphosis. Insufficient correction by unique lumbar transpedicular osteotomy explains the persistent retroversion of the pelvis postoperatively. The C7 tilt is useful to assess the improvement in the sagittal balance and the SSA give a better appreciation of the kyphosis correction per se.


Julia Bouchaib Yann Philippe Charles Erik Sauleau Jean-Paul Steib

Purpose of the study: Prolongation of the phyisiological sagittal rectitude of the thoracolumbar junction (T11-T1) is often observed in thoracic, double major and lumbar idiopathic scoliosis. The purpose of this study was to check the potential relationship between vertebral rotation, type of curvature in the frontal plane, and the observation of sagittal rectitude exceeding four vertebrae.

Material and methods: The preoperative radiographs of 54 patients (48 female, 6 male, mean age 21 years) with idiopathic scoliosis were analysed with Spineview. The type of curvature: thoracic, double major or lumbar (Lenke 1, 3 or 5) and the Cobb angles were noted. The levels included in the zone of sagittal rectitude, the thoracic kyphosis, the lumbar lordosis, the sacral slope, the pelvic incidence and version, the T1 to T9 tilts were noted on the lateral view. Vertebral rotation was analysed for all thoracic and lumbar vertebrae using the method described by Perdriolle, Nash and Moe on the anteroposterior radiographs. The axial rotation was measured on the scanner.

Results: Curvatures ranged from 36 to 104° (mean 59°). Fifty-two patients had a flat or concave back. Mean T1 tilt was 3°; it was 6° at T9. The pelvic incidence was 49°, the sacral slope 40°, the pelvic version 9°. The detailed analysis demonstrated zones of inferior thoracic hypokyphosis, and superior lumbar hypolordosis resulting in sagittal rectitude (5–7 vertebrae). The maximal vertebral rotation was situated at the superior part of the hypokyphosis or the inferior part of the hypolordosis. Three configurations were identified: 27 thoracic curvatures (Lenke 1) with cranial prolongation of the sagittal rectitude (T8-L1) and maximal rotation at T7-T8; 21 double major curvatures (Lenke 3 with cranial and caudal prolongation (T9-L2 and maximal rotation at T8-T9 and L2-L3 respectively; and 6 lumbar curvatures (Lenke 5) with caudal prolongation (T12-L4) and maximal rotation at L1-L2.

Conclusion: Thoracolumbar sagittal rectitude can be prolonged with three geometric configurations related to the type of thoracic, double major and lumbar curvatures. This zone of rectitude indicates the level of the maximal vertebral rotation at is superior or inferior extremity. It also reflects the zones of segmental hyperkyphosis and hypolordosis that need to be corrected during the surgical treatment of the scoliosis.


Anouar Bourghli Ibrahim Obeid Nicolas Aurouer Jean-Marc Vital

Purpose of the study: Revision surgery for scoliosis in adults is a technical challenge. Indications include flat back, non-union, and syndromes adjacent to the instrumentation The purpose of this work was to evaluate the pertinence of the transforaminal lumbar interbody fusion (TLIF) method for revision surgery for scoliosis in adults.

Material and methods: In our spinal surgery unit, 23 patients underwent revision surgery for thoracolumbar and lumbar scoliosis. A unique posterior approach was used. The TLIF was performed systematically at the lumbosacral level, at the non-union when it was present, and at the level of the Smith-Petersen osteotomies, as well as the levels above and below a transpedicular osteotomy. Seventeen patients presented flat back, ten non-union, five degenerative disease distal to the instrumentation and one degeneration proximal to the instrumentation. Nine patients had several indications for surgical revision. Five transpedicular osteotomies were performed in five patients.

Results: Mean follow-up was 30 months (range 18–48). On average 2.3 levels (range 1–4) were involved in the TLIF. The fusion was extended to the sacrum in 22 patients. The mean operative time was 5h50m (range 3–8 hours). Mean blood loss was 2100ml (400–4500). Postoperative lumbar lordosis (L1S1) was 53.5°, giving an improvement of 23° copared with the preoperative lordosis. Among the postoperative complications, there was one neurological complications which recovered partially at last follow-up one case of deep infection of the operative site which require partial removal of the implants and one case of recurrent non-union. There was no loss of correction in the frontal or sagittal planes with the exception of one patient who developed an infection. None of the patients in the series required complementary anterior surgery.

Conclusion: For revision surgery of scoliosis in the adult, a circumferential arthrodeis is needed to maintain the fusion. The TLIF method has the advantage of allowing intersomatic fusion via the posterior approach alone without opening the spinal canal. We consider that the TLIF technique is an alternative to two-phase procedures for revision surgery for scoliosis in adults. This method has given a good percentage of fusion in our series with little loss of correction.


Raphaël Jameson Christian Garreau de Loubresse

Purpose of the study: Management of the spinal neuroarthropathy of Charcot’s disease is recommended. Vertebral fusion should be extensive and often circumferential. The natural history of this disease, often diagnosed late, is poorly understood and the results of functional treatments not well studied. The purpose of this study was to describe the elements motivating surgical abstention and to analyse the natural course of the vertebral lesions.

Material and methods: The diagnosis of spinal neuroarthropathy was established in seven patients from 1997 to 2007. Six has paraplegia and one female patient Friedrich ataxia. The initial neurological disease was known for 18 years on average before diagnosis of the spinal neuroarthropathy. The management decision was based on patient motivation, comorbid conditions, and successive functional, clinical and imaging assessments. The patients were classed by the progression of vertebral destruction. Four patients had a non-evolving destruction, two with a stable spine and two with spinal hypermobility.

Results: The spinal stability, the absence of progression of the spinal neuroarthropathy, and in certain cases the presence of an ossification process were determining in deciding to abstain from surgery. Despite the collapse of the trunk, surgical abstention was decided for two patients basically because of the loss of spinal mobility resulting from the arthrodesis. For three other patients with progressing spinal lesions, the presence of comorbid factors (major risk of infection), patient refusal of the risk of temporary or definitive loss of function were the reasons surgery was decided against.

Discussion: According to the literature, it is assumed that abstention from surgery will invariably lead to neurological or infectious complications and even patient death. We did not observe these events in our series. The major surgery exposes to a risk of failure; certain authors have reported a complication rate of 60% and others have had 40% repeat operations. The instability induced by the spinal neuroarthropathy can be considered providential by the patient. The fact that several patients declined surgery because of the fear of worsening their handicap after arthrodesis is noteworthy. Simulation with a rigid corset was determining. The spinal neuroarthropathy does not appear to be a continuous destructive process but its natural history is not well known. Predictive elements were not identified in this study.

Conclusion: Charcot’s spinal neuroarthropathy is a challenging condition in frail patients. Disease progression, comorbid conditions, and multidisciplinary functional assessments are needed for adequate management and decision making.


Sébastien Lustig Edouard Munini Elvire Servien Guillaume Demey Tarik Ait Si Selmi Philippe Neyret

Purpose of the study: The purpose of this study was to report the results observed in a consecutive series of 54 lateral unicompartmental knee prostheses with minimum five years follow-up.

Material and methods: One hundred forty-four unicompartmental cemented HLS resurfacing prostheses were implanted with a chromium-cobalt femoral element and an all polyethylene polyethylene element. Among these consecutive implantations performed from 1998 to 2003 in accordance with indications established in 1988, 54 were lateral unicompartmental knee prostheses (37.5%) implanted in 10 men and 44 women. Mean age was 68.5 years (range 25–88). A lateral approach was used for the first six implants in this series. One patient was lost to follow-up, five died and one underwent revision for a total prosthesis. Forty-seven patients were reviewed with mean 100.9 months follow-up (64–159). Clinical data were analysed with the IKS criteria and all patients had a complete radiographic work-up before surgery and at last follow-up.

Results: In this series 96.3% of patients (n=52) were satisfied or very satisfied. Mean flexion was 133 (110–150). The mean knee score was 81.1 (25–100). Mean residual alignment was 2° valgus. A lucency was noted in 13.2% of knees, but remained stable. There was one failure requiring revision for a total prosthesis (loosening of the tibial component). The Kaplan-Meier survival was 98.1% at ten years. Three patients exhibited wear of the medial femorotibial compartment and had a medial unicompartmental implant. The overall survival (rein-tervention irrespective of reason) was 91.1%.

Discussion: Outcomes were very satisfactory, globally similar to recent series in the literature. Reliable sustainable outcomes with lateral unicompartmental implants have led us to widen our indications (moderate overweight, younger patients).


Jean Brilhault R. Dana Carpenter Sharmila Majumdar Micheal D. Ries

Purpose of the study: Kinetic studies of total knee arthroplasty (TKA) in vivo have provided divergent data but have agreed on one point: knee kinetics is abnormal after TKA. Restitution of a normal kinetics is thus the goal to reach to improve functional outcome after TKA. The Journey® TKA is specifically designed to induce automatic medial rotation of the tibia during flexion. This would align the extensor system during flexion and would reduce mediolateral shear forces applied to the patellofemoral joint. Fluoroscopic dynamic studies have been conducted in vivo to confirm the reality of the femorotibal kinematics but to date there has been no study of the patellofemoral kinematics. Magnetic resonance imaging (MRI) is the gold standard for exploring the knee. The important artefacts caused by metal implants made of chromium-cobalt alloys make it difficult or impossible to interpret the images in patients with TKA. Oxinium® implants are weakly ferromagnetic, allowing the development of a specific MRI sequence which can be used to explore a TKA.

Material and methods: We used this technique in vivo for a 3D exploration of the patellofemoral kinematics of six Jouney® TKA in comparison with five Genesis II® TKA with preservation of the posterior cruciate ligament and with 13 normal knees. We analysed: patellofemoral surface area of contact, patellar translation and shift during weight-bearing flexion.

Results: The results showed that the patellofemoral kinematics of the Journey® TKA are close to that observed in normal knees and that the patellofemoral pressures of the posterior cruciate ligament TKA are significantly higher than with the Journey® TKA.

Discussion: These findings confirm our initial hypothesis and allow hop for better functional outcome and reduced wear of the patellar implant with the Journey® TKA.


Numa Mercier Dominique Saragaglia

Purpose of the study: The purpose of this work was to analyse the long-term results obtained with 43 medial Oxford unicompartmental prostheses implanted from 1988 to 1994 for varus deviation of the knee.

Material and methods: Initially, the series included 56 patients (59 prostheses), but data were incomplete for nine patients who had died and five who were lost to follow-up. The analysis thus included 40 patients (74%): 16 were living at the time of this review (40%), 14 had died (35%) and ten had a total knee arthroplasty after failure of the Oxford prosthesis (25%). Mean age at initial surgery was 68.83±7.54 years (range 47–86). There were 13 surgical revisions: four for loosening, three for deterioration of the lateral compartment of the knee, two for repeated meniscal dislocation, two for rupture of the femoral implant and one repeated revision for impingement between the meniscal element and the femoral condyle. For ten knees, we replaced the implant with a total knee arthroplasty and in three others, we changed the meniscal piece.

Results: One year after the initial operation, the overall IKS score was 189.67±14.43 points (115–200), i.e. 93% good and very good outcomes. Regarding the initial radiographic results, overall varus of the lower limb had improved from 171.31±0.46 (161–180) preoperatively to 178±3.21 (170–186) postoperatively. Sixty-three percent of the patients had normal alignment or slight undercorrection (0–4), 19% had a greater undercorrection (5–9), 2% an excessive undercorrection (10), and 16% an over correction (181–186). At review, mean follow-up was 14.8±1.16 years (13–17) and mean patient age was 82 years (n=16). The mean overall IKS was 145.52±39.90 points. Sixty-nine percent of the patients were satisfied or very satisfied with the prosthesis. The prosthesis survival was 93% at one year, 90.5% at five years, 74.7% at ten years and 70.1% at fifteen years.

Discussion: Globally, the unicompartmental Oxford prosthesis has not provided in our hands the results we expected. Certain failures could undoubtedly have been avoided and should be included in the learning curve. Nevertheless, this prosthesis is certainly difficult to insert and carries a non-negligible risk of undercorrection, especially when the deviation is overcorrectible and care is taken to avoid dislocation of the meniscal element.


Julien Chouteau Jean Luc Lerat Rodolph Testa Michel Henri Fessy Scott A Banks Bernard Moyen

Purpose of the study: The purpose of this study was to use weight-bearing radiographies to study the mobility of the polyethylene insert in relation to the femoral and tibial components of a total knee arthroplasty (TKA) with preservation of the posterior cruciate ligament and a mobile plateau with rotation and anterioposterior translation (INNEX® Anterior-Posterior Glide, Zimmer).

Material and methods: A 3D kinematic study of the femoral and tibial component and the mobile insert was conducted on a series of 51 first-intention TKA using a computer-assisted matching system between 3D prosthetic models and the radiographic silhouette of the implants.

Results: At mean 23 months postoperatively, the poly-ethylene tibial insert exhibited an increase in its internal rotation during flexion. This rotation, knee extended, was limited to rotation between the insert and the tibial base. With increased flexion, there was an increase in the value and the portion of rotation involving the femoral component in relation with the mobile tibial insert.

Discussion: The degree of insert mobility has varied depending on the report. Certain authors have reported relatively limited mobility because of a minimally congruent superior surface allowing anteroposterior and mediolateral translation as the femur glided over the insert. Others report mobility of the mobile plateau in relation to the tibial base and minimal rotation of the femoral component. Rotation of the polyethylene insert in TKAs with a mobile plateau appears to be quite variable. With the LCS AP Glide prosthesis, anteroposterior translation of the mobile plateau was measured at a mean 5.6 mm (1–1.125 mm). Paradoxical anterior translation, rather than posterior translation, of the mobile plateau with flexion has been reported in a few patients.

Conclusion: The mobile plateau has exhibited progressive increase in internal rotation with flexion. We have concluded that the major part of the mobility occurs between the mobile plateau and the tibial base. However, with flexion, the femoral component increased its mobility over the plateau. During flexion, anteroposterior translation occurred between the femoral piece and the tibial insert, and between the tibial insert and the tibial base, but the direction of the translation of the mobile tibial insert appeared to be unpredictable with the non-constrained prosthesis used for this study.


Franck Dujardin

Purpose of the study: Prior assessment of haemorrhagic risk appears to be an essential element in orthopaedic surgery, particularly for lower limb procedures. This assessment is necessary for information delivery to the patient, for elaborating a transfusion strategy, and to choose between different therapeutic options. Despite this potential interest, data which could be used to validate this hypothesis and define and quantify what is called “haemorrhagic risk” are scarce in the literature. In order to furnish a preliminary element for reflection on this topic, a sample of 450 orthopaedic surgeons and 50 anaesthetists who perform routine arthropathy procedures for the lower limb were questioned.

Material and methods: This was an Internet questionnaire with 13 questions. Five hundred practitioners were surveyed in five western countries (France, Germany, United Kingdom, Spain, United States), 100 in each country.

Results: Globally, 90% of the practitioners considered it “important” or “very important” to evaluate the haemorrhagic risk. This percentage varied from 83% to 98% depending on the country. The main haemorrhagic complication was considered to be operative site bleeding, intra- or postoperatively, for 95% of the practitioners (89% to 98%) after hip or knee arthroplasty. The possible consequences of this haemorrhage were classified according to their gravity. Vital risk was classified N1, but not systematically or unanimously, since, for example, 75% of the French practitioners did not place vital risk in this category. Three other criteria of gravity of operative bleeding were reported, but with no clear hierarchy:

requirement for a revision of the operative site;

volume of blood loss considered important because of a drop in the haemoglobin to 4 – 6.5 g/dl, or transfusion of 2.4 – 3 packed cell units;

complications related to the haematoma, difficulties for rehabilitation or longer hospital stay.

Discussion: This survey showed that evaluation of haemorrhagic risk is considered to be an important element in orthopaedic practice, particularly operative site bleeding. The main elements constituting signs of gravity were: vital risk, revision, a threshold of blood loss, and constitution of a haematoma.


Jean-Michel Wattier Vincent Tiffreau Camille Levisse Julia Salleron François Gougeon Gilles Lebuffe

Purpose of the study: The favourable outcome with knee arthroplasty can be compromised by persistent unexplained pain. Postoperative pain accounts for about 30% of the complaints of chronic pain present in 25% of the general population and would be to a large extent of neuropathic origin (DCN). The purpose of this work was to evaluate pain before and after knee arthroplasty in terms of intensity and clinical expression.

Material and methods: A prospective monocentric epidemiology study was conducted to validate self-administrated questionnaires which, over a six month period, were completed by knee arthroplasty patients. A numerical scale (Nu) from 0 to 10, a 7-item questionnaire screening for neuropathic pain (burns, painful cold, electrical discharge, tingling, pins and needles, numbness, itching) scored 0 or 1 and positive if the score is ≥3 (DN4), an abridged qualitative pain questionnaire (QDSA) divided into a sensorial score (QDSAs) and an affective score (QDSAa), and a scale evaluating anxiety and depression (HAD) were recorded preoperatively, (T0), at 3rd postoperative day (PO), 1st (M1), 3rd (M2) and 6th (M6) postoperative month. Outcome was expressed as mean±SD or median and range.

Results: Eight men and 39 women, mean age 66.6±10.7 years were included. These patients. Fourteen of 47 (25.9%) had DCN postoperatively (2 DN4 successively ≥3). The “tingles” item for postoperative DN4 was significantly predictive of DCN (specificity 88.9%, sensitivity 83.3%). Preoperatively, the median intensity of pain was 6 (5–10) and was significantly higher in patients with DCN compared with those without DCN at M1 (4 [1–8] vs 3 [0–7]) and M3 (4 [1–8] vs 2 [0–6]) (p < 0,009) including 3/14 patients with Nu > 7 at M3. At M6, 12.7 % (n = 6/47) patients still had DN4 ≥3. The QDSAs score was higher in patients with DCN at M1 (11.8±4.4 vs 4.8±4.5; p < 0.001) and M3 (10.2±6 vs 3.5±3.2; p < 0.001). There was no significant difference between the QDSAa scores and the HAD.

Conclusion: The persistence of unusually intense pain after knee arthroplasty would suggest the pain could result from a neuropathological source which would require specific treatment because of the general insensitivity to analgesics.


Hervé Hourlier Bernard Liné Peter Fennema Marc Blaysat Michel De Lestang

Purpose of the study: The risk of homologous blood transfusion for primary total knee arthroplasty (TKA) varies between centres from 4 to 72%. Measurement of mean blood loss for patients undergoing primary total hip or knee arthroplasty led us to adopt a global blood-sparing protocol.

Material and methods: This was a prospective observational study involving 90 TKA (TC-SB) implanted by one surgeon in 56 women and 33 men, mean age 74 years, ASA 3 for 29%, mean BMI=31. Programmed autologous transfusion and blood recovery were not applied. Alpha epoeitine (EPO was administered in the preoperative period in accordance with the predicted serum haemoglobin at discharge. Tranexamic acid (TA) was injected intravenously during the operation.

Results: The mean operative time was 63 minutes, mean tourniquet time 51 minutes. During the perioperatively period, the mean 7-day blood loss was 566±254 ml red cells and 1560±643 total blood. Mean serum haemoglobin at discharge was 1.0 g/dl. Fourteen percent of patients had a postoperative serum haemoglobin less than 10 g/dl (lowest level 8.4 g/dl). One patient had a transfusion; this was a man in his nineties who was operated on without a tourniquet and without TA because of a poor arterial system. Nearly 86% of patients received TA with a significant (p< 0.05) decrease in bleeding compared with those who did not receive TA (365 ml total blood). EPO was delivered for 22% of patients (2.8 injections on average) to reached 14.2 g/dl the day before the operation.

Discussion: This overall strategy for blood sparing enabled us to reduce the risk of transfusion and limit costs. In this series, the prescription of EPO was not targeted to reach a set level preoperatively but was based on the predicted serum haemoglobin level at discharge. Thus seven patients with a preoperative haematocrit below 39 did not receive EPO. None of these patients were transfused. Their discharge haemoglobin was between 10.7 and 12.4g/dl. Use of TA should be included in the calculation of the predicted discharge haemoglobin level in order to better determine candidates for EPO injections.


Jean-Michel Laffosse Anna Potapov Michel Malo Martin Lavigne Michel Fallaha Julien Girard Pascal-André Vendittoli

Purpose of the study: A medial incision for implantation of a total knee arthroplasty (TKA) offers an excellent surgical exposure while minimising the length of the skin opening. This incision however implies section of the proximal portion of the infrapatellar branch of the medial saphenous nerve, potentially associated with lateral hypoesthesia and formation of a neuroma (painful scar). We hypothesised that an anterolateral skin incision would produce less hypoesthesia and postoperative discomfort.

Material and methods: We conducted a prospective randomised study to compare the degree of hypoesthesia after a medial or lateral skin incision for the implantation of a TKA. Fifty-knees in 43 patients, mean age 65.9±8.4 years were included; 26 knees for the lateral incision and 24 for the medial. All patients had the same type of implant. Clinical results were assessed with WOMAC, KOOS and SF36. Semme-Weinstein monofilaments were applied to measure sensitivity at 13 characteristic points. Patients were assessed at six weeks and six months. The zone of hypoesthesia was delimited and photographed for measurement with Mesurim Pro9®. Satisfaction with the surgery and the scar was noted. Data were processed with Statview®; p< 0.05 was considered significant.

Results: The two groups were comparable preoperatively regarding age, gender, body weight, height, body mass index, body surface area, aetiology, and clinical score. Operative time, blood loss, and number of complications were comparable. The functional outcomes (WOMAC, KOOS, SF36) were comparable at six weeks and six months. Active flexion was significantly greater at six months in the lateral incision group (p=0.03). The zone of hypoesthesia was significantly smaller in the lateral incision group at six weeks (p< 0.01) and at six months (p< 0.01), as were the number of points not perceived on the filament test (p< 0.01 in both cases) while the length of the incision was comparable (p> 0.05). This was associated subjectively, with less loss of sensitivity and less anterior pain reported by the patient at six months.

Discussion: Lateral and medial incisions enable comparable functional outcomes. The lateral incision produces less hypoesthesia and less anterior pain. This improves the immediate postoperative period and facilitates rehabilitation as is shown by the gain in flexion at six months.


Franck Accadbled Damien Louis Matthew Rackham Peter Cundy Jérome Sales de Gauzy

Purpose of the study: Increasing the number of times the operating room doors open increases the number of airborne bacteria and consequently the rate of postoperative infections with sometimes disastrous results, particularly for prosthesis surgery.

Material and methods: An observer counted the number of times the door to the operating room were opened during orthopaedic operations. The study was conducted in a teaching hospital (hospital A) during scoliosis surgery then repeated for a similar operation after posting dissuasive signs and delivery of information to the personnel concerning the risk of contaminating the patient. A study was then conducted for total hip arthroplasty (THA) in another teaching hospital (hospital B) and in a private clinic (hospital C). The same protocol as used in South Australia was applied for these studies.

Results: The mean rate of door opening in hospital A was 0.52/min. This rate was 0.45/min (13.5% less) in the same hospital A after posting dissuasive signs on the doors and providing information to the personnel. In hospital B, the rate was 0.67/min. In hospital C, the rate was 0.42/min (i.e. 37% less). In Australia, the mean rate was 1/min in hospital A before sign posting and information delivery and 0.65 (−35%) after. In hospital B, the rate was 0.87/min and in hospital C 0.47/min (i.e. 46% less).

Discussion: Nearly 50 years ago Sir John Charnley demonstrated that airborne contamination must be controlled in prosthetic orthopaedic surgery. In France airborne contamination is regulated by a series of standards (NF EN ISO 14644 established in 1999) and partially controlled during the design phase of operating rooms with the installation of laminar flow ventilation. Door opening, and particularly swinging doors, causes turbulent airflow increasing bacterial contamination.

Conclusion: Circulation in the operating room should be limited to necessary organisation (prior transport of instruments and consumables, fluoroscope, nursing staff turnover, etc.) and by information and education of all participants. The presence of observers is inevitable in the operating rooms of teaching hospitals. Their entrance and exit should however be limited and their movement within the room controlled. It is also recommended to use cell phones.


Frédéric Jacquot Mokrane Ait Mokhtar Alain Sautet Jean-Marc Féron

Purpose of the study: The goal of palliative surgical treatment of vertebral metastases is to avoid, stabilise, or improve neurological disorders and to relieve pain. We propose early treatment for fixation of threatening lesions and extensive release without resection for programmed surgery outside the emergency context.

Material and methods: From 2001 to 2005, eighty patients underwent scheduled surgery for threatening or symptomatic lesions. Mean age was 59 years (range 32–82). The primary tumour was: breast (n=35), lung (n=19), kidney (n=8), uterus (n=1), prostate (n=2), ENT (n=3), gastrointestinal (n=5), haematology (n=7). Sixty-six patients presented Frankel B to D neurological involvement. The Tokuhashi score was 8 on average (range 5–9) and the Karnofsky index 57% (range 30–70). Sixty-four patients had visceral metastases. On average 7 levels were instrumented (range 4 to 8). The procedure included laminectomy in all cases.

Results: Blood loss was 500 cc (300–2700) and operative time 110″ (65–110). Fifty-nine patients recovered one or more Frankel grade. Six patients (7%) developed a postoperative infection. The actuarial survival at one year was 78%; 95% for patients free of motor neurological involvement and 65% for the others. This difference was significant.

Discussion: Spinal metastases should be detected and treated before emergency care is required. At the present time this treatment is well programmed. Fixation without tumour resection enables prolonged survival and allows time for other treatments in a pluridisciplinary management scheme. Several therapeutic options are possible but converge towards improved quality of life.

Conclusion: Posterior tumour resection is not useful for palliative surgical management of vertebral metastases. We propose an active approach using a simple well-defined surgical procedure without waiting for development of a neurological emergency.


Saidou Diallo Odile Bajolet Nicolas Fontanin Vincent Girard Alain Harisboure Emile Dehoux

Purpose of the study: Prevention of operative site infections (OSI) in orthopaedic surgery requires strict observation of validated practices during hospitalisation and in the operative theatre, review of morbidity and mortality, and surveillance of OSI. Certain intrinsic patient-related risk factors of OSI cannot be controlled without direct implication of the patient and the referring physician. Search for Staphylococcus aureus (SA) colonisation and bacteriuria should be done in the ambulatory setting, before hospitalisation. The purpose of this work was to evaluate the feasibility of a search for SA in the nasal swabs and urine samples in patients scheduled for prosthesis surgery.

Material and methods: This was a prospective study on 335 patients who had a total hip arthroplasty (THA) or a total knee arthroplasty (TKA) from January 1, 2007 to December 31, 2008. Bacteriological tests were performed before hospitalisation. Before hospitalisation, the patient and the primary care physician were give information on the proper procedure for chemical decontamination. The results of these laboratory tests were analysed and OSI were followed.

Results: Three hundred thirty-five patients (195 THA and 143 TKA) were included; the sex-ratio was 0.95 M/F. Sixty-one patients (18%) exhibited SA colonization, including two meticillin resistant strains. Urine samples were positive in 30/323 patients (9.3%). Three patients presented an early OSI: two infections of a revision THA and one infection of a revision TKA. Two of these patients had an SA infection, including one who was colonized and had applied the chemical decontamination protocol before hospitalization.

Discussion: By treating bacteriuria before hospitalization, deferral of the scheduled operations could be avoided. Laboratories must run two sets of tests to search for both met-S and met-R SA, which in our experience was not always the case despite written prescriptions. Implementation of chemical decontamination of the nasal passages and skin before surgery requires a well-established cooperation between the primary care physician and the hospital. The three infections recorded in this series involved revision procedures, with a context of rheumatoid polyarthritis for two patients.

Conclusion: Systematic screening for SA colonization in orthopaedic surgery remains a subject of debate, particularly concerning the cost-efficacy balance, but can be quite useful in certain situations such as revision or prosthetic surgery in immunodepressed patients.


Donatienne Joulie Caroline Loiez Laurence Legout Hervé Dezeque Bernadette Roselé Carlos Maynou Eric Beltrand Emmanuel Hue Eric Senneville Henri Migaud

Purpose of the study: Factors affecting the course of Staphylococcus aureus (SA) infected total hip arthroplasty (THA) and total knee arthroplasty (TKA) are poorly understood.

Material and methods: The microbiology laboratory database on patients hospitalised from June 2001 to June 2006 for medical and surgical treatment of an SA infected THA or TKA were reviewed. Data collected were: clinical, radiological, and biological (CRP) status known at least two years after the end of the antibiotic treatment. Success was defined as normal findings in all three domains at last follow-up and failure for any other situation.

Results: The series included 87 patients (43 male and 54 female, mean age 66.5 years, 62 THA, 35 TKA). Material was removed in 51 patients (52.6%). The infection was related to met-R SA in 14 patients (14.4%) and polymicrobial infection in 24 patients (24.7%). Mean duration of intravenous treatment was 7.3±9.4 days and total duration of antibiotic treatment was 115.472.2 d. At mean follow-up of 54.1±19.4 d, the overall success was 62/97 (63.9%). The only parameters significantly associated with failure were delay to management after first signs revealing longer infection (67.9 days vs 144.8 days) and an antibiotic therapy not adapted bacteriological results to immediately after surgery. (28.6% vs 3/28; 4.8%). In this series, met-R SA was not a risk factor of failure.

Conclusion: This work suggests that delayed surgical management and quality of antibiotic treatment for the first revision are factors affecting the prognosis of SA infected THA and TKA. These results are in favour of a multidisciplinary approach to care for these patients.


Laurent Jeunet Jean Daniel Kaiser Lydiane Bellidenty Francis Berthier Isabelle Patry Xavier Bertrand Joel Leroy Catherine Chirouze Thierry Henon Thomas Meresse Sylvie Grandperret Johann Malpica Patrick Garbuio

Purpose of the study: Management of bone and joint infections is a recognised public health concern recently labellised by the establishment of Reference Centres and associated Reference Centres. Among other objectives, these Centres are designed to develop pluridisciplinary expertise in the form of recommended clinical practices (French Health Ministry directive DHOS, May 2008).

Material and methods: In response to this tender, a weekly pluridisciplinary meeting was instituted in March 2008 with an orthopaedic surgeon, an infectious disease specialist, an anaesthetist, a pharmacist, microbiologists, a rheumatologist and a diabetologist. The activity and impact on antibiotic consumption in the functional unit of septic surgery was evaluated over a one-year period.

Results: From March 2008 to March 200, 35 pluridisciplinary meetings were held and analysed 243 files concerning 133 patients. This consensual approach led to a decrease in the antibiotic consumption in the functional unit. This consumption was 1222 DDJ/1000 days hospitalisation during the last semester of 2007 and 1069 DDJ/1000 days during the last semester of 2008 (p=0.005). During this same period, the activity in the unit increased from 37 patients with infected material (CIM 10 T 84) in 200 to 58 in 2008 and from 27 patients with septic arthritis (codeM00) to 42 in 2008. Similarly the number of indexed pathological conditions in this unit increased from 447 to 548 in 2008 with a fall in the mean duration of the hospital stay from 11 days in 2007 to 9.6 in 2008. The improvements provided by the process of intraoperative sampling provided bacteriological documents in 85% of cases. The analysis of antibiotics prescribed in the functional unit showed a decline in the consumption of antibiotics with week or unknown distribution in bone (amoxicillin + clavulanic acid: −13%; pristinamycin: −72%) and an increase in the prescription (before adaptation to documented bacteriological results) of the association cefotaxime+fosfomycin (5-fole increase in one year).

Discussion: This study clearly shows how important regular pluridisciplinary discussion is needed to optimise the management of bone and joint infections and that this approach improves the antibiotic prescription and shortens the hospital stay.

Conclusion: This experience proves the pertinence of the Reference Centres and the associated Reference Centres, both economically and medically.


Fabrice Thévenin David Biau Jean-Luc Drapé Antoine Babinet Philippe Anract Frédérique Larousserie Antoine Feydy

Purpose of the study: The objective was to assess the diagnostic yield of angioscanner evaluation of arterial invasion of limb tumours before surgery.

Material and methods: This was a prospective study conducted from January 2005 to May 2008 designed to assess 55 arterial segments and limb or pelvic tumours on the preoperative angioscan. Screen displays of the radiographic images were reread conjointly but radiologists using vascular analysis software. Contact of a large vessel with the tumour was classified as follows: fatty line, contact less than 90° of the vessel circumference, contact less than 180°, contact ≥ 180°. Intraoperative vessel-tumour contact was classified as follows: cleavable, non-dissectible. Agreement between the angioscan and the operative findings was analysed.

Results: Forty-five arteries were cleavable and ten non-dissectible. All arteries that were separated from the tumour by a fatty plane or were in contact over less than 90° of the circumference of the vessel were cleavable at surgery (n=37/37). The sensitivity, specificity and diagnostic accuracy and the rate of positive scan for probable arterial contact > 180° were 90, 93, 93 and 13.5% respectively.

Conclusion: The angioscanner provides a satisfactory means for predicting vascular invasion of limb and pelvic tumours and contributes pertinently to the pre-operative work-up.


Alain Meyer Bernard Toméno Frédéric Sailhan Philippe Anract

Purpose of the study: We present our cases of hemangiopericytomas treated surgically in our department of orthopaedic oncology. The purpose of this work was to study this vascular tumour rarely reported in the orthopaedic surgery in order to establish epidemiological, management, and prognostic elements.

Material and methods: This was a retrospective descriptive study of patients seen since 1995 with benign (n=4) or malignant (n=16) hemangiopericytoma. The large majority were FNCLCC grade 2. Mean follow-up was ten years. Course before diagnosis was longer for benign tumours (14 years) than malignant tumours (0.9 years). Tumour localization was the lower limb (55%), the upper limb (3%) (constantly involving the scapular girdle) and isolated tumours (sternum, dorsal tumours). Two patients presented metastasis at diagnosis. A biopsy was obtained in all cases.

Results: The sample contained soft haemorrhagic tissue in all cases. The typical histology was a proliferating vascular architecture with either a fibrous or muscular component. Immunohistochemistry studies revealed positive labelling for vimentin and CD99. The diagnosis of malignancy was particularly difficult, often because of the poor knowledge of pericyte differentiation. For the benign tumour, treatment consisted in resection followed by clinical and radiographic surveillance every six months. No recurrence was observed at more than five years follow-up. For the malignant tumours, all patients were given neoadjuvant chemotherapy followed by wide resection. Adjuvant chemotherapy, determined according to the resection margins and presence of not of metastasis, was instituted for 60% of patients and associated with radiotherapy for two. The total-remission survival for malignant tumours was 60% at five years. Local recurrence was noted in 18% of patients and development of metastasis in 10%. Mortality was 20%.

Discussion: The histology diagnosis was not straightforward, particularly for confirming the benign nature of the tumour; search for specific markers is needed for routine diagnosis.

Conclusion: The results obtained in this series provide valuable information for the diagnosis of sarcoma, particularly concerning the controversial issue of the aggressiveness of malignant tumours.


Pierre-Louis Docquier Laurent Paul Olivier Cartiaux Xavier Banse Christian Delloye

Purpose of the study: Resection of sarcomas from the pelvis is particularly difficult because of the risk of injury to the vascular and neurological structures and the complex helicoidal anatomy of the iliac bone. Salvage of the lower limb is preferable but raises the risk of an insufficient resection margin. Imaging procedures (CT scan, magnetic resonance) allow preoperative planning but intraoperative landmarks are not always easy to recognise. Navigation might be highly useful for this type of surgery.

Material and methods: Two patients with a sarcoma of the pelvis (chondrosarcoma and synovial sarcoma) underwent tumour resection using a navigation system. For the second patient, the cut for the bone graft was also navigated enabling reconstruction with a perfectly adjusted graft. The tumour was delimited on each magnetic resonance slice to produce a 3D reconstruction image. This volume was co-recorded on the scanner. The scan with the tumour limits was fed into the navigation machine. Resection planes were chosen taking into account the surgical approach, the type of reconstruction desired, and the healthy margin accepted. These planes were then transposed onto the allograft scan to enable an exactly adapted cut. Plaster prototypes were modelled from the scan of the patient’s pelvis and the allograft scan. The tumour resection and the allograft procedures were repeated on the prototypes using the navigation system.

Results: The navigation system was used successfully as planned preoperatively. The planes of the cuts were as planned. The healthy margin was sufficient in all cases and confirmed at the pathology exam.

Discussion: Navigation enables exact localisation in relation to the tumour throughout the operation. A healthy margin of one centimetre or more can be achieved safely. The allograft cut can be made by another surgeon simultaneously with the tumour resection, saving time. The allograft-host contact surface is improved giving a good congruency with the graft.

Conclusion: Navigation is a very useful tool for resection of pelvic tumours and their reconstruction.


Olivier Barbier Philippe Anract Etienne Pluot Frédérique Larouserie Antoine Babinet Bernard Tomeno

Purpose of the study: Extra-abdominal desmoids tumours are benign tumours generally managed by more or less wide surgical resection. This surgery can be mutilating and carries a risk of recurrence to the order of 50% according to several authors.

Material and methods: We followed a series of 26 patients from 1989 to 2009 with non-operated extra-abdominal desmoids tumours. Our objective was to study the clinical, radiographic and pathological course of these tumours and identify prognostic factors. For 11 patients, no medical or surgical treatment was delivered beyond the diagnostic biopsy; for 15, the tumour recurred after surgery and no other adjuvant treatment was given.

Results: Twenty-four tumours stabilised at 13.2 months on average for primary tumours and 20.9 for recurrent tumours. Thus en general, the tumour progression was less than 3 years. In all cases, once the tumour stopped progressing, it did not progress again. One primary tumour regressed spontaneously and one recurrence continued to progress at last follow-up of 23 months. Surgery was not required for any of the patients, excepting biopsy procedures to confirm diagnosis. MRI was the exploration of choice for follow-up.

Discussion: This series, which is the largest devoted to followed extra-abdominal desmoid fibromas, confirms recent data in the literature. A wait-and-see attitude should always be discussed with this type of tumour.


Jean-Charles Aurégan Frédéric Sailhan David Biau Mathieu Karoubi Valérie Dumaine Antoine Babinet Philippe Anract

Purpose of the study: Secondary chondrosarcoma is rare (1% of malignant bone tumours). Most cases develop from solitary exostosis or concern an exostosis disease. Localisations predominate in the girdles. Management is difficult and no consensus has been reached. The purpose of this study was to present a series of 25 secondary chondrosarcomas in order to improve diagnostic and therapeutic management.

Material and methods: This was a retrospective analysis of 25 cases of secondary chondrosarcoma (10 on solitary exostosis and 15 on exostosis disease) treated by one surgical team from 1970 to 2008. The epidemiological features, clinical signs, radiographic findings, type of treatment and outcome at last follow-up were analysed for the two groups.

Results: Patients with secondary chondrosarcoma were 10 to 20 years young than those with primary chondrosarcoma. There were an equivalent number of men and women and the predominant sites involved flat bones in both groups. The radiographic signs of sarcomatous degeneration most widely observed included heterogeneous calcifications, irregular contours, and soft tissue invasion. Tumours were generally well differentiated. The rate of local recurrence after surgery was 15% at five years and 20% at ten years. Mortality was 2% at five years and 5% at ten years. Most of the deaths occurred after local recurrence. Metastases were identified in four patients after the initial resection. The rate of local recurrence was lower after wide surgical resection.

Discussion: The real objective with secondary chondrosarcoma is to ensure a regular effective follow-up of these patients with a known risk of recurrence (exostosis disease) in order to recognise early signs of sarcomatous degeneration. One of the most reliable signs is recent development of unusual pain on a known exostosis. Education of at-risk patients is crucial and should enable early screening and detection.

Conclusion: Secondary chondrosarcoma occurs 10 to 20 years earlier than primary sarcoma and generally involves the girdles. Outcome and management practices are similar to primary chondrosarcoma. The most important issue is to ensure good patient follow-up in order to enable early diagnosis in patients at risk.


Laurent Mathieu Christophe Oberlin

Purpose of the study: Neurolysis is required for the treatment of non-regressive posttraumatic or spontaneous palsy of the anterior interosseous nerve. This technique is difficult because of the anatomic variability of the nerve and the neighbouring structures. The purpose of this study was to determine the imperative elements for neurolysis by analysing the anatomic relations of the anterior interosseous nerve and identifying the potentially compressive musculo-aponeurotic and vascular structures.

Material and methods: Twelve fresh anatomic specimens were dissected unilateral; the subjects (six male, six female) were aged 82.6 years on average at death. Emergences of the anterior interosseous nerve and its division branches were studied. The relations with the following structures and their anatomic variations were analysed: the lacertus fibrosus, the fibrous arcades of the pronator teres, and the flexor digitorum superficialis, the accessory head (if present) of the flexor pollicis longus (Gantzer muscle) and the vascular structures in close contact with the nerve. The topographic landmarks were noted in relation to the bi-epicondylar line.

Results: Emergence of the anterior interosseous nerve was situated, on average 54.5 mm below the bi-epicondylar line, on the posterior (n=9) or ulnar (n=3) aspect of the median nerve. The relative situations of its division branches were variable. A fibrous arcade was found between the lacertus fibrosus and the pronator teres in two specimens. Nine specimens had two arcades at the pronator teres and the flexor digitalis superficialis, but three specimens only had one. The presence of an accessory head within the flexor digitalis superficialis was a configuration with risk of nerve compression. The Gantzer muscle was present in six specimens and crossed the nerve superficially. Two types of potentially compressive vascular arcades were found in eight specimens.

Discussion: Sites of compression of the anterior interosseous nerve were found a various positions and in variable numbers in the different anatomic specimens. The presence of several sites of compression in the same individual could explain why the electromyogram fails to identify the level of the nerve compression in certain cases, leading to the standardised neurolysis technique recalled here.

Conclusion: This study demonstrates that several sites of potential compression of the anterior interosseous nerve can coexist in the same patient. The surgeon should be perfectly aware of these “at risk” sites when performing neurolysis.


François-Laurent Marty Philippe Rosset Gilles Faizon Jacky Laulan

Purpose of the study: Available epidemiological data on hand and wrist tumours are scarce and sometimes discordant. In our unit, these tumours are managed conjointly by hand surgeons and tumour specialists. We conducted an epidemiological study of 624 tumours treated from 1980 to 2008.

Material and methods: The recruitment used three methods: diagnostic coding in the database, analysis of discharge letters, study of tumour registries. All hand and wrist tumours treated surgically in our unit were included retrospectively. Exclusion criteria were: patients aged less than 15 years and/or managed in the paediatric surgery unit; poorly identified cases; recurrences.

Results: The study population included 624 tumours (375 female and 249 male). Mean age was 48 years (range 16–94). Eight tumours were malignant: 4 skin, 3 soft tissue, 1 bone metastasis of a primary renal tumour. Soft tissue tumour concerned 525 patients (84.1% of the study population). Respectively, 71 tumours concerned bone and 28 skin. There were 221 synovial cysts. The bone tumours exhibited a harmonious distribution for age and gender with a peak from 35 to 50 years and a sex ratio of 1/1. There were 43 chondromas found at all ages, mainly in long bones.

Discussion: Our series is the third largest reported. A review of the literature identified the eight largest studies available. For 6452 tumours, 81.7% concerned soft tissues, 13% skin, 4.7% bone tissue. These lesions occurred at all ages with female predominance (60%). Malignant tumours were found in 4.4% of the cases. Exclusion of the paediatric cases and the retrospective nature of the data collection were the main biases of this work.

Conclusion: Data on 624 hand and wrist tumours were in agreement with published work. Tumours involved mainly soft tissues. Synovial cysts predominated. Chondromas accounted for 70% of the bone tumours. Malignant tumours were rare (2.9%). For suspect cases, we recommend referral to a specialised centre for the management of malignant tumours of the hand. A pluridisciplinary analysis is indicated to adapt the diagnostic and therapeutic strategy.


Bertrand Coulet Bertrand Coulet David Lumens Jacques Teissier Charles Fattal Yves Allieu Michel Chammas

Purpose of the study: Construction of a key grip is the final objective of programmed functional surgery of the upper limb in the tetraplegic. Three phases are necessary: activation of the grip, simplification of the poly-articular chain, and positioning the thumb column. For this operative phase, two techniques can be used, either fusion of the articulation with a trapezometacarpal arthrodesis (TMA) or a soft tissue procedure (tenodesis of the abductor pollicis longus). Our study compared analytically these two techniques, considering grip force and stability and the quality of the key grip opening.

Material and methods: This was a retrospective study of 38 key grips with a mean follow-up of 7.4 years in a population of tetraplegic patients (groups 1 – 5 in the International Classification of Giens. Seventeen active key grips including 11 with TMA and 21 passive key grips including 16 without TMA with regulation of the thumb position by soft tissue procedures. The active and passive grips according to the procedures were comparable statistically for their median ASIA motor scores.

Results: The force of the active key grips with TMA (mean 2.7± 1.3 kg) was significantly greater than that obtained after tenodesis (1.3±0.7 kg) (p=0.05). For passive key grips, the difference was not significant, 1.1±0.6 kg with TMA versus 1.0±0.9 kg without. Twenty-three percent of the grips were unstable after TMA versus 24% after tenodesis. Regarding grip opening, the mean distance between the pulp of the thumb and the index was 3.7 cm for active key grips after TMA by tenodesis effect and 5.4 cm for holding large objects while without TMA these values were 3.2 cm and 6.4 cm respectively. For passive grips, these same values were 2.2 and 3.4 cm after TMA versus 2.4 and 6.8 after tenodesis.

Discussion: For the active key grip, TMA enables a stronger grip but with loss of opening distance for large objects. Conversely, for the passive key grip, TMA does not enable a stronger grip but significantly limits passive opening. Globally TMA yields a more constant result. In patients with a limited motor potential, it is important to favour the creation of two different grips.


Yves Allieu Guillaume Saint-yves Thierry Judet Philippe Denormandie

Purpose of the study: From November 2001 to January 2008, among 110 patients who underwent surgery for spastic hands due to a central neurological disorder, the management involved surgical treatment of long finger intrinsic and extrinsic deformities in 57 brain injury adults.

Material and methods: At least one procedure for the intrinsics and one for the extrinsics was performed during the same operative. Twelve patients had bilateral operations. The goal of the surgery and the treatment was established during multidisciplinary consultations with rehabilitation physicians, neurologists, surgeons and anaesthesists after a minute physical examination with selective neuromuscular blocks to differentiate muscle spasicity and tendon retraction from extrinsic and intrinsic disorders. The objective was established in the form of a contract with the patient and the family: hygiene and analgesia (47 patients), aesthetic aspect (15 patients, and/or function (21 patients.) For the spasticity and/or retraction of the exrinsics, we used 23 transfers of the FCP to the FCS, 6 Z lengthening of the FCP and the FCS, 14 intramuscular lengthening of the FCP and 11 of the FCS, 10 Page interventions, 10 selecive muscle disinsertions from the epitrochlears and one FCS tenotomy. Concerning the spasticity and/ol retraction of the intrinsic, we performed 4 neurotomies of the deep motor branch of the ulnar nerve, 48 interosseous tenotomise, 6 proximal disinsertions with mobilisation of the interosseous, 18 tenotomies of the 5th adductor, and 29 distal tenotomise of the extensor system.

Results: Outcome was good for 60 of the 69 operated hands (achievement of contract: function 18, aesthetic 14, hygiene 44). Seven hands required revision with a good final result for six of them. One patient developed reflex dystrophy.

Discussion: In adults, despite the modest functional results achieved in only one-third of the patients, corrective surgery for spastic mixed extrinsic and intrinsic deformities provides an important improvement for these patients.


Olivier Delattre Caroline Bourges Sébastien Mouliade Pierre Sylvain Marcheix François Duroux Lucian Stratan Sylvie Carmes

Purpose of the study: The purpose of this study was to evaluate and compare the functional and radiographic results of these two surgical techniques using a prospective study.

Material and methods: This study involved two consecutive series of 70 patients with a posterior fracture of the distal radius. Mixed multiple pinning (MMP) consisted in the combination of two styloid pins and two infrafocal dorsal pins. The anterior plate was a locked ITS. The patients decided when it was appropriate to wear a brace postoperatively. Functional assessment used the range of motion, the Quick DASH score, and a self-evaluation of the number of days the brace was worn. Ulnar variance, sagittal and frontal inclination of the radial epiphysis were measured pre- and postoperatively at 45 days.

Results: At mean follow-up of 11.8 months (3–34), the functional outcome was comparable in the two groups but the patients with a plate fixation wore the brace less. Radiographically, there was no loss of final reduction with the plate fixation whereas with the pinning, there was a progressive loss of ulnar variance and less than 2% over-reduction. Major complications (tendon tears, nerve injury) were less frequent with pinning.

Conclusion: Globally, plate fixation enabled more rapid mobilisation of the wrist. Nevertheless this method has its drawbacks (duration of the operation, material availability, cost). In our opinion the mixed multiple pinning method is the treatment of choice for fractures free of major instability or anterior or circumferential comminution.


Chihab Taleb Mehdi Kheliouen Philippe Liverneaux

Purpose of the study: Nonunion is a common complication of carpal scaphoid fractures. Incidence is 10% of all fracture types. No one technique has proven totally superior for the treatment of grade IIa and IIb nonunion of the carpal scaphoid (Alnot classification). In this study, we evaluated the contribution of percutaneous screw fixation for the treatment of these nonunions.

Material and methods: Our series included 26 patients with grade IIa (n=14) or IIb (n=12) nonunions. Outcome was assessed according to the clinical impact of the screw fixation and globally using the Quick DASH function score for the upper limb. Bone healing was assessed radiographically.

Results: Good outcome was good in 81% of the patients (93% for grade IIa and 68% for IIb) with the screw fixation, a healing rate similar to that obtained with classical techniques.

Discussion: Percutaneous screw fixation has the advantage of a mini-invasive approach and limits the risk of iatrogenic complications. It should thus be more widely used for the management of carpal scaphoid nonunions.


Philippe Triclot

Purpose of the study: The tribologic characteristics of the metal-on-metal bearing enabled the introduction of large-diameter femoral heads on a conventional stem with the aim of improving implant stability. Our work was designed to determine whether the short-term outcomes corroborate this hypothesis and identify any specific complications.

Material and methods: This was a comparative study of two series of non-cemented total hip arthroplasties (THA) with a high-carbon content metal-on-metal bearing: 250 25 mm arthroplasties implanted from August 2001 to April 2004; 250 large-diameter arthroplasties implanted from August 2003 to December 2006. The two series were comparable regarding age, gender, BMI, aetiology, Devane and Harris scores preoperatively (r2=0.98; p< 0.001). Patients were reviewed at mean 5 years 5 months (28mm) and 3 years 1 months (large diameter).

Results: The analysis was possible for 224 implants in the 28 mm series and 242 in the large diameter series. Clinically, the Merle-d’Aubigné et Harris scores were highly comparable between the series; the activity item on the UCLA score revealed better results in the anatomic head series (6.09 versus 6.81; p< 0.0039). Regarding complications: There was one cases of implant migration in the large diameter series with preservation of the good outcome and no revision. For dislocations: anatomic head (n=1, 0.4% with revision); 28 mm head (n=7, 2.8% with four revisions). One particular case of one patient with a large diameter head presented two episodes of localised recurrent cellulitis under regular surveillance. Metal ion assays (medians): Cr.− 1.55μg/l for 28mm; 2.21μg/l for large diameter; Co. − 1.10μg/l for 28mm; 1.92μg/l for large diameter.

Discussion: Our results provide objective evidence of the improvement in the stability of the prosthesis joint and in the functional outcome, confirming the few results published to date. Conversely, while we did have less technical failures than published series, we did find significantly higher metal ion levels in the large diameter series, in contrast with prior data. The neck length being modulated with the intermediary piece, the potential corrosion might be the only cause of this difference.


Patrice Mertl Omar Boughebri Philippe Triclot Eric Havet Jean-François Lardanchet

Purpose of the study: Use of the metal-on-metal bearing has been validated in total hip arthroplasty (THA) for conventional diameters and for resurfacing but not with large-diameter implants. The purpose of our study was to establish the short-term clinical validity of large diameter implants.

Material and methods: This was a retrospective study of a consecutive series of 106 press-fit cups (Durom®) in 102 patients with minimum two years follow-up. Mean age at surgery was 66 years. Aetiologies were primary degenerative diseases (n=83), aseptic osteonecrosis (n=11), secondary degeneration (n=7), degeneration on acetabular dysplasia (n=2), rapid destructive osteoarthritis (n=1), fracture of the femoral neck (n=1) rheumatoid disease (n=1). Patients were reviewed with mean 30 months follow-up with the PMA and Harris scores. Radiographic measurements were made on semi-automatically (Imagicka®) and included the ratio of prosthesis head to native head diameter, acetabular offset, and any implant migration, gap or lucency.

Results: There were two traumatic dislocations due to falls with regressive tendonitis of the gluteus medius with no later consequence. The mean Harris score was 91.6 and the mean PMA score 17. Outcome was excellent (n=70), good (n=31), fair (n=3) and poor (n=2). The ratio showed that head diameter had been restored for 65 hips (0.95 to 1.05). There were no cases of cup migration. Acetabular offset showed a mean lateralization of 1.1 mm. For 67 immediate posterior gaps, including ten measuring > 2mm, only two had not filled at review. None of the radiographic measurements had an effect on the clinical outcome.

Discussion: These results are comparable with those published for metal-on-metal bearings with 28mm heads and press fit cups. We did not find any mechanical or medical cause explaining the persistent pain observed in our patients with fair or poor outcome. The low level of dislocation (1.8%) confirms the improved prosthetic stability compared with 28 mm heads.

Conclusion: In our opinion, these early results demonstrate a clear improvement in stability, but at the cost of possible unexplained pain. Long term clinical and radiographic surveillance is needed to validate this option in terms of implant wear and survival.


Stéphane Descamps Stéphane Boisgard Charles Henri Texier Benjamin Bouillet Jean-Paul Levai

Purpose of the study: The purpose of this work was to report the outcome at minimum ten years follow-up of cemented Muller total hip arthroplasty (THA) with a metal-on-metal bearing and a CLS cup.

Material and methods: From June 1995 to August 1997, 110 THA were implanted in 102 patients for degenerative hip disease. At last follow-up, 23 patients had died, four were lost to follow-up, and 67 were reviewed. Mean age was 56 years (29–71). BMI: 26.2 (17.9–33.6). Mean follow-up was 12 years (10–13). The same operative technique was used for all implantations: transgluteal approach, Palacos Gentamycine® cement, straight femoral stem, Muller prosthesis made of Protasul®10, with a Metasul® head and a CLS cup with a polyethylene sandwich Metasul® insert. Outcome was assessed clinically with the Merle score, radiographically searching for signs of loosening using the Harris criteria for the femoral component and the Hodgkinson criteria for the acetabular component. Migration was measured with the Nunn method for the cup and the Sutherland method for the femur. Dobbs actuarial survival was determined.

Results: Nine patients (9THA) underwent revision for acetabular migration (n=4), cup fracture by cam effect (n=1), psoas syndrome (n=2), retarded hypersensitivity (n=1), infection (n=1). At last follow-up, the clinical outcome was good or very good (n=64), fair (n=2), poor (n=1). Radiologically, for the femur: lucent lines (n=0), osteolysis (n=4), migration (n=0); for the cup: lucent line < 1mm stable and non migrating (n=3), global lucent line with migration > 5mm (radiological loosening) (n=1). No correlation between clinical and radiographic outcomes. Survival was 89.4±7.6% for revision outside infection and 92.6±6.9% for aseptic loosening.

Discussion: The failures at ten years were all acetabular, but related to various causes. Defective fixation could be related to the implant design or to the use of a hard-on-hard bearing increasing peripheral stress. Hypersensitivity and a cam effect related directly to using the metal-on-metal bearing. The psoas syndrome was not related to the type of cup.

Conclusion: Use of a metal-on-metal bearing, which theoretically improves wear, leads to other constraints in terms of fixation, technique, and context which must be taken into consideration to improve outcomes.


Martin Lavigne Marc Therrien Julie Nantel François Prince Jean-Michel Laffosse Julien Girard Pascal-André Vendittoli

Purpose of the study: The purpose of this work was to compare the subjective and functional outcomes of patients with a large diameter total hip arthroplasty (LD-THA) or hip resurfacing (HR).

Material and methods: Forty-eight persons were assessed and double blind randomised to receive either LD-THA (n=24) or HR (n=24). The clinical and radiographic assessment and gait analysis were performed preoperatively and at three, six and 12 months postoperatively. Gait analysis was performed once in a third group of healthy adults (n=14) who served as controls.

Results: The two groups were comparable preoperatively regarding demongraphic and functional characteristics. Postoperatively, the two groups with prostheses exhibited very rapid recovery with normalization of test results compared with controls within three to six months. The clinical assessment, the analysis of postural balance, gait analysis and most of the specific tests were not different between the two groups with prostheses.

Conclusion: There was no remarkable difference in subjective or objective assessments between subjects with a LD-THA or HR. This suggests that the only potential advantage of HR is the preservation of femoral bone stock. Long-term HR implant survival will determine the reality of this benefit.


Antoine Combes Julien Girard Marc Soenen Nicolas Krantz Henri Migaud

Purpose of the study: For young active patients, implantation of metal backed socket with a metal-on-metal bearing is an attractive tribological alternative when a standard prosthesis cannot be implanted. Metal ion assays have not been reported in this type of population. The purpose of this work was to present the clinical, radiographic and metal ion results.

Material and methods: Between 1998 and 2003 23 total hip arthroplasties (THA) (six primary and 17 revision) were implanted with a cemented Metasul™ bearing in a Muller inlay. Mean follow-up was 6.1 years (5–10). None of the patients was lost to follow-up. The Harris and PMA scores were noted as were signs of implant loosening or migration. Metal ions were assayed in total blood (Cr and Co) by mass spectrometry and atomic emission spectrometry (Ti).

Results: At follow-up, the mean Harris and PMA scores were significantly increased, from 62.2 to 95.2 (p = 0.01) and from 12.9 to 17.4 (p = 0.02) respectively. No revisions were required for aseptic loosening or failure of fixation. The radiographs did not reveal any signs of osteolysis or lucency. The mean levels of Cr, Co and Ti were 1.85μg/l (0.8–3.2). 1.24μg/l (0.5–1.86) and 9.62μg/l (5–18) respectively. Ti > 10μg/l was noted in six patients; Ti > 10 μg/l and Cr > 2μg/l in five patients. There was no correlation of metal ion levels with size of the implants, activity level, gender, clinical scores or cup inclination.

Discussion: The mean Co and Cr levels observed in this series were similar to those reported in the literature for standard THA (cementless press fit cups). Ti levels have only been reported in rare studies so that comparison with other series is hazardous. The Ti level observed here appeared to depend on the femoral stem resurfacing (in our series, the porous surface of the stem was coated with a Ti-6Al-7nB alloy).

Conclusion: Cementing the metal-on-metal bearing in the supporting inlay appears to be a reliable and attractive technique for this young and active population. Levels of Cr and Co in blood were the same as reported for standard implants. These levels of metal ions should be followed to confirm the long-term results.


Christophe Chevillotte Vincent Pibarot Olivier Guyen Jean-Paul Carret Jacques Bejui-Hugues

Purpose of the study: The ceramic-on-ceramic bearing for total hip arthroplasty (THA) has been widely used in Europe for many years. There have however been few publications on its long-term outcome. The purpose of this study was to examine the outcome at nine years follow-up of 100 THA implanted without cement using a ceramic-on-ceramic bearing.

Material and methods: The first 100 ceramic-on-ceramic THA implanted from November 1999 in our unit in patients aged less than 65 years were studied. The clinical assessment included the physical examination with search for complications and the Harris and Postel-Merle-d’Aubigné scores noted preoperatively and at last follow-up. The radiographic assessment was performed by two surgeons (double reading) to search for peri-prosthetic lucency, osteolysis, ossifications and implant migration. The state of the calcar was noted. The Delee-Charnley classification was used to classify the lucent lines for the acetabulum and the Gruen McNiece and Amstutz classification for the femur.

Results: Among the 100 THA, 20 patients were lost to follow-up. The Harris score was 42.6 (29–55) preoperatively and 93.9 (67–100) at last follow-up. The PMA was 8 (5–11) preoperatively and 16.7 (9–18) at last follow-up. One hip was revised to change the acetabular implant at five years. There were six early dislocations [one episode (n=4), two episodes (n=2)], one late dislocation, and two episodes of subluxation without recurrence. There were no fractures of the femoral head. The radiographic analysis identified moderate bone absorption of the calcar without real osteolysis in nearly all of the patients. For a few patients, a lucent line seen early postoperatively had disappeared at last follow-up. No implant migration (cup, stem) was noted.

Discussion: The clinical and radiographic outcomes are in agreement with the literature. The relatively high rate of dislocation can be explained by the diverse levels of experience of the surgical teams. The prostheses presenting dislocation did not have an unfavourable outcome, particularly radiographically.

Conclusion: These clinical and radiographic results at nine years follow-up, and the current systematic use of computer assisted navigation for optimal implant positioning favour continuation of the implantation of the ceramic-on-ceramic bearing in patients aged less than 65 years.


Nicolas Poilbout Philippe Poilbout Patrick Crosnier Laurent Hubert Patrick Le Nay Hafid Tahla Pascal Bizot

Purpose of the study: The Al/PE sandwich is a relatively new massive alumina insert for alumina-on-alumina prostheses using a meta-back press-fit cup. Theoretically, the advantages are a less rigid system and easier positioning and removal. The reliability is however still debated. The purpose of this study was to evaluate the 7-year outcomes of a homogenous series of 53 Al/Al sandwich total hip arthroplasties (THA) implanted without cement.

Material and methods: The series included 48 consecutive patients (53 hips) implanted by the same surgeon from 1998 to 2004 using the posterolateral approach. There were 26 men and 22 women, mean age 58 years (42–69). The prosthesis used a metal back cup totally coated with HA, an Al/PE sandwich insert, a modular anatomic femoral head with partial HA coating, and an alumina head (28 mm). All patients were reviewed and assessed clinically using the Harris score (/100) and the PMA score (/18) and radiographically using the Engh and Gruen and Amstutz scores.

Results: None of the patients were lost to follow-up and none died. One patient underwent revision surgery at 84 months for fracture of the alumina insert: the sandwich insert and the head were changed, and the outcome was very good at three years. At mean 84 months follow-up (47–109), the PMA and Harris scores were, on average, 17.7 and 98 (versus 12.3 and 54 preoperatively, p< 0.05). None of the patients complained of squeaking. There was no acetabular migration or lucency and no osteolysis. A partial and isolated lucent line was observe in the Gruen and Amstutz zone 1 and 8 of the femur in 26% of the hips. Calcar atrophy was noted in 17%. Wear was note radiographically measurable.

Discussion: The clinical and radiographic results appear to be very encouraging at mid term, illustrating the excellent resistance to wear of the alumina-on-alumina bearing, particularly in young and active subjects. With the type of implant used, the improvements provided by the anchorage of the alumina insert in the PE and the increased thickness (minimal 4.5 mm), the high rate of insert fracture reported by certain series in the literature was not observed here.

Conclusion: The absence of wear and osteolysis, improved implant design, and potential advantages in terms of positioning should make this system an attractive alternative for alumina-on-alumina implants.


Moussa Hamadouche Amine Zaoui Samer El Hage Marie Moindreau Florian Boucher Michel Mathieu Jean-Pierre Courpied

Purpose of the study: The purpose of this prospective study was to evaluated the risk of fracture of 22.2 mm Delta ceramic heads.

Material and methods: A preclinical study was performed on twenty 22.2 mm Delta ceramic femoral heads with a medium neck with 20 22.2 mm Delta ceramic femoral heads with a short neck. A V40TM cone was used in all cases with a 5 40 angle. In vitro tests consisted in the assessment of the fracture force under static pressure before and after stress tests, and with a static force shock test (Charpy model) simulating a microseparation during subluxation phenomena. Between April 2007 and April 200, a consecutive series of 55 composite Delta heads were used in 55 patients undergoing cemented total hip arthroplasty (THA). A polyethylene cup was sterilised under vacuum at 3 Mrads with a post-radiation temper (Duration®), and a stainless steel femoral piece with a highly polished surface and a V40TM Morse cone (Legend®). This series issued from a randomised prospective study designed to compare wear with 22.2mm Delta ceramic heads with stainless steel heads with the same diameter. Inclusion criteria were age < 75 years, degenerative disease on naive hip and patient residing in France. Mean patient age was 59.2±6.9 years (range 44–70).

Results: The resistance of the 22.2 mm heads was significantly less during the static tests before and after the stress tests. Nevertheless, the mean resistance was higher than the FDA recommendations of 46K. The tests simulating a microseparation showed a significantly superior resistance for the 22.2 mm heads. All patients had from 1 to 2 years follow-up (usual delay for 80% of in vivo ceramic fractures). There were no cases of femoral head fracture in this series. There were no cases of early wear at this same follow-up and no case of femoral or acetabular osteolysis.

Discussion and Conclusion: The results of this study indicate that the resistance of the 22.2mm ceramic Delta heads is very much superior to the recommendations for in vitro tests. In this series, the risk of fracture in vivo remained nil to two years follow-up. The pertinence of this ceramic implant for decreasing polyethylene wear in vivo is under evaluation.


Martin Lavigne Jean-Michel Laffosse Eric Belzile François Morin Alain Roy Julien Girard Pascal-André Vendittoli

Purpose of the study: Tribology studies of total hip arthroplasty (THA) have demonstrated that large diameter head in metal-on-metal bearings produce fewer wear particles than small diameter heads. The other advantages of this option are better stability, less dislocation, and optimal joint range of motion. The purpose of this work was to compare blood levels of chromium, cobalt and titanium six months and one year after implantation of different models of large diameter metal-on-metal THA.

Material and methods: We conducted a retrospective comparative and randomised study including 110 patients who had been implanted with a larger diameter head THA/Zimmer? Smith and Nephez, Biomet or Depuy. The metal ion concentrations (Cr, Co, Ti) were measured in whole blood by an independent laboratory using high-resolution mass spectrometry (HR-ICP-MS). Blood samples were drawn preoperatively and postoperatively at six months and one year.

Results: At six months, the concentrations of metal ions in whole blood expressed as mean (range) for Cr (μg/L) Co (μg/L) and Ti (μg/L) were, respectively: Zimmer 1.3 (0.4/2.8) 1.7 (0.9/6.8) 2.5 (0.6/6.7); Smith and Nephew 2.0 (0.7/4.2) 2.1 (0.5/6.6) 1.1 (0.5/4.1); Biomet 1.2 (0.4/2.2) 0.9 (0.3/3.4) 1.4 (0.8/2.4); Depuy 1.7 (0.5/3.2) 1.9 (0.3/4.2) 1.3 (0.5/3.9). There was a significant difference between groups for Cr (p=0.006), Co (p=0.047) and Ti (p< 0.001). The Biomet implants presented the lowest concentrations for Cr and Co; the Zimmer implants gave the highest levels of Ti.

Discussion and Conclusion: Several implant-related factors affect blood concentrations of metal ions: contact surfaces leading to “active” abrasion but also wear in other parts of the implant giving rise to “passive” corrosion. Bearing wear is related to the diameter of the head, its roughness, its spherical shape, joint clearance, the manufacturing technique (forging, casting) and its carbon content. The Biomet head corresponds to a better compromise for these different factors. Passive corrosion can result from an exposed metal surface or from metal to metal contact. This explains the high level of Ti ions found for all implants tested since titanium is not present in the bearings.


Moussa Hamadouche Frédéric Zadegan Samer El Hage Amine Zaoui Michel Mathieu Jean-Pierre Courpied

Purpose of the study: The purpose of this prospective randomised study was to evaluate the wear of cemented polyethylene cups as a function of the material of the femoral head: oxinium versus metal.

Material and methods: This series included 50 primary arthroplasties implanted from January 2006 to May 2006 in 50 patients (27 women and 23 men), mean age 60.6±11.4 years (21–75). The same femoral piece made of highly polished M30NW stainless steel with a quadrangular section was used for all implants. Similarly, all patients had a polyethylene cup sterilised with ethylene oxide (CMK21, Smith and Nephew). The femoral head was made of stainless steel for 25 hips and oxinium for 25 hips. The major outcome was penetration of femoral head into the cup (associated with true wear and creep) measured at minimum two years follow-up using the Martell method modified according to the recommendations of the author for an all-polyethylene cup. Patient-related and technique-related factors were studied. Non-parametric tests were used for the statistical analysis.

Results: There was no significant difference between the two groups regarding preoperative data. Two patients died, one was lost to follow-up; for three patients, the radiographs were excluded by the software. The analysis thus included 44 hips with a median follow-up of 2.01 years (1.9–2.3), 22 in the Oxinium™ group and 22 in the metal group. The median penetration rate was 0.16 mm/year in the Oxinium® group versus 0.19 mm/year in the metal group (Mann-Whitney, p=0.46). Annual volumetric penetration in the Oxinium™ group was comparable with that of the metal group (Mann-Whitney, p=0.76). conversely, using the radiograph taken at one year as the reference value (true wear), wear was 0.066 mm/y in the Oxinium™ group versus 0.19mm/y in the metal group (Mann-Whitney, p=0.38).

Discussion and Conclusion: The results of this series indicate that using an oxinium femoral head reduces polyethylene wear. Mid-term results appear to be necessary to confirm these findings.


Cédric Pelegri Grégory Moineau Alexandre Roux Alexis Pison Christophe Trojani Anne Frégeac Fernand de Peretti Pascal Boileau

Purpose of the study: Optimal management of proximal fractures of the humerus remains a subject of debate. We conducted a prospective epidemiological study to identify injuries encountered, determine the reproducibility of reference classifications and their pertinence for therapeutic decision making.

Material and methods: All patients presenting a proximal fracture of the humerus admitted to a teaching hospital from November 2007 to November 2008 were included using a standardised computer form. A CT-scan was obtained if necessary. Fractures were classified by three senior observers (CP, GM, AR) according to the Neer and AO classifications.

Results: Two hundred forty-seven fractures were collected in 75 men (30%) and 172 women (70%), mean age 66 years (18–97). There were 112 fractures on the dominant side (45%). Two patients had vessel injury and one an associated injury of the brachial plexus. One patient had an isolated injury to the axillary nerve. According to the Neer classification which describes 15 types of fractures, there was little or no displacement or 38% of the fractures and 97.5% of the fractures were classified within six groups: little or no displacement, surgical neck, trochiter fracture alone or with anterior dislocation, 3 or 4 fragment fractures. Using the nine subtypes of the AO classification, there were 58 A1, 55 A2, 42 A3, 43 B1, 9 B2, 5 B3, 14 C1, 18 C2 and 3 C3. Groups A and B included 88% of the fractures. Regarding the CT-scan, obtained in 40% of patients, changed the radiographic interpretation in six cases. Interobserver reproducibility was good. Orthopaedic treatment was given for 203 patients (82%). Operations were: fixation of the tuberosities (n=7), anterograde nailing (n=29), hemiarthroplasty (n=6), reversed prosthesis (n=2).

Discussion: This distribution of fractures of the proximal humerus corresponds well with data in the literature. Good quality x-rays can provide adequate classification without a CT-scan for the majority of patients. The classification systems currently used are quite exhaustive although the distribution in the subgroups is not homogeneous.


Georges Laval Patrick Dohn Julien Amzallag Redouane Jalil Paolo Fillippini Alexandre Poignard Philippe Hernigou

Purpose of the study: The alumina-polyethylene bearing has been used for many years but no study has evaluated polyethylene wear and osteolysis with a 32 mm head with a follow-up exceeding 20 years.

Material and methods: Thirty-six arthroplasties implanted between 1983 and 1985 (26 patients, mean age 54 years, range 35–65 years) were studied. The same cemented implants were used in all cases, with no loosening. Penetration of the head into the polyethylene was measured annually on digital radiographs and with computer assistance. Osteolysis was quantified in mm2 on the merckel.

Results: At 20 years follow-up (minimum) or more, penetration of the femoral head into the cup was on average 0.07mm/y. The characteristic feature of the wear curve was the perfect stability after the third year and the absence of any increase over time. Extrapolation of the straight part of the curve to the origin determined the creep. True wear was limited: 0.05mm/y. It was not modified by the polyethylene thickness (eight 52mm cups, twenty-three 50mm and five 48mm). Corresponding volumetric wear was estimated at 640 mm3 at maximum follow-up. At last follow-up, osteolysis measured in mm2 on the meckel was 65 mm2 on average. In general, this osteolysis appeared around the second year with an imprint on the merckel; it then increased linearly and regularly to the 20th year. Acetabular osteolysis was nevertheless greater than that observed with the Al/Al bearing of controlateral hips implanted at the same period when evaluated on the scan for both hips (20 cases).

Discussion: The alumina-polyethylene bearing enables long implant survival for at least 20 years, even for relatively thin polyethylene thicknesses. The characteristic feature of the bearing is the linear polyethylene wear which does not increase with time but remains constant, undoubtedly in relation to the absence of any change in the roughness of the head despite the very long follow-up. Osteolysis remains minimal, but superior to that observed with Al/Al bearings implanted during the same period in controlateral hips.


Mazen Ali Fredson Razanabola Luca Capuano Paul Rabenirina Walid Aryan Didier Yaffi

Purpose of the study: Fracture dislocations are complex injuries compromising elbow stability and functional potential. The treatment of these injuries should restore the exact anatomy of the joint, the only guarantee for a good functional outcome. The purpose of our work was to analyse our results and review the literature in order to establish an evidence-based therapeutic algorithm essentially based on the type of associated fracture.

Material and methods: This was a retrospective analysis of 15 cases (12 men, 3 women) reviewed at mean 18 months. The causal event was a fall in most patients, followed by traffic and sports accidents. This was a first-intention treatment for 12 patients and a second-intention intervention for three. Initially, none of the patients presented vessel or nerve injury. There were three open fractures. The most common fracture was: radial head (n=12), coronoid process (n=9). One or two approaches were used, depending on the type of associated fracture. Treatment consisted in fixation of the radial head (n=8) and arthroplasty (n=4).. The coronoid process was fixed in six cases. All ligament tears were repaired. An articulated external fixator was used in four cases.

Results: All patients had a stable elbow. Mean flexion was 125, extension -16, pronation 72 and supination 63. Wrist force was 80% compared with the controlateral side. The Mayo Clinic function score was 84 points.

Discussion: Reconstruction of the lateral osteoligament column, associated with fixation of the coronoid, restores stability in the majority of elbows. For very high energy injuries with complex bone and ligament damage, addition of an articulated external fixator is indispensable to enable early mobilization. Stiffness and instability are the most common complications after traumatic injury.

Conclusion: Fracture dislocations of the elbow are complex injuries requiring adequate emergency care, with surgery as needed, for all lesions at the same time via one or two approaches followed by early rehabilitation. The function outcome depends on the intraoperative stability achieved and early mobilization.


Harald Kuhn Carsten Vossmann

Purpose of the study: The design of the NANOS femoral stem defined in 2002 is based on anatomic studies and the analysis of 578 scanner slices. The stem is plasma torch coated with titanium and with calcium phosphate to accelerate the osteointegration process. The NANO stem is indicated for young active patients with BMI < 30 and free of coxa vara/valga.

Material and methods: This was a multisite study conducted in five hospitals and including 205 patients; follow-up was 12 months for 77 patients and 24–36 months for 50. For the patients followed for 12–24 months, indications were: primary degenerative disease (n=110, 51.4%), dysplasia (n=57, 26.6%), necrosis of the femoral head (n=32, 15%), other causes including Perthes disease, epiphysiolysis, posttraumatic osteoarthritis, protrusion. Mean patient age was 57.4 years (33–80). There was no case of stem migration or dislocation.

Results: Mean mobility (Merle-d’Aubigné) was 5.49 in 205 patients preoperatively, 5.97 in 73 patients at 12 months and 6.6 in eight patients after 18 months. Pain and walking were scored 7.51 (Merle-d’Aubigné) in 205 patients preoperatively, 11.7 in 77 at 12 months, then 11.96/12 at 24–36 months. The HSS score improved from 47.8/100 preoperatively to 96.62/100 at 24–36 months (50 patients). Outcome was good in more than 280 implants, mainly inserted via an anterolateral approach.

Discussion: Biomechanical studies have demonstrated the advantages of implanting the NANOS prosthesis via a MIS approach: mini-incision, net diminution of undesirable stress. The partially spared femoral neck can be used as an anchorage zone, favouring primary stability. The fine neck of the NANOS stem avoids impingement and increases joint range of motion.

Conclusion: The early results indicate a high level of patient satisfaction and the clinical and radiographic findings suggest good long-term outcome can be expected.


Jean-Marie Chirpaz-Cerbat Sébastien Ruatti

Purpose of the study: Defective reduction and secondary displacement after osteosynthesis of distal radius fractures can compromise wrist function. Volar locking plates enable solid fixation which remains stable over time but section of the pronator quadrates necessary for the anterior approach raises the risks of destabilising the distal radioulnar joint and loss of pronation force. Our study was designed to evaluate recovery of grip, pronation and supination force after volar locking plate fixation.

Material and methods: This was a prospective study of 29 fractures of the distal radius with dorsal displacement fixed with a volar locking plate in 28 patients (17 men, 11 women, mean age 48.75 years) from January 2007 to May 2008. The quality of the pronator quadrates suture was assessed at the end of the operation. The assessment included the classical parameters of wrist movement, the Herzberg and Dumontier score, radial slope and ulnar variance on the ap and lateral views of the wrist, and recovery of grip, pronation and supination force compared with the opposite side using an ambulatory device.

Results: The pronator quadratus suture was considered solid in eight cases, precarious in seven. Complete suture was not possible in 14 cases. At mean follow-up of 10 months, patients had on average recovered 77% of the grip force, 74% of the pronation force, and 76% of supination force, compared with the opposite side. Complications included one defective reduction, one secondary displacement (by defective plate position), two dystrophy syndromes, and four posttrauma carpal tunnel syndromes.

Discussion: The literature shows that volar plate fixation enables recovery of 74% to 84% of grip force. Few studies have examined the recovery of pronosupination and none have described results after osteosynthesis for fracture. Our study did not find that section of the pronator quadrates, a muscle difficult to suture, had a deleterious effect.

Conclusion: Osteosynthesis using a volar locking plate for distal fractures of the radius remains a controversial issue. Study of recovery of the grip, pronation and supination force did not reveal any prejudice attributable to this technique.


Christophe Gaillard Ayman Tayeb Marie-Laure Louis Marianne Helix Georges Curvale Alexandre Rochwerger

Purpose of the study: Although the role of the radial head is clearly established regarding elbow stability, it cannot always be preserved after complex fractures. Association with a posteriolateral dislocation, besides the risk of short-term recurrent dislocation, raises the problem of long-term osteoarthritic degeneration. Certain authors advocate a metal prosthesis which works like a spacer in lieu of the head; their mid-term results have been encouraging, but should complete resection with suture of the medial ligament plane be ruled out definitively?

Material and methods: We reviewed 13 files of patients who had had an initial resection of the radial head after trauma. For seven of these patients, there was an associated dislocation; the medial ligament structures were sutured. All patients were reviewed with mean 13 years follow-up (5–15) and evaluated clinically with the American Shoulder and Elbow Surgeon (ASES) system to establish the Mayo Clinic Elbow Performance (MCEP) score. Osteoarthritis of the ulnar trochlea was analysed on the plain x-rays, completed by an axial view, using the Morrey radiographic classification of 4 stages.

Results: There were not cases of recurrent dislocation. According to the Broberg and Morrey index, 92% of patients had good outcome with total resumption of occupational activities; there was no difference between patients with and without dislocation. All patients developed grade 1 or 2 osteoarthritis, with very good clinical tolerance. All were satisfied with their operation despite efforts to spare joint movements.

Discussion: The studies evaluating the use of radial head prostheses have reported similar findings for functional outcome. Radiographic degeneration of the ulnar trochlea is also comparable. Immediate rehabilitation is necessary to prevent loss of range of motion and warrants surgery to stabilize the joint as wells as possible use of an adapted dynamic orthesis.

Conclusion: Resection of the radial head without prosthetic reconstruction remains a reasonable option when the head cannot be saved. Associated dislocation implies repair of the medical collateral ligament. At long-term, the functional impairment is minimal despite the moderate osteoarthritis; the problematic of implant survival is avoided.


Pierre-Sylvain Marcheix Anthony Dotzis Julien Siegler Pierre-Étienne Benkö Christian Mabit Jean-Paul Arnaud Jean-Louis Charissoux

Purpose of the study: The purpose of this study was to compare two types of treatment for fractures of the distal radius with posterior shift: the volar locking plate (c) or mixed multiple pinning (MMP). We conducted a prospective randomised trial.

Material and methods: One hundred ten patients aged over 50 years victims of an articular or extra-articular fracture of the distal radius with posterior shift were included in this study. Mean age was 74 years. Patients were recruited via our emergency unit. After obtaining the written informed consent of the patients, patients were assigned to a treatment group using the nQuery Advisor 6.01 available on the internet, 24 hours/d 7d/7. Patients were treated by one of the two surgical techniques according to the randomisation. Patients were reviewed at 3 and 6 weeks and at 3 and 6 months. The DASH and Herzberg scores were noted and plain x-rays of the wrist (ap and lateral views) were obtained at each visit.

Results: Fifty-two patients were treated with MMP and 50 with VLP. Postoperative anteversion of he radial glenoid was significantly better in patients treated with MMP. At six months, the DASH and Herzberg score were significantly better in the LAP group.

Discussion: MMP allows better anteversion of the glenoid than VLP. However, with MMP there is a risk of over reduction (15% of patients in our series). Treatment with VLP should enable restoration of better radius length with a lesser loss at three months than with MMP. All studies reported, irrespective of the function score used, have found better functional outcome with plating than with pinning.

Conclusion: MMP offers a less costly alternative for the treatment of most all distal fractures of the radius with posterior shift. This option provides quite satisfactory clinical and radiographic outcomes. There is a risk of postoperative defect in reduction or stability with MMP, suggesting surgeons should opt for another technique, VLP for example.


Yannick Delannis Pierre Mansat Nicolas Bonnevialle Olivier Peter Bruno Chemama Paul Bonnevialle

Purpose of the study: The articulated external fixator of the elbow joint is often useful for the treatment of trauma victims. It can neutralise dislocation forces and protect osteosynthesis assemblies and ligament repairs while authorising early mobilisation. This work reports our indications and application of this type of fixator, as well as the expected clinical and radiographic outcomes.

Material and methods: From 1995 to 2008, 34 patients had an external fixator of the elbow in our unit, in combination with classical treatment. Two groups of patients were distinguished, those with a traumatic injury requiring emergency care (n=15, group 1: six dislocations, two fracture-dislocations, and seven complex fractures), and those treated outside an emergency context (n=10, group 2: ten chronic dislocations or subluxations, four stiff joints, one infection, four material disassemblies). Eighteen patient were reviewed retrospectively, clinically and radiographically. The DASH score and the Mayo Elbow Performance Score (MEPS) were noted. The Broberg and Morrey classification was used for osteoarthritis.

Results: At mean 4.3 years follow-up, for groups 1 and 2, the DASH scores were 35 and 25 points and the MEPS scores 74 and 74 points respectively. In group 1, the range of motion was 63° for flexion-extension; the elbow was centred and stable in all cases except 2 (one posterior subluxation). Six elbows presented moderate to severe osteoarthritis. In group 2, the range of motion was 80° flexion-extension; the elbow was centred and stable in all cases except one (one posterior subluxation). Moderate to severe osteoarthritis was noted in five elbows. There were four complications: two cases of transient (ulnar and radial) paralysis, one fracture of the humerus on a pin track, and one superficial pin track infection.

Discussion: This study demonstrates that the articulated external fixation can maintain the reduction during the healing process for complex elbow trauma where stability is compromised. The morbidity is low and functional outcomes favourable. Early mobilization of these injured elbows can limit secondary stiffness. The prognosis remains a function of the initial injury and the quality of the associated treatments.


Abdelhakim Bentounsi Abderrahmane Bourahla Mahdjoub Bouzitouna Rabah Maza

Purpose of the study: Fracture of the medial condyle of the humerus is uncommon in adults. The purpose of this retrospective analysis was to examine the clinical and radiographic outcomes of a single-site series.

Material and methods: From January 1990 to December 2004, nine closed fractures of the medial condyle of the humerus were treated surgically in seven men and two women, mean age 31.22 years (range 16–65). No vessel or nerve injury was noted at diagnosis. According to the AO/ASIF classification, all fractures were type B2. Surgery was undertaken on day 2 to 6, via a medial or posterior approach for pin or screw fixation. Postoperatively, the joint was held immobile with a brace for 5.57 weeks (3–8.). Functional and physical outcome were studied using the Mayo Clinic Elbow Performance score. Bone healing and secondary osteoarthritis were assessed on plain x-rays.

Results: Six patients were reviewed at mean follow-up of 9.31 years (4.31–16.56), three patients were lost to follow-up. There were no infections. Four patients experienced sensorial disorders in the territory of the ulnar nerve including three with persistent symptoms at last follow-up. Two elbows were slightly painful at last follow-up. Two patients aged 16 and 18 years at trauma exhibited exaggerated valgus. Material was removed for three patients. Mean flexion was 123.83 (90–140), mean extension deficit 3.33 (−10 to 0), mean pronation 82.5 (70–85), mean supination 90, the flexion-extension range 122.16 (90–130). The Mayo Elbow Performance Score was 89.16 (65–100), one patient was dissatisfied, three patients exhibited moderated joint impingement. Hypertrophy of the medial condyle was noted in three patients. All fractures healed.

Discussion: These fractures are rare in adults. Few series are reported in the literature, with small populations. The mechanism of the injury can be direct shock on a flexed elbow or indirect shock by fall onto the hand. Valgus deviation and hypertrophy of the medial condyle in adolescents appear to be secondary to secondary growth stimulation. The combination of the initial injury, imperfect reduction, and prolonged postoperative immobilization influences the functional outcome.

Conclusion: This work confirms that surgery alone, associating perfect reduction and rigid fixation, can enable early rehabilitation and improved results.


Laurent Obert Sonia Huard Nicolas Blanchet Grégoire Leclerc Xavier Ghislandi Séverin Rochet Patrick Garbuio

Purpose of the study: Volar plate fixation is becoming increasingly popular for instable fractures of the distal radius or on porotic bone. We report our experience and unavoidable or predictable complications with this type of fixation.

Material and methods: The 142 patients who underwent surgery from 2006 to 208 were reviewed and followed prospectively. In 2006 and 200, three types of volar plates were implanted: the Ace Depuy (standard), the T or DRP (Synthes), prolock with locking screws, (ITS) with a series of 104 patients. In 2008, two types of new generation plates with a more anatomic design were used: Variax (Stryker) and Newclip with a series of 48 patients. Complications were noted with minimum four months follow-up.

Results: All fractures healed. The Herzberg score reached 81/100 and the DASH 19.4. The complication rate was 19% (n=19) for the older generation plates and 15% (n=7) for the new anatomic plates. The main complications were tears of the long flexor and long extensor pollicis tendons (two before 2008 and four after 2008), reflex dystrophy (five before 2008 and two after), carpal tunnel syndrome (n=4), and material problems (dislodged screw, protruding screw) with no functional consequences (six before 2008 and one after).

Discussion: The increasing popularity of plate fixation for distal radius fractures generates an increase in complications. These are predictable if the material protrudes (tendon tears caused by overly long screws). Three published series on these specific complications (Rozental 2006, Rampoldi and Arora 2007) found that these problems could be avoided, both by implant design and by surgical technique. Locking the epiphyseal screws requires insertion into the subchondral bone and thus distal implantation of the plates, generating an iatrogenic conflict for the flexors. The rediscovery of the anatomy of the distal radius should help avoid styloid problems, and reconsideration of plate design to avoid advancement both on the ulnar side and the radial side. While the extra-articular volar plates fulfil the same function as pinning (Obert 2006), plates have lower indirect costs than pinning + plaster cast (Candelier 2006). Conversely, there is still no proof of the superiority of locked screws over standard screws.


Philippe Candoni Antoine Bertani Emmanuel Soucanye de Landevoisin Christophe Drouin Éric Demortière

Purpose of the study: Treatment of comminutive fractures of the distal radius in elderly subjects remains a debated issue. Use of locked plates has given interesting results, particularly in the young subject. External fixation remains the simple osteosynthesis technique with the advantage of being minimally invasive and well adapted to the quality of bone in the elderly subject. The purpose of this work was to evaluate the mid-term results of a series of radiometacarpal joint bridgings of comminutive fractures of the distal radius.

Material and methods: From January 2003 to December 2007, 44 radiometacarpal fixations were assemblied and included in a retrospective radioclinical study. All of the fractures were comminutive (AO classification: C2 20.4%, C3 79.6%) in subjects aged over 60 years. Surgery consisted in a radiocarpal assembly alone (25%) or associated with another fixation (75%). The PRWE score was used for the functional assessment and the Sofcot 2000 symposium criteria for the radiographic analysis. Factors of poor prognosis were studied.

Results: Forty-four patients were reviewed with a mean follow-up of 28 months. Five patients were lost to follow-up. All patients had healed at mean 6.8 weeks. The functional outcome was good or very good in 45.4% of patients. Radiographically, anatomic restitution was achieved in 15.9% with a moderate to severe callus deformity in 84.1%. Fifteen complications were noted: reflex dystrophy (n=5), neuroma (n=2), material migration (n=6), disassembly with surgical revision (n=2) and superficial infection (n=2).

Discussion: Unlike observations in the young subject, there does not appear to be a consensus on the treatment of comminutive fractures of the distal radius in the elderly osteoporotic subject. External fixation has been used for many years for comminutive fractures. Our results nevertheless illustrate the limitations of this technique, both in terms of the functional outcome (54.6% insufficient results) and radiographic outcome (84.1% callus deformities). The only good results obtained with the external fixator occurred when the technique was associated with another fixation method. This suggests we should consider fixation of the wrist as a temporary osteosynthesis which should be replaced by another method (locked plating).


Michel Rongières Rachid El Ayadi Antoine Dumont Paulo Peirera Alexa Gaston Costel Apredoaei Pierre Mansat Paul Bonnevialle

Purpose of the study: Both conventional plates (CP) and volar locking plates (VP) are used for the ttreatment of distal fractures of the radius (Crognet 2006, Jupiter 2009). This was a retrospective analysis to compare the respective results of these two plating methods with a one year follow-up and to study the clinical outcomes and quality and duration of the reduction achieved.

Material and methods: From 2005 to 2008, 48 CP and 33 VP were inserted for the same indications, simultaneously in the same unit. The four operators chose the material as needed. The time to treatment was less than 12 hours for 81% of patients. For CP, the fractures were comminutive in 60%, articular in 40% and associated with ligament injury for more than 10%. For VP, the fractures were comminutive in 80%, articular in 86% and in a context of multiple trauma in 20%. The clinical analysis included range of motion, index of reduction (IR), stability (IS) and efficacy (IF) defined at the SOFCOT symposium.

Results: For the two series, the mean range of motion was flexion-extension 118, pronosupination 166; the recovered force was > 75% of the controlateral side. The QuickDash was excellent in more than 75%, good in 10%, fair in 10%, poor in 5%. More than 75% had an anatomic result. Complications were the same in percentage and in type for the two types of plates with no significant difference. For the VP, 95% of the clinical and radiographic outcomes were good or very good. For the CP, the results were the same. There was only one real loss of reduction with migration of an epiphyseal screw with no observable clinical impact.

Discussion: This study was limited by the non randomization; there was a difference in the type of injury between the two series. Use of non-locked plates for fractures of the distal radius has proven efficacy as amply noted in the literature. This was analysed, and in particular with a few comparative CP/VP studies. Locking the volar plate does not guarantee stability in fragile cancellous bone. The problems encountered when removing the VP were not within the scope of this work. The cost of locking can limit systematic use. These two types of plates should not be considered in opposition but rather as complementary techniques.


Rachid Saddiki Alain Harisboure Xavier Hemery Xavier Ohl Reda Kabbaj Émile Dehoux

Purpose of the study: Within the framework of a regional study, we compared the efficacy of pinning using the PY technique and the Kapandji method for the treatment of fractures of the distal radius with posterior displacement.

Material and methods: This was a prospective study designed as a phase III randomised therapeutic trial in parallel groups. An open monocentric study with multiple operators compared the PY and Kapandji techniques. Two comparable groups were established: the PY group and the Kapandji group (K) for which we measured: quality of reduction using the radiographic frontal and sagittal radial inclination (FRI and SRI), radial length and inferior radioulnar index. Objective and subjective functional outcome assessed range of motion and the DASH and Jakim scores. The quality of the intra-articular reduction of articular fractures was assessed arthroscopically at the time of implant removal during the sixth week.

Results: The series included 97 patients followed for one year. The preoperative FRI was 15.17 with mean posterior shift of −19.2. At one year, the RI was 25.5 in the PY group versus 22.6 in the K group (p=0.009) and the SRI 10.5 in the PY group versus 3.7 in the K group (p=0.04). For fractures with a posteromedian fragment and Gerard-Marchand fractures, the DASH at one year was 2 in the PY group versus 32 in the K group. The Jakim score was 71 in the PY group versus 58 in the K group (p=0.03) for posteromedian fragment fractures. The arthroscopic control at six weeks of articular fractures did not reveal any significant difference in intra-articular reduction. There were no tendon tears in this series.

Discussion: This series shows the quality of pin fixation for wrist fractures, comparable with plating. It emphasizes the importance of adapting the type of pinning to the fracture type and the patient.

Conclusion: Treatment of fractures of the distal radius with posterior displacement with pin fixation remains a treatment of choice, reserving PY osteosynthesis for fractures with a posteromedian fragment and Gerard-Marchand fractures and Kapandji osteosynthsis for simple Colles fractures.


Anthony Wajsfisz David Biau Philippe Beaufils

Purpose of the study: Certain patients with a total knee arthroplasty (TKA) require large range of flexion postoperatively to enable squatting and sitting cross-legged. Several factors have an effect on this flexion, including prosthesis design. The purpose of this study was to examine the influence of prosthesis design on intra- and postoperative flexion of three modes of TKA with a pure rotational mobile plateau: two NexGen posterostabilised (PS) prostheses (LPS-Standard and LPS-Flex) and one ultracongruent prosthesis (SAL). It was hypothesised that PS prostheses would have a better flexion than the ultracongruent prosthesis and that the flexion would be greater with the LPS-Flex than the LPS-standard.

Material and methods: This was a prospective randomised study of consecutive patients from January 2006 to January 2007 to compare maximal flexion for each model. All patients requiring a first-intention TKA were included in this study. Seventy-tow TKA were studied: LPS-standard (n=24), LPS-Flex (n=22), SAL (n=26). Flexion was measured pre and postoperatively goniometrically. Intraoperative measures were made with the navigation system (Navitrack-Orthosoft). Minimum follow-up was one year.

Results: There was a significant difference in flexion, intraoperatively and at last follow-up, in favour of the PS models over the ultracongruent SAL. Conversely, there was no significant difference between the LPS-standard and the LPS-Flex. The analysis of factors predictive of flexion were the SAL model with a negative influence (loss of 8° intraoperatively [p< 10-4] and 15° at one year [p< 10-4] compared with the LPS models). Preoperative flexion appeared to be a positive predictive factor (p=0.00023).

Discussion: The design of the TKA has an influence on knee flexion: from implantation, flexion of the PS models was superior to the ultracongruent model, a difference which persisted late after the operation. For the PS models, the LPS-Flex model presented as a large flexion model did not, in our study, demonstrate its superiority over the LPS-standard model, irrespective of the time of the comparison. It should be noted that for implantation the LPS-Flex model required a posterior cut 2mm more than for the LPS-standard. Good preoperative flexion is an essential factor for obtaining good postoperative flexion, irrespective of the model implanted.


Polyclinique le Languedoc, avenue de la Côte-des-Roses, 11100 Narbonne 7885

Purpose of the study: The goal of navigation for TKA is to improve the precision of the frontal alignment. Continuing this objective, we were interested in a different option than navigation: we wanted to optimise traditional instrumentation and associated an implantation procedure with a rigorous radiographic planning system.

Material and methods: This was a consecutive series of 100 TKA all implanted by the same operator; pre- and postoperative goniometry was performed in the same radiology unit and controlled by the same radiologist. Preoperative planning was based on the weight-bearing goniometry with a femoral valgus varying from 3 to 11, in order to obtain a distal femoral cut strictly orthogonal to the mechanical axis. The tibial cut, independent of the femoral cut was also orthogonal to the tibial axis. The instrument sent enabled in situ correction, with 1° precision, of the angle of the femoral and/or tibial cut if it was different from the preoperative measurement; tibial insertion was mixed (centromedullary and controlled by an extramedullary system).

Results: Mean patient age, male-female ratio and varus/valgus were comparable with other series. The mean postoperative HKA angle was 180±2.3°. Alignment varied from 0 to 2° in 70 patients. Defective alignment of 2 to 3° was observed in 14 patients, i.e. 92% of knees within 3°. Eight patients were misaligned at 3 to 5° which was the greatest deviation in this series.

Conclusion: These results demonstrate that the quality of TKA implantation can be improved, in particular implant alignment, by optimising the operative technique and the surgical material and associating simple radiographic planning, without necessarily using navigation systematically.


Marc Soubeyrand Sabri Mahjoub César Vincent-Mansour Olivier Gagey Véronique Molina David Biau Charles Court Jean Michel Bernhardt Ciritsis

Purpose of the study: Percutaneous screw fixation is widely used for the treatment of non-displaced fresh fractures of the carpal scaphoid. This screw fixation can be achieved either via a volar approach (retrograde insertion) or via a dorsal approach (antegrade insertion). The purpose of our study was to define the best approach as a function of the orientation of the fracture line (types B1 or B2 in the Herbert classification).

Material and methods: We used 12 upper limbs. For each wrist we obtained three scanner images: in maximal flexion, in the neutral position, and in maximal extension. For each scanner image, the parasagittal slice corresponding to the ideal plane for screw position was identified by digital reconstruction. On each slice, the type B1 and B2 fractures were modellised, as was the displacement of the corresponding screws introduced via the volar incision (S1) or the dorsal incision (S2). Each virtual screw was positioned as perpendicular as possible to the fracture line. For each slice corresponding to a given wrist position, we measured the angles between the fracture line (B1, B2) and the screws (S1, S2), giving four angles V1 (S1-B1), V2 (S1-B1), D1 (S2-B1), D2 (S2-B2). Thus the angle closest to 90° was considered the most satisfactory.

Results: For B2 fractures, the position of the virtual screw perpendicular to the fracture line was possible via both the volar and the dorsal incision. For B1 fractures, it was impossible to position the screw perpendicular to the fracture line, but the dorsal approach with the wrist in maximal flexion gave the best position.

Conclusion: For B2 fractures, the dorsal and volar approach allow optimal screw insertion so the choice of the incision depends on the surgeon’s experience. For B1 fractures, we recommend the dorsal approach.


Sébastien Parratte Marc Since Vanessa Pauly Jean-Manuel Aubaniac Jean-Noël Argenson

Purpose of the study: It has been demonstrated that the anatomy of the distal femur differs by gender. The ratio of the mediolateral/anteroposterior distance, the shape of the distal femur, and the orientation of the trochlea differ between males and females. To adapt to these differences, prostheses specifically designed for female patients (TKAgender) were developed. The purpose of our study was to compare the first objective and subjective outcomes with these prostheses.

Material and methods: Thirty women who underwent bilateral surgery within a six month interval for degenerative joint disease of the knee between March 2006 and March 2008 were included in a comparative prospective study. The side receiving the gender implant was determined at random. Operative and postoperative protocols were the same excepting the femoral implant. Patients were not informed of which knee had received the gender prosthesis. Mean age in this series was 67 years and mean BMI 26. All implants were cemented. At minimum one year follow-up, objective and subjective analysis included specific questions concerning preference and quality of life presented by an independent observer.

Results: The Knee Society clinical scores were comparable in the two groups, as were the results for the different items of the KOOS score. For preferences: the patients preferred the gender knee in 75% of the cases (p< 0.01), they reported less noise or cracking sounds in the anterior part of the knee for 68% (p=0.03) and had the impression that the knee recovered faster in 64% (p=0.04).

Discussion: To our knowledge, this is the first report of results concerning implants specifically designed for female patients. At short-term, the only difference in the patients’ preference was a subjective feeling of less impairment for the patellar track. It will be interesting to follow these patients to assess the long-term impact on the patellofemoral articulation.


Michel Bercovy Damien Hasdenteufel Nicolas Legrand Sébastien Delacroix Michel Zimmerman

Purpose of the study: How does a total knee arthroplasty (TKA) function? Do all prostheses provide the excellent results reported in the literature? This gait analysis compared patients with a TKA versus normal subjects in order to obtain a 3D quantification of the kinematic and dynamic differences between patients with a very good functional result and controls.

Material and methods: Twenty patients who had a TKA for less than one year and whose functional outcome was scored very good (KSS knee > 85/100, VAS ≤1/10) were compared in a double blind study with 20 normal controls. The knees were masked so that the investigators were unaware of the type of subject (operated or not), the side operated, or the type of implant. The analysis as performed on an AMTI platform with six infrared cameras which followed the displacements of 36 reflectors. Motion Analysis software was applied. The gait parameters recorded were: speed, step length, flexion angle, duration of weight bearing/oscillation phases, and dynamic variables: flexion-extension moment, varus-valgus moment, internal/external rotation moment.

Results: Adjusted for age and height, step length, walking speed, and duration of the weight bearing phase were identical in the operated and control populations. Kinematic and dynamic variables demonstrated significant differences. At lift-off, all of the TKA subjects were in functional permanent flexion (m=10); the flexion moment of the quadriceps was less than in the non-operated subjects. In the frontal plane, the weight-bearing phase was identical between the operated subjects and controls, but with a varus dynamic (m=4) during the oscillating phase. In the horizontal plane, there was an external rotation of the tibia (m=+5) during weight bearing.

Discussion: Gait analysis provides quantitative information which is not perceptible at physical examination nor with videoscopic explorations. Even patients with an excellent KSS score exhibit important anomalies despite the fact that the physical exam finds a normal range of motion and normal muscle force. The degree by degree 3D gait analysis reveals the difference.

Conclusion: Despite a clinical score considered to be very good, patients with a TKA have a functional deficit of the extensor system during take-off, even when the knee has complete active extension; the weight-bearing phase of the step is in external rotation and the oscillating phase exhibits varus laxity.


Frédéric Picard Stephen Page Nadine Willcox Angela Deakin Jean-Baptiste Pinzuti Anthony Payne

Purpose of the study: Rotation of the tibial implant is an important factor for the functional outcome of total knee arthroplasty (TKA). Any rotational malposition will cause eccentric loading of the plateau. Several techniques have been recommended to avoid malposition, but none has proven superior over the others in terms of reliability or reproductibility. The landmark used to establish rotation must meet two prerequisites: easy identification and reliable representation of the anatomic rotation of the proximal tibia. This study was conducted to compare seven different techniques for landmarking used for choosing the rotation of the tibial base in TKA.

Material and methods: An optoelectronic method was used to measure 50 tibia selected among a collection of 600 skeletons. A palper was used to locate 34 distinct landmarks and institute each reference system. The groups of anatomic points were reconstructed to form lines and plans depending on the comparisons to make: posterior condylar alignment (PCA), transversal alignment (TA), anterior condylar alignment (ACA), alignment of the anterior tibial tuberosity (ATT), the transmalleolar alignment (TMA), the line of the tibial crest (LTC) and a new line, the anterior distal line (ADL). The PCA was used as the reference.

Results: Intra-observer variation was determined in a preliminary study using ten consecutive measurements. The standard deviation was 0.5° with a distribution of 1.8°. Angle: mean [-:internal rotation; +external rotation], standard deviation: difference between the minimum and the maximum. TA: −5.13; 9.2; 38.03; ACA: −12.81; 6.7; 41.74; ATT: 68.72; 8.6; 58.46; TMA: −22.68; 11.6; 72.84; LTC: 67.56; 10.3; 46.11; ADL: 16.61; 13.2; 74.93.

Discussion: This study did not prove convincingly that any one of the tibial alignments was better than another; which demonstrates that use of a single reference is probably inappropriate to determine the rotational alignment of the tibial base for TKA. It was noted however that the anterior condylar line (mean external rotation 12.8°-SD< 7° relative to the PCA) could be pertinent for future research since this line is easily accessible and palpable, particularly during navigated surgery.


Jean-Yves Jenny Bruno Barbe

Purpose of the study: It has been demonstrated that navigation systems improve the quality of implantation of total knee arthroplasty (TKA). The definitions of the reference alignment for the femur are not however consensual. We wanted to define the different alignments of the femur on the lateral view, including the femoral head and comparing the alignments with those defined by the measured axes during navigated implantation.

Material and methods: We analysed 30 navigated TKA or unicompartmental prosthesis implantations. The following lines were drawn on the pre and postoperative lateral telemetric views: anatomic axis aligned on the anterior cortical of the femur, mechanical alignment n°1 (centre of the femoral head to the most distal point of the Blumensaat line), mechanical alignment n°2 (centre of the femoral head to the junction between the anterior two-thirds and the posterior third of the femoral condyles). The anatomic diaphyseal alignment was taken as the reference and the angles between this reference line and the other lines was measure. In addition, the sagittal orientation of the femoral component measured during the operation by the navigation system in relation to the n°2 mechanical alignment was noted; this orientation was also measured on the postoperative lateral telemetric views in relation to this same mechanical alignment.

Results: The mean difference between the anatomic cortical alignment and the reference was 0.3 (−1 to +). The mean difference between the n°1 mechanical alignment and the reference was −1.1 (−5 to +3). The mean difference between the mechanical alignment n°2 and the reference was 0.8 (−4 to 4). The mean intraoperative sagittal orientation of the femoral component was 0.0 (−2 to 2). The mean postoperative sagittal orientation of the femoral component was 1.1 (−4 to 6).

Discussion: The differences between the orientations of the different sagittal alignments of the femur were minimal. The cortical axis has a smaller variance and could be considered as the most reliable reference, but this alignment does not include the femoral anteversion. The difference between the sagittal orientation of the femoral component as measured by the navigation system and as measured on the postoperative x-rays was also minimal, and probably of no significance clinically.

Conclusion: The choice of the sagittal alignment of the femur is of little importance. The intraoperative navigated measurement of the sagittal orientation of the femoral component is reliable.


Ana Torres Eduardo Solis Angel Torres Antonio Murcia Mazon

Purpose of the study: Despite the help provided for positioning the implants for total knee arthroplasty (TKA), the clinical pertinence of navigation remains a subject of debate. The purpose of this study was to analyse the clinical and radiological outcomes of TKA implanted with and without navigation and to assess the morbidity related to use of the system.

Material and methods: This was a prospective comparative study including 105 patients, mean age 71.5 years divided into two groups: navigated TKA (n=55) and non-navigated TKA (n=50). The same surgeon performed all operations using the same type of implant. We assessed perioperative variables. Clinical and radiological data were analysed pre-operatively then postoperatively with a prospective protocol (2.6 and 12 months) by a single observe. The statistical analysis accepted p< 0.05 as statistically significant.

Results: The two groups were comparable preoperatively regarding age, gender, BMI. Patients in the navigated group had significantly greater persistent flexion (5.32 versus 4.15, p=0.04) and valgus (4.19 versus 3.98, p=0.04) preoperatively. Operative time was measurably but not significantly longer with navigation (90.4 min versus 95.9 min), and was associated with greater blood loss (p=0.02). Intra- and postoperative complications and duration of the hospital stay were similar in the two groups (p> 0.05). The position of the implants was comparable in the two groups (HKA=179±1.58 in the navigation group and 176±3.6 in the non navigation group) with a smaller spread in angle values. At six months, active flexion was significantly better in the non-navigated group (107° versus 101°, p=0.016), but there was no difference in terms of patient satisfaction.

Discussion: Our study was unable to demonstrated any evidence of significant difference between TKA implanted with or without a navigation system. While the navigation system facilitates implant positioning and improves the reproducibility of the operative procedure, the difference is not significant in the hands of an experienced surgeon. Conversely, use of the navigation system, at least during the learning curve, has been associated with longer operative time and greater blood loss. For major deformities however, the navigation technique facilitates reconstruction of the knee joint.


Hervé Hourlier François Marié Peter Fennema Nicolas Reina Michel De Lestang

Purpose of the study: Conventional techniques for implantation of a TKA allow a neutral mechanical axis (HKA 180±3) in 70 to 86% of patients. The purpose of this work was to evaluate the contribution of intraoperative radiologic assistance for this objective.

Material and methods: We conducted a prospective randomised study in a single-operator consecutive series of cemented TKA, model TC-SB, excluding revisions and frontal deviations > 25. The series included 65 women and 39 men, mean age 73 years. All operations were performed on a radiolucent table. An extramedullary guide was used for the tibial cut and an intramedullary guide for the femoral cup. Patient randomisation was done after the cuts. According to the randomisation, the orientation of the cuts in the frontal plane was measured radiographically using a fluoroscope and an aiming plate situated on the hip, then the ankle. Secondary cuts were made if the angular deviation was greater than 1°. The position of the TKA assisted by the fluoroscope (group R+, n=52) and that of the non-assisted TKA (group R-, n=52) was assessed on the digitalised goniometry.

Results: Mean operative time was 70 minutes in group R+ and 59 minutes in group R-. In group R+, the mean mechanical alignment was 3.9 varus preoperatively and 0.13 valgus postoperatively (5 valgus to 3 varus) with 91% in the ±3 range. In group R-, the mean mechanical alignment was 6.7 varus preoperatively and 0.06 varus postoperatively (6 varus to 5 valgus) with 80% of the cases in the ±3 range. The standard deviation was 2 in group R+ and 2.7 in group R-, with no significant difference.

Discussion: The accuracy of the implantation obtained with the conventional instrumentation for the TC-SB prosthesis is among the best reported in the literature. Intraoperative radiological assistance enabled a tighter spread of the results around the mechanical alignment. The technique was simple to use and precise. The mean duration of exposure to the fluoroscope was 3 s (PDS 3 – 35 gray cm2).

Conclusion: We reserve this assistance in priority for patients with major bone deformities or medullary obstacles.


Adrian Ioncu David Dejour P.J. Ternamian Nicola Bonin

Purpose of the study: Grafting the anterior cruciate ligament with a bone-tendon-bone free transplant injures the harvesting site, causing sensorial disorders by injuring the infrapatellar nerve in 70% of the cases. Mini-invasive techniques can limit these complications. The purpose of this work was to analyse the feasibility of a mini-invasive technique using a single incision.

Material and methods: A prospective comparative study was conducted in our unit to compare a group of “classical” harvesting via an anteromedial incision and a “mini-invasive” technique using a incision centred on the patella with the graft being harvested with a specially designed harvesting instrument. Each group was composed of 20 patients. The patients were reviewed six to eight months postoperatively. Clinical assessment (IKDC, Lillois score, analysis of sensorial impairment) was associated with the radiographic and ultrasound analysis. Radiographic laxity was assessed on the stress views at 15 kg. The ultrasound study analysed the patellar tendon and the peritendon. Significance for statistical tests was set at 0.05 with correlation coefficients (R) determined with a covariance matrix ½ Log([1 + R]/[1−R]).

Results: The grafts harvested by the classical method presented good characteristics in all cases whereas this was true for only 45% of the mini-invasive grafts. Anterior pain was noted in 22% of patients in the classical group and in 33 of the mini-invasive group. There was no correlation between anterior knee pain and knee walking or thickness of the peritendon. A correlation was found between knee walking and asymmetry of the patellar tendon thickness in the mini-invasive group. The subjective IKDC score was the same in the two groups and the IKDC objective score was not significantly different (94% (A or B) in the classic group and 81% (A or B) in the mini-invasive group.

Conclusion: This mini-invasive technique with a single incision respects the infrapatellar branches of the medial saphenous nerve in 95% of the cases. But the quality of the graft is less satisfactory than with the classical harvesting technique. A correlation was found between the form of the anterior tibial tubercle which could be used to better define the ideal indication for this technique which remains a difficult procedure.


Ibrahim Kalouche César Vincent-Mansour Marc Soubeyrand Véronique Molina Charles Court Olivier Gagey

Purpose of the study: Different posterior osteosynthesis techniques have been described for the treatment of unstable injury of the pelvic girdle. Bi-iliac fixation using threaded rods or plate-screw fixation has been proposed. The purpose of this work was to describe a modification of the posterior osteosynthesis using instrumentation designed for the spinal column.

Material and methods: From January 2006 to October 2008, four patients (three men, one woman, mean age 24 years, range 18–34) underwent surgery in our unit for unstable fractures of the pelvis with a trans-sacral posterior fracture line (AO classification C1.3–4). Two patients presented neurological signs including one by head trauma with hemiplegia. Two patients had an anterior fixation with an external fixator and another an anterior plate fixation. The operation was conducted via a posterior midline incision. After reduction of the fracture, the osteosynthesis was achieved with two poly-axial screws inserted in each of the iliac wings and connected by two rods and one or two cross connectors.

Results: Mean follow-up was 7.5 months (range 5–17). None of the patients developed infectious, neurological or mechanical complications postoperatively. Complete pain-free weight-bearing and walking were achieved in patients at three months. None of the patients had a horizontal or vertical misalignment callus measuring more than 5 mm. Screw analysis showed that three screws penetrated the sacroiliac joint in the first patient of the series with no clinical consequence.

Discussion: This posterior fixation technique for unstable fractures of the pelvis appears to be reliable and reproducible for type C fractures in combination with anterior fixation. It uses standard instrumentation for spinal osteosynthesis. A study with a larger population and longer follow-up is needed.


Florence Aim Florence Aïm Frédéric Zadegan Damien Pourreyron Benjamin Guenoun Didier Hannouche Rémy Nizard

Purpose of the study: TKA on genu valgum raises serious problems for the ligament balance. Excessive release of the lateral retracted ligaments exposes the knee to potential instability in the frontal plane. To resolve this problem and avoid implantation of a constrained TKA, we opted for osteotomy of the lateral condyle removing the insertion of the lateral collateral ligament and the popliteal muscle after release of the fascia lata. The purpose of our study was to evaluate the functional and radiographic outcomes of these patients.

Material and methods: This was a retrospective study from 2002 to 2006. All patients with degenerative joint disease of the knee with severe and/or fixed genu valgum were included. These patients were implanted with a navigated posterostabilised Wallaby TKA (Navitrack) associated with osteotomy of the lateral condyle fixed with screws after acquisition of the ligament balance. The diagnosis and surgical history were noted. The preoperative alignement was determined on the full limb x-ray and from navigation data. The following variables were reviewed: polyethylene height, lowering of the lateral condyle, blood loss, operative time. The postoperative alignment was established at least one year after surgery. Intraoperative, postoperative and late complications were noted. The Knee Society function scores were used.

Results: Fifteen patients, mean age 70 years were reviewed at mean 35 months. The mean duration of the operative time was 136 min with mean blood loss of 620 ml. The mean PE height was 13 mm. All operated knees were corrected with mean alignment improving from 17.71 to 1.5 valgus postoperatively. The function score improved from 35 preoperatively to 79 at last follow-up. There were no cases of patellar instability or secondary laxity. Two patients developed late reflex dystrophy. The only case of revision concerned one non-union of the lateral condyle (screw removed at four months) but had a function score of 85 at last follow-up.

Discussion: Performing an osteotomy of the lateral condyle in complement with the navigated posterostabilised TKA for fixed genu valgum enabled good relaxation and satisfactory functional results so that totally constrained implants can be avoided.


Alexandre Mouttet Philippe Calas Valérie Sourdet

Purpose of the study: Total knee arthroplasty (TKA) is considered to be an effective treatment for degenerative knee joint disease when the functional impairment and the pain fail to respond to medical treatment. The success of TKA is determined by the degree of pain relief, functional recovery, and implant survival. For many years, those advocating or not preservation of the posterior cruciate ligament (PCL) have animated lively debates. Although a consensus has not been reached, posterior stabilised prostheses and prostheses with a mobile plateau are commonly implanted. The purpose of our study was to compare the outcomes obtained with fixed plateau TKA with preservation of the PCL with those obtained with other prostheses with or without sacrifice of the PCL with a fixed or mobile plateau.

Material and methods: This was a prospective study in a single centre including a homogenous consecutive series of 12 TKA (cemented EUROP) with a fixed plateau and preservation of the PCL implanted from 1994 to 1996 in 117 patients aged 73 years on average. The International Knee Society scores were used for the clinical and radiographic assessment at ten years.

Results: At ten years follow-up, 23 patients had died, 14 were lost to follow-up and 80 (82 knees) were evaluated clinically and 43 (45 knees) radiographically. The IKS knee score varied from 31 points (0–60) preoperatively to 88 points (30–98) postoperatively at last follow-up. The IKS function score was 40 points (0–90) preoperatively and 80 (25–100) at last follow-up. Lucent lines were noted for 59% of the condyles and 60% of the tibial plateaus. The lucencies were mainly located in the anterior and posterior zones of the femur (zones 1 and 4) and medially on the tibia (zones 1 and2). Two prostheses were revised at 8 and 11 years for loosening. The overall survival was 98.8% at ten years using the Kaplan-Meier method.

Discussion: The clinical and radiological outcomes of prostheses with fixed plateaus and preserving the PCL in our series with one revision at 10 years were very satisfactory. Our results are comparable with earlier reports in the literature with or without sacrifice of the PCL with a fixed or mobile plateau.

Conclusion: Longer term follow-up will be needed to confirm these results beyond ten years.


Étienne Hoffmann Brice Illhareborde Thibaut Lenoir Cyril Dauzac Moussalam Katabi Damien Breitel Mourad Ould-Slimane Pierre Guigui

Generally, the sacroiliac joint is not considered accessible for arthroscopy under physiological conditions. The non-injured joint is not large enough for introduction of even the smallest arthroscope into the joint space. After traumatic injury however, or in the event of an inflammatory condition or tumour formation, it is theoretically possible to position an endoscope in the joint space. Study of the anatomy of the sacroiliac joint and knowledge of the anatomic relations, particularly the vascular and nervous relations, is a prerequisite for arthroscopic exploration of the sacroiliac joint space. The posterior approach must account for the bone configuration of the iliac wing and the orientation of the sacroiliac joint line. A cadaver study confirmed the feasibility of endoscopic exploration of the sacroiliac joint via a posterior percutaneous access. Based on this anatomic experience, we positioned an arthroscope in an injured sacroiliac joint and report the different phases. A technique for obtaining a biopsy of the anterior aspect under endoscopic control has already been described, but to our knowledge, there is no arthroscopic description of the sacroiliac joint via a posterior access. Indications for arthroscopy of the sacroiliac joint remain very limited. This technique can be used to remove osteocartilaginous fragments or foreign bodies incarcerated in the joint and to obtain biopsy material, drain collections and, in the near future, should allow avivement of the cartilage surfaces with the objective of a percutaneous arthrodesis.


Héléna Bourezgui Xavier Hemery Laurent Barresi Alain Harisboure Émile Dehoux

Purpose of the study: Total knee arthroplasty (TKA) is associated with important intra- and postoperative bleeding often requiring transfusions, leading to certain risks despite classical methods of haemostasis. The purpose of this study was to estimate the efficacy of a fibrin glue for reducing postoperative blood loss after TKA.

Material and methods: This was a single centre single operator randomised prospective study. Two groups of patients received a first-intention TKA implanted without cement. For a control group (n=24) classical surgical haemostasis was performed; in another group of 22 patients, 4 ml of fibrin glue were vaporised on the internal structures and the subcutaneous tissue intraoperatively, just after insertion of the implants and associated with classical haemostasis. In all cases, the patients had gravity drainage for 48 h; the tourniquet was not removed before dressing. All patients had preventive anticoagulation postoperatively on day 1.

Results: Blood loss was calculated from d−1 to d+4 and was expressed in grams and in percentage in order to overcome the bias of body weight and gender. Mean blood loss was 17 g in the fibrin glue group (raw data) or 24% of the blood mass while it was 211 g in the control group, i.e. 31%. The percentage of blood loss was 31 and 24% with fibrin (p=0.05). Three of 22 patients, 13%, required transfusion in the fibrin glue group versus 11 of 24, 46%, in the control group. We did not take into consideration the rate of seroconversion at three and six months postoperatively.

Conclusion: Use of a fibrin glue can significantly reduce the need for transfusion and reduce blood loss postoperatively after first-intention unilateral uncemented TKA.


Emmanuel Soucanye de Landevoisin Antoine Bertani Phillipe Candoni Bastien Orsini Christophe Drouin Éric Demortière

Purpose of the study: The constantly increasing incidence of extracapsular fractures of the proximal femur are a public health concern. The basic therapeutic options are screw-plate fixation and proximal reconstruction with nails. The purpose of this retrospective study was to assess the mid-term results with a new osteosynthesis material, the proximal femoral nail antirotation (PFN-A®) which has a spiral blade.

Material and methods: One hundred eight 108 PNF-A® performed from January 2007 to July 2008 were included in a retrospective clinical and radiographic study. These series included exclusively extracapsular fractures of the proximal femur in subjects aged over 70 years. All patients were assessed with the Parker score pre- and postoperatively. Blood loos, position of the spiral blade on the AP and laterals views and operative time were analysed. We searched for complications (femoral head slide, blade protrusion, head rotation, non-union, fracture on material, and operative site infection). We searched for risk factors.

Results: One hundred eight patients (94% ASA 2 or 3) were reviewed at mean 5.3 months (±1.5). None of the patients were lost to follow-up. At revision, 19 patients had died (17.6%). The mean Parker score declined 1.4 points. All fractures healed at mean 10.4 weeks (±0.6). Six complications were noted: three operative site infections, three head slidings, one intraacetabular protrusion. No statistically significant could be identified. Nevertheless, the three cases with femoral head sliding occurred on fractures that were unstable (type 31-A2) which had a malpositioned blade.

Discussion: There appears to be a consensus on the treatment of proximal fractures of the femur: screw-plate fixation for stable fractures, centromedullary nailing for the others. Arthroplasty is a second-line solution. There are few publications on the new spiral blade of the PFN-A®. This method spares bone stock and allows compaction of the cancellous bone, particularly adapted for osteoporotic bone: the efficacy is comparable with reference techniques with lower rates of sliding (2.%) and acetabular protrusion (< 1%).


Antoine Serre Daniel Lepage Grégoire Leclerc Laurent Obert Patrick Garbuio

Purpose of the study: The purpose of this work was to analyse the respective complications of nail fixations for trochanteric fractures. Since January 2005, we have used the Gamma3™ and the PFN-A™ in routine practice. These nails have evolved and we wanted to compare the latest generation models.

Material and methods: This was a prospective consecutive series of 426 files in a single centre (January 2005 to October 200) reviewed at mean 19 months (3–36 months). All patients with a fracture of the trochanter treated by osteosynthesis were included. Eight senior operators implanted Gamma3™ nails (4 operators) or PFN-A™ nails (4 operators). During this period, 236 Gamma3™ and 190 short PNF-A™ nails were implanted. The two cohorts were statistically comparable regarding: mean age, body weight, ASA score, preoperative autonomy, repair of fracture type.

Results: There was no significant difference between the two implants for: implant position (correct position for 80%), early mortality (5.5%), rate of sepsis (1.6%), which were comparable with the literature. In these two groups, the operative time was shorter than in the literature with an advantage for the PFN-A™ (40 min versus 35 min). Sliding was minimal (1.3% for Gamma3™ versus 1.1% for PFN-A™), as was revision (5.1% versus 4.7%). Conversely, the technical complications were implant dependent: defective automatic distal locking for the Gamma3™ (n=24, 10.2%) with fracture on nail for four patients, and protrusion of the cephalic blade for the PFN-A™ (n=11, 5.8%) due to insufficient impaction and to back glide after excessive distraction followed by impaction.

Discussion: There is a rich body of knowledge on the different nail and screw-plate models. Mean sliding is to the order of 4% and mean revision about 8–9%. We could not find a study comparing the new implant generations. These implants enable a reduction of the general complications for trochanteric surgery, but to ensure persistent results, care must be taken for the distal locking of the Gamma3™ and the intraoperative protrusion of the PFN-A™ blade.


Sophie Abrassart Robin Peter Richard Stern

Purpose of the study: These fractures, and the patients, are generally unstable. Mortality associated with these fractures remains high. It is mainly due to the haemorrhagic risk of the presacral venous plexus and the iliac system. Different techniques have been described to control the haemorrhage: pelvic girdle, embolisation, ligature of the iliac arteries, pelvic packing, pelvis clamp or external fixator. Our objective was to analyse our series of fractures of this type in order to optimise patient outcome.

Material and methods: A prospective study was undertaken from January 2003 to December 2006. Among 450 multiple injury patients, 68 presented an unstable fracture of the pelvis, type B or C. The 38 patients included in this series were haemodynamically unstable. The mean ISS for these patients was 53, mean age 38.6 years (range 24–51). Fractures were diagnosed on plain x-rays of the pelvis, ap view, completed by a total body scan.

Results: All patients were victims of high-energy traffic accidents and were managed using the ATLS protocol. Five patients died early despite intensive care. The patients were divided into three groups: group X: 19 patients treated with a first-intention external fixator, with or without arteriography, 18 patients survived, 94%; group Y: 8 patients treated with a first-intention external fixator with arteriography and followed by laparotomy, 7 patients survived, 87%; group Z: 6 patients had laparotomy without an external fixator, 6 patients died, 100% mortality.

Conclusion: In our experience, the best way to control bleeding associated with unstable fractures of the pelvis is as follows: pelvic girdle at the scene of the accident to the emergency room, emergency external fixation followed by laparotomy if the ultrasound is positive. False positives occur due to suffusion of the retroperitoneal haematoma. Emergency laparotomy without prior external fixation of the pelvis lead to 100% mortality in our series. Similarly pelvic packing or the retroperitoneal approach cannot be proposed without exploration.


Jean-Marc Buord Sébastien Parratte Xavier Flécher Vanessa Pauly Jean-Noël Argenson

Purpose of the study: Three-screw fixation is the classical treatment for true Garden I in the elderly patient. Complication rates have been high in the literature. Furthermore, in this context outcome for arthroplasty after failed osteosynthesis is less satisfactory than first-intention arthroplasty. This is why functional treatment of Garden I fractures of the neck of the femur has been proposed, including rapid return to the upright position and strict radiographic and clinical control. The purpose of this work was to first evaluate the results of this management option for true Garden I fractures in patients aged over 65 years and second to search for factors predictive of secondary displacement.

Material and methods: All patients aged over 65 years and admitted to the unit for true Garden I fractures from January 2005 to December 2006 were included in this prospective study. A functional treatment including early return to the upright position and walking test on day 1 was instituted, followed by radiographic controls on days 2, 7, 14, 21, and 45 then at 3 months and one year. Referral to a rehabilitation centre at discharge on day 5 was scheduled if there was no displacement. In the event of a displacement, arthroplasty was performed. Fifty-seven patients, mean age 82.8±8.5 years (range 65–99) were included. The radiographic and clinical follow-ups were made by an independent observer.

Results: The displacement rate was 29.8%. These patients were treated by arthroplasty. In the group of patients without displacement, at minimum one year follow-up, there has been no need for surgical revision excepting one case of osteonecrosis at one year requiring implantation of a total prosthesis. The mean Parker score in this group was 6.4 and the mean Harris score 83, it was 85 in the arthroplasty group. Among the predictive factors identified at multivariate analysis were: age, gender, side, type of fracture, fracture orientation, degree of valgus or sagittal displacement, general status. Displacement was not statistically predictive.

Discussion: The results of our prospective study show that 70% of patients included were treated successfully without surgery, confirming reports in the literature and justifying utilisation of this management strategy.


François-Laurent Marty Amélie Legouge Philippe Rosset Philippe Burdin

Purpose of the study: Osteosynthesis material adapted to a mini-invasive approach certainly reduces surgical trauma. The purpose of this work was to establish the osteosynthesis equivalence for pertrochanteric fractures using a dynamic hip screw, inserted according to the conventional technique versus a mini-invasive screw system (MISS), in terms of healing without loss of reduction.

Material and methods: This was a prospective pilot study in a single centre. From May 2006 to April 2007, 78 patients (mean age 83 years, 70% women) were included (38 MISS, 40 DHS). There was one exclusion criteria: poor reduction on the orthopaedic table before incision. Radiographic and clinical follow-up for six months. The main outcome was the quality of the reduction and healing at three months.

Results: Eight patients were lost to follow-up and two had died at three months. The two groups were comparable regarding mean age, ASA, fracture type, operator experience, and centring of the head screw. In the MISS group, there was a 20% reduction in blood loss, a shorter incision (9 cm) and shorter operative time (16 min). The differences were not significant. The healing rate without loss of reduction at three months was the same in both groups: 82%. There were three revisions in the MISS group: one infection and two material disassemblies. This problem disappeared with the addition of a locking screw on the nail. There were no revisions for haematoma.

Discussion: There were several biases. The series was not really randomised because the type of material used depended on the availability of the instrument sets. The MISS implant evolved during the course of the study. The operators were more familiar with the DHS. Inclusion criteria were too restrictive. Multiple-injury patients with bleeding had a false impact on blood loss data. None of the differences were statistically significant. Revision for infection was not directly attributable to the material. Nail locking never failed after use of the locking screw.

Conclusion: The main outcome was validated: the healing rate without reduction at three months is equivalent with the two methods (82%). A multicentric study should be conducted to confirm that the mini-incision and the MISS reduces blood loss. It could be expected that this mini-invasive approach will become the rule for osteosynthesis of these fractures with a dynamic hip screw.


Matthieu Ehlinger Philippe Adam David Delpin Thomas Moser François Bonnomet

Purpose of the study: We report a prospective consecutive series of femoral fractures on prosthesis. The goal was to evaluate mid-term outcome of treatment with a locking plate.

Material and methods: From June 2002 to December 2007, we treated 35 patients (1 bilateral), 28 female and 7 male, with a fracture around their total hip arthroplasty (n=21), total knee arthroplasty n=7), unicompartmental knee prosthesis (n=1), between a THA and a TKA (n=2), or between a trochanteric osteosynthesis and a TKA (n=5). Mean age was 76 years (39–93). For the majority, osteosynthesis was achieved via a mini-invasive incision, using a locking plat (Synthes®) bridging the implant in situ. The rehabilitation protocol consisted in immediate weight-bearing for most of the cases.

Results: At revision, one patient was lost to follow-up, one was an early failure, and seven patients had died, including four which were retained for the analysis because data was available for 24, 40, 43 and 67 months respectively. The analysis thus included 30 patients with 31 fractures and mean 26 months follow-up (range 6 – 67 months). The following results were obtained for the initial series: mini-invasive surgery (n=26), access to fracture focus (n=10), total postoperative weight bearing (n=20), partial weight bearing at 20 kg (n=3), no weight-bearing for six weeks (n=13). Complications were: infection (n=2), general (n=2), disassembly (n=3, one femoral stem replacement and two revision ostheosynthesis). Bone healing was obtained in all cases except one. There was a misalignment > 5 in five cases. At review, there was no implant loosening.

Discussion: This work shows that locking compression plates inserted via a mini-invasive approach followed by weight-bearing is a feasible option. This technique combines the principles of closed osteosynthesis with preservation of the haematoma and stability of osteosynthesis material. The rehabilitation protocol was developed in consideration of the nature of the material. The locked plate acts like an internal fixator, allowing increased implant stability. Screw hold appeared to be sufficient to allow early weight-bearing.

Conclusion: Use of locking compression plates for femoral fractures on osteosynthesis implants is effective. The stability of the assembly allow, despite the age of the patients, early weight-bearing and walking, with a stable outcome over time.


Noureddine Bahri Hector Cabreras-Palacios Martin Wurm Maximilian Faschingbauer Arndt-Peter Schulz

Purpose of the study: Implants with multidirectional locking screws theoretically have many advantages for the treatment of periprosthetic fractures. In the event of osteoporotic bone, this system of plate fixation ensures stability and better bone fixation. Using screws anchored in the different angles, we proposed rigid fixation around the prosthesis. We conducted a retrospective analysis of outcomes obtained after treatment of perprosthetic femoral fractures, Vancouver B1 and C, comparing two types of implants with angular stability (straight plate and folded plate).

Material and methods: From June 1999 to December 2007, we treated 58 patients with periprothetic fractures of the femur using locking plates. Mean age was 72.4 years, 40 patients were female. Thirty-two patients (55.2%) had a total hip prosthesis, 21 a total knee prosthesis and 5 both types of prosthesis (8.6%). We noted: peri- and postoperative complications, degree of bone healing, degree of mobility (Barthel Mobility index and stand up and go test) as well as the social status of the patients.

Results: Bone healing was obtained in 56 cases (96.5%). In two patients, the implant was dislocated and in four others there were general complications. The mean time necessary to obtain total weight-bearing two-leg stance was 8.6 weeks. Forty-six patients (78%) had the same social status as before the fracture. For mobility, 52 patients (89%) achieved the same level as before fracture. Four other patients required a crutch for walking and two needed a walker. Mean Barthel index was 85 points (max 100) and improved 35 points at onset of rehabilitation. Mean stand up and go was 22 s.

Conclusion: According to the review of the literature, 35% of plates dislocate after osteosynthesis of periprosthetic fractures. In our study, the rate was 3.5%, with 7% general complications. We can thus conclude that the methods presented here enable good bone healing in the majority of cases.


Antoine Serre Aurélien Couesmes Nicolas Gasse Sonia Huard Laurent Obert Patrick Garbuio

Purpose of the study: Since the advent of locked centromedullary nailing, manufacturers have produced long nails with automatic distal locking systems. Astute instrumentations have been developed to achieve highly stable assemblies. But during insertion, the exact shape o the nail may change adapting to the anatomy of the medullary canal. We wanted to test a new automatic distal locking system: Surelock.

Material and methods: We conducted a preliminary monocentric prospective study over a one-month period where we included all cases of reconstruction of the proximal femur using a long nail. The Surelock system was applied systematically. The amplifier was needed to adjust the insertion device, the amplifier and the nail in the same plane. This configuration required manipulation of the amplifier in a single plane. The operator then had to correct the position of the insertion devise in accordance with the deformation of the inserted nail. It is noteworthy that with this system, the operator’s hands are never in the amplifier field. We measured the time required to achieve distal locking and the time of scopy, as well as any complications.

Results: During this period, ten patients had osteosynthesis with a long reconstruction nail. The epidemiological data were common for this type of condition. Mean time for the distal locking was 11 min (7–15) with a mean 17 s of scopy (2–24). In all cases, the two distal screws were inserted. The automatic locking was correct in 9 of 10 cases. The one failure was the second case in our series.

Discussion: In 2006, Whatling concluded a review of the literature on different means for distal locking that the search should continue for an ideal method and that by far the most widely used method was manual locking. The new method presented here for automatic distal locking allows implantation of two distal safety screws. The main benefit is for the surgeon and the manipulator of the amplifier. Radiation of the surgeon is nearly zero (the surgeon remains outside the amplifier field) and the manipulation to position the amplifier is simplified.

Conclusion: We believe that this technique could be used in routine practice and that this method could be proposed for the entire range of nailing procedures.


Nicolas Lefèvre Serge Herman

Background: Paralysis of the crural nerve secondary to a compressive haematoma of the psoas in the pelvis is a well-known complication of anticoagulant therapy. This complication has also been described after hip or pelvic surgery. Its occurrence in a context of trauma is exceptional.

Case report: A 16-year-old female adolescent sought emergency care for total deficit of knee extension. The patient had an enlarged painful knee subsequent to a skateboard fall. She reported knee trauma involving the patella and a direct shock to the homolateral hip, on the trochanter. Physical examination confirmed the knee and hip pain. Rest was advised. One and a half month after the accident, the patient again consulted for total deficit of active knee extension. The initial diagnosis suggested was posttraumatic rupture of the patellar tendon. An emergency MRI was normal, ruling out this diagnosis. More attentive physical examination revealed the presence of a complete paralysis of the quadriceps muscle by crural nerve palsy. MRI of the pelvic region revealed the presence of a voluminous haematoma of the psoas compressing the crural nerve. Emergency evacuation of the haematoma was performed. The patient underwent rehabilitation for one year and achieved progressive and complete recovery of the quadriceps function. An electromyogram obtained at one year was normal.

Conclusion: This was an exceptional case of crural nerve palsy secondary to a posttraumatic haematoma of the psoas, with no notion of anticoagulation therapy. The initial knee injury was misinterpreted as involving a local patellar problem but in reality had caused a paralysis of the quadriceps muscle. MRI provided the diagnosis of psoas haematoma.


Laurent Galois Christel Cournil-Henrionnet Céline Huselstein Didier Mainard Danièle Bensoussan Jean-François Stoltz Patrick Netter Pierre Gillet Astrid Watrin-Pinzano

Purpose of the study: Monolayer cultures of chondrocytes multiply and rapidly lose their chondrocyte phenotype, limiting their potential for tissue engineering. Mesenchymatous stem cells can preserve their phenotypic characteristics after several monolayer passages, offering a promising alternative for cartilage repair. The purpose of this work was to study the influence of transforming growth factor beta-1 (TGF-beta1) and bone morphogenic protein-2 (BMP2) and/or culture supplements (hyaluronic acid) on matrix synthesis and chondrocyte differentiation of human mesenchymatous stem cells (MSC) cultured on collagen sponges.

Material and methods: MSC were isolated from bone marrow harvested during hip arthroplsty. At the third passage in monolayer culture, the MSC were reseeded on collagen sponges and cultured in vitro for 28 days under seven differ conditions: insulin transferrin selenium (ITS), foetal calf serum (FCS), ITS+TGFbeta1, ITS+ hyaluronate, ITS+TGFbeta1+hyaluronate, ITS+TGFbeta1+BMP2, ITS +TGFbeta1+BMP2+hyaluronate. The phenotypic evolution was followed using the expression of different genes of interest with PCRq (collagen2, collagen1, collagen3, collagen10, agrecanne, versicanne, COMP, Sox9). Synthesis of matrix material was assessed histologically and immunohistochemically.

Results: Used alone, hyaluronic acid did not trigger chondrocyte differentiation of MSC. For the additives FCS, ITS, or hyaluronate, the synthesis of matrix material in the sponge was weak and poor in major constituents of cartilage. Conversely, the other conditions in presence of TGFbeta1±BMP2 induced important expression of collagen2, agrecanne and COMP as well as increased matrix synthesis with a strong content in proteoglycans and collagen.

Discussion: The usefulness of MSC is growing due to their pluripotent characteristics. The conditions leading to their differentiation into the chondrocyte phenotype remains a subject of discussion. Our results show the particular importance of TGFbeta1 in the process of differentiation.

Conclusion: Chondrogenic differentiation of MSC cultured in collagen sponges as well as the synthesis of the cartilaginous matrix requires the presence of TGFbeta1 in the culture medium and to a lesser extent BMP2. These results suggest the perspective of using MSC for guided cell therapy targeting cartilage.


Valérie Lesaichot Frédéric Sailhan Dimitri Leperlier Véronique Viateau Hervé Petite

Purpose of the study: The process of bone lengthening involves three phases: a latence period, distraction, then healing. The healing phase required stability maintained by an external fixator (EF) for 1.16 months/cm lengthening. This time exposes the patient to serious complications. The objective is to accelerate the healing phase in order to shorten the time the patient has to wear the EF. The effect of BMP on osteogenesis in distraction remains a controversial issue. This work was conducted to evaluate the benefit provided by rhBMP-2 for healing the regenerate bone after distraction.

Material and methods: Thirty-nine subadult male rabbits were selected at random. On day 0, a tibial osteotomy was performed followed by installation of a M101 EF. After the latency period of seven days, the distraction began at the rate of 0.5mm/12 h for 21 days. At day 28, at the end of distraction, a new operation was performed and three groups of 13 individuals were created at random. The first group received no material, the second a collagen type 1 sponge, and the third group a collagen type 1 sponge soaked in 100 μg/kg rhBMP-2. The animals were monitored with x-rays, absorptiometry and ultrasound for the qualitative and quantitative analysis. Histological and biomechanical analyses were performed at two months.

Results: Our complication rate was 41%. Qualitative analysis of the x-rays showed, in group 3, the development of more or less voluminous and dense, sometimes hypertrophic calluses. The progression curves of the bone mineral content showed higher values in group 3. The bone mineral content curves remained nevertheless parallel for the three groups. The calluses were thus denser in group 3 but with an early peak density. Groups 1 and 2 had equivalent radiographic and absorptiometric results. The statistical analysis of the imaging findings is ongoing. The histology and biomechanical exams are being performed.

Discussion: The preliminary results show that rhBMP-2 used early in the healing phase enables formation of more dense and hypertrophic calluses. rhBMP-2 does not acceleration the rate of callus formation but stimulates its mineralization. Use of a collagen sponge alone had no effect on healing. Analysis of the histological and mechanic properties observed in the three groups will provide a more precise description of the hypertrophic and strongly mineralized calluses.

Conclusion: Our early results show superior bone mineralization in the treated group.


Frédéric Sailhan Baptiste Gleyzole Roger Parot Henri Guerini Éric Viguier

Purpose of the study: Little work has been reported on the effects of BMP on bone healing after distraction and the data available in the literature are contradictory. The type of BMP as well as the optimal dose remain to be defined. We present the results and complications linked with the use of different doses of rhBMP-2 in a model of osteogenesis in distraction.

Material and methods: Fifteen subadult New Zealand rabbits were selected at random and divided into three groups. On day 0, a mediodiaphyseal tibial osteotomy was cut and an M103 fixation implanted. In group I (5 rabbits), 750μg of rhBMP-2 with a type I collagen sponge (Inductos, Medtronic) were deposited on the osteotomy site. In group II (5 rabbits), 350 μg were deposited on the collagen sponge and in group III (controls, 5 rabbits), nothing was deposited. After the 7-day latency period, distraction was conducted for 21 days (0.5 mm(12hr). At the second week of distraction, the callus was analysed on the x-rays and ultrasounds and a weekly absorptiometry was obtained. The animals were sacrificed three weeks after healing was confirmed.

Results: Quantitative radiographic assay showed significantly superior grading (Kirker-Head) in groups I and II (p< 0.05) compared with group III. The qualitative analysis showed premature healing of the regenerate preventing completion of the distraction (pin distortion) for 3/5 rabbits in group I and 1/5 in group II. Bone mineral content was superior in groups I and II in all times studied than in group III (p< 0.05). The difference was also significant between groups I and II (p=0.0087) demonstrating an expected dose effect.

Discussion: Premature healing was achieved for the majority of animals in group I, underlining the importance of the dose of BMP used to stimulate bone healing after callotasis. The undesirable effect thus obtained should be taken into account in the clinical context. A dose of 100 μg/kg (350 μg, group III) appears to suffice in this model and defines the upper dose limit. Differed application of the compound (after distraction) should be useful and should be studied.

Conclusion: The dose of rhBMP-2 used to stimulate bone healing is an essential parameter that should be defined for each experimental model. The dose effect of rhBMP-2 is demonstrated in this particular model.


Christophe Chevillotte Robert Trousdale Mir Ali Mark Pagnano Daniel Berry

Purpose of the study: Few data are available concerning the proper management of patients with a periprosthetic fracture of the hip who presents biological signs of inflammation (increased WBC, sedimentation rate, or C-reactive protein). The purpose of this work was to determine the prevalence of elevated biological markers in this type of patient and to determine the reliability of such markers for the diagnosis of periprosthetic infection.

Material and methods: A periprosthetic hip fracture was diagnosed in 204 patients from 2000 to 2006. The WBC count, the sedimentation rate and the serum CRP level were noted at admission to the emergency ward. The diagnosis of infection was confirmed by at least two positive bacteriological samples of tissue biopsy and/or joint fluid collected at surgery. A statistical analysis was conducted to determine the prevalence of elevated biological markers of inflammation, the sensitivity, their specificity and their positive predictive value for deep infection.

Results: Twenty-one patients (11.6%) developed a periprosthetic infection. Among the 204 patients, the WBC count increased in 16.2%, sedimentation rate in 33.3% and CRP in 50.5%. The sensitivity was 24% (WBC), 50% (sedimentation rate) and 83% (CRP). The specificity was 85% (WBC), 69% (sedimentation rate) and 56% (CRP). The positive predictive value was low (18, 21 and 29% respectively).

Discussion: Markers of inflammation are frequently ordered before surgery to search for infection but can be elevated for various reasons. Most often, these markers are elevated because of the patient’s general status and are thus related to other co-morbid conditions and/or reaction to the new fracture. In this population, the WBC count did not contribute to the diagnosis of infection as only 24% of the infected patients had a high count. CRP and sedimentation rate and the WBC count had low positive predictive values.

Conclusion: This study shows that an isolated elevation of biological markers of inflammation in a patient with a periprosthetic fracture is not a good indicator of infection.


Christophe Nich Arnaud Marchadier Laurent Sedel Hervé Petite Moussa Hamadouche

Purpose of the study: Oestrogen depletion leads to osteoclastic hyperactivity and subsequent postmenopausal osteoporosis. Little is known about interactions with bone absorption induced by wear particles from joint bearings. The purpose of this study was to evaluate bone response to polyethylene (PE) particles in a mouse model of oestrogen deficiency.

Material and methods: Particles of PE were implanted in the calvaria of seven non-ovariectomised mice and in seven ovariectomised mice (OVX). Fourteen mice were operated on without implantation of the particles (7 non-OVX and 7 OVX, control groups). The mice were sacrificed at two weeks. The crania were studied under a microscanner and histologically without decalcification.

Results: The microscanner showed that particles of PE induced a significant decrease in bone thickness in non-OVX mice (p=0.04), while the thickness remained unchanged in OVX mice who had received the particles (p=0.40). After implantation of the PE particles, the number of osteoclasts per mm of bone perimeter was 2.84±1.6 in the non-OVX mice and 1.74±1.3 in OVX mice (p=0.004). Compared with controls, the mean loss of bone was 12±10% in the non-OVX mice versus 4.7±0.9%in the OVX mice (p=0.004).

Discussion: The volume of osteolysis induced by PE particles was smaller in OVX mice compared with non-OVX mice.

Conclusion: These results suggest that a deficit in oestrogens has a protective effect against bone adsorption induced by PE particles.


Elhadi Sariali Todd Stewart Zonghmin Jin John Fisher

Purpose of the study: Implantation of the acetabular socket with high inclination generates increased contract stress, wear and revision rate for total hip arthroplasty (THA). Study of ceramic-on-ceramic THA explants has revealed a high wear rate in bands, suggesting a microseparation effect generating edge loading. There have not been any studies examining the influence of the cup inclination on the contact pressures in ceramic-on-ceramic THA exposed to microseparation between the head and the cup.

Material and methods: A finite elements model of a ceramic-on-ceramic hip prosthesis was developed with ABAQUS in order to predict the surface contact and the distribution of the contract pressures, first during ideal centred function then under conditions of microseparation. A 32mm head and a radial clearance head (30μm) were used. The cup was positioned in zero anteversion and 45, 65, 70, and 90° anteversion. Progressive microseparation (0 to 500 μm) was imposed. A 2500N loading force was applied to the centre of the head.

Results: For 45° inclination, edge loading appeared for mediolateral separation greater than 30 μm and became complete for 60 μm separation. When edge loading appeared, the contact surface was elliptic. The length of the lesser axis converged towards 0.96mm; the greater axis towards 8.15mm, respectively in the anteroposterior and mediolateral directions. For inclinations of 45°, the contact pressure was 66 Mpa for the centred force. As the mediolateral separation increased, the maximal contact pressure increased, converging towards an asymptotic value of 205 MPa. Increasing the inclination angle of the cup generated an increase in the maximal contact pressure. However, this increase in contact pressure generated by the increasing inclination angle was negligible if the microseparation increased.

Discussion: Cup inclination and mediolateral laxity increase stress forces of ceramic-on-ceramic THA and should be avoided. However, the influence of the cup inclination becomes negligible beyond a separation value of 240 μm, the stress forces already having reached their asymptotic value.


Ludovic Schneider Antonio Di Marco Patrick Simon

Purpose of the study: Biphasic macroporous phosphocalcium ceramics are used in routine surgery to fill bone defects. This type of material presents the characteristics of an ideal substitute: free of the adverse effects of grafts, biocompatibility, bioactivity, osteoconduction, osteointegration, reproducibility, availability in sufficient quantity. The purpose of our work was to evaluate the role of osteointegration on the resistance of two macroporous biphasic phosphocalcium ceramics routinely proposed on the French market. These two macroprous materials have a similar chemical composition but vary by the presence or not of interpores.

Material and methods: The experimental model involved the implantation of ceramic cylinders in a femoral cortical site in sheep, via the intermediary of conduction chambers with specific cortical entrances. The resistance to compression of the implanted samples an non implanted controls was measured using the same ISO norms.

Results: After two months implantation in a cortical site in the sheep, Eurocer200plus® exhibited a significant 38% increase in resistance to compression while in the same conditions, Triosite® exhibited a 41% decline in resistance. For ceramics with open porosity, the interpores acted like tunnels enabling rapid colonization for osteoforming cells and early formation of new bone reaching the centre of the substitute, and leading to increased material resistance. Cell colonization of a ceramic with closed porosity is, on the contrary, slowed by the partitions, while its dissolution by biological fluids within the micropores occurs in all materials; there results an imbalance between absorption and synthesis, leading to loss of mechanical resistance as a first phase of osteointegration.

Discussion: Open macroposity enables an improvement in the mechanical properties of a biphasic ceramic substitute due to more rapid osteointegration. In the future, material associated with osteoinduction cells or proteins should play an important role, together with changes in the architecture of the ceramic skeleton which should play a determining role in terms of physical and biological properties.


Pedro Domenech Pedro Gutierrez Jesus Burgos

Purpose of the study: Neurophysiological monitoring during pedicular screw insertion has been used to verity bone integrity of instrumented pedicles. The purpose of this study was to determine, experimentally, whether the EMG thresholds after stimulation of dorsal pedicular screws depend on the distance between the nerve structures and the screw, or on the interposition of different tissues.

Material and methods: EMG thresholds were recorded after stimulation of 18 VPD in fivde pigs, by varying the distance between the screws and the spinal cord (2, 6, 10 mm). The thresholds were recorded after rupture of the median pedicular cortical and after interposition of different tissues (blood, muscle, fat and bone) between the screws and the spinal cord. In four patients with a hemivertebra, four pedicular screws sere stimulated at insertion, just after resection of the hemivertebra.

Results: The average intensity of the EMG thresholds was 5.60±1.90mA when the screws were in contact with the dural sac. When the distance was 2 mm, the average threshold reached ±3.42 mA, at 6 mm 13.59±6.27 mA and at 10mm, 15.86±5.83 mA (p< 0.05). Rupture of the median pedicular cortical and interposition of different biological tissues in experimental animals did not modify the stimulation thresholds of the dorsal pedicle screws. In the four operated patients with resection of a hemivertebra, the EMG stimulation thresholds exhibited a wide spread but did not provide any evidence for a significant change related to interposition of different tissues. The impedance of the bone material was higher than muscle or adipose tissue. In these patients, the distance from the screw to the spinal cord was not correlated with a modification in the stimulation threshold.

Discussion: Further clinical study is needed to better understand the stimulation role of the EMG in the implantation of pedicular screws, considering that this technique does not determine pedicle rupture.

Conclusion: In experimental animals, the electrical impedance appears to depend on the distance between the screw and the nerve structures but not on the integrity of the median pedicular cortical. Response to intensity does not appear to be related to the type of interpositioned tissue.


Anthony Viste Julien Chouteau Rodolphe Testa Laurence Chèze Michel-Henri Fessy Bernard Moyen

Purpose of the study: Anteversion of the cup during total hip arthroplasty (THA) is crucial for preventing the risk of dislocation. Interest has recently focused on an anatomic element often observed in the operative field during hip surgery: the transverse acetabular ligament (TAL). The TAL has become a landmark both for conventional procedures (Beverland) and for computed-assisted surgery. The purpose of this original research was to study the anteversion of the TAL in relation to the anterior pelvic plane in order to determine whether it could be a valid landmark for positioning the cup using the Lewinnek criteria (35±20° anteversion according to the Murray definition).

Material and methods: Eight laboratory cadavers (three male, five female, mean age 82±3.3 years) were dissected; the pelvis was removed. Fifteen fresh healthy hips (free of trauma or degenerative disease) were also used for the study. The orientation of the peri-acetabular structures was measured with the probe of the BrainLab® navigation system and the Motion Analysis® system (Santa Rosa. CA) at the laboratory of biomechanics and biomechanical shocks (INRETS, Bron). The Lewinnek reference plane (anterior pelvic plane) was defined from the anterosuperior iliac spines and the pubic tubercles.

Results: The anatomic version of the TAL varied from −8 to +13.3 (mean 1.9); the anatomic version of the horns of the semilunate surface from −12.2 to +14 (mean 3); for the labrum the figures were +17.4 to +41.8 (mean 26.63). Anteversion of the TAL and the horns were well correlated (r=0.8) significantly (p=0.001).

Discussion: There is no other study concerning the anatomic orientation of the TAL, the horns and the labrum. Archbold was the first to consider the TAL (1000 cases, posterolateral access, 28 mm head) as a reliable constant landmark for positioning the cup (0.6% dislocation). In our study, the anatomic version of the TAL was found outside the safety zone of Lewinnek. This is a supplementary argument for questioning the reliability of the Lewinnek criteria based solely on nine cases of dislocation and criticised by several authors (non-specific for each patient).

Conclusion: Anteversion of the labrum is situated within this safety zone. The TAL does not position the cup in the Lewinnek safety zone, which remains controversial.


Arnaud Clavé Florian Boukhechba Thierry Balaguer Georges F. Carle Christophe Trojani Nathalie Rochet

Purpose of the study: The efficacy of a new oestrogeneration biomaterial should be demonstrated by in vivo grafts in animal models. Critical filling of bone defects in the rat could be useful as a model before beginning studies in large animals such as the sheep, goat or dog. Creation of a critical defect in the rat femur has been described, but not standardized, leading to difficult comparison between series. In this work, we wanted to establish a detailed standardisable surgical protocol for the creation of a 6 mm femur defect in the rat.

Material and methods: We compared three anaesthesia protocols using 18 mal Wistar rats aged 21 weeks. We developed a surgical procedure enabling study of the advantages of the different commonly used surgical devices either in research or clinic to achieve osteosynthesis and a 6 mm bone defect. We also compared two types of fixation plates (and screws) available on the marker: a 1.2 mm thick titanium plate used for hand surgery and a 1.5 mm steel plate (veterinary medicine). Our postoperative clinical and radiographic follow-up was designed to validate our operative protocol and evaluate osteoregeneration.

Results: We demonstrated first that the use of multimodal anaesthesia radically improved the clinical outcome in the animals. We then demonstrated that the 1.2 mm titanium plates recommended in other studies were too fragile in our model and that the steel 1.5 mm veterinary plates were more adapted. We finally demonstrated the superiority of surgical devises to create a defect and for osteosynthesis. We described a postoperative protocol offering satisfactory evaluation, clinically and radiographically.

Discussion: This work is the first describing this protocol in detail. Improvements in feasibility and cost will make a readily exploitable model for other laboratories. The follow-up on this work should be aimed at improving the quality and pertinence of the analysis methods for the assessment of bone regeneration.

Conclusion: We propose a mode for the critical defect in rat femur bone as a reliable model for the study of osteogenic capacities of new biomaterials.


Elhadi Sariali Todd Stewart Zonghmin Jin John Fisher

Purpose of the study: Ceramic-on-ceramic THA explants exhibit a higher wear rate than that predicted by classical simulators. This appears to be related to edge loading, which could perhaps be reproducible in vitro by creating a microseparation between the two components. The purpose of this study was to evaluate this coefficient of friction for ceramic-on-ceramic THA with edge loading. This should enable prediction of wear in the event of microseparation.

Material and methods: Three 32mm alumina inserts (Biolox Forte Ceramtec®) were tested on a friction simulatior (Prosim®). The cup was positioned vertically (75° inclination) to reproduce edge loading. The metal-back and the acetabular insert were sectioned to avoid impingement between the neck and cup. Contact was imposed along the border of the cup, then perpendicularly to it. The tests were performed under lubrication conditions (25% bovine serum). In order to simulate severe contact pressures, the tests were also conducted with a third body inserted between the head and the edge of the cup. To obtain reference values of the centred regimen, tests were first run with identical components positioned horizontally.

Results: Edge loading was achieved for cups inclined at 75°. The coefficient of friction was 0.02±0.001 under centred conditions. For edge loading conditions, the coefficient of friction was significantly increased, to a mean 0.09±0.00 for movement along the acetabular border and 0.034±0.001 for movement perpendicular to the border. Squeaking occurred for 15 s when the third body was introduced, corresponding to a coefficient of friction 15-fold higher (0.32±0.003) than under ideal conditions.

Discussion: For the first time, the coefficient of friction of edge loading was determined under conditions of lubrication. The friction coefficient of ceramic-on-ceramic THA was greater for a very vertical cup, but remained (0.1) equivalent to the metal-on-metal coefficient under optimal conditions. When a third body was introduced, transient squeaking occurred with a very high coefficient of friction.

Conclusion: Implantation of cups with a high abduction angle induces edge loading and an increased coefficient of friction, and should be avoided.


Bruno Chemama Eric Bonnet Maryse Archambaud Claudine Cauhépé Anne Brouchet Nicolas Bonnevialle Pierre Mansat Paul Bonnevialle

Purpose of the study: Propionibacterium acnes (PBA) is an anaerobic Gram-positive commensal bacillus of human skin which can cause bone and joint infections (Lutz 2005, Zeller 200, Levy 2008). The purpose of this work was to evaluate over a given period the frequency of PBA infections and the reality of its role as a pathogenic organism.

Material and methods: A retrospective survey of activity from 2006 to 2008 using bacteriology laboratory data identified 34 patients (22 male and 12 female) with at least one sample collected during an orthopaedic or traumatology surgical procedure that was positive for PBA. The mean number of positive samples was 3.6; 17 from the thoracic limb, 17 from the pelvic limb, involving 16 arthroplasties (4 hips, 6 knees, 5 shoulders, 1 elbow), 13 osteosynthesis procedures, 3 cuff repairs and 1 acromioclavicular procedure. Six of 20 histology samples showed a septic granuloma.

Results: The PBA was the only germ isolated in 18 cases; it was associated with other bacteria in 16 cases. Other blood tests were abnormal (WBC 6800 leukocytes, CRP 25mg/L en average). According to the Lutz classification, three groups of infection could be identified: certain infection with clinical signs and at least two positive samples (n=12), possible with clinical signs but only one positive sample (n=5), and probable without clinical signs and one or more positive samples (n=17). Of the 12 patients in the first group, eight had material (three shoulder prostheses, three hips, one knee and one femoral nail), which had to be removed for six with use of a cemented spacer in four. Mean duration of antibiotics was five weeks. Four patients in this group have not yet achieved cure. In the second group, all samples were taken from a thoracic limb and had another germ in four cases; all patients have achieved cure. In the third group, the samples were systematic (two shoulder arthroplasties, two repeated cuff repairs, five revision prostheses, four nonunions and four material removal); only one sample was positive in ten cases and only five patients were given antibiotics; all achieve cure.

Discussion: This series is in agreement with the literature: frequent localization on a thoracic limb, association with another germ, questionable attribution to PBA. Patients meeting the criteria of the first group should be treated. If a PBA infection is suspected, samples should be repeated, with prolonged culture; this attitude should be validated prospectively.


Vincent Pineau Benoit Lebel Solene Gouzy Sébastien Emily Jean-Jacques Dutheil Claude Vielpeau

Purpose of the study: The concept introduced by Gilles Bousquet is an effective arm against dislocation of total hip arthroplasty (THA), as has been demonstrated in clinical series with a long follow-up. There remain certain questions concerning wear of dual mobility cups. We propose a radiostereometrical analysis (RSA) of femoral head migration in this type of implant. Our objective was to establish an accurate measurement and determine the intra- and interobserver variabilities.

Material and methods: A THA model was implanted and loaded with a simulator. Penetration of the implants was measured using a specially designed polyethylene insert with increasingly concentric wear (from 0, 0.25, 0.5 to 0.75 mm). Three investigators analysed (7 times in a double-blind protocol) the RSA images of these four inserts. The investigators were an expert (I), well-trained (II), naive (III). The accuracy of the measurement as well as the intra- and interobserver variabilities were determined using the root mean square (RMS) method, the interclass coefficient of correlation (ICC), the Bland and Altman analyses, and weighted Kappa analysis.

Results: Regarding accuracy, the RMS was 0.0388 [CI95: 0.02266–0.05564]. The mean error for preworn inserts was respectively 0.022mm (for 0.25mm prewear), 0.59mm (for 0.5mm), and 0.022mm (for 0.75mm). The intra-observer ICC was 0.9714 [0.9028–0.9918] for investigator I. The interobserver ICCs between investigators I and II and between I and III were respectively 0.943 and 0.968. The weighted kappa coefficients between I and II and between I and III were 0.827 and 0.849. The Bland and Altman analysis confirmed these results.

Discussion: Several RSA protocols could be designed to measure wear of the dual mobility cup. We chose detection of the wear pattern instead of the tantalum beads method. Our protocol, using a simple geometric model and not the manufacturers CAD files, showed an accuracy comparable with manufacturing tolerances with low variability.

Conclusion: This study validated our measurement method, a prerequisite for a randomized multicentric study which has been initiated to compare, by RSA, penetration of the head into the double mobility insert versus a fixed insert.


Xavier Flécher Pierre Bongrand Emmanuel Rixrath Sylvie Wendling Joana Vitte Jean-Nöel Argenson

Purpose of the study: Because of the growing number of aseptic loosening of total hip arthroplasty (THA), a reliable biological marker would be useful to diagnosis osteolysis early and non-invasively while avoiding the risk of false positives. The purpose of this study was to analyse the value of the interleukin-10(IL10)-alphaTNF ratio in serum and synovial fluid as a marker of THA aseptic loosening.

Material and methods: Blood synovial fluid samples were collected in 27 volunteers with a cemented THA (group THA) and 30 healthy subjects comparable for age and gender who were programmed for total hip arthroplasty because of primary osteoarthritis (group OA). We analysed: locally by the level of alphaTNF and IL10 in the supernate of differentiated THP-1 with and without adjunction of synovial fluid (SF); in the bloodstream the production of alphaTNA and IL10 by monocytes; the correlation between serum and SF levels and the presence or not of loosening.

Results: In the THA group, SF induced a relative decrease in IL10 strangly not associated with an increase in alphaTNF. However, the IL10/alphaTNF ratio was significantly lower in the OA group. Circulating monocytes produced more alphaTNF in the THA group while there was no significant difference in the production of IL10 by the two groups. However, the IL10/alphaTNF ratio was significantly higher (2-fold) in the THA group. Regarding serum cytokine levels, there was a local accumulation of alphaTNF in the THA group and IL10 in the OA group.

Discussion: The IL10/alphaTNF ratio alone was significantly correlated with aseptic loosening, locally and in the general bloodstream. IL10 or alphaTNF did not alone correlate in all conditions. These results show that use of this ratio appears to be more effective than assay of a single proinflammatory cytokine for the early diagnosis of aseptic loosening. The validity of this ratio is supported by its local and general correlation. A comparative prospective study in healthy subjects using a non-invasive method (except for the blood samples) should be conducted to confirm the clinical pertinence of this marker.


Nicolas Bigorre Laurent Hubert Thomas Apard Pascal Bizot

Purpose of the study: Infection is a rare complication of shoulder athroplasty (3% of reverted prostheses), potentially responsive to diverse therapeutic strategies. This work evaluated the clinical and infectious outcomes obtained after management of infectious complications of reverted total shoulder arthroplasty.

Material and methods: This series included 11 reverted shoulder arthroplasties reviewed at mean 39 months. The bacteriological analysis identified predominantly Pro-pionibacterium acnes (54%). Three patients presented an acute infection, five a subacute infection, and three a chronic infection. In this series, six patients underwent a wash-out debridement procedure, two a two-phase reimplantation, and three a one-phase reimplantation.

Results: At last follow-up, three patients died, eight were reviewed. In the wash-out debridement group, one patient developed recurrent infection and two had repeated dislocations; the mean Constant score was 62 points and the ASES score 16/30. In the two-phase reimplantation group, there was no recurrent infection, the spacer broke in one patient, and the mean Constant score was 45 and the ASES score 10/30. In the one-phase reimplantation group, there were no cases of recurrent infection; the mean Constant score was 51 and the ASES score 11.

Discussion: The therapeutic strategy remains a controversial issue for the infected shoulder arthroplasty. Experience with infected knee and hip prostheses is essential. For infected shoulder prostheses, resection was for a long time the advocated solution, allowing cure and pain relief at the cost of major loss of shoulder mobility. Recent series have reported the effect of wash-out, debridement and reimplantation, allowing restoration of function. In the series reported here, the objective was to restore shoulder function as best as possible while achieving cure of the infection.

Conclusion: Although techniques for surgical revision were inspired by experience with the hip and knee, the problems with shoulder infections are different. The unique goal of curing the infection must be revisited. Shoulder function, and in particular range of motion conditioning the functional outcome, should dictate the surgical strategy for these infections.


Guillaume Riouallon Thibaut Lenoir Pierre Guigui

Purpose of the study: Surgical strategy for the treatment of pyogenic spondylodiscitis remains a controversial issue, mainly because of the low incidence. This retrospective review was undertaken to clarify current practices.

Material and methods: Nineteen patients (11 male, 6 female)with pyogenic spondylodiscitis underwent surgery from 2003 to 208. Mean age at surgery was 62.7 years (41–100). The localisation was cervical (n=6), thoracic (n=8) and lumbar (n=3). Motor deficit was present preoperatively in 13 patients. There were no cases of complete paralysis. The indication for surgery was aggravation of the neurological deficit in 14 patients and kyphosic deformity in three. The release was achieved via an anterior access for the cervical cases and via a posterior access for the thoracic and lumbar cases. The circumferential procedure achieved complete bilateral arthrectomy. In all cases the instrumented fusion was followed by postoperative immobilisation for three months. Antibiotics were also given for three months. Functional and radiographic outcome were assessed at last follow-up.

Results: Mean follow-up was months (12–26 months). There were no clinical or biological signs of recurrent infection despite implantation of osteosynthesis material. Irrespective of the delay to treatment, the 13 patients with a preoperative deficit presented signs of recovery. Eight of them recovered completely and the five others had a motor deficit rated at 4/5. Radiographically, there were no fusion failures at last follow-up. Two patients had revision surgery: one for recurrent tetraparesia due to a postoperative epidural haematoma, the other to achieve impaction of the graft in the vertebral body.

Discussion: – This series emphasises the clinical impact of surgical treatment of pyogenic spondylodiscitis. Surgery enables a certain degree of neurological recover achieved by wide decompression. It enables bone fusion despite instrumentation in this complex septic situation.


Anis Ben Lassoued Mhamed Bahri Wajdi Bouallègue Ramzi Boufarés Vladimir Gavrilov

Purpose of the study: Brodie abscess is a purulent collection in the centre of a bone separated in its typical form from soft tissue by an impermeable barrier of compact bone tissue. This “trapped” collection causes a clinical syndrome of pain and infection. Lat diagnosis is frequent after the symptoms have evolved over months or years. The purpose of our work was to illustrate the misleading features of this bone infection using a series of 11 periarticular localisations of Brodie abscess.

Material and methods: Our study included ten patients, mean age 18 years, who were treated over a period of six years. One patient had a double localisation. The main foci were the distal femur (n=4) and the upper tibia (n=4). There was one case involving the lower tibia, on in the olecranon and one in an iliac bone. The clinical course was greater than one year in three patients, and greater than one month in four others. The clinical presentation was a septic arthritis of the knee joint in three patients and of the hip in one, with rupture of the abscess into the soft tissues in three cases and a central intra-osseous collection in four. Biological features of infection were present in all patients. Imaging (x-ray, CT) showed a bone defect in the metaphyseal or metaphyseal epiphyseal region in all cases with condensed contours and a fistulous tract to a joint or soft tissue. Surgical treatment was proposed in all cases to treat the causal lesion by saucerisation and drainage of the intra-osseous abscess. The defect was filled with an autologous graft in one case and by cement in another. The germ identified in 70% of the cases was a Staphylococcus aureus. Adapted antibiotics were delivered for eight weeks on average.

Results: One patient had a secondary fistula which developed early after excision of a central abscess of the proximal tibia; dry drainage was achieved after cover with a medial gastrocnemian flap. At mean 27 months follow-up, all lesions have cured without recurrence; blood tests returned to normal. Radiographically, the defect exhibited bone remodelling visible in the absence of surgical filling. Regarding function, there was one stiff knee due to adherence on the extensor system.

Discussion: The Brodie abscess is a form of chronic osteomyelitis. It is a rare condition generally observed in young subjects since the majority of reported cases have occurred during the second decade of life. Clinically, the Brodie abscess can be “cold” with little or no overt expression, or more readily “hot” with a syndrome of acute infection and fistulisation to soft tissue. Fistulisation to a joint can mislead the diagnosis to septic arthritis as occurred in one of our patients who underwent two revisions for septic recurrent arthritis of the knee. Most Brodie abscesses are located in the metaphysic. A double metaphyseal and epiphyseal localisation through the growth plate is rare, resulting from an old septic process with inevitable joint collection as in one of our patients aged ten years. Discovery of a second concomitant localisation can be explained by an insufficient or inadequate treatment of the initial focus as we also observed in one case. The classical radiographic image of a Brodie abscess is observed in only two-thirds of the cases. Computed tomography is highly contributive demonstrating possible infra-radiographic fistulisation to a joint or soft tissue as occurred in most of our patients. The Brodie abscess can also simulate bone tuberculosis, hydatic cyst, or bone tumour. Surgically, we adopted to therapeutic strategies: excision of the infected bone associated or not with a cancellous graft and per primam closure for cold abscesses. We have considered that cold abscesses are generally cause by germs with weak virulence; this attitude enables avoiding superinfection. The second option is excision with dressing with or without secondary cancellous graft after budding used for hot abscesses, especially when complicated by a soft tissue complication. Search for germs in blood cultures and in the excision produce was only positive in half of our cases. Staphylococcus was identified in 90%. A histology examination of the excision specimen should be systematically requested to confirm the diagnosis. Finally, the outcome of a well-treated Brodie abscess is favourable.

Conclusion: Brodie abscess is a rare condition observed in young subjects generally due to Staphylococcus aureus. Cold and hot abscesses can be differentiated by their clinical and therapeutic features. Often misleading, clinical symptoms can be detailed with modern imaging, particularly important when the radiographic aspect is atypical. A biopsy is indispensable to confirm the diagnosis.


Shahnaz Klouche Elhadi Sariali Philippe Léonard Luc Lhotellier Wilfrid Graff Philippe Leclerc Valérie Zeller Nicole Desplaces Patrick Mamoudy

Purpose of the study: Plurimicrobial infections account for 4 to37% of all infections of total hip arthroplasties (THA). According to data in the literature, they are the source of failure, contraindicating one-phase replacement procedures. The purpose of our study was to evaluate the results of our management practices in this group of patients and also to identify factors of risk associated with multimicrobial infection.

Material and methods: A prospective study included 116 patients with an infected THA from November 2002 to December 2006. Sixteen patients (13.8%), mean age 68±12.7 years had a plurimicrobial infection defined by having at last two interoperative bacteriological samples positive for two or more germs. Surgical treatment consisted in a single-phase replacement in seven cases, a two-phase replacement in seven, resection of the head and neck in one, and wash-out resection in one. Mean duration of the antibiotic therapy ws 91±6 days, including 46±14 days intravenously. Anaerobic germs were isolated more commonly in plurimicrobial infections than monomicrobial infections (50% versus 11%). Patients were assessed with prospectively collected data. Mean follow-up was 34±13 months, with none lost to follow-up. The main outcome was apparent cure rate of the initial infection at minimum two years follow-up, defined by the absence of clinical, biological and radiographic signs of infection, and absence of death attributable to infection or its treatment. If infection was suspected, a hip puncture or intraoperative samples confirmed the relapse (same germs) or reinfection (different germs).

Results: The cure rate was 100% for plurimicrobial infections and 97% for monomicrobial infections. There were however four reinfections in the monomicrobial group. In this series, the risk factor statistically associated with plurimicrobial infections was the presence of a fistula with an odds ratio of 5.4.

Discussion: A larger number of patients would probably enable identification of other risk factors associated with plurimicrobial infections.

Conclusion: The cure rate of plurimicrobial infections was higher than reported in the literature but for a small group of patients. The presence of a fistula was strongly associated with these plurimicrobial infections.


Mohammed Karray Abdelaziz Zarrouk Mohamed Bouabdellah Marouen Amdou Kheriddine Laamouri Skander Kammoun Ridha Sallem Slim Mourali Ramzi Bouzidi Hammadi Lebib Khalil Ezzaouia Mondher Mestiri Mondher Kooli Monji Zlitni

Purpose of the study: Echinococcosis is an anthropozoonosis with a predominantly muscular, more rarely osteoarticular, localisation. The purpose of this work was to describe the conditions of discovery, the diagnostic management, the serology and pathology findings, and the results of surgical treatment as well as potential complications.

Material and methods: We collected over a 16-year period, 14 cysts in eight women and six men. Mean age was 39 years (range 17–75) and delay to consultation was 36 months. The patients had an ultrasound (all 14 cases), computed tomography (n=7), MRI (n=7), hydatid serology (n=9) and pathology examination (n=10). All patients were treated surgically (7 complete resection); one patient was given associated medical treatment for a multiple localisation.

Results: Muscle hydatisosis occurred in all cases as a medium-sized tumour (mean 9 cm, range 5–16 cm) which was painful in half of the cases. One cyst was superinfected and one patient had a neurological complication. The most common site was the adductor compartment of the thigh (5 cases). Four patients had an associated visceral localization. At mean 4 years follow-up, one patient had a superinfection and two others recurrence at 7 and 10 months, with surgical revision and good outcome.

Discussion: The risk vascularisation of the thigh muscles explains these localisations. Ultrasound is a sensitive exploration which suggests the diagnosis in all cases. CT and MRI confirm the diagnosis and define the cyst relations. Pathology is needed for formal diagnosis. Total pericystectomy or wide resection is the best surgical technique, although not always readily achieved.

Conclusion: Muscle hydatidosis is rare. Treatment is surgical, different from the osteoarticular localisation, similar to the visceral foci. Recurrence is exceptional. Prevention remains the best treatment.


Bertrand Coulet Jorge Boretto Cyril Lazerges Tanguy Mraovic Matthieu César Jérome Papa Michel Chammas

Purpose of the study: We compared the reinnervation capacities of two nerve transfers onto the common trunk of the musculocutaneous nerve (MC), several bundles of the ulnar nerve (UN) and three intercostal nerves (IC) in patients with high brachial plexus palsy (C5C6 or C5C6C7).

Material and methods: Prospective consecutive study of two groups: group 1: 24 transfers and two to three UN bundles in 20 patients with C5C6 and four with C5C6C7, mean age at surgery 29.5 years; group 2: 15 neurotisations of the MC by CI in four C5C6 palsies and in 11 CC5C6C7 palsies, mean age at surgery 25.7 years. Mean time from accident to operation was 5.7 months, mean follow-up 29.4 months.

Results: The first contractions of the biceps were perceived clinically at 5.2 months after the surgery in group1 versus 9.9 months for group 2. Four patients in group 1 (17.0%) did not recover active flexion greater than M3 versus four (27%) in group 2. Mean force using the BMRC score was 3.6 in group 1 versus 3.2 in group 2. When elbow flexion was ≥3 (BMRC), force could be measured at 4.5kg in group 1 and 3.0 kg in group 2. For time to management up to seventh month, the two groups were comparable concerning pertinent results, but after that delay, none of the patients in group 2 achieved elbow flexion ≥3 versus 66% in group 1 up to one year. Up to the age of 40 years, results were comparable; no pertinent result was obtained after that age in group 2 versus 66% in group 1. C5C6C7 palsies had less favourable results irrespective of the technique.

Discussion: Our results show the superiority of UN transfer over CI transfer. In patients who undergo surgery before the seventh month, the rate of pertinent outcome was comparable although the flexion force was significantly greater in group 1. After seven months, only UN transfer offers hope of a useful result, up to the twelfth month. Before the age of 25 years, results are comparable, after 40, no pertinent result was observed after CI transfer while useful contraction could be obtained up to 45 years with UN transfer. C5C6C7 forms recover less well irrespective of the technique.


Thomas Bauer Luc Lhotellier Patrick Mamoudy Alain Lortat-Jacob

Purpose of the study: The purpose of this work was to analyse the results of infection in patients with joint prostheses implanted after septic arthritis, distinguishing evolving versus cured arthritis.

Material and methods: This was a retrospective series of 70 cases of septic arthritis (in 69 patients) including 7 patients with mycobacterial infections and 63 patients with ordinary germ infections. For the seven mycro-bacterial infections (five Mycobacterium tuberculosis and two Mycobacterium xenopi), the arthroplasty was implanted on evolving arthritis and in two on arthritis considered cured. For the 63 cases of common germs (70% staphylococcal infections), the septic arthritis was considered evolving in 36 and cured in 27. For half of the cases, the arthritis was blood-borne and localised in the knee. For cases considered evolving, the arthroplasty was generally a two-phase procedure (32/36 cases). Adapted antibiotics were associated for 93 days on average (45–180). For arthritis considered cured, the arthroplasty was implanted on average 53 months (range 6–700) after the infectious episode, generally in a one-phase procedure (22/27). Adapted antibiotics were associated for 80 days on average in seven patients because of positive intraoperative samples. One patient was lost to follow-up before two years and all others were reviewed with at least two years follow-up (mean 5 years, range 2–13 years).

Results: For the seven cases of mycobacterial arthritis, one patient was lost to follow-up, six had no signs of infection at mean 7 years follow-up. For the other cases, 89% of patients who had a prosthesis for evolving arthritis were considered as cured, 6% relapsed before 18 months and 6% presented a new infection with a different germ. For arthroplasty after assumed cured arthritis, 81% of patients were considered cured, 15% relapsed before 18 months and 4% presented a new infection with another germ.

Discussion: Arthroplasty is the treatment of choice for septic evolving septic arthritis, enabling cure in more than 80%, irrespective of the causal germ, and whether cure of the infection was apparently achieved or not.


Mouhamadou Habib Sy Amadou Gueye Diouf Jean-Claude Sané Amadou Ndiassé Kassé Babacar Thiam Boubacar Mbaye Abdoulaye Bousso Seydina Issa Laye Sèye

Purpose of the study: Mycetoma designates an inflammatory pseudotumour caused by fungal or bacterial agents with a slow chronic course and characterised by the emission of species-specific grains through fistules. Like the foot, the knee is a weight-bearing zone which can lead to mycetoma of soft tissue and/or bone or articular tissue. The purpose of this work was to study the frequency of the different clinical forms and report medical and surgical outcomes of the localisation.

Material and methods: This was a retrospective analysis of consecutive files collected over a 20-year period from July 1988 to 2008 including a total of 267 cases. Twentyfive patients (22 male 3 female) had an articular or peri-articular mycetoma of the knee joint. Mean age was 31.8 years (range 18–59). The right knee was involved in 17 cases and the left in eight. Duration of symptoms was 2.2 years (range 1–25 years). Antibacterial treatment with sulfamethoxazole and exclusively for actinomycetoma was given for 10 months at least and antifungal treatment with ketoconazole as adjuvant treatment with surgery for maduromycetomas. This orthopaedic surgery was radical (three above-knee amputations) or conservative (directed healing for 5, first-intention surgery for 5 with a flap for 3 and with a graft for the others).

Results: The knee accounted for 9.23% of the localizations in our series, most common after the foot and ankle. Twenty cases were exclusively maduromycetomas with black grains; the five others were actinomycetomas: 3 red grain, 1 white grain and 1 yellow grain. The topographic forms were predominantly anterior localization: 15 cases (versus popliteal in two, the entire knee in four and unknown in four). According to the Bouffard classification, the lesions were: diffuse (n=20), polyfisutulised (n=20), sclerohypertrophic (n=1) versus two localized encapsulated forms. Local spread led to bone and joint involvement in six patients, mycosis arthritis in three complicated by a pathological fracture of the patella. At last follow-up, there have been three recurrences with limited flexion in four patients.

Discussion: Articular or extra-articular mycetoma of the knee is an infectious dermato-orthopaedic disease dominated by fungal infection. Treatment is particularly difficult in advanced stage disease, medical and surgical management can be proposed with cancerological type resection.


El-Masri Firas Shahnaz Klouche Wilfrid Graff Patrick Mamoudy

Purpose of the study: Arthrodesis is the treatment of choice for advanced-stage infection involving the tibiotarsal joint. In aseptic conditions, clinical and biomechanical experiments have shown that internal fixation can lead to a better rate of bone fusion. In septic conditions, external fixation, or a hybrid system, is preferred by many authors. The purpose of this retrospective study was to report the outcomes obtained with tibiotarsal arthrodesis with exclusive internal fixation in a septic environment.

Material and methods: From March 1992 to October 2005, twenty patients underwent tibiotarsal arthrodesis for the treatment of septic arthritis, 18 in a one-phase procedure and two in a two-phase procedure with bone graft. The series included four women and 16 men, mean age 50±15 years. The joint lesions were posttraumatic in 15 cases, related to primary osteonecrosis of the talus in one and to primary arthritis in four. Mean duration of the infection was 2.5 years. Resection of infected bone and soft tissue, to a zone considered healthy, was systematic. Arthrodesis used the Méary technique (n=9) or the Crawford-Adams technique (n=11). Fixation was achieved with screws, staples or both. Mean duration of antibiotics was 97.5±37.5.

Results: The clinical and functional outcome was assessed with the Kitaoka score. The x-rays included an ap and lateral view of the ankle and Méary views. All patients were reviewed at mean 64±36 months; none of the patients were lost to follow-up. The patients were considered cured if clinical and radiographic signs of infection were absent; deep samples confirmed relapse (same germ) or reinfection (different germ).

Discussion: The healing rate for infection was 90% (91% for Crawford-Adams). Radiographic bone fusion was achieved in 90% (100% for Crawford-Adams) with a mean delay of 4.8 months (range 3–11). The mean Kitaoka was improved 45±18.

Conclusion: Tibiotarsal arthrodesis in a septic context can be achieved by internal fixation alone. This method allows good position for the bone fusion and cure of the infection in 90% of cases.


Bertrand Coulet Jorge Boretto Cyril Lazerges Matthieu César Jérome Papa Michel Chammas

Purpose of the study: The slightest alteration of the antebrachial anatomic configuration, which constitutes a complex and precise biomechanical system, yields a limitation in pronosupination. Unlike the metaphysical region, little is known about rotational malunion involving the radial shaft. Kasten et all demonstrated in 30 cases that a rotational malunion of the radial shaft leads to significant loss in the pronosupination arc. If the proximal and distal radioulnar joints are intact, the interosseous membrane (IOM) probably plays an important role in this limitation.

Material and methods: The purpose of our study was to evaluate the impact of releasing the IOM on the pro-nosupination arc in an experimental model with a rotational malunion of the radial shaft inducing pronation.

Results: The study involved eight cadaver forearms free of all muscle structures and devoid of prior trauma. After stabilizing the elbow at 90°, the upper limb was fixed on a metal frame used as the reference to measure pronosupination. For each specimen, motion was measured initially, after osteotomy of the radius shaft to induce pronation then associated with longitudinal section of the IOM. A midshaft transverse osteotomy induced 78±7 pronation on average and was fixed with a DCP.

Discussion: The mean pronosupination arc was initially 175 in our population (81 pronation, 94 supination). After the creating the rotational malunion, this arc decreased significantly to 126 (SD. p> 0.05) (99 pronation, 27 supination). Release of the IOM increased this arc significantly from 27 to 153 (SD, p> 0.05) (105 pronation, 48supination)

Conclusion: Our study confirms the impact of rotational malunion on the pronosupination arc and shows the positive effect of releasing the IOM. Suppression of the IOM leads to a simpler biomechanics for the antebrachial system, allowing greater mobility of the bone one over the other. There are several clinical applications of this observation for the correction of shaft malunion of the antebrachial bones, but also certain corrective osteotomies for malpositions in the neurological patient.


Yves Hémon Sébastien Parratte Jean-Manuel Aubaniac François Kerbaul Jean-Noël Argenson

Purpose of the study: Besides enabling a precise calculation of the needs for blood (in ml) for each type of orthopaedic surgery, an adequate estimation of average total blood loss (TBL) as a function of total blood volume (TBV) enables initiation of blood sparing techniques. Thus, when the balance is negative, erythropoietin could be advisable. The purpose of this work was to analyse the impact of prescribing erythropoietin as a function of the expected blood balance on the rate of homologous blood transfusions. We also wanted to determine the financial impact of this prescription strategy.

Material and methods: This prospective study included 229 patients (153 THA and 76 TKA) who underwent surgery from January 2005 to December 2008 with a standard anaesthesia, analgesia and surgical protocol. TBL was considered to be 10% of TBV for THA and TKA. Mean gain in serum haemoglobin (Hb) per injection of erythropoietin (1 ampoule Eprex) was 0.8 g/dl. Using the patient’s Hb level at the preop exam (Hbpreop), the anaesthetist determined the volume available (VA) for each patient and for each type of operation. When VA was negative, the Hb needed to reach the desired level (HbA) so that VA=0 (zero risk of transfusion) was calculated. The number of Eprex ampoules prescribed (amp) was determined from the formula: (HbA-Hbpreop)/0.8. Hb levels on day 0, day 1, day 3(discharge) and day 28 were noted, as were the number of homologous transfusions and the total number of ampoules of Eprex delivered.

Results: Sixty-six patient received one amp (33.2%), 96 had two amp (42%), 40 three amp (17.5%) and 17 four amp (7.4%). For 220 patients (92%), Eprex delivered was within the approved dose (92%). The mean Hb levels were: Hbpreop=12.4, HbA=13.5, Hbd0=13.9, Hbdischarge=11.2, and Hbd28=11.9. Total consumption was 456 amp instead of 916 (229x4), i.e. a savings of 460 amp corresponding to 173 880 euros (460 x 378 euros). There were six homologous transfusions (2.6%).

Discussion: In orthopaedic surgery, adapted prescription of erythropoietin as a function of the TBL enabled, in this series, a simplification of the prescription procedure and avoided the risks related to high Hb levels > 15g with a financial savings of 760 euros per operation (173880 euros for 229 patients) without increasing the rate of homologous transfusion. This strategy is currently being evaluated for prosthesis revision surgery.


Benoît Lebel Solene Gouzy Vincent Pineau Laurent Geais Franck Dordain Claude Vielpeau

Purpose of the study: Comprehension of total knee arthroplasty (TKA) kinematics is primordial for improving the functional outcome and longevity of these prostheses. Several methods are available for evaluating knee kinematics. The purpose of this study was to determine the accuracy of the 2D fluoroscopic method in vitro, taking optoelectronic analysis as the gold standard.

Material and methods: In order to compare these two techniques, a posterior stabilised prosthesis was implanted on dry bones. The lateral ligaments were modellised with two elastic bands. Thirty flexion movements were imposed consecutively. The kinematics of this prosthetic model were recorded simultaneously using the fluoroscope and a computer-assisted surgery system. The technique used for the fluoroscopic analysis was based on the detection of the contours and projective geometry algorithms. The statistical analysis measured differences and correlations between the two systems using the root mean square (RMS) method and interclass coefficients of correlation (ICC) in addition to Bland and Altman analyses.

Results: Three hundred thirty six relative implant positions were analysed for 30 flexions from −8 to 132 degrees. The objective RMS were to the order of one degree for flexion, varus and tibia rotation. Conversely, there was a difference of 2.43±3.17 mm for the mediolateral distance (ML). Similarly the ICC were to the order of 0.9 for the six degrees of freedom of the model with the exception of ML displacement where the ICC was 0.106. These analyses were confirmed by the Bland and Altman analysis which revealed an underestimation of the ML distance by the fluoroscopic method in greatest internal rotation.

Discussion: This study is the first using a realistic model to evaluate the kinematic data provided by 2D fluoroscopy in comparison with conventional navigation data. The results show a good agreement between the two techniques and a small difference in measures excepting for the ML plane. The results are less satisfactory than those reported in the literature where data were obtained from computer simulations.

Conclusion: 2D fluoroscopy of the TKA kinematics provides precise data. Nevertheless, the limits and inaccuracies of this technique should be recognized. This study is a prerequisite for in vivo 2D fluoroscopy.


Violaine Beauthier Christian Dumontier Alain Sautet

Purpose of the study: The purpose of this paper was to report our experience with arthroscopic treatment of tendon-related epicondylalgia resistant to well-conducted medical treatment and the long-term outcomes. From September 2000 to January 2008, 25 consecutive patients underwent arthroscopic treatment performed by the same surgeon. Twenty-two patients were available for follow-up. We reviewed 26 interventions.

Material and methods: An endoarticular technique was used, with section of the lateral capsule then the extensor carpi radialis brevis and the extensor digitorum communis. Mean patient age was 45 years (36–55); five patients had work accidents (one bilateral case). Patients were assessed clinically using the Mayo Clinic Elbow Performance Score (MEPS) and for pain at rest, during daily life activities and during exercise (scale 0–10).

Results: Mean follow-up was 51 months (17.6–88.7). Pain was scored 0.38 at rest, 0.81 for daily life activities, and 4.11 for exercise. Mean function score was 90/100. Two patients underwent revision. Sixteen patients (62%) stated they were « much better », six « better » (23%) and four unchanged (15%). Twenty-one patients (81%) were satisfied, 23 would request the same procedure (88%). There was no statistically significant difference in the subgroup of work accidents versus the other patients with p=1.35 for pain at rest; p=0.51 for pain during daily life activities, p=0.37 for pain during exercise. Two minor complications (skin burn, subcutaneous infection) were observed.

Discussion: The results show improvement postoperatively. Patient satisfaction was correlated with the clinical results and the function score. Treatment of resistant epicondylalgia remains a very controversial issue; several surgical techniques have been described with good or even excellent results. Arthroscopic treatment, inspired by the work of Kuklo, was adopted by Baker, Owens and Jerosch. Our results are equivalent to those of other arthroscopy series. Longer time before resumption of occupational activities can be explain in our opinion by the greater number of patients with an occupational accident in our series.

Conclusion: Arthroscopic resection yields satisfactory results which are sustained over time, for the treatment of resistant epicondylalgia. It is an alternative to open surgery.


Enrike Van der Linden Nienke Wolterbeek Edward Valstar Rob Nelissen

Purpose of the study: Congruence between the femoral component and the insert has been proposed to decrease wear in total knee arthroplasty (TKA). This congruence should favour unidirectional movement between the components because multidirectional movements carry a risk factor for wear up to 30-fold higher than unidirectional movements. This study explored in vivo displacements between the insert and the femoral component of a prosthesis in order to determine whether they meet the required kinematic criteria.

Material and methods: Twelve patients (7 women, 5 men) aged 45 to 79 years with BMI from 23 to 35 underwent knee surgery for osteoarthritis and were included in this study. The prosthesis was a mobile plateau pros-thesis implanted by the same surgeon using a navigation system. During the procedure, four tantalum beads were implanted in the polyethylene under stereotaxic guidance. The postoperative evaluation was performed at six months with the clinical evaluation (KSS, WOMAC) a 3D fluoroscopic protocol (walking, stairs, get up and go) and a radiostereometric analysis (RSA).

Results: Active flexion under weight bearing was 118 (range 102–125) and the mean KSS 165. The videofluoroscopy combined with RSA showed congruent axial rotation between the femoral component and the insert in the flexion arc 0/60 with a mean difference of 0.38 per degree of flexion (SD 1.85). Beyond 60° flexion, the posterior displacement of the condyle was greater than the insert rotation.

Discussion: Compared with other 3D videofluoroscopic studies, this analysis adds greater accuracy due to the implantation of tantalum beads in the insert, enabling a study of insert displacement in relation to the metal components. This method demonstrates that for the implant studied here, rotation of the insert follows the displacement of the femoral component exactly from 0 to 60° flexion, this is a gliding displacement. Then beyond 60°, a gliding plus rolling movement occurs displacing the femoral component posteriorly.

Conclusion: This in vivo study in patients with a mobile plateau knee prosthesis demonstrates that the insert has a rotation exactly like the femoral component and that complete congruency is maintained between the femoral component and the insert with a pure gliding contact from 0 to 60° flexion. The prerequisite criteria for this type of prosthesis designed to reduce the wear factor are thus confirmed.


Benoît Lebel Vincent Pineau Solene Gouzy Laurent Geais Claude Vielpeau

Purpose of the study: Several authors have focused attention on the kinematics of total knee arthroplasty. In vitro studies have shown the influence of prosthetic kinematics on wear of the tibial insert. In vivo, investigations are limited for this important parameter. We propose computer algorithm which gives a linear assessment of femur penetration into the tibial insert. The purpose of this work was to test this measurement by radiostereometric analysis (RSA) on pre-worn prosthesis models.

Material and methods: A resin plateau was manufactured with four Triatlhon posterior stabilized inserts. Three of these inserts were pre-worn on the medial glenoid; wear varied from 0.8 to 1.2 mm. The wear pattern was controlled by a computer program in order to localize it on a posteromedial gliding band posteriorly to the posterior stabilization implant. A femoral component was implanted on dry bone and loaded on a simulator. RSA images were obtained for each of the plateau. Five series of images were obtained from 0 to 40° flexion. The measurement method consisted in defined a perfect middle plane based on the analysis of tantalum beads embedded in the resin plateau, the to define the point the closest to this plane belonging to the medial condyle. The norm of the normal vector for this plane passing through the lowest point of the femur was the reference. The difference of the norms of the vectors constructed from the healthy plateau and the worn plateaus was defined as penetration of the femur into the tibia insert. The rood mean square (RMS) method was used to measure intraobserver variability and the interclass coefficient of correlation (ICC) was determined.

Results and Discussion: Our results were encouraging. 0.8/to 1.12 mm wear was detected with very good accuracy. The data spread was however wide, irrespective of the wear value. The images in flexion of this model provided the most reliable readings. This study is the first offering an approach to wear measurement in vivo. The data spread should be improved by fine tuning the experimental model and the pre-wear pattern.

Conclusion: In vivo measurement of TKA wear remains a challenge in clinical medicine. Our work demonstrate the feasibility of using RSA.


Romain Gérard Florence Unno-Veith Pierre Hoffmeyer Jean Fasel Mathieu Assal

Purpose of the study: Stiffness of the ankle joint is a common complication after fracture, surgical repair, or total ankle arthroplasty. Dorsiflexion is generally the most limited movement. A few older papers have focused on this common problem in orthopaedic surgery of the ankle joint but have been controversial. The purpose of this anatomy study was to evaluate the efficacy and quantify the impact of releasing the collateral ligaments of the ankle joint on dorsiflexion stiffness.

Material and methods: The two main ankle ligaments implicated in this type of stiffness, the deep bundle of the posterior tibiotalar ligament (dPTTaL) and the posterior talofibular ligament (PTaFL), were studied. We dissected 16 talocrural joints on fresh cadavers and measured with electronic goniometry coupled with electronic dynamometry their movement in dorsiflexion after section of the dPTTaL in the first group and after section of the PTaFL in the second.

Results: The results showed a significant difference (p< 0.0003) between the two populations of ankles. Section of the dPTTaL was more effective against dorsiflexion stiffness than section of the PTaFL, even though the overall benefit in dorsiflexion was less than 10° (mean 7.45 versus 3.45). Combined section of the two ligaments did not provide a statistically significant improvement in the gain in dorsiflextion (p=0.88) compared with isolated section of the two ligaments.

Discussion: If limitation of active and passive dorsiflexion persists after classical release or lengthening of the posterior periarticular tendons of the ankle joint, or after gastrocnemius lengthening, our results show that the following surgical step could be meticulous release of the dPTTaL.


Véronique Gabrion Antoine Gabrion Jean-Marie Sérot Patrice Mertl Michel De Lestang

Purpose of the study: Dementia in the elderly subject aged over 75 years is currently an important public health problem. An important part of the activity in orthopaedic surgery involves this age group. In 2007, 16,812 elderly persons aged over 75 years were hospitalised in our University Hospital (769 in orthopaedic surgery): 1380 patients were considered demented (40 in orthopaedic surgery). The purpose of this work was to evaluate the cognitive function of this population in a teaching hospital unit of orthopaedic and traumatology surgery where the prevalence of dementia appears to be underestimated.

Material and methods: Data were collected over a period of four years. This study concerned 113 patient, including 83 women, mean age 81.8 years (range 75–92). The reason for hospitalisation was predominantly fracture of the proximal femur (73%); thirty patients had hip, knee or shoulder arthroplasty and 24 other situations. The Mini Mental State Examination (MMSE) was performed.

Results: The MMSE could be interpreted for 100 patients: < 24 for 33, 24 to 26 for 29 and > 27 for 38. Among the 24 patients with no cognitive disorder known before hospitalization (nine patients known to be demented were removed from the analysis) and for whom the MMSE was completed entirely, the most frequent alterations were noted for attention, calculation, and recall-memory items.

Discussion: Finally, one-third of the subjects aged over 75 years and hospitalized in our unit presented signs of altered cognitive function according to the MMSE(< 24). This score is one of the criteria for frailness of the elderly subject. This population has an unstable precarious medicosocial status with defective adaptation to stress and change in environment. These persons are exposed to a high risk of morbidity, mortality, dependence, longer hospital stay and institutionalization. The purpose of this screening is to improve management for these patients by proposing more specifically adapted care.

Conclusion: It is thus indispensable to screen for cognitive disorders systematically in patients aged over 75 years hospitalized in a surgery unit. The MMSE score can be used for this purpose. This work is in favour of a physician or better a geriatrician within the unit who could be financed directly by his-her own sector of activity.


Nicolas Krantz François Giraud Bruno Miletic Julien Girard Charles Berton Antoine Duquennoy Henri Migaud Gilles Pasquier

Purpose of the study: The objectives of this work were to assess the stability of outcome achieved after Duquennoy procedure to tighten the lateral capsule-ligament structures of the ankle joint. To do this, we reviewed the same series of patients at 3 and 25 years follow-up to analyse the very long-term stability, laxity, and stiffness of the ankle joint and any osteoarthritic degradation.

Material and methods: From 1975 to 1986, we performed 75 Duquennoy procedures on the lateral capsule and ligament structures of the ankle joint. At mean 25 years follow-up (2007) we were able to review 28 ankles (27 patients) with the same method as applied in 1980 (3 years follow-up). The function outcome was assessed with the Good, Karlsson, Duquennoy and Tegner scores. Clinically, other than joint range of motion, were noted varus laxity or anterior drawer. Static x-rays were obtained to search for signs of osteoarthritis and stress images to measure talocrural laxity, in comparison with the preoperative figures and the 1980 data.

Results: There were two early technique failures (one persistent talocrural instability, one subtalar instability). Good and Karlsson scores were good or excellent in 92% of cases. Patients were very satisfied with the operation and the VAS was 8.9/10. Pain and occasional instability were reported by 27% of patients. There was no talocrural no subtalar stiffness at last follow-up. Radiographic laxity declined significantly between the preoperative value and the last review. Only one patient presented a narrow talocrural space (less than 50% narrowing). Eight patients had osteophytes whose presence was not correlated with poor functional outcome. These osteophytes were also present on the controlateral side. Importantly, there was no significant difference in the mean function scores between 3 and 25 years follow-up (Duquennoy score). Similarly joint range of motion and radiographic laxity remained stable over time.

Discussion: The Duquennoy procedure to tighten the lateral capsule and ligament structures is a simple technique with rare complications which provides excellent results both in terms of ligament stability and in terms of preservation from degenerative osteoarthritis. These results remain stable over time. Conversely, the technique has no action on the subtalar joint and should not be proposed as treatment for associated subtalar laxity, if diagnosed.


Arnaud Largey Wayan Hebrard Mazen Hamoui Olivier Roche Patrick Faure François Canovas

Purpose of the study: Osteotomy of the first metatarsal has become the gold standard treatment for hallux valgus. We report a study on the changes in radiographic findings as a function of the degree of translation of the distal fragment of the metatarsal during scarf distal wedge osteotomy.

Material and methods: From the cohort of patients who underwent hallux valgus surgery in our unit, we collected 118 anteroposterior x-rays of the forefoot. Computer-assisted image processing established a trigonometric analysis of each forefoot before and after standardised virtual surgery. Variations in standard morphological measurements (phalangeal valgus: M1P1; metatarsal varus: M1M2; orientation of the joint surfaces of the first metatarsal: proximally (PMAA) and distally (DMAA).

Results: The successive translations significantly modified all of the morphological measurements. For M1M2, intermediary translation corrected the metatarsal varus (< 5) in 72% of the cases, maximal translation in 97%. For the M1P1 angle, intermediary translation only corrected the phalangeal valgus (< 8) in 44% of cases, maximal translation in 31%. For the DMAA angle, intermediary translation corrected the distal articular orientation (< 6) in 66%, maximal translation in 97%. Distal translation of the first metatarsal aggravated the obliquity of the proximal joint surface from a mean 1.57±4.5 to 7.7±4.7, with intermediary translation and to 13.92±4.9 with maximal translation.

Discussion: Considering the large number of techniques proposed, the choice of one osetotomy model is reductive, but it does demonstrate via a geometric application the limits of osteotomy translation of the first metatarsal for the correction of hallux valgus.


François Lavigne Fabrice Gaudot Philippe Piriou Thierry Judet

Purpose of the study: The purpose of this prospective controlled trial was to evaluate the influence of the tibial stem design on the primary fixation of the tibial base of a total ankle arthroplasty (TAA) and on radiographic remodelling of adjacent bone.

Material and methods: Sixty Salto™ TAA with a short stem were studied with one to three years follow-up. This series was mated with a control series of 60 TAA using conventional ‘cannon’ implants. All patients were assessed clinically with the AOFAS score and radiographically on the loaded ankle.

Results: The two consecutive series were reviewed a mean 23 months. The mean AOFAS score at review was 83.6 points (mean gain 45 points). The functional analysis did not disclose any difference between the two series. There was no evidence of tibial piece migration. The incidence of lucent lines, all partial (32.5%) and bone remodelling was higher in the cannon TAA series than in our short-stem TAA series, but the difference did not reach statistical significance. Considering all prostheses together, the incidence of bone condensation was 39.3%; and bone defects 16%. Young age appeared to be the only factor correlated with the development of defects (p=0.01). One progressive defect was grafted. Two prostheses were removed (one talar necrosis and one malposition).

Discussion: Primary fixation of the tibial base of the Salto™ prosthesis is excellent, irrespective of the design of the anchor stem. Suppression of the cannon did not reduce statistically the phenomena of osteolysis. The mechanism of the periprosthetic osteolysis is probably plurifactorial, associating biochemical and mechanical factors.


Michel Bonnin Jean-Raphaël Laurent Fabrice Gaudot Jean-Alain Colombier Thierry Judet

Purpose of the study: The results of the first total ankle arthroplasties (TAA) using the Salto™ prosthesis were published in 2004 with mean 35 months follow-up. The purpose of this work was to update the results of the initial multicentric series.

Material and methods: From 1997 to 2000, 98 TAA were performed with a Salto™ prosthesis in three centres: 62 women, 36 men, mean age 56 years, age range 26–81 years, mean BMI 24.3 kg/m2. The patients had osteoarthritis (n=65; posttraumatic 43, post-instability 8, primary 14), rheumatoid arthritis (n=29), and sequel of septic arthritis (n=4). At last follow-up, nine patients had died (none had had revision surgery of the ankle) and one patient had been amputated for an unrelated reason. The remaining patients (88 TAA) were reviewed in an outpatient clinic with a mean 102 months follow-up (range 65–134). None of the patients were lost to follow-up.

Results: Seven prostheses were replaced by an arthrodesis (six osteoarthritis and one rheumatoid arthritis): three for defects at 44, 72 and 101 months after implantation, two for unexplained pain after 32 and 57 months, one for tibial loosening after 62 months and one for infection after six months. One tibial piece was changed for loosening and fracture of the polyethylene insert after 100 months (revision with a longer anchor piece). Two 3 mm polyethylene inserts were changed alone for fracture after 72 and 122 months. Five TAA were reoperated for stiffness: removal of bone fragments±synovectomy. Four TAA were grafted for secondary defects (two tibia and two talus). One lateral maleolar piece was removed for loosening after 88 months. There were two infections treated by synovectomy, wash-out and antibiotic therapy. The survival rates were 92% for failure=removal of the prosthesis; 91% for removal or replacement of one component; 89% for removal or replacement of one piece, including the polyethylene insert. The survival rate (prosthesis removal) was better for rheumatoid disease (97%). The AOFAS score at last follow-up was 81.5±12 (80.5±10.3 for osteoarthritis and 76.4±14.8 for rheumatoid disease).

Conclusion: These results underscore: the importance of rigorous technique and careful patient selection (five revisions for defective technique); the higher risk of infection (three cases); the importance of the thickness of the poly-ethylene insert (three fractures on 3mm inserts). Seven patients underwent revision to graft defects, four successfully and three failures (secondary arthrodesis).


Frédéric Jacquot Mokrane Ait Mokhtar Alain Sautet Jean-Marc Féron

Purpose of the study: Treatment of calcaneal fractures is specific because of the fact that these fractures dis-organise the subtalar joint, requiring precise reduction. The clinical result is not always satisfactory considering the efforts made to obtain reduction and fixation. Functional treatment often gives acceptable clinical results, but leaves important anatomic and functional sequelae. We developed a technique for percutaneous balloon reduction and cementoplasty similar to the method used for vertebral fractures treated with the same material.

Material and methods: We describe four cases of thalamic fractures treated surgically in a semi-emergency setting. The patients were four women, mean age 39 years (range 26–55). Fractures included vertical compression fractures of the thalamic surface in all cases. The operation was performed under radiographic control in the operative theatre and included a phase for percutaneous reduction and a phase for cemented fixation, allowing a minimal incision and control in two planes.

Results: Operative time was 30 minutes and blood loss was negligible. Bone healing with maintenance of the subtalar reduction was achieved in all cases. The clinical result was remarkable, with sedation of the pain and oedema within hours and weight bearing within a few weeks. One patient developed a lateral submaleolar impingement which required infiltration at four months. All patients were totally pain free and had no radiographic evidence of osteoarthritis at two years.

Discussion: Percutaneous reduction cemented fixation is a new method for the treatment of thalamic fractures of the calcaneum. We demonstrated the feasibility in a small series; the procedure was simple and allowed effective treatment compared with the classical methods.

Conclusion: These excellent clinical results are encouraging for the development of the technique and incite us to propose this method as the first-line treatment for displaced thalamic fractures. We are working on the development of this concept.


Chahine Assi Camille Samaha Moussa Chamoun Diana Bitar François Bonnel

Purpose of the study: The purpose of this retrospective study was to evaluate the reliability of the sural flap with a distal pedicle for covering tissue loss of the posterior aspect of the heal and the malleolar region in diabetic patients.

Material and methods: We present a retrospective consecutive series with 28 month follow-up. Thirteen flaps in 13 patients (10 men, 3 women), mean age 64 years. A homolateral flap was used in all cases, covering on average 48 cm2. Substance loss involved the hind foot in ten cases and the malleolar region in three. Three patients had recent bone trauma, four had chronic osteitis and six a pressure wound involving the heel. All patients had non-insulin dependent diabetes mellitus.

Results: The flap head in 24 days on average (range 18–45), the donor site in 15 days. Eleven patients were able to wear normal shoes. At last follow-up all patients were free of infectious recurrence. There was one flap necrosis, three necrotic borders (one skin graft), two cases of venous insufficiency, and ten cases of hypoesthesia of the lateral border of the foot.

Discussion: There have not been any reports in the literature of the neurocutaneous sural flap with a distal pedicle for diabetic patients. In our series, this flap was found to be a reproducible solution for covering substance loss of the heel and malleolar region in the diabetic.

Conclusion: This flap with a long pedicle does not require microvascular qualification. It is easy to perform, induces few functional sequelae. For diabetic patients, it is an alternative to amputation, without compromising future options since the vascular and muscle stock are preserved.


Olivier Laffenêtre Hicham Larrach Véronique Darcel Loïc Villet Dominique Chauveaux Grecmip

Purpose of the study: Minimally invasive techniques are gaining popularity. We report our experience with the treatment of hallux valgus using a hybrid technique combining wedge osteotomy of M1 and other procedures (arthrolysis, phalangeal osteotomy) performed percutaneously.

Material and methods: This was a prospective consecutive series of 172 operated feet in 139 patients, mean age 2005 to 2007. All procedures were performed by the same operator and reviwed by an independent observer at mean maximum follow-up of 18 months. The same operative technique was used; the only variable was Akin osteotomy performed (in 67%) or not, fixed (one out of three) or not. Assessment compared pre and postoperative values for the angles M1M2, M1P1, DMAA and DM2AA, joint range of motion, Kitaoka score and morbidity.

Results: At maximum follow-up, the independent observer noted: 40.6% and 71% improvement in M1M2 and M1P1 angles, 42.3% in DMAA and 122% in DM2AA, 32.3% in the P1P2 angle, and 71.8% in the Kitaoka score. Dorsiflexion was diminished 4.2%, plantar flexion 19.6%. Material was removed in 7%, and complication rate was 2.9%; there were no deep infections. The procedure was achieved in an outpatient setting from 57% of patients. Excepting one patient who was disappointed, all other patients were satisfied or very satisfied with their operation.

Discussion: Wedge osteotomy is an attractive first-intention procedure for the treatment of moderate hallux valgus. It is even more so when combined with the academic percutaneous surgery imported in France by GRECMIP indicated in a still limited number of situations. All parameters are significantly improved with a perfectly controlled morbidity. The absence of deep infection despite (or thanks to) refection 15 days after the first dressing is particularly noteworthy. This method has the approval of nearly 100% of patients and presents many advantages: absence of pain related to unwonted mobilization during wound care, maximal protection of the operated foot in the dressing which is humid at first then hardens forming a shock absorber without extra cost for the postoperative care.

Conclusion: We validate this concept which constitutes a fundamental progress in forefoot surgery, particularly in phase with the current concern for cost containment.


Didier Mainard Ioana Mothé Jérome Diligent Elie Choufani Armelle Breton Laurent Galois

Purpose of the study: Basimetatarsal osteotomy to correct hallux valgus deformity by subtraction of a lateral wedge does not take into account the distal angle of the first metatarsal (DMMA). The purpose of this study was to demonstrate that the preoperative DMMA has an effect on the correction of the metatarsophalangeal angle and the duration of the result.

Material and methods: This retrospective study included 76 patients, mean age 58 years (84 feet). The M1P1 angle of the first ray was 34 on average, the DMMA 10 (two-thirds of the patients had a DMAA > 10. The same operator used the same technique for all procedures: lateral wedge osteotomy of the base of the first metatarsal with metatarsophalangeal release. Basal osteotomy of the first phalanx was performed for severe deformity. Radiographic measures were made on the dorsoplantar anteroposterior images in the weight-bearing condition preoperatively, at four weeks and at last follow-up. All images were read by an independent observer. Mean follow-up was 11 months. The DMMA measurement was the angle between the distal joint surface of the first metatarsal and the alignment of its diaphysis.

Results: Mean postoperative correction of the hallux valgus was 25 with a mean M1P1 of 9. This result remained stable without loss of correction at last follow-up. The mean postoperative DMAA was 10 and remained unchanged.

Discussion: Determination of the DMAA can be difficult because of preoperative pronation of the forefoot, compromising the reliability of the measurement. The literature also reports intraobserver and interobserver variability of this angle. Mean follow-up was not greater than one year, but the loss of correction generally occurred during the first six postoperative months. The operative technique enabled sufficient and stable correction over time. A pathological value for DMAA, even if large and uncorrected, does not prevent a good correction of the M1P1 angle and to maintain that correction. The clinical result is also the same irrespective of the preoperative DMMA.

Conclusion: Wedge osteotomy of the base of the first metatarsal is a reliable procedure for the treatment of hallux valgus. The value of the DMAA has no effect, in our experience, on the quality of the correction, or on the duration of the result.


Olivier May Dragos Schiopou Marc Soenen Julien Girard Donatien Bocquet Gilles Pasquier Giraud Anne Cotten Henri Migaud

Purpose of the study: Drilling along yields disappointing results for osteonecrosis of the femoral head due to the high failure rate despite prolonged rest and also because of the risk of fracture. To prevent these problems, we have developed a new drilling technique which was evaluated prospectively.

Material and methods: The procedure performed percutaneously uses a lateral cortical orifice measuring 5mm, non-concentrated autologous bone marrow was injected after drilling. Osteoinductive protein (BMP7) was associated in random fashion (groups BMP+ and BMP−). Ficat stage 1 and 2 necrosis was included. Outcome was the rate or revision for prosthesis.

Results: Forty hips (36 patients) were included and assessed at mean four years (range 2–6). The necrosis was related to: alcoholism (n=5), cortisone (n=25), barotraumas (n=2), metabolic disease (n=4), idiopathic condition (n=4). Group BMP- (drilling+bone marrow) included 24 hips and group BMP+ (drilling+bone marrow+BMP7) 16 hips. The groups were comparable regarding necrosis stage (15% stage 3, 65% stage 2, 20% stage 1) and mean Koo index (27 BMP+ vs 34 BMP-; NS). There were no infections and no fractures despite immediate and complete weight-bearing. The revision rate for prosthesis was higher in the BMP- group (67%) than in the BMP+ group (43%) but the difference did not reach significance (p=0.10). The failure rate was not affected by the severity of the necrosis in the BMP+ group: all stage 3 hips were revised in the BMP- group versus none in the BMP+ group. The only variable predictive of revision for prosthesis was the Koo index (p=0.02).

Discussion: Adjunction of BMP did not improve significantly the success rate of drilling with bone marrow adjunction but adding BMP appeared to limit the unfavourable impact of server necrosis observed in the BMP- group. To reach a statistical power of 80%, 40 cases would be needed in each arm. This threshold has not yet been reached. It can be noted however that the proposed method does ensures early weight bearing without the risk of complications. Similarly, since it is a percutaneous procedure, later arthroplasty is not compromised. The principle confounding factor, the richness of the bone marrow, was not assessed, motivating a new randomized trial with measurement of CFU-F.


Thomas Bauer Alain Lortat-Jacob Philippe Hardy

Purpose of the study: Different metatarsal osteotomies performed via a percutaneous approach can be used to correct hallux valgus. The purpose of this work was to analyse the clinical and radiographic results of percutaneous treatment of hallux valgus using a distal wedge osteotomy of the metatarsal.

Material and methods: This was a consecutive prospective series of 125 cases of hallux valgus treated by the same surgical technique, distal wedge osteotomy of the metatarsal without fixation. Percutaneous lateral arthrolysis and percutaneous varus correction of the first phalanx were associated. The AOFAS function score for the forefoot was determined preoperatively and at last follow-up. Time to normal shoe wearing and to resumption of occupational activities were also noted. Angle correction was determined on the anteroposterior weight-bearing image. All patients were reviewed at mean 20 months (range 12–40).

Results: The AOFAS forefoot function score was 46/100 preoperatively and 87/100 at last follow-up. Mean motion of the metatarsophalangeal joint was 95 preoperatively and 80 postoperatively. Mean metatarsophalangeal valgus was 30 preoperatively and 12 at last follow-up. The mean intermetatarsal angle improved from 13 to 8 and the orientation of the joint surface of the first metatarsal (DMAA) improved from 11 to 7. The metatarsophalangeal joint of the first ray was congruent in 45% of the feet preoperatively and in 88% postoperatively. Mean time to wearing normal shoes was seven weeks for the treatment of hallux valgus alone and three months for surgery of the first ray and lateral rays.

Discussion: Percutaneous treatment of mild to moderate hallux valgus by distal wedge osteotomy of the metatarsal enables good clinical and radiographic improvement. The surgical technique requires experience with percutaneous surgery of the forefoot to avoid the main complications: secondary displacement in elevates and excessive shortening of the first metatarsal. This technique restores metatarsophalangeal congruence of the first ray compared with Isham-Reverdin osteotomy.


Jean-Christophe Chatelet Bruno Balay Louis Setiey

Purpose of the study: Cementless stems completely coated with hydroxyapatite have confirmed long-term stability with 25 years follow-up for the oldest models (Furlong, Corail). Different bearings do not all have the same stability because of polyethylene wear debris. Unipolar replacements with a stable femoral implant raise the issue of changing the head on a used morse cone. Can a new alumina head be positioned on an old morse cone or must a metal head be used to avoid the risk of alumina fracture?

Material and methods: From 1993 to 2005, among the 228 revision hip prostheses in our centre, we reviewed retrospectively 79 unipolar replacements with implantation of a new ceramic head on a stable femoral implant (Corail). The other replacements were bipolar for 113 and unipolar with a metal head in 36. The reasons for the replacement were cup loosening (n=68), major polyethylene wear (n=11). Mean age was 71 years, 42 men for 37 women, mean time to reoperation 11 years (range 7–15). The stability of the femoral stem was examined on the intraoperative x-ray. The head was extracted with a mechanical extractor and the morse cone was protected throughout the operation. The quality of the titanium cone (12/14) was assessed visually as recommended by P. Hernigou (RCO 2003). Acceptable deterioration: intact cone or aspect of corrosion. Unacceptable deterioration: inclined cone, impacted cone, cone with wide truncation. A new alumina head was implanted on the cleaned, dry cone. The cup was replaced with a screwed socket (Tropic, Spirofit) and 64 polyethylene inserts for 15 alumina inserts.

Results: Sixty-one patients were reviewed. Seventeen patients died with no incident concerning the prosthesis; one patient was lost to follow-up. Mean follow-up since revision was nine years (range 2–15). Three cups were changed: two for recurrent dislocation and one for early migration, with a new head replacement. There were no head fractures and no cases of head decoaptation.

Conclusion: Although we have not had any incidents in this series, reimplantation of a new alumina head on an old morse code is not recommended by the manufacturers; but it is not prohibited if the cone is not macroscopically worn and remains clean and dry at reimplantation of the head. We now use alumina heads with an integrated 12/14 titanium sleeve. These sleeves need to be validated in the long term, but at the present time allow us to use large heads and an alumina-alumina bearing.


Olivier Roche Frank Wein Charles Dezaly Nicolas Paris François Sirveaux Daniel Molé

Purpose of the study: The PFM-R (Zimmer) prosthesis is a straight modular stem made of sanded titanium designed to favour spontaneous bone reconstruction. The purpose of this work was to analyse the clinical and radiographic results of this implant.

Material and methods: This was a consecutive prospective series of 154 patients who underwent surgery from 1998 to 2007 (15 first-intention prostheses and 139 revisions for severe loosening [Paprosky stages 3 and 4]). Revision included a clinical evaluation (PMA score) and radiographic assessment (migration, bone regeneration, stress shielding, osteointegration, Le Béguec score) as well as a survival analysis.

Results: At mean 4.6 years follow-up (1–10 years), three patients had died, two were lost to follow-up and 18 implants were removed, 11 for infection, six for migration and one for defective technique. The PMA score improved from 8 (0–16) to 15.8 (5–18). Mean pivot impaction was 4 mm (0–50), statistically dependent on initial bone stock, form of the isthma, the corticomedullary index in the implantation zone, length of anchor, and time to weight bearing, but not femorotomy nor zone of primary stability. Bone stock was good in 73% at poor in 27% (15 stress shielding, nine infectious osteolysis, 16 absence of bone regeneration). Stress shielding was related to length and diameter of the implanted pivot (p< 0.05). Bone regrowth was statistically dependent on the number of prior operations, type of stem explanted (cemented), initial bone stock, form of the isthma and quality of the surgical reconstruction. The implant was osteointegrated in 128 cases (86%). The analysis of the prosthetic anchoring showed that primary stability was mainly diaphyseal (90%) then secondarily global (83%). Osteointegration depended statistically on the number of prior operations, initial bone stock, form of the isthma and bone regrowth, but not femorotomy. The overall Le Béquec score reached 14.7 (2–20) at last follow-up.

Discussion: The PFM-R enabled bone regeneration and osteointegration in the majority of patients. The quality of the femoral reconstruction around the implant appears to be fundamental. Massive stems should be avoided as they lead to stress shielding. The limits for use of this implant are osteopenia and absence of an isthma.


Bruno Miletic Nicolas Krantz Julien Girard Gilles Pasquier Olivier May Marc Soenen Denis Van de velde Henri Migaud

Purpose of the study: Locked implants have yielded favourable results for femoral bone reconstruction for revision total hip arthroplasty, but defective integration has also been reported due to insufficient bioactive coating. The purpose of this work was to evaluate a locked pivot with a two-third proximal hydroxyapatite coating.

Material and methods: From 1996 to 2007, 158 femoral implants (Linea™) were implanted for hip arthroplasty revision. The 143 cases with more than one year follow-up were reviewed (14 deaths, 1 lost to follow-up); 83 revisions for aseptic loosening, 41 periprosthetic fractures, 19 revisions in an infected context. Patients were reviewed retrospectively by a non-operator observer. These were older patients (mean age 68 years, range 31–93) and 36 patients had complex situations requiring at least two prior prostheses; 25% had severe grade 3 or 4 (SOFCOT) bone lesions and 59% diaphyseal damage.

Results: Clinical improvement was significant, the Postel Merle d’Aubigné score improved from 7.7 + 4.3 (0–17) to 15.6 + 2.2 (8–18) at mean 50 months (14–131) (p< 0.001). At last follow-up, 14 patients (10%) reported thigh pain and only seven pivots (5%) had not achieved Engh osteointegration (five with thigh pain two without). There were no fractures. There was on non-union of the femorotomy. According to the Hoffman index, femoral bone regeneration was significant at the metaphyseal and diaphyseal levels. Eighteen of the 19 infections cured, all periprosthetic fractures healed. The implant survival was 88.9% at 91 months (65–96.7%). There were five pivot replacements for non integration and/or thigh pain which resolved in all cases; there were no other pivot replacements. The quality of the metaphyseal and diaphyseal filling was predictive of the quality of the bone fixation of the pivot (p< 0.01).

Discussion: Compared with older models of locked pivots, this implant reduced the rate of thigh pain while allowing constantly satisfactory bone reconstruction. The metaphyseal and diaphyseal filling index is the main factor predictive of clinical and radiological success by favouring osteointegration. Maximal filling, obtained with a full range of implant diameters and lengths, contributes to this good result.


Philippe Hernigou Michel Saaman Julien Amzallag Georges Laval Patrick Dohn Razi Ouanes Redouane Jalil Alexandre Poignard

Purpose of the study: When the acetabular component is revised alone, if the femoral stem has not been loosened, the question becomes what should be done about the osteolysis of the femur: Change the femoral piece systematically and graft the osteolysis? Curettage and grafting of the osteolysis? Curettage alone? This study reports the outcome of superior femoral osteolysis with a calcar granuloma and no other procedure (no curettage) after replacing the cup.

Material and methods: This was a retrospective analysis of 54 acetabular revisions performed from 1988 to 1998. The cemented femoral piece was stable, with no lucent line and in position since the initial implantation. The reoperation consisted in cementing a new polyethylene cup (< 32 mm) with or without a graft. The femoral head was initially ceramic (alumina 29 and zircon 25) and was preserved in ten cases (alumina) and changed systematically for the zircon heads. New heads were implanted: 20 alumina (32mm) and 24 metal. Calcar osteolysis was measured in mm2 on the x-rays before and after changing the acetabular piece and then regularly every year to last follow-up (10 to 20 years).

Results: Preoperatively, superior femoral osteolysis was 156 mm2 (48–576m2) situated in Guren zone 1 and 7. At last follow-up, it was 135 mm2 (38–616 mm2) with no femoral loosening, decreased in 34 cases, unchanged in 11 and increased in 9. Spontaneous decline in preoperative osteolysis was observed when the bearing was alumina-polyethylne and the preoperative osteolysis was less than 100 mm2. Increased osteolysis (minor but undeniable) was observed with the couple was metal-polyethylene and when the preoperative osteolysis was > 300 mm2.

Discussion: If the superior femoral osteolysis does not compromise the stability of the femoral implant when undertaking isolated revision of the acetabular component alone, it can be neglected. Changing the bearing stabilizes the progression of the osteolysis and does not appear to compromise the mid-term outcome (15 years) for the femoral piece. Spontaneous decline of the osteolysis can be observed if the initial osteolysis is less than 1 cm2 and if the new bearing is alumina-polyethylene.


Dominique Poitout Richard Volpi Pascal Maman Alban Merger

Purpose of the study: Reconstruction of the acetabulum is becoming increasingly necessary due to the longer life expectancy of patients with a total hip arthroplasty (THA); it can also be needed after trauma or resection of a bone tumour.

Material and methods: For 39 cases, we used a bone bank acetabulum with variable size for simple reconstruction of a part of the acetabulum (n=6) or to replace the entire acetabulum (n=19) or even an entire hemi-pelvis (n=14) in patients with more or less extensive bone loss. For 18 cases, resection was necessary to remove a bone tumour (16 chondrosarcomas and two giant-cell tumours), in 19 cases the reconstruction was necessary after multiple operations, and in four others due to traumatic destruction.

Results: Allograft integration was successful in nearly all patients (two cases of necrosis required a secondary prosthesis, 12.5%) and in two cases we noted immunological reactions with a serous effusion. There were no local infections. For osteocartilaginous acetabuli (n=7) the integration was quite satisfactory, certain patients have been followed for more than 26 years with no evidence of osteoarthritis.

Discussion: Use of a well-established protocol for hypothermia and the absence of secondary sterilisation yields grafts with preserved mechanical properties. The use of cyropreserved osteocartilaginous allografts offers hip for good integration free from degenerative osteoarthritis.


Jean-Charles Rollier Remi Philippot Jean-Pierre Vidalain

Purpose of the study: The pertinence of locking for major femoral revision remains a controversial issue. We conducted a retrospective multicentric study to assess the benefit and potential clinical and radiographic complications after using a long locked stem entirely coated with hydroxyapatite.

Material and methods: Our series included 77 patients (42 women, 35 men), mean age 71 years (range 34–90) reviewed at minimum one year. A modular implant was used; the long curved stem allowed total integration. Screws guaranteed distal locking. There were 71 revision THA on trochanteric-shaft fractures, three shaft nonunions, 34 aseptic loosenings, 9 septic loosening, 21 fractures on prosthesis, 6 implant failures and one instability. Seventy percent of patients had stage 3 and 4 bone lesions. Mean follow-up was 60 months.

Results: At last follow-up, 90% of patients were satisfied or very satisfied. The mean Harris function score improved from 32 to 83 and the PMA from 7 to 15. Sixty-four patients were pain free and 22% had pain solely under stress. There were 15 bone complications: dislocation (n=3), early infection (n=3 including 2 recurrences), implant failure (n=2), secondary femur fracture (n=5). Stem survival was 94% at nine years. Radiographically, total stem stability was noted in 73 patients (95%); instability was noted in four cases of fracture. Undeniable metaphyseal improvement was noted in 20% of cases, more modest improvement in 32%; the situation was considered unchanged in 31%. Locking was successful in all cases; cortical bone in contact with the locking screw was unchanged in 59 cases, slightly thickened in 16, including one case with a context of septic recurrence. The locking was dismantled in two cases (one empirically and one for pain), but the stem remained stable.

Discussion: Major damage to the femur can compromise stabilisation of the proximal or diaphyseal implants. Distal locking contributes to the initial mechanical stability, indispensable for secondary osteointegration of the implant. However, with total hydroxyapatite coating, rapid fixation in healthy zones is also crucial. Reconstruction of metaphyseal bone is not easy to quantify, but the absence of bone absorption is noteworthy.


Charles Dao Jean-Michel Laffosse Hocine Bensafi Jean-Louis Tricoire Philippe Chiron Jean Puget

Purpose of the study: We report the clinical and radiographic results of a series of revision total hip arthroplasties performed for aseptic loosening using a non-demented modular femoral implant (PP).

Material and methods: From 1991 to 2003, 146 revisions of total hip arthroplasty were performed using the same non-cemented modular femoral implant (PP). At mean nine years follow-up (3.5–17 years), 24 patients had died, 26 had insufficient data for review and 39 were lost to follow-up. The analysis thus included 54 cases. All revisions were performed for aseptic loosening. Mean age at surgery was 60 years. Preoperative bone damage, according to the Sofcot classification, was grade I and II (69%), grade III (26%), grade IV (5.5%). Clinical outcome was assessed with the Harris and Postel-Merle-d’Aubigné scores. The radiological review analysed stem anchoring, lucency and periprosthetic reconstruction.

Results: At mean nine years follow-up, the mean Harris score was 71 points, the mean PMA score 12.8 points. Patient satisfaction was 70%. There were five cases with deep infection (9%), five with dislocation and six intra-operative periprosthetic fractures. Trochanterotomy non-union was noted in 26% of patients. Mean impaction of the femoral stem was 5 mm (range 0–16 mm). There was a statistically significant association between the degree of bone damage and the quality of the bone reconstruction (p=0.012). Mean increase in cortical thickness in zones 1 and 2 (Gruen) was 1.1 mm and 1.6 mm respectively. In Gruen zones 2 and 6, the gain was 6 and 10 mm respectively. There were nine surgical revisions (17%) for deep infection (n=4), recurrent aseptic loosening and fracture of the femoral implant (n=1). The ten-year survival taking aseptic loosening as the endpoint was 90%.0

Discussion and Conclusion: Our work showed the good long-term results obtained with this implant for revision total hip arthroplasty. It allows clinical improvement, periprosthetic bone reconstruction and a low rate of surgical revision.


Nicolas Bronsard Nicolas Morin Salvo Cédric Pelegri Istvan Hovorka Fernand de Peretti

Purpose of the study: The treatment of thoracolumbar fractures has evolved over the last five years with cementoplasty percutaneous osteosynthesis in addition to the gold standard orthopaedic or surgical treatments. This percutaneous method preserves muscles and maintains reduction to healing. The purpose of this work was to evaluate our results in traumatology patients after five years experience, deducting our current indications.

Material and methods: From February 2004 to February 2009, we included 60 patients with a type A or B2 thoracolumbar fracture free of neurological problems and who had more than 10° kyphosis. Reduction was achieved in hyperlordosis before the percutaneous procedure. In other cases we used open arthrodesis. This was a retrospective analysis of a consecutive monocentre series including 37 men and 23 women, mean age 37 years. The injury was L1 and T12 in the majority. Classification was A1 and A3 for the majority. Osteosynthesis was achieved with an aiming compass and radioscopy. A removable corset was used as needed. Reduction and position of the screws as well as need for a complementary anterior fixation were assessed on the postoperative scan. Clinically, follow-up measured pain and quality of life (VAS and Oswestry), radiographically, vertebral kyphosis.

Results: Mean follow-up was 24 months. At last follow-up, the VAS was 15/100 and the Oswestry 16/100. Material was removed in ten patients. Early in our experience one patient developed neurological problems postoperatively requiring revision surgery. Postoperative vertebral kyphosis was stable at three months and was sustained at two years. Body healing was successful in all cases. There were no cases of material failure.

Discussion: This is a reliable reproducible technique in the hands of a spinal surgeon. Material removal can be proposed about one year after implantation. After the age of 65 years, we favour cementoplasty. For others, we propose a sextant for A1, A2, A3 or B2 fractures with more than 15° vertebral kyphosis. This percutaneous material had major advantages for tumour surgery, for multiple injury patients and for traumatology (especially when a double approach is used).

Conclusion: Percutaneous osteosynthesis of vertebral fractures is now the gold standard for well defined indications. Two therapeutic fundamentals are reduction on the operative table and preservation of the muscle stock. These satisfactory results should be confirmed after removal of the implants.


Boumediene Sadok Hervé Vouuaillat Jérome Tonetti Ahmad Eid Arnaud Bodin Philippe Merloz

Purpose of the study: We present the clinical and radiologic results of a prospective series of 20 patients who had percutaneous osteosynthesis of the thoracolumbar spine using a longitudinal system with monoaxial screws.

Material and methods: Twenty patients, 12 women, were treated from February 2008 to February 2009. Mean age was 44 years (15–61 years). Fractures were from T4 to L5, five patients had two levels fractured. There were 18 Magerl A and two type B. None of the patients had neurological problems. The reduction was achieved with a postural method and instrumentation with monoaxial screws using the percutaneous longitudinal method. Two levels were instrumented for 12 patients, three levels for three and five levels for four. Vertebroplasty was associated in nine patients. Pain (VAS), vertebral kyphosis (VK), regional angle (RA) were assessed pre-, postoperatively and at last follow-up. Operative time, blood loss, and duration of hospital stay were noted. Pedicle implantations were controlled on the scanner.

Results: Mean follow-up was ten months (3–19 months). In the preoperative phase, the VAS was 7/10, VK 17 (8–26), RA 16.6 (4–30). Postoperatively VAS was 4/10), VK 8 (4–15), RA 10.4 (−3 to 27). AT last follow-up VK was 8.5 and RA 12. Mean operative time was 90 minutes (40–180). On the postoperative scan, 23 of the 106 screws implanted had an extraosseous position (21%) including seven cranial screws. None of the patients developed a neurological deficit postoperatively. The first rise from bed was on day 1 in 14 patients. Mean duration of hospital stay was eight days (6–35).

Discussion: This reduction method provides a gain in VK (−9), a value between orthopaedic treatment (−8 gain) and surgical treatment as reported at the Sofcot in 1995 (−11.1 gain). The reduction was maintained well without loss at last follow-up.

Conclusion: This technique allows assembly of more or less long rigid configurations depending on the injury levels, with satisfactory reduction which is sustained over time. Blood loss is zero with little pain in the postoperative period.


Xavier Semat Jean-Philippe Vivona Marie-Laure Louis Marianne Helix Alexandre Rochwerger Georges Curvale

Purpose of the study: We have had a growing number of revision total hip arthroplasty (rTHA) which have required femorotomy, either planned preoperatively, or required because of difficult extraction of the cemented implant. Few results have been reported in the literature. The purpose of this work was to evaluate late healing of femoral bone and complications.

Material and methods: For this retrospective analysis, we included 43 patients, mean age 66 years. These patients had a femorotomy during rTHA performed from 1997 to 2008. There were 37 revisions in an aseptic context for isolated femoral loosening (n=26), bipolar loosening (n=4), acetabular loosening (n=4), recurrent dislocation, fracture of the femoral stem, and periprosthetic fracture (n=1 each); there were six revisions in septic conditions. Techniques were: femorotomy (n=22), wide trochanterotomy measuring proximally to distally 12 cm, four cortical cuts and one oblique osteotomy to correct valgus. The reconstruction used locked femoral stems (n=17), cemented stems (n=17) and non-cemented stems (n=10). The osteotomies were closed with cerclage or steel wires.

Results: Bone healing was assessed on the plain x-rays of the hip joint at three, six and twelve months. Among the 43 patients included in this analysis, complete data were available for 37. There were 36 cases of successful healing and one case of nonunion on a wide trochanterotomy. The function outcome was assessed a mean three years.

Discussion: Femorotomy remains a difficult technique, sometimes facilitating stem extraction, but with a high risk of morbidity. The morbidity is difficult to evaluate initially, linked more with time to weight-bearing at two months on average. In this small series we nevertheless found few problems with bone healing, even in septic conditions.

Conclusion: Femorotomy remains a valid option when required. It is a difficult technique but provides reliable results in terms of complete healing three months postoperatively.


Christian Renaud Xavier Barreau

Purpose of the study: Vertebroplasty with or without balloons is limited to stabilisation, without restoration of the vertebral endplates despite the risk of complications reported in the literature if this anatomic restoration is not completed before stabilising the vertebral body by cement injection.

Material and methods: Two titanium craniocaudal expansion implants were used to treat 37 patients (18 F, mean age 55years; 19 M, mean age 52 years) via the transpedicular approach for symptomatic traumatic compression fractures of the vertebral body at least 45 days earlier. The reduction was completed by injection of acrylic cement. Anatomic restoration of the vertebral body volume was measured on the 3D CT reconstructions before and after surgery. The superposition methods and calculations of the different parameters (height of the restoration and local vertebral kyphosis) were determined by an independent laboratory: the ENSAM biomechanics laboratory (Paris). Clinical criteria (VAS, Oswestry) were recorded befor and after surgery.

Results: Mean hospital stay was 2.3 days. Pain reduction was significant (70% reduction of mean VAS between the pre- and postoperative values which were unchanged at six months). The 3D images showed the capacity of these implants to restore the anatomic volume and reduce endplate impaction. The traumatic kyphosis angle was reduced on average 26% (maximum 92%) between the pre- and postoperative values.

Discussion: Using implants to maintain the anatomic restoration after fracture reduction appears to be indispensable for cement injection and a key factor for successful treatment of compression fractures of the vertebral body. Millimetric craniocaudal expansion of this new intravertebral titanium implant offers the surgeon greater control for the vertebral fracture. The imaging technique based on 3D reconstruction from pre- and postoperative scans as developed by the ENSAM should allow new standards for the evaluation of the results of surgical treatments for these vertebral fractures.

Conclusion: These preliminary results are very encouraging and should be confirmed at review with one year follow-up. They are part of a broader clinical evaluation project currently being conducted at multiple sites.


Marc-Olivier Falcone Guillaume Wavreille Christian Fontaine Christophe Chantelot

Purpose of the study: This retrospective study evaluated the results, complications and sequelae of 22 free fibular flaps used for bone reconstructions of the limbs assessed at mean 44.4 months.

Material and methods: The tissue loss was the result of trauma in 20 patients and followed cancerology surgery in two. The localisations involved the upper limb in 15 patients and the lower limb in seven. Mean length of bone loss was 11.1 cm. Six injuries required skin cover in addition to the fibular flap. Five patients had had a cement spacer. Fixation methods were: internal fixation (n=14) and external fixation (n=8). Classical vessel anastomosis (one vein, one artery) was used in eight patients and a bridge method (recipient site artery by a fibular artery) in 14 patients.

Results: Bone healing was achieved in 15 patients in 6.7 months on average. Healing was secondary in four patients after corticocancellous grafting. Three flaps failed. Factors significantly associated with favourable healing were: long time from trauma to flap repair, small size of the initial skin opening, first-intention Masquelet, internal fixation, and first-intention cancellous autologous graft. Early postoperative complications of the recipient site included two haematomas and three superficial skin deficiencies. Two graft fractures occurred in one patient and healed after orthopaedic treatment. There were few donor site problems: two early haematomas and two retractions of the flexor hallucis longus. Mean morbidity scores revealed very good results: 1.23/16 with the Point Evaluation System, 93.16/100 for the Karlsson score, and 94.29100 for the Kitaoka score. Globally, the functional assessment of the fibular flap was excellent for three patients, good for eleven, fair for four and poor for one.

Discussion: Our healing rates and durations were not statistically different from earlier reports in the literature. We focused on rigorous preparation in terms of debridement and antibiotic therapy, insertion of a spacer, internal fixation, and complementary first-intention autologous bone graft. In addition, we propose a bridging anastomosis which simplifies the technique and gives the same results as the classical anastomosis methods.


Rachid Chafik Mohamed Madhar Abderrahim El bouanani Mansouri Nadia Saidi Halim Tarik Fikry

Purpose of the study: Injury to peripheral nerves are common. Excessive tension on the suture can be a source of connective tissue reaction and ischemia unfavourable for nerve regeneration. A nerve graft is usually proposed to avoid this problem. The technique we propose was inspired by the one reported by De Medinacelli of which it reproduces solely the principle of distant recruitment.

Material and methods: We used an aponeurotic platform or a hemitendinous platform harvested at the site of the injury. Distant anchorage was sutured with a 7/O thread. The two nerve ends were brought together by rolling the aponeurotic platform around a fine forceps. The section cut was abutted with 10/0 sutures.

Results: This method has been used in 42 patients since 1995 and was preceded by an experimental phase in the rat. It has allowed us to abut nerve ends retracted up to 2.5 cm for large nerve trunks. Preliminary results are globally similar to those of an epiperineural suture or a nerve graft, depending on the case.

Discussion: This technique avoids the complexity of the princeps method of De Medinacelli. It is also much less costly. It also broadens potential indications for direct suture and reduces the need for nerve grafts.


César Vincent-Mansour Anne-Laure Bernat Marc Soubeyrand Véronique Molina Olivier Gagey Charles Court

Purpose of the study: Kyphoplasty was introduced to reinforce the anterior column in osteoporotic vertebral fractures. It can be used for non-osteoporotic fractures. The purpose of this work was to report the clinical and radiographic results of kyphoplasty for non-ostoporotic vertebral fractures.

Material and methods: From December 2005 to August 2008, we followed prospectively 21 patients (12 M, 9 F) mean age 45 years (16–58) treated for thoracolumbar fractures by kyphoplasty in order to reinforce the anterior column. There were 23 fractures (T11 = 2, T12 = 5, L1 = 8, L2 = 4, L3 = 4) Magerl: A1 = 6, A3.1 = 7, A3.2 = 1, B1 = 2, B2 = 7. All patients were assessed preoperatively, postoperatively, and at last follow-up with a visual analogue scale (VAS) and the EIFEL function score. The sagittal CT scans passing through the pedicles and the midline were used to measure: the height of the anterior and posterior walls of the fractured vertebra and the supra and infra vertebrae as well as the kyphosis angle.

Results: Thirteen fractures were treated by kyphoplasty alone; seven by kyphoplasty combined with percutaneous osteosynthesis; three by kyphoplasty combined with open osteosynthesis with decompression because of preoperative neurological deficits. Mean follow-up was 13 months (6–28). There were no postoperative neurological or infectious complications. At last follow-up, the mean VAS was 1.25 (05) and the mean EIFEL 4 (0–12). Preoperatively, mean compression was 40.9% (6.2–81.4) for the anterior column and 16.7% (0–60.2) for the posterior column. Postoperatively the respective values were 22.8% (5.1–69.3) and 12.3% (−12 to 72.6) for a mean correction of 46.2% for the anterior column and 14.3% for the posterior column. At last follow-up, compression was respectively 26.1% and 7.9%. The vertebral kyphosis was 16.3 (6–16.3) preoperatively and 9.1 (3–4) postoperatively (mean correction 8.7). At last follow-up, vertebral kyphosis was 9.1 (1.7–28.3).

Discussion: Kyphoplasty allows satisfactory restoration of vertebral height without loosing short-term correction. For us, kyphoplasty should be associated with posterior fixation in patients with posterior injury. For neurological lesions, kyphoplasty associated with decompression and posterior fixation avoid the need for complementary anterior procedures.


Sybille Facca Reeta Ramdhian Monica Diaconu Alexandre Pélissier Stéphanie Gouzou Philippe Liverneaux

Purpose of the study: Fractures of the metacarpals are common injuries generally observed in young males. Nailing, either with a centromedullary configuration or intermetacarpal construction is generally proposed. The nailing procedure nevertheless has its drawbacks: fracture instability, secondary displacement, pin migration, infection, requirement to remove material, injury to the cutaneous dorsal branch of the ulnar nerve, and most importantly, immobilisation for several weeks which is a major inconvenience for these young active patients. In this context, we wanted to compare two fixation systems: a locked plate versus centromedullary nailing.

Material and methods: This was a retrospective comparison of consecutive patients from September 2007 to December 2008. The series included 39 cervical fractures of the fifth metacarpal in 39 patients aged 31 years on average. The first 19 patients were treated with a locked plate (Médartis®) (group A) and the 20 others with descending centromedullary nailing (group B). In group A, a dorsal approach respecting the dorsal cutaneous branch of the ulnar nerve was used. The technique consisted in insertion of distal locking screws enabling fracture reduction on the plate. No postoperative immobilisation was proposed and rapid mobilisation was encouraged. In group B, classical centromedullary nailing was performed with immobilisation with a short Thomine brace and syndactylisation of the last two fingers. Outcome was based on objective criteria (Jamar® force, joint motion, duration of sick leave) and subjective assessment (DASH, VAS).

Results: Mean follow-up was 12 months in group A and 8 months in group B. Depending on the type of fracture, plates with different shapes and lengths were used in group A; a single pin was used in group B (16/10 or 20/10). Secondary displacement was more frequent in group B, but the results in recovered motion were better in group B. The only parameter better in group A was length of sick leave; four patients in group A underwent reoperation to remove the plate and for tenoarthrolysis. In all, the outcomes for cervical fractures of the fifth metatarsal were better in group B.

Discussion: Our preliminary results in group A show lesser complications and earlier return to work compared with better motion at last follow-up in group B. Centromedullary nailing remains the better treatment for cervical fractures of the fifth metatarsal. The extra cost of the plates does not appear to be warranted for the treatment of neck fractures of the fifth even though the patient can resume occupational activities earlier.


Philippe Adam Matthieu Ehlinger Gilbert Taglang Thomas Moser Jean-Claude Dosch François Bonnomet

Purpose of the study: Computed tomography is recommended for the preoperative work-up of joint fractures as it allows an optimisation of the access as a function of the injury. During the operation, 2D radiographic or fluoroscopic controls are still widely used. After one year’s experience, we evaluated the potential pertinence of using 3D reconstructions intraoperatively with a mobile isocentric fluoroscope (iso-C-3D).

Material and methods: All operations for which the amplifier was used were collected prospectively. The type of fixation as well as the details of the installation and measures taken intraoperatively were noted.

Results: At one year, intraoperative 3D reconstructions were made during 48 operations in 47 patients: fracture of the calcaneum (n=13), thoracolumbar spin (n=12), acetabulum (n=11), tibial condyles (n=9), odontoid (n=2), pelvis (n=1). The installation was habitual for the calcaneum and odontoid fractures. For the other localizations, use of a carbon plateau table facilitated good quality imaging for spinal and tibial condyle fractures; a carbon orthopaedic table was useful for acetabulum and pelvis fractures. With the intraoperative 3D reconstruction the surgeon was able to check the freedom of the canal after reduction and fixation. For the calcaneum fractures, reduction of the thalamic fragment was revised in one patient; in another, an intra-articular screw was replaced. One intra-articular screw stabilizing the posterior wall was also changed during an acetabulum fixation.

Discussion: During our first year of use, 3D reconstruction intraoperatively has allowed us to avoid three early reoperations (for two calcaneums and one acetabulum). Classical 2D imaging of these two localizations is difficult to interpret because of the spherical form of the hip joint and, for the calcaneum, the difficulty in obtaining quality retrotibial images. Quality images requires specific installation, limiting interference with metallic supports.

Conclusion: The results we have obtained in our first year of use of the ISO-C-3D amplifier has led us to generalise its use for percutaneous fixation procedures involving the acetabulum and the calcaneum.


Jérome Diligent Danièle Bensoussan Elie Choufani Armelle Breton Laurent Galois Didier Mainard

Purpose of the study: Nonunion, which is a biological failure, requires revision, usually an aggressive operation. Haematopoietic bone marrow contains colony forming unit fibroblasts (CFU-F) which could favour bone healing. The purpose of this work was to determine whether a minimally invasive procedure, injection of CFU-F into the nonunion space, could favour bone healing without further procedure.

Material and methods: Our series included 43 patients: 36 male and 7 female, mean age 39.9 years. Forty-seven atrophic and aseptic nonunions of long bones were treated with percutaneous injection of concentrated autologous bone marrow: 27 tibias, 17 femurs, 3 humeri. Bone marrow was harvested from the posterior iliac crests (346 ml) then centrifuged to keep the leuko-platelet fraction (78 ml). This concentrate was injection into the nonunion space under radioscopic guidance. Efficacy was assessed on the basis of clinical criteria (complete pain-free weight-bearing, absence of contention, absence of mobility) and on radiographic criteria (healing of 3/4 corticals).

Results: Thirty nonunions healed: 19 tibias (70%, 11 femurs (65%) and 0 humerus. Mean time to healing was 5.9 months (2.4–15.6). Factors of poor prognosis were: smoking, alcohol, diabetes, corticosteroids, radiotherapy, history of sepsis (p=0.01). Early grafting increased the chances of success (p=0.04). Age, initial skin opening, type of fixation did not have a significant impact on healing. The number of CFU-F had an effect on the rate of healing.

Discussion: This technique is effective for the treatment of nonunion of the lower limb, allowing bone healing in two thirds of the cases with a minimally aggressive procedure. The method is easy to perform but requires a rigorous technique for the different phases of puncture, concentration and reinjection. Nonunions unresponsive to conventional methods, and thus corresponding to multifactorial problems, probably constitute the limitation of this method. Cell expansion or differentiation techniques could be helpful in improving the success rate but at the present time the osteogenic potential of these cells remains to be elucidated as a function of their stage of maturation.

Conclusion: Percutaneous grafts of concentrated autologous bone marrow can be a useful contribution to the therapeutic armamentarium for nonunion. Morbidity is low and the method does not compromise future options. It can be proposed as a first-intention solution for the treatment of long bone nonunion.


RL Jayasuriya RA Hannon R Eastell I Stockley JM Wilkinson

Measurements of biochemical markers of bone turnover have been explored as a diagnostic tool for the detection of osteolysis after THA, but their predictive value in individual subjects has been poor. One explanation for this low diagnostic utility is that the mechanism of bone resorption in osteolysis may be different to that occurring in other high bone turnover states, such as osteoporosis, where these markers were principally developed. The aim of this study was to examine the role of the biomarkers urinary ααCTX-I and serum CTX-MMP, that are released in pathological rather than physiological bone turnover states, for detecting periprosthetic osteolysis in a case control study of 23 subjects with osteolysis and 26 controls. All samples were collected between the hours of 0800 and 1000 following an overnight fast, and were assayed using standard techniques. The demographic characteristics of the subjects in both groups were similar. Serum CTX-MMP was greater in the osteolysis versus the control group (P=0.001). Urinary ααCTX-I was similar between osteolysis and control groups (P> 0.05). A cut-off value of 5.50ng/mL CTX-MMP had a sensitivity of 91% (95% CI: 72 to 99) and specificity of 69% (48 to 96) detecting osteolysis (P=0.001). The same cut-off had a sensitivity of 100% (100 to 100) and specificity of 63% (44 to 79) for detecting femoral osteolysis (P=0.0004), and a sensitivity of 89% (65 to 98) and specificity of 58% (39 to 75) for identifying pelvic osteolysis (P=0.014). Serum CTX-MMP shows promise for further investigation as a sensitive bio-marker for detecting periprosthetic osteolysis.


RL Jayasuriya SC Buckley AJ Hamer RM Kerry I Stockley MW Tomouk JM Wilkinson

In this 2-year randomised clinical trial we examined whether cemented femoral prosthesis geometry affects the pattern of strain-adaptive bone remodelling in the proximal femur after THA. 128 patients undergoing primary THA were randomised to receive a Charnley (shape-closed, no taper), Exeter (force-closed, double-tapered) or C-stem (forced-closed, triple-tapered) prosthesis. All received a cemented Charnley cup. Proximal femoral BMD change over 2 years was measured by DXA. Urine and serum samples were collected at pre-operative baseline and over 1 year post-operatively. N-telopeptides of type-I-collagen (NTX) was measured in urine as a marker of osteoclast activity and Osteocalcin (OC) in serum as a maker of osteoblast activity. Clinical outcome using the Harris and Oxford hip scores, and prosthesis migration measured using digitised radiographs (EBRA-Digital) were measured over 2 years. The baseline characteristics of the subjects in each group were similar (P> 0.05). Decreases in femoral BMD were observed over the first year for all prosthesis designs. Bone loss was greatest (14%) in the proximal medial femur (region 7). The pattern and amount of bone loss observed was similar between all prosthesis designs (P> 0.05). Transient rises in both osteoclast (NTX) and osteoblast (OC) activity also occurred over year 1, and were similar in pattern in the 3 prosthesis groups (p> 0.05). All prostheses showed migration patterns that were true to their design type and similar improvements in clinical hip scores were observed over the 2 year study. Differences in the proposed mechanism of load transfer between prosthesis and host bone in force-closed versus shape-closed femoral prosthesis designs in THA are not major determinants of prosthesis-related remodelling.


H Wynn Jones J Wimhurst R Macnair B Derbishire N Chirodian A Toms J Cahir

Introduction: Although good mid-term results have been reported with some metal on metal hip replacements, reported complications due to metal on metal (MOM) related reactions are a cause for concern. We have assessed the clinical outcome and MRI metallic artefact reduction sequence (MARS) findings in a consecutive series of patients with a large head metal on metal hip replacement.

Methods: 62 ASR XL Corail THRs and 17 ASR resurfacings were performed at our hospital between 2005 and 2008. All patients were reviewed and assessed with an Oxford hip score (OHS), a plain radiograph and a MRI imaging was obtained on 76 (96%) hips. Implant position was assessed using Wrightington cup orientation software.

Results: At a mean follow up of 32 months, 9 (15%) ASR XL Corail THRs, and 2(12%) ASR resurfacings had been revised. 10 revisions were performed for MRI confirmed MOM related pathology. Histology confirmed a MOM reaction in all 10 cases.

Of the 76 hips that were MRI scanned, 27 (36%) had typical features of a MOM reaction. These were classified as mild in 10 (13%), moderate in 13 (17%) and severe in 4 (5%).

78 patients completed an OHS and the mean score was 21. The mean OHS was 29 pre-operatively in those that had been revised, 25 in patients with abnormal MRI findings and 20 in those with a normal MRI. 10 patients with abnormal MRIs had a near perfect OHS (15 or less)

Conclusions: The ASR XL Corail THR has an unacceptably high early failure rate. MARS MRI is able to detect metal debris related soft tissue pathology around metal on metal THRs. These lesions are sometimes asymptomatic. We suggest that MARS MRI evaluation should form part of the routine evaluation of all metal on metal THRs, and in particular of this implant.


RE Andrews A Gartland JM Wilkinson

One possible mechanism by which metal-on-metal hip resurfacing (MOMHR) may be associated with prosthesis loosening, periprosthetic fracture, and femoral neck narrowing is through an increase in bone resorption by osteoclast cells. Whilst it is known that metal ions such as cobalt (Co) and chromium (Cr) ions (that are elevated locally and systemically after MOMHR), may affect osteoblast and macrophage activity in-vitro, little is known about the effect of these ions on osteoclasts. We examined whether these ions have an adverse effect on human peripheral blood derived osteoclasts at levels that are clinically relevant after MOMHR. Peripheral blood mononuclear cells from healthy donors were seeded onto dentine wafers, and treated to transform them into osteoclasts using standard techniques in the presence of various clinically relevant concentrations of Co2+, Cr3+, and Cr6+. After 3 weeks of culture osteoclast number and resorption pit formation was quantified using histological techniques. All 3 metal ions had a dose-dependent effect on both osteoclast formation and resorption activity. At ion levels found in serum after MOMHR, an increase in osteoclast formation and bone resorption was found, but at higher levels found in synovial fluid, osteoclast cell proliferation and resorption activity was decreased, likely due to a direct toxic effect of the ions on the cells (Figure 1). Cr6+ was more toxic than the other ions at higher concentrations. Our data suggest that metal ion release following MOMHR may increase osteoclast activity systemically that might have a deleterious effect on general and local bone health, and may contribute to the observed bone related complications of MOMHR.


T Ibrahim M Ghazal Aswad JJ Dias CN Esler AR Brown

Introduction: To report the 11-year follow-up of patients of contaminated femoral heads donated at primary total hip replacement from a cohort study published in 2004.

Methods: Of the 440 donors, 266 patients (61%) were still alive at a mean of 11.7 years post primary total hip replacement and 170 patients (64%) agreed to review. The patients had either a positive or negative culture from their donated femoral head at primary total hip replacement. The Oxford hip score, European Quality of Life (EuroQOL) questionnaire, rates of complication and revision surgery were used as outcome measures.

Results: At long-term follow-up, the Oxford hip score was not different between the positive (mean = 36, standard deviation = 12.3) and sterile (mean = 39, standard deviation = 10.9) groups (p = 0.40). The EuroQOL questionnaire was also not different between the positive and sterile groups. There was no statistically significant difference in the rate of complications (p = 0.93) and revision surgery (p = 0.11) of the age-matched patients whose femoral heads had a positive culture compared with those whose femoral heads were sterile.

Discussion: The results of this 11-year follow-up of contaminated donated femoral heads cohort study were similar to those at short-term follow-up. Culture results of donated femoral heads play no significant role in predicting failure of primary total hip replacement in the donor at long-term follow-up.


JR McArthur M Costa DR Griffin SJ Krikler N Parsons GT Pereira U Prakash S Rai PR Foguet

Introduction: Pain and mass lesions around hip resurfacing are reported with increasing frequency. The aetiology is unknown but reaction to metal wear debris and mechanical impingement have both been suggested. We are aware of a group of our patients with significant pain following resurfacing. We sought to correlate metal ion levels with X-ray findings and any local soft tissue reaction around the prosthesis.

Methods: Patients with significant groin pain following hip resurfacing were identified from routine clinics. Blood was tested for cobalt and chromium levels using inductively coupled mass spectrometry in all patients. Cup abduction angle and femoral stem version were estimated from plain radiographs. Patients underwent ultrasound scan (USS) of the affected hip joint. Bilateral prostheses were excluded to avoid confounding.

Results: 47 unilateral painful hip resurfacings (24 female) were identified. USS was performed in 42 patients and was abnormal in 25 (15 female). Abnormalities ranged from simple joint effusion with or without synovial thickening, through to cystic masses in the posterior joint and solid masses related to the ileopsoas tendon similar to the appearances previously described in pseudotumours.

A two sample t-test demonstrated cobalt and chromium ion levels were significantly higher in patients with abnormalities on USS (p=0.038, p=0.05 respectively), patients with normal USS were more likely to have a retroverted femoral component (p=0.01).

Discussion: We describe two groups of patients with a painful hip resurfacing: those with raised metal ions and local soft tissue reaction, and those with lower metal ions and no soft tissue reaction. The retroverted stems in the second group could cause an iatrogenic cam-type impingement. Metal ion levels are useful to guide further imaging. Raised levels should prompt investigation for a soft tissue abnormality with either USS or MRI, lower levels suggest investigation should look for mechanical impingement with imaging such as CT.


G. Grammatopoulos H. Pandit A. Taylor D. Whitwell S. Glyn-Jones R. Gundle P. McLardy-Smith D.W. Murray H.S. Gill

Introduction: Metal-on-metal-hip-resurfacing-arthroplasty (MoMHRA) has been associated with the development of inflammatory pseudotumours(IP), especially in females. IPs have been linked to wear debris, which can be related to metal-ion blood levels. Acetabular component position has been shown to influence wear. We have identified an optimum component orientation minimising IP risk around an inclination/anteversion of 40°/20°±10°. Our aim was to see if this optimal position results in lower metal ions and to identify the boundary of an optimal placement zone for low wear.

Methods: A cohort of 104 patients(60M:44F) with unilateral MoMHRA was studied. Blood tests were obtained at a mean follow up of 3.9 years and serum Co/Cr levels were measured(ICPMS). High metal ion concentrations were defined as Co> 4.1ppb and Cr> 5.2ppb. Radiographic cup inclination/anteversion were measured using EBRA. The differences in ion levels between different orientation zones were investigated. Three orientation zones were defined centered on 40°/20°: Z1-within ±5°, Z2-outside ±5°/within ±10° and Z3-within ±10°.

Results: There was a wide range of cup placements. Females had significantly (p< 0.001) smaller components(mean:51, 44–60) than males(mean: 56, 52–64). Cr levels, but not Co, were higher in females(p=0.002) and those with small femoral components(< 50mm, p =0.03). Patients with cups within Z1 (n=13) had significantly lower Co(p=0.005) and Cr(p=0.001). Males with cups within Z3(n=27) had lower ion levels in comparison to those outside, which were significantly lower for Co(p=0.049) but not Cr(p=0.084). Females had similar ion levels within and out of Z3(Cr/Co: p=0.83/0.84). Co levels were significantly lower in Z1(n=13) in comparison to Z2(n=33)(p=0.048) but Cr levels were not different (p=0.06).

Discussion: MoMHRA cups placed within ±5° of the optimum(40°/20°) had significantly lower metal ions indicating lower wear within this narrow zone. This safe zone, could extend to ±10° for males only. The narrower safe zone coupled with smaller components implanted are possible factors contributing to the increased IP incidence seen in females.


G. Grammatopoulos H. Pandit A. Taylor D. Whitwell S. Glyn-Jones R. Gundle P. McLardy-Smith H.S. Gill D.W. Murray

Introduction: Metal on metal hip resurfacing arthroplasty(MoMHRA) is an alternative option to THR in the treatment of young adults with OA. A recognised MoMHRA complication is the development of an inflammatory pseudotumour(IP). Diagnosis is made with the aid of US and/or MRI. To-date, no radiographic indication of the presence of IP has been identified. Neck thinning is a recognised phenomenon in MoMHRA hips not associated with any adverse clinical events. Its pathogenesis is considered multi-factorial. Our aim was to establish whether excessive neck narrowing is associated with the presence of a pseudotumour.

Methods: Twenty-seven hips (26 patients) with IP confirmed clinically, radiologically, intra-operatively and histologically were matched for sex, age, pre-operative diagnosis, component size and follow-up with an asymptomatic MoMHRA cohort (Control n=60). For all patients, prosthesis-neck-ratio(PNR) was measured on plain AP pelvic radiographs post-operatively and at follow-up as previously described and validated.

Results: All IP patients (4M:23F) and all (12M:48F) but two controls had a posterior approach at the time of MoMHRA. Post-operatively, there was no difference in the PNR between the two groups (p=0.19). At an average follow up of 3.5 years (range:0.7–8.3), IP patients(mean 1.26, 1.10–1.79) had a significantly higher (p< 0.0001) PNR in comparison to their controls(mean 1.14, 1.03–1.35). Greater neck narrowing occurred in both genders. IP necks had narrowed by an average of 8% (range:3–23). The degree of neck narrowing was correlated with length of survival of implant (p=0.001).

Discussion: This study shows a strong association between IP and neck narrowing. Processes such as impingement and increased wear are considered to be involved in the pathogenesis of both IP and neck narrowing. Furthermore, the presence of an IP, could lead to altered vascularity via a mass effect and further contribute to neck narrowing. Neck narrowing in symptomatic MOMHRA patients should alert surgeons of the possible presence of IP.


L Rahman SK Muirhead-Allwood

Introduction: Excellent early and medium term results have been reported for hip resurfacing. This is a minimum 5 year clinical outcome review of the resurfacings performed by a single surgeon in an independent series.

Methods: There were 329 resurfacings (302 patients). The mean follow-up is 6.6 years (5 to 9.2). 2 patients were lost to follow-up and 6 have died due to unrelated causes. The mean age at the time of surgery was 56.0 years (28.2 to 75.5). Mann-Whitney U-test was used to analyse change in hip scores, and survival analysis was performed using the Kaplan-Meier analysis using SPSS statistical software package.

Results: The mean Harris Hip Score was 51.3 (7 to 91) pre-operatively and 94.3 (24 to 100) postoperatively (p< 0.001). The mean Oxford hip scores was 38.3 (16 to 60) pre-operatively and 15.9 (12 to 46) postoperatively (p< 0.001). The mean Western Ontario and McMaster Universities Osteoarthritis Index score was 47.9 (5 to 96) pre-operatively and 6.9 (0 to 58) postoperatively (p< 0.001). The University of California Los Angeles activity scale was 4.7 (1 to 9) pre-operatively and 7.5 (3 to 10) post-operatively (p< 0.001). Mean satisfaction at the latest follow up was 9.3 (3–10) out of 10.

There were ten revisions. Kaplan-Meier analysis showed survival of 96.5% (95% confidence interval 94.7 to 98.4) at 7 years taking revision for any cause as the end-point. There was a 3.9 times higher failure rate in women compared to men.

Discussion: Medium term results of hip resurfacing in this independent series are excellent and are comparable to those from the pioneering centre. Failure rates are significantly higher in women compared to men. Long term follow up results are still awaited, however careful consideration should be made when selecting patients for hip resurfacing particularly in women.


McWilliams A. Grainger A. O’Connor P Ramaswamy R. White D. Redmond A.C. Stewart T. Stone M.H.

Introduction: Leg length inequality (LLI) following arthroplasty, though often asymptomatic, can be cause for considerable morbidity and has increasing medicolegal consequences.

There are various methods of quantifying leg length inequality on plain AP radiograph. The aim of this study is to review the established practice in the measurement of leg length inequality and compare it to two methods used locally.

Methods: This is a retrospective study assessing the radiographs of 35 patients with a mix of native, unilateral and bilateral total hip arthroplasty. Two methods of measuring leg length inequality were prominent in the literature, the Woolson method and the Williamson method. A further two methods are used locally. Measurements for all four techniques were made by two senior consultant radiologist to on the trust PACS to assess inter and intra observer variability. Data analysis was performed using SPS 16 to produce intraclass correlation co-efficient (ICC) and Bland Altman plots.

Results: ICC for all methods in the measurement of LLI is excellent (≥0.90). The repeatability ICC for the four methods is; Woolson 0.65, Williamson 0.87, Direct 0.96 and the Leeds method 0.95.

Discussion: This study demonstrates that all four methods have excellent correlation; however the repeatability is better for the Direct and the Leeds methods than the two that are more widely used in the literature. While the Direct measurement is able to give an overall measurement for the leg length inequality, the Leeds method is able to distinguish between any inequality due to cup malpostion and stem malposition. It is therefore of particular value in the assessment of bilateral or revision arthroplasty and the audit of practice.


B Purbach B M Wroblewski P D Siney P A Fleming P R Kay

Introduction:. The C-Stem in its design as a triple tapered stem, is the logical development of the original Charnley flat-back polished stem. The concept, design and the surgical technique cater for a limited slip of the stem within the cement mantle transferring the load more proximally.

Method: Five thousand two hundred and thirty three primary procedures using a C-stem have been carried out since 1993. We reviewed all 621 cases that had their total hip arthroplasty before 1998.

Results:. Sixty nine patients (70 hips) had died and 106 hips had not reached a ten-year clinical and radiological follow-up and had not been revised. In 22 hips, the stem had been changed before the 10 year follow-up, with infection, dislocation and loosening of the cup being the reasons for revision. None of the stems were loose.

The remaining 423 hips had a mean follow-up of 11 years (range 10 – 15 years). There were 216 women and 173 men, and 34 patients had bilateral LFAs. The patients’ mean age at surgery was 53 years (range 16 – 83 years). Thirty eight hips had been revised at the time of review. The reasons for revision were infection in 5: dislocation in 2: loose cup in 28: wear in 2 and 1 for meralgia paresthetica where the stem was found to be well fixed. In 1 case which had not been revised there was radiological loosening of the stem in a patient with Gaucher’s disease.

Discussion: With only 1 stem radiologically loose and no revisions for stem loosening the clinical results are very encouraging and they support the concept of the Charnley cemented low friction arthroplasty, but place a demand on the understanding of the technique and its execution at surgery.


RJ Underwood PM Cann K Ilo CR Wagner J Skinner J Cobb M Porter S Muirhead-Allwood A Hart

Introduction: The London Implant Retrieval Centre (LIRC) was founded to investigate the high incidence of unexplained failures of Metal-on-Metal (MoM) hips. A multidisciplinary team analyse the failed hips, investigations include CT and MRI scans, blood and synovial fluid tests, wear measurements, X-rays and clinical data from the explanting surgeons.

Wear measurements of 100 explanted hips have been carried out on a Taylor Hobson 365 Roundness Machine using the LIRC Wear Protocol. It was found that 50% of explanted cups were wearing less than 5 μm/year and 60% of components were wearing less than 10 μm/year. Wear tests on hip joint simulators predict wear rates between 2 and 8 μm/year. However, 6% of cups are wearing faster than 100 μm/year, with 16% of cups have wear patches deeper than 100 μm and that 4% have a wear patch deeper than 300 μm.

Discussion: This paper considers the common characteristics of components in this very high wearing category. Engineering parameters such as head/cup clearance, surface finish, form errors and head cup contact conditions are investigated. This is correlated with clinical data and other results from the LIRC.

Cup position is an important factor, all of the high wearing components are outside the Lewinick’s Box, however it is shown that mal position is does not always lead to extreme wear. Further analysis is taking place to calculate the size of the contact patch between head and cup (based on patient data and biomechanics) and the proximity of the contact patch to the edge of the cup.

Conclusion: The study of explanted components shows that 6% exhibit extreme wear, and although several “risk” factors can be identified, it is not clear why only a proportion of these components show extremely high wear rates. This is the subject of current investigation.


M Ockendon JE Oakley NM Graham

Introduction: The Optiplug® bio-absorbable cement restrictor, marketed by Biomet inc., is manufactured from ‘PolyActive’ – a polymer of poly(ethylene glycol) and butylene terephthalate. Biodegradation is thought to be by a combination of hydrolysis and oxidation.

The potential benefit – eliminating the need for restrictor removal at future revision surgery – led to Optiplug becoming our cement restrictor of choice over the last 5 years.

Anecdotally we have seen marked osteolysis around the distal cement mantle in a number of follow up radiographs in these patients. To date we have not seen an associated peri-prosthetic fracture.

We undertook a retrospective, radiographic study to determine incidence, severity and progression of this osteolysis over the first 5 years of follow up.

Method: 100 patients for whom 5 year follow up had been undertaken were identified from the departmental database. Patients with loose prostheses and or infection were excluded as were those who had undergone revision surgery.

Radiographs from the immediate post operative period, twelve months and five years follow up visits were identified and reviewed.

Osteolysis was quantified by calculating the ratio of maximum medullary diameter to the overall cortical diameter of the bone. Comparison was made over time and, where radiographs allowed, to the immediately adjacent femur.

Results: 87% of radiographs showed greater than 10% thinning of the cortex at 1 year cf. immediate post op. 5 cases showed greater than 33% thinning. These changes do not appear to progress or regress significantly between 1 and 5 years.

Discussion: While marked osteolytic changes appear to be uncommon, some degree of cortical thinning was almost universal in this series. The zone immediately distal to the cement mantle is commonly involved in peri-prosthetic fractures. Any weakening in this area is undesirable.


S Panchani D Melling JD Moorehead P Carter SJ Scott

Introduction: The aim of this study was to compare hip movement between normal subjects and patients with a large Metal on Metal hip replacement, undertaking the task of retrieving an object from the floor.

Methods: An electromagnetic tracker was used to measure movement as subjects retrieved an object with flexed hips and straight knees. Measurements were taken from a control group of 10 subjects with bilaterally normal hips, and 10 subjects with unilateral hip replacement. Sensors were attached over the iliac crest and the mid-shaft of the lateral thigh. Data was collected as each subject repeated the movement 3 times. The tracker recorded data at 10 hertz, with an accuracy of 0.15 degree.

Results: For the normal group the mean hip flexion was 90.8 degrees (SD 20.1). For the arthroplasty group the mean flexion on the normal and operated sides were 74.0 (SD 21) and 72.7 degrees (SD 21) respectively. This was not significant (P= 0.83). However there was a significant difference in hip movement between the operated hips and those in the normal control group (P= 0.03).

For the bilaterally normal group the mean hip rotation was 2.9 degrees internal (SD 11.8). For the arthroplasty group the mean rotation on the normal and operated sides were 9.4 degrees external (SD 9.5) and 6.9 degrees internal (SD 13.9) respectively. In this group there was a significant difference between the normal and operated side (P= 0.02).

Discussion: This study has shown that patients with a unilateral hip replacement have no significant flexion difference between hips, when retrieving an object from the floor. However there was a significant difference compared to a control group with normal hips. A significant difference was also observed when comparing the rotation of an operated hip joint to the contra-lateral normal hip in the same individual.


GER Thomas DJ Simpson A Taylor D Whitwell CLMH Gibbons R Gundle P Mclardy-smith HS Gill S Glyn-jones DW Murray

Introduction: The use of highly cross-linked polyethylene (HXLPE) is now commonplace for total hip arthroplasty, however there is no long-term data to support its use. Hip simulator studies suggest that the wear rate of some types of HXLPE is ten times less than conventional polyethylene (UHMWPE). The outcomes of hip simulator studies are not always reproduced in vivo and there is some evidence that HXLPE wear may increase between 5 and 7 years.

Method: A prospective double blind randomised control trial was conducted using Radiostereometric Analysis (RSA). Fifty-four subjects were randomised to receive hip replacements with either UHMWPE liners or HXLPE liners. All subjects received a cemented CPT stem and uncemented Trilogy acetabular component (Zimmer, Warsaw, IN, USA). The 3D penetration of the head into the socket was determined to a minimum of 7 years.

Results: The total liner penetration was significantly different at 7 years (p=0.005) with values of 0.33 mm (SE 0.05 mm) for the HXLPE group and 0.55 mm (SE 0.05 mm) for the UHMWPE group. The steady state wear rate from 1 year onwards was significantly lower for HXLPE (0.005 mm/yr, SE 0.007 mm/yr) than for UHMWPE (0.037 mm/yr, SE 0.009 mm/yr) (p=0.007). The direction of wear was supero-lateral.

Discussion: We have previously demonstrated that the penetration in the first year is creep-dominated, from one year onwards the majority of penetration is probably due to wear. This study confirms the predictions from hip simulator studies which suggest that the wear rate of this HXLPE approaches that of metal-on-metal and ceramic-on-ceramic articulations. HXLPE may have the potential to reduce the need of revision surgery, due to wear debris induced osteolysis. It may also enable surgeons to use larger couples, thus reducing the risk of impingement and dislocation.


Kumar R Malhotra S Bhan

Background: Joint replacements are being performed on ever younger patients at a time when average expectancy of life is continuing to rise. Any reduction in the strength and mass of periprosthetic bone could threaten the longevity of implant by predisposing to loosening and migration of prosthesis, periprosthetic fracture and problems in revision arthroplasty.

Aims & Objectives: This study aims to analyse and compare prospectively the femoral periprosthetic stress-shielding around 4/5th and 1/3rd porous coated cementless femoral stems in patients undergoing unilateral cementless total hip replacement done using DEXA scan by quantifying the changes in bone mineral density around femoral component.

Material & Method: Femoral periprosthetic bone mineral density was measured in the seven Gruen Zones with DEXA scan at 2 weeks, 1 years and 2 years after surgery in 60 patients who had undergone unilateral cementless total hip replacement, of which 30 patients had been implanted with 4/5th porous coated stems and other 30 patients with 1/3rd porous coated stems.

Results: At both one and two years postoperatively, bone loss due to stress-shielding was seen in both stems with maximum loss in zone VII and minimum in zone III, IV, V. The maximum mean percentage bone mineral density loss in 4/5th porous coated stems in zone VII was 16.03% at one year and 22.42% at 2 years as compared to loss of 10.07% and 16.01% in 1/3rd porous coated stems. Increased bone loss was seen in patients who had larger diameter stem (> 13.0 mm) and in patients with low bone mineral density in the unoperated hip.

Conclusion: Bone loss as a result of stress-shielding is more pronounced in 4/5th porous coated stems as compared to 1/3rd porous coated stems.


P Avery M Walton G Rooker M Gargan B Squires R Baker G Bannister

Introduction: We report on the long-term follow up of a previously published randomised controlled trial comparing Hemiarthroplasty (HEMI) and total hip arthroplasty (THA) for the treatment of intracapsular fracture neck of femur.

Methods: In this prospectively randomized study, 81 patients who had been mobile and lived independently and who sustained a displaced fracture of the femoral neck were randomized to receive either a fixed acetabular component THA or HEMI. The mean age of the study group was 75 years at fracture. All patients received the same cemented collarless tapered femoral stem and all procedures were performed through a transgluteal approach. Patients were followed up with radiographs, Oxford hip score (OHS), SF-36, Euroqol and their walking distance.

Results: At a mean follow-up of 8.6 years (7.18 to 10.27), 19 HEMI patients and 27 THA were alive (p=0.042). The mean walking distance of patients after HEMI was 600m and the OHS 21. After THA, the mean walking distance was 1200m and the OHS was 22. Both groups had a deterioration of their OHS over time. There were no significant differences between the groups with respect to both physical and mental component SF-36 scores and Euroqol visual analogue scores.

Of the survivors four of the HEMI group were revised to total hip arthroplasty. One patient had been revised in the THA group. Radiographically six of seven patients in the HEMI group had evidence of acetabular erosion and 13 of 15 patients in the THA group had a lucency around their acetabular component.

Discussion: Patients with THA walked further and survived longer. After a mean of nine years follow up there was no difference with respect to function as measured by OHS, Euroqol and SF-36 scores.


AJ Hart K Davda F Lali J Skinner B Sampson

Introduction: Local problems of metal on metal (MOM) hip arthroplasty such as pseudotumours, neck thinning and osteolysis maybe related to concentrations of cobalt and chromium ions in the synovial fluid. There is little reported on these values. Our aim was to determine the range of metal ion levels in synovial fluid, and to investigate the relationship between these samples and simultaneous blood samples.

Methods: Synovial fluid and whole blood samples were taken from 30 consecutive patients at the time of revision surgery for a painful MOM hip. Aspirated fluid was not visibly contaminated with blood. Impants were in situ for a mean period of 31 months. All had normal renal function. Samples were analysed using ICP mass spectrometry and compared with 10 samples from patients without implants.

Results: The mean (and range) of synovial fluid metal ion levels were 1965 ug/l (30 to 13618) and 6265 ug/l (11 to 81630) for Cobalt and Chromium respectively. There was a good correlation between synovial and blood levels for both cobalt (R=0.65, p = 0.0001) and chromium (R = 0.59, p = 0.006).

Discussion and Conclusion: Metal ions in synovial fluid from MOM hips are generated from wear of the bearing surfaces, the correlation with blood metal ion levels, shown in this study, suggest that blood levels may be used as surrogate marker for hip wear rate. Our range of synovial fluid metal ion levels may be useful for those conducting in vitro studies on the biocompatibility of MOM hips.


E Shears CW McBryde JN O’Hara PB Pynsent

Introduction: A proposed benefit of hip resurfacing is straightforward revision. This study assesses the outcome of revision in a large series of failed resurfacings.

Methods: A consecutive series of 84 revisions of metal-on-metal hip resurfacings was analysed. The cohort consisted of 51 (61%) women and 33 (39%) men with a mean age of 48.0 years (range: 15.1–75.3 years) at primary resurfacing. The underlying diagnosis was primary osteoarthritis in 40 (48%) patients, developmental dysplasia of the hip in 13 (15%), avascular necrosis in 9 (11%) and slipped upper femoral epiphysis in 7 (8%).

Mean patient age at first revision was 50.8 years (range: 18.4–75.9 years), at a median of 1.8 years (25th percentile 0.03 years, 75th percentile 4.6 years) after the primary operation. 29 (35%) resurfacings were revised for aseptic loosening, 23 (27%) for periprosthetic fracture, 8 (10%) for component malalignment, 8 (10%) for pain alone, 4 (5%) for infection, 4 (5%) for avascular necrosis and 4 (5%) for instability.

Results: At a mean follow-up of 4.6 years (range: 1.0–8.2 years) after the first revision, 10 (12%) of the revised hips had undergone a second revision procedure. 6 men and 3 women required re-revision (data not available for 1 patient). The reasons for the first revision were acetabular malalignment (n=2), femoral neck fracture (n=2), aseptic loosening (n=2), avascular necrosis (n=1), instability (n=1) and pain alone (n=1). The second revision was required at a mean of 3.4 years (range: 0.4–6.3 years) after the first.

Discussion: This study suggests that revisions of hip resurfacing for acetabular malalignment may be at increased risk of subsequent re-revision (2 of 7 patients, 29%). Revision for other causes appears to have better survival in the short to medium term.


RP Baker TCB Pollard S Eastaugh-Waring GC Bannister

Introduction: We compared the eight- to ten-year clinical and radiological results of the metal-on-metal Birmingham hip resurfacing (BHR) with a hybrid total hip arthroplasty (HYBRID) in two groups of 54 hips, previously matched for gender, age, body mass index and activity level.

Method: Patients were followed up in outpatients and function assessed by using the Oxford Hip Score, UCLA activity score and Euroqol score. Radiographs were assessed for osteolysis and wear. BHR were also assessed for the presence of a pedestal sign around the femoral component.

Results: The mean follow up of the BHR group was 9 years (8.17 to 10.33) and for hybrids 10 (7.53 to 14.5). Four patients had died in the hybrid group and one in the BHR. Four were lost to follow up in each group. The revision rate in the BHR group was 9.25% verses 18% in the Hybrid, a further eight patients in the hybrid group have evidence of wear and osteolysis and are intended for revision (p=0.008). One patient in the BHR group was explored for late onset sciatic nerve palsy. All patients in the hybrid group had evidence of polyethylene wear, mean 1.24mm (0.06–3.03). 90% of the BHR group had evidence of a pedestal sign.

Satisfactory function was shown in both groups. There was no significant difference between groups with respect to the OHS but the UCLA score was superior in the BHR group (p=0.008). There was no significant difference for Euroqol visual analogue score. 56% of hybrids were delighted with their hip replacement verses 65% of BHR patients.

Discussion: After ten years the hip resurfacing patients were still more active and had a lower revision burden than the hybrid hip replacements. Both groups showed worrying radiological evidence of change with long-term follow-up.


GS Carlile CP Wakeling ED Fern

The Ganz trochanteric flip osteotomy has gained popularity in recent years as a surgical approach that can be used when performing debridement surgery and hip resurfacing. The advantages include preservation of blood supply to the femoral head, maintenance of abductor strength and exposure. Morbidity associated with the trochanteric osteotomy is however a problem.

We reviewed the complications associated with the trochanteric flip in 367 patients that had undergone hip resurfacing arthroplasty. Pain, either felt deep within the groin or from prominent screws heads laterally was a significant problem for 96 patients (26.1%) and necessitated screw removal under general anaesthesia at a mean time of 16 months postop. Of these, 14 patients (14.5%) continued to have pain, with 8 patients proceeding to revision surgery; 5 for refractory pain, 1 for aseptic loosening, 1 for aseptic lymphocyte dominated vasculitis associated lesion (ALVAL) and 1 for acetabular soft tissue impingement.

Trochanteric non-union, leading to further surgery, was diagnosed in 24 patients (6.5%) whom underwent reattachment at a mean time of 6 months postop. Within this group the majority of patients were male (16), with a mean age of 53.5 years (range 35 to 65). Trochanteric non-union was associated with smoking, diabetes, obesity, age and non-compliance. Following reattachment surgery, all patients went on to union.

In total 120 patients experienced complications associated with the trochanteric osteotomy that resulted in a need for further surgery, a re-operation rate of 32.6%. Pain from trochanteric screws appears to be the over whelming issue. Surgeons using the trochanteric flip should be aware of the morbidity associated with the approach and counsel patients accordingly pre-operatively. Patients presenting with ongoing pain following screw removal should be investigated extensively for serious underlying problems.


DJ Langton SS Jameson TJ Joyce AVF Nargol

Background: Blood metal ion levels have been shown to correlate with wear of retrieved components. Increased articular wear is associated with early failure. It is not clear what the management of patients with raised metal ions who remain asymptomatic should be.

Methods: A prospective study of the DePuy ASR resurfacing device was commenced in 2004 at our independent centre. Blood and serum metal ion analysis is carried out routinely. We assessed the clinical outcome of all patients with cobalt (Co) concentrations > 5μg/L (n=25). We consider this value to be a clear indicator of a poorly performing bearing surface. Patients who remained asymptomatic were brought back for repeat ions testing and clinical assessment. A parallel study was carried out to examine the relationship between the wear depth of retrieved explants (assessed using a coordinate measuring) and blood ion levels

Results: Increases in chromium(Cr) and Co levels from the second blood sample correlated with the first sample (p< 0.05). The four patients with the highest Cr Co levels went on to suffer spontaneous femoral neck fractures between 3 and 4 years post op (pseudotumours in two of these cases). Of the remaining 25, 5 were revised for worsening pain (large effusions and areas of tissue necrosis were seen at revision) and 10 were under investigation for new onset of pain. Wear depths correlated well with blood ion concentrations (p< 0.05) substantiating the results of another centre.

Conclusion: 60% of patients with raised metal ion levels went on to develop complications within two years of the blood test. This suggests patients may only have temporary tolerances to excessive concentrations of metal wear debris. One novel association appears to be spontaneous delayed femoral fracture. Results suggest increased ion concentrations associated with small joint size/sub optimal cup orientation will continue to rise and these patients should be followed up closely.


DJ Langton SS Jameson M Van Oursouw K De Smet AVF Nargol

Background: Definitive cup position for the reduction of blood metal ion levels has yet to be established.

Methods: Samples for serum metal ion analysis are taken routinely from patients under the care of the two senior authors of this paper. Both are high volume experienced hip resurfacing surgeons, one based in England, the other in Belgium. Metal ion results from two centres from patients with unilateral joints were correlated to size and orientation of femoral and acetabular components, UCLA activity score, age, time post surgery and post operative femoral head/neck ratios. EBRA software was used to assess cup inclination and anteversion on standing radiographs.

Cup orientation in vivo was compared to explant analysis of 60 retrieved resurfacing components using a coordinate measuring machine.

Results: Three resurfacing devices were studied. There were 620 results in total. Only femoral size and cup inclination/anteversion were found to have any effect on ion levels. In all devices, metal ion levels were inversely related to femoral size (p< 0.05). The device providing the smallest acetabular coverage arc was associated with the highest metal ion levels. Consistent throughout the implants, lowest ion levels were associated with cups with radiological inclination of 40–50° and anteversion 10–20°. Cup inclination angles lower than 40° were associated with posterior edge loading and likely sub-luxation of the femoral component.

Conclusion: The greater the coverage angle provided by the acetabular component, the greater the tolerance to suboptimal position. Lowest ion levels were found in well positioned lower clearance devices. Cup inclination/ante-version angles of 45/15+/−5° were associated with low ion levels in all three devices. We do not recommend cups to be placed with inclination angles below 40°.


V Bucknall CW McBryde M Revell PB Pynsent

Introduction: The Oxford hip score (OHS) instrument is used to assess pain and disability before and after hip arthroplasty and may be used as a standard for auditing pre and post-operative patients. It has been suggested that patients with a low pre-operative hip score (< 25th percentile) should be carefully assessed before surgical management is employed. This study aimed to determine the factors that influence a surgeon’s decision to undertake hip arthroplasty in patients with a low pre-operative hip score.

Methods: All patients who underwent hip arthroplasty over a two month period (n=121) were included. Of these, four pre-operative OHS questionnaires were missing. The remaining (117) were validated and those scoring below the published 25th percentile (58.3%) were selected (n=35), termed the ‘low-group’. Individual OHS responses scored 0–4 were examined (0 = no impairment and 4 = worst impairment) and the proportional differences between the responses for this group and the remaining 75% were investigated. The pre-operative radiographic Tönnis stage of osteoarthritis was determined.

Results: The median cohort OHS was 68.8% (IQR = 50–79%). Of the questions that scored highly, 59% were purely pain related, 14% function and 27% both. 66% of patients experienced moderate/severe pain and 31% suffered night pain. The ‘low-group’ never scored 4 (worst impairment) on questions concerning washing, transport, shopping, stairs and work. However, 57% scored 4 on questions encompassing a pain component. In all questions except donning socks and walking, the proportion of 4 in the ‘low-group’ was significantly different to the remainder of the cohort. Tönnis grade 3 (osteophytes and advanced loss of joint space) osteoarthritis predominated (49%).

Conclusion: Arthroplasty in patients with low pre-operative OHS is influenced mainly by pain affecting quality of life. Half of these patients also have advanced features of osteoarthritis on radiographic assessment despite the low scores.


PTH Lee O Safir DJ Backstein AE Gross

Introduction: The objective for this study was to assess the long term results for minor column allograft used in revision hip arthroplasty.

Methods: We prospectively included patients undergoing acetabular cup revision using minor column allograft with a minimum of 5 years follow-up. Minor column allograft was used in uncontained acetabular bone defects of sizes between 30% and 50% of the acetabulum. Acetabular failures requiring re-revisions at any time after surgery were included. Acetabular failure for any cause requiring re-revision surgery was used as end-point. Graft failure was considered when re-revision required the concurrent use of structural bone graft, metal augments or excision arthroplasty for any cause.

Results: There were 65 cases that met the study criteria. We included 5 deaths with a mean follow-up of 11.9 years (6.8–14.8) and 10 losses to follow-up after a mean follow-up of 11.7 years (5.3–17.4). Twenty eight acetabulum failed, with 14 occurring before 5 years at a mean of 1.8 years (0.1–4.8) and 14 occurring after 5 years at a mean of 12.2 years (5.6–23.2). Causes included aseptic loosening (23), infection (2), dislocation (1), graft non-union (1) and cup fracture (1). Fourteen grafts failed, with 8 occurring before 5 years at a mean of 1.2 years (0.5–4) and 6 occurring after 5 years at a mean of 11.3 years (6–23.2) after surgery. The mean improvement in modified Harris Hip Scores was 32.3 at 1 year and 32.6 at last follow-up assessment. The cup survivorship was 56.9 % and graft survivorship 78.5 % at a mean follow-up of 16.3 years (5.3–24.8).

Discussion: Metal augments have been used in revision arthroplasty for low demand patients but we recommend the use of minor column allografts in higher demand patients who are more likely to require further revision surgery.


TJ Joyce DJ Langton J Lord H Grigg SS Jameson N Cooke C Tulloch R Logishetty D Meek AVF Nargol

Background: There is a paucity of published data with regard to the wear of failed metal on metal (MoM) resurfacing devices.

Materials and Methods: MoM components retrieved from patients from two independent centres experiencing failure secondary to ARMD were analysed using a Mitutoyo Legex 322 coordinate measuring machine (CMM) which has an accuracy of 0.8 microns. Between 4000 – 6000 points were taken on each explant, dependent on the size of the bearing surface. Maximum wear depths and total volumetric wear were calculated. These values were compared to those from control samples retrieved following uncomplicated fractures/femoral collapse secondary to avascular necrosis (after calculating equivalent yearly wear rates).

Results: 58 ARMD components were analysed. This included 22 36mm MoM THRs (DePuy Pinnacle), 28 DePuy ASRs and 8 Zimmer Duroms. There were 30 resurfacing fracture/avascular necrosis controls. Volumetric wear rates and maximum wear depths of ARMD resurfacing components were significantly greater than the resurfacing control group for both the ASR and Duroms (p< 0.05) however 2 ARMD components exhibited similar amounts of wear compared to controls. Wear rates of the ARMD THR group were significantly lower than the ARMD resurfacing group (p< 0.05).

Conclusions: Increased articular wear is associated with an increased incidence of local adverse effects including tissue necrosis, joint effusions and fractures. However, there are a minority of patients who can develop tissue necrosis in the absence of accelerated wear, implying a spectrum of sensitivity This is reflected in the incidence of ARMD in the patient groups at the main study centre: > 5% in the ASR group and approx 1% in the THR group. We believe this indicates a failure of adequate lubrication and the resultant negative effects in larger bearing devices.


F Daley Morris X Griffin D Griffin

Introduction: Injuries to the ligamentum teres are being recognised more often with developments in imaging, such as MR arthrography, and the increasing use of hip arthroscopy. But they are difficult to diagnose, and it is not clear how best to treat them. Little is known about the mechanism of injury, nor the potential impact on hip stability of such injuries. The relationship between capsular and ligamentous contributions to stability has not been investigated.

Methods: We examined the movement of the ligamentum teres in intact, fully reduced, cadaveric hip specimens by trans osseus arthroscopy. The movement of the ligamentum teres was captured with video throughout the excursion of the hip joint. The influence of restraining capsular structures was determined by sequential transection and repeat excursion testing. Ligamentum teres injuries were generated by extreme movements, and compared with clinically observed injuries.

Results: The action of the ligamentum teres was successfully recorded in by video. The ligament was found to be the principal restraint to external rotation in extension and abduction. Injuries generated by forced rotation in this position resembled those seen in clinical practice.

Conclusion: Knowledge of the action of the ligamentum teres will improve our understanding of injury to this structure. It helps to identify described mechanisms which should raise suspicion of such an injury, and may help to design investigation and treatment protocols.


S Karthikeyan D Griffin

Introduction: Chondral lesions are the second most common pathology encountered during hip arthroscopy. Microfracture is a simple and effective technique to treat chondral lesions with proven long term results in the knee. However, there is little evidence to confirm the ability of microfracture to produce repair tissue in hip joint.

Methods: Patients with acetabular chondral defect treated with microfracture during primary arthroscopy and who had a subsequent hip arthroscopy enabling visualisation of the treated chondral defect were included in the study. Over a three year period 185 patients had microfracture for treatment of full thickness chondral defect. 11 patients (8 males and 3 females) with a mean age of 35 years (range 17–54 years) who had revision hip arthroscopy form the study population. The size of chondral defect was measured at the time of primary arthroscopy. Microfracture was performed using arthroscopic awls with a standard technique. Postoperatively a strict rehabilitation protocol was followed. The extent and quality of repair tissue was assessed by visual inspection at second look arthroscopy

Results: All patients had chondral lesions confined to the antero-superior aspect of the acetabulum with an associated labral tear. None had diffuse osteoarthritis. The average defect measured 180 mm2 (range 50–300). The mean time interval between primary and revision arthroscopy was 12 months. Excluding one failure the overall percent fill of the defects was 95% (range 75 – 100) with good quality cartilage.

Discussion: Only one other series has reported on the macroscopic results of microfracture in the hip. Our series agrees with the results of those authors. These similar results from 2 centres confirm that arthroscopic microfracture is an effective treatment for acetabular chondral lesions in carefully selected patients.


S Glyn-Jones A Roques C Esposito W Walter M Tuke D Murray

Introduction: Metal on metal hip resurfacing arthroplasty-induced pseudotumours are a serious complication, which occur in 1.8% of patients who undergo this procedure in our institution. The aim of this study was to measure the 3D in vivo wear on the surface of resurfacing components revised for pseudotumour, compared to a control group.

Method: Thirty-six hip resurfacing implants were divided into two groups; 18 patients with a clinical and histopathological diagnosis of pseudotumour and 18 controls (revised for femoral neck fracture and infection). Three dimensional contactless metrology (Redlux Ltd) was used to scan the surface of the femoral and acetabular components, to a resolution of 20 nanometers. The location, depth and area of the wear scar were determined for each component. A separate blinded analysis to determine the presence of absence of impingement was performed by one of the authors.

Results: The volumetric wear rate for femoral component of the pseudotumour group was 3.29 mm3/yr (SD5.7) and 0.79 mm3/yr (SD1.2) for the control group (p=0.005). In the pseudotumour group, the volumetric wear rate of the acetabular component was 2.5 mm3/yr (SD6.9) compared to 0.36 mm3/yr (SD0.80) for the control group (p=0.008). Edge-wear was detected in 89% of acetabular components in the pseudotumour group and 21% of those in the control group (p=0.01). Anterior or posterior edge-wear, consistent with impingement was present on the femoral components of 73% of patients in the pseudotumour group and 22% in the control group (p=0.01).

Discussion: This work demonstrates that implants revised for pseudotumour have significantly higher volumetric wear rates than controls. They also have a significantly higher incidence of edge-wear than controls. We suggest that a significant proportion of pseudotumours are associated with high concentrations of metal wear debris; however a minority may result from a hypersensitivity reaction to metal ions.


Ru Li Kivanc Atesok David Wright Aaron Nauth Cari M Whyne Emil H Schemitsch

Purpose: Severe fractures damage blood vessels and disrupt circulation at the fracture site resulting in an increased risk of poor fracture healing. Endothelial progenitor cells (EPCs) are bone-marrow derived cells with the ability to differentiate into endothelial cells and contribute to neovascularization and re-endothelialization after tissue injury and ischemia. We have previously reported that EPC therapy resulted in improved radiographic healing and histological blood vessel formation in a rat fracture model. The purpose of this study was to further quantify the effects of EPC therapy with microCT and biomechanical analyses.

Method: Five-millimeter segmental defects were created and stabilized in the femora of 14 fisher 344 rats. The treatment group (n=7) received 1x106 EPCs within gelfoam locally at the area of the bone defect and control animals (n=7) received only saline-gelfoam with no cells. The formation and healing of bone after 10 weeks were asessed by radiographic, micro-CT and biomechanical analyses.

Results: Radiographically all the animals in EPC-treated group healed with bridging callus formation, whereas control group animals demonstrated radiographic non-union. Micro-CT assessment demonstrated significantly improved parameters of bone volume (35.34 to 20.68 mm3, p=0.000), bone volume density (0.24 to 0.13%, p=0.001), connectivity density (25.13 to 6.15%, p=0.030), trabecular number (1.14 to 0.51 1/mm, p=0.000), trabecular thickness (0.21 to 0.26 mm, p=0.011), trabecular spacing (0.71 to 1.88 mm, p=0.002), bone surface area (335.85 to 159.43mm, p=0.000), and bone surface to bone volume ratio (9.43 to 7.82 1/mm, p=0.013) in the defect site for the EPC group versus the control group respectively. Biomechanical testing showed that the EPC treatment group had a significantly higher torsional strength compared with the control group (EPC=164.6±27.9 Nmm, Control=29.5±3.8 Nmm; p value = 0.000). Similarly, the EPC treated fractures demonstrated significantly higher torsional stiffness versus controls (EPC=30.3±5.0 Nmm/ deg, Control=0.9±0.1 Nmm/deg; p value = 0.000). When biomechanically compared to contralateral intact limbs, the EPC treated limbs had similar torsional stiffness (p=0.996), but significantly lower torsional strength (p=0.000) and smaller angle of twist (p=0.002).

Conclusion: These results suggest that local EPC therapy significantly enhances fracture healing in an animal model. The biomechanical results show that control animals develop a mechanically unstable non-union. In contrast, EPC therapy results in fracture healing that restores the biomechanical properties of the fractured bone closer to that of intact bone.


Louis M Ferreira Timothy H Bell James Andrew Johnson Graham J King

Purpose: Most displaced olecranon fractures can be treated with ORIF. However with severe comminution or bone loss, excision of the fragments and repair of the triceps to the ulna is recommended. The triceps can be reattached to either the anterior or posterior aspect of the ulna. The purpose of this in-vitro study was to determine the effect of triceps repair technique on elbow laxity and extension strength in the setting of olecranon deficiency.

Method: Eight unpreserved cadaveric arms were used (age 75 ± 11 years). Surface models were generated from CT images and sequential olecranon resections in 25% increments were performed using real-time navigation. Muscle tendons (biceps, brachialis, brachioradialis and triceps) were sutured to actuators of an elbow motion simulator, which produced active extension. A tracking system recorded kinematics in the varus and valgus positions. A triceps advancement was performed using either an anterior or posterior repair to the remaining olecranon in random order. Triceps extension strength was measured in the dependent position with the elbow flexed 90° using a force transducer located at the distal ulnar styloid, while triceps tension was increased from 25–200 N. Outcome variables included maximum varus-valgus elbow laxity and triceps extension strength. Two-way repeated measures ANOVAs were performed for laxity comparing resection level and repair method. Three-way repeated measures ANOVAs were performed for triceps extension strength comparing triceps tension, resection level and repair method. Significance was set at p < 0.05.

Results: Progressive olecranon resection increased elbow laxity (p < 0.001). Although the posterior repair produced slightly greater laxity for all but the 50% resection, this difference was not significant (p = 0.2). The posterior repair provided greater extension strength than the anterior repair at all applied triceps tensions and for all olecranon resections (p = 0.01). The initial 0% resection reduced extension strength for both repairs (p < 0.01), however, there was no effect of progressive olecranon resections (p = 0.09).

Conclusion: There was no significant difference in laxity between the anterior and posterior repairs. Thus even for large olecranon resections, the technique of triceps repair does not have significant influence on joint stability. Extension strength was not reduced by progressive olecranon resections, perhaps due to wrapping of the triceps tendon around the trochlea putting it in-line with the ulna and giving it a constant moment arm. Triceps extension strength was higher for the posterior repair. This is likely due to the greater distance and hence moment arm of the posterior repair to the joint rotation center. Conversely, the anterior repair brings the triceps insertion closer to the joint center, reducing the moment arm. Since there was no significant difference in laxity between the repairs, the authors favour the posterior repair due to its significantly higher triceps extension strength.


Kevin A Hildebrand Mei Zhang Paul T Salo David A Hart

Purpose: The objective of the present study was to determine whether human mast cells can modify behavior of human elbow contracture capsule cells in an in vitro collagen gel contraction assay.

Method: Posterior elbow joint capsule was obtained from a 38 year old man with a chronic (> 1 year) post-traumatic joint contracture. Joint capsule cells were isolated and suspended at a density of 2.5 x 105 cells/ml, and mixed with neutralized Collagen solution composed with 58% Vitrogen 100 purified collagen. Aliquots of collagen gel without cells, with only the human mast cell line, HMC-1 (2.5× 105), human capsule cells (2.5 × 105), human capsule cells (2.5 × 105) and an equal number of mast cells (1:1), or human capsule cells (2.5× 105) and 7.5× 105 mast cells (1:3) were then cast into wells tissue culture plate. The gels were maintained with 0.5 ml DMEM composed with 2% BSA and incubated at 37°C for 12 h for gelation to occur. After 12 hr initial culture, the gels were detached from the wall and the bottom of culture plate wells, and gel area was determined at 0h, 2h, 4h, 6h, 24h, 48h, and 72h Gel contraction studies were carried out on passage 6 and done in triplicate. The blocking assay to inhibit mast cell – joint capsule cell interaction employed antibodies to Stem Cell Factor (SCF) and c-kit. SCF (0.5, 1 or 10 microg/ml) and/or c-kit (0.05, 0.1 or1 microg/ml) were added individually or in combination (SCF 10 microg/ ml and c-kit 1 microg/ml only) to cells/collagen gel mixture before gel casting. The ratio of human capsule cells and HMC-1 were kept constant at 1:3 throughout the experiment. The inhibitory effect of SCF and c-kit antibodies on collagen gel contraction induced by human capsule cells and HMC-1 was expressed in percentage of gel areas at 24h post release. Inhibition effect (%) = 100% – [(gel size – c-kit or SCF gel size)/(blank gel size – JC:M gel size)x 100%]. Statistical analysis involved an ANOVA with posthoc Bonferroni correction. P < 0.001 was significant. Data are mean ± standard deviation.

Results: Joint capsule cells were able to contract collagen gels in a time-dependent manner. This contraction was significantly enhanced in the presence of the HMC-1 cells in a dose dependent fashion (p < 0.001). HMC-1 cells were unable to contract the collagen gels by themselves. Experiments with antibodies to the mast cell – fibroblast direct cell-cell communication determinants SCF or c-kit showed inhibition of the enhanced contraction at 24 hours between 43 – 72%. Combining the highest dose of SCF and c-kit led to 82% inhibition.

Conclusion: This study has shown that cells isolated from human elbow joint contracture capsules respond to mast cells in a collagen gel assay in a dose dependent manner. This study is consistent with our previous work which has shown that ketotifen, a mast cell stabilizer that prevents mast cell degranulation and liberation of factors, can reduce contracture severity in a rabbit model of post-traumatic joint contractures.


Aaron Nauth Emil H Schemitsch Ru Li

Purpose: The purpose of this study was to compare the effects of two types of stem/progenitor cells on the healing of critical sized bone defects in a rat model. Endothelial Progenitor Cells (EPCs), a novel cell type with previously demonstrated effects on angiogenesis in animal models of vascular disease, were compared to both a control group of no cell therapy, and a treatment group of Mesenchymal Stem Cells (MSCs). The hypothesis was that EPCs would demonstrate both superior bone healing and angiogenesis, when compared to the control group and MSC group.

Method: EPCs and MSCs were isolated from the bone marrow of syngeneic rats by differential culture and grown ex vivo for 10 days. Subsequently the cells were harvested, seeded on a gelfoam scaffold, and implanted into a 5mm segmental defect in a rat femur that had been stabilized with a plate and screws. Bone healing was assessed radiographically and by microCT. Angiogenesis was assessed by histology and physiologically, using laser doppler to assess blood flow in the bone and soft tissues. All animal protocols were approved by and performed in accordance with the St. Michael’s Hospital Animal Care Committee. ANOVA was used to test for significant differences between the groups, and a p-value of < 0.05 was considered statistically significant.

Results: The EPC (n=14) group demonstrated radiographic evidence of healing of the bone defect as early as 2 weeks, and all specimens were radiographically healed at 6 weeks. Both the control group (n=14) and the MSC group (n=14) showed no radiographic evidence of healing at 10 weeks. MicroCT comparison of the EPC group versus the control group showed significantly greater bone volume and density at the defect site (p< 0.001). More blood vessel formation was observed in the EPC group versus the control group on histology at 2 weeks. Laser Doppler assessment showed significantly more soft tissue and bone blood flow at 2 and 3 weeks in the EPC group versus the control group (p=0.021).

Conclusion: The results of this study demonstrate that EPCs are effective as cell-based therapy for healing critical sized bone defects in a rat model. In this model EPCs demonstrated superiority to MSCs with regard to bone healing. In addition, EPCs demonstrated superior angiogenesis over controls in a rat model of fracture healing. These results strongly suggest that EPCs are effective for therapeutic angiogenesis and osteogenesis in fracture healing. There is a clinical need for effective strategies in the management of traumatic bone defects and nonunions. Investigation into the use of MSCs as an effective alternative to autologous bone grafting has failed to translate into clinical use. It is possible that EPCs are more effective at the regeneration of bone in segmental defects because of their synergistic effect on angiogenesis and osteogenesis. Further research into EPC based therapies for fracture healing is warranted.


Louis M Ferreira Katherine E Fay Emily A Lalone James A Johnson Graham J King

Purpose: Techniques to quantify soft-tissue forces in the upper extremity are not well described. Consequently, ligament forces of the elbow joint have not been reported. Knowledge of the magnitudes of tension of the primary valgus stabilizer, the anterior bundle of the medial collateral ligament (AMCL), would allow for an improved understanding of the load bourne by the ligament. The purpose of this in vitro study was to quantify the magnitude of tension in the native AMCL throughout flexion with the arm in the valgus orientation. We hypothesized that tension in the AMCL would increase with flexion.

Method: Five fresh-frozen cadaveric upper extremities (mean age 72 ± 10 years) were tested. To produce active muscle loading in a motion simulator, cables were affixed to the distal tendons of the brachialis, biceps brachii, triceps brachii, and brachioradialis and attached to actuators. The wrist was fixed in neutral flexion/extension and the forearm in neutral rotation. The arm was orientated in the valgus gravity-loaded position. A custom designed ligament load transducer was inserted into the AMCL. Active simulated flexion was achieved via computer-controlled actuation while passive elbow flexion was achieved by an investigator manually guiding the arm through flexion. Motion of the ulna relative to the humerus was measured using a tracking device.

Results: Both the active and passive motion pathways showed an increase in AMCL tension with increasing angles of elbow flexion (p < 0.05). There was no difference in AMCL tension levels between active and passive elbow flexion (p = 0.20). The mean maximum tension achieved was 97±33N and 94±40 N for active and passive testing respectively.

Conclusion: AMCL tension levels were observed to increase with elbow flexion, indicating that other structures (such as the joint capsule and the shape of the articulation) are likely more responsible for joint stability near full extension, and that the AMCL is recruited at increased angles of elbow flexion. With respect to load magnitudes, Regan et al. found the maximum load to failure of the AMCL was 261 N, while Armstrong et al. reported a failure load of 143 N in cyclic testing. The maximum AMCL tension level observed in this study was 160 N. Failure of the AMCL was not observed, which may be due to differences in specimen size, age, or the method of load application. In summary, this in vitro cadaveric study has provided a new understanding of the magnitudes of AMCL tension through the arc of elbow flexion, and this has important implications with respect to the desired target strength of repair and reconstruction techniques. These findings will also assist in the development and validation of computational models of the elbow.


Chao Chen Lianteng Zhi Xiaoli Pang Hasan Uludag Hongxing Jiang

Purpose: The current clinical treatment protocol for bone healing applies super-physiological dose of rhBMP7. Unfortunately, it may result in adverse side effects. Some studies have demonstrated a dose-dependent osteogenic differentiation using rodent bone marrow derived stem cells (BMSCs). However, the dose effect of BMP7 on osteogenic differentiation of normal human BMSCs is largely unknown. In the present study, we investigated in vitro osteogenic differentiation of hBMSCs with a gradient concentration of rhBMP7. The interaction between rhBMP7 and osteogenic differentiation medium (ODM) was also examined.

Method: The primary BMSCs from human bone marrow were cultured and maintained in MSC growth medium (MGM). Six study groups were designed: MGM only, MGM with rhBMP7 of 0.1ug/ml, ODM only, and ODM with 3 concentration of rhBMP7 of 0.01μg/ml, 0.1μg/ml, and 1.0μg/ml, respectively. Alkaline phosphatase level (ALP) at day 17 and cumulative calcium deposit at both day 17 and day 35 were examined. mRNA expression level of osteogenic markers including osteocalcin (OC), osteopontin (OPN) and ALP were quantified using real-time RT-PCR at day 17.

Results: ALP activity at day17 did not increase in MGM with or without 0.1μg/ml of rhBMP7, ODM alone and ODM with 0.01μg/ml of rhBMP7. ALP activity was much higher with 0.1μg/ml of rhBMP7 plus ODM (0.22±0.02IU) than that in MGM with 0.1μg/ml of rhBMP7 (0.01±0.01IU, P< 0.05).

Conclusion: Our study demonstrated that rhBMP7 induced osteogenic differentiation of hBMSCs in a dose-dependent manner in the presence of ODM and the minimal dose for inducing in vitro osteoblastic differentiation was 0.1ug/ml of rhBMP7 under synergistic effect of ODM. The results of this study provide some insights into further investigation of synergy of rhBMP7 with other molecules. The types and amounts of simple molecules could significantly reduce therapeutic dose of rhBMP7 and achieve equivalent or better outcomes in clinical application warrant further investigation.


Christopher R Geddes Ulrich Studler Melanie Deslandes Lawrence White Marshall Sussman John Theodoropoulos

Purpose: In evaluating injury severity of acute medial collateral ligament (MCL) injuries, the current standard is to perform a history and physical examination and static MRI of the injured joint. With recent advances in dynamic MR imaging technology, we hypothesized that concurrent physical examination and dynamic MRI of the knee joint in patients with acute MCL injuries is feasible and would provide new insight into the injured joint kinematics while correlating to clinical and diagnostic imaging criteria for injury severity.

Method: 10 patients (5 male, 5 female) with isolated, unilateral, acute MCL injuries were prospectively enrolled in the study. An orthopedic surgeon performed initial physical examination and clinical grading. Dynamic MRI with concurrent physical examination was performed in a 1.5T wide-bore magnet and compared to the uninjured knee as a control. The dynamic MR imaging data was compared with morphologic MCL changes on static MRI, with dynamic examination of the contralateral knee and with the clinical grading of MCL injury. The width of the medial joint space and the opening angle between the femur and tibia were measured.

Results: Clinically, one patient had grade 1 and nine had grade 2 injuries. Using morphologic MRI criteria there were nine grade 2 and one grade 3 injuries. Mean and median medial opening angles of all affected knees was 2.8/2.5 mm and 2.8/2.6°, respectively, as compared to 1.8/1.8 mm and 2.2/2.1° in the normal side. Measurements of medial joint-space opening showed little quantitative difference between grade 1, 2 and 3 injuries. Interobserver agreement (intraclass correlation coefficients) varied from 0.9 to 0.93.

Conclusion: Dynamic MR imaging with concurrent physical examination is feasible and correlates to clinical and morphologic grading of severity. Our study suggests that traditional clinical grading systems of MCL injuries overestimate medial joint space opening.


Chao Chen Hasan Uludag Alex Rezansoff Hongxing Jiang

Purpose: The osteogenic effects of BMPs on mesenchymal stem cells (MSCs) are less profound in human as compared to rodent. The mechanism for this phenomenon is unclear. This study evaluated the effects of macrophages on proliferation and BMP-2 induced osteogenic differentiation of human MSCs.

Method: MSCs were isolated from human bone marrow. Human monocytes THP-1 (human acute monocytic leukemia cell line) were induced into macrophages by phorbol myristate acetate. The conditioned media (CM) from monocytes and macrophages were collected separately. After treated with CM from monocytes or macrophages for 5 and 7 days, the proliferation rate of human MSCs was determined by WST-8 assay. A group without CM served as control. Pretreated human MSCs were then induced towards osteogenic differentiation by osteoinductive medium supplemented with 0.1ug/ml BMP-2. Expression levels of osteogenic markers were determined by real-time quantitative PCR. Alkaline phosphatase (ALP) activity and mineral deposition were assessed by p-NPP colorimetric kinetic assay and calcium assay, respectively.

Results: The number of MSCs was significantly decreased in the group with macrophage CM at both 5 and 7 days (both p< 0.001) as compared with control group, but not in the group with monocytes CM. Expression levels of ALP and bone sialoprotein 2 in the macrophage CM group were significantly lower than those in the control group (p=0.003 and p< 0.001, respectively). ALP activity was also significantly lower in the group with macrophage CM than control group (p< 0.001). Although the expression levels of osteocalcin and RUNX2 as well as calcium deposition in the macrophage CM group were reduced, they did not reach statistical significance.

Conclusion: Macrophages suppressed the proliferation of MSCs and inhibited BMP-2 induced osteogenic differentiation of human MSCs. In addition to known BMP antagonists, macrophages might be another important factor in suppressing the osteogenic effect of BMP-2 on human MSCs.


Chan Gao Oliver Nguyen Vahid Serpooshan Bilal Eichaarani Showan N Nazhat Edward J Harvey Janet E Henderson

Purpose: Poor bone quality is a common challenge to orthopaedic surgeons and frequently leads to complications such as non union and implant failure, particularly the elderly whose capacity for tissue repair is significantly reduced. The current study was designed to determine if bone marrow derived mesenchymal stem cells (MSC) seeded in dense collagen scaffolds and delivered to a surgically-induced femoral defect will expedite bone healing.

Method: Ex Vivo: MSC isolated from four month old donor mice were expanded ex vivo, seeded into hydrated type I collagen, which was subjected to unconfined compression to generate dense collagen scaffolds. The cell-seeded scaffolds were then cultured for up to 21 days. MSC viability was monitored using the AlamarBlue® metabolic assay and differentiation into osteoblasts using alkaline phosphatase (ALP) and von Kossa stain. In Vivo: A 3mm x 1mm window defect was drilled in the femur of elderly recipient C57Bl6 and C3H mice. The C3H mice were assigned to one of two study groups:

LEFT femur drill hole alone; RIGHT femur acellular scaffold.

LEFT femur acellular scaffold; RIGHT femur cell-seeded scaffold.

The quantity and quality of bone regeneration was assessed after 2 and 4 weeks using micro computed tomography (mCT) and histology.

Results: Ex Vivo: The dense collagen scaffold had superior mechanical properties and supported the survival and differentiation of MSC into osteoblasts up to 21 days in culture. Cells in uncompressed gels and those in compressed gels in non-osteogenic medium, had fewer ALP-positive cells at early time point and less mineral deposited at later times compared with those in compressed gels in osteogenic medium. In Vivo: A high incidence of postoperative fracture was seen in C57Bl6 mice compared with age matched C3H mice in the first study group. Furthermore, the empty surgical defect healed more rapidly than that containing the dense collagen scaffold, in which bone volume compared with tissue volume (BV/TV), trabecular number (Tb.N.) and connectivity were lower. In study group two, bone regeneration was evident at 2 weeks post operative and transplantation of MSC-seeded dense collagen scaffolds resulted in higher BV/TV, Tb.N. and trabecular connectivity compared with the acellular dense collagen scaffold.

Conclusion: Bone fragility in elderly C57Bl6 mice led to post operative fracture after generation of a non-critical sized drill hole defect in the proximal femur whereas age-matched C3H mice with higher bone mass sustained no fractures. Dense collagen scaffolds supported the survival and osteoblast differentiation of bone marrow derived MSC in 3D culture. Their superior mechanical properties allowed for transplantation into non-critical sized femoral defects, suggesting the approach shows promise as adjunct therapy for use with bone grafts and implants in patients with poor quality bone.


Thomas R Turgeon Eric Bohm Nathan Kesler Martin Petrak Colin Burnell David Hedden

Purpose: The purpose of this study is to determine if the addition of Tobramycin antibiotic powder to cement for primary hip replacement surgery increases the risk of long term aseptic loosening. This was accomplished by measurement of implant micromotion with Radiostereometric Analysis (RSA).

Method: Exeter femoral stems and Trident acetabular components were implanted into 33 patients. Stems were cemented in a randomized manner with either Simplex P or Simplex T. Tantalum beads were injected into the femur to serve as reference points for RSA measurements. RSA examinations were taken with supine positioning at six weeks, six months, one year, and two years post-operatively. Radiographic measurements and analyses were performed with the UmRSA software suite version 6.0 (RSA Biomedical, Umea, Sweden). Distal migration of the stem centroid was measured at each follow-up period and the mean migration rates for both groups were determined. Non-inferiority testing of stem migration in Simplex T compared to Simplex P was accomplished using a one sided t-test, with the significance level set at 0.05. A clinically inferior additional amount of distal migration was set at 0.4mm/yr.

Results: Eleven patients were excluded from the study: seven patients either dropped out of the study or missed the six week and/or two year follow-up examinations, two patients had radiographic image quality issues, and two patients had loosening of their tantalum markers in subsequent follow-ups. Of the remaining 22 patients, eight were male and 14 were female, with an average age at time of surgery of 71.2 (range, 63–81) years. The mean total distal migrations for the Tobramycin and non-Tobramycin cement groups at two years were 0.891 and 0.732 mm, respectively; the mean stem migration rates were 0.263 and 0.179 mm/yr, respectively. The differences in total distal migration and stem migration rate were not statistically significant (P = 0.06 and UCL = 0.173, respectively).

Conclusion: The addition of Tobramycin to Simplex cement does not appear to impact the distal migration pattern for a polished tapered cemented hip stem at two years. This finding suggests that Tobramycin does not have any clinically relevant deleterious effects on the in vivo mechanical properties of Simplex cement.


Kayode Olajide Oduwole Aaron A Glynn Funso O Onayemi Diamuird Molony Jim P O Gara Damien McCormack

Purpose: Biomaterial-related infections continue to hamper the success of reconstructive and arthroplasty procedures in orthopaedic surgery. Staphylococci are the most common etiologic agents, with biofilm formation representing a major virulence factor. Environmental stress factors and sub-inhibitory concentration of some antibiotics have been identified to trigger staphylococcal biofilm formation through increased icaADBC expression. In staphylococci, production of polysaccharide intercellular adhesin (PIA) by the enzyme products of the icaADBC operon is the best understood mechanism of biofilm development, making the ica genes a potential target for biofilm inhibitors. Aims of the current study were

Determine the minimum inhibitory concentration (MIC) of Povidone-iodine.

Investigate the effect of Povidone-iodine on icaADBC operon encoded staphylococcal biofilm formation.

Investigate wether any observed changes on biofilm by Povidone-iodine is mediated through a change in icaADBC operon.

Method: MIC of povidone – iodine for both reference strains and strains isolated from infected orthopaedic implants was determined. Biofilm assay was performed at different Povidone-iodine concentrations using 96-well polystyrene plates. Total RNA for cDNA synthesis was isolated from bacteria at different twofold dilutions of Povidone-iodine concentrations. Real time polymerase chain reaction was used to quantify effects of Povidone-iodine on gene expression pattern of the icaADBC operon using the constitutively expressed gyrB gene as internal control

Results: The MIC of povidone-iodine was 1.4% for all bacterial strains. Clinical in-use doses of povidone-iodine prevented biofilm formation.

A step-wise reduction of biofilm was observed at increasing sub-inhibitory doses of povidone-iodine (p< 0.0001).

IcaA expression correlated with biofilm formation in staphylococcal organisms. Decrease in icaA expression was strongly associated with an increase in expression in the biofilm repressor gene, icaR.

The repressive effect of povidone-iodine on biofilm formation by Staphylococcal bacteria is by a separate mechanism from its bacteriostatic mechanism of action.

Conclusion: This study shows that icaR is a potential therapeutic target through which the ability of Staphylococcal bacterial to form biofilm may be reduced. These data reveal an additional therapeutic benefit of povidone-iodine and suggest that studies to evaluate the suitability of povidone-iodine as biomaterial coating agent to reduce device-related infection rates are merited.


Ili Slobodian Eric Bohm Jo-Anne V Sawatzky Carolyn De Coster Martin J Petrak

Purpose: Deciding how to allocate scarce surgical resources is a worldwide issue. These decisions can be especially difficult when considering procedures aimed primarily at improving functional quality of life, such as lower extremity joint replacement (LEJR) surgery, and those procedures that can be perceived primarily as life preserving but should also have an impact on physical function, such as coronary artery bypass graft (CABG) surgery. A comparison of the functional outcomes of these two different procedures may provide further evidence to guide resource allocation decisions. The purpose of this study is to compare patient-reported functional outcomes following CABG and LEJR surgery using standardized, validated outcome metrics.

Method: A retrospective review of prospectively collected pre and post-operative health related quality of life (SF-36) measures from patients undergoing elective CABG and elective LEJR surgery in an academic surgical center. The sample included 112 CABG patients who were matched with LEJR patients based on gender and age.

Results: The mean age in the CABG group was 63 years, in the LEJR group 64 years. Seventy eight percent (78%) of the patients were male. Pre-operatively, CABG patients reported statistically higher (p< 0.05) Physical Functioning, less Bodily Pain, and superior Physical Component summary SF-36 scores compared to the LEJR group. However, their pre-operative General Health scores were statistically lower. Surgery resulted in a general improvement in all SF-36 scales and summary scores for all patients, with statistically significant improvements in Bodily Pain and General Health Scores occurring in both groups. Interestingly, the improvement in Bodily Pain score was greater for the LEJR group than the CABG group, whereas the improvement in General Health Score was greater in the CABG group. However the pre-operative pattern of statistically better Physical Functioning, Bodily Pain and Physical Component summary SF-36 scores in the CABG group, and superior General Health scores in the LEJR group remained following surgery.

Conclusion: It appears that, despite being matched for age and gender, significant pre-operative general health differences exist between CABG and LEJR patients that persist post-operatively. While surgery does result in significant improvements for both groups, CABG patients enjoy greater improvement in General Health scores while LEJR patients benefit from greater improvements in Bodily Pain scores. Further research is currently underway to examine how these differences are reflected in disease-specific scores and in health care resource utilization.


Kwan-Ching Geoffrey Ng Gholamreza Rouhi Mario Lamontagne Paul E Beaulé

Purpose: Femoroacetabular impingement (FAI) is recognized as a pathomechanical process that leads to hip osteoarthritis (OA). Past research has been focused on treatments for FAI; however, few studies have been done to link FAI with the progression of OA. It is hypothesized that elevated mechanical stimuli could provoke bone remodeling in the subchondral bone and articulating surfaces due to cam FAI (aspherical head-neck deformity), which would accelerate the progression of OA. Using finite element analysis (FEA), the aim is to compare healthy hips to hips with cam FAI – investigating the mechanical stimuli effect of FAI towards OA.

Method: Net joint reaction forces were obtained from joint kinematics, kinetics, and by inverse dynamics calculation for a dynamic squat motion of a control subject and a cam FAI patient (both males with comparable age, BMI, and femur lengths). CT scans were acquired from both subjects. Data slices were compiled using 3D-DOCTOR (Able Software Corp, MA) to form a 3D model with slice thickness calibrated at 1.25mm in the superior-inferior axis. ANSYS (ANSYS, PA) software was used for FEA. The femur models were given quadrilateral shell elements and modeled as linear elastic orthotropic materials. The ground reaction forces were applied to the femur models, simulating dynamic loads, using boundary conditions specific to hip loading. Von Mises stresses were determined to examine stress concentrations and adverse loading conditions. Strain energy distributions were determined to examine the effect of stimuli on the initiation and rate of bone remodeling.

Results: At the maximum squat-depth, the FEA results demonstrated that the net forces acting on the FAI hip produced high mechanical stimuli regions around the head and neck. The highest stress concentration (590 MPa) was located at the anterosuperior head-neck junction, where cam FAI is most prominent. For the control hip, stresses were significantly lower (maximum of 151 MPa) and dissipated around the head. For both the FAI and the control hip, the maximum strain energy concentrations were seen at the superior portion of the head (4.725 kJ vs. 2.192 kJ for FAI vs. control hip respectively).

Conclusion: The increase in mechanical stimuli can be due to the loading configurations as well as to the abnormal geometry of the cam deformity. Assuming that the strain energy density (SED) and its rate is linearly proportional to the rate of bone turnover, based on a recent semi-mechanistic bone remodeling theory, a higher rate of bone turnover is expected in the FAI than in a normal hip. Depending on the level and rate of SED, the rate of bone remodeling will vary in order to provide a new homeostatic configuration. The next-step analysis, examining the mechanical stimuli in the acetabulum and its cartilage, is currently in progress. This would provide useful information about the possible locations of OA initiation and establish a link between FAI with cartilage degeneration.


Joshua W Giles Andrew Glennie Louis M Ferreira George Athwal Kenneth J Faber James A Johnson

Purpose: Loosening of glenoid components in total shoulder arthroplasty is a common clinical problem which can necessitate revision surgery. The mechanism of loosening is poorly understood and may relate to implant design, component fixation techniques, and interfacial tensile stresses. We are unaware of any studies that have examined the fundamental aspects of load transfer to bone for various joint loading configurations. Hence, the objective of this study was to investigate the effect of joint loading on bone strain adjacent to a poly-ethylene glenoid implant.

Method: Five specimens (4 males; avg age: 59.5 yrs) implanted with a cemented, all polyethylene component (Anatomical Shoulder; Zimmer) were tested using an apparatus capable of producing loading vectors with various angles, magnitudes and directions. Each specimen was tested using a ramp load of 0–150 N (at 10N/sec) in two directions (superior and inferior) and with six angles of load application. A uniaxial strain gauge was placed in each of the four quadrants of the glenoid, approximately 1 mm medial to the glenoid rim. The primary axis of each strain gauge was oriented medio-laterally to record bone strains. The humeral head was simulated by a custom steel ball with a radius of curvature consistent with a nonconforming humeral prosthesis.

Results: The relationship between strain and applied force was not linear (superior quadrant at 40o: linear fit R2=0.96; quadratic fit R2=0.999; p< 0.0005), and was dependent on the loading angle. During pure compressive loading, tension was observed in the superior and inferior quadrants of the glenoid; while less consistent results in the anterior and posterior quadrants revealed variable tension and compression. Superior and inferior loading each caused increasing ipsilateral tension, occurring from 0–30o and 0–20o, respectively.

Conclusion: The current study is thought to be the first to directly measure load transfer at the implant-bone interface. We demonstrated load transfer nonlinearities between a surgically implanted glenoid component and the underlying bone in all locations and for a wide range of loading conditions. This has important implications towards the modeling of these constructs using finite element analyses. The results also illustrate tensile loading during compressive and small eccentricity loading cases. These results suggest a polyethylene flexure, causing the periphery of the glenoid implant to flex upwards placing the cement mantle and underlying bone in tension. Tensile loads that are linked to cement mantle fracture and implant loosening are produced under loading conditions associated with activities of daily living. This study has provided insight into the mechanisms of load transfer between a cemented polyethylene glenoid implant and the underlying bone. Reduction or elimination of these interfacial tensile stresses around the glenoid periphery should be considered when developing novel methods for component fixation.


Thomas R Turgeon Eric Bohm Nathan Kesler Martin Petrak Colin Burnell David Hedden

Purpose: The purpose of this study is to measure in vivo linear head penetration of a newer generation highly crosslinked liner (X3, Stryker Orthopedics) using Radiostereometric Analysis (RSA).

Method: The 12 hips (11 patients) included in this study are a subset from a larger randomized controlled trial comparing Exeter stem migration in cement mantles with and without Tobramycin. Criteria for inclusion in this subset were the use of an uncemented Trident acetabular component containing X3 polyethylene in combination with a 32 mm stainless steel femoral head. The average age was 72.7 years (range 65 to 80), and there was an equal gender distribution. RSA examinations were taken with patients lying supine at six weeks, six months, one year, and two years postoperatively. The six week examinations were used as the reference examinations for measuring head penetration. Radiographic measurements and analyses were performed with the UmRSA software suite version 6.0 (RSA Biomedical, Umea, Sweden). Head penetration was determined via edge-detection measurements of the femoral head and acetabular cup.

Results: The mean cumulative femoral head penetration at 6 months was 0.23 mm; this remained statistically unchanged both at 1 year: 0.20mm (p=0.69, 95% UCL of the difference: +0.15mm) and 2 years: 0.25mm (p=0.77, 95% UCL of the difference: +0.10mm).

Conclusion: It is generally recognized that femoral head penetration of more than 0.1 mm per year can result in osteolysis. The purpose of cross linking polyethylene is to reduce wear to below this level. The results of this study show that after an initial bedding in of approximately 0.2 mm, femoral head penetration is not detectable over the subsequent 18 months. Further follow-up is underway to confirm that this promising reduction in wear is maintained.


G. Yves Laflamme Mathieu Carrier Louis Roy Paul Kim Stephane Leduc

Purpose: To determine if early functional assessment correlates and/or predicts long term function after hemi-arthroplasty for displaced femoral neck fractures.

Method: We evaluated prospectively fifty six (56) patients with Garden-type III and IV femoral neck fractures in a Level 1 trauma center with a minimum of two years follow-up. Validated functional measures including Lower Extremity Measure (LEM) and Timed Up and Go (TUG) were used. Score progression was recorded and analyzed in relation to patient baseline data.

Results: The regression analysis between TUG times at three months and the mean LEM scores at two years follow-up showed a good correlation (R2=0.659). Further analysis determined that patients with TUG times of less than twenty (20) seconds at six weeks of follow-up had a mean LEM score significantly higher at both one year (81.5 vs 56.2; p< 0.001) and two years follow-up (77.1 vs 41.8; p< 0.001). This difference between mean LEM scores was also noted for the TUG values at three months.

Conclusion: The TUG test is an early clinical indicator of future function. Innovative clinical approaches such as the one demonstrated in this study to anticipate future function will contribute to increasing efficiency in the overall management of this growing patient population.


Michael Gross David Amirault Allan Hennigar Michael J Dunbar

Purpose: To determine if MIS for primary hip replacement surgery increases the risk of long term aseptic loosening as predicted by implant micromotion measured with radiostereometric analysis (RSA).

Method: Ninety patients undergoing primary THA for osteoarthritis (exclusion criteria: post-traumatic arthritis, rheumatoid arthritis, hip dysplasia, previous hip infection) were randomized to undergo THR surgery utilizing the standard direct lateral approach (n=45; 24 male; age=58 yrs; BMI=27) or MIS via a one-incision direct lateral approach using specific instrumentation (n=45; 23 male; age=55; BMI=29). Uncemented acetabular and femoral (ProfemurZ) components were used with ceramic on ceramic bearings. The femur was marked with 9 tantalum beads placed in the greater trochanter, lesser trochanter, and femoral shaft distal to the tip of the prosthesis. Post-operative care was be standardized according to the care maps at our institution. Primary outcome measure was femoral stem MTPM (maximum total point motion) measured using Model-based RSA. Stereo supine X-rays were taken before weight bearing and 3, 6, and 12 months postoperatively. At the same time intervals Harris Hip Score, Oxford-12, WOMAC, and SF36 questionnaires were administered. Rates of infection, dislocation and revision were recorded.

Results: Eleven patients were lost to follow-up (4 due to missing post-op exams; 5 did not have enough beads placed during surgery; 2 were revised due to failure of the ceramic femoral head). There were five long neck fractures at 17–30 months postop that are reported in detail in a related abstract. There were no differences between groups for all outcome measures. Mean MTPM at 12 months was 2.5mm (SD=1.8mm) for the MIS group and 2.6mm (SD=1.2mm) for the standard group.

Conclusion: No difference between groups at one year indicates MIS for uncemented primary THR through a direct lateral approach does not appear to negatively affect stability of the femoral stem. Although promising, these results require confirmation with 2-year RSA data.


Sanket Diwanji Martin Lavigne Étienne Belzile François Morin Alain Roy Pascal-André Vendittoli

Purpose: Tribological studies of hip arthroplasty suggest that larger diameter metal-on-metal (MOM) articulations would produce less wear than smaller diameter articulations. Other advantages of these large femoral head implants include better stability with lower dislocation rates and improved range of motion. The aim of the present study was to compare chromium (Cr), cobalt (Co) and titanium (Ti) ion concentrations up to one year after different large diameter MOM total hip arthroplasties (THAs).

Method: One hundred and twelve patients were randomized to receive large (femoral head > 36 mm diameter) metal-on-metal articulation THA (LDH) from one of the following companies: Zimmer, Smith & Nephew, Biomet or Depuy. Samples of whole blood were collected pre-operatively and post-operatively at six months and one year. Cr, Co and Ti concentrations were measured by high-resolution mass spectrometry in an independent laboratory. All LDH implants have a modular Cr-Co tapered sleeve for leg length adjustment, except for Biomet with its sleeve made of Ti. All groups had Ti stems, and Zimmer and Biomet had, in addition, a Ti acetabular porous surface for secondary fixation. We undertook statistical analysis (SPSS 14.0) with p< 0.05 as significant.

Results: The groups were comparable in respect to pre-operative parameters (age, gender ratio, body mass index, etc.) as well as post-operative functional scores at six months and one year. We found that Biomet, Depuy and Smith & Nephew LDH had similar Co ion levels at 12 months post-op with 1.5, 1.4 and 1.6 ug/L, respectively. Durom LDH had the highest Co level with 2.3 ug/L (p< 0.01 versus the three other groups). The highest Ti ion levels were observed in the Zimmer group with 3.2 ug/L (p< 0.01 versus the three other groups) and the Biomet group with 2.0 ug/L (p=0.01 versus Zimmer and NS versus the other 2). Ti levels tripled versus pre-op for BHR and ASR (0.5 versus 1.5 and 0.5 versus 1.4 ug/L).

Conclusion: Different implant factors may influence metal ion levels measured in whole blood: articular surface wear and implant passive corrosion. Zimmer’s Durom LDH presents higher Co levels than the other groups. Since previously-published Durom hip resurfacing (same bearing characteristics as Durom LDH) showed much lower Co ion results, the modular sleeve may be incriminated. The plasma-sprayed acetabular surface of Zimmer’s and Biomet’s components seems to be responsible for the significant difference in Ti versus the other implants. Biomet’s plasma-sprayed Ti appears to be less prone to corrosion than Durom’s plasma spray coating. When evaluating metal ion release from MOM THA, total metal load from the implants should be considered, and newer implant designs should be evaluated scientifically before their widespread clinical use. LDH-THA should be seen as an improvement and should not be blamed as the source of metal ion release when a specific implant produces unsatisfactory results.


Daniel Varin Mario Lamontagne Melanie Beaulieu Paul E Beaulé

Purpose: It is thought that the anterior approach better restores gait mechanics after total hip arthroplasty (THA) being a pure intermuscular/internervous approach. The purpose of this study was to compare three-dimensional (3-D) kinematics and kinetics of THA patients that had an anterior (ANT) vs. a lateral (LAT) approach. It is hypothesized that the ANT group will exhibit fewer differences than the LAT group when compared to a control group (CON).

Method: Fifty-four participants were divided into three groups of 18: ANT (12 women, 6 men; age: 60.9 ± 6.2 yr; BMI: 28.8 ± 4.9 kg/m2), LAT (10 women, 8 men; age: 65.2 ± 6.3 yr; BMI: 27.5 ± 5.1 kg/m2) and CON (9 women, 9 men; age: 63.9 ± 4.4 yr; BMI: 25.4 ± 3.2 kg/ m2). All THA patients had primary unilateral THA due to osteoarthritis and had no other lower-limb pathology. They were evaluated five to 17 months after surgery. 3-D kinematics and kinetics were obtained using a nine-camera motion analysis system and a force platform placed on the first step of a staircase. Each participant performed three trials of stair ascending. A series of one-way ANOVAs were used to compare peak angles, range of motion (ROM), peak resultant joint forces as well as moments and powers of the hip, knee and ankle joints in all three planes.

Results: Most differences occurred during transitions between double- to single-legged stance. Both LAT and ANT groups ascended the staircase with a more abducted hip than the CON group, resulting in reduced hip abduction moment. This could be the result of the implant’s position and its potential abductor lever arm reduction. Both groups also showed reduced peak internal rotation moments. These results have previously been found in THA patients who have been operated through lateral and posterior approaches, and are thought to be caused by hip abductor muscle damage inherent to the surgical approach. However, only the LAT group had lower compression forces at the hip, knee and ankle joints compared to the CON group. This indicates that LAT group uses a strategy that reduces the loading on the operated leg, which may be due to the detachment of the anterior third of the gluteus medius. It could be speculated that the muscle sparing aspect of ANT approach allows patients to load adequately their operated leg, even if their frontal plane kinematics and kinetics are altered.

Conclusion: Some studies have failed to find differences with the anterior approach. However, they have only looked at spatiotemporal gait parameters. 3-D kinematics and kinetics can provide a more detailed assessment of function and detect more subtle differences. In this study, 3-D biomechanical analysis has detected differences in THA patients operated through different surgical approaches during stair ascent. The data obtained showed similar frontal plane kinematics for both groups, but different lower-limb compression forces. This study supports the use of the anterior approach for better restoration of function after total hip arthroplasty.


Craig White Jamie Lopez Castellaro Paul E Beaulé Paul Kim

Purpose: Although femoral neck fractures remain a concern in terms of short term failures for hip resurfacing, acetabular component position and fixation are increasingly being recognized as causes of mid term failures for hip resurfacing. The purpose of our study was to evaluate the migration pattern of a cementless acetabular component for a metal on metal hip resurfacing.

Method: Between January 2006 and June 2007, 130 patients underwent metal on metal hip resurfacing; 66 hips in 60 patients were included in this analysis. Forty-eight patients were male and 12 were female, with a mean age of 50 (range, 32–66). Ninety-five percent of the surgeries were performed for osteoarthritis. All surgeries were performed by two surgeons using the Conserve Plus (Wright Medical Technology, Memphis, TN) hip resurfacing system. The acetabular component is a monoblock cobalt chrome with a porous beaded surface for osteointegration. In all cases acetabular migration was measured both vertically and horizontally, on serial radiographs using the computer-assisted Ein Bild Röntgen Analyse (EBRA) method. A minimum of three comparable radiographs is necessary for calculating the migration curves. We scored medial migration as negative horizontal movement.

Results: At a mean follow up 25.3 months (range, 24–36 months), each hip had an average of 5.1 radiographs for analysis. The software excluded two cases for poor comparability ending finally with 64 cases for the analysis. Eighty-seven point five per cent of the cups showed less than 1 mm migration in the medium-lateral axis and 54.7% less than 1 mm in the vertical axis. Seventy-seven percent of the cups showed a combined migration of less than 2 mm in the observation period, without radiolucencies, leaving 23% of the acetabular components with 2 mm or greater of component migration. One of these cases required revision for aseptic loosening at 34 months.

Conclusion: In our study the majority of the acetabular components were stable with some of the migration observed secondary to lack of complete initial seating due to the rigidity of the shell. Krismer et al did report on the migration of the PCA shell (also a porous beaded cobalt-chrome shell) using EBRA, with 27.5% of the shells demonstrating > 1 mm of migration. Although hip resurfacing has only mid term followup, results have been good to excellent. Caution should still be maintained since the higher frictional torque generated by the larger femoral head size as well as the nanometer size particles could negatively affect long term fixation of the acetabular component.


Kevin A Hildebrand David A Hart

Purpose: Elbow osteoarthritis (OA) is characterized by a loss of elbow motion secondary to joint capsular hypertrophy and osteophyte formation. Previous work on joint capsules in post-traumatic (PT) elbow joint contractures has shown that alterations in cell populations (increased number of alpha-SMA positive myofibroblasts), matrix molecule and enzyme, and growth factor mRNA profiles are associated with loss of elbow motion in this condition. The objective of this study was to determine whether alterations in joint capsule parameters were similar or different in two etiologies of human elbow contractures, primary OA and PT.

Method: Posterior elbow joint capsules were obtained from eight male patients with primary elbow OA (age 52±12 yr ), five male patients with chronic (> 1 year) PT (age 47±12 yr ) and four male organ donors free of OA and contractures (age 43±10 yr ). RNA was extracted for subsequent real-time PCR for alpha-SMA, interleu-kin-1beta, MMP-1, MMP-3, collagen type III, biglycan, versican, tenascin C, TIMP-1, MMP-2, iNOS, COX-2, glyceraldehyde – 3 phosphate dehydrogenase (GAPDH) and 18S. 18S was used to normalize gene expression. Statistical comparisons used a oneway ANOVA followed by posthoc Tukey test. Significance was p < 0.05.

Results: The mRNA levels in the OA and PT capsules were increased compared to controls in most cases. This includes the major matrix molecule collagen I and the myofibroblast marker alpha-SMA, the growth factors TGF-beta1 and CTGF plus decorin, the injury response elements (collagen III, biglycan, versican, tenascin C) as well as TIMP-1 and MMP-2. The housekeeping gene GAPDH was similar in all 3 groups as was COX-2, while iNOS was elevated in both groups characterized by contractures. When comparing the two contracture groups, the mRNA levels were similar for some molecules while differences were evident in other instances. In PT, alpha-SMA and collagen I were greater than in OA. Conversely, in the OA group, the growth factors and matrix enzyme systems exhibited higher levels than PT.

Conclusion: In this study of human elbow joint capsules, we have shown that relative mRNA levels for markers of myofibroblasts, major matrix components, injury response elements and selected growth factors are significantly elevated in elbow OA and post-traumatic contractures when compared to age matched organ donor controls free of contractures. When comparing the OA and PT groups, the injury response molecules were elevated to similar relative levels. The OA group had greater increases in the growth factors and many of the matrix enzymes / inhibitors measured, while the PT group had greater increases in the myofibroblast marker alpha-SMA and the major matrix molecule collagen I. Thus in general matrix, growth factor and cellular properties appear to be preferentially altered in the two conditions studied when compared to control tissues, strengthened by the fact that the housekeeping gene GAPDH had similar relative levels in all 3 groups.


Graham JW King Gillian S Greeley Brendon JB Beaton Louis M Ferreira James A Johnson

Purpose: This in-vitro study examined the effect of simulated Colles fractures on load transmitted to the distal ulna, using an in-line load cell. Our hypothesis was distal radial fracture malposition will increase distal radial ulnar joint (DRUJ) load relative to the native position of the radius.

Method: Eight fresh frozen upper-extremities were mounted in a motion simulator which enabled active forearm rotation. An osteotomy was performed just proximal to the distal radioulnar joint, and a 3-degree of freedom modular appliance was implanted which simulated Colles type distal radial fracture deformities. This device allowed for accurate adjustment of dorsal angulation and translation (0, 10, 20 and 30 degrees dorsal angulation and 0, 5 and 10mm dorsal translation both isolated and in combination). A 6-DOF load cell was inserted in the distal ulna 1.5 cm proximal to the ulnar head to quantify DRUJ joint forces. Distal ulnar loading was measured following simulated distal radial deformities with both an intact and sectioned triangular fibrocartilage complex (TFCC).

Results: The maximum resultant transverse distal ulnar load occurred during active forearm pronation and supination. Increasing magnitudes of dorsal angulation and translation of the distal radius increased loading in the distal ulna. For pronation with the ligaments intact, the transverse resultant load for the non-fracture, native positioning was significantly lower (p< 0.05) than the majority of malpositioned cases except for the translations only (not combined with angulation). However, all fracture orientations for supination had an increased effect on the resultant loading (p< 0.05) when ligaments were intact. Greater forces were measured in the distal ulna when the TFCC intact relative to TFCC sectioning. Sectioning the TFCC eliminated the effect of fracture malposition for both pronation and supination. The range of maximum transverse force for intact pronation and supination was between 118& #61617;34N and 130& #61617;39N, respectively. Similarly, for sectioned pronation and supination, the maximum transverse forces were and 93& #61617;40N and 89& #61617;24N, respectively.

Conclusion: Malpositioning of distal radial fractures in dorsal translation and angulation was found to increase forces in the distal ulna, which may be an important source of residual pain following malunion of Colles fractures. Healing of the distal radius in an anatomic position resulted in the least forces. Sectioning the TFCC released the tethering effect of the radius on the ulna, decreasing DRUJ force. This is the first study of its kind to attempt to quantify the forces at the DRUJ as a result of Colles fractures, and these early findings provide important baseline information related to the biomechanics of the DRUJ.


Jennifer Ng Emily A Lalone Colin P McDonald Louis M Ferreira Graham J King James A Johnson

Purpose: The identification of anatomical landmarks is an important aspect of joint surgery, to ensure proper placement and alignment for implants and other reconstructive procedures. At the elbow, the center of the capitellum (derived via a digitization of the surface and subsequent sphere fitting) has been well established as a key landmark to identify the axis of rotation of the joint. For some cases, and in particular minimally invasive surgery, only small regions of the capitellum may be exposed which may lead to errors in determining the centre. The purpose of this study was to identify the optimal location of digitizations of the capitellum.

Method: Twenty-five fresh frozen cadaveric distal humeri (19 left, 6 right) were studied. Using an x-ray computed tomography scanner, volumetric images of each specimen were acquired and used to reconstruct a 3-dimensional digital model of the specimen using the Visualization Toolkit (VTK). A sphere-fit algorithm was used to determine the centre of the spherical capitellum based on manually chosen (digitized) points across the 3D capitellar surface. The true geometric centre was located by digitizing points across the entire capitellar surface. Three sub-regions of the capitellum, commensurate with typical surgical approaches with minimal dissection, were then digitized. These were superior anterior lateral (SAL), inferior anterior lateral (IAL) and a combination of these two regions. These regions were compared to the true center using a 1-way Repeated Measures ANOVA with significance set to p = 0.05.

Results: Digitizations of only SAL and IAL sub-regions resulted in the largest differences relative to the true centre: SAL = 3.9±3.4 mm, IAL = 4.2±3.4 mm, (p < 0.0005). There was no difference between SAL and IAL (p = 1.0). Digitization of the combined SAL + IAL regions, while significantly different from the entire capitellum, resulted in the smallest mean difference of 0.87±0.84 mm.

Conclusion: These data show that the region of digitization affects the accuracy of predicting the capitellum centre. In a previous study by our group, we showed that an accurate determination of the centre of a sphere can be achieved with a small surface area of digitization. In the current study, the large errors that occurred when a small surface was digitized (i.e. SAL and IAL alone), are in all likelihood, due the non-spherical nature of the capitellum. In summary, while the most precise method in locating the true centre is to digitize the entire capitellar surface where possible, an alternative approach is to digitize both the superior and inferior anterior lateral regions.


David Pichora Manuela Kunz Burton Ma John F Rudan Randy E Ellis Hisham Alsanawi

Purpose: The purpose of this clinical trial was to investigate the accuracy of a novel method for computer-assisted distal radius osteotomy, in which computer-generated patient-specific plastic guides were used for intra-operative guidance. Our hypothesis was that these guides combine the accuracy and precision of computer-assisted techniques with the ease of use of mechanical guides.

Method: In a consecutive series of 9 patients we tested the accuracy of the proposed method. Prior to surgery, CT scans were obtained of both radii and ulnae in neutral rotation. Three-dimensional virtual models for both the affected and unaffected radius and ulna were created. The models of the unaffected radius and ulna were reflected to serve as a template for the correction. Custom-made software was used to plan the correction. The locations of the distal and proximal drill holes for the plate were saved and the locations of the distal holes before the osteotomy were determined. The design of a patient-specific instrument guide was calculated, into which a mirror image of intra-operative accessible bone structure of the distal radius was integrated. This allowed for unique positioning of the guide intra-operatively. For each planned drill location a guidance hole was incorporated into the guide. A plastic model of the guide was created using a rapid prototyping machine. Intra-operatively, a conventional incision was made and the guide was positioned on the distal end of the radius. The surgeon drilled the holes for the plate screws into the intact radius. The guide was removed and the surgeon performed the osteotomy using the conventional technique and shaved the bone from the distal radius fragment to accommodate the plate. Using the pre-drilled holes the plate was affixed to the distal radius fragment. The distal fragment was reduced until the proximal screw holes in the plate aligned with the pilot holes in the bone. To analyze the accuracy of the intra-operative procedure we compared the post-operative alignment of the radius with the planned alignment. A lateral and an A/P digitally reconstructed radiograph (DRR) of the plan were calculated. These DRRs were used to evaluate the radial inclination, the volar tilt and the ulnar variance of the planned alignment. Post-operative lateral and A/P X-Rays were used to determine the same three post-operative radiographic indices. The post-operative values were compared with the planned values.

Results: We found an average deviation for the radial inclination of 0.5°(StDev 1.8), for the volar tilt of 0.7°(StDev 2.3), and for the ulnar variance of 0.8mm (StDev 1.9).

Conclusion: These results show that the computer-generated instrument guides accurately achieved the planned alignment. The guides were easy to integrate into the surgical workflow and eliminated the need for intra-operative fluoroscopy for guidance of the procedure.


Anthony Miniaci Stephen D Fening

Purpose: Osteochondral allograft transplantation for the treatment of osseous defects to the humeral head has recently grown in popularity. Because only a portion of the articulating surface of the humeral head is replaced, conformity of the allograft to the native surface is imperative to restore the natural geometry of the joint. To achieve proper conformity, it is essential that the curvature of the humeral head of the allograft tissue match that of the native tissue. Curvature determination is also important for shoulder replacement procedures. Curvature of the humeral head is difficult to directly measure in allograft specimens. As a result, predictive measurements, such as the maximum length of the humerus are used to predict this curvature. The purpose of this study was to investigate the value of various anthropometric measurements for predicting humeral head curvature. We hypothesized that the maximum length of the humerus would be the most predictive of humeral curvature.

Method: 60 (28 female, 32 male) cadaveric humeri were obtained from the Hamann-Todd Human Osteological Collection. Specimens ranged from 20 to 35 years of age at the time of death (27.9 ± 4.5, mean ± SD). Specimens from this collection include height and weight as collected at the time of death. All specimens were scanned with a 3-dimensional laser scanner (NextEngine, Santa Monica, California, USA). This scanner has been shown to be accurate to within 0.005 inches. Linear measurements (maximum humeral length, epicondylar breadth) were made according to the recording standards for skeletal remains. Both measurements were made by choosing points on the 3-dimensional scan, rather than the traditional osteometric board. Humeral head curvature was determined by a custom computational code to fit a sphere to the articulating surface of the humerus. Data analysis was performed in Minitab (version 13, State College, PA, USA). A linear regression was performed for each predictive measurement. A stepwise linear regression with forward and backward substitution was performed for the most predictive variables from the initial linear regression.

Results: The most predictive factors (R^2 > 0.5) were epicondylar breadth, height, maximum humeral length, and gender. Based on the linear regression coefficients, these four factors (all normalized) were included in a forward and backward stepwise regression (alpha to enter and remove = 0.15). The resulting equation (shown below) had an R^2 values of 0.807. Humeral Diameter = 0.894 + 0.048*(epicondylar breadth) + 0.043*height – 0.020*gender

Conclusion: Of the predicted measurements evaluated, patient height, epicondylar breadth, and gender were most correlated with humeral head curvature. Including these three factors in a linear regression model increased the R2 value to 0.807. If only a single measurement can be used to size the humeral curvature, patient height will give approximately the same accuracy as epicondylar breadth, and can more easily be obtained.


Luke W Harris Babak Shadgan Darlene Reid Scott K Powers Peter J O’Brien

Purpose: It is well established that skeletal muscle ischemia followed by reperfusion induces oxidative damage, metabolic stress, and an inflammatory response. This ischemia-reperfusion injury has been studied extensively in experimental models and, importantly, in the clinical setting where it is associated with tourniquet (TQ) inflation during orthopedic trauma surgery. Of particular clinical concern is the notion that reperfusion upon TQ release is central to oxidative injury, since release necessarily follows surgery. Consequently, the effects of ischemia alone, without reperfusion, is poorly documented. That is, it remains unknown what are the effects of muscle ischemia, per se, on muscle properties that could influence functional recovery postoperatively or what preventative measures might be taken to minimize the potentially deleterious effects of the ischemic period alone. Hence the purpose of this study was to investigate changes in myofibrillar contractile protein oxidation over the course of TQ-induced leg muscle ischemia during orthopedic trauma surgery.

Method: Among patients with unilateral ankle fractures requiring surgery at our institution, 24 subjects gave informed consent to participate. All subjects underwent standard general anesthesia. PRE surgical biopsies were collected from the peroneus tertius muscle (PT) immediately after TQ inflation and incision of the skin and underlying connective tissue. POST surgical biopsies were collected from the same muscle immediately before TQ release. Oxidation of PT myosin, actin, and total protein was quantified using Western blot analysis for 4-hydroxynonenal (4-HNE) modified proteins. Results are reported as mean ± standard deviation.

Results: Total TQ time ranged from about 21 to 84 min (50.5±16). As anticipated, in PRE biopsies compared to POST biopsies there were large increases in the PT content of 4-NE modified myosin (174.4±128%; P< 1×10-6), actin (223.7±182%; P< 5×10-9), and total protein (567.5±378%; P< 5×10-7). Intriguingly, there was a much greater increase in PT protein oxidation in males than in females (43.3% difference; P< 0.05), although there was no relationship observed between PT protein oxidation and subject age. Surprisingly, there was no significant relationship between muscle protein oxidation and duration of the TQ-induced ischemia.

Conclusion: TQ-induced skeletal muscle ischemia for 21 to 84 min during orthopedic trauma surgery leads to considerable oxidative muscle injury as measured by muscle protein oxidation, including of the functionally relevant contractile proteins myosin and actin. This injury occurs even without reperfusion. Interestingly, the extent of oxidative muscle injury appears to be influenced by gender, but is not dependent upon the duration of ischemia.

FUNDING: MSFHR, COF, BCLA.


Emily A Lalone Colin P McDonald Louis M Ferreira Graham King James Johnson

Purpose: Current techniques for the investigation of elbow stability following injury or surgical interventions rely on kinematic descriptors. Typically, the motion pathways of the bones are employed to describe the effect of various clinical variables on alignment joint stability. This study describes a new approach to better visualize joint motion pathways that relates the anatomical geometry of the joint, obtained using medical imaging, with the recorded motion of the joint. The clinical aim of our study was to use this approach to investigate the effect of radial head resection and subsequent radial head arthroplasty on joint kinematics and elbow stability.

Method: Five fresh-frozen cadaveric specimens were employed. Computed tomography (CT) scans of each upper extremity were obtained to create a three-dimensional model of the joint. Simulated active elbow flexion with the arm in the valgus gravity loaded position was achieved using an upper arm simulator previously developed in our laboratory. Receivers from an electromagnetic tracking device were attached to the humerus and ulna in order to record their relative motion. Sutures were secured to the tendons of relevant muscles, which were connected to servomotors and pneumatic actuators, used to simulate motion. Kinematic data was collected with the radial head intact, radial head resected and following placement of metallic radial head implant. A repeated-measures analysis of variance was used to detect statistical differences. After testing, each specimen was denuded of all soft tissue and disarticulated. Fiducial markers were attached to the humerus and the ulna. The joint was then re-imaged in the CT scanner to obtain a volumetric image of each fiducial. Using the kinematic data recorded during simulated motion, and the knowledge of the position of each fiducial, a direct visualization of the recorded motion, using the 3D models was obtained. The bony position was then compared to the traditional graphical kinematic analysis examining changes in valgus angulations throughout the arc of motion.

Results: We observed a close agreement between the kinematic output and the registered bony 3D models showing the joint position. Following resection of the radial head, in the valgus dependent position, there was an increase in the valgus angulation of the ulna with respect to the humerus (p< 0.05).

Conclusion: Using this visualization approach, these changes in bony alignment were readily observed and understood visually in the 3D model of the ulna. Unlike the traditional graphical approach used to investigate elbow stability, this technique allows for the representation of coupled motion (rotation) of the bones. This technique also permits direct visualization the relative position of the bones within the joint, hence improving the overall understanding of joint motion.


Babak Shadgan Darlene Reid Peter J O’Brien

Purpose: Near-infrared spectroscopy (NIRS) detects changes in chromophore concentrations of oxygenated (O2Hb) and deoxygenated hemoglobin (HHb) in target tissues approximately 2 to 3 cm below the skin. The main purpose of this study was to non-invasively measure skeletal muscle oxygenation in the leg during and after tourniquet (TQ)-induced ischemia using continuous wave NIRS. Secondarily, we aimed to assess the sensitivity, specificity, and reliability of this optical technique for detection and continuous monitoring of changes in muscle oxygenation and hemodynamics during TQ-induced ischemia throughout orthopedic surgery.

Method: Consented patients aged 19–69 (n=21) with unilateral ankle fracture requiring emergency or elective surgery at our institution were recruited. All patients underwent standard general anesthetic. A pair of NIRS probes was fixed over the midpoint of the tibialis anterior muscle (TA) of both the fractured and healthy legs. A thigh TQ was applied to the injured leg and inflated to 300 mmHg. Using the NIRS apparatus coupled to a laptop with data acquisition software, changes in O2Hb, HHb, and total hemoglobin (tHb) levels in the TAs of both legs were measured at 10 Hz before and during TQ inflation, and after release until values returned to baseline. In each surgery the TQ was released when arterial obstruction was no longer required by the clinical team. Data are reported as mean±SD.

Results: Changes in O2Hb, HHb, and tHb were successfully collected, stored and transmitted for graphic display in all subjects. TQ time (ischemia interval) varied among subjects, from 1245 s to 4431 s (2753±854). NIRS measured a progressive increase in HHb (2.6±2 μmol/L) during the first minute of TQ inflation and a sharp increase in O2Hb (23.3±12 μmol/L) during the first minute of leg muscle reperfusion (after deflation). Following TQ inflation a progressive increase in HHb (24.2±10.3 μmol/L) with a concomitant decrease in O2Hb (mean – 24.4±8 μmol/L) in the under-TQ TA were consistent across subjects. These changes in ΔHHb and ΔO2Hb began to reverse immediately after TQ deflation. Significant correlations were observed between ischemia interval and, respectively, oxygenation recovery time (r2=0.84) and changes of deoxygenated hemoglobin (r2=0.57).

Conclusion: We demonstrated that, following TQ inflation and deflation respectively, NIRS can sensitively monitor muscle deoxygenation and reoxygenation. Consistent patterns of ΔHHb and ΔO2Hb occurred during TQ-induced ischemia in all subjects. These data confirm that near infrared spectroscopy is useful for the non-invasive detection and monitoring of muscle ischemia. These results indicate that it may be useful to investigate the efficacy of NIRS in the early detection of muscle ischemia or hypoxemia in conditions such as compartment syndrome.

FUNDING: MSFHR, COF, BC Lung.


Kevin A Hildebrand Michael J Monument

Purpose: The presence of hemarthrosis during joint injury is a potential inciting stimulus in the genesis of joint capsule fibrosis. Using a rabbit model of posttraumatic knee joint contracture, our hypothesis was that, bone marrow-derived elements of hemarthrosis rather than simply the presence of blood in the joint, trigger the induction of capsule fibrosis in post-traumatic joint contracture.

Method: 35 Skeletally mature New Zealand White female rabbits (12–18 months old, 5.5 ± 0.5 kg) were randomly assigned to one of five groups: Immobilization-Only (IMO), Immobilization+ Bone Marrow (IMBM), Immobilization+ Peripheral Blood (IMPB), Bone Marrow-Only (BMO), and Controls. Surgeries: Immobilization groups had one knee joint fixed at full flexion with a Kirschner wire drilled through the tibia, passed posterior (extra-articular) to the knee joint and bent around the femur. Bone marrow groups had cortical windows removed from the non-articular cartilage portion of the medial and lateral femoral condyles. In the IMPB group, autologous peripheral venous blood was injected into the immobilized knee joint to recreate a non-traumatic hemarthrosis. The control group did not have any intervention. Joint angle measurements: After 8 weeks, rabbits were euthanized, all muscular tissue was removed and maximum extension angle of the joints with intact capsule was measured using a standard torque applied via a custom made rabbit knee gripping device attached to a MTS TestStar II. Each joint was cycled 5 times (0.2 Nm) and the average of 5 cycles was calculated. Statistical analysis consisted of a one-way ANOVA with posthoc Scheffe test (significance p < 0.05). Data are presented as mean +/ − standard deviation.

Results: The IMBM (n=8) and IMPB (n=7) groups had significantly greater contractures (52 +/ − 12 and 58 +/ − 13 degrees, respectively) when compared to the BMO (n=7) and control (n=6) groups (32 +/ − 10 and 32 +/ − 13 degrees, respectively). The IMO group had average contracture measures of 44 +/ − 15 degrees. There was no statistically significant difference between the IMBM and IMPB groups.

Conclusion: The present study showed differences in the contracture severity of the immobilized knees associated with hemarthrosis compared to other experimental and control groups. There does not appear to be a difference whether the hemarthrosis arose from a fracture (bone marrow) versus peripheral blood in rabbits. Future work will look at reversibility of contractures in the various groups. Studies on the joint capsule will evaluate myofibroblast numbers in concert with mast cell and neuropeptide distribution based on our previous work. Such knowledge will aid the prevention and treatment of the difficult and disabling problem of contracture formation after joint injury.


Matthew G Teeter Douglas D Naudie David D McErlain Jan-Mels Brandt Xunhua Yuan Steven JM MacDonald David W Holdsworth

Purpose: This study develops and validates a technique to quantify polyethylene wear in tibial inserts using micro-computed tomography (micro-CT), a nondestructive high resolution imaging technique that provides detailed images of surface geometry in addition to volumetric measurements.

Method: Six unworn and six wear-simulated Anatomic Modular Knee (DePuy Inc, Warsaw, IN) tibial inserts were evaluated. Each insert was scanned three times using micro-CT at a resolution of 50 μm. The insert surface was reconstructed for each scan through automatic segmentation and the insert volume was calculated. Gravimetric analysis was also performed for all inserts, and the micro-CT and gravimetric volumes were compared to determine accuracy. The utility of surface deviation maps derived from micro-CT was demonstrated by co-registering a worn and unworn insert. 3D deviations were measured continuously across the entire insert surface, including the articular and backside surfaces.

Results: The mean percent volume difference between the micro-CT and gravimetric techniques was 0.04% for the unworn inserts and 0.03% for the worn inserts. No significant difference was found between the micro-CT and gravimetric volumes for the unworn or worn inserts (P = 0.237 and P = 0.135, respectively). The mean coefficient of variation for volume between scans was 0.07% for both unworn and worn inserts. The map of surface deviations between the worn and unworn insert revealed focal deviations exceeding 750 μm due to wear.

Conclusion: Micro-CT provides precise and accurate volumetric measurements of polyethylene tibial inserts. Quantifiable 3D articular and backside surface deviation maps can be created from the detailed geometry provided by the technique. Compared to coordinate mapping, micro-CT provides 10 times greater surface sampling resolution (50 μm vs 500 μm) across the entire insert surface. Micro-CT is a useful analysis tool for wear simulator and retrieval studies of the polyethylene components used in total knee replacement.


David AJ Wilson Cheryl Hubley-Kozey Michael J Dunbar Janie L Astephen Wilson

Purpose: The goal of this study was to investigate if musculoskeletal activation patterns measured with electromyography (EMG) are predictive of migration of total knee replacements (TKR) measured with radiostereometric analysis (RSA).

Method: 37 TKR patients who were part of a larger randomized controlled RSA trial were recruited to this study. Study participants had been randomized to receive the Nexgen LPS Trabecular Metal tibial monoblock component (n = 19), or the cemented NexGen Option Stemmed tibial component (n = 18) (Zimmer, Warsaw IN). Ethics approval was received from the institutional review board. In the week prior to their surgery, the patients went to the dynamics of human motion laboratory and underwent EMG data collection. Surface electrodes were placed over the vastus lateralis, vastus medialis, rectus femoris, the lateral and medial hamstrings, and the lateral and medial gastrocnemius using standardized placements (Hubley-Kozey et al., 2006). The variability in subject EMG patterns was captured with a set of discrete scores that represented weightings on objectively-extracted features of the gait waveform data using principal component analysis (PCA). Within four days of surgery and at six months post-operatively, patients had bi-planar knee x-rays taken. RSA analysis was performed with MB-RSA (MEDIS, Leiden). RSA results were reported as maximum total point motion (MTPM), and six degrees of freedom translations and rotations at six months.

Results: A correlation was found between the third principle component of the lateral gastrocnemius muscle (representing high gastrocnemius activation in late stance) and the anterior migration of the component (R2=0.247 P=0.002). A correlation was found between the vastus medialis principle component three (representing low vastus medialis activation in late stance) and the anterior migration of the component (R2= 0.338, P=0.000). A stepwise regression model was developed for anterior migration of the tibial component. To reduce the number of terms in the model only the two EMG variables that were correlated with anterior migration, implant type and BMI were entered leaving four possible terms. The stepwise regression eliminated all variables but the lateral gastrocnemius and the vastus medialis. The regression equation was Anterior-Posterior Migration = 0.01 +0.12*Vastus Medialis PC3 + 0.074*Lateral Gastrocnemius PC3 (R2=0.487, R2 Adj=0.457, P< 0.0001)

Conclusion: It has previously been shown that anterior shear on the tibial component of TKR is temporally localized to the last third of stance phase of gait. Both the gastrocnemius and vastus muscle groups have the ability to produce large anterior posterior shear on an the knee during late stance. This result shows that variables which capture the temporal activation patterns of these muscles preoperatively are related to the migration of the tibial component of TKR postoperatively. This may have implications for rehabilitation of these patients.


Michèle Angers Étienne L Belzile Michel Malo Pascal-André Vendittoli Marc Bouchard

Purpose: Bone stress transmission by an implant has been demonstrated to be inversely proportional to its rigidity. Since trabecular metal has a high elasticity modulus, it is hypothesised that it should have a preservative impact on bone mineral density (BMD) loss. No current studies prospectively compare BMD variations using such implants.

Method: A randomized study recruiting 65 patients with osteoarthritis of the knee, were assigned to a cemented titanium or a non-cemented trabecular metal tibial base plate. Each patient had a DXA scan of the proximal tibia on the TKA side at two weeks, six months, one and two years follow-up. Analytic methods for DXA scans were standardized (Variation coefficient=0,59–0,84%), and BMD variation compared between groups using the Student t-Test.

Results: Versus early post operative evaluation, BMD loss was found in the two groups. Fixed effects on BMD, such as patient’s height (p< 0.001) and tibial implant size (p=0.04) were demonstrated. Patella resurfacing and polyethylene thickness had no effect on BMD. BMD loss was more important under titanium implants (−30.9%) than trabecular metal implants (−6.3%). The most affected area was the metaphysis (p=0.002) compared to the diaphysis (p=0.054).

Conclusion: Trabecular metal tibial base plate seems to diminish BMD loss under tibial implant compared to traditional titanium base plate. A long-term study will be necessary to determine the tibial trabecular metal component survival rate.


Mark Gatha Frank Noftall Roderick D Martin Peter Rockwood Proton Rahman

Purpose: Intra-articular corticosteroid injections is a well established treatment for knee osteoarthritis (OA). However, only 60% of patients have a good short-term response and about 20% of patients have a satisfactory long-term response. Genetic variants may play a role in predicting response to corticosteroids. A genetic variant of the macrophage inflammatory factor (MIF) (a physiologic counter-regulator of glucocorticoids), has been associated with poor clinical response in various inflammatory diseases. No studies to date have evaluated the effect of this variant on steroid injections for knee OA. We set out to determine the impact of the – 173(C) variant of the MIF gene on clinical response to intra-articular injections for knee OA.

Method: 80 patients with Kellgren-Lawrence Grade 2–3 OA of the knee were prospectively followed for three months following a standard dose of steroid injection. All patients were genotyped for the – 173 variant of the MIF gene. WOMAC questionnaires for knee OA were done at baseline, one, four and twelve weeks to assess response to treatment.

Results: 21 patients (25%) carried the C allele of – 173 variant of the MIF gene. At 12 weeks, patients with the C variant had a statistically significant decrease in the pain dimension of the WOMAC compared to the G variant. Similar responses were not obtained at weeks one and four.

Conclusion: A specific polymorphism in the MIF gene appears to be associated with a poor response to intra-articular knee injections. Further validation is required with larger sample sizes to assess the impact of prospectively genotyping for this variant prior to knee injections.


Rajiv Gandhi Mark Takahashi Holly Smith Randy Rizek Nizar N Mahomed

Purpose: Obesity is known to be a risk factor for the incidence and progression of prevalent osteoarthritis (OA). The relationship is traditionally believed to be a mechanical effect on weight bearing joints such as the hip and knee, however studies showing a relationship between body mass index (BMI) and OA of non-weight bearing joints, such as the hand, suggest another theory. They suggest that the relationship between obesity and joint degeneration may be a systemic metabolic effect whereby visceral and sub-cutaneous truncal white adipose tissue (WAT) secrete inflammatory mediators that directly influence the pathogenesis of OA. We asked what is the relationship between adiponectin, leptin, and the A/L ratio and patient reported pain in an end stage knee OA joint population.

Method: We collected demographic data, Short Form McGill Pain scores, WOMAC pain scores, and synovial fluid (SF) samples from 60 consecutive patients with severe knee OA at the time of joint replacement surgery. Synovial fluid samples were analyzed for leptin and adiponectin using specific ELISA. Non-parametric correlations and linear regression modeling were used to identify the relationship between the adipokines and pain levels.

Results: The correlations between the individual adipokines and the pain scales were consistently less than that for the corresponding adipokine ratio. The A/L ratio correlated moderately with the MPQ-SF, (r(58) = − 0.46, p < .01) and the WOMAC pain score, (r(58) = − 0.38, p > .01). Linear regression modeling demonstrated that the A/L ratio was a significant predictor of a greater level of pain on the MPQ-SF(p=0.03, Table 3) but not the WOMAC pain scale(p=0.77, Table 4). Models were adjusted for age, gender, BMI, and medical comorbidity.

Conclusion: In conclusion, a greater A/L ratio predicted lower knee OA pain as measured by the MPQ-SF, but not on the WOMAC pain scale. This finding was above that of the individual adipokine levels alone. Some authors have suggested that leptin may have a proin-flammatory role while adiponectin an anti-inflammatory role in synovial joint diseases. Further work to elucidate these pathways may present a target for novel therapeutics in knee OA.


Guy Raz Oleg Safir Paul Lee Oren Ben Lulu David J Backstein Allan Gross

Purpose: An Osteochondral defect in the knees of young active patients represents a challenge to the orthopedic surgeon. Early studies on allogenic cartilage transplantation showed this tissue to be immunologically privileged, showed fresh grafts to have hyaline cartilage, and surviving chondrocytes present several years after implantation.

Method: Since January 1978 until October 1995 we enrolled 72 patients in a prospective non-randomized study of fresh osteochondral allografts in our institute. Ten international patients which were lost to follow-up were excluded. The major indications for the procedure were: patients younger than 60 years of age having post-traumatic unipolar defects larger than three cm in diameter and one cm in depth.

Results: Sixty two patients, ages 11–57 (mean 28) were followed for 15–31 years (mean 20.4 years). The etiology for the osteochondral defect was traumatic injury to the knee in 41 patients (66%), Osteochondritis Dissecans in 15 patients (24%), and in six patients (10%) due to other pre-existing conditions. Twenty of the 62 grafts have failed, with five having graft removal and 15 converted to total knee replacement. Three patients died during the course of this study due to unrelated causes. The Kaplan-Meier survivorship analysis showed: 92%, 79%, 56%, and 49% graft survival at 10, 15, 20, and 25 years respectively, (median survival = 23 years). Patients with surviving grafts had good function, with a modified Hospital for Special Surgery score of an average 88 at 20 years or more following the allograft transplantation surgery.

Conclusion: Through this long term study the authors confirm the value of fresh osteochondral allografts as a long term solution for large articular defects in the knees of young patients. The improvement of patients’ outcome compared to the previous published results of our earlier studies could be attributed to improved surgical techniques and increasing expertise of the senior authors. We therefore recommend the use of fresh osteochondral allografts for treatment of large osteochondral defects in the distal femur of young and active patients.


Richard W McCalden Steven JM MacDonald Kory D Charron Robert B Bourne Douglas D Naudie

Purpose: The range of motion after TKA depends on many patient, surgical technique, and implant factors. Recently, high-flexion designs have been introduced as a means of ensuring or gaining flexion after TKA. We therefore evaluated factors affecting postoperative flexion to determine whether implant design influences long-term flexion.

Method: We prospectively collected data on patients receiving a primary Genesis II total knee replacement with a minimum of 1-year followup (mean, 5.4 years; range, 1–13 years). We recorded pre – and postoperative outcome measures, patient demographics, and implant design (cruciate retaining [CR, n = 160], posterior stabilized [PS, n = 1177], high-flex posterior stabilized [HF-PS, n = 197]).

Results: Backward stepwise linear regression modeling revealed the following factors that significantly affected postoperative flexion: preoperative flexion, gender, body mass index, and implant design. Independent of gender, body mass index, and preoperative flexion, patients who received a HF-PS and PS design implant resulted in 8° and 5° more flexion, respectively, than those who received a CR implant. Based on analysis examining pre-operative flexion categories, patients with low flexion preoperatively (< 100°) were more likely to gain flexion, whereas those with high flexion preoperatively (> 120°) were most likely to maintain or lose flexion postoperatively. Controlling for implant design, patients with high flexion preoperatively (> 120°) were more likely to gain flexion with the HF-PS design implant (HF-PS = 32.0%; PS = 15.1%; CR = 4.5%).

Conclusion: In summary, our data demonstrate postoperative range of motion after TKA is related to several factors, confirming the important role of the patient’s preoperative range of motion. In addition, our review suggests knee design and, in particular, the use of a so called “high-flexion” PS polyethylene design may be advantageous in maintaining or improving flexion postoperatively, especially in those patients with good pre-operative range of motion.


Pierre Ranger Alexandre Renaud Philippe Dahan Josee Delisle Eros De Oliveira Philippe Phan

Purpose: Knee dislocation, although very rare, remains a devastating injury with many complications because of the complex nature of this trauma. The best treatment for knee dislocation is yet to be determined. The purposes of the study were to describe our surgical method, to report our results and to compare them with those of other surgical reconstruction techniques for knee dislocation.

Method: Fifty-six (56) patients with knee dislocation underwent acute combined reparation and reconstruction using Ligament Advancement Reinforcement System (LARS) artificial ligament. Patients were divided in three different groups according to the follow-up period. Group 1 (G1) included patients with a follow-up between two and six months post-op, group 2 (G2) involved patients with a follow-up between six months and twenty-four (24) months and group 3 (G3) was composed of patients who had a follow-up between twenty-four (24) and ninety-one (91) months.

Results: There was a significant difference between G1 and G3 for the Lysholm score and for the posterior stability at 90o of flexion measured with the Telos.

Conclusion: The subjective and objective findings from our series are satisfactory and comparable to the results of other series of knee dislocations. Our findings suggest that with a follow-up at seven years, acute combined reparation and reconstruction with LARS ligaments is a valid alternative for the treatment of knee dislocation.


David J Backstein Dror Lakstein Mohammad Zarrabian Yona Kosashvili Yona Kosashvili Oleg Safir Allan E Gross

Purpose: Component malrotation is a recognized cause of post total knee arthroplasty (TKA) pain. The objective of this study was to evaluate the functional outcomes of TKA revision for component malrotation, and to compare it to revision surgeries for aseptic loosening as a control comparison group.

Method: Twenty four patients who had TKA revision due to component malrotation as the only objective abnormality were reviewed. Only patients with preoperative computerized tomography (CT) documentation of 3° or more malrotation of at least one of the components were included. Mean combined rotation was 6.8° (range, − 12 − 3) excessive internal rotation. Twenty four matched control patients had TKA revision due to aseptic loosening.

Results: Mean follow up was 37 months (range, 24–65). Mean interval from index surgery was 41 months (range, 24–65) for the study group and 98 months (range, 11–222) for the control group (p=0.0003). Preoperative Knee Society Score (KSS) improved by 49 points (range, 16–80) at 6 months postoperatively for the malrotation patients and by 39 (range, − 7–78) for the loosening patients (p=0.08). At last follow-up, KSS was 80 (range, 60–89) for the malrotation group and 75 (range, 26–90) for the loosening group (p=0.14).

Conclusion: We recommend the use of CT scans in evaluation of all patients with early painful TKA’s and no objective evidence of infection. When component malrotation is demonstrated, we believe the results of this study validate consideration of early revision.


Emil H Schemitsch Mohit Bhandari

Purpose: Failure to adequately recruit patients in orthopaedic trials has often led to early stopping and publication of research findings from smaller sample sizes than originally planned. The purpose of this study is to demonstrate the effect of sample size in a large, clinical trial by using SPRINT trial data to evaluate the results that would have been reported if the trial were stopped at various enrollments.

Method: The SPRINT trial evaluated reamed vs. unreamed nailing in 1226 tibia fractures. We analyzed the re-operation rates after various increments in sample size and compared the early results that would have been reported at smaller enrollments with those seen in the final, adequately powered study.

Results: In the final analysis of 1226 patients, there was a significant reduction in the risk of re-operation with reamed nails for closed fractures (35% reduction; p=0.02) and a trend towards an increased risk of re-operation for open fractures (23% increase; p=0.26). In stark contradiction, the results for the first 50 patients enrolled in the trial revealed a substantial increased risk for reamed nails in closed fractures (risk increase: 165%). It was not until enrollment reached 800 patients that the results reflected the final findings of an advantage for reamed nails. In open fractures, the trend favoring unreamed nails was not seen until 200 patients had been enrolled.

Conclusion: Our findings suggest that stopping the SPRINT trial early would have led to misleading estimates of the treatment effect between reamed and unreamed nails.


Brad Petrisor Mohit Bhandari Bauke W Kooistra Bernadette G Dijkman Sheila Sprague

Purpose: To investigate

if adding the prospect of co-authorship to a survey’s final paper would increase, and

if the sending modality (fax or email) would affect, the six-week response rate of an orthopaedic survey.

Method: We identified orthopaedic surgeons through the internet-based Orthopaedic Trauma Association member list. All surgeons received the same questionnaire. In a factorial randomized, controlled fashion, they were allocated

to receive or not receive an additional cover page promising co-authorship of the survey’s final paper if they filled in and returned the survey (an “academic incentive”), and

to receive their survey by fax or email.

Results: For 429 surveyed surgeons, six-week response rates were similar for surgeons in the incentive – and no-incentive groups (36.8% vs. 35.4%, respectively, p=0.39). Similarly, response rates did not significantly differ between emailed and faxed surgeons (32.9% vs. 39.9%, respectively, p=0.13). The mean time to response seemed shorter in the incentive-group than in the no-incentive group (p=0.058).

Conclusion: We cannot recommend promising co-authorship to increase the response rates of surveys to orthopaedic surgeons. Additionally, emailed and faxed surveys yielded statistically similar response rates, leaving the decision regarding what modality to employ to time and money constraints.


Theodore D Cooke Lisa Sheehy David Felson

Purpose: Coronal mal-alignment contributes to total knee arthroplasty (TKA) failure. The surgical aim is to place the implant at right angles to the load-bearing axis, restoring the femoral and tibial mechanical axes (MA) to neutral. Mal-alignment of greater than 3° is associated with a poor outcome and reduced longevity. Pre-operative decisions for alignment correction are often made using anatomical axis (AA) measurements taken from standing short knee radiographs. The aim of this study was to determine how well the AA predicts the MA in subjects with mild and severe varus and valgus deformities. Several different methods of calculating the AA were also compared for their ability to predict the MA.

Method: The database of full-length lower extremity radiographs from the Multicenter Osteoarthritis (MOST) Study was used to select images for this study. All of the subjects in the MOST either had knee OA or were at high risk for developing knee OA. 120 full-length digital radiographs were assigned, with 30 in each of four alignment groups (0° to 4.9°, and ≥ 5° of varus and 0.1° to 4.9°, and ≥ 5° of valgus). The MA and 5 measures of the AA (using progressively shorter shaft lengths) were obtained from each radiograph using Horizons Analysis Software, OAISYS Inc. The offsets between the MA and the different versions of the AA were calculated (with 95% confidence intervals) for the complete sample of 120 limbs and for each alignment group. Pearson correlations were also calculated (α = 0.05).

Results: The average offset between the MA and the AA for the entire dataset was 5.0°. In varus limbs the shortened shaft AA measurements increased the offset from 5.1° to 7.0°. The opposite occurred with valgus limbs (from 5.0° to 3.7°). The CI for the offsets increased from less than 3° for the full-length AA measurements to over 8.3° for the shortest AAs. While correlations between MA and AA for the whole dataset were high (0.88 to 1.00), correlations for individual groups were much lower, especially for the shortest AA (0.41 to 0.66).

Conclusion: Using short knee radiographs to estimate the MA has important limitations. The offsets obtained using the shorter AAs vary depending on type and degree of mal-alignment, and do not provide reliable predictions for the MA. Full-length films are needed to consistently define the alignment in order to ensure the best outcome from TKA.


Daniel Varin Andrew Speirs Daniel Benoit Melanie Beaulieu Mario Lamontagne Paul E Beaulé

Purpose: A functional centre of rotation (CoR) is often required in biomechanical analysis of the hip or as a landmark in computer guided surgery. It was previously shown that circumduction motions predict a CoR that is inferior and lateral to the geometric centre of the hip bearing surfaces. It is therefore necessary to establish the best method for determining the CoR to improve surgical planning. The objective of this study was to compare the predicted CoR from circumduction and star motions, and to compare these to the geometric centre of the joint.

Method: Eight cadaveric hips from four cadavers were tested. Prior to testing, CT scans of the cadavers were made from the iliac crest to the tibial plateau; the alpha angle for all hips was less than 50° so all hips were considered ‘normal’. Reflective marker arrays were rigidly mounted on the femoral diaphysis and iliac spine using 4mm Steinman pins. A five-camera Vicon system (Oxford, UK) was used to track the motions of the arrays during manipulation of the lower limb. To determine the functional hip centre, trials consisting of five cycles each of circumduction, flexion-extension and abduction-adduction were performed on each lower limb; three trials of each motion were performed. The range of motion was approximately 45° in the coronal and sagittal planes. For the ‘star’ motion, the flexion-extension and abduction-adduction trial data were combined. Following the trials the hip was dissected to expose the articular surfaces of the femoral head and acetabulum. These surfaces were traced using a pointer equipped with reflective markers to determine the geometric centre. To calculate the functional centre, the 3D coordinates of the markers were used to construct a local-to-global 3D transform for each frame throughout the trial. The geometric centre was calculated using a least-squares sphere fit (Gauss-Newton) of the trace data, calculated in the respective local coordinate systems. The coordinates of the functional centres were then transformed to an anatomic coordinate system, using the geometric centre as the origin. All calculations were performed using Matlab (Mathworks, Inc, MA, USA). A t-test was performed in each anatomic direction to detect differences in CoR predicted by the two motions.

Results: Both the circumduction and star motions resulted in a similar CoR. Differences were 0.41±2.25mm in the anterior-posterior direction; 0.09±0.72mm in the superior-inferior direction; and 0.21±0.82mm in the medial-lateral direction, none of which were significant (p> 0.5). The overall mean distance between the CoR predicted by the two motions was 2.0±1.3mm. The functional centre was also found to be lateral and inferior to the geometric centre, and was consistent for each motion. Results for the acetabulum showed similar trends.

Conclusion: This study has shown that circumduction and star motions are equivalent in predicting the hip functional CoR; differences were small compared to the dimensions involved in studies such as gait analyses. However, both motions predicted a CoR that was inferior and lateral to the spherical centre of the femoral head, suggesting that the hip does not act as a true ball-and-socket joint with congruent spherical bearing surfaces. This may have important consequences in studies at the scale of the hip joint, especially for pathological conditions such as femoroacetabular impingement.


John J Murnaghan Karen Fairley Ramez Hanna

Purpose: To determine the wound healing rate, perioperative mortality and ambulatory status of patients following knee disarticulation.

Method: Retrospective review of all cases performed by one surgeon at tertiary center. Charts reviewed for demographic data, surgical and follow-up data. Ambulatory status preop and postop graded after Volpicelli et al. Descriptive statistics applied.

Results: 34 knee disarticulations in 28 patients. 3 perioperative deaths (11%). Report on 31 procedures in 25 patients with mean follow-up of 7 months. 20 males, 5 females. Mean age 73 (55–92). PVD 21/25. Diabetes Mellitus 13/25 (52%). Chronic infection 2, Scleroderma 1 and squamous cell carcinoma 1. Primary wound healing 25 (81%). Delayed healing 6 (19%). Reoperation 1. Revision of amputation 0. Mean ambulatory status preop 2.5/6. Mean ambulatory status postop 1.8/6.

Conclusion: Knee disarticulation is a reliable surgical procedure with 81% primary healing in high risk population. Knee disarticulation should be considered as an option to above knee amputation for patients with PVD and complications of diabetes


Nicole Simunovic Mohit Bhandari Bauke W Kooistra Bernadette Dijkman

Purpose: Estimating recruitment for clinical trials is vital to ensuring the feasibility of larger multi-centre trials. We compared estimates of potential recruitment from a prospective eight-week screening study and a retrospective chart review across sites participating in three fracture management trials.

Method: During the planning phase of two multi-centre, randomized controlled trials regarding the operative treatment of hip (two studies) and tibial shaft (one study) fractures, 74 clinical sites provided estimates of the annual recruitment rate both retrospectively (based on chart reviews) and prospectively. The prospective estimate was generated by screening all incoming patients for eligibility in the concerning trial, without actually enrolling any patient, for eight weeks. These prospective and retrospective estimates were correlated with each other (for 74 sites) and with actual one-year recruitment rates in the definitive trial (for nine sites).

Results: On average, a centre’s prospective estimate was only slightly lower than its retrospective estimate (3.1 patient-difference, p=0.64). Both predictions were substantial overestimations of recruitment in the definitive trial; only 31% (95% confidence interval: 28%–35%) of retrospectively estimated patients and 34% (95% confidence interval: 30%–37%) of prospectively estimated patients were recruited in the definitive trials (p< 0.001 and p=0.001 for both overestimations, respectively). The overall costs of conducting retrospective chart reviews and prospective screening studies in 65 sites were $68,107 ($CAN) and $153,725 ($CAN), respectively.

Conclusion: Compared to relatively simple and inexpensive chart reviews, prospectively screening for eligible patients at clinical sites did not result in more accurate predictions of accrual in large randomized controlled trials.


Rajiv Gandhi Yoga R Rampersaud Nizar N Mahomed Pamela Hudak Christian Veillette Khalid Syed Steve Lewis J Roderick Davey

Purpose: Factors influencing patient willingness to undergo elective surgery are poorly understood.

Method: We prospectively evaluated patient concerns prior to surgical consultation for elective spinal, hip, knee, shoulder/elbow (S/E), or foot/ankle (F/A) conditions. Patients were surveyed for demographic data, SF 36 quality of life (QOL) scores and asked to report their greatest concern about considering surgery for their condition, as well as their willingness to undergo surgery if it was offered to them by their treating surgeon.

Results: In our prospective cohort of 743 patients, 364 (51%) were male and 293 (39 %) were evaluated for a spine condition, 74 (10 %) hip, 192 (26 %) knee, 69 (9 %) S/E, and 115 (16 %) F/A. Mean QOL scores were similar for patients across specialities. The top three greatest concerns for undergoing elective musculoskeletal surgery were potential complications (20%), effectiveness (15%) and recovery time (15%) of surgery. When categorized by specialty, concern of surgical complications was the most prevalent in spine (23%) and F/A patients (30%). However, patients were most commonly unsure of risks associated with their respective subspecialty surgery (spine – 56%; hip – 53%; knee – 44%; S/E – 48% and F/A – 33%). The majority of hip patients (89%) perceived a high success rate for hip surgery, while 65% of spine patients where unsure of the success of spine surgery. Patient willingness to undergo surgery was greatest for hip (84%), knee (78%), and S/E (82%) surgery and least for spine (68%) and F/A surgery (74%).

Conclusion: Although patient willingness to consider surgery is clearly a multifactorial decision, patient perception of surgical risk or success prior to surgical consultation are significant factors.


David W Walmsley Christopher Peskun James P Waddell Emil H Schemitsch

Purpose: There is growing support in the medical literature that patient outcomes are adversely affected by physician fatigue in operator-dependent cognitive and technical tasks. The recent increase in total joint arthroplasty case load has resulted in longer operative days and increased surgeon fatigue. The purpose of this study was to determine if time of day predicts perioperative outcomes and complications in total hip and knee arthroplasty surgery.

Method: The records of all primary Total Hip Arthroplasty (THA) and Total Knee Arthroplasty (TKA) surgery performed for primary osteoarthritis, during 2007 at one large university hospital, were retrospectively reviewed. Complete demographic data (age, gender, Body Mass Index), start time of surgery, intraoperative complications, duration of surgery, radiographic component alignment, and functional outcome scores (SF-12 and WOMAC) for 341 THA and 292 TKA patients were collected and analyzed using linear and nonparametric rank correlation statistics. Data was corrected for gender, body mass index (BMI), surgeon, and post-call operating days.

Results: In the THA cohort, a later start time of surgery was significantly related to duration of surgery (p=0.0013). In addition, there was a trend towards significance for intraoperative femur fracture (p=0.0542) later in the day. Postoperative complications, component alignment, and functional outcome scores were not significantly affected by start time of surgery. There were no significant findings for any of the intraoperative or postoperative outcomes in the TKA cohort.

Conclusion: This study demonstrates that duration of surgery and the incidence of intraoperative complications for THA may increase as the start time of surgery becomes later in the day. These findings should be taken into consideration when planning operative days involving THA.


Paul E Beaulé Stephane Poitras Geoffrey F Dervin

Purpose: The Quality of Recovery-40 questionnaire (QoR-40) has been developed, validated and extensively used to assess the quality of life of patients following major surgery. It is composed of 40 questions answered by the patient and organized into six dimensions: emotional state, physical comfort, psychological support, physical independence, pain, and global score. However, this questionnaire has not been validated in an orthopaedic population. The objective of the study was to assess the psychometric properties of the QoR-40 in a population of patients undergoing total knee or hip arthroplasty.

Method: Sixty seven patients undergoing total knee arthroplasty and 65 patients undergoing total hip arthroplasty were recruited. Patients were assessed with the QoR-40 and the SF-12, a validated generic quality of life questionnaire, at the following seven times: three and one week pre-operative; one, two and three days post-operative (short-term); one and three months post-operative (long-term). The following psychometric properties of the QoR-40 were assessed: reliability between three and one week pre-operative using intra-class correlation coefficients (ICC), construct validity with the SF-12 using Pearson product moment correlations, responsiveness to change using effect sizes, floor and ceiling effects, and predictive validity of short-term QoR-40 scores of long-term SF-12 scores.

Results: All dimensions and global scores of the QoR-40 appeared reliable, with ICCs’ ranging from 0.75 to 0.84. For construct validity, physical dimension scores of the QoR-40 (physical comfort, physical independence, pain) were weakly or not significantly related to the physical component scale of the SF-12 (−0.09 to 0.34), except for long-term where the correlations were moderate (0.35 to 0.62). The emotional state score of the QoR-40 was moderately to substantially related to the mental component scale of the SF-12 for all periods (0.40 to 0.78). Effect sizes were higher for the QoR-40 when compared to the SF-12 in the intervals of the first month, while they were higher for the SF-12 in the intervals above one month. The QoR-40 demonstrated ceiling effects for the physical independence dimension pre-operatively and three months post-operatively, and for all periods for the psychological support dimension. As for predictive validity, short-term post-operative QoR-40 scores were weakly or not significantly predictive of long-term postoperative SF-12 scores (0.01 to 0.41).

Conclusion: The QoR-40 appears to be a reliable tool assessing a quality of life construct different from the SF-12 and more responsive to change during the short-term follow-up to surgery. The QoR-40 could be used to assess short-term quality of life following surgery. The QoR-40 should not be used to predict long-term quality of life. To further improve the tool, the psychological support dimension of the QoR-40 should be reconceptualized because of ceiling effects.


Pamela Hudak Shannon Clark Geoffrey Raymond

Purpose: Only 30% or less of patients who see an orthopaedic surgeon are surgical candidates. Thus, orthopaedic surgeons’ role in the management of musculoskeletal conditions is wider than surgery and, accordingly, their treatment recommendations include much more than surgery as well. This paper examines the delivery of recommendations not for surgery (NFS) in routine orthopaedic surgery consultations.

Method: Audio-recordings of routine consultations between 121 patients and 14 surgeons from two tertiary care hospitals in a large Canadian city were collected and analyzed using Conversation Analysis, a rigorous, empirical approach to the study of interaction which seeks to reveal sequential structures and patterns in naturally occurring talk, and to explain why these patterns are important.

Results: In contrast to recommendations for surgery, which tend to be delivered fairly quickly and straightforwardly, the delivery of NFS recommendations tends to be elaborate and complex. Orthopaedic surgeons recurrently utilize a cluster of interactional devices in the lead-up to NFS recommendations, including:

projecting turns – turns which indicate that the surgeon will produce an extended turn;

parenthetical remarks – self-qualifying remarks inserted into a turn underway;

‘brightsides’ – comments which emphasize something positive about the patient’s case or condition;

syllogisms – turns which allow patients to make logical deductions about the nature of the recommendation to come; and

usual case or general course descriptions.

Additionally, even though surgery is not being recommended, NFS recommendations are positioned in relation to surgery. Surgeons use this cluster of devices to manage a range of competing demands, for example, showing that they are taking the patient’s problem seriously, being attentive to the patient’s treatment expectations, explaining the rationale for the recommendation, and positioning the recommendation not for surgery in relation to surgery – e.g., explaining why surgery is not being recommended now, and/or the conditions under which surgery would be offered in the future. Through this cluster of devices, surgeons forecast the nature of the recommendation to come, lay bare the evidential basis for the recommendation and work to obtain patients’ subsequent acceptance of the recommendation. The cluster, as a whole, constitutes a persuasive argument for the upcoming recommendation.

Conclusion: Delivering not for surgery recommendations is a complex task, one which surgeons handle skillfully using several interactional devices. Surgeons treat these recommendations as requiring a persuasive case. An appreciation for the complexities and constraints of delivering NFS recommendations can be used to inform clinical practice and the teaching of communication skills.


Hans Hundt Jennifer Fleming Abdel Lawendy Kevin Gurr Stewart I Bailey David Sanders Greg McGarr Relka Bihari Christopher S Bailey

Purpose: Recent studies have examined the systemic inflammation that occurs following spinal cord injury (SCI) (Gris et al. 2008). It is believed that this systemic inflammation plays a role in the respiratory, renal and hepatic morbidity of SCI patients, ultimately contributing to mortality post-injury. Evidence of this inflammatory response has been shown as early as two hours post SCI (Gris et al. 2008) Intravital microscopy is a powerful tool for assessing inflammation acutely and in ‘real-time’ (Brock et al. 1999). This tool would be useful for demonstrating the acuteness of a systemic inflammatory response post-SCI, and for assessing the degree of inflammation to different severities of SCI. The liver has been shown to play a particularly important role in the initiation and progression of the early systemic inflammatory response to spinal cord injury (SCI), therefore the purpose was to evaluate hepatic inflammation immediately after SCI. We hypothesized that SCI would cause immediate leukocyte recruitment and that the magnitude of inflammation would increase with increasing severity of cord injury.

Method: Male Wistar rats (200–225g) were randomly assigned to one of the following groups: uninjured, trauma-injured (laminectomy and no cord injury), cord compressed or cord transected. Spinal cord-injured rats were anesthetized by isoflurane, a dorsal laminectomy was performed, and the 4th thoracic spinal segment was injured by a moderately severe clip-compression injury or by a severe complete cord transection injury. Uninjured rats and trauma-injured rats served as controls. At 0.5 and 1.5 h after SCI rats had the left lobe of their livers externalized and visualized using intravital video microscopy.

Results: At 0.5 hours the total number of leukocytes per post-sinusoidal venule was significantly increased after cord compression and cord transection compared to that in uninjured and trauma-injured rats (P< 0.05). Of these leukocytes significantly more were either adherent or rolling along venule walls compared to uninjured and trauma-injured rats (P< 0.05). Of the rolling leukocytes 2–fold more were observed after cord transection compared to cord compression. At 1.5 h the total number of leukocytes per post-sinusoidal venule and the number of adherent leukocytes was significantly increased only after cord transection.

Conclusion: Injury to the spinal cord but not trauma alone causes immediate leukocyte recruitment to the liver within 0.5 h after injury. Also, leukocyte recruitment increases with increasing severity of injury. This is the first study to use intravital microscopy to visualize systemic inflammation in the liver following SCI.


Seyed-Parsa Hojjat Cari M Whyne

Purpose: To examine the effect of image resolution and structural model on quantifying architectural differences between healthy and metastatically involved vertebrae.

Method: Lumbar vertebrae of healthy(n=6) and meta-statically involved(n=6) rnu/rnu rats were utilized. Osteolytic vertebral metastases were developed via intracardiac injection of human MT1 breast cancer cells. μCT images of the vertebrae were acquired ex vivo at 14μ isotropic spatial resolution. The whole vertebrae were segmented using an automated atlas based demons deformable registration followed by level set curvature evolutions. A subsequent iteration of level set was used to yield a segmentation of the trabecular centrum. The individual trabecular network was further segmented using intensity based thresholding. Architectural parameters were computed from the segmented μCT images: Cortical Bone Volume(CBV), Trabecular Bone Volume(TBV), Trabecular Bone Surface Area and the degree of anisotropy based on Mean Intercept Length(MIL). From this, trabecular Thickness(TbTh), Trabecular Number(TbN) and Trabecular Separation(TbS) were calculated using the Parfitt Model (Parfitt, Bone & Mineral. 1987). TbTh was also calculated separately using the Hilderbrand model (Hilderbrand, J of Microscopy 1997). The degree of anisotropy was determined via Mean Intercept Length (MIL) measured utilizing a binary shift/subtraction approach. The measures of TbTh and MIL were compared for each image at 8.725(high), 17.45(medium) and 34.9(low) μm3 isotropic spatial resolutions.

Results: Parfitt’s plate model showed a significant decrease in TBV, TbN and CBV and a significant increase in TbS in the metastatic vertebrae in comparison to the healthy group at the highest resolution. In both Hilderbrand’s and Parfitt’s models at the highest resolution there was no significant difference in TbTh between the healthy and metastatic groups. In both models, TbTh and TbS values rose while TBV and TbN decreased as the resolution was lowered. Significant reductions were observed only in TbTh between the healthy and metastatic vertebrae at the medium and low resolutions. In all cases, the Hildebrand model yielded lower values of TbTh than the Parfitt model. However, achieving robust automated results using the Hildebrand method was limited in the final stage of the segmentation due to sensitivity to small islands of bone. Structural anisotropy remained consistent in all groups at all resolutions, with ~3x greater MIL in the superior/inferior direction. The degree of anisotropy was, however, consistent in both groups suggesting that the metastatic destruction does not have any directional preference.

Conclusion: The automated use of Parfitt’s plate model along with the MIL method can be used to yield quantitative analyses demonstrating differences in vertebral microstructure due to metastatic involvement. However the sensitivity of these architectural parameters to resolution motivates the need for high resolution scanning in future preclinical applications.


Sheila Sprague Gregory Della Rocca Sonia Dosanjh Emil H Schemitsch Mohit Bhandari

Purpose: In recent years, there has been an increased appreciation of the importance of intimate partner violence (IPV), which is also known as domestic violence, spouse abuse, and battering, as a serious public health problem. Domestic violence is the most common cause of nonfatal injury to women in North America. As providers of musculoskeletal care and first-contact health care practitioners for many patients, orthopaedic surgeons should be knowledgeable regarding screening and possible interventions for IPV victims. The Canadian Orthopaedic Association and the American Academy of Orthopaedic Surgeons have both prepared explicit statements that orthopaedic surgeons should play a role in the screening and appropriate identification of victims of IPV. We aimed to identify the knowledge, attitudes, and beliefs about IPV among orthopaedic surgeons who are members of the Orthopaedic Trauma Association.

Method: We surveyed members of the Orthopaedic Trauma Association to identify attitudes toward IPV by posting a survey on the Orthopaedic Trauma Association website for its membership to complete. The survey consisted of three sections:

the general attitude of the orthopaedic surgeon toward intimate partner violence,

the attitude of the orthopaedic surgeon toward victims and batterers, and

the clinical relevance of intimate partner violence in orthopaedic surgery.

Results: One-hundred-and-fifty-three orthopaedic surgeons responded. The majority of the respondents were male (99%) with practices in North America (96%). Surgeons underestimated the prevalence of IPV in their practices and communities and manifested several key misconceptions:

victims must be getting something out of the abusive relationships (16%);

some women have personalities that cause the abuse (20%); and

the battering would stop if the batterer quite abusing alcohol (40%).

In the past year, approximately half of the surgeons (50.8%) acknowledged identification of a victim of IPV; however, only 4.0% of respondents currently screened for IPV among female patients with injuries. Surgeons expressed concerns about lack of knowledge in the management of abused women (30%) Guidelines for the detection and management of IPV were uncommon in most surgeons’ practices (7.8%).

Conclusion: There is a strong rationale for addressing IPV as an issue that is relevant to the field of orthopaedic surgery just as it has been shown to be relevant to primary care, emergency medicine, and obstetrics and gynecology. Our study found that orthopaedic surgeons underestimated the prevalence of IPV in their practices, held multiple misperceptions about IPV, and demonstrated discomfort in identifying and treating IPV. Targeted educational programs on IPV are needed for surgeons who routinely care for injured women.


Fackson Mwale Guoying Yao Alain Petit John Antoniou

Purpose: Mesenchymal stem cells (MSCs) from osteoarthritic (OA) patients are not well characterized and little is known of how they are regulated. Recent evidence indicates that a major drawback of current cartilage and intervertebral disc (IVD) tissue engineering is that human MSCs from OA patients express type X collagen (COL10), a marker of late-stage chondrocyte hypertrophy (associated with endochondral ossification). However, the intracellular pathways for transducing signals that regulate hypertrophy in MSCs remain unclear. In chondrocytes, this pathway is mediated by mitogen activated protein kinase (MAPK) p38. The aim of this study was to determine the phosphorylation levels of ERK/p38 MAPK signaling molecules in MSCs from OA patients compared to those from normal patients.

Method: MSCs were obtained from aspirates from the intramedullary canal of donors (60–80 years of age) undergoing total hip replacement for OA. Cells were cultured in DMEM high glucose supplemented with 10% fetal bovine serum, 100 U/ml penicillin, and 100 μg/ml streptomycin for 2–3 passages. Cells were then lysed and proteins were separated on 10% acrylamide gels and transferred to nitrocellulose membranes. Protein expression was determined by Western blot using specific antibodies directed against type X collagen, ERK, phosphorylated-ERK, p38, phosphorylated-p38, JNK, phosphorylated-JNK, AKT, and phosphorylated-AKT. GAPDH was used as a housekeeping gene. Proteins were detected using the West Pico Chemiluminescence substrates and analyzed using the Bio-Rad VersaDoc equipped with a cooled CCD 12 bit camera. Normal mesenchymal stem cells from a 22 years old woman were purchased from Lonza (Switzerland).

Results: Results show that the expression of COL10 was markedly increased in MSCs of OA patients compared to control patient. Results also shows that the phosphorylation of all the signal transduction proteins studied was induced in MSCs of patients with OA. Indeed, the phosphorylation of ERK (3.4±0.9 times the control), p38 (1.7±0.3 times the control), JNK (5.40±1.14 times the control), and AKT (4.3±0.8 times the control) was higher in MSCs of OA patients compared to control normal patients.

Conclusion: In the normal donor, MSCs continue to exhibit their in situ behavior in that they expressed very little or no COL10. This may relate to the fact that normal MSCs being multipotent in nature like to maintain an undifferentiated state. In contrast, MSCs from OA patients expressed COL10: this suggests that they are in a situation were they can be preprogrammed not only to replace the degraded articular cartilage but also the damaged subchondral bone. Since the phosphorylation of ERK/p38 MAPK signaling molecules is also lower in normal MSCs, our results also suggest that this signaling pathway is implicated in the control of COL10 expression. This finding is of great importance for the understanding of COL10 regulation in general and may lead to important advances in the comprehension of COL10 related diseases.


Margarete K Akens Emily Won Lisa Wise-Milestone Brian C Wilson Albert JM Yee Cari M Whyne

Purpose: Bony metastases in vertebrae secondary to breast cancer can result in osteolysis and an increase in skeletal related events. Bisphosphonates (BP) are the current standard of care for breast cancer patients with skeletal disease. Photodynamic therapy (PDT) is a non-radiative treatment, which has been successfully applied to various malignancies and shown to successfully ablate vertebral human breast cancer (MT1) metastases in a murine model. Previous in-vitro study has shown that pre-treatment of MT-1 cells with the BP zoledronic acid (Zometa®) renders them more susceptible to PDT. The aim of this study was to evaluate the influence of pre-treatment with BPs on the effect of PDT treatment on tumour ablation in metastatically involved vertebrae in vivo.

Method: Metastases were induced in fourteen 5–6 weeks old female athymic rats (Hsd:RH-Foxn1rnu) by intra-cardiac injection of 2x10^6 MT-1 cells. Four groups were formed:

control, no treatment;

BP only;

PDT only;

BP and PDT combined.

Seven days after MT-1 injection 60 μg/kg of zoledronic acid was injected. PDT treatment was administered on day 14 using the photosensitizer BPD-MA (1.0 mg/kg; Visudyne). Fifteen minutes later, laser-light (690nm; 75J) was administered to the lumbar vertebrae. The rats were euthanized 7 days after PDT treatment. A total of 45 vertebrae were evaluated using a histomorphometric program (GENIE™, Aperio) to assess tumour burden. Statistical analyses were performed using a one-way ANOVA with a Tukey post hoc test. A p-value p< .05 was considered to be statistically significant..

Results: The total The total tumour burden within vertebrae of rats pre-treated with BP and/or PDT was significantly lower compared to the control rats (p< .001). In addition, the PDT alone treated group demonstrated significantly less tumour burden than the combined BP+PDT group. In the control and BP-only groups, large tumours were found to include regions of necrosis. The PDT treatment groups (PDT and BP+PDT) exhibited areas of necrosis throughout the entire vertebral bodies with adjacent formation of granulation tissue.

Conclusion: BP, PDT and combined BP+PDT treatments resulted in a lower overall tumour burden at day 21 post MT-1 cell injection compared to control rats. A surprising increased level of tumour burden was found in comparing the combined treatment group to the PDT-only group. These findings are in contrast to previous in-vitro results, where the pre-treatment with BPs made the cells more susceptible to PDT. Pre-treatment with BP affects both the bone and tumour cells, and as such may induce different cellular pathways in response to PDT treatment. However, the ability of PDT applied at day 14 to cause a similar reduction in tumour burden compared to BP treatment at day 7, suggests its ability to rapidly and effectively ablate the tumour within the bone, even in the presence of BP.


Fackson Mwale Laura M Epure Tomoaki Yoshikawa Aseem Hemmad Megan Bokar Koichi Masuda Peter J Roughley John Antoniou

Purpose: Intervertebral disc (IVD) degeneration is associated with proteolytic degradation of proteoglycan aggregates present within the extracellular matrix of the disc. Link-N peptide is the N-terminal peptide of link protein, which stabilizes the proteoglycan aggregates. It is generated in vivo by proteolytic degradation during tissue turnover. We have previously shown that this peptide can stimulate the synthesis of proteoglycans and collagens by IVD cells in vitro. However, to date, there have been no reports on the effect of Link-N on the IVD in vivo. The purpose of the present study was to determine the effect of intradiscally administration of Link-N peptide on disc cell survival and extracellular matrix synthesis using a rabbit annular needle puncture model of IVD degeneration.

Method: Twelve New Zealand white rabbits (~3.5 kg; 5–6 months old) received an annular puncture with an 18-gauge needle on 2 non-contiguous discs (L2–L3 and L4–L5). The disc (L3–L4) between the punctured discs and that above (L5–L6) was left intact as internal controls. Two weeks after the initial puncture, the anterior surfaces of the previously punctured discs (L2–L3 and L4–L5) were injected with either saline (10 μl/disc) or Link-N (100 μg in 10μl saline/disc) into the center of the NP. Disc height was radiographically monitored biweekly. After 12 weeks post-injection, all the rabbits were euthanized and the IVDs from both experimental groups were removed from each lumbar spine for biochemical analysis. The nucleus pulposus (NP) was separated from the annulus fibrosus (AF), the specimens weighed (wet weight), the content of DNA measured using PicoGreen, and the total contents of sulfated glycosaminoglycans (GAG) measured by the 1,9-dimethylmethylene blue (DMMB) assay.

Results: Following needle puncture that initiates disc degeneration, the disc height index (DHI) decreased by about 25%. By 6 weeks after Link-N injection, the mean percent DHI of injected discs in the Link-N group was higher than in the saline group. This difference in mean percent DHI was maintained during the rest of the follow-up. Puncturing the IVD also led to a decrease in proteoglycan content in both the NP and the AF in saline-treated discs. Treatment with Link-N stimulated proteoglycan synthesis (GAG) in both the NP and AF by about 20%. Link-N did not cause an increase in the DNA content of the discs.

Conclusion: Results of the present study show that Link-N can stimulate proteoglycan production in vivo when administered to degenerate disc. This stimulation occurs in both the NP and AF of the disc and in the absence of any effect on cell division. The changes observed with Link-N on proteoglycan synthesis are similar to those reported after injection of osteogenic protein-1 (OP-1) Thus, Link-N appears to be equally effective at stimulating repair of the IVD in vivo. One major advantage of Link-N over OP-1 for therapeutic use is the large saving in cost, Link-N being about 400 times cheaper than OP-1.


Randy DC Barley Keith M Bagnall Nadr M Jomha

Purpose: Traditionally, chondrocyte growth and characterization studies have been conducted using non-physiologic, normoxic, monolayer culture systems that have the major drawback of dedifferentiation. Recently, however, the use of novel 3D culture systems, cytokine supplementation or hypoxic culturing techniques have shown that chondrocyte dedifferentiation can be greatly reduced. Unfortunately, to date, no single culture technique has been identified that completely prevents the dedifferentiation-related changes in ECM gene expression. We hypothesized that combining a high density culture condition with an hypoxic environment would improve chondrocyte phenotype retention as determined by gene expression and protein production when compared to current standard culture conditions.

Method: Freshly isolated normal human articular chondrocytes were maintained in three culture conditions:

conventional monolayer culture,

high density monolayer culture (HDMC) and

embedded in alginate and compared to freshly isolated positive controls (FIC) and fibroblasts as negative controls.

The conventional monolayer cultures were harvested at confluence while HDMC and alginate-embedded chondrocytes (AEC) were maintained in culture for 8 weeks. Parallel experiments were conducted under normoxic (21% O2) and hypoxic (5% O2) conditions for all three experimental groups. Chondrocytes were harvested, RNA was extracted and quantitative RT-PCR was performed using primers for collagens (I, II, VI, IX and XI), aggrecan, SOX-9, HIF-1, 3 different integrins and GAPDH. In addition, collagen and GAG content was quantified when possible using Sircol and Blyscan assays respectively.

Results: HDMC cultures in hypoxic conditions showed a 2.5 fold increase in wet weight, a 6.9 fold increase in GAG content and a 1.3 fold increase in collagen content relative to normoxic HDMCs. With respect to gene expression levels, only the HDMCs in hypoxic culture conditions yielded mRNA expression levels of collagen II, IX, XI, aggrecan, HIF-1, SOX-9 and one Integrin that were consistent with the levels seen in freshly isolated chondrocytes (positive control). Importantly, HDMC culture in hypoxic conditions also yielded the lowest levels of collagen I of any experimental condition.

Conclusion: This research demonstrated that high density monolayer culture in hypoxic conditions prevented the severe loss of chondrocyte phenotype typically associated with conventional monolayer culture. Cells cultured in these conditions demonstrated gene expression levels similar to those seen in FICs, which are superior to those seen following conventional culture conditions such as the use of alginate beads. These culture conditions provide a novel opportunity to maintain chondrocyte phenotype over a prolonged period of time while generating extracellular matrix that may be beneficial for treatment of full thickness cartilage defects.


Sonia Rampersad Alain Petit Guoying Yao Amélie St-Georges-Robillard Juan-Carlos Ruiz Michel R Wertheimer John Antoniou Fackson Mwale

Purpose: Several studies have been directed toward using mesenchymal stem cells (MSCs) from osteoarthritic (OA) patients for cartilage or disc repair because these patients are the ones that will require a source of autologous stem cells if biological repair of tissue lesions is to be a therapeutic option. A major drawback of current cartilage and intervertebral disc tissue engineering repair is that these cells rapidly express type X collagen, a marker of late stage chondrocyte hyperthrophy implicated in endochondral ossification. However, a novel plasma-polymerized thin film material, named nitrogen-rich plasma-polymerized ethylene (PPE:N), is able to inhibit type X collagen expression in committed MSCs. The specific aim of this study was to determine if the suppression of type X collagen by PPE:N is maintained when MSCs are transferred to pellet cultures in chondrogenic defined media.

Method: MSCs were obtained from aspirates from the intramedullary canal of donors undergoing total hip replacement for OA using a protocol approved by the Research Ethics Committee of our institution. Cells were then expanded for 2–3 passages in DMEM high glucose supplemented with 10% fetal bovine serum, 100 U/ml penicillin, and 100 μg/ml streptomycin, and finally cultured on polystyrene (PS) cell culture dishes or PPE: N surfaces for 3 and 7 days. Cells were transferred for 3 additional days in a chondrogenic serum free media (DMEM high glucose supplemented with 2 mM L-glutamine, 20 mM HEPES, 45 mM NaHCO3, 100 U/ml penicillin, 100 μg/ml streptomycin, 1 mg/ml bovine serum albumin, 5 μg/ml insulin, 50 μg/ml ascorbic acid, 5 ng/ ml sodium selenite, 5 μg/ml transferrin) in pellet culture or on PS cell culture dishes. Cells were then lysed and proteins were separated on 4–20% acrylamide gels and transferred to nitrocellulose membranes. Type X collagen was detected by Western blot; GAPDH expression was used as an internal control for protein loading.

Results: Results showed that type X collagen protein was expressed in MSCs from OA patients cultured on polystyrene but was suppressed when cultured on PPE: N. Since defined chondrogenic medium are commonly used in pellet culture to promote in vitro chondrogenesis, we then investigated the effect of transferring cells pre-cultured on PPE:N into pellet culture on type X collagen expression. However, the decreased type X collagen expression was not maintained in these conditions and that the expression returned to control values. The decreased type X collagen expression was maintained when the cells were cultured on PS cell culture dishes.

Conclusion: The use of MSCs is promising for tissue engineering of cartilage and intervertebral disc. The present study confirmed the potential of PPE:N surfaces in suppressing type X collagen expression in MSCs from OA patients. However, when MSCs stem cells are transferred to pellet cultures, type X collagen is rapidly re-expressed suggesting that pellet cultures may not be suitable for chondrogenesis of MSCs from OA patients.


Angela Melnyk Stephen P Kingwell Qingan Zhu Jason Chak Marcel F Dvorak Thomas R Oxland

Purpose: At present there is no reported, valid and reproducible model of degenerative spondylolisthesis for biomechanical testing of spinal implants. The purpose of this study was to create a single functional spinal unit (FSU) model that could demonstrate anterolisthesis consistent with low grade degenerative spondylolisthesis under physiologic shear loads.

Method: Eight fresh-frozen human cadaveric, lumbar FSU’s were potted and secured in a custom jig for pure shear testing. The cranial segment was loaded from – 50N (posterior) to 250N (anterior) over three cycles for each of five test conditions with a 300N preload. Test conditions addressed known restraints to shear translation and were performed in the same order for all specimens, and included: intact, facet capsulectomy and bilateral two mm facet gap, bilateral four mm facet gap, nucleotomy, and annular release. Three-dimensional motion was recorded using an optoelectronic camera system.

Results: Mean anterior translation at 250N for the five test conditions was 0.7 mm (95% confidence interval 0.4 to 0.9), 1.2 mm (0.9 to 1.6), 1.5 mm (1.1 to 2.0), 1.9 mm (1.4 to 2.4) and 3.1 mm (2.2 to 4.0). The mean maximum anterior translation was significantly different for each test condition with two exceptions. The four mm facet gap did not result in a significantly different maximum anterior translation compared to the two mm facet gap or the nucleotomy. There were no differences in off-axis motion (lateral or superior-inferior translation, flexion-extension, axial rotation, lateral bending) between the five test conditions.

Conclusion: Anterior translation consistent with low grade degenerative spondylolisthesis was repeatedly demonstrated under physiologic shear loads using this model. All sequential destabilizations preserved anatomy critical for the application of pedicle screw constructs, interbody devices and interspinous spacers. As such, this model is appropriate for biomechanical testing of implants currently used in the treatment of low grade degenerative spondylolisthesis.


Fackson Mwale Alain Petit Guoying Yao John Antoniou

Purpose: A major drawback of current cartilage and intervertebral disc tissue engineering is that human mesenchymal stem cells (MSCs) from osteoarthritis (OA) patients express type X collagen (COL10), a marker of late-stage chondrocyte hypertrophy (associated with endochondral ossification). Parathyroid hormone (PTH) and parathyroid hormone-related peptide (PTHrP) regulate endochondral ossification by inhibiting chondrocyte differentiation toward hypertrophy. In the present study, we investigated the effect of PTH on the expression of COL10 in MSCs from OA patients and analyzed the potential mechanisms related to its effect.

Method: MSCs were obtained from aspirates from the intramedullary canal of donors (60–80 years of age) undergoing total hip replacement for OA. Cells were cultured for 2–3 passages in DMEM high glucose supplemented with 10% fetal bovine serum, 100 U/ml penicillin, and 100 μg/ml streptomycin. Cells were then incubated for 0–24h without (Control) or with 100 nM PTH (1–34). Cells were lysed and proteins were separated on 10% acrylamide gels and transferred to nitrocellulose membranes. Protein expression was detected by Western blot using specific antibodies directed against COL10, p38, phosphorylated-p38 (p-p38), SAP/JNK, phosphorylated-SAP/JNK (p-JUNK). GAPDH was used as a housekeeping gene. Protein levels were analyzed using a Bio-Rad VersaDoc equipped with a cooled CCD 12 bit camera.

Results: Results showed that PTH inhibited in a time-dependent manner the expression of COL10 in MSCs from OA patients. The level of expression reached 21% of control (79% inhibition) after 24h. This inhibitory effect of PTH was reversed by Calphostin C, an inhibitor of protein kinase C. To further investigate the mechanism of action related to the effect of PTH on COL10 expression, we measured the phosphorylation of p38 and showed that PTH also inhibited this phosphorylation, which is an indicator of its activity. The level of phosphorylation reached 74% of control after 3h and stayed stable thereafter. Similarly, treatment of MSCs with PTH suppressed the phosphorylation of JNK, another major stress-activated MAP kinase. The level of phosphorylation reached 65% of control after 6h and returned to control values after 24h.

Conclusion: Results of the present study suggested that PTH may be a potential regulator of COL10 expression in MSCs from OA patients. Results also suggested a role for the protein kinase C and the p38/JNK pathways in this regulation. p38 and JNK are serine and threonine protein kinases that are activated by osmotic pressure, stress, and cytokines. It is therefore not surprising that their activities were elevated as OA (degenerative joint disease) is a result of trauma or infection to the joint and is characterized by an up-regulation of cytokines. Further studies are however necessary to better understand the role of these molecules in hypertrophy.


Lynda Loucks Eric Bohm

Purpose: There remains some debate over the impact of obesity on complications and function following total joint replacement. The purpose of this study was to examine the relationship between BMI, self reported complications, function and satisfaction using data from a large prospectively collected dataset.

Method: A total of 5364 procedures with complete one year post operative data were obtained from a Canadian joint replacement registry for analysis. Self reported complications after one year included re-operation, DVT, PE, dislocation and infection requiring antibiotics. BMI was classified as either non-obese (BMI30kg/m2). Satisfaction was collapsed into dichotomous categories: satisfied or unsatisfied. Pre and post operative scores from the Oxford 12 were also included.

Results: The mean age of the total hip replacement (THR) group was 67.1 yrs (+/−11.8) with a mean BMI of 29.8 (+/−6.4). The total knee replacement (TKR) group’s mean age was 68.2 yrs (+/−9.99) with a mean BMI of 33.0 (+/−7.0). Ninety percent (90.6%) of THR patients were satisfied one year after surgery compared to only 81.9% of TKR patients (p< 0.0001). For TKR patients, larger BMI was associated with both satisfaction and self-reported complications; obese patients reported being satisfied 82.4% of the time versus non-obese at 76.9% (p=0.037). Complication rates for obese TKR patients were 11.9% and 7.9% for non-obese (p=0.064). For THR patients, a similar relationship did not exist between BMI and satisfaction; however, it was observed for complications. Obese patients reported a complication rate of 7.4% versus 4.2% (p=0.02) for non-obese. Improvements in Oxford 12 scores were noted across all groups; mean improvement was 22 points in the THR group and 15 points in the TKR group, irrespective of BMI. Improvements in Oxford 12 scores were associated with complications; THR patients reporting complications showed mean improvements of 17 points versus 23 for those who did not (p< 0.0001). TKR patients reporting complications had mean improvements of 10 points versus16 for those who did not (p< 0.0001). Satisfaction was also related to Oxford 12 score; THR patients who were unsatisfied demonstrated an Oxford 12 improvement of only 9 points versus 24 points for the satisfied patients (p< 0.0001). Unsatisfied TKR patients demonstrated an improvement of only 4 points compared to 18 points for satisfied patients, (p< 0.0001).

Conclusion: THR patients were younger and more satisfied than TKR patients. There appears to be a positive relationship between BMI and complication rates for both TKR and THR. A larger BMI was related to increased satisfaction in TKR, it was unrelated in THR. Satisfaction was related to degree of functional improvement which, in turn, was curtailed by complications. It is therefore prudent to advise patients to reduce BMI prior to surgery to mitigate complications; however superior or equivalent satisfaction rates and positive functional improvement can be expected post surgery.


Frank N Schnell Stephen D Miller

Purpose: This study was designed to evaluate post-total joint arthroplasty patients who were sent for a chest CT scan in order to determine the clinical factors that were most likely to be associated with, and predictive of, a radiologic diagnosis of pulmonary embolism in the acute, postoperative period.

Method: The current study involved a review of 540 total knee replacements and 543 total hip arthroplasty procedures performed from June 2008 to September 2009. All patients received postoperative VTE prophy-laxis using LMWH, as per the protocols established by the Alberta Bone and Joint Initiative, and consistent with the recommendations of the American College of Chest Physicians (2008). A pulmonary CT scan was ordered for patients in situations where

a pulmonary embolism was strongly suspected

for those who lacked a clear alternative diagnosis as an explanation for their findings

when steps to correct the suspected underlying condition failed to normalize results, or

in situations where the diagnosis (i.e. new-onset atrial fibrillation) warranted further investigation to rule out a PE as a possible cause.

Patients referred for multidetector computed tomography to investigate the possibility of pulmonary embolus were identified, and subjected to a chart review.

Results: Forty-two patients underwent a pulmonary CT scan investigation to rule out pulmonary embolus. Of these, 15 patients had undergone hip surgery, and 27 had undergone a total knee replacement. Of the 42 patients, 34 exhibited hypoxemia as their major presenting sign (oxygen saturation less than 90% on room air), with or without other signs or symptoms. Four patients presented with tachycardia alone, and 2 patients presented with chest pain, of which one patient had an associated arrhythmia. Of the 34 patients presenting with unexplained postoperative hypoxemia, 25 were patients who had undergone total knee replacement, and of these 25 patients, 14 (56%) were found to have a pulmonary embolus on CT scanning of the lungs. There were no PE’s identified in the post-hip population. None of the patients with PE’s presented with subjective dyspnea or chest pain. There were no fatalities as a result of PE.

Conclusion: The overall high rate of detection of pulmonary embolism in our postoperative population is due the very close monitoring of pulse oximetry combined with the improved sensitivity of imaging modalities. Hypoxemia is emerging as the clinical sign that is most sensitive to the possibility of a PE in the post-knee arthroplasty patient. Reliance on clinical symptoms such as chest pain, dyspnea, or even tachycardia is no longer appropriate. It is recommended that oxygen saturation, as measured by pulse oximetry, should be monitored regularly on all post-arthroplasty patients. Hypoxemia should lead to a prompt and thorough medical workup. If an obvious explanation for the hypoxemia cannot be identified, the patient should undergo a multidetector CT scan to rule out a pulmonary embolus.


James P McAuley Kory D Charron Cecil H Rorabeck Robert B Bourne Steven JM MacDonald

Purpose: The purpose of this study was to investigate the mid to long term (minimum 10 years follow-up) survivorship of the AMK total knee arthroplasty (TKA), as well as determine the effect of implant fixation on outcome.

Method: Between 1988 and 2000, 1074 AMK primary total knee arthroplasties were preformed on 843 patients. All diagnosis included, the distribution was 90% osteoarthritis (971), 7% inflammatory arthritis (76) and 3% other diagnoses (27). Average time from surgery was 15 years (range 10–21 years). Average age at primary procedure was 68 years (range 22–99). Fifty-six percent were female (599) and 44% male (475). Preoperative alignment consisted of 56% varus (601) and 17% valgus (182). Ninety percent (968) had patella resurfacing performed, 62% (661) received cemented TKA fixation, on 32% hybrid fixation (cemented femoral component, cementless tibial tray) was performed and 6% (66) had cementless fixation. Two hundred thirty-seven cases were deceased before 20 years follow-up (22%).

Results: At 10 to 21 years follow-up, 129 revisions were performed (12%). The most common reasons for revision were polyethylene wear, particle induced osteolysis, instability and pain (43% of revisions). Implant fixation significantly influenced the rate of revision with cemented fixation having a 6.7% rate of revision (44/661), hybrid fixation a 14% revision rate (47/336) and cementless a 36.4% revision rate (24/66). Excluding infections (11 cases), overall Kaplan-Meier survivorship at five, 10 and 15 years was 96.4%, 91.9% and 85.8%, respectively. At 20 years the predicted Kaplan-Meier survivorship was estimated at 83.5% (no revisions beyond 17.5 years). Cemented fixation was associated with significantly better survivorship than hybrid and cementless fixation (p< 0.0001). At 5, 10 and 15 years cemented AMK TKA survivorship was 97.5%, 94.9% and 91.9% respectively (no revision performed beyond 13.5 years). For hybrid fixation the survival at 5, 10 and 15 years was 97.8%, 92.2% and 85.1% respectively. Cementless AMK THA had a Kaplan-Meier survivor-ship of 88.9%, 78.2% and 57.4% at 5, 10 and 15 years respectively.

Conclusion: Cemented fixation had superior outcomes compared to cementless and hybrid fixation with the most common reasons for revision being polyethylene wear and osteolysis. To our knowledge this the first medium to long term follow-up of the AMK TKA and it demonstrates that method of fixation had a major influence on revision rates and survivorship.


Mark Harrison Alice Aiken Brenda Brouwer Caroline Pukall Dianne Groll

Purpose: To determine the extent to which, a medically monitored rapid weight-loss program will improve pain, psychological status and functional abilities for morbidly obese women with knee osteoarthritis.

Method: 34 women (age 40 to 65) with morbid obesity and severe osteoarthritis of the knee that presented to an orthopedic surgeon for total knee arthroplasty were offered enrollment into a medically supervised weight loss program prior to consideration of a total knee replacement. Twenty-six subjects chose to participate in the weight loss program. They were enrolled in the Dr. Bernstein diet program, (a low-calorie, low-fat diet) at no cost to them. We collected the following questionnaires at enrollment and every six weeks while they remained in the weight loss program: WOMAC, SF36, Self-Efficacy, Health Locus of control, Dieting beliefs scale, Body image state scale, and the Beck depression inventory as well as Functional tests, namely the Timed up and go (TUG) and 6 minute walk test (6MWT). Our hypothesis was that weight loss would be associated with dramatic improvements in pain, self-report quality of life measures, psychological variables, and measured functional abilities for those patients who were successful in the weight loss program.

Results: At enrollment the mean age was 58.5 years and mean BMI was 47.8.

Subjects were significantly disabled with WOMAC (total) scores of 48+/ − 7 and impaired function in both the 6 minute walk test 229+/ − 146 metres and the timed up-go test 5.9+/ − 11.

(table removed)

Subjects lost an average of 32 kilograms (range 14 to 50 kg) after six months of dieting.

Weight loss was associated with dramatic improvements in pain(p < .01), self-report quality of life measures (p < .01) and measured functional abilities (p < .01).

Successful weight loss was associated with patients’ self-report of no longer requiring TKA for their knee OA.

Initially 100% of subjects felt that they required surgery. This decreased to 9.5% after six months of weight loss.

Conclusion: A low-fat, low-calorie medically monitored weight loss program (Dr. Bernstein Diet Clinics Inc.) is effective for achieving significant weight loss in women with severe knee osteoarthritis and morbid obesity. Weight loss leads to significant improvements in pain and functional abilities and alleviates or delays the need for knee replacement surgery in the majority of middle-aged, morbidly obese women.


Anna Potapov Pascal-André Vendittoli Jean-Michel Laffosse Martin Lavigne Michel Fallaha Michel Malo

Purpose: Antero-medial parapatellar skin incision in total knee arthroplasty (TKA) provides excellent surgical exposure with minimal skin incision length. However, it is associated with the infrapatellar branch of the saphenous nerve section, leading to antero-lateral knee hypoesthesia and sometimes painful nevroma. We hypothesized that

antero-lateral skin incision in TKA produces a lower rate of hypoesthesia compared to the medial parapatellar cutaneous approach, and

reduced hypoesthesia is linked with less discomfort and possibly a better clinical outcome.

Method: A total of 69 knees in 64 patients who underwent TKA were randomized for antero-medial (n=35) or antero-lateral (n=34) skin incision. Mean age was 66.4±8.2 years. Functional outcome was assessed by WOMAC, KOOS and SF-36 scores pre-operatively and at six weeks, six months and one year follow-up. Range of motion (active and passive flexion and extension) was measured. The area of hypoesthesia was analyzed in a standardized manner by an independent observer using a calibrated Semme-Weinstein monofilament applied on 13 reference points. A digital photograph was taken, and the area of hypoesthesia was then measured informatically (Mesurim Pro® software). Patient satisfaction with their scar and their surgery was evaluated. Statistical analysis was carried out with p< 0.05 considered as significant.

Results: The two groups were comparable pre-operatively. There was no significant difference in functional outcome (WOMAC, KOOS, SF-36 scores) at six weeks, six months and one year between the two groups. Active and passive ranges of motion were comparable. The area of hypoesthesia and the number of non-perceived points in the monofilament test were significantly lower after antero-lateral incision at six weeks (p=0.007 and p=0.02, respectively) and 6 months (p=0.02 and p=0.005, respectively). At one year, the area of hypoesthesia was lower in the antero-lateral group, but was not significant (p=0.08). Antero-lateral incision patients reported a lower rate of subjective sensitivity loss and anterior knee pain at six weeks, six months and one year.

Conclusion: Antero-medial and antero-lateral parapatellar skin incisions in TKA have a similar functional outcome. However, antero-lateral cutaneous incision produces a lower rate of hypoaesthesia and less anterior knee pain in the early recovery period.


Charles C Secretan Lauren Beaupre D. William C Johnston Guy Lavoie

Purpose: Despite the excellent results of total knee arthroplasty (TKA), controversy over whether or not to resurface the patella persists. Anterior knee pain, which occurs with variable frequency, continues to be a problem in a subset of the TKA patient population. Some clinicians advocate resurfacing all patellae while others cite the complications attributed to patellar resurfacing as reasons to avoid this aspect of the procedure. Still others favour selective resurfacing based on subjective criteria. To address this clinical controversy, we prospectively randomized patients receiving TKA into two groups, those receiving patellar resurfacing and those left without resurfacing to determine clinical outcomes and revisions at five and 10 years postoperatively. Our primary objective was to compare the revision rate following TKA between the two study groups. Secondarily, we compared pain and function at five and 10 years and knee range of motion (ROM) over the first year.

Method: Patients receiving TKA were prospectively enrolled in the study and randomized intraoperatively to either receive patellar resurfacing or have no patellar intervention. All surgeries were performed through the standard medial parapatellar approach. The Smith and Nephew Profix TKA system was implanted in all cases and all subjects followed a standardized post-operative regimen. Subjects were assessed pre-operatively and at 6 months, 1, 3, 5 and 10 years postoperatively for knee ROM, function, and pain using the WOMAC and SF-36 questionnaires. Re-operations and revisions were also documented.

Results: Thirty-nine patients were enrolled in the study. There was 83% patient retention at five years and 74% at 10 years. Study groups were similar in baseline characteristics. At five years, three (18%) revisions had been performed in the retained patella group and one (5%) in the resurfaced group (p=0.31). There were no further revisions between five and 10 years. ROM was similar between the groups at all evaluations (p> 0.05). SF-36 and WOMAC scores demonstrated that both groups improved their pain and function significantly following surgery (p< 0.04).

Conclusion: The decision whether or not to resurface the patella during TKA remains controversial. This study demonstrated that initial results with either technique are comparable, but it appears that there may be clinically significant differences by five years postoperatively. These trends continued throughout the study and were statistically significant at the 10 year mark. Revision surgery was required in 18% of the retained group compared to 5% in the re-surfaced group.


Robert Wallace Robert B Bourne Richard W McCalden Steven JM MacDonald Kory D Charron

Purpose: There is no consensus whether the posterior cruciate ligament (PCL)should be preserved (CR) or sacrificed (CS) during primary total knee replacement (TKR). The purpose of this study was to compare the greater than 10 year survivorship and health related outcomes of CR and CS TKRs using a single implant system.

Method: Between 1996 and 2000, 478 Genesis II Primary TKRs were inserted in 414 patients. Excluding those with a primary diagnosis other than osteoarthritis, body mass index greater then 40, history of prior patellectomy, fusion or osteotomy, 358 cases in 310 patients were included. 134 (37%) had a PCL preserving (CR) and 224 (63%) had a PCL sacrificing implant (CS). The two patient cohorts were compared for Kaplan-Meier survivorship, health-related outcomes (Knee Society scores, WOMAC, SF-12), range of motion (ROM) and radiographic loosening or wear.

Results: Mean follow-up was 11.87±1.04 years for CR and 10.96±0.87 years for CS (p=0.001). Four cases were revised for infection. No significant differences were noted between the CR and CS Genesis II cohorts at 10 year Kaplan-Meier survivorship excluding infections (CR 0.984±0.011, CS 0.986±0.008, p=0.30). Overall revisions were two for CR (1.5%, no infections) and seven for CS (1.7%, four for infection; 1.3% excluding infections). Revision rates were not significantly different between groups including or excluding infections (p=0.493 and p=1.00 respectively). CS had significantly greater postoperative ROM than CR (CS=114.20±13.60, CR=111.35±12.38, p=0.024). At 10 years, no differences were observed in satisfaction, health-related outcomes or radiographic wear/loosening. Crepitus was reported more frequently in CS design.

Conclusion: Most studies comparing PCL sacrificing (CS) versus retaining (CR) TKRs are short term. In this large, long term, single implant CR versus CS study, no differences were found in Kaplan-Meier survivorship, health-related outcomes or patient satisfaction. The CS design had more range of motion, but also a higher incidence of peripatellar crepitus than the CR design. We conclude that both CR and CS TKR designs can yield excellent long term clinical outcomes.


K Leighton Kelly Trask

Purpose: Intra-articular (IA) injections of corticosteroids and hyaluronic acid (HA) products are used to treat patients with knee osteoarthritis pain that has not responded to more conservative treatment. Corticosteroids are a standard of care despite only suggestive clinical evidence of 12 or more weeks of pain relief.

Method: A double-blinded, randomized, active controlled, multicenter non-inferiority trial with 442 subjects provided a pragmatic comparison of HA to methylprednisolone. Both groups received one intrar-ticular injection, and underwent pain and function evaluations over 26 weeks. The primary endpoint for study success was WOMAC pain responder rate at 12 weeks. The outcome of two prior trials influenced the patient selection criteria and provided a saline cohort for propensity score analyses comparing HA and methylprednisolone to saline.

Results: The responder rate of HA was non-inferior to methylprednisolone at 12 weeks. Reductions in WOMAC pain, stiffness and physical function scores at all time points, and improvements in time to ‘get-up-and-go’ and walk 10 meters occurred in both treatment groups. The trends favored the HA responder rates at the later time points while the methylprednisolone rate decreased significantly by 26 weeks. Propensity score analyses confirmed that the responder rates of meth-ylprednisolone and HA were statistically significantly superior to a saline control at 12 weeks.

Conclusion: The responder rate from a single injection of HA was non-inferior to methylprednisolone at 12 weeks, and the trend favored HA at later time points. The responder rates of HA and methylprednisolone were statistically significantly greater than that of saline at 12 weeks.


Philip A O’Connor Robert B Bourne Steven JM MacDonald Richard W McCalden Cecil H Rorabeck Kory D Charron

Purpose: High contact stresses and wear after total knee replacement (TKR) has been a problem. Mobile bearing TKRs have been advocated as a means to increase load bearing area, reduce contact stresses and minimize wear. The purpose of this study was to compare two, large, consecutive cohorts of TKR patients with greater than 10 years follow-up, one with a fixed bearing and one with a mobile bearing design.

Method: One hundred and three SAL II mobile bearing TKR’s were compared to a gender, age, BMI and time from surgery matched fixed bearing Genesis II cohort of equal size. All surgeries were performed between September 1993 and December 2000 (average follow-up, 11.64±1.64 years). Inclusion criteria included patients with osteoarthritis of the knee. Exclusion criteria included revision arthroplasty, inflammatory arthritis, a prior osteotomy or a prior patellectomy. The > 10 year Kaplan-Meier survivorship, health-related outcomes (Knee Society scores, WOMAC and SF-12), radiographs and retrieved implants for the fixed and mobile bearing TKR cohorts were compared.

Results: Fixed bearing TKRs demonstrated better 10 year Kaplan-Meier survivorships for any re-operation, 1.000±0.000 compared to 0.969±0.018 for mobile bearings (Genesis II and SAL I/II respectively). Revision rates were significantly different between groups with fixed bearing having no revisions and mobile four revisions (3.9%). No cases were revised for sepsis. Mobile bearing revisions were for pain (1), patellar maltracking (1), polyethylene wear (1) and aseptic loosening (1). At 10 years, health-related outcomes were similar between the two cohorts. Fixed bearing TKRs demonstrated more range of motion (111.42±12.76 vs 107.19±14.74 degrees) although not significant (p=0.052). Wear was more frequently noted in mobile bearing TKRs on > 10 year radiographs.

Conclusion: In this comparison of two contemporary TKRs, the fixed bearing TKR outperformed the mobile bearing TKR.


Paul RT Kuzyk Gordon Higgins James Tunggal Emil H Schemitsch James P Waddell

Purpose: The purpose of this study was to evaluate the accuracy and precision of 3 common methods used to produce posterior tibial slope during total knee arthroplasty.

Method: The study population consisted of 110 total knee arthroplasties in 102 patients that underwent total knee arthroplasty. All procedures were performed using a standard medial parapatellar approach and all knees were replaced using the Scorpio Knee System (Stryker, Mahwah, NJ) of implants and instruments. Three treatment groups were identified retrospectively based on the method used to produce the posterior tibial slope. Group 1 used an extramedullary guide with a 0 degree cutting block tilted by placing 2 fingers between the tibia and the extramedullary guide proximally and three fingers between the tibia and guide distally to produce a 3 degree posterior slope (N=40). Group 2 used computer navigation (Stryker Navigation System, Stryker, Mahwah, NJ) to produce a 3 degree posterior slope (N=30). Group 3 used an extramedullary guide placed parallel to the anatomic axis of the tibia with a 5 degree cutting block to produce a 5 degree posterior slope (N=40). Posterior tibial slope was measured from lateral radiographs by 2 independent reviewers that were blinded to the treatment group. The reported posterior tibial slope for each sample was an average of these two measurements. Accuracy of the treatment group was evaluated using a one sample t test. Groups 1 and 2 were tested for an ideal slope of 3 degrees, and Group 3 was tested for an ideal slope of 5 degrees. An a priori sample size calculation with α=0.05 and β=0.20 showed that at least 24 samples in each treatment group were required to determine a difference of 1.5 degrees between the treatment group mean posterior tibial slope and the ideal posterior tibial slope.

Results: The mean posterior slope measurements for treatment Group 1 (4.15±3.24 degrees) and treatment Group 2 (1.60±1.62 degrees) were both significantly different than the ideal slope of 3 degrees (p=0.03 for Group 1 and p< 0.01 for Group 2). This indicates that treatment Groups 1 and 2 failed to accurately produce the ideal posterior tibial slope of 3 degrees. The mean posterior tibia slope of treatment Group 3 (5.00±2.87 degrees) was not significantly different than the ideal posterior tibial slope of 5 degrees (p=1.00). This indicates that Group 3 accurately produced the ideal tibial slope of 5 degrees.

Conclusion: The most accurate method to produce posterior tibial slope was the 5 degree cutting block with an extramedullary guide. Computer navigation had the lowest standard deviation and therefore was the most precise method. However, computer navigation was not as accurate in producing the desired posterior tibial slope as the extramedullary guide with the 5 degree cutting block. The manual method of producing tibial slope with an extramedullary guide and a 0 degree cutting block was the least precise method and not as accurate as the extramedullary guide with a 5 degree cutting block.


Richard W McCalden Kory D Charron Xunhua Yuan Robert B Bourne Douglas D Naudie Steven JM MacDonald Abigail E Thompson

Purpose: The purpose of this prospective blinded randomized control trial was to compare the stem migration of two cemented stem designs using radiostereometric analysis (RSA). This was essentially a safety study in which our hypothesis was that the newer design (CPCS, Smith and Nephew Inc) would demonstrate similar micro-motion to the well-established Exeter (Stryker) design.

Method: Thirty patients were consented and enrolled into a blinded RCT in which 15 patients received a dedicated RSA CPCS stem and 15 patients received a RSA Exeter stem. Both stems are collarless tapered polished cemented stems, the only difference being a slight lateral to medial taper with the CPCS design. Outcome measures were compared (Hip Society Score, WOMAC, SF-12). RSA analysis was conducted immediately postoperatively, at 6 weeks, 3 months, 6 months, 1 year and 2 years.

Results: No difference was found in any of the outcome measures pre-operatively or postoperatively. At 2 years, stem subsidence for the CPCS stem was approximately half that seen for the Exeter stem (0.565±0.189mm and 0.981±0.209mm respectively, p< 0.0001). In contrast, posterior (internal) rotation of the CPCS was approximately twice that of the Exeter stem (1.496±1.215° and 0.716±0.818° respectively, p=0.221). Other migration patterns were no different between stems.

Conclusion: As expected with this stem design, both stems showed some axial and rotational migration within the cement mantle. The subtle differences in design may explain the differences in migration patterns. Our data suggests that the newer CPCS design should perform well over the long-term.


Paul E Beaulé Frank Smith James N Powell John Antoniou Robert B Bourne Martin Lavigne Etienne Belzile Emil H Schemitsch Donald Garbuz

Purpose: Recently, there has been concern raised on the occurrence of pseudotumors after metal on metal hip resurfacing. A pseudotumor is defined as a local soft tissue mass associated with localized bony and/or tissue (muscle) destruction. The primary purpose of this study is to determine the incidence of this complication in several high volume Canadian academic centres.

Method: Nine of the 11 Canadian academic centres who perform metal on metal hip resurfacings were surveyed. The number of metal on metal hip resurfacing arthroplasties performed at each centre was first determined, as were the number of those who have presented with a pseudotumour, and subsequently gone on to revision surgery. The basic demographics of the group were recorded, as were the radiographic and implant design variables for those cases presenting with a pseudotumour.

Results: A sample of 3,400 hip resurfacing arthroplasties performed between 2002 and December 2008 were surveyed. Demographics were tabulated for a sub-sample of these patients. 76% were male, the mean length of follow-up was 3.02 years, mean BMI was 28.65, and mean age was 52.10 years. Three of 3,400 cases presented with a pseudotumour, an incidence of .09%.

Conclusion: Although pseudotumors remain a concern after metal on metal hip resurfacing, the incidence at short to mid term follow-up is very low in this multi-centre academic survey. This information is significantly lower than what other groups have recently reported. Continued close monitoring is required in order to determine what clinical factors are at play.


John Antoniou Alain Petit Vassilios S Nikolaou Constantin Papanastasiou Fackson Mwale David J Zukor Olga L Huk

Purpose: Several studies have shown elevated levels of metal ions in blood of patients with metal-on-metal (MM) total hip arthroplasty (THA). The outstanding question that remains is the clinical impact of these elevated ion levels. Even though it is well known that exposure to heavy metals such as lead, copper, mercury, nickel, and cadmium) may lead to significant alterations in human sperm morphology and motility, less is known on the effect of Co and Cr on semen parameters. The aim of the present study was to investigate the effect of metal ions on the semen of males of child fathering age with MM hip arthroplasty.

Method: Semen was collected form 10 patients between 41 and 49 years old (mean = 45±6 years) by masturbation after 2–3 days of abstinence. Samples were examined within 1h after ejaculation for morphology, motility, and number of sperm cells following standard criteria from the World Health Organization (WHO). Co and Cr concentrations were measured in both the seminal plasma and in the blood of patients by inductively coupled plasma-mass spectroscopy (ICP-MS). Since spermatozoa membrane polyunsaturated fatty acids are vulnerable to attack by reactive oxygen species (leading to peroxide formation), peroxide concentrations were measured in both the seminal plasma and the blood of patients.

Results: Results showed that the concentration of both Co and Cr ions was significantly lower in the seminal plasma than in the blood of the patients. Results also showed that the levels of peroxides were lower in the seminal plasma than in the blood plasma of these patients. Importantly, the ejaculate volume, the sperm density, the total sperm count, the pH, and the percentage of cells with normal morphology were in the range of the WHO criteria for fertile population and also in the range of reference patients in the city of measurements. However, the viability was a little bit lower than what was observed in a fertile population without prosthesis.

Conclusion: The presence of Co and Cr ions in the blood of males of child fathering age with MM hip arthroplasty raised concerns about the quality of semen in these patients. Results of the present study strongly suggest that the raised of Co and Cr had no significant effect on sperm parameters of young patients with MM prosthesis. The methods used to identify potential normal and fertile semen samples are still contradictory and not exactly defined. Studies showed for example that only total numbers of sperm with progressive mobility are significantly different in the fertile than in sub-fertile men, while others suggested that the fertile population should be defined by sperm concentration or sperm morphology. In conclusion, results suggest that Co and Cr ions generated from MM prosthesis have no significant effect on the sperm parameters of young patients of child fathering age. Further longitudinal studies are however necessary to conclusively determine the effect of metal ions from MM prosthesis on sperm parameters.


Richard W McCalden Douglas D Naudie Robert B Bourne Steven JM MacDonald David W Holdsworth Xunhua Yuan Kory D Charron

Purpose: Efforts to decrease polyethylene wear have lead to advances in polyethylene and counter-face technology for total hip replacement. In particular, the use of highly cross-linked polyethylene (XLPE) and more recently, oxidized zirconium (Oxinium) heads, have demonstrated significant in-vitro improvements in THR wear. This study reports on the early clinical performance and wear (measured with RSA) of an randomized controlled trial (RCT) comparing Oxinium and CoCr heads on XLPE and conventional polyethylene (CPE).

Method: Forty patients were enrolled in a RCT and stratified to receive either an Oxinium (Ox) or CoCr head against either XLPE or CPE (ie 10 patients in each group). All patients had otherwise identical THRs and had tantalum beads inserted in the pelvis and polyethylene for wear analysis. There were no significant differences between groups with respect to patient demographics and the average age was 68 years (range 57–76) at index procedure. RSA wear analysis was performed immediately post-op, at six weeks, three and six months and then at one and two years. All patients are a minimum of four years post-op (average 4.6, range 4 – 5.8). Patients were followed prospectively using validated clinical outcome scores (WOMAC, SF-12, Harris Hip scores) and radiographs.

Results: All health-related outcomes were significantly improved from pre-operative with a mean Harris Hip score and WOMAC at last follow-up of 90.9 and 80.2, respectively. Total 3D femoral head penetration at two years for each group were the following: CoCrXLPE (0.068±0.029mm); OxXLPE (0.115±0.038mm); CoCrCPE (0.187±0.079mm); and OxCPE (0.242±0.088mm). Thus, OxCPE was significantly higher than OxXLPE and CoCrXLPE but not CoCrCPE (p=0.001, p> 0.0001 and p=0.094, respectively). In other words, head penetration was higher with CPE compared to XLPE but there was no significant difference between Ox and CoCr heads. Similarily, regardless of head type (ie combining similar poly types), there was a significant difference in 3D head penetration at two years between CPE and XLPE ( CPE 0.213±0.086; XLPE 0.093±0.041, p> 0.0001).

Conclusion: The early results of this RCT, using RSA as the wear analysis tool, indicate a significant improvement in wear with XLPE compared to CPE. However, it failed to show a clear advantage to the use of Oxinium over CoCr against either polyethylene. Longer follow-up is required to determine steady-state wear rates (after bedding-in) and allow comparison between bearing groups.


Nelson V Greidanus Donald Garbuz Bas A Masri Allan Gross Michael Tanzer Clive P Duncan

Purpose: The purpose of this study was to evaluate the clinical effectiveness and outcomes of the ‘abductor sparing’ MIS Anterolateral approach (MIS Watson Jones/G3) in comparison to the MIS Direct Lateral and MIS Posterolateral approaches in primary total hip arthroplasty.

Method: A multicentre, prospective, randomized controlled trial was designed to evaluate for the superiority of the new MIS Anterolateral approach (MIS Watson Jones/ G3). The sample size calculation was performed for alpha .05, power .90, to evaluate for effect size 0.5 in WOMAC using repeated measures analyses with baseline WOMAC as covariate. A total of 156 patients consented to participate in the trial and patients were assigned to MIS Antero-lateral approach or alternate MIS approach (MIS Direct Lateral or MIS Posterolateral). Patients were subjected to standardized anaesthetic and perioperative management protocols and were evaluated at standardized intervals to evaluate endpoints of early recovery (3 months) as well as endpoints of 12 and 24 months respectively. The primary outcome of interest was WOMAC, however secondary outcomes included SF-36, as well as parameters of health resource utilization and complications. Univariate and multivariate analyses were perfomed.

Results: Patient groups were found to be similar at baseline with regards to demographics and baseline quality of life outcomes (p> .05). Multivariate and repeated measures analyses demonstrated no superiority of the MIS Anterolateral approach on outcomes of WOMAC and other quality of life measures in comparison to MIS Direct Lateral and MIS Posterolateral approaches (p> .05). Health care resource utlization was also similar with length of stay, blood transfusion requirements and complications (p> .05).

Conclusion: Our multicentre, prospective, randomized clinical trial demonstrates that the MIS Anterolateral approach is not superior to alternate MIS surgical approaches when evaluating outcomes of quality of life, complications, and health resource utilization. Surgeons should consider these outcomes, complications, and other relevant advantages and disadvantages of select surgical approaches when deciding on a technique for use in their orthopaedic practice.


Jonathan Loughead Philip A O’Connor Kory D Charron Cecil H Rorabeck Robert B Bourne

Purpose: The purpose of this study was to determine the greater than 20 year survivorship of the PCA total hip arthroplasty (THA) in patients with severe hip osteoarthritis.

Method: A prospective follow-up of 315 consecutive patients treated with a PCA cementless THA in patients with hip osteoarthritis was performed. Patients had postoperative assessments and radiographs every two years. Overall THA, femoral stem and acetabular cup revisions and Kaplan-Meier survivorship was determined. Revision rates and survivorship was also investigated across gender.

Results: The mean age of our patients was 61 years old (range 20 to 86) with 47% female patients. 226 cases used a 26mm articulation and 89 cases a 32mm articulation. At 23 years follow-up, 188(60%) patients were alive with retained implants while 85(27%) were deceased with still implants that were functioning well. Forty-two cases (13%) were revised (30 sockets, 13 stems), five of which later deceased. The 20 year Kaplan Meier survivorship for the overall THA, stem component and acetabular cup were 86%, 97% and 90% respectively. Survivorship of the acetabular cup for 26mm and 32mm articulations was 92% and 85% respectively (p=0.016). Females had a worse THA survivorship than males, 82% and 91% respectively (p=0.036).

Conclusion: The PCA cementless THA has performed well beyond 20 years with 26 mm articulations doing better than 32 mm, and male gender associated with better outcomes. The authors postulate that polyethylene thickness is key to predicting failure.


Krista Goulding Paul E Beaulé

Purpose: LFCN neuropraxia is a known complication of the anterior approach to the hip joint. The objective of this study was to define the incidence, functional impact and natural history of this neuropraxia in the anterior approach after both hip resurfacing (HR) and primary total hip arthroplasty (THA).

Method: Between September 2006 and January 2008, 132 consecutive patients underwent a direct anterior hip approach (DAA) (55 THR; 77 HR). Sixty-two patients were female and 70 were male; the mean age was 55.54 (range, 29.9 to 88.7). Self reported questionnaires for sensory deficits of LFCN, a neuropathic pain score (DN4) as well as SF-12, UCLA and WOMAC scores were completed. A subset of 60 patients (30 THA, 30 resurfacing) was evaluated at two time intervals (6 and 12 months).

Results: One hundred and seven patients (81%) reported LFCN neuropraxia, with a mean severity score of 2.32/10 (SD, 2.11); mean DN4 score of 2.42/10 (SD, 2.37). Hip resurfacing had a higher incidence of neuro-praxia compared to THA: 91% versus 67% (p=0.02), respectively. No functional limitations were reported on SF-12, WOMAC or UCLA scores. Of the subset of 60 patients, 53 (88.3%) reported neuropraxia at the six month follow-up interval with only three (5.7%) having complete resolution at 12 months. Patients who reported neuropraxia at both testing intervals did report an improvement in DN4 scores: 3.6 versus 2.5 at 6 and 12 months, respectively (p=0.02).

Conclusion: Although LFCN neuropraxia is a frequent complication after DAA total hip arthroplasty, it does not lead to any functional limitations. A decrease in symptoms does occur over time, with only a small number of patients reporting complete resolution.


Kemi Alo Peter M Lewis Jagannath Chakravarthy Eric S Isbister

Purpose: The modern generation of hip resurfacing arthroplasties was developed in the early 1990’s with one of the original designs being the McMinn Resurfacing Total Hip System. This was a hybrid metal on metal prosthesis, with a smooth hydroxyapetite coated press fit mono block cobalt chrome shell with a cemented femoral component. Although no longer produced in this form, lessons may be learned from this original series of components. With metal on metal resurfacing arthroplasty now facing criticisms and concerns with regard function, bone preservation capability and soft tissue issues such as ‘pseudotumors’, it is the aim of this long-term study to assess the outcome and survival of an original series of resurfacing arthroplasties.

Method: 27 resurfacing arthroplasties were performed in 25 consecutive patients between June 1994 and November 1996. 16 right hips and 11 left were performed in 14 female patients and 11 male patients. The average age at the time of surgery was 50.5 years (SD 7.9, range 30–63). All surgeries were performed by a single surgeon using a posterior lateral approach. Following the initial early care, each patient received bi-annual follow up along with open access to the clinic with any concerns or complications. A retrospective review of the case notes was conducted and outcome scores retrieved from a prospectively updated database. Radiographs were analyzed and a Kaplan Meier survival chart was constructed for the group.

Results: At latest review 3 patients have died (5yrs, 8yrs and 13.8yrs) and 1 patient has been lost to follow up (5yrs). 7 resurfacings have required revision, all due to acetabular loosening, at a mean follow up of 7 years 11months (SD 2.03years, range 4–10). Metallosis was documented in 4 of the revision cases, however no extensive soft tissue inflammation or ‘pseudotumor’ identified. The mean follow up of the remaining 16 hips is 12years and 10months (SD 12.8months, Range 10.4yrs-14.0 years). The Kaplan Meier survival at a minimum follow up of 10 years is 75.8% (95% CI 0.67–0.95). Mean Oxford hip scores at latest follow up was 20.6 (SD 8.8, range 12–38). There was no significant difference between cup inclination angles for the surviving cohort and those who required a revision procedure with mean cup inclinations of 52.5 (SD 5.5, range 45–60) and 58 degrees respectively (SD 9.1, range 50–70)(p=0.255).

Conclusion: This original series of hip resurfacings, with up to 14 years follow up, shows a survival of 76% at the minimum follow up of 10 years. All failures were due to loosening of the smooth backed acetabulum, which with a modern porous coating, failure may have been avoided or delayed. Despite high inclinations angles no soft tissue reactions were identified within this series. No femoral failures were identified suggesting unlike much literature focus, long-term failure may not be related to the femoral head or neck.


Steven JM MacDonald Charles A Engh Douglas D Naudie Charles A Engh Richard W McCalden Abigail E Thompson Supatra Sritulanondha

Purpose: A ceramic head coupled to a metal liner is a proposed new alternate bearing in THA. The authors participated in an FDA approved multicentre prospective, randomized, blinded clinical trial comparing ceramic-on-metal (CoM) to metal-on-metal (MoM) in patients receiving a THA.

Method: 390 patients received the same acetabular component and metal insert. 194 patients received a delta ceramic head (CoM) and 196 received a metal head (MoM). Metal ions were evaluated in 72 patients (36-CoM, 36-MoM). Harris Hip scores, radiographs, and metal ion levels (cobalt, chromium and titanium in serum, erythrocytes and urine) were evaluated pre-operatively and at three, 12 and 24 months.

Results: No patients were lost to follow-up. There were no differences between groups’ baseline demographics and clinical scores. At two years there were no differences in Harris Hip scores, radiographs, adverse events or postoperative complications. Both groups had overall very low median metal ion profiles with no statistically significant differences. 24 month MoM vs CoM; Serum cobalt ( g/L), mean: 1.2(+/−0.5) vs 1.1(+/−0.3), median: 0.66(range: 0.2–5.6) vs 1.0 (range: 0.3–2.7); Serum chromium ( g/L), mean: 1.1(+/−0.5) vs 1.4(+/−0.4), median: 0.86(range: 0.3–6.9) vs 1.2(range: 0.3–4.9). Urine cobalt and urine chromium ( g/day) demonstrated similar trends to serum ion levels.

Conclusion: While CoM is a new bearing surface in North America and not currently FDA or HPB approved, it has been in clinical use globally since 2006. Results of this non-inferiority RCT demonstrated no clinical outcome, metal ion, radiographic or adverse event differences between CoM and MoM cohorts.


Craig White Sasha Carsen Kevin Rasuli Steve Doucette Paul E Beaulé

Purpose: We aimed to measure the early migration pattern of a titanium alloy, tapered, plasma and hydroxyapatite coated femoral stem and any factors associated with subsidence.

Method: Between January 2005–June 2007, 387 Accolade cementless femoral stems (Stryker, Allendale NJ) were implanted at our institution. Seventy-seven had a minimum of two years post operative follow up and a complete set of pre and postoperative radiographs for analysis. Our group inlcuded 45 females with a mean age of 71.4 years, and 32 males with a mean age of 68.5 years. The primary diagnosis was degenerative osteoarthritis in 71 patients, avascular necrosis in two, and post fracture in four patients. The average BMI was 27.1. We measured the canal index to assess bone quality and the canal calcar index to assess the proximal femoral morphology. Immediate postoperative radiographs were assessed for canal fill of the prosthesis and implantation varus/valgus angles. The EBRA-FCA software was used to obtain migration curves for each stem. Best fit curve of subsidence over time was calculated and the data was analysed using a Kaplan Meier survivorship with 1.5 mm of subsidence as an endpoint. We then performed a multivariate and univariate regression analysis for predictors of subsidence.

Results: The mean follow up was 29.3months (24–48). The mean canal index was 0.55 (0.36–0.68) with a mean canal calcar index of 0.54 (0.39–0.79). The average canal fill index at the midpoint of the stem was 80 in 40 stems. A total of 414 radiographs were analysed for the EBRA measurements. Of these 21 (5%) were discarded by the software as they did not meet the criteria for comparability. This led to the exclusion of seven patients, leaving the final study group of 77. All remaining patients had a minimum of four radiographs with an average of 4.6 for analysis. The average subsidence at 24 months was 2 mm and this had risen to 2.4 mm by 36 months postoperatively. When analysed using a Kaplan Meier curve using 1.5 mm as an end point we found a survivorship of 63.4% (52.3–74.5) at 24 months and this had worsened to 41.6% (26.6–56.5) by 36 months. Multivariate and univariate regression analysis of measured variables did not reveal any significant hazard for any factor other than the larger stem sizes doing worse.

Conclusion: Although several cementless tapered stem designs have had an excellent track record, our migration analysis of the Accolade stem is somewhat concerning. Thirty three percent of stems had reached the 1.5 mm subsidence point by two years. This is of concern as work has previously shown this to predict failure of stems with aseptic loosening at ten years with an accuracy of 79%. If these stems go on to fail at the predicted rate this would represent an unacceptably high level of failure. Our data raises serious concerns about the overall clinical performance of this stem design due to poor initial stability and integration.


Helen Razmjou George Athwal Richard Holtby

Purpose: The purpose of this study was to investigate the difference in the level of pre and 6 months post operative objective and subjective measures of disability between patients with full-thickness rotator cuff tears and those with impingement syndrome/partial thickness rotator cuff tears.

Method: This study involved a review of prospectively collected data from a consecutive series of patients who had undergone surgery related to rotator cuff pathology (acromioplasty with or without resection of clavicle for impingement syndrome/partial thickness rotator cuff tears or repair for full-thickness rotator cuff tears). Exclusion criteria included previous surgery, concomitant pathologies, and work-related injuries with an active compensation claim related to the shoulder. Standardized pre and post-operative data (history and clinical examination, including strength assessment) were collected. To measure symptoms and functional levels, all patients completed a disease-specific outcome measure, the Western Ontario Rotator Cuff (WORC) Index which explores five domains of physical symptoms, life style, work, sports, and emotions. Paired and independent non-parametric (Wilcoxon two sample tests, and Wilcoxon signed rank tests) statistics were used where normality of data were violated.

Results: Three hundred and five patients (130 women and 175 men) with a mean age of 58 years (range, 21–82) met inclusion criteria. One hundred and ninety eight (65%) patients had full-thickness rotator cuff tears and 107(35%) had impingement [59 (55%)] or partial thickness rotator cuff tears [48 (45%)]. Patients with full-thickness tears complained of greater weakness, had a higher prevalence of a specific injury such as fall on an outstretched hand, and reported a higher frequency of insidious onset of pain. The full-thickness tear group was significantly weaker in elevation both pre and post-operatively. Patients with impingement syndrome expressed more severe symptoms and more emotional disability prior to surgery and had more physical disability related to lifting and performing activities of daily living and more emotional disability 6 months after surgery. Both groups showed a statistically significant improvement in overall pain, WORC score, and strength 6 months following surgery.

Conclusion: Our results indicate that the extent of rotator cuff pathology and level of physical and emotional disability do not necessarily correlate positively in the early phase of recovery. Patients with less severe rotator cuff pathology tend to be more disabled both before and after surgery. This needs to be considered when planning for return to work and other activities and when assessing treatment outcomes.


Jason Old Pascal Boileau Miguel Pinedo Pablo Vargas Matthias Zumstein

Purpose: The “Hill-Sachs Remplissage” (HSR) is a procedure used in the treatment of anterior shoulder instability associated with an engaging Hill-Sachs (HS) defect. It consists of an arthroscopic capsulotenodesis of the posterior capsule and infraspinatus tendon within the defect. There is currently no evidence that the capsule and tendon heal in the humeral bone defect. Our hypotheses were

that the capsulotenodesis heals in the HS defect and fills at least 50% of its area; and,

that limitation of range of motion compared to the non-operated shoulder would be minimal.

Method: Prospective clinical study. Inclusion criteria:

recurrent anterior shoulder instability;

engaging HS lesion.

Exclusion criteria:

glenoid bone loss;

rotator cuff tear.

Twenty-nine patients underwent an arthroscopic Bankart repair plus HSR. Clinical assessment at a mean follow up of 13.1 months (range 6 to 32 months) consisted of a structured interview and detailed physical examination including range of motion compare to the contralateral shoulder and instability signs. Range of motion was analyzed in two groups according to length of follow-up, Group 1 with less than 12 months follow-up (14 patients); and Group 2 with greater than 12 months follow-up (15 patients). Either a CT arthrogram (25 patients) or an Arthro-MRI (2 patient) was performed at a minimum of six months postoperatively. Four orthopaedic surgeons analyzed the images independently to determine the percentage of healing of the capsulotenodesis.

Results: There was no recurrence of instability at the latest follow-up. There was no statistically significant deficit in forward elevation in either group. Group 1 patients had statistically significant mean deficits as compared to the contralateral side of 15 degrees of external rotation in adduction (ER1), 15 degrees of external rotation at 90 degrees of abduction (ER2), and 1.1 points of internal rotation in adduction according to the Constant score system (ER1). Group 2 patients had statistically significant mean deficits of 4 degrees of ER1 and 11 degrees of ER2, with no significant difference in IR1. There was healing of the capsulotenodesis within the bone defect in all twenty-seven patients. The bone defect was filled more than 75% of its surface in 22 of 29 patients (76%). The remaining seven had between 50 and 75% filling (24%). There was no defect filling of less than 50% in this study.

Conclusion: We demonstrated greater than 50% HS defect filling in all patients in our series after an arthroscopic “Hill-Sachs Remplissage” and filling > 75% in 22 of 29 (76%). Modest deficits of external rotation were demonstrated at greater than 12 months follow-up. While these results suggest that the technical goal of HS defect filling is achievable, longer term studies are necessary to establish whether there is an association between the rate of healing, the functional impairment of external rotation and clinical outcomes.


Richard M Holtby Helen Razmjou Gregory Stranges

Purpose: The purpose of this matched cohort study was to examine the clinical outcome of biceps tendon debridement at two years following surgery.

Method: The study group included patients who had undergone debridement of a tear of less than or equal to 50% of the biceps tendon. The control group did not have biceps pathology and was chosen from the same pool of data and was matched with the study group by sex, age and type of associated pathology. Standardized pre and post operative data on history and clinical examination of all patients had been collected prospectively. The outcome measures were the American Shoulder and Elbow Surgeons (ASES) assessment form, the relative Constant-Murley score (CMS), and the Western Ontario Rotator Cuff (WORC) Index. Paired and independent T-tests were performed.

Results: Review of data identified 122 patients (16 females, 45 males in each group). The mean age was 59 (SD: 11) and 57 (SD: 12) for the study and control groups respectively. Fifty six percent of the subjects in each group (34/61) had impingement or partial thickness rotator cuff tears treated with a decompression (acromioplasty/ decompression). Twenty two patients (36%) had rotator cuff repair, and 5 (8%) had a SLAP repair. A statistically significant improvement was observed in the scores of WORC, ASES and CMS (p< 0.0001) in both groups. The magnitude of change, based on the effect size showed a large change in both groups. There was no statistically significant difference in pre and post-operative scores or recovery between groups.

Conclusion: Low grade tears of the biceps tendon do not appear to produce more disability prior to surgical treatment and are effectively treated with biceps debridement in addition to surgical treatment of associated pathologies.


R. Cole Beavis Alexander I Glogau

Purpose: Little evidence exists to guide rehabilitation following arthroscopic rotator cuff repair (ARCR). It is unclear how new repair techniques may affect postoperative protocols. Our purpose was to determine current practices of members of the Arthroscopy Association of North America (AANA) and the American Orthopaedic Society for Sports Medicine (AOSSM.) Our hypothesis was that wide variation would exist in the postoperative rehabilitation following ARCR and that accelerated protocols would commonly be prescribed after double row ARCR.

Method: A 28 question web-based survey was sent to all active members of AANA and AOSSM via email addresses listed in the specialty society directory. Non-responders were reminded by 2 additional invitations. Results were tabulated and responses reported as a percentage of respondents.

Results: The response rate was 37.7% (797/2112). Most commonly, respondents use a post-operative abduction sling (56.2%) and begin physical therapy within the first 2 weeks (42.1%.) Passive ROM is initiated within 2 weeks (74.1%), active ROM after 6 weeks (55.3%) and strengthening after 6 weeks (64.4%). Unrestricted activities are permitted at 5 months (41.2%.) 85.2% of respondents alter rehabilitation based upon tear size. Protocols were altered based upon tissue quality (86.9%), involvement of subscapularis (68.7%) or biceps tendon (65.2%) but not for workers compensation status (97.1%), smoking (71.5%) or patient age (70.3%.) 81.1% had performed double row rotator cuff repairs; however 95.2% of those do not alter their postoperative protocol based upon repair configuration.

Conclusion: Our results demonstrate wide variation among respondents with regards to immobilization, ROM and return to activity. The majority had performed double row ARCR, however 95.2% of these do not alter their postoperative rehabilitation in patients undergoing double row repair.


Chris B Chant Joy MacDermid Darren S Drosdowech Kenneth J Faber George Athwal

Purpose: The purpose of this study was to identify if preoperative pain scores predict postoperative pain and functional outcomes in patients following rotator cuff surgery and if a threshold where increased risk occurs could be established. Establishing a risk threshold may help identify patients who need increased follow-up or rehabilitation.

Method: One hundred six subjects with rotator cuff pathology requiring operative intervention were prospectively followed. The pain subscale of the Shoulder Pain and Disability Index (SPADI) was used as an indicator of pre-operative pain. Postoperative function one year following surgery was determined using the Simple Shoulder Test (SST). Scores with 40% or more deficit (compared to age matched controls) were classified as poor outcomes. The relative risk (RR) of poor SST scores was calculated across different cutoffs for preoperative pain scores.

Results: Having a high preoperative pain score was associated with a poor outcome following rotator cuff surgery at both the six month and one year followup. Preoperative pain scores did predict postoperative functional scores. As preoperative pain levels increased there was a higher risk of poor functional outcomes. The RR of having a poor SST at 1-year was 2.3, if preoperative pain score was greater than 35/50.

Conclusion: The current study indicates that those patients with high preoperative pain scores (> 35/50 or > 70%) are more than twice as likely to have a poor outcome following rotator cuff surgery. This should inform patients and surgeons for postoperative expectations. Whether closer follow-up, pre-rehabilitation, more intensive postoperative rehabilitation or enhanced pain management can alter this prognosis warrants investigation.


Zafar Iqbal Ahmad Chris Ingham Chris Roberts

Purpose: Frozen shoulder, an excruciatingly painful condition known medically as adhesive capsulitis, affects two million people in Britain. Diabetics and women aged 40–60 are particularly at risk. The current treatment for frozen shoulder includes painkillers, physiotherapy, or surgery. The above presents their own problems, including recurrence of symptoms, failure of therapy, and for surgery: recovery period, anaesthetic and surgical operative risks. In contrast, the therapy involving hydrodilatation injections into the shoulder takes just ten minutes and allows patients to go home immediately. Hydrodilatation had fallen out of favour as a means of treating frozen shoulders until the recent publications specifically the King’s Lynn study (Quraishi et al) in 2007. Our objective is to see if we can reproduce these results that the King’s Lynn study shows.

Method: Our study is a cohort study, prospectively evaluating the outcome of hydrodilatation as treatments for adhesive capsulitis. 24 patients were treated with hydrodilatation, and had Oxford scores done before injection; 2 months and 6 months after injection. The overall scores were recorded as was the range of movement.

Results: The overall scores for the study showed a significant improvement and increased ROM of patients’ shoulders.

Conclusion: We believe our study shows that hydrodilatation is an effective means of treating frozen shoulders. We believe our study demonstrates the need for hydrodilatation to be more widely practiced. Other therapy such as painkillers and physiotherapy has shown not to be effective, and surgery has its respective complications. Therefore hydrodilatation offers a minimally invasive, cheap, low risk alternative.


Ryan T Bicknell Matthieu César Elyès Fourati Virginie Rampal Pascal Boileau

Purpose: The objective of this study was to analyze the clinical results of arthroscopic release for the treatment of shoulder stiffness and to report the results according to etiology.

Method: Thirty cases were reviewed in 29 patients with a mean age of 48 years [range, 25–75]. The mean time from diagnosis to surgery was 37.5 months [range, 6–120]. The stiffness was considered idiopathic (i.e. frozen shoulder) (10 cases), post-traumatic (eight cases) or post-surgical (12 cases). The release consisted of 14 rotator interval resections, four anterior capsulotomies, 20 anterior and inferior capsulotomies, three tenotomies of the superior portion of the subscapularis, and 11 biceps tenotomies or tenodeses. In 26 cases, associated extra-articular procedures were also performed, including 22 subacromial bursectomies and four acromioplasties. Patients were reviewed at a mean follow-up of 44 months [range, 12–99].

Results: Eighty-nine percent were satisfied or very satisfied. The mean Subjective Shoulder Value was 76%. The mean Constant score increased from 40 ± 13 points preoperatively to 74 ± 16 points postoperatively (p< 0.05).

Conclusion: Arthroscopic shoulder release is effective for pain relief and improved function. The recovery of motion is better in idiopathic stiffness (i.e. frozen shoulder) than in post-traumatic and post-surgical stiffness. Resection of the rotator interval seems effective to restore external rotation and elevation.


Kristie D More Richard S Boorman Dianne Bryant Nicholas GH Mohtadi Preston Wiley Kelly Brett

Purpose: A major issue in the Canadian health care system are the extensive wait times for consultation with an orthopaedic surgeon. We identified that a high percentage of patients referred to shoulder surgery sub-specialists for chronic full thickness rotator cuff tears had not undergone appropriate non-operative treatment prior to being referred, and ultimately did not require surgery. In an effort to improve the referral process and to optimize patient care, we sought to identify clinical predictors for outcome of non-operative treatment of chronic full-thickness rotator cuff tears. This would allow general practitioners to clearly identify patients who are most likely to fail non-operative treatment and actually require surgical consultation. The primary purpose of this study was to determine if the outcome of non-operative treatment in chronic, symptomatic, full-thickness rotator cuff tears could be predicted based upon presenting clinical characteristics, including: age, dominant extremity involvement, gender, duration of symptoms, onset (acute or chronic), forward elevation range of motion, external rotation strength, size of tear, smoking status, and the Rotator Cuff Quality of Life Questionnaire score (RCQOL).

Method: Fifty patients, between the ages of 40 and 85 years, with a documented full-thickness tear on ultrasound or magnetic resonance imaging (MRI), were recruited prospectively. They underwent a three month home-based program of non-operative treatment under the supervision of an experienced physiotherapist and sport medicine physician. At the conclusion of the three month program, patients were evaluated by an orthopaedic surgeon and were defined as having been successful or as having failed non-operative treatment. Successful patients declined surgical treatment after consulting with the surgeon, whereas failed patients elected to undergo surgery, or, if avoiding surgery for other health or “life” reasons, had not experienced adequate improvement with the non-operative program to have been considered successful. The patient’s baseline clinical characteristics were analyzed using logistic regression to determine which characteristics were predictive of outcome.

Results: Thirty-eight of 50 (76%) of patients were successful with the non-operative program. Univariate analysis showed that a patient’s Rotator Cuff Quality of Life questionnaire score was a significant predictor of outcome of non-operative treatment (p = 0.017). Patients who were successful with non-operative treatment had a mean baseline RCQOL score of 49/100, whereas patients who failed non-operative treatment had a mean baseline RCQOL score of 31/100. The two factors of patient age and dominant extremity involvement also trended toward significance.

Conclusion: Baseline RCQOL score can predict which patients will be successful with non-operative treatment and which patients will fail non-operative treatment for a chronic, full-thickness rotator cuff tear.


Dominique M Rouleau Sylvain Gagnon Anna Potapov Fanny Canet G. Yves Laflamme

Purpose: Anatomic repair of an acute distal biceps tear has been demonstrated to improve flexion and supination strength compared with conservative treatment. The most commonly used fixation methods for a distal biceps tendon repair include suture anchors, bioabsorbable screws, and endobutton. The goal of this study was to

perform a radiologic evaluation of bioabsorbable screw tunnel osteolysis and

retrospectively review bioabsorbable-screw related clinical complications.

Method: We included twenty (20) consecutive patients who underwent primary anatomic repair of the distal biceps tendon since 2005. We used a 7x23mm biote-nodesis® screw (Arthrex) in 18 cases, and 8x23mm and 8x12mm screws in the other two cases. First, from the x-ray view done in the immediate postoperative period showing the complete screw tunnel, we measured the ratio of the volume of the bone tunnel to the volume of the radius bone section. A mathematical formula for cylindrical volume was used (¶ x r2 x h). We used a relation between two volumes rather than the tunnel volume itself for scaling purposes. Secondly, we calculated the same relation on the x-ray from the last follow-up. We then obtained the percentage of tunnel enlargement by relating the volumetric ratio from the first x-ray to the ratio from the last x-ray. Afterwards, we performed a retrospective chart review noting any bioabsorbable screw-related and postoperative complications.

Results: In the group, the average age was forty-six (46) years. All subjects were male. Eighteen (18) cases were acute complete ruptures operated in the first three weeks, one case was a partial rupture and one case was chronic (one year). The average follow up was eighteen (18) months. We found that the average initial relative volume occupied by the screw tunnel was 47 % of the bone section. At the last follow-up, this volume increased to 68%. After our chart review, we found that one patient presented with a broken screw and increased pain and that another patient developed a severe foreign-body reaction with re-rupture of the tendon requiring three reoperations.

Conclusion: The use of a bioabsorbable screw for distal biceps tendon fixation results in significant osteolysis of the radial bone at short term follow-up. Consequences of osteolysis in the radius are worrisome since iatro-genic fractures are more likely to occur. Osteolysis can be secondary to an inflammatory reaction to the screw material, bone necrosis secondary to pressure or initial thermal necrosis. We also noted two cases of severe bio-tenodesis screw-related complications among our series of twenty (20) patients. These results call into question the use of the bioabsorbable screw in distal biceps tendon repair and are important to present. Exact volume of bone loss using 3D computed tomography scan analysis as well as quality of life questionnaires and strength testing will be available for presentation.


Dominique M Rouleau Jake Kidder Juan Pons de Villanueva Savvas Dynamidis Michael De Franco Gilles Walch

Purpose: Recognition of the glenoid version is important for evaluation of different pathologies. There is no consensus on method to use to evaluate version. The purpose of this study was to compare different measurement strategies in one hundred-sixteen (116) patients with shoulder CT-scans.

Method: Scapula CT-scan axial images were revised and the cut below the base of the coracoid was selected. The glenoid version was measured according to the Friedman method (FM) and the “scapula body” methods (BM). In case of B2 glenoid three different reference lines have been measure: the neo-glenoid NG (posterior erosion surface), paleo-glenoid PG (original glenoid surface) and the intermediate-glenoid IG (line from anterior and posterior edge). Three orthopaedic surgeons independently examined the images two times and intra/inter-observer reliability was calculated using Intra-Class Correlation (ICC). The objective of this paper is to define which method shows best reliability.

Results: Group 1 (B2 excluded n=53): The average glenoid version was significantly different between two measurement techniques for all three observers, with an average of – 7.29° for BM technique and – 10.43° for FM. Intra-observer reliability was excellent for both methods (ICC: 0.958–0.979 for FM; 0.940–0.970 for BM). Inter-observer reliability was excellent for both methods (FM: ICC= 0.977; BM: ICC= 0.962). The light superiority of the first method was not significant. For group 2 – B2 glenoid (n=63): six different measures of version were taken resulting by two scapula reference line (FM and BM) and three glenoid reference line (PG, IG, NG). The average glenoid versions were significantly different (p0.82). The inter-observer reliability were also very-good or excellent for all methods (ICC > 0.79). The most reliable method for measurement of B2 glenoid version was the association of the Friedman line for the scapula axis and the intermediate glenoid line with excellent intra observer reliability (ICC > 0.957) and inter-observer reliability (ICC=0.954).

Conclusion: Measurement of glenoid version on axial cut of a Ct-scan is highly reliable. Significant differences exist between measures depending which method is used, underlying the importance of a consensus for research and clinical purpose. Despite very good performance of all methods, authors recommend the use of the Friedman method for the scapula axis reference and an intermediate glenoid line in case of B2 glenoid.


Kurt R Weiss Rej Bhumbra Wazzan Al-Juhani Anthony Griffin Benjamin Deheshi Peter Ferguson Robert Bell Jay S Wunder

Purpose: Impending and pathologic fractures of the humerus, usually due to metastatic disease, are associated with significant pain, morbidity, loss of function, and diminished quality of life. Several methods of stabilization have been described. Here we report the outcome of fixation using intramedullary poly methyl methacrylate (bone cement) and non-locking plates.

Method: A retrospective review was undertaken which included all patients treated at a tertiary musculoskeletal oncology referral center from February, 1989 to October, 2009. Patients who underwent surgical management of an impending or pathologic fracture of the humerus were included. All patients were treated using the following technique: Vascular tumors were embolized pre-operatively. Following gross tumor removal through curettage, antibiotic bone cement was placed into the humeral canal and bone defect. If there was a fracture, the bone ends were held in place as the cement cured. The humerus was stabilized using non-locking plates fixed with screws inserted through the bone and hardened bone/cement composite. Ideally, plates spanned the osseous defect by at least 2 cortical diameters and often the entire length of the bone.

Results: Clinical records were available for 67 patients who underwent the above procedure. There were 44 males and 23 females with an average age of 62.2 years. In 76% of patients there was a pathologic fracture at presentation, while in 24% it was impending. The most common histology was myeloma (21%), followed by renal (20%) and lung adenocarcinoma (20%). Forty-nine patients (73%) had one plate, 16 (24%) had two plates, one patient had three plates, and one had four plates. Complications occurred in 14 (21%) cases, and eight (12%) required reoperation of the humerus. The most common cause for reoperation was disease progression (six of eight). There were two nerve palsies, one deep infection, and one hardware failure. Interestingly, the single hardware failure occurred in a patient whose pain relief and functional status improved to the point that he fractured his construct while hammering with the affected arm in a home improvement project.

Conclusion: Intralesional tumor resection and stabilization of impending and pathologic fractures of the humerus with the described technique has several attributes. Most importantly, it provides immediate, absolute rigidity of the upper extremity and enables early pain relief and return of function without the need for osseous union. Radiation has no negative effects on the construct. The patient’s local disease burden is reduced, thus helping to alleviate tumor-related pain and slow local disease progression. Finally, this technique is user-friendly and cost-effective as it does not require any special equipment or devices that are not available to community orthopaedic surgeons. This technique provides a durable option for the treatment of impending and pathologic humerus fractures.


Anthony J Costa Satyam Patel Kishore Mulpuri Andrew Travlos Thomas J Goetz Ruth Milner

Purpose: Pinch strength has been shown to be a predictor of the ability to grip objects and perform functional hand-related tasks. As the sole flexor of the thumb IP joint, the flexor pollicus longus (FPL) muscle has previously been shown to play an essential role in directing thumb tip force as well as contribute to overall pinch strength. The relative contribution of FPL to pinch strength is unknown however. As the FPL may be affected in several acute and chronic conditions, determining the contribution of FPL to pinch strength may be useful in planning as well as evaluating treatment options. The purpose of this study was to estimate the contribution of FPL to pinch strength in-vivo using an EMG-guided, selective motor blockade, test-retest protocol.

Method: 11 healthy volunteers were recruited to participate in the study. All participants completed a brief questionnaire regarding prior hand injuries and subsequently underwent a physical examination to assess baseline hand function. Baseline pinch strength was recorded using three different pinch techniques: key pinch, 3-point chuck grasp, and tip pinch. Participants then underwent EMG-guided lidocaine blockade of the FPL muscle. Motor evoked potentials as well as skin potentials were used to confirm adequate FPL blockade. The physical exam was repeated as were pinch strength measurements. Post block splinting was necessary to stabilize the thumb IP joint. Grip strength, in addition to clinical examination, was utilized pre and post block to assess for inadvertent blockade of other muscle groups or nerves. A final clinical evaluation was conducted at study completion to note any complications or adverse effects.

Results: All three types of pinch strength showed a significant difference between pre and post measurements (p< 0.01). The mean differences pre and post were 9.7N,6.4N, and 5.2N in key, 3-point chuck, and tip pinch respectively (p< 0.01). The relative contribution of FPL for each pinch type was 53.2%,39.5%, and 44.3%. EMG, motor evoked potentials, and skin potentials confirmed adequate paralysis of the FPL. Physical examination did reveal decreased sensation in median and radial nerve distributions in some individuals, however the effect on observed motor function was negligible. Grip strength decreased by only 4N post blockade confirming no clinically significant median nerve motor blockade. The protocol was well tolerated and no serious complications were noted.

Conclusion: Using an in-vivo model we were able to estimate the contribution of FPL to overall pinch strength. In our study, FPL’s contribution to pinch strength was estimated to be 9.7N,6.4N, and 5.2N in key, 3-point chuck, and tip pinch respectively (p< 0.01). The relative contribution of FPL for each pinch type was 53.2%, 39.5%, and 44.3%. Inherent limitations in study design may have tended to overestimate the contribution of FPL to pinch. This information may be useful in planning and evaluating treatments for acute and chronic conditions affecting FPL function.


Robert KW Chan Joy MacDermid Kayvan Nateghi Ruby Grewal

Purpose: The purpose of this study was to determine the impact of an ulnar styloid fracture (USF) associated with a nonsurgically or surgically treated distal radius fracture (DRF) in adult Patients under 65 years of age.

Method: This was a cohort study involving 170 DRF patients aged 18 to 64 years old that presented to a single tertiary care center from 2004 to 2008. At initial presentation, three, six, 12 and 24 months follow up, patients were asked to complete a standardized pain and disability self-report measure, Patient Rated Wrist Evaluation (PRWE). All participants had posterior-anterior and lateral wrist radiographs performed at initial presentation and at each visit. Radiographs were reviewed at initial presentation, post treatment and at final follow up for DRF alignment as well as USF information. USFs were classified by size into tip, middle and base.

Results: There were 170 DRF patients with two patients having bilateral injuries giving a total of 172 DRFs. Age ranged from 20 to 64 years old with a mean age of 50. There were 113 females and 57 males. Eighty-four of the DRFs were not associated with an USF and 88 were. Of these 88, 42 were tip, 18 were middle and 28 were base USFs. Thirty-two of these USFs (36%) were united at final follow up. One-hundred and one patients were treated nonoperatively and 69 treated operatively for their DRFs. The PRWE scores of DRF patients with an associated USF of any size was significantly better than those without an associated USF only at 24 month follow up (10 vs. 23, p=0.04). Patients with an USF in the middle or at the base had better PRWE scores at both 12 and 24 months (17 vs. 23, p=0.05 at 12 months & 10 vs. 20, p=0.01 at 24 months). An ulnar head fracture had no influence on PRWE scores. There was no difference in PRWE scores between united and nonunited ulnar styloid fractures at all follow up time points.

Conclusion: We found that an USF was associated with better PRWE scores at 24 months and that the larger USFs, middle and base fractures, were associated with better scores at as early as 12 months. A fall onto the outstretched hand includes a component of force transmission through the ulnar side of the wrist. Without a bony ulnar styloid injury, we hypothesize that this force is transmitted through the soft tissues, creating an associated occult ligamentous, TFCC or other undetected soft tissue injuries resulting in higher pain and disability among those without a fracture. This hypothesis will require further attention in future studies. Union of the USFs also did not show an effect on outcome.


Glynn Martin Daniel Squire

Purpose: To investigate the natural history and clinical outcomes of patients suffering from various stages of Kienbock’s disease (KD) in the NL population.

Method: The present study was a retrospective analysis of 66 patients (42 male and 24 female) diagnosed with KD. Following chart reviews of these patients, a telephone interview was conducted to acquire responses to the DASH questionnaire. All analyses were performed using SPSS for Windows (version 15.0), and significance was set at P10 years). Pearson correlation was used to assess for a correlation between DASH scores and age of diagnosis as well as radiographic stage of disease. Multivariate linear regression analysis was used to account for confounding factors.

Results: The average age of diagnosis was 38.8 ±11.6 (18–70), right wrist affected in 61.5% of cases and left in 38.5%. History of trauma was present in 25 cases. With respect to radiographic stage of KD at time of diagnosis, 6 cases were in stage I, 26 in stage II, 9 in stage IIIa, 16 in stage IIIb, 5 in stage IV, and 4 with unknown stage. Forty-eight patients were treated conservatively, while 18 surgically (7 following failed conservative treatment). Thirty-nine patients provided a response to the DASH questionnaire. There was no statistically significant difference in DASH scores between any of the groups according to time since first diagnosed. There was also no significant difference in DASH scores between surgically treated and conservatively treated patients, regardless of stage of KD. Nor was there any difference in DASH scores among surgical and conservatively treated patients when individual stages of KD were considered. Furthermore, because of low numbers within each KD stage, stage III and stage IV were combined. However, once again no significant difference was found between the surgical and conservative treatment modalities. Interestingly, a positive correlation was found between age of diagnosis and DASH score (r=0.42, p=0.007). Multivariate linear regression analysis showed that the correlations remained significant after accounting for the radiographic stage of KD, gender, and time since diagnosed (p=0.02).

Conclusion: No statistically significant difference in DASH scores were found between surgically treated and conservatively treated patients in the NL population with KD regardless of stage of disease. A positive association was found between age of diagnosis of KD and DASH score, even after accounting for gender, stage of disease, and time since diagnosis. This finding suggests that those patients’ who are diagnosed and treated for KD later in life, tend not to do as well as their younger counterparts.


Rej Bhumbra Anthony Griffin Kurt R Weiss Wazzan Al-Juhani Benjamin Deheshi Jay S Wunder Peter Ferguson

Purpose: Massive endoprostheses have become the mainstay of treatment for reconstruction after resection of primary bone tumours. The Kotz Modular Femoral Tibial Replacement (KMFTR, Kotz prosthesis, Stryker Inc.) system has been one of the most widely utilized uncemented modular systems. Although this prosthesis has excellent bone ingrowth characteristics and a low aseptic loosening rate, we have identified a significant incidence of mechanical failure and breakage of the prosthesis. The purpose of this investigation is to review the outcomes after prosthetic revision for a broken Kotz prosthesis.

Method: A retrospective review was undertaken of our institutional database from the years 1989, when we first utilized the Kotz prosthesis, until present. We identified all patients who had undergone a revision of the prosthesis for mechanical failure or prosthetic breakage. Periprosthetic fractures and revisions for polyethylene bushing wear were excluded.

Results: 119 distal femoral, 55 proximal tibial and 47 proximal femoral Kotz endoprostheses (221 in total) have been implanted in our center since 1989. There were 21 revisions (9.5% of total prostheses) for mechanical failure. Of these, 16 were in the distal femur, four in the proximal tibia and one in the proximal femur. Mechanical failures occurred at a mean of 77 months (range 24–170). Of the 21 metal failures, 8 stems broke at the junction of the stem and body, 8 fractured through screw holes in the stem, 3 fractured the derotation lug, one fractured the tibial housing and one lateral side-plate failed. Of these failures only three implants had associated definite loosening and two of these three were cemented. Broken stems initially required extraction whilst preserving as much of the longitudinal and transverse bone stock as possible in order to facilitate osseo-mechanical integration of the revision prosthesis. This was accomplished using trephines to core the ingrown broken stem out of the bone. Over the last 20 years, the 16 broken stems have been revised in 5 patients to larger Kotz uncemented stems, 2 to cemented GMRS stems with an adaptor to the KMFTR system, 3 to Restoration uncemented revision hip stems with a custom adaptor to the KMFTR system, 2 to custom GMRS uncemented stems with an adaptor to the KMFTR system, and 4 to total femurs. All except one patient was alive with no evidence of disease. Post-revision, 14 patients had TESS, MSTS87, MSTS93 scores of 80.5, 25.5 and 70 respectively.

Conclusion: Despite very low aseptic loosening rates, mechanical failure of the Kotz prosthesis continues to be a significant clinical problem even several years after implantation. Fatigue failure often leads to the difficult scenario of removing a well-ingrown uncemented stem. Our data illustrates that these prostheses can often be successfully revised by trephining out the broken stem and inserting new uncemented stems. Functional outcome continues to be good and is comparable to pre-revision levels.


Francesco Pegreffi Lorenza Belletti Marco Esposito

Purpose: The purpose of this study was to evaluate the long-term results of arthroscopic treatment in patients affected by triangular fibrocartilage complex (TFCC) type 1b lesions associated with distal radio ulnar joint (DRUJ) instability.

Method: 138 patients affected by TFCC type 1b lesions: Group A (117 patients, 27±7 yrs) were treated using an out-in arthroscopic technique and Group B (21 patients, 24±4 yrs) with an associated total DRUJ instability, were treated using an out-in arthroscopic technique in addition to an anchor placement. Inclusion criteria were: TFCC tears, type 1b lesions and no previous wrist fractures. SF-36, DASH, VAS, and ROM were accessed preoperatively and at four years follow-up.

Results: All the patients have a significant improvement in terms of SF-36 (p0.05).

Conclusion: Arthroscopy is a tool of paramount importance in both diagnosis and treatment of TFCC injuries even associated with DRUJ. Furthermore, type 1b lesions associated with total DRUJ instability should be managed combining an out-in arthroscopic technique with the use of an anchor to completely relieve pain and restore wrist function.


David Pichora Burton Ma Manuela Kunz Hisham Alsanawi John Rudan

Purpose: We compare the accuracy and precision of patient-specific plastic guides versus computer-assisted navigation for distal radius osteotomy (DRO). We hypothesize that guides would provide similar accuracy and precision compared to computer-assisted surgery, and that they would be faster to use than navigated surgery.

Method: We used CT scans, computer models, and planned corrections of radii from seven patients who had previously received computer-assisted DRO. The planned correction included the locations and directions of the screw holes for the fixation plate on the intact deformed radius. Using computer-assisted technique, the surgeon drills the holes for the fixation plate using computer navigation before performing the osteotomy; after cutting the radius, the plate is fixated to the distal radius, and the distal radius is distracted until the holes in the proximal radius align with the holes of the fixation plate. A patient-specific guide can be manufactured that fits on the intact deformed radius to guide the drilling of the screw holes. The guide is designed so that it mates exactly with the dorsal surface of the radius. Each guide was designed using custom software and manufactured in ABS plastic using a 3D printer. The surgeon places the guide on the radius and uses a metal drill sleeve in each guide hole to guide the drilling of the plate screw holes. We manufactured urethane plastic phantoms of the seven deformed radii. Our laboratory experiment had six surgeons each perform four computer-assisted and four patient-specific guide procedures on the phantom radii; the specimen and type of guidance were randomly chosen. The time from the start of the procedure to when the shaping of the distal radius was completed was recorded; we did not record the time required to cut and fixate the radius because this time does not depend on the type of guidance used. The plated phantoms were assessed for errors in ulnar variance, radial inclination, and volar tilt as compared to the planned correction.

Results: The results for the computer-assisted procedures were: ulnar variance error (−0.2 +/ − 2.0 mm), radial inclination error (−0.9 +/ − 6.1 deg), volar tilt error (−0.9 +/ − 1.9 deg). The results for the customized jig procedures were: ulnar variance error (−0.7 +/ − 0.6 mm), radial inclination error (−1.0 +/ − 1.4 deg), volar tilt error (−0.4 +/ − 2.2 deg). There were no significant differences detected in the means of the measurements (significance level 0.05) using the two-sample t-test. Significant differences were detected in the variances of the ulnar variance and radial inclination errors (significance level 0.05) using Levene’s test. It took (705 +/ − 144 sec) to perform the computer-assisted procedures and (214 +/ − 98 sec) to perform the customized guide procedures. The differences between the means and variances were statistically significant.

Conclusion: Patient-specific guides are as accurate, more precise, and require less time than computer-assisted navigation for DRO.


Paul W Clarkson Anna Thompson Amy E Phillips Torsten O Nielsen Don Wilson Lorna Weir Rona Cheifetz Karen Goddard

Purpose: To determine whether combined modality Positron Emission Tomography and Computed Tomography (PET-CT) imaging can pre-operatively identify de-differentiated areas within well-differentiated liposarcomas/ atypical lipomatous neoplasms. Well-differentiated lipo-sarcomas show a reasonably homogeneous lesion with fat signal characteristics on MRI and are managed with surgical excision or regular observation. They can recur locally, but never metastasize. Up to 5% of well-differentiated liposarcomas will contain a de-differentiated component that is not apparent on MRI. When present, this de-differentiated component carries a much worse prognosis and requires more aggressive local management. Currently this is only identified after surgical resection. Pre-operative identification of a de-differentiated component within the lesion by PET-CT would allow for better treatment planning. However, PET-CT is an expensive investigation and has not been reported in this application before, although it has been used for imaging of soft tissue tumours.

Method: We have prospectively enrolled 40 subjects into this study. Eligible subjects presented with a > 8cm and deep well-differentiated liposarcoma in the extremities or retroperitoneum, which was confirmed by MRI. Subjects underwent a pre-operative PET-CT scan to look for areas of de-differentiation within the lesion. The PET-CT results were compared to the final pathological analysis of the surgical specimen. When necessary for diagnostic purposes, cytogenetic analysis was also completed.

Results: Thirty-one of the 40 subjects enrolled have had PET-CT scan and surgery. Seven subjects are waiting for PET-CT and surgery by December 2009. Two subjects were withdrawn from the study: one because the PET-CT scan could not be scheduled prior to surgery, and one because the subject ultimately declined surgery. Of the 31 lesions excised, 2 contained de-differentiated areas within the lesion. The PET-CT detected a small area of low to moderate FDG uptake (thigh lesion, max Standard Uptake Value (SUV) 3.6) for one of these patients; however no uptake on PET-CT was seen for the other (retroperitoneal lesion, max SUV 1.7).

Conclusion: PET-CT does not appear to reliably detect de-differentiated areas within well-differentiated lipo-sarcomas. Our data does not support the use of PET-CT for this purpose as it may be misleading and wasteful of resources.


Daniel Friedmann Ashley Gefen Robert E Turcotte Jay S Wunder David Roberge Peter Ferguson Brian O’Sullivan Charles Catton Carolyn Freeman Benjamin Deheshi Anthony Griffin Soha Riad Cindy Wong

Purpose: Lymphoedema is a serious potential complication of the management of extremity soft tissue sarcoma (STS) about which relatively little is known. We aimed to evaluate the incidence of lymphoedema, its severity and associated risk factors following limb salvage for extremity STS.

Method: Lymphoedema severity (EORTC/RTOG) was recorded prospectively in two databases of soft tissue sarcoma patients. Patient’s demographics, tumor characteristics, surgical procedures, radiotherapy dosage, complications and functional outcomes (MSTS, TESS) were also prospectively collected. Charts were also retrospectively abstracted for body mass index (BMI) and medical comorbidities.

Results: 289 patients had sufficient data for analysis (158 male). Mean age was 53 (range 16–88). Mean BMI was 27.4 (range: 15.8–52.1). 209 had lower extremity tumors and 80, upper. Mean tumor size was 8.1 cm (range 1.0–35.6 cm). 77 had no adjuvant radiation, 180 had 50 Gy and 32, 66 Gy. The incidence of lymphoedema was found to be 28.7% (58 mild, 22 moderate, 3 severe). Mean MSTS score was 32 (range: 11–35) and TESS was 89.4 (range: 32.4–100). We grouped cases with lymphoedema grade 0–1 and 2–3. Univariate analysis found significant correlations between the severity of lymphedema and tumor size ≥5 cm (p=0.011), deep location (no patient with a superficial tumor had severe lymphoedema, p=0.001), and radiation dosage 50 vs 66 Gy (p=0.021) but not between upper vs lower extremity (p=0.06).

Conclusion: 9% of STS studied developped significant post-treatment lymphoedema. Large, deep tumors and necessity for 66 Gys were most at risk. This group could be targeted for prophylatic intervention.


Paul RT Kuzyk Radovan Zdero Suraj Shah Michael Olsen James P Waddell Emil H Schemitsch

Purpose: Minimizing tip-apex distance (TAD) has been shown to reduce clinical failure of extramedullary sliding hip screws used to fix peritrochanteric fractures. There is debate regarding the optimal position of the lag screw in the femoral head when a cephalomedullary nail is used to treat a peritrochanteric fracture. Some authors suggest the TAD should be minimized as with an extramedullary sliding hip screw, while others suggest the lag screw should be placed inferior within the femoral head. The primary goal of this study was to determine which of 5 possible lag screw positions in the femoral head provides greatest mechanical stiffness and/or load-to-failure for an unstable peritrochanteric fracture treated with a cepha-clomedullary nail. The secondary goal was to determine if there is a linear correlation between implant-femur mechanical stiffness and/or load to failure (dependent variables) with a series of five radiographic measurements (independent variables) of distance from the lag screw tip to the femoral head apex.

Method: Long Gamma 3 Nails (Stryker, Mahwah, NJ) were inserted into 30 left synthetic femurs (Pacific Research Laboratories, Vashon, WA). An unstable four-part fracture was created, anatomically reduced, and repaired using one of 5 lag screw placements in the femoral head:

superior (n=6),

inferior (n=6),

anterior (n=6),

posterior (n=6),

central (n=6).

All specimens were radiographed in the anterioposterior and lateral planes, and radiographic measurements including TAD and a calcar referenced tip-apex distance (CalTAD) were calculated. All specimens were tested for axial, lateral, and torsional stiffness, and then loaded-to-failure in the axial position using an Instron 8874 (Canton, MA). ANOVA was used to compare means of the five treatment groups. Linear regression analysis was used to compare stiffness and load-to-failure (dependant variables) with radiographic measurements (independent variables). A post hoc power analysis was performed.

Results: The inferior lag screw position had significantly greater mean axial stiffness than superior (p< 0.01), anterior (p=0.02) and posterior (p=0.04) positions. Analysis revealed significantly less mean torsional stiffness for the superior lag screw position compared to other lag screw positions (p< 0.01 all 4 pairings). No statistical differences were noted for lateral stiffness. Superior and central lag screw positions had significantly greater mean load-to-failure than anterior (p< 0.01 and p=0.02) and posterior (p< 0.01 and p=0.05) positions.

There were significant negative linear correlations between stiffness tests with CalTAD, and load-to-failure with TAD. Power was greater than 95% for axial stiffness, torsional stiffness and load-to-failure tests.

Conclusion: Position of the lag screw in the femoral head affects the biomechanical properties of the implant-femur construct. Central placement of the lag screw with minimization of TAD may provide the best combination of stiffness and load-to-failure.


Peter Ferguson Cara Emelia Fallis Anthony Michael Griffin Benjamin Deheshi Jay S Wunder

Purpose: Patients are often referred to tertiary care centers after unplanned excision of soft tissue sarcomas. In situations where the tumour is small and superficial, the situation can often easily be salvaged by re-excision of the tumour bed. However, if the original tumour is large, deep to fascia or directly adjacent to bone or neurovascular structures, the salvage procedure often becomes more complex and morbid. The purpose of this study is to evaluate the effect of unplanned excision of “high-risk” soft tissue sarcomas on patient outcome.

Method: We reviewed our prospectively collected sarcoma database from 1989 to 2006. Patients who underwent definitive resection of a soft tissue sarcoma at our centre were included. Patients were divided into 2 groups based on whether or not they had undergone initial unplanned resection of their tumour prior to referral to our centre for definitive management. Low risk patients who had tumours that were less than 5 cm in diameter, superficial to fascia, and not overlying bone or neurovascular structures were excluded.

Results: A total of 1034 patients met inclusion criteria. Of these, 385 (37%) patients had undergone an unplanned excision prior to referral, while 649 (63%) patients were referred to our centre with an intact tumour without prior unplanned excision. There was a higher percentage of high grade (61% vs. 50%) and deep tumours (88% vs. 65%) in the unplanned excision group, but the mean tumour diameter was smaller in the unplanned excision group (5.9 cm) compared to the control group (10.6 cm). There was no difference between the groups in terms of rate of amputation, necessity for flaps for coverage, and local recurrence-free survival. Complications were more common in the control group (34%) than the unplanned excision group (20%, p< 0.0005, Chi-square). 5-year overall (p< 0.00005, log rank) and metastasis-free (p< 0.00005, log rank) survival were higher in the unplanned excision group. There was no difference in TESS, MSTS87 or MSTS93 functional outcome scores between the groups.

Conclusion: Patients referred to a tertiary sarcoma centre after unplanned resection of a soft tissue sarcoma can still be salvaged with appropriate multidisciplinary care. Patients referred after unplanned excision appear to fare at least as well as those initially resected at our centre, and fare better in terms of some outcomes studied. The majority of this difference can likely be explained by significant differences in important prognostic factors such as grade, size and depth between the unplanned excision group and control group initially managed at our centre. Patients referred after unplanned excisions appear not to have as dismal an outcome as has been previously reported.


James P Waddell Janet McMullan Rhona McGlasson Nizar N Mahomed John Flannery

Purpose: Fractures of the proximal femur are increasing in incidence as the population ages. In order to address this problem the Province of Ontario, Canada (population 14 million) has advocated an integrated model of care.

Method: A policy to improve the outcome for patients sustaining hip fractures has been developed. It has been implemented in the 14 health regions of the province. The objectives are:

All surgical procedures to be performed within 48 hours of patient’s admission to hospital.

Surgical treatment of hip fractures must permit unrestricted weight bearing.

A structured acute care post-operative course followed by admission to progressive rehabilitation.

Results: Since the implementation of this policy 90% of all hip fracture patients are receiving definitive surgical treatment within 48 hours of admission. Site variations are identified and remedial actions implemented for those hospitals which fail to meet this target. Acute care length of stay following hip fracture has declined from a mean of 17 days to a mean of 8 days. The number of patients with hip fractures returning to their pre-injury residence has increased significantly from approximately 35% to 70% at 3 months post-fracture.

Conclusion: A structured program for hip fracture care can be developed in large population areas and has been implemented for the approximate 10,000 patients sustaining hip fractures annually within our jurisdiction. This model should be broadly applicable to other health regions.


Mohit Bhandari Alicja Bojan Carl Eckholm Ole Brink Anthony Adili Sheila Sprague Nasir Hussain Anders Joensson

Purpose: The popularity of intramedullary nails (IMN) for trochanteric hip fractures has grown substantially with little supportive evidence that IMN are superior to conventional sliding hip screws (SHS). We aimed to assess the impact of SHS or IMN intramedullary nailing on functional outcomes and rates of re-operation in elderly patients with fractures.

Method: We conducted a multi-center, pilot randomized trial including three clinical sites across Sweden, Denmark, and Canada. We randomized 85 elderly patients with stable and unstable trochanteric hip fractures to either SHS or an IMN. The primary outcome, revision surgery, was independently adjudicated at one year. Secondary functional outcomes included the Parker Mobility Score (PMS), the Merle D’Aubigne Score, the Short Form-12 (SF-12) and the Euroquol-5D.

Results: Eighty five patients were enrolled. Fifteen patients died prior to the one year follow up. Across treatment groups, patients did not differ in age, gender and fracture type. The overall revision risk was 11.6% (8/69) and did not differ significantly between groups (IMN: 5; SHS: 3). Patients treated with IMN had significantly higher Merle D’Aubigne function subscores at 6 (p=0.01) and 12 months (p=0.05). Gamma3 nails approached significantly higher scores in the Parker mobility score at 6 (p=0.08) and 12 months (p=0.056). Non-significant differences were identified in the SF-12 and Euroquol-5D quality of life measures; however, in both scores, the Gamma3 nailed trended to higher scores than the sliding hip screw.

Conclusion: Our findings of early functional gains without increased risk of revision surgery support the increased popularity of IMN for the management of trochanteric hip fractures in elderly patients.


Nicole Simunovic

Purpose: The purpose of this study was to evaluate how outcome assessment committees of various sizes, and the biases and personalities of its members, potentially impact a trial’s results.

Method: We conducted a retrospective analysis of the available individual and consensus data from an adjudication committee in a multinational trial (the SPRINT trial) of fracture fixation alternatives. The trial committee members included six members (5 surgeons, 1 methodologist) who independently determined the outcome of reoperation, and any discordant cases were discussed in the committee until a consensus was achieved. We described the pattern of agreement among adjudicators, modeled the adjudication process, and predicted the results if a smaller committee had been used. We also tested for adjudicator biases based upon their preferences for reamed or unreamed intramedullary nails, the presence of a potentially dominant adjudicator, and evaluated the resource implications of reducing the size of an adjudication committee.

Results: Overall, committee member agreement was moderate (Kappa Free=0.6). We found that reducing the number of adjudicators from six to three would have changed the consensus outcome in less than 15% of cases. Regardless of committee size, per-patient analyses also demonstrated very little change in the final study results across all fracture types or in the open fracture subgroup. Results from the original SPRINT adjudication indicated a significant decrease in the rate of reoperations associated with reamed intramedullary nailing among patients with closed fractures (relative risk 0.65; 95% confidence interval 0.46 to 0.93; p=0.02). Under the model, in committee sizes of three or less persons, these estimates of treatment effect were no longer significant. There was a significant difference between adjudicators with respect to the number of times their independent decision was in the minority but nevertheless became the final consensus decision (p=0.046), suggesting a dominant adjudicator was present in the committee. There were large predicted savings in cost and time with a reduced committee size.

Conclusion: In this study, smaller committees (i.e., four or five rather than six adjudicators) would likely have produced similar results, substantially reducing costs of research.


Paul RT Kuzyk Radovan Zdero Suraj Shah Michael Olsen James P Waddell Emil H Schemitsch

Purpose: Cephalomedullary nails rely on a large lag screw that provides fixation into the femoral head. There is an option to statically lock the lag screw (static mode) or to allow the lag screw to move within the nail to compress the intertrochanteric fracture (dynamic mode). The purpose of this study was to compare the biomechanical stiffness of static and dynamic modes for a cephalomedullary nail used to fix an unstable peritrochanteric fracture.

Method: Thirty intact synthetic femur specimens (Model #3406, Pacific Research Laboratories, Vashon, WA) were potted into cement blocks distally for testing on an Instron 8874 (Instron, Canton, MA). A long cephalomedullary nail (Long Gamma 3 Nail, Stryker, Mahwah, NJ) was then inserted into each of the femurs. An unstable four-part fracture was created, anatomically reduced, and the cephallomedullary nail was reinserted. Mechanical tests were conducted for axial, lateral, and torsional stiffness with the lag screws in:

static and

dynamic modes.

A paired student’s t test was used to compare the 2 modes.

Results: The axial stiffness of the cephalomedullary nail was significantly greater (p< 0.01) in the static mode (484.3±80.2N/mm) than in the dynamic mode (424.1±78.0N/mm) (Fig.2A). Similarly, the lateral bending stiffness of the nail was significantly greater (p< 0.01) in the static mode (113.9±8.4N/mm) than in the dynamic mode (109.5±8.8N/mm). The torsional stiffness of the nail was significantly greater (p=0.02) in the dynamic mode (114.5±28.2N/mm) than in the static mode (111.7±27.0N/mm).

A post hoc power analysis with & #945;=0.05 and & #946;=0.20 revealed that the paired t test on 30 samples was sufficiently powered to determine a difference in mean axial stiffness of 33.0N/mm (6.8% of static stiffness), a difference in mean lateral bending stiffness of 3.6N/mm (3.2% of static stiffness) and a difference in mean torsional stiffness of 3.4N/mm (3.0% of static stiffness).

Conclusion: Our results show that there is a 60N/mm reduction in axial stiffness of the cephalomedullary nail when the lag screw is changed from static to dynamic mode. This represents a 12.4% reduction in axial stiffness with a change from axial to dynamic modes which may be clinically significant. The differences in lateral (4.4N/mm, 3.9%) and torsional (2.8N/mm, 2.4%) are small enough that they are likely not clinically significant. We felt that a difference of greater than 10% in axial stiffness and a difference of greater than 5% in lateral or torsional stiffness would be clinically significant. Our study was adequately powered to detect these differences. Given the significant reduction in axial stiffness with dynamization of the cephalomedullary nail construct, we recommend use of the static mode when treating unstable peritrochanteric fractures with a cephalomedullary nail.


Brad Petrisor

Purpose: The optimal choice of irrigating solution or irrigating pressure in the initial management of open fracture wounds remains controversial. FLOW compared the effect of castile soap versus normal saline, and low versus high pressure pulsatile lavage on one year re-operation rates in patients with open fracture wounds.

Method: We conducted a multicenter, blinded, two-by-two factorial, pilot randomized trial of 111 patients with open fracture wounds receiving either castile soap solution or normal saline and either high or low pressure pulsatile lavage. The primary outcome, reoperation within one year, included infections, wound healing problems, and nonunions. Secondary outcomes included all operative and non-operative infections, wound healing problems, nonunion and functional outcomes. We followed the intention to treat principle.

Results: Eighty-nine patients (80.2%) completed the 12-month follow-up. As anticipated in this small-sample-size pilot study, results were compatible with substantial benefit and substantial harm: the hazard ratio (HR) for reoperation with castile soap was 0.77, 95% CI 0.35 to 1.69, p=0.52; with low pressure lavage, the hazard ratio for the risk of reoperation was 0.56, 95% CI 0.25 to 1.27, p=0.17. Secondary outcomes showed a significant relative risk reduction for nonunion of 63% in favour of castile soap (p=0.036), and a trend for a relative risk reduction for nonunion of 44% in favour of low pressure lavage (p=0.22).

Conclusion: The FLOW pilot study suggests the possibility of an important reduction in reoperation rates for both castile soap and low pressure pulsatile lavage. Our findings provide compelling rationale for continued investigation in a pivotal FLOW trial of 2280 patients.


Ross K Leighton Abdullah A Hawsawi Allun Evans Kelly Trask Richard A Preiss

Purpose: surgical fixation distal femoral fractures has been associated withnonunion and varus collapse. the soft tissue stripping esulted from this fracture and caused by the surgical approach have been factorassociated with delayed union and infection. the limited soft tissue exposure has been lauded as a solution to this fracture. however, it has occurred with new fixation as well (locked plate) this study is an attempt to look at the fixation from the surgical approach prospective. does the liss system improve the results of this difficult fracture? is there truly a difference in the outcome of this fracture utilizing the locked plate system or the percieved difference due to surgical mini invasive approach.

Method: one hundred and forty patientswere screened, and only 53 were randomized and treated in six academic centers over five years. all c3 fractures were excluded from the study as they were felt not to be treatable by the dcs device, but they were treated and fixed appropiately. thirty five females and 18 males were included and appropiately randomized.

Results: fifty three patients were randomized, 28 had the liss implant while 25 had the dcs utilized. there were three nonunions in the liss group, plus two patients required an early reoperation in the early post operative periods ( second – fifth post op. day) due to an early loss of reduction. further more, one patient developed a knee arthrofibrosis that required arthroscopic joint release with subsequent implant failure. that necessiated a reoperation. in the dcs group there was only one nonunion, that required reoperation. this translated into reoperation rate of 21%in the liss group compared to 4% with dcs.

Conclusion: this prospective multicenter randomized trial showeda significant difference when comparing the liss device to the dcs system in minimal invasive approach of distal femoral fractures fixation


John Antoniou Alain Petit Fackson Mwale David J Zukor Olga L Huk

Purpose: Several studies have shown elevated levels of metal ions in blood of patients with metal-on-metal (MM) total hip arthroplasty (THA). To minimize wear, the elastohydrodynamic theory suggests wear reduction for larger diameter head bearings. This significant reduction in wear has been demonstrated in hip simulators for the 36 mm-head compared to the 28 mm-head prosthesis. However, the survival of larger head MM THAs and the levels of metal ions in the blood of patients having these implants are still to be determined.

Method: Fifty (50) patients (56 hips) who received a DePuy Ultamet™ MM hip bearing (40/44 mm-head) at our Institution between July 1st 2007 and August 31st 2008 were included in the study. Clinical and radiologic data were collected pre-operatively as well as at 6–8 weeks, 4–6 months, and 1 year postoperatively. Results were compared to those of subjects (65 patients, 71 hips) who received a 36 mm-head prosthesis. Cobalt (Co) and chromium (Cr) concentrations were measured at 1 year post-operatively in the blood of patients by ICP-MS. Since Co and Cr ions have the potential to induce irreversible biochemical damage to macromolecules, the levels of oxidative stress markers (total antioxidants and lipid peroxides) were measured in the plasma of these patients.

Results: At their 1-year post-operatively follow-ups, all patients were doing well and no sign of osteolysis was observed on X-rays. Harris Hip Score increased in both groups with a tendency to higher score in the 40–44 mm group compared to the 36 mm group. Activity score also increased in both groups after 1 year without statistical significant differences. Results also show that the levels of Co and Cr ions increased significantly in both groups compared to the Pre-OP control group. The levels of Co were also significantly higher in patients with large head arthroplasty (40 and 44 mm-head) compared to those of the 36 mm-head group (p=0.012). The levels of Cr were similar in both the large head and the 36 mm-head group (p=0.41). Finally, results show that there were no differences in the levels of total antioxidants and peroxides between the 40–44 mm group and the 36 mm group. Moreover, there was no increase in the level of these markers of oxidative stress compared to the Pre-OP control group.

Conclusion: The present study shows that at 1-year postoperatively, patients with large 40–44 mm-head THA had comparable clinical outcomes than those with 36 mm-head prosthesis. However, the levels of Co ions were significantly higher in these patients compared to patients with 36 mm-head THA. This suggests a higher health risk for these patients due to the presence of these ions. However, there were no effects on the levels of oxidative stress markers in the blood of these patients, suggesting that there is no increased risk at short-term. In conclusion, due to the high level of Co ions, longer follow-ups are required to conclusively determine the outcomes of the patients and the survivorship of these new bearings.


Mohit Bhandari Bauke W Kooistra Jason Busse Stephen D Walter Paul Tornetta Emil H Schemitsch

Purpose: We aimed to preliminarily validate a newly developed system, the radiographic union scale for tibial (RUST) fracture healing. We hypothesized that RUST would demonstrate better inter-rater reliability than assessment of the number of cortices bridged and correlate with functional outcomes at least as strongly as surgeon’s assessment of cortical bridging.

Method: Three blinded orthopaedic trauma surgeons independently assigned a RUST score and a number of cortices bridged by callus (zero to four) to each set of AP and lateral radiographs at each follow up period. RUST is scored from four (definitely not healed) to 12 (definitely healed) based on the presence or absence of callus and of a visible fracture line at the total of four cortices visible.

Results: For 549 sets of reviewed radiographs, inter-rater reliability for RUST scores were found to be substantially higher than for assessment of the number of cortices bridged (intra-class correlation coefficient=0.84; 95% CI, 0.80–0.87 versus kappa = 0.73; 95% CI, 0.64 – 0.81, respectively). Both methods of assessing radiographic healing were strongly correlated with weight-bearing status (r and ρ> 0.50), moderately correlated with patient-reported functional recovery and the SF-36 Physical Functioning component scores (r and ρ> 0.30), and minimally correlated with HUI Mark II scores, return to work, and the SF-36 Role Physical component and Physical Component Summary scores (r and ρ> 0.10). Neither assessment was correlated with patient-reported pain scores. All correlations were similar for RUST and the number of cortices bridged.

Conclusion: This study provides preliminary evidence that RUST can be used as a valid and reliable alternative assessment of tibial fracture healing.


Anthony Marchie Mark Callanan Charles Bragdon David Zurakowski Henrik Malchau

Purpose: The purpose of this study was to determine if correlation exists between acetabular cup positioning and factors relating to the surgeon and patient.

Method: Data for 2063 patients who underwent primary or revision THA from 2004 – 2008 were compiled. The post-op anteroposterior (AP) and cross-table lateral digital radiographs for each patient were obtained. The AP radiograph was measured using Hip Analysis Suite to calculate the cup abduction and version angles (version direction determined separately). Acceptable ranges were 35–45° for abduction, and 5–20° for version. Correlations were then determined with SPSS™ software.

Results: There were 1980(96%) qualifying patients. There were 1025(52%) acetabular cups that fell within the 35–45° abduction range, and 1287(70%) cups in the 5–20° version range. Regression analysis showed that the only independent predictor of acceptable abduction angle was the surgical approach (p< 0.001). Posterolateral approach was the most accurate (57% acceptability). In contrast to the posterolateral, the MIS (2 incision) approach was 3 times (95%C.I. 1.5–5, p=0.001), and the mini anterolateral approach 2.5 times (95%C.I. 1–6.5, p=0.035) more likely to have unacceptable abduction angles. The only independent predictor of acceptable version was the performing surgeon (p< 0.001), with higher volume surgeons showing greater accuracy.

Conclusion: The posterolateral approach was superior to MIS (2 incision) and mini anterolateral approaches for acceptable abduction angle, and surgeon volume influenced version angle acceptability. Further analysis on variables and their influence on cup position at a lower volume medical center would provide a valuable comparison.


D Gordon Allan Lucas Rylander Joseph C. Milbrandt Adam Wallace

Purpose: Metal-on-Metal (MOM) hip resurfacing is a popular alternative to conventional hip arthroplasty. The purpose of the present study is to compare patient characteristics and radiographic findings for revision versus non-revision cases treated at a single center with a MOM resurfacing device.

Method: Eighty-nine MOM resurfacing arthroplasties were performed between December 2001 and June 2006. Subjects were assessed for implant revision status, age, gender, weight, operative side, primary diagnosis, femoral head size, and time to revision. Postoperative radiographs were assessed for acetabular cup inclination and femoral stem inclination relative to the femoral neck.

Results: Thirteen of 89 hips (14.6%) have required revision to date with follow-up ranging from 4 (a revision) to 91 months. Female gender, smaller implant size, and a diagnosis of osteonecrosis were all associated with lower device survival. A significant difference in acetabular cup angle was observed between revised and non-revised hips. However, this difference can largely be attributed to two outliers in cup position associated with early migration and the difference became non-significant when these outliers were excluded. No significant difference was found in stem angle between revised and non-revised hips. The revision rate for the first 25 hips was 24% versus 8% for the next 64 hips. Females accounted for 56% of subjects 1–25 and 23% of subjects 26–89. Seven of the 8 failures for the first 25 procedures occurred beyond 4 years follow-up. Only 2 early device failures (< 2 yrs) were identified and both were in the 26–89 subgroup.

Conclusion: Despite representing only 33% of included subjects, females accounted for 62% of revision procedures. An apparent learning curve was identified by a lower device survival proportion for the first 25 hips versus hips 26–89. However, this learning curve was not associated with failures which could be attributed to acetabular or femoral component malpositioning and is likely explained by the higher proportion of females enrolled early in the study. Taken together, we propose the apparent “learning curve” exhibited in our study is not wholly technical in nature but rather influenced by changes in patient selection over time by the operative surgeon.


Paul E Beaulé Kamal Banga

Purpose: The surgical correction of FAI deformity is a well accepted treatment in patients presenting with hip pain with associated labral-chondral damage. The anterior approach with assisted hip arthroscopy provides access to the anterior head-neck junction with potentially quicker recovery for patients. The purpose of this study is to present the safety and efficacy of this approach in performing impingement surgery.

Method: Forty-eight Hueter procedures were performed in 45 patients (13 males and 32 females). Mean age was 42.09 years (range, 21–65 years), and mean BMI was 24.31(range, 21–33). The scope was performed first to deal with intra-articular damage. All patients were diagnosed with CAM type FAI with labral pathology based on MRI arthrogram with an alpha angle > 50.5 degrees.

Results: At a mean follow-up of 21.8 months (range 12–30 months), Harris Hip scores improved from 64.66 (range, 42.0–93.0) to 79.97 (range, 47.0–96.0). There were 5 re-operations at a mean time of 15.2 months (range, 4–22). One had a repeat hip scope for intra-articular adhesions, and another for recurrent traumatic tear of the labrum. Three cases with residual hip dysplasia had corrective surgery with a peri-acetabular osteotomy at an average of 16.67 months (range, 15–18 months).

Conclusion: Overall, we have found this to be a reliable, safe and reproducible approach to the treatment of FAI. This is a day care procedure as compared to the classic open procedure. Uncorrected hip dysplasia in the presence of a CAM deformity is a risk factor for early failure.


Emil H Schemitsch Jonathan Lescheid Radovan Zdero Suraj Shah Paul RT Kuzyk

Purpose: Optimal fixation for comminuted proximal humerus fractures is controversial. Complications using locked plates have been addressed by anatomic reduction or medial cortical support. The current study measured relative mechanical contributions of varus malalignment and medial cortical support.

Method: Forty synthetic humeri were divided into three groups, osteotomized, and fixed at 0, 10, and 20 degrees of varus malreduction with locked proximal humerus plates (AxSOS, Global model, Stryker, Mahwah, NJ, USA). This simulated mechanical medial support with the cortex intact. Axial, torsional, and shear stiffness were experimentally measured. Half of the specimens in each of the groups underwent a second osteotomy to create a segmental defect which simulated loss of medial support with the cortex removed. Axial, torsional, and shear stiffness experiments were repeated, followed by shear load to failure in 20 degrees of abduction.

Results: For isolated malreduction with the cortex intact, the repair construct at 0 degrees showed statistically equivalent or higher axial, torsional, and shear stiffness than other groups assessed. Subsequent removal of cortical support in half the specimens resulted in a drastic effect on axial, torsional, and shear stiffness at all varus angles. Repair constructs with the cortex intact at 0 and 10 degrees resulted in mean shear failure forces of 12965.4 N and 9341.1 N, respectively. These were statistically higher (p< 0.05) compared to most other groups tested. Specimens failed mainly by plate bending as the femoral head was pushed down medially and distally.

Conclusion: Anatomic reduction with the medial cortex intact was the stiffest construct after a simulated two-part fracture. This study also supports the practice of achieving medial cortical support by fixing proximal humeral fractures in varus if necessary. This may be preferable to fixing the fracture in anatomic alignment when there is a medial fracture gap.


Ross K Leighton Kelly Trask Gwendolyn Dobbin

Purpose: The ideal bearing surface for total hip arthroplasty is still an area of debate. Increasing numbers of total hip replacements are being done in the younger patient population. Ceramic-on-ceramic bearings have gained popularity due to their low wear rate; however, ceramic fractures with subsequent catastrophic failures have been reported and squeaking of ceramic hips is an emerging problem. This study reports on early results of ceramic-on-ceramic total hip replacements.

Method: This is a study analyzing prospectively collected data for 120 alumina-on-alumina total hip replacements with minimum follow up of 24 months. Average age at time of surgery was 49 years. The main outcome of the study was to identify complications related to the pros-theses. Standard outcome measures (SF-12, Harris Hip Score, and WOMAC) were also collected at clinic visits.

Results: All patients received either a Stryker Trident acetabular cup with Secure-fit Plus stem or Depuy Pinnacle cup with an AML stem. Average follow-up was five years (range: two – nine years). No revisions were performed for loosening or catastrophic failures. No wear, loosening, or osteolysis was seen on radiographs. The SF-12, WOMAC, and Harris Hip scores were not significantly different from other reported hip series. The most common complication has been the “squeaking” hip. To date we have had six squeaky hips in our centre, three of which have been revised. All the squeaking hips received the Trident acetabular cup (Stryker) which has a circumferential metal lip to protect the ceramic bearing. This metal flange can affect range of motion and predispose patients to earlier impingement (particularly if a minus 3 head is utilized). One patient with a Depuy hip complains of intermittent pain and radiographs show some fragmentation, but the hip has not been revised.

Conclusion: Ceramic-on-ceramic bearing surfaces in total hip arthroplasty may provide a more durable prosthesis with outcomes similar to standard THA, especially in young and active patients; however, caution should be used if considering the Stryker Trident shell due to the large number of “squeaky hips”.


Sanket Diwanji Jean-Michel Laffosse Kim Aubin Martin Lavigne Pascal-André Vendittoli

Purpose: Femoral neck narrowing (FNN) has been reported after metal-on-metal hip resurfacing (HR). It is significant (> 10%) in a number of cases (from 0 up to 27.6%). Its origin remains unclear, but bone remodelling, impingement, head necrosis and osteolysis have been incriminated. The aims of this study were to assess these issues and describe their consequences in a prospective series with a minimum follow-up of five years.

Method: Fifty-seven HRs in 53 patients (30 men, 23 women, average age 49.2±8.4 years) were included prospectively with clinical (WOMAC, UCLA activity score) and radiological evaluation at one, two and five years. All patients received the Durom™ resurfacing system (Zimmer, Warsaw, IN, USA), with cementless acetabular cup and cemented femoral implant. All cases were undertaken via a posterior approach. Femoral and acetabular implant positioning was assessed. The neck-to-head prosthesis (N/H) ratio was calculated at the junction of the neck with the femoral component and at mid-distance between the neck junction and the inter-trochanteric line (N1/2/H) on anterior-posterior view. Ion concentrations (chromium, cobalt and titanium) were measured at 12 months. We considered p< 0.05 as the significance level.

Results: The N/H ratio decreased significantly at one, two and five years in comparison to the postoperative data (p< 0.01 for all parameters) and N1/2/H declined significantly only at one and two years (p=0.003 and p=0.03, respectively). There was no difference in the N/H ratio or N1/2/H between two and five years. We encountered no deleterious consequences of FNN on clinical outcome, and no significant relationship with cup positioning, gender, body mass index or level of activity. Femoral positioning in valgus was associated with a decrease in N1/2/H at one and two years (p=0.02), whereas the N/ H ratio tended to be lower when cobalt concentration was elevated (p=0.08). Significant FNN was observed in two cases at two years (−12.9% and – 11.1%) with a localized and progressive femoral anterior-superior notch absent on immediate postoperative X-rays. At five years, we noted three other cases with circumferential FNN, limited at the junction neck-cup area (average narrowing around – 20% between two and five years). One of these cases presented a femoral stem fracture. Osteonecrosis was confirmed during surgical revision.

Conclusion: In the current group, FNN was seen infrequently up to five years after surgery (9%). Mechanically-induced remodelling should be differentiated from overall FNN which may be due to femoral head necrosis. In this case, revision could be proposed before implant failure or femoral loosening. Impingement causes very early and localized FNN at the upper part of the neck; for these patients, simple observation should be the rule, all the more since they are usually pain-free and rarely disabled.


Richard W McCalden Robert B Bourne Kory D Charron Steven JM MacDonald Cecil H Rorabeck

Purpose: The Synergy femoral component was introduced in late 1996 as a second generation titanium proximally porous-coated tapered stem with dual offsets (standard & high) to help better restore femoral offset at THR. The purpose of this prospective study was to evaluate the long-term (minimum 10 year) clinical and radiographic results and survivorship of this second-generation femoral component at our institution.

Method: From December 1996 to December 1999, 256 cementless Synergy femoral components were inserted and followed prospectively in 254 patients requiring THR. 185 were standard offset stems(72.3%) while 71 stems (27.7%) were high offset. The average follow-up was 11.2 years (range 10.0 to 12.9 years). Average age at index THR was 58.9 years (range 19 to 86 years). Two hundred eight stems had standard porous coating while 48 had additional HA coating. Fifty-two cases were either lost to follow-up or had died prior to 10 years follow-up. Patients were followed prospectively using validated clinical outcome scores (WOMAC, SF-12, Harris Hip scores) and radiographs. Kaplan-Meier survival analysis was performed.

Results: All health-related outcomes were significantly improved from pre-operative with a mean Harris Hip score and WOMAC at last follow-up of 91.6 and 81.8, respectively. From the initial 256 femoral stems inserted, only 5 stems have been revised. Two stems have been revised for infection. To date, only one stem has been revised due to subsidence at nine months following surgery likely, as a result of a calcar fracture occurring at the index THR. Two stems were revised for peri-prosthetic fracture as a result of patient falls at six months and 9.8 years post-op. Radiographic review of remaining stems in-situ identified no cases of loosening with all stems showing evidence of osseous integration. The Kaplan-Meier survivorship analysis of the femoral component, with revision for aseptic loosening, was 99.2%±0.008 at five, 10 and 12 years.

Conclusion: The Synergy femoral component, a second generation titanium proximally porous-coated tapered stem design with dual offsets, has demonstrated excellent clinical & radiographic results and long-term survivorship (99% at 10 years) at our institution.


André Nzocou Jean-Michel Laffosse Alain Roy Martin Lavigne Pascal-André Vendittoli

Purpose: Massive cavitary and segmental bone defects of the medial wall in revision arthroplasty are usually managed with large auto and/or allograft in association with a cemented or a cementless cup. To obtain a satisfactory hip center reconstruction with such a procedure can be sometimes challenging and the complications rate can be high. One other option is the use of a cup with a medial expansion (“protrusio cup”) to treat the medial bone defect.

Method: We carried out a retrospective study including 21 consecutive acetabular revisions arthroplasties using a cementless Converge Protrusio™ cup (Zimmer, Warsaw, IN, USA). Clinical outcomes were assessed by Harris Hip Score (HHS), WOMAC index and SF-12. Hip centre was assessed on anteroposterior (AP) view and the reconstruction was considered as satisfying when its location was located from − 10 to + 10 mm proximally (y axis) and/or medially (x axis) in comparison with ideal theoretical hip center location. Cup migration and modification of abduction angle were considered as significant when there were respectively > 4mm and to > 4° in comparison with the immediate postoperative AP view.

Results: At the last follow up [radiological data: 71.6 months (24–128.3) and clinical data: 72.1 months (24–129.5)], two patients were died and there were no lost of follow up. The mean HHS was 79.4% (52–100), WOMAC 82% (46–100), SF-12 52 (23–71) and 44 (18–65). Bone defect were filled with cancellous bone chips allograft in 16 cases and bulk bone allograft was used in only two cases to manage a large segmental defect of the roof. Bone graft integration was completed in all cases. The mean abduction cup angle was 43.6° (32–60). A satisfying hip centre positioning was obtained in 19 cases on x axis and in 10 cases on y axis, in all the remaining cases, we noted an improved implant positioning. The complications were: recurrent dislocation in one case (successfully revised with a constrained liner), infection in two cases (1 treated conservatively and the other one revised in two times procedure) and Brooker’s type III and IV ectopic ossifications in three cases. A significant cup migration occurred in only one case at nine years but was not revised because of painless. No case required revision for aseptic loosening.

Conclusion: Protusio cups appear as a reliable procedure to manage bone loss in acetabular revision. The revision procedure is widely simplified by reducing the use of the massive allograft and by promoting a satisfying hip center reconstruction to allow an optimal biomechanical joint functioning. Moreover, the cementless fixation in contact with patient acetabular bone makes more easy bone integration.


Michael Gross David Amirault Michael J Dunbar

Purpose: To report a series of unexpected femoral neck failures in a series total hip replacement surgeries using a modular femoral component.

Method: A series of 443 hip replacement patients received modular necks as part of a non cemented hip replacement with ceramic articulations at the acetabulum and femoral head interface. The first implant of the device was on June 8, 2004 and the last on June 12, 2009. Ninety-one of those patients were enrolled in a RSA study of component stability within the proximal femur.

Results: The index fracture of a femoral neck occurred on March 8, 2009 when the patient (28 months post hip replacement) reported a fall. Subsequently five patients have had a fracture of the modular neck. There were five fractures within the RSA study group and one within the non study group (all occurred 17 months to 30 months post op). All fractures were long necks (10.5 mm). There was no difference in femoral component micromotion as measured with RSA between the fractured group and the unrevised group.

Conclusion: Initial non-destructive testing of one retrieval revealed fatigue failure of the femoral neck. An independent study of all relevant data was implemented which included destructive testing of the implants and clinical data with respect to patient activity. We report the outcome of all those investigations.


Christopher W Reilly Firoz Miyanji Kishore Mulpuri Davor Saravanja Peter O Newton

Purpose: Upper cervical spine stabilization in children can be challenging due to anatomic abnormalities such as incomplete posterior elements, vertebral artery variability and small patient size. Several techniques have been described for stabilization of the upper cervical spine, each with its own advantages and disadvantages. Since the introduction of the technique by Harms, many authors have shown C1 lateral mass screws to be safe and effective in the stabilization of the upper cervical spine in adults. No large series of paediatric C1 lateral mass screw fixation has been reported in the literature. The purpose of this study was to describe the indications, technique, and outcomes of C1 lateral mass screw fixation in a consecutive series of 11 paediatric patients.

Method: A database generated retrospective review of all patients who underwent C1 lateral mass screw fixation as part of an upper cervical spine stabilization construct was performed. In all patients the C2 dorsal root ganglion was sacrificed. Patient demographics and clinical outcomes were obtained through chart review. Radiographs immediately post-operatively, at six-weeks, three-months, and final follow-up were reviewed.

Results: Eleven consecutive paediatric patients underwent bilateral C1 lateral mass screw fixation for a variety of conditions including C1-C2 instability, deformity, congenital malformation, trauma, as well as revision surgery. The average age was 10 years (range 4 to 16 years) with a mean follow-up of 11 months (range 6 – 18 months). There were no iatrogenic vertebral artery, hypoglossal nerve or spinal cord injuries. All 11 patients had solid fusion clinically and radiographically, with no loss of fixation. The C2 dorsal root ganglion was sacrificed in all patients with resulting minor occipital parasthaesia that progressively diminished in severity.

Conclusion: This is the largest series of consecutive patients reported in the literature to date showing that the technique is safe and effective, with acceptable morbidity when applied to the paediatric population. We believe that C1 lateral mass screws offer significant advantages over traditional fixation techniques when the C1 vertebra is to be included in an upper cervical instrumented construct.


George H Thompson Amr Abdelgawad Douglas G Armstrong Connie Poe-Kochert Jochen P Son-Hing

Purpose: Posterior spinal fusion (PSF), with or without anterior spinal fusion (ASF), in conjunction with Luque rod instrumentation (LRI) and Galveston technique is a common procedure in neuromuscular spinal deformity. However, few studies have specifically studied the long-term results and complications of Galveston technique. The purpose of this study was to analyze the long-term results of Galveston technique in combination with PSF, with or without ASF, and LRI in the correction of neuromuscular spinal deformity. We were specifically interested in the stability of the distal foundation, lumbosacral fusion, correction of the associated pelvic obliquity, and complications.

Method: Analyzing our Pediatric Orthopaedic Spine Database between 1992–2006, we identified 107 consecutive patients with a neuromuscular spinal deformity who underwent a PSF, with or without ASF, and LRI including Galveston technique, who had a minimum of 2 years postoperative follow-up. There were 55 females and 52 males with a mean age at surgery of 13.5 ± 3.5 years. The mean follow-up was 7.8 ± 3.7 years. We analyzed the coronal and sagittal plane alignment and pelvic obliquity preoperatively, postoperatively, and at last follow-up. We recorded any complications directly related to the Galveston technique.

Results: The mean preoperative major curve was 76 ± 21 degrees. At last postoperative follow-up, this measured 33 ± 16 degrees. The mean preoperative pelvic obliquity was 17 ± 10 degrees and at last follow-up 7 ± 6 degrees. Seven patients (6.5%) had Galveston technique complications: three rod breakages, three implant distal migrations and one patient with both rod breakage and distal migration. These occurred late and only one patient required revision surgery.

Conclusion: The Galveston technique is an excellent procedure for lumbosacral stabilization in patients with neuromuscular spinal deformity. It provides a solid distal foundation for a lumbosacral fusion and for correction of spinal deformity and pelvic obliquity, with minimal complications.


Zachary Morison Gordon A Higgins Michael Olsen Peter M Lewis Emil H Schemitsch

Purpose: Surgeons performing hip resurfacing antevert and translate the femoral component anteriorly to maximize head/neck offset and reduce impingement. The anterior femoral neck is under tensile forces during gait similarly to the superior neck [6]. This study was designed to determine the risk of femoral neck fracture after anterior or posterior notching of the femoral neck.

Method: Forty seven fourth generation synthetic femora were implanted with Birmingham Hip Resurfacing prostheses (Smith & Nephew Inc. Memphis, USA). Implant preparation was performed using imageless computer navigation (VectorVision SR 1.0, BrainLAB, Germany). The prosthesis was initially planned for neutral version and translated anterior, or posterior, to create a femoral neck notch. The femora were fixed in a single-leg stance and tested with axial compression using a mechanical testing machine. This method enabled comparison with previously published data. The synthetic femora were prepared in eight experimental groups:two mm and five mm anterior notches, two mm and five mm posterior notches, neutral alignment with no notching (control), five mm superior notch, five mm anterior notch tested with the femur in 25° flexion and five mm posterior notch tested with the femur in 25° extension We tested the femora flexed at 25° flexion to simulate loading as seen during stair ascent. [3] The posterior five mm notched femoral necks were tested in extension to simulate sporting activities like running. The results were compared to the control group in neutral alignment using a one – way ANOVA:

Results: Testing Group Mean load to failure Significance (p-value) Anterior 2mm 3926.61 ± 894.17 .843 Anterior 5mm 3374.64 ± 345.65 .155 Neutral (Control) 4539.44 ± 786.44 – Posterior 2mm 4208.09 ± 1079.81 .994 Posterior 5mm 3988.06 ± 728.59 .902 Superior 5mm 2423.07 ± 424.17 .001 Anterior 5mm in 25° flexion 3048.11 ± 509.24 .027 Posterior 5mm in 25° extension 3104.62 ± 592.67 .038 Our data suggests that anterior and posterior two mm or five mm notches are not significantly weaker in axial compression. Anterior and posterior 5mm notches are significantly weaker in flexion/extension (p=0.027/ p=0.038). The five mm superior notch group was significantly weaker with axial compression supporting previous published data (p=0.001).

Conclusion: We conclude that anterior or posterior two mm notching of the femoral neck has no clinical implications, however five mm anterior or posterior femoral neck notching significantly weakens the femoral neck. Fracture is more likely to occur with stair ascent or activities involving weight bearing in extension. Hip resurfacing is commonly performed on active patients and five mm neck notching has clinically important implications.


Tristan Camus Ronald El-Hawary Brent MacLellan P. Christopher Cook J. Lorne Leahey John C Hyndman

Purpose: The treatment of extension type II pediatric supracondylar humerus fractures remains controversial. Some argue that closed reduction and cast immobilization is sufficient to treat these fractures, while others advocate closed reduction and pinning. The purpose of this radiographic outcomes study was to determine whether closed reduction and cast immobilization could successfully obtain and maintain appropriate position of extension type II supracondylar humerus fractures.

Method: The radiographs of 1017 pediatric patients treated for supracondylar fractures between 1987 and 2007 were retrospectively reviewed. Pre-reduction, immediate post-reduction, and final radiographs of 155 extension type II fractures were measured in order to assess the position and alignment of the fracture fragments. Measurements included the anterior humeral line, humeral-capitellar angle, Baumann’s angle, the Gordon index, and the Griffet index. The latter two indices calculate the rotational instability of the fracture, which can be predictive of reduction loss. Patients were excluded if insufficient radiographs failed to allow complete assessment of the measurement parameters, or if open reduction was required.

Results: The average age of the subjects was 5.3 years (range 1–13 years) and had a mean follow-up of 5.3 months. Analysis of the final radiographs demonstrated that in 80% of subjects, the anterior humeral line remained anterior to the mid third segment of the capitellum (radiographic extension deformity), the mean humeral-capitellar angle was 23.8° (range – 11°–50°), the mean Baumann’s angle was 79.4° (range 62°–97°), the mean Gordon index was 4.59%, and 44% of subjects had a Griffet index between 1–3 (potentially indicative of unstable reduction due to malrotation of the fragments, which can allow the development of a cubitus varus deformity).

Conclusion: From this radiographic review, a significant proportion of fractures treated with closed reduction and cast immobilization failed to achieve anatomic position and alignment on final x-rays. However, the clinical significance of these results and the potential for long-term re-modeling of these fractures remains unknown.


Stephen Yang Reggie Hamdy Noemi Dahan-Oliel

Purpose: Arthrogryposis Multiplex Congenita is a rare congenital disorder associated with multiple musculo-skeletal contractures which causes substantial morbidity. Knee involvement is commonly seen among children with arthrogryposis, with flexion contracture of the knee being the most frequent knee deformity. Knee flexion contractures in the paediatric population are particularly debilitating as they affect ambulation. Treatment for knee flexion contractures requires numerous orthopaedic procedures and an extensive follow-up period. The purpose of this study was to assess the effectiveness of orthopaedic procedures, namely distal femoral extension osteotomy and/or Ilizarov external fixator, on the ambulation status of children with knee flexion contracture.

Method: The medical records and radiological images of 16 paediatric patients with arthrogryposis and knee flexion contractures were reviewed. The etiology of all of them was amyoplasia except for one case of popliteal pterygium. The mean age of first surgery was 6.2 years (age range: 1–15 years). The mean length of follow-up was 83.9 months. All patients’ knee flexion contractures were treated with femoral extension osteotomy, Ilizarov external fixator, or both. Two patients previously had posterior soft tissue releases, including hamstrings lengthenings, proximal gastrocnemius release, and release of posterior capsule.

Results: Prior to the initial surgery for knee flexion contracture, 13 patients were non-ambulatory. One patient was a household ambulator with flexed knees. Two patients walked with orthoses. There was an average of 1.8 surgeries done per patient, namely distal femoral extension osteotomy and/or Ilizarov external fixator. At the latest follow-up, 12 patients were ambulatory, including 11 children ambulating with technical aids (orthosis, walker, braces, or rollator walker) and one child ambulating without any technical aid. Four patients remained non-ambulatory. The mean total arc of motion was 64.8 degrees preoperatively, 63.1 degrees postoperatively, and 52.8 degrees at the latest follow-up. A mean loss of 6.8 degrees per year in total arc of motion occurred. There were complications in four patients which consist of infected hardware, transient neurological compromise, cast change, and pressure sore.

Conclusion: Surgical correction of knee flexion deformities by distal femoral extension osteotomy and/or Ilizarov external fixator was effective in improving the ambulation status of children with arthrogryposis. At latest follow-up, the gradual loss of total arc of motion did not impact the ambulatory gains made by these procedures.


Joshua AM MacNeil Ronald El-Hawary Antony Francis

Purpose: Fractures of the femoral diaphysis are common injuries in the paediatric population. Rigid, locked, intramedullary nailing allows for early mobilization, but is usually reserved for older children and adolescents. Avascular necrosis (AVN) of the femoral head is a rare but serious complication of this technique. The entry site of the nail has been speculated to have an effect on this risk. Different nail entry sites have been used and include the piraformis fossa, tip of the greater trochanter, and the lateral greater trochanter. The purpose of this study is to complete a review of the literature to determine the effects of nail entry site on the risk of proximal femoral AVN.

Method: The English medical literature (Pubmed, Embase, Cochrane database, and relevant articles from the bibliographies) was searched and 1277 articles were identified. Articles were excluded if they were case reports, if they did not examine long term complications, or if the insertion location could not be determined. Patients treated using each insertion site were combined together for analysis to determine the overall AVN and complication rate for each site.

Results: From the 1277 articles identified, 19 articles met the inclusion criteria. The piraformis fossa treatment group included 239 patients and had an AVN rate of 2%. The tip of the greater trochanter treatment group included 139 patients and had an AVN rate of 1.4%. The lateral greater trochanter treatment group included 80 patients and had no reported cases of AVN. Other complications included length discrepancy, heterotrophic ossification, and changes in proximal femoral morphology (articular trochanteric distance, neck shaft angle, trochanter to trochanter distance, and femoral neck diameter).

Conclusion: Based on the current literature, the lateral greater trochanteric entry site for rigid, locked intra-medullary nailing has a lower risk of AVN as compared to the piraformis fossa and the tip of the greater trochanter entry sites.


Sulamain Almousa Paul E Beaulé

Purpose: Iatrogenic acetabular retroversion is a known complication after pelvic osteotomy leading to persistent hip pain and increasing risk of subsequent osteoarthritis. The purpose of this study is to document the incidence of acetabular retroversion and signs of impingement in patients who have had a Salter pelvic osteotomy in childhood.

Method: Twenty eight patients (32 hips) had a Salter Osteotomy between 1980 and 1999, 16 were lost to follow-up. Of the 12 studied, eight had a diagnosis of DDH and four had Legg Calve Perthes. Clinical assessment for the presence of the impingement sign, range of motion and leg length discrepancy was done as well as functional scores. AP pelvic radiographs were taken to assess acetabular retroversion (cross-over or ischial sign), osteoarthritis using the Tonnis grade, center-edge and Tonnis angles.

Results: The mean age of the sample was 17.25 years (SD=7.27) with a mean follow-up of 10.56 years (SD=6.27). Impingement sign was positive in seven patients (58.3%). Nine out of the 12 had acetabular retroversion. Nine had Tonnis grade 1, two Tonnis grade 2, and one had a Tonnis grade 3. Mean center edge and Tonnis angles were 26° (SD=16.43) and 9.09° (SD=6.49), respectively. There was no correlation between presence of acetabular retroversion with Tonnis grade (p=.700), hip pain (p=.317) or impingement sign (p=.621).

Conclusion: Retroversion is highly prevalent (69.2%) in patients who underwent a Salter pelvic osteotomy for a childhood hip disease. Although acetabular retroversion is a known cause of impingement in adulthood, our patient cohort was too small to detect a significant impact on the functional scores.


Renjit Varghese Firoz Miyanji Christopher W Reilly Suken Shah Amer F Samdani Peter O Newton Kishore Mulpuri

Purpose: The wait for surgical treatment of scoliosis is long in some countries, especially in those with publicly funded health care systems. Long wait times may have serious consequences if the deformity increases during the wait period. This study was undertaken to determine the surgeon’s perspective of the type and magnitude of surgery required with specific emphasis on peri – and post-operative measures, for patients with scoliosis on prolonged waitlist times (> 6 months) for surgery.

Method: Radiographs from 11 patients who had a Cobb angle of at least 50 degrees and had waited 6 or more months for scoliosis surgery selected from the scoliosis database. All patients had antero-posterior (AP), AP bending, and lateral radiographs taken when the primary curve magnitude was 50 degrees and at the time of pre-operative planning. 22 radiographic sets and a questionnaire were sent to three different surgeons. The surgeons were blinded to the fact that these sets contained films of the same patients at two different time points. The questionnaire requested information with regard to the type of surgery and instrumentation they would use, other peri-operative measures, and time taken to return to normal activities.

Results: The mean curve progression in the 11 patients was 25 degrees over the time on the waitlist, from an average of 50 degrees to 75 degrees. The type of surgery the surgeon would likely perform changed from posterior instrumentation and fusion with a screw construct in all patients to anterior release and posterior instrumentation and fusion with a screw construct in 8 of the 11 patients, in at least one surgeon’s opinion. The mean estimated operative time increased by 2 hours. The mean estimated length of stay at the hospital increased by 1 day, and the estimated level of difficulty of surgery increased from 3/10 to 5/10.

Conclusion: From a surgeon’s perspective, waits of 6 months or more for scoliosis surgery are unacceptable as they lead to the need for a second anterior procedure that probably would have not been necessary had the operation occurred earlier. It also leads to increased operative time, blood loss, length of stay, and difficulty of surgery. This, in turn, increases unwarranted risks and costs.


Andrew W Howard Andrew Willan Kathy Boutis

Purpose: In skeletally immature children with acceptably angulated (< = 15 degrees angular deformity at presentation) distal radius and/or ulnar fractures, to determine if a pre-fabricated wrist splint is at least as effective as a cast. The primary outcome was recovery of physical function six weeks after the injury as measured by the validated Activities Scale for Kids. Secondary objectives included determining differences in angulation of fracture, wrist range of motion, wrist strength, pain with movement, return to baseline activities, and patient preferences at six weeks.

Method: A randomized controlled, non-inferiority, single (evaluator) blinded, single-centre trial in a tertiary care pediatric emergency department. Minimal required sample size of 76 patients with was based on testing the null hypothesis (H0) that the brace is 7% less effective at the 2.5% level. Physical function was tested by a t-test for a non-zero difference. For the other outcomes, proportions and means were compared with the Fisher Exact and Student s t-test, respectively.

Results: Of the 100 randomized patients, 3 were excluded due to non-eligibility on radiographic review. 93 of the 97 completed full clinical, radiographic, and patient determined followup. ASK scores at six weeks were 92.8 in the splint group and 91.4 in the cast group, neither clinically nor statistically significantly different. Among patients treated in a cast, the average angular deformity at followup was 11.0 degrees and compared with an average of 6.6 degrees angulation among patients treated in a splint (p=.02, t-test). These groups were equal at baseline, with an average of 7.5 degrees of angulation in the cast group and 6.7 degrees in the splint group. Complications did not differ between groups, nor did range of motion with the exception that pronation was slightly better (84 versus 74 degrees) in the splint group at the end of treatment. No patient required any operative procedure. Parents preferred splinting over casting (p< 0.001) and children preferred splinting over casting (p=0.028).

Conclusion: Splinting was non-inferior to casting, and in fact may be superior to casting, for maintaining the position of a minimally displaced distal radial metaphyseal fracture. Significance: The benefits of splinting over casting have been previously established for undisplaced distal radius and ulnar fractures (Plint), this is the first study which extends these benefits to the large group of children with minimally displaced distal radius fractures. Splint treatment simplifies care for children, reduces cost, and improves short term outcomes.


Jason J Howard Catherine Hui Alberto Nettel-Aguirre Elaine Joughin Simon Goldstein James Harder Gerhard Kiefer David Parsons

Purpose: Congenital idiopathic clubfoot is the most common congenital deformity in children and can be a major cause of disability for the child as well as an emotional stress for the parents. The Ponseti method of club-foot correction, consisting of serial manipulations and casting, is now the gold standard of treatment. It has traditionally been described using plaster of Paris (POP) above-knee casts, which are affordable, stiff, and easily moldable. Recently, semi-rigid fiberglass softcast (FSC, 3M Scotchcast) has grown in popularity due to ease of removal, durability, lighter weight, better appearance, ease of cleaning, and water resistance. There are currently no randomized controlled trials to prove its efficacy with respect to POP. The purpose of this study was to determine the influence of choice of cast material on the correction of congenital idiopathic clubfeet using the Ponseti method.

Method: A prospective, randomized controlled trial. Based on the results of a pilot study performed at our centre, a sample size of 30 patients was determined to be appropriate. Thirty consecutive patients presenting with congenital idiopathic clubfoot were randomized into POP and FSC groups prior to commencement of treatment with the Ponseti Method. Clubfeet secondary to non-idiopathic diagnoses were excluded. The Pirani classification was used to determine clubfoot severity (less severe, < =4; severe > 4), and for surveillance during casting. The primary outcome measure was the number of casts required to correct the clubfoot deformities to the point where the foot was ready for a percutaneous tendo-achilles tenotomy (TAL) or when the foot was completely corrected (Pirani=0). Secondary outcome measures include: number of casts by clubfoot severity, ease of cast removal, number of methods needed to remove casts, need for percutaneous tendo-achilles tenotomy.

Results: Of the 30 patients enrolled, 13 (40%) were randomized to POP and 18 (60%) to FSC. No patients were lost to follow-up. In the POP and FSC groups, eight (67%) and 11 patients (61%) underwent a TAL, respectively. In general, there were no differences in the mean number of casts required for clubfoot correction between the two groups (p=0.13). When analyzed by clubfoot severity, the mean number of casts for each material in the less severe group was equal (3 casts). In the severe group, the mean number of casts in the FSC group (6.4 casts) was considerably higher than for the POP group (4.7 casts) but our study was underpowered to verify this result. According to parents, POP was harder to remove than FSC (p< 0.001).

Conclusion: In general, FSC was found to be as efficacious as POP in the correction of idiopathic clubfeet by the Ponseti Method and was the preferred cast material by parents. For stiffer, more severe feet, POP seemed to show a faster correction time than FSC.


Randy Mascarenhas Eden Raleigh Sheila McRae Jeffrey Leiter Peter B MacDonald

Purpose: Performing a labral repair alone in patients with recurrent anterior instability and a large glenoid defect has led to poor outcomes. We present a technique involving the use of iliac crest allograft inserted into the glenoid defect in athletes with recurrent anterior shoulder instability and large bony defects of the glenoid (> 25% of glenoid diameter) We hypothesized that restoring a near-normal glenoid structure would prevent further dislocations and that osseous union would be achieved

Method: All athletes with recurrent anterior shoulder instability and a large glenoid defect who underwent open anterior shoulder stabilization and glenoid reconstruction with iliac crest allograft were prospectively followed over a three year period. Pre-operatively, a detailed history and physical exam was obtained along with radiographs, a CT scan, and magnetic resonance imaging of the affected shoulder. All patients also complete the Simple Shoulder Test (SST) and American Shoulder and Elbow Surgeons (ASES) evaluation forms pre – and post-operatively. A CT scan was again obtained 6 months post-operatively to assess osseous union of the graft, and the patient again when through a physical exam in addition to completing the SST, ASES, and Western Ontario Shoulder Instability Index (WOSI) forms.

Results: Nine patients (all male) were followed for an average of 16 months (4 – 36 months) and had a mean age of 24.4 years. All patients exhibited a negative apprehension/ relocation test and full shoulder strength at final follow-up. Eight of nine patients had achieved osseous union at six months (88.9%). ASES scores improved from 64.3 to 96.7, and SST scores improved from 66.7 to 100. Average post-operative WOSI scores were 94%.

Conclusion: The use of iliac crest allograft provides a safe and clinically useful alternative compared to previously described procedures for recurrent shoulder instability in the face of glenoid deficiency


Jason Peeler Jeffrey Leiter Peter B MacDonald

Purpose: This research project compared the accuracy of 3 methods of meniscal injury diagnosis that are commonly employed in a clinical orthopaedics: Clinical examination, MRI and Arthroscopic surgery.

Method: A retrospective review of charting was used to collect meniscal injury assessment data for 116 patients that had sustained an acute anterior cruciate ligament injury to one knee. Sixty-eight of the 116 patients had the presence of a meniscal lesion confirmed via surgery. Sensitivity and specificity of “hands on” clinical examination and MRI interpretation were determined using the results of arthroscopic surgery as the gold standard. Sensitivity and specificity of “hands on” clinical examination relative to MRI interpretation was also calculated. Finally, the findings of all three methods of meniscal evaluation were compared.

Results: Accuracy testing demonstrated that the sensitivity and specificity of clinical examinations (0.54 / 0.81) was comparable to levels observed for MRI (0.69 / 0.70), and when directly comparing the findings of clinical examination against MRI, that there was a high level of agreement when a meniscal lesion was not present (specificity: 0.91), but a much lower level of agreement when a meniscal lesion was suspected (sensitivity: 0.54). In general, when comparing the findings from clinical examination, MRI, and arthroscopic surgery, complete agreement among all 3 methods of evaluation occurred in only 51% of the patients.

Conclusion: Our results serve to highlight the inaccuracies associated with meniscal injury assessment when evaluating an acutely traumatized knee joint, and suggest that the incidence of secondary joint trauma following ligament injury may be under predicted.


Sultan Al-Dosari Sukhdeep K Dulai Edmond Lou John Andersen Joe Watt Kyle A Kemp

Purpose: Clinical gait analysis is considered the “gold standard” for evaluating individual walking patterns. However, in conditions where an individual may exhibit transient voluntary control of gait (such as idiopathic toe walking), their walking pattern in a gait lab may not accurately reflect their gait during daily activities. An accurate assessment of such patients’ functional gait is essential in determining appropriate management options and response to treatment. Therefore, a battery-powered, wireless data acquisition system (WDAS) was developed to record daily functional walking patterns. The goal of the present study was to compare the tilt angle and load data obtained from the WDAS with those measured by gait lab equipment in a sample of healthy adult volunteers.

Method: Seven members of the research team participated in our validation study. Following informed consent, the WDAS was attached to the dorsum (laces) of each subject’s right shoe. Two thin film load sensors were wired to the device and placed under the sole of the foot, inside the shoe. Three spherical markers were placed on the same foot (head of first metatarsal, head of fifth metatarsal, calcaneous). Data were simultaneously recorded by the WDAS (30 Hz) and gait lab (60 Hz). To calibrate the device, each subject performed three static standing tasks (normal standing, weight bearing on toes, weight bearing on heels). Each subject then performed five normal walking trials and five toe-walking trials over a ten-metre, level course.

Results: From the WDAS and gait lab, the average percentage of time spent on the toes (load values under first toe greater than zero) during the stance phase of normal gait was 50.2% and 67.4%, respectively. During toe walking, this increased to 98.9% and 99.8%, respectively. This indicates that the WDAS and gait lab are similar in their ability to discern between normal and toe-walking gait. For the inclination angle, within-subject correlation values of r = 0.76 and r = 0.92 were observed during normal walking and toe walking, respectively. This indicates acceptable levels of agreement between the inclination measures of the WDAS and gait lab.

Conclusion: The validity of angle data from the WDAS was confirmed, when compared to data retrieved from a formal, gait analysis lab. Furthermore, the WDAS was able to clearly differentiate between a normal and a toe walking pattern. The WDAS may assist clinicians in the diagnosis and treatment of gait abnormalities, based on information retrieved during daily activities.


Peter B MacDonald Robert McCormack Sheila McRae Jeffrey Leiter Mauri Zomar Jason Old Scott Wiens

Purpose: The hypothesis of this randomized controlled trial is patients undergoing ACL reconstruction using contralateral hamstring harvest will have better quality of life and strength than using ipsilateral graft.

Method: One hundred participants were assigned to the ipsilateral (IG) or contralateral (CG) group. Primary and secondary outcomes were ACL Quality of Life (ACL-QOL) and concentric isovelocity knee flexion/extension strength measured on a dynamometer at five speeds. Data was gathered pre-surgery, and at 3, 6, 12, and 24 months post-surgery. Findings to 12 months are presented.

Results: ACL-QOL scores and knee flexion/extension strength were not significantly different between groups across time. Comparing side-to-side strength within each group, knee extension strength was consistently higher on the non-reconstructed side. In the IG, there were no side-to-side differences in knee flexion strength. In the CG, flexion on the reconstructed side was stronger than the grafted side early post surgery (3, 6 months) at 60 degrees/s, but this pattern was reversed at 90, 150, and 210 degrees/s. Post-hoc comparisons revealed hamstring/ quadriceps (H/Q) ratios were not different between limbs in the CG or for the uninvolved limb for the IG. However, at most time points and speeds, the H/Q ratio for the involved limb in the IG was higher than the uninvolved limb in the IG and either limb in the CG.

Conclusion: This study reveals that ipsilateral graft harvest may alter the H/Q ratio. It was also demonstrated that contralateral graft harvest may normalize this effect. This may have some bearing on function and re-injury risk that should be further investigated.


Catherine Hui Lucy Salmon Alison Kok Shinichi Maeno Leo Pinczewski

Purpose: The management of degenerative arthritis of the knee in the younger, active patient often presents a challenge to the orthopaedic surgeon. Surgical treatment options include: high tibial osteotomy (HTO), uni-compartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA). The purpose of this study was to examine the long-term survival of closing wedge HTO in a large series of patients 8–19 years after surgery.

Method: The results of 458 consecutive patients undergoing lateral closing wedge HTO for medial compartment osteoarthritis (MCOA) between 1990 and 2001 were reviewed. Between 2008–2009, patients were contacted via telephone and assessment included: incidence of further surgery, Oxford Knee Score, and British Orthopaedic Association (BOA) Patient Satisfaction Scale. Failure was defined as the need for revision HTO or conversion to UKA or TKA. Survival analysis was completed using the Kaplan-Meier method.

Results: We were able to contact 400/458 (87%) patients for follow-up via telephone interview. Five patients (1%) who declined participation were excluded. Fifty-eight patients (13%) were lost to follow-up. Of the 395 patients, 12 (3%) had died of unrelated causes and 124 (31%) required further knee surgery. The remaining 259 (66%) completed the BOA patient satisfaction score and Oxford Knee Score. The probability of survival for HTO at 5, 10 and 15 years was 95%, 79% and 55% respectively. Multivariate regression analysis showed that only age < 50 years (p< 0.001) was associated with significantly longer survival. Mean Oxford Knee Score was 40/48 (range 17–60). Ninety-two percent (239/259 patients) were enthusiastic or satisfied and 90% (234/259 patients) would undergo HTO again at mean 11 years follow-up. Complications included: 5 pulmonary embolisms, 8 deep vein thromboses, 1 non-union, 1 post-operative subarachnoid hemorrhage and 1 transient peroneal nerve palsy.

Conclusion: To our knowledge, we have reported the long-term follow-up of lateral closing wedge HTO in the largest group of patients in the literature. We found that the results of HTO do deteriorate over time but that HTO can be effective for as long as 19 years. In appropriately selected patients and circumstances, HTO gives high patient satisfaction and affords patients unrestricted activity for many years.


Anthony Marchie Ian Panuncialman Joseph C McCarthy

Purpose: Synovial chondromatosis is a cartilaginous metaplasia that can result in multiple intracapsular and extracapsular loose bodies. Open arthrotomy has been the conventional treatment for this condition in the hip, but is associated with neurovascular embarrassment and femoral head osteonecrosis. Hip arthroscopy avoids these problems, and is a minimally invasive approach to diagnosis and treatment. Our aim was to evaluate the role of arthroscopy in the management of synovial chondromatosis of the hip at the early-to-intermediate stages of disease.

Method: Twenty-nine patients had arthroscopic treatment for synovial chondromatosis of the hip. All lesions were intracapsular and smaller than 10mm. Radiographs of the painful hip, computed tomography, and gadolinium-enhanced magnetic resonance imaging were obtained pre-operatively. During arthroscopy, loose bodies were removed via a cannula, and partial synovectomy, partial labrectomy, chondroplasty, and microfracture were done as needed.

Results: Fourteen patients were women and 15 were men; mean age was 41 years old; mean duration of symptoms was 52 months. All patients had hip pain. Mechanical hip symptoms were reported by 63% of patients. Twenty-three patients had a follow-up of at least 12 months (12 to 184 months of follow-up). Loose bodies could be seen in the imaging studies of 58% (15 of 29) of patients: 8 on radiographs and 7 with computed tomography or gadolinium-enhanced magnetic resonance imaging. At surgery, 23 of the 29 patients had torn or frayed labra. There was an average of 35 loose bodies per patient. Twenty-three of the 29 patients had femoral head changes, four of which had Grade III or IV lesions. Twenty-five of the 29 had acetabular chondral findings, ten of which had Grade III or IV lesions. Five of the 29 patients eventually underwent total hip reconstruction surgery at an average of 52 months follow-up; four of these 5 patients had at least a Grade III lesion at the time of arthroscopy. Eleven of the 23 patients who had a minimum of 12 months follow-up (12 to 184 months) had good to excellent outcomes at an average of 60 months follow-up. Complications included a case of perineal numbness and another with tingling of the foot.

Conclusion: Our patients with synovial chondromatosis of the hip benefited from hip arthroscopy. Imaging studies alone, including gadolinium-enhanced MRI, failed to establish the diagnosis in half of the patients. Diagnosis was eventually made by direct visualization of the loose bodies via arthroscopy. None of our patients had subsequent femoral head osteonecrosis or infection. For patients who had Grade I or II cartilage lesions, early diagnosis and treatment via arthroscopy helped prevent or delay the onset of secondary osteoarthritis. Arthros-copy also avoided an open surgical exposure with its associated prolonged rehabilitation. It is a valid and effective treatment for early-to-intermediate stages of synovial chondromatosis.


Mark Hurtig Mark Lowerison Paul Marks

Purpose:

To develop a method for depth-wise analysis of subchondral bone that considers the gradient of bone volume, density and organization between the articular surface and the marrow cavity.

To understand the interplay between subchondral bone changes and extrinsic cartilage repair after microfracture.

Method: Since 30% of patients fail microfracture for contained chondral lesions, our hypothesis was that early subchondral sclerosis increases compaction of bone around microfracture holes, leading to failed cartilage repair. Human osteochondral segments from the knee joint were characterized macroscopically using the Outerbridge score, then imaged at 45 micron resolution using microCT. Regions of interest (ROI) were chosen under normal cartilage and abnormal cartilage (Outerbridge Score=1). Routine Bone mineral density (BMD) analysis was performed on each ROI using GE MicroView™ analysis software. Additional depth-wise analysis of BMD was done by exporting each ROI was a density map, and calculating the mean, standard deviation and rate of change of BMD by slice in the vertical (coronal) plane. Plots of normal and early OA data by depth were compared. Microfracture holes were made in normal and sclerotic subchondral bone, and depth-wise measurements of subchondral compaction around the holes were made were made.

Results: Bone under normal versus OA cartilage was very subtly different in microCT images, but ROI microCT analysis showed that the OA samples were more mineralized and contained more bone. Using the depth-wise analysis algorithm, automated detection and measurement of the subchondral bone plate and other discrete structures was possible. The depth-wise analysis confirmed that the osteoarthritic subchondral bone plate had a higher BMD and bone volume fraction, but also showed that the rate of change (gradient) in BMD was greater. Horizontally orientated trabeculae and other anomalies were found in OA bone that contributed a more variable BMD in trabecular bone at up to 5 mm from the articular surface. Bone with early sclerotic changes had significantly (p< .01) more bone volume fraction and BMD (p< .05) around microfracture holes in this ex vivo experiment.

Conclusion: An enhanced picture of subchondral bone plate and trabecular bone anomalies can be appreciated using a depth-wise approach to image analysis. Both sclerosis and osteopenia have been reported in OA and models of OA, but this analysis shows that variability and gradient of BMD change adjacent to the articular cartilage is a significant feature of OA. This is consistent with some theories of OA progression that implicate stress concentration between the cartilage and subchondral bone plate leading to cartilage degeneration. More importantly, bone sclerosis has a direct effect on the amount of compaction around microfracture holes, so improvements in microfracture technique are needed to avoid this.


Shalinder S Arneja Morgan Jones Anthony Miniaci

Purpose: Historically, there have been few surgical options for patients with focal full-thickness cartilage lesions in the knee who have failed or are too advanced in age for biologic resurfacing treatments, yet are also relatively too young or unwilling to undergo conventional total or unicompartmental knee arthroplasty. The UniCAp knee resurfacing arthroplasty provides an option for these patients that is minimally invasive, preserves the menisci and cruciate ligaments, and retains the bony architecture of the knee joint, thereby providing the potential for a rapid recovery to more vigorous activities than might be permitted after conventional knee arthroplasty, while preserving range of motion. The objective of this study was to examine the clinical results of a patient cohort undergoing the UniCAP knee resurfacing in the medial compartment of the knee.

Method: Prospective patients were screened with history and clinical examination, weight-bearing radiographs, and MRI. Patients were offered UniCap knee resurfacing arthroplasty if they had symptomatic full-thickness cartilage lesions in the medial and/or patellofemoral compartments. The cohort included 38 cases in 35 patients who underwent the UniCAP knee resurfacing procedure in the knee with focal medial compartment (with or without patellofemoral) osteoarthritis in the knee joint. In addition, patients were assessed with validated and established outcome scales including the International Knee Documentation Committee Subjective Form, the Knee Injury and Osteoarthritis Outcome Scale, which includes the WOMAC Osteoarthritis Index.

Results: The average age of patients undergoing knee resurfacing was 48.25 years (Range: 23 to 80). There were 24 males and 12 females. Thirty-one patients underwent isolated medial compartment resurfacing and 7 patients received both a medial compartment resurfacing and trochlear resurfacing. Three patients underwent a concomitant ACL reconstruction and 1 patient underwent a concomitant high tibial osteotomy. The mean duration of follow up was 18 months (Range: 12 to 26 months). There was an overall mean improvement from the pre-operative to post-operative scores in the IKDS-SF (P < 0.01), KOOS (all domains, P < 0.01) and WOMAC Index (P < 0.01). There were no major complications such as deep infection, DVT, or implant failure. In addition, there was no evidence of mechanical symptoms/signs or radiographic evidence of loosening at any time point post-operatively.

Conclusion: The short-term results demonstrate that the UniCAP resurfacing arthroplasty in the knee is a viable treatment option for focal full thickness cartilage lesions in the medial compartment of the knee in patients who are no longer candidates for biologic resurfacing procedures and who are also relatively too young or unwilling to undergo conventional total or unicompartmental knee arthroplasty.


Bashar Alolabi Bryant Dianne Peter J Fowler Kevin Willits J Robert Giffin

Purpose: Medial opening wedge high tibial osteotomy (MOW-HTO) is a well-described operative method for the treatment of medial gonarthrosis in selected patients. One of the concerns with MOW-HTO is the potential delayed or nonunion across the medial gap. Traditionally, this gap was filled with autograft to facilitate union. Although alternative graft options, such as allograft, are available and have theoretical advantages over autograft, little is known about their efficacy relative to autograft in MOW-HTO. The purpose of our study was to perform a retrospective matched cohort study comparing union, re-operation and complication rates between autograft and morselized allograft as filler for the medial gap created in MOW-HTO.

Method: Forty patients who underwent MOW-HTO for sympathetic varus deformity with the use of autograft bone were matched for age, sex, body mass index, deformity and deformity correction with 40 patients who underwent the same procedure with the use of morselized bone allograft. The operative technique utilized, type of hardware fixation and rehabilitation program were similar for both groups. The primary outcome assessed was union rate as evaluated on radiographs by two independent blinded examiners. Re-operation and complication rates were assessed as secondary outcomes.

Results: A total of 73/80 patients in the study (91%) developed union, 4/80 (5%) developed nonunion, and 3/80 (4%) required early revision. The union rate was 95% and 88% in the autograft and allograft groups respectively. Three percent in the autograft and 8% in the allograft groups developed nonunion (p=0.64). Thirteen percent of the autograft patients required re-operation compared to 18% from the allograft patients (p=0.53). Complications were encountered in 28% of the autograft group and in 23% of the allograft group (p > 0.05). There was a 10% incidence of harvest site complications in the autograft group. The average operative time was 21 minutes shorter using allograft compared with using autograft (p< 0.01).

Conclusion: No statistical significant difference was demonstrated between the groups for union, re-operation rates and overall complication rates. However, the autograft group had a significant 10% incidence of harvest site complications and a statistically significant increased operative time. We conlcude that allograft is safe and efficacious to use in valgus producing MOW-HTO. Allograft avoids harvest site complications and is associated with decreased operative time when compared to autograft.


Nicole Simunovic Sheila Sprague Gordon H Guyatt PJ Devereaux Stephen D Walter Emil H Schemitsch Mohit Bhandari

Purpose: Unbiased outcome assessment in orthopedic clinical trials has the potential to improve trial validity. The approaches used to limit bias in outcome assessment in orthopaedic trials remain unclear. The objective of this systematic review was to assess the reporting and process of outcomes assessment practices in the current orthopaedic trauma literature.

Method: We searched eight high-impact-factor medical and orthopaedic journals manually and using the MED-LINE electronic database for reports of randomized controlled trials published from 2005 to 2008 pertaining to the surgical treatment of trauma-related injuries. Two reviewers independently determined study eligibility and extracted relevant data from included trials.

Results: Of the 7910 citations identified during our search, 47 randomized controlled trials, which included a total of 4706 patients, met our inclusion criteria. Of 47 studies, 39 (83%) provided a statement to describe some process of outcome assessment and 29 (74%) reported using an unblinded individual as the outcome adjudicator. Four studies (10%) reported using a second assessor to verify outcome measurements, and three studies (8%) reported the use of an adjudication committee to reach endpoint decisions via consensus. No included study provided a rationale for the use of their chosen approach to adjudication. The most commonly adjudicated outcomes included fracture healing (15 studies), reoperation rate (6 studies), and general clinical assessment of post-operative complications and limb function (30 studies), mainly by orthopaedic surgeons. Blinding of outcome assessors was not performed or unclear in 38 studies (81%).

Conclusion: Despite the importance of the outcome assessment process in orthopedic trauma trials, key aspects of outcome assessment are insufficiently reported. This limits the ability of readers to assess the validity of published trials.


Peter B MacDonald Jeffrey Leiter Sheila McRae Alan Hammond

Purpose: Damage to the infrapatellar branch of the saphenous nerve and subsequent loss of sensation following graft harvest in ACL reconstruction is common. An oblique incision, rather than a vertical incision, has been shown to reduce the incidence and area of sensory loss following graft harvest [1] although the results are not universal. The purpose of this study was to determine if there was a difference in the area of infrapatellar neuritis (IFPN) and quality of life (QOL) between ACL patients that received a vertical – (VI) versus oblique-incision (OI) for hamstring tendon harvest.

Method: An interim analysis of a single-blinded randomized controlled trial (N=100) was conducted. Patients with clinical – and/or MRI-evidence of an ACL tear and no previous injury to the knee or surrounding soft tissues (including skin) were consented. Participants completed an ACL-QOL questionnaire pre-operatively, were randomized intra-operatively, and returned for follow-up at 1.5-, 6-, 12 – and 24-months to trace altered area of skin sensation and complete an ACL-QOL questionnaire. The area of altered skin sensation was quantified with ImageJ (NIH) software. The intention-to-treat principle was applied and a student’s t-test was used for statistical analysis. (p< .05).

Results: An interim analysis of 25 patients with a follow-up of 6 – to 24-mo demonstrated that the VI group (79.1 ± 15.6 cm2) had a greater affected area than the OI group (10.9 ± 3.5 cm2), no difference in ACL-QOL scores was evident.

Conclusion: Based on the difference in morbidity between the two groups, and similar results in a previous study (2), OI incision for graft harvest is recommended.


Timothy R Daniels Roger Haene Rob Story Ellie Pinsker

Purpose: The treatment of large osteochondral lesions of the talus (OLT) remains a challenge. Fresh Osteo-chondral Allograft is a method that has been used for the treatment of larger lesions, with the advantage of transplanting living cartilage that is biologically attached to the subchondral bone. The purpose of this clinical series is to prospectively review the clinical and radiographic outcomes of patients that have undergone a Fresh Osteochondral Allograft.

Method: Between January 2003 and January 2007, 17 feet in 8 male and 8 female patients at a mean age of 35.8 (15–53) years underwent fresh osteochondral talar allo-grafting by a single surgeon. Data was prospectively collected, including preoperative and postoperative AOFAS, AOS, AAOS foot & ankle worksheets and SF-36 scores. Statistical analysis consisted of one tailed student T-test with alpha set a 5%. All patients were followed up clinically and radiographically by x-ray and CT scan.

Results: Average follow up was 3.2 (0.9–6.2) years. All scoring systems showed significant improvement postoperatively, except for AAOS shoe comfort scores, and the Mental Component Summary of the SF-36 questionnaire. The AOFAS score improved significantly (p=0.0001) from a mean score of 53.4 (30–71) to 86.3 (72–96). AOS pain scores improved significantly (p=0.0053) from a mean score of 45.4 (8.7–72.2) to 24.1 (4.2–58.9). AOS disability score improved significantly (p=0.0013) from a mean of 53.8 (7.8–77.3) to 25.9 (6.6 – 62.5). The AAOS foot & ankle core scale (standardized mean) improved significantly (p=0.0015) from a mean of 52.3 (21–81) to 80.1 (56–99). The AAOS foot & ankle core scale (normative score) improved significantly (p=0.0016) from a mean of 16.9 (−9 to 40) to 39.5 (20–55). The SF-36 Physical Component Summary improved significantly from a mean of 34.9 (24.2–43.8) to 47.3 (36.6–59.8). There was successful osseous graft incorporation in 16/17 feet (94%) verified on CT scan. Of the 16 grafts which had successfully incorporated, radiographic follow up showed 4/16 feet (25%) had signs of progressive OA and 3/16 feet (19%) had developed new osteolysis around the graft.

Conclusion: Although patients’ functional outcome can be substantially improved with the use of fresh osteochondral allografts the early radiographic findings are of concern with 43% demonstrating progression of arthritis or osteolysis of the graft during the process of graft incorporation.


George L Xenoyannis Jeff Yach

Purpose: Intra-articular screw penetration with the use of proximal humeral locking plates has a reported incidence in the literature of up 25%. It may occur early, due to an intra-operative unrecognized technical error, or as a result of late fracture collapse. This study was designed to demonstrate the “approach-withdraw” technique of intra-operative fluoroscopy which can be used to minimize the rate of early unrecognized intra-articular screw penetration.

Method: A radiographic review was undertaken of 37 patients with proximal humerus fractures fixed with either the PHILOS plate (Synthes, Westchester, Pennsylvania) or the Periloc proximal humerus plate (Smith and Nephew, Memphis, TN) by the senior author (JY) between 2002 and 2009. Intra-operative fluoroscopy was used in each case to ensure there was no intra-articular screw encroachment by visualizing each screw tip approach and then withdraw from the articular surface during live fluoroscopy as the shoulder was taken through a range of motion. Patients were then followed for an average of nine months with serial radiographs for post-operative intra-articular screw penetration, screw loosening, and maintenance of reduction. Maintenance of reduction was evaluated using the change in neck shaft angle and greater tuberosity to humeral height difference on the initial post-operative x-rays as compared to the x-rays at final follow-up.

Results: An average of six screws (range three to nine) was placed into the humeral head per patient. There was no incidence of intra-articular screw penetration on immediate post-operative radiographs. One patient had loss of reduction with a single screw breaching the sub-chondral bone and four screws loosening after a fall in the early postoperative period. The remainder of patients had no evidence of intra-articular screw penetration or screw loosening at last follow-up. One patient developed a non-union and had a subsequent reconstruction. The average change in neck shaft angle was four degrees (range 0° to 16°) and greater tuberosity to humeral head height difference was 1.9 mm (range 0 – 8.9).

Conclusion: The approach-withdraw technique is a useful intra-operative fluoroscopic test which may be utilized in the fixation of proximal humerus fractures to avoid unrecognized intra-operative screw penetration of the glenohumeral joint.


Johannes M Van der Merwe R. Cole Beavis Geoffrey Johnston

Purpose: Due to bed and resource constraints at the Royal University Hospital in Saskatoon, Saskatchewan, we have seen an increase in utilization of the day surgery program for acute Orthopedic traumatic injuries in ambulatory patients. The purpose of this study was to assess patient satisfaction with the Saskatoon Health Region Orthopedic trauma day surgery program by collecting data pertaining to wait-times, demographics, communication, coping skills at home and pain management.

Method: A patient-oriented questionnaire was devised and administered to eligible adult patients presenting for day surgery Orthopedic Trauma procedures over a three month period. Inclusion criteria included age greater than 18 and written english comprehension. Between July 12 and October 2, 2009, 45 patients consented to participate. The questionnaire was formulated to encapsulate all the potential concerns associated with the day-surgery program, which included expected wait-times, pain control, and communication between the orthopedic surgeon and the patient. Demographics and actual wait-times were obtained from hospital data.

Results: There was a marked discrepancy between the actual and anticipated waiting times for day surgery. However, 64% of the patients were still satisfied with the waiting times despite the difference. Seventy three percent of patients did not think that admission to hospital would lead to earlier surgery. There was an obvious difference in demographics with 53% of patients living outside city limits. Demographics played an important role in patient satisfaction. Patients living within the city limits had a better experience compared to patients living outside city limits. Patients did have difficulty managing at home. The overall satisfaction was 68% at the conclusion of the study.

Conclusion: Patients were overall satisfied with the day surgery program. We have identified several areas where we can improve. This involve better pain management, better communication and assessment of the bio-socioeconomic circumstances of patients. We will also have a lower threshold for admitting non residents of Saskatoon. We will relay a more realistic timeframe for surgery, as calculated in the study, to patients .


David W Sanders Sagar Desai Louis M Ferreira Joshua W Giles James Johnson

Purpose: Blocking screws placed adjacent to intramedullary nails supplement fixation in long bone fractures with a short proximal or distal segment. Clinically, blocking screws are placed using fluoroscopy, resulting in variability in screw placement. The clinical significance of the accuracy of screw placement is unknown. Recently, a targeted blocking screw device was developed, enabling precise placement of screws adjacent to the nail. The purpose of this study was to evaluate the mechanical effects of locking screws (LS) and targeted (TBS) and non-targeted blocking screws (NBS) in distal femur fractures.

Method: Sawbone® femurs were used to create a fracture model. Femoral sawbone specimens were osteotomized eight cm proximal to the knee joint and a two cm gap was created. Intramedullary nails were used for stabilization, including one proximal locking screw and varying the distal screw configuration for study purposes. Targeted blocking screws were inserted directly adjacent to the intramedullary device using the commercially-available targeting device. Non-targeted screws were inserted one screw diameter medial or lateral to the “ideal” position. Four study groups were created; group one consisted of TBS and two distal LS. Group two had TBS and one LS. Group three had NBS and two LS, and group four consisted of NBS and one LS. Specimens were subjected to a cyclic compression protocol along the mechanical axis of the femur. Applied load varied from 100 to 700 N in 100 N incremental staircase loading protocol. Load-displacement curves recorded construct stiffness. Fracture gap motion was measured with electronic calipers.

Results: Targeted constructs were stiffer at all load levels, and 10% stiffer overall. Differences were statistically significant at moderate load levels (Group one vs three, 400N and 500N, p< 0.05).

Conclusion: Targeted constructs were stiffer at all load levels despite Sawbones® undergoing significant deformation at the proximal femur, masking the relatively smaller differences in motion at the fracture site. A difference in sagittal motion was found between groups with one and two LS, independent of the position of blocking screws. In conclusion, targeted blocking screw constructs were stiffer at all load levels compared to non-targeted constructs. The number of LS was a factor in sagittal plane stability. This study suggests that using targeted blocking screws in distal femur fractures may reduce fracture motion and decrease post operative malalignment.


Mohit Bhandari Bernadette G Dijkman Jason W Busse Stephen D Walter

Purpose: Radiographic healing is a common outcome measure in orthopaedic trials and adjudication by outcome assessors is often conducted using only plain radiographs. We explored the effect of adding clinical notes to radiographs in the adjudication process of a pilot trial of tibial shaft fractures.

Method: Radiographic and clinical data from a multicenter clinical trial of 51 patients with operatively treated tibial fractures formed the basis of the study data. An independent adjudication committee of three blinded orthopaedic trauma surgeons evaluated radiographs for time to fracture healing. This committee then evaluated clinical notes associated with each radiographic follow up visit and were asked to either revise or maintain their initial impression. We calculated the proportion of time to healing consensus decisions that changed after evaluation of clinical notes. We further examined the contents of the clinical notes and its relative influence on the committee’s decisions.

Results: Forty-seven of 51 patients were determined to have radiographic evidence of healing during the trial follow-up period, and consideration of the clinical notes resulted in a change of 40% (19 of 47) of time to healing consensus decisions; however, revised decisions were equally likely to support an earlier or a later time to healing.

Conclusion: Addition of clinical notes changed the adjudication committee’s decision of radiographic fracture healing in a substantial number of cases. Our findings suggest that orthopedic trialists should consider the addition of clinical notes to adjudication material in studies of fracture healing.


Tudor V Tufescu Bryn Sharkey

Purpose: The purpose of this study is to provide an additional tool to determine the stability of AO 31A2 pertrochanteric hip fractures. This study is based on the lateral hip radiograph, which has been ignored in the current debate over stability.

Method: One-hundred and thirty-one patients were identified through medical records with a diagnosis of pertrochanteric hip fracture treated with sliding hip screw from 2003–2008. Thirty-nine patients had AO 31A2 hip fractures, cross-table lateral injury films, intra-operative fluoroscopy and follow-up films. Only 23 had follow-up films beyond discharge. The landmarks of interest were angulation and translation between the femoral shaft and neck on cross-table lateral injury films. The neck was defined in three ways: the anterior cortex, two key points in the anterior cortex and the neck bisector. The most consistent measure was used. Translation of the neck was measured as a percentage of the shaft diameter. Measurements were taken by two blinded researchers with different levels of experience. Film sequence was randomized. The primary outcome was shortening of the sliding hip screw greater than one centimetre. This is the exact midpoint between 0.61 centimetres, which is not associated with reduced patient mobility, and 1.34 centimetres which is associated with reduced patient mobility, as described by Muller-Farber. The hip screw was measured from its tip to the point it enters the barrel. The diameter of the hip screw was known and provided scale. The measurement from intra-operative fluoroscopy films with the leg in traction, represented zero shortening.

Results: The average follow up was 190 days. Using the neck bisector to measure angulation was most consistent (95% of measurements available versus 89% and 88% with other methods). More than 30° angulation and/or 30% translation on the lateral predicted shortening greater than one centimetre with 91% specificity and 33% sensitivity. The average shortening in this group was 1.6 centimeters, which is greater than shortening associated with reduced patient mobility (1.34 centimeters). Agreement between two researchers was 91% and considered “substantial” (kappa 0.71) as per Landis and Koch criteria.

Conclusion: This is a highly specific and reproducible tool to detect a subset of AO 31A2 hip fractures which acquire unwanted collapse if treated with a sliding hip screw. This information adds clarity to the debate over stability of some AO 31A2 fracture cases, at no additional cost for the surgeon and facility. The “30/30 rule” (30° angulation and 30% translation) should not be used in isolation due to low sensitivity. Other factors may affect shortening, such as the degree of comminution and the antero-posterior film should still be considered.


R Mervyn Letts Atef Hassan

Purpose: To assess the efficacy of the Taylor Spatial Frame in the correction of rigid long standing foot deformities in older children.

Method: Children presenting with rigid longstanding foot deformities were fitted with a Taylor Spatial Frame (TSF) utilizing specialized small foot rings. Prior to surgery an operative plan was devised including soft tissue release and osteotomies usually consisting of a curved midfoot osteotomy and a dome shaped hind foot osteotomy. About 30% correction was obtained at surgery and held with the TSF. Postoperatively a computerized program of correction over a period of 8 weeks was calculated for each foot beginning 5 days after surgery and including an initial lengthening at each osteotomy site of 1 cm.

Results: A total of eight feet have been corrected utilizing this technique with the TSF. All feet have been successfully returned to a plantigrade position enabling the child to don normal footwear. Ankle-foot orthosis are utilized for one year following surgery. Although the feet are stiff none are painful and all children arev fully ambulatory and weight bearing. All have at least 10 degrees of ankle motion which is improving with time. Families have been very pleased with the improved anatomical appearance of the feet as well as the child’s ability to use normal footwear.

Conclusion: The Taylor Spatial Frame is an efficient and safe method to effect excellent correction of a rigid club foot deformity in combination with osteotomies and soft tissue releases of the foot.


Krista Goulding Rudolf Poolman Emil H Schemitsch Mohit Bhandari Brad Petrisor

Purpose: To determine the effect of reamed versus non-reamed intramedullary (IM) nailing of femoral diaphyseal fractures on the rates of non-union and acute respiratory distress syndrome (ARDS).

Method: We searched the online databases of OVID, MEDLINE, EMBASE, PubMed, and the Cochrane collaboration for randomized clinical trials (RCT) from 1998 to 2009. Additional studies were identified by hand searches of major orthopaedic journals, reference lists of eligible studies, SCISEARCH, and title reviews of presentations from major orthopaedic trauma meetings. Inclusion criteria were trials evaluating the effect of reamed versus nonreamed closed interlocked intra-medullary nailing of femoral diaphyseal fractures on the rates of nonunion or acute respiratory distress syndrome (ARDS) in skeletally mature adults. Exclusion criteria included patients with pathologic fractures, skeletally immature patients, as well as observational and other non-randomized studies.

Results: Seventy-two citations were initially identified out of 1,147 studies. 6 studies matched all eligibility criteria as assessed by three independent reviewers. A total of 941 patients with 956 femoral diaphyseal fractures treated with intramedullary nailing met the eligibility criteria. The relative risk of non-union (four trials, n= 456 patients) was 0.29 [95% confidence interval (CI), 0.14 to 0.57; p< 0.00001] (ie. a 70% relative risk reduction of nonunion) in favour of a reamed intramedullary nail There was no significant difference in the rates of ARDS following reamed or non-reamed nailing, relative risk for ARDS (two trials, n=397) 1.10 [95% CI, 0.27 to 4.54, p=0.18].

Conclusion: The study suggests that reamed intramedullary nailing of femoral diaphyseal fractures significantly reduces the risk of non-union as compared to nonreaming. The risk of ARDS was not statistically significant between groups; however there was a slight trend towards ARDS iwith reamed IM fixation.


Mohit Bhandari David D Thompson Irina V Kaplan Vishwas M Paralkar Gojko Buljat David Sanders John Schwappach Slobodan Vukicevic

Purpose: Identification of novel therapeutics to accelerate acute fracture healing remains critical. A prostaglandin EP-2 receptor agonist (CP-533,536) has demonstrated acceleration of fracture healing in preclinical models.

Method: In a phase II randomized, blinded, placebo-controlled trial the efficacy of a single local injection of three doses of CP-533,536 (0.5mg, 1.5mg and 15mg) was compared to both placebo and a standard of care arm in patients with closed tibial shaft fractures treated with reamed inter-locked intramedullary nails. Patients were followed at two week intervals to six months with a final evaluation at one year. Fracture healing was independently adjudicated by a radiologist panel and an orthopedic surgeon panel.

Results: Ninety-nine patients were enrolled ranging in age from 17–76 years. Baseline characteristics were comparable across treatment groups. No statistically significant differences in median healing time between any of the CP-533,536 treatment groups and placebo were observed based on radiology panel assessment, however significant differences were demonstrated by an orthopedic panel. At weeks eight, 10, 12, 14 and 16 a higher percentage of subjects in the CP-533,536 1.5 and 0.5 mg groups were considered healed compared to the placebo and the 15 mg groups by the orthopedic panel assessment. Moreover, the CP-533,536 – 0.5 mg group showed a statistically higher (p≤0.05) mean radiographic healing score than placebo treated group at weeks eight, 14, 16, 18, and 24.

Conclusion: CP-533,536 demonstrated accelerated healing in patients with acute tibia fractures by an orthopedic panel. Confirmatory trials are required to assure validity of the observed treatment effects.


Sameh El Sallakh Mohamed Mohamed Roony Mifsud

Purpose: Whiplash injury occurs due to motor vehicle accidents has its long term consequence, nevertheless very little is written about its long-term follow up. The aim of the study is to find out the long-term follow up of Whiplash injury and the factors affecting the long-term follow up

Method: It is a retrospective study which was done in Russells Hall Hospital in the west midland in UK. 64 patients were selected in this study. Only 54 patients were replied. An inclusion criterion was Whiplash injury due to RTA in years 1995, 1996 and 1997. Initial examination was performed 5.6 +/ – 4.5 days after trauma, and follow-up examinations 3, 6, 12, and 24 months. Exclusion criteria were any cervical spine bony injury, associate head injury and poly-trauma patients. The outcome measures used for assessment are SF36, Whiplash Disability Questionnaire score WDQS, and questions to cover their present symptoms, work circumstances before and after the injury, current and previous treatment

Results: In our study we found that the time it takes for the patient’s symptoms to resolve varies, it took less than 6 weeks in 4 patients, between 6 weeks to 3 months in 10 patients, between 6 months to 1 year in 15 patients and more than one year in 3 patients. The average follow up time was 10.3 years. Our results did show these figures: 22 patients were still symptomatic 10 years after injury, 18 still complaining of pins & needles, 13 still having frontal headache and 7 having occipital headache. Headache was one of the symptoms which annoyed Whiplash injury patients. Headaches following Whiplash injuries were occipital, frontal or generalised. Headache was usually of Muscular contraction type, often associated with greater occipital neuralgia. 16 patients still had treatment in the form of pain killers or physiotherapy. The mean WDQS was less than 20 in 38 patients. The mean WDQS in patients with low back pain was 29.23 and for those without back pain were 12.53. In the smokers the mean whiplash score was 32.2. In the non-smokers the Whiplash score was 17.93. The mean WDQS in those who do not drink alcohol was 26.73 and in those who drink alcohol were 16.58.

Conclusion: Whiplash injury patients have long term residual symptoms mainly pins & needles as well as headache and dizziness. Claiming compensation is a bad prognostic factor on the long-term outcome of Whiplash injury patients. Drinking alcohol, Gender, BMI, treatment given after the initial injury and smoking have no effect on the long-term outcome of these injuries. Age & Low back pains are bad prognostic factors. Whiplash Disability Questionnaire score, SF 36 (for body pain) and time for symptoms to be relieved are sensitive outcome measures to assess those injuries.


Babak Shadgan Luke W Harris Darlene Reid Scott K Powers Peter J O’Brien

Purpose: Several variables related to tourniquet (TQ) inflation contribute to ischemic muscle injury. Among these the duration of ischemia has been identified as a primary factor. The purposes of this study were to investigate the following during and after TQ-induced ischemia during orthopedic trauma surgery:

muscle oxygenation changes measured by near infrared spectroscopy (NIRS);

muscle protein oxidation; and

correlations between muscle oxygenation / hemodynamics and oxidative changes.

Method: Consented patients aged 19–69 yrs (n=18) with unilateral ankle fracture requiring surgery at our institution were recruited. A pair of NIRS probes was fixed over the midpoint of the tibialis anterior muscle (TA) on both the injured and healthy legs. A thigh TQ was applied to the injured leg and inflated to 300 mmHg. Using the NIRS apparatus coupled to a laptop with data acquisition software, changes in oxygenated (O2Hb), deoxygenated (HHb), and total hemoglobin (tHb) levels in the TA of both legs were measured before and during TQ inflation, and after release until values returned to baseline. PRE surgical biopsies were collected from the peroneus tertius muscle (PT) immediately after TQ inflation and incision. POST biopsies were collected from the same PT immediately before TQ deflation. Oxidation of PT myosin, actin, and total protein was quantified using Western blot analysis of 4-hydroxynonenal (4-HNE) modified proteins. Data are reported as mean±SD.

Results: In PRE biopsies compared to POST biopsies there were large and statistically significant increases in the PT content of 4-NE modified myosin (174.4±128%; P< 1×10-6), actin (223.7±182%; P< 5×10-9), and total protein (567.5±378%; P< 5×10-7). There was a greater increase in PT protein oxidation in male subjects than in female subjects (50.8% difference; P< 0.05). In the TA of the fractured side, there were moderate to strong linear correlations between total protein oxidation and: the relative change in tHb (r=−0.704) and O2Hb (r=−0.415) during the period of TQ inflation and the rate at which the muscle became reoxygenated following TQ release (r=0.502). There was no relationship between muscle protein oxidation and TQ time, nor between muscle protein oxidation and age of patients.

Conclusion: TQ-induced muscle ischemia for 21 to 74 min during lower extremity surgery leads to oxidative muscle injury as measured according to myofibrillar contractile protein oxidation. Importantly, we observed that when the TQ was “leaky,” local increases in muscle tHb were associated with a lower magnitude of protein oxidation, however, when local decreases in muscle O2Hb were observed, perhaps due to local blood loss below the TQ, more oxidative changes resulted. Intriguingly, gender appeared to influence the extent of muscle oxidative injury, but age did not. Surprisingly, there was no significant correlation between muscle oxidative injury and the TQ-induced ischemia interval.

FUNDING: MSFHR, COF, BCLA.


Brett Dunlop Laurie Mclaughlin Charlie Goldsmith

Purpose: Uncertainty around back pain management results in large volumes of patients with back related complaints being referred to orthopaedic surgeons for direction. The vast majority of these referrals are non surgical leading to unacceptable wait times (T1) across Canada. This reservoir delays not only those who are disabled with problems requiring a surgical remedy but also those who only require direction to appropriate conservative care. Physiotherapists with advanced training in orthopaedics possess skills in musculoskeletal interview, exam and Orthopaedic residents on the other hand must acquire spine specific skills in interview and exam, interpretation of radiographic exams, surgical decision making as well as surgical technique in a 2–3 month residency rotation. Our question was „Can an Experienced Physiotherapist Become Proficient in Triaging for Surgically Appropriate Patients After a 2–3 month „Residency „.

Method: Following a 3 month clinical residency an experienced physiotherapist and a spine surgeon independently interviewed, physically examined and reviewed diagnostic imaging of 31 patients. It was then independently concluded whether the patients were candidates for surgical treatment, required conservative management or whether further investigations were necessary to make the final determination. The level of agreement was calculated using Chance Corrected Agreement or Kappa values. Operational definitions were reviewed and a second group of 29 patients were assessed.

Results: The initial Kappa score was .68 (considered good clinical agreement) and the final Kappa score was 0.84 (considered virtually interchangeable).

Conclusion: A 3 month period can prepare an experienced orthopaedic physiotherapist to triage a waiting list for surgical candidates. The therapist can add value through being better prepared to direct conservative options. Expediting triage will facilitate the right person getting to the right intervention within a reasonable time frame. Addressing the backlog of referrals will also help identify the magnitude of surgical need.


Paul B Bishop David Brunarski Charles Fisher

Purpose: Screening patients for appropriate treatment is a key component of an effective hospital-based spine service. To date, a standardized and validated method for carrying out this process has not been established. In particular, studies to determine who should staff these screening services, their safety and reliability have not been reported. The goal of this study was to determine the inter-examiner reliability of patient screening assessments by Chiropractors and Spine Physicians.

Method: Prospective observational cohort. 50 consecutive patients with acute lower back pain < 16 weeks duration (QTFSD I, II) referred to a quaternary care hospital spine program were studied. The inter-examiner agreement for 10 physical examination procedures and 5 red flag conditions was calculated using the Cohen’s kappa value. Patients were assessed by one of three spine physicians and one of three Chiropractors for normal or abnormal deep tendon reflexes, nerve root tension signs; lower extremity sensory / motor deficit; muscle atrophy; Schober’s test and depth of lordosis. Any history suggestive of cauda equina, fracture, infection, spinal malignancy or progressive neurological deficit was recorded. The results were compared where applicable, with previously published kappa values for lower back examination procedures.

Results: Four of the 50 patients had one or more red flag conditions with an inter-observer reliability of 0.96; 8 of 10 physical examination procedures had a kappa value of > 0.9; the kappa for + sensory deficit was 0.66 and for + femoral nerve stretch test was 0.47.

Conclusion: In this pilot study, initial patient screening assessments carried out by Chiropractors and Spine Physicians had high inter-observer reliability in 8 of the 10 examination procedures tested and were superior to previously reported multidisciplinary inter-observer kappa values.


Timothy R Daniels Murray John Penner D. Joshua Mayich Michael Bridge

Purpose: The global utilization of total ankle arthroplasty (TAR) has been increasing over the past decade; however there are a limited number of published prospective studies assessing intermediate and long term outcomes. The purpose of this clinical series is to prospectively review the mid-term clinical and radiographic outcomes of the Scandinavian Total Ankle Replacement (STAR) performed at two Academic Canadian University Centres.

Method: Between 1998 and 2005, 113 STARs were implanted into 99 patients at two Canadian centres. Prospective clinical and radiographic follow-up was performed. Validated and non-validated outcome questionnaires consisting of the AAOS foot and ankle questionnaire (a composite questionnaire made up of unaltered versions of the SF-36), AOFAS Hindfoot score, Foot Function Index (FFI), Ankle Osteoarthritis Scale (AOS) were completed in one arm (63/113 implanted TARs). In the other arm, (50/114) the patients were followed retrospectively with the same measures. Both groups had prospective radiographic follow-up using measures described by Wood et al.

Results: The average follow-up for both groups was 46.3 ± 17.6 months (or 3.8 years). Of the 113 implanted STARs, 33 (29.2%) required a re-operation. Of those, 20 (17.7%) went on to be revised. Six patients had repeat revision operations for a total of 26 revision operations. Of the 26 revision operations 14 (54%) were polyethylene liner exchanges, and 12 (46%) were revision of the metallic components. The median time to revision was 39.5 months. Three prosthesis (2.6%) went on to have a deep infection of their STAR. All three were effectively managed without requiring explantation of the STAR. One patient had infection in their revision IM Nail. Of the 113 initially implanted prostheses, 101 (89.3%) of the original TARs remained implanted at the conclusion of the study. Sustained benefit, across questionnaires, from the STAR was observed to persist to final follow up. 115/116 (99%) ankles followed showed evidence of osteolysis at the last STAR follow-up. The osteolysis was found to occur more commonly around the talar component, but occurred, for the most part, in a recognizable pattern around both the talus and the tibia. No significant differences between the two centers in pre-operative or intra-operative data were identified.

Conclusion: The STAR, in the mid-term, shows acceptable survival and revision rates. There are, however, some concerning findings on radiographic follow-up. It appears, upon initial investigation, that initial component position may be a factor that predicts concerning radiographic changes. Further investigation is required to substantiate this.


Melissa Nadeau M Patricia Rosas Rosas Arellano Kevin Gurr Stewart I Bailey Brian Taylor Ruby Grewal Kirk Lawlor Christopher S Bailey

Purpose: Claudication is a common complaint of elderly patients. Lumbar spinal stenosis (LSS) and peripheral arterial disease (PAD) are the two main etiologies, producing neurogenic and vascular claudication respectively. Physicians initially diagnose claudication based on a “typical” symptom profile. The reliability of this symptom profile to accurately diagnose LSS or PAD as a cause of claudication is unknown, leading to the potentially unnecessary utilization of expensive and overly sensitive imaging modalities. Furthermore, clinicians rely on this symptom profile when directing treatment for patients with concurrent imaging positive for LSS and PAD. This study evaluates the reliability of various symptom attributes, which classically have characterized and differentiated the two.

Method: Patients presenting at a tertiary care center’s vascular or spine clinics with a primary complaint of claudication were enrolled in the study. Diagnosis of either LSS or PAD was confirmed with imaging for each patient. They answered 14 questions characterizing their symptoms. Sensitivity, specificity, positive and negative likelihood ratio (PLR and NLR) was determined for each symptom attribute.

Results: The most sensitive symptom attribute to rule out LSS is “triggering of pain with standing alone” (0.96). Four symptom attributes demonstrated a high PLR and three had low NLR for diagnosing neurogenic claudication (PLR= 3.08, 2.51, 2.14, 2.9; NLR=0.06, 0.29, 0.15). In vascular patients, calf symptoms and alleviation of pain with simply standing had a high PLR and NLR (PLR= 3.08 and 4.85; NLR= 0.31 and 0.36).

Conclusion: Only four of 14 “classic” symptom attributes are highly sensitive for ruling out LSS, and should be considered by primary care physicians before pursing expensive diagnostic imaging. Six symptom attributes should be relied upon to differentiate LSS and NLR. Numbness, pain triggered with standing alone, located in the buttock and thigh, and relieved following sitting, are symptom attributes which reliably characterize neurogenic claudication.


Mark Glazebrook Patricia Francis

Purpose: To compare the clinical outcomes of patients surgically treated for end stage ankle arthritis using total ankle arthroplasty or ankle arthrodesis.

Method: This is a single center clinical outcome study of the surgical treatment of patients with end stage ankle arthritis (n=81) using an ankle arthrodesis or total ankle arthroplasty. Clinical outcome was assessed using health related quality of life (SF36v2) and joint specific (Ankle Osteoarthritis Scale, American Orthopedic Foot and Ankle Hindfoot Scale and the AAOS Foot and Ankle Baseline Questionnaire(version 2000)) outcome scores. Complications were recorded as well.

Results: Preoperatively, all patients had significant physical and psychological morbidity. There was a significant improvement in the health related quality of life and the joint specific clinical outcome scores at 1, 2 and 3 years follow up (p-value.05) Complications included 5 (10%) non union, in the ankle arthrodesis cohort and 2 (6.7%) revisions for aseptic loosening in the total ankle arthroplasty cohort.

Conclusion: The results of this study indicate that surgical treatment of end stage ankle arthritis with ankle arthrodesis or total ankle arthroplasty equally improve clinical outcome in the short term with acceptable and similar complication rates.


Alexandre Denault Ish Bains Ken Moghadam Richard W Hu Ganesh Swamy

Purpose: Odontoid fractures are the most common cervical spine injuries in the elderly. Although octogenarians are the fastest growing age group, limited data exists on the natural history after they sustain odontoid fractures. Published mortality rates vary greatly, but are high enough to elicit comparisons to post-hip fracture mortality. It has also been suggested that halo-vest immobilization independently predicts mortality.

Method: All traumatic odontoid fractures (type II or III) seen at our institution between 1996 and 2008 were identified and only patients who were ≥ 80 years of age were selected. A retrospective chart review was performed for injury characteristics, comorbidities, hospitalization details, treatment regimen and documented complications. Patients were stratified using the Charlson comorbidities index. The primary outcome was mortality at one year and was identified using a provincial database.

Results: 72 cases were identified. Median age was 86 years (range 80 to 102). Patient treatment regimens included rigid neck collar, Halo vest orthosis, surgery or a combination thereof. 31% percent of the cohort (22 patients) was treated by Halo vest immobilization. Overall 1-year mortality rate was 15% (n=11) with only 1 Halo vest patient dying during this period. The majority of deaths (9 / 11) occurred in first 2 weeks following the injury.

Conclusion: Mortality rate in the octogenarian population sustaining an odontoid fracture is high and approaches the 1-year hip fracture mortality rate. The utilization of a Halo vest was not associated with increased mortality rate in our study. Optimal treatment regimens, and strategies to minimize morbidity, particularly in the early post-injury phase, necessitate further study.


Rajiv Gandhi Kenneth Woo Yoga R Rampersaud

Purpose: MetS has been shown to be a risk factor for chronic diseases such as cardiovascular diseases (CVD), including myocardial infarction and stroke, and dementia. Moreover, the risk factors that make up the MetS (central obesity, diabetes, high blood pressure, and dyslipidemia) have also been demonstrated to have independent relationships to degenerative joint disease. The relationship between the metabolic factors and spine OA have been examined by few, however the predictive value of MetS on the incidence or prevalence of this disease has not been studied. In this study, we asked whether the prevalence of spinal OA increases with the number of MS risk factors.

Method: We reviewed data from a single surgeon, high volume, spine surgery practice between the years of 2002–2007. Demographic data including the components of the MetS risk factors were collected. Prevalent severe OA was defined as degenerative spondylolisthesis or cervical or lumbar stenosis causing neurologically based symptoms, and early OA as those with lumbar and cervical spondylosis causing axial pain only. Logistic regression modeling was used to determine the odds (adjusted for age and sex) of having severe spine OA with an increasing number of the MetS risk factors.

Results: In our cohort of 1502 patients, there were 839/1502 (55.9%) patients defined as severe spinal OA and 663/839 (44.1%) patients with early OA. Those with severe spinal OA were significantly older, with a greater percentage of females, and had a greater BMI than those with early spinal OA (p < .05). The prevalence of severe spinal OA varied across groups defined by the number of MetS risk factors: 353/748 (47.2%) in those with 0 MetS risk factors, 236/392 (60.2 %) in those with 1 MetS risk factors, 148/228 (64.9 %) in those with 2 MetS risk factors, 76/104 (73.1 %) in those with 3 MetS risk factors, and 26/30 (86.7 %) in those with all 4 MetS risk factors. The overall prevalence of MetS was 30/1502 (2.0%), 26/839 (3.1%) in the severe OA group and 4/663 (0.6%) in the early OA group.(p= .001) Logistic regression modeling showed the odds of having severe spinal OA increased with an increasing number of MetS risk factors relative to having no MetS risk factors. Those patients having defined as MetS had almost a 4 times greater odds of having severe spinal OA as compared to those with no MetS risk factors, adjusted for age and gender [OR 3.9,(1.4, 11.6), p= .01].

Conclusion: The components of MetS are more prevalent in those with severe spinal OA causing neurological symptoms compared to those with spondylosis causing axial pain. Future work should examine for an association between MetS and incident OA.


Emily R Dodwell Julius Gene Latorre Emilio Parisini Elisabeth Zwettler Divay Chandra Kishore Mulpuri Brian Snyder

Purpose: Non-steroidal anti-inflammatory drugs (NSAIDs) are powerful analgesics, frequently used for post-operative pain control. However, concerns regarding the potential deleterious effects of NSAIDs on bone healing have compelled many physicians to avoid NSAIDs in patients with fractures, osteotomies, and fusions. The purpose of this study was to systematically review and meta-analyze the best clinical evidence regarding the effects of NSAIDs on bone healing.

Method: We performed a literature search for studies of fracture, osteotomy or fusion patients with NSAID exposure, and non-union as an outcome. Data on study design, patient characteristics and risk estimates were extracted. Pooled effect estimates were calculated. Study inclusion results were checked for evidence of publication bias. Metaregressions were performed to assess the impact of age, smoking, and study quality on reported risk of non-union.

Results: Seven spine fusion and four long-bone fracture studies were included. A significant association between lower quality studies and higher reported odds ratios for non-union was identified. When only higher quality studies were considered, seven spine fusion studies were analyzed, and no statistically significant association between NSAID exposure and non-union was identified (OR=2.2, 95%CI:0.8, 6.3). No statistically significant association was found in sub-analysis of patients exposed to high dose IV/IM ketorolac (OR=2.0, 95%CI:0.4, 11.1), low dose IV/IM ketorolac (OR=1.2 95%CI:0.3, 4.5), or standard oral NSAIDs (OR=7.1, 95%CI:0.1, 520). In sub-analysis of the four most clinically relevant studies of adult spine fusion patients with well defined peri-operative NSAID exposure, no statistically significant association was found between NSAID exposure and risk of non-union (OR=0.8 95%CI:0.4, 1.4).

Conclusion: Studies on NSAID exposure in long-bone healing settings were of lesser quality than studies in the spine fusion setting. Within the spine literature we could not demonstrate any increased risk of non-union with NSAID exposure. Randomized controlled trials (and meta-analyses of such trials) on the impact of standard NSAID and COX-2 inhibitor exposure in spine and long-bone fracture, fusion and osteotomy populations are warranted to confirm or refute the findings of this meta-analysis of observational studies.


Douglas L Hill Eric C Parent Edmond Lou Marc J Moreau James K Mahood Douglas M Hedden

Purpose: Rigid full-time braces are the most common non-surgical treatment for adolescents with moderate severity of scoliosis and demonstrated growth remaining. The Scoliosis Research Society (SRS) has established guidelines on which patients with adolescent idiopathic scoliosis (AIS) should be offered brace treatment. This study surveyed Canadian surgeons on the demographics of patients with scoliosis attending specialty clinics and for their protocols for prescribing braces.

Method: An on-line survey of 41 questions was developed to document patient profiles and surgeon protocols for prescribing braces. Surgeons also selected whether they would recommend a brace in females with AIS based on a combination of three levels of maturity, with six levels of curve severity, and whether or not the curve was progressive. The survey was administered between July and November 2008 to the 30 paediatric spine surgeon members of the Canadian Paediatric Spinal Deformities Study Group. After one reminder, the response rate was 70% (21/30), representing 12 Canadian spine centres.

Results: The average age of referral to the scoliosis clinic was 11–12 years (10 of 20 respondents) and 13–14 years (nine of 20 respondents). Most (81%) of the centers required radiographs prior to the first clinic visit. All surgeons recommended bracing, but there was broad variation on who they considered should be braced, with three to twenty six of the 36 potential scenarios defined by maturity, progression, and curve severity variables selected. This high variability was also observed among surgeons in the same spine centre. All considered parental or family issues and patient acceptance when recommending a brace. Age and curve severity were criteria for bracing; skeletal maturity was the primary criteria for discontinuing bracing. The majority (81%) of braces prescribed were rigid full-time braces followed by rigid night-time braces (14%). Weaning was common (76%), but protocols varied. Detection of curve progression increased the likelihood of bracing for curves 80% agreement on bracing. Braces were not recommended by > 50% of respondents for females with less than 1 year growth remaining regardless of progression or curve size.

Conclusion: In spite of SRS guidelines and general agreement that braces are effective, there is little agreement among surgeons on which females with AIS should receive brace treatment. The likelihood that a female with AIS will be prescribed brace treatment primarily depends on surgeon brace prescription patterns, rather than actual curvature of the spine.


John Street Christian DiPaola Davor Saravanja Luca Boriani Michael Boyd Brian Kwon Scott Paquette Marcel Dvorak Charles Fisher

Purpose: There is very little evidence to guide treatment of patients with spinal surgical site infection (SSI) who require irrigation and debridement (I& D) with respect to need for single or multiple I& D’s. The purpose of this study is to build a predictive model which stratifies patients with spinal SSI to determine which patients will go on to need single versus multiple I& D.

Method: A consecutive series of 128 patients from a tertiary spine center (collected from 1999–2005) who required I& D for spinal SSI, were studied based on data from a prospectively collected outcomes database. Over 30 variables were identified by extensive literature review as possible risk factors for SSI, and tested as possible predictors of risk for multiple I& D. Logistic regression was conducted to assess each variable’s predictability by a “bootstrap” statistical method. Logistic regression was applied using outcome of I& D – single or multiple as the “response”.

Results: 24/128 patients required multiple I& D. Primary spine diagnosis was approximately represented by ¼ trauma, ¼ deformity, ¼ degenerative and ¼ oncology/inflammatory/other. Six predictors: spine location, medical comorbidities, microbiology of the SSI, presence of distant site infection (ie. UTI or bacteremia), presence of instrumentation and bone graft type, proved to be the most reliable predictors of need for multiple I& D. Internal validation of the predictive model yielded area under the curve (AUC) of .84

Conclusion: Infection factors played an important role in need for multiple I& D. Patients with +MRSA culture or those with distant site infection such as bacteremia with or without UTI or pneumonia, were strong predictors of need for multiple I& D. Presence of instrumentation, location of surgery in the posterior lumbar spine and use of non-autograft bone predicted multiple I& D. Diabetes also proved to be the most significant medical comorbidity for multiple I& D.


Paul B Bishop Charles Fisher Jeff Quon Marcel Dvorak

Purpose: Clinical practice guideline (CPG) concordant treatment (Ctx) has been shown to be more effective than CPG discordant care (Dtx) in a heterogeneous cohort of patients with acute lower back pain (ALBP). However, patients with underlying spine pathology (e.g. stenosis, disc degeneration, facet joint arthropathy) or without identifiable spine pathology may all present solely with ALBP. At present, it is unknown if underlying spine pathology influences the outcome of Ctx. The purpose of this study was to determine if Ctx is more effective than Dtx in patients with differing underlying spine pathology who present with ALBP.

Method: A Two-arm, randomized control trial with stratified analysis. Inclusion: Ages 19–59; QTFSD I, II ALBP < 4 weeks. Exclusion: “Red Flag” conditions, comorbidities contraindicating Ctx. The primary outcome was the difference between Ctx and Dtx Roland Morris Disability (RDQ) scores at 16 weeks post baseline between study groups. Secondary outcomes: differences in Bodily Pain (BP), Physical Functioning (PF) SF-36 domain scores at 16 weeks. Patients were assessed by a spine physician and randomized to Ctx or Dtx. Patients were stratified on the basis of CT or MRI evidence of:

spinal stenosis;

disc degeneration;

facet joint arthropathy; or

no identifiable pathology.

Hospital / University Ethics approval was obtained.

Results: Eighty-eight patients were recruited; 39 in Ctx & 38 in Dtx group completed the study. Baseline prognostic variables were evenly distributed between groups. Outcomes: mean difference in 16 week RDQ, BP and PF scores between Ctx and Dtx was statistically greatest in group 4 (p< 0.001). There was no significant clinical improvement in RDQ, BP or PF scores in either the Ctx or Dtx in group 2.

Conclusion: Ctx was more effective than Dtx in patients with no identifiable spine pathology and ineffective and equivalent to Dtx in patients with underlying disc degeneration.


Michael G Zywiel Yona Kosashvili Allan E Gross Oleg Safir Dror Lakstein David Backstein

Purpose: The literature regarding the outcome of total knee arthroplasty following distal femoral varus osteotomy is limited. The largest published series to date of eleven such patients suggested that medio-lateral constrained implants are commonly required as ligament balancing is difficult. This study presents mid-term outcomes of patients treated with total knee arthroplasty following distal femoral varus osteotomy at a single center.

Method: Twenty-two consecutive distal femoral varus osteotomies (21 patients) converted to total knee arthroplasties were reviewed at a mean follow-up of five years (range, two to 14 years). The mean duration between osteotomy and conversion to arthroplasty was 12 years (range, three to 21 years). In 14 patients (15 knees) the underlying etiology for the femoral osteotomy was primary knee osteoarthritis with valgus deformity, while in seven patients the procedure was performed to unload a fresh osteochondral allograft of either the lateral tibia (five patients) or femur (two patients). It is the authors’ routine to use posterior stabilized implants were used in all total knee arthroplasty surgeries. Femoral stems were used in six knees in which the bone quality was clinically determined by the surgeon to be sufficiently deficient to predispose to periprosthetic fractures, while the remaining sixteen knees were treated with unstemmed components. Modified knee society scores were used to evaluate the clinical outcomes preoperatively and at most recent follow-up.

Results: The mean knee society knee and function scores in surviving knees improved from 50 points (range, 10 to 75 points) and 50 points (range, 30 to 70 points) pre-operatively, to 91 points (range, 67 to 100 points) and 64 points (range, 50 to 70 points) at final follow-up, respectively. The mean arc of motion improved from 94 degrees (range, 70 to 115 degrees) to 114 degrees (range, 90 to 130 degrees). Two patients underwent revision arthroplasty for polyethylene wear and component loosening at eight and 11 years following the index arthroplasty, respectively. There were no fractures, infections or wound complications.

Conclusion: Total knee arthroplasty following distal femoral varus osteotomy reliably decreases pain and improves knee function. Standard posterior stabilized components provide satisfactory stability after appropriate ligamentous balancing, without the need for stemmed or highly constrained components in the majority of patients.


Sanket Diwanji Jean-Michel Laffosse Martin Lavigne Pascal-André Vendittoli

Purpose: Even with modern ancillary and good surgical experience, rotational implant positioning is sometimes sub-optimal, leading to poor results. Except for obvious cases with patellar instability, the symptoms are often vague and non-contributive to the diagnosis of failure. This is why implant malpositioning and particularly malrotational postioning remain an underestimated cause of failure after primary total knee arthroplasty (TKA). We report our experience with TKA revision for rotational malpositioning.

Method: We retrospectively assessed the results of TKA revisions in 22 knees for malrotational positioning. In all cases, malrotational implant positioning was confirmed by CT-scan according to Berger’s protocol.

Results: Mean age was 66 years (47–74) at the time of the primary TKA. After the index procedure, all patients presented early anterior knee pain with patellar instability (tilt and subluxation in ten cases, and permanent patellar dislocation in two cases). Malrotational positioning predominated on the tibial component with mean 23° internal rotation. Mean cumulative malrotation (tibial plus femur) was 22° internal rotation. All but four patients underwent femoral and tibial component revision. In two cases, only the tibial component was revised, and in two other cases, isolated transposition of the anterior tibial tuberosity was carried out. One was a failure, and finally underwent a successful full revision. At a mean follow-up of 30 months (12–60), we noted significant functional outcome improvement. One patient, who underwent a patellectomy previously at the index TKA procedure, had persistant anterior knee pain. No patient presented patellar instability.

Conclusion: The diagnosis of implant malrotational positioning is sometimes difficult. The most common errors are tibial component positioning. In case of suspicion of malrotational positioning, protocolized CT-scan allows quick and simple diagnosis. If the malrotation is confirmed, TKA revision should be performed upon patient disability and severity of the symptoms. It is important not to delay the surgery, particularly in cases of patellofemoral dislocation because of the risks of developing soft tissue contractures resulting in a more difficult revision procedure.


Richard W McCalden Robert B Bourne Kory D Charron Steven JM MacDonald Cecil H Rorabeck

Purpose: The Genesis II total knee arthroplasty system was introduced in 1996 as the next evolution in TKR design characterized by “built-in” femoral external rotation and improved trochlear design to optimize patellar tracking and femoral/tibial kinematics, as well as a polished tibial base plate and ethylene-oxide sterilized polyethylene to minimize wear. The purpose of this prospective study was to evaluate the long-term (minimum 10 year) clinical and radiographic results and survivorship of this novel TKA implant system.

Method: Between 1996 and 1999, 478 Genesis II Primary TKRs were implanted and followed prospectively in 414 patients (mean follow-up 11.25±1.11 years). Diagnosis at index surgery included: 94% osteoarthritis, 5% inflammatory arthritis, 1% other diagnoses. Average age at index TKR was 68 years (range 38 to 93 years). There were 149 posterior cruciate retaining (31%) and 329 cruciate sacrificing (69%) knees implanted. Patella resurfacing was performed on 89% (432) of the cases. Sixty-seven deaths occurred prior to 10 years follow-up. Patients were followed prospectively using validated clinical outcome scores (WOMAC, SF-12, Knee Society scores) and radiographs. Kaplan-Meier survival analysis was performed.

Results: All health-related outcomes were significantly improved from preoperative with a mean Knee Society Score and WOMAC at last follow-up of 162 and 69, respectively. To date, 16 revision procedures have been performed. Revisions for infection included six two-stage revisions and two cases of irrigation & debridement with polyethylene exchange. In addition, there were three re-operations for stiffness and one for patellar instability. To date, there have been only two revisions for aseptic loosening and/or osteolysis. Excluding revisions for infection, the Kaplan-Meier survivorship analysis of the total knee system was 98.9±0.5% at five years and 98.2±0.6% at 10 years.

Conclusion: The Genesis II total knee arthroplasty system, characterized by “built-in” femoral external rotation, improved trochlear design, a polished tibial base plate and ethylene-oxide sterilized polyethylene, has demonstrated excellent clinical & radiographic results and long-term survivorship (98% at 10 years) at our institution.


Maxwell McCabe Steven JM MacDonald Richard W McCalden Robert B Bourne Douglas D Naudie

Purpose: Total knee arthroplasty (TKA) is a proven intervention in the management of end-stage knee arthritis. However, the demands of younger, more active patients may result in increased rates of wear and aseptic loosening. The purpose of this study was to assess the long-term outcome of a large cohort of young patients, and to assess if the outcomes of cemented implants differed from non-cemented implants.

Method: Between 1984 and 2003, 350 TKAs were performed in 283 patients who were under 55 years old. Patients were followed a minimum of 5 years. Mean age at time of surgery was 49.0±5.5 years; 64% of patients were female. Primary knee pathologies included degenerative and post-traumatic arthritis (271), inflammatory arthritis (62), and others (17). Multiple implant designs were used; 296 knees were cemented and 54 were non-cemented. The Knee Society Clinical Rating Score (KSCRS) at latest follow-up was calculated. The Kaplan-Meier survivorship was calculated using an endpoint of revision total knee arthroplasty.

Results: Mean follow-up was 8.7±3.4 years. Seventeen knees were revised at a mean of 7.1±4.4 years after the index procedure. Fifteen patients (twenty-five knees) died. Fifty-one patients (sixty-two knees) were lost to follow-up. Sixty patients (sixty-seven knees) had incomplete KSCRS forms. Average function and knee domains of the KSCRS were 70.0±26.7 and 87.3±16.2 respectively. The Kaplan-Meier survival at five, ten, and fifteen years was 0.965±0.011, 0.941±0.015, and 0.933±0.017. The rate of revision was 5.9%. There was no statistically significantly difference observed between the outcomes of cemented and non-cemented implants, male and female patients, or inflammatory versus non-inflammatory arthritis.

Conclusion: This study demonstrates that total knee replacement in younger patients can demonstrate excellent survival rates free of revision. There does not appear to be an obvious survival advantage of cementless designs, or difference in outcomes based on sex of the patient or primary diagnosis of inflammatory or non-inflammatory arthritis.


Siva K Ariaretnam Robert B Wallace Robert B Bourne Steven JM MacDonald Richard W McCalden Douglas D Naudie Kory D Charron

Purpose: Approximately, 10% of two-stage TKA revisions for deep sepsis become re-infected. The purpose of this study was to determine the success in terms of sepsis eradication and factors associated with failure of repeat two-stage revision TKA.

Method: Between 1991 and 2006, 129 two-stage revision TKRs for deep sepsis were performed. Ten cases which became re-infected were identified. These unfortunate patients, representing 8% of all the two-stage TKA revisions performed during this time period, are the focus of this study. Their progress and treatment interventions were followed for the purposes of this study.

Results: Ten patients were identified with a two-stage revision TKA which became re-infected. Mean patient age was 72 with 40 % being female. Following recurrent sepsis all patients went on to require more than one further two-stage revision (mean 3.67 further revision surgeries). Infection was only successfully eradicated in 28.7% of cases, the remaining require chronic suppressive therapy or have ongoing active infection. Two patients went on to have an arthrodesis (both remain on suppressive anti-biotics) and one patient had trans-femoral amputation. Staph Aureus and Coagulase neg Staph accounted for 80% of primary infective organisms with only one primary infection with methicillin resistant staph aureus (MRSA). Cultures at subsequent revisions were the same organism in 67% cases. Additional organism cultured included Pseudomonas and Propionibacterium. These patients had an increased incidence of multiple medical co-morbidities including Type-2 Diabetes Mellitus and Rheumatoid Arthritis.

Conclusion: Patients with recurrent sepsis after a two-stage revision for infection in TKR all required multiple further surgeries. Eradication of infection was only achieved in 28.7% cases. Risk factors for recurrent sepsis include Rheumatoid Arthritis and Type-2 Diabetes Mellitus.


John M Froelich Wendy M Novicoff William M Mihalko Khaled J Saleh

Purpose: The purpose of this study was to examine the effects of baseline mental health on functional outcomes after primary knee arthroplasty by reviewing the data collected in a multi-center prospective observational cohort study. We hypothesized that those patients with lower baseline mental health status would demonstrate significantly worse outcomes vs. their counterparts with higher mental status following primary total knee arthroplasty.

Method: Data from a multi-center prospective cohort study of PS (posterior stabilizing implant) and CR (cruciate retaining implant) primary knee arthroplasty were compared to determine the relationship between baseline mental health status and functional outcomes post-surgery. Subjects were followed from the time of the index surgery to monitor outcomes and complications. Validated quality of life instruments, including SF-36, WOMAC, Knee Society Score, and an activity scale were used. The rates of improvement from 0 to 12 months were analyzed for this study.

Results: Baseline data was available for 436 subjects in the primary PS study and 493 subjects in the primary CR study. Patients improved significantly on all SF-36 and WOMAC components between baseline and 12 months post-surgery. Correlation and regression analysis between WOMAC and SF-36 showed that Global Health (GH), Mental Health (MH), and Mental Component Score (MCS) subscales on the SF-36 were significantly associated with positive post-operative changes in WOMAC scores.

Conclusion: This study examined the effects of baseline mental health on functional outcomes after primary knee arthroplasty and found that baseline mental health was a significant predictor of functional outcomes twelve months after surgery. This relationship between mental health and outcomes needs to be examined carefully to help surgeons better prepare their patients for surgery.


Bas A Masri Christopher R Gooding Nelson V Greidanus Donald S Garbuz

Purpose: Between 1 and 2% of knee arthroplasties are complicated by infection with its associated patient morbidity. Two stage revision remains the gold standard with the minimum interval considered acceptable between the two stages as 6 weeks, but in some cases can be considerably longer depending on the patients’ clinical response to the first stage and intravenous antibiotics. The interval between the 2 stages is to allow eradication of the causative organism, however, this can result in considerable morbidity for the patient. Patients often have a poor range of movement, instability and considerable discomfort during this time and as a result have poor mobility. Further complications can be encountered at the time of the 2nd stage with considerable scarring of the soft tissues, in part secondary to the lack of mobilisation. Traditionally, spacers which are non-articulating have been used, however, problems of instability, scarring and bone erosion have been reported in the literature. The Prostalac knee spacer constitutes an antibiotic loaded acrylic cement body with a metal on polyethylene surface and enables the patient to undergo rehabilitation in the interval between the 2 stages and may also help maintain soft tissue planes as a result. Previous published results with a mean follow up of 48 months suggest the spacer is just as successful at eradicating infection (91%) as other techniques. The aim of this study is to review 119 patients with a minimum follow up of 5 years.

Method: The Prostalac Knee spacer has 2 components, a femoral and a tibial. Each are made of antibiotic-loaded acrylic cement with a small articulation of metal on polyethylene. The spacers are made from moulds so that a component of a suitable size and thickness could be made. This was a retrospective review of 119 consecutive patients. The inclusion criteria included all patients who had undergone a 2 stage revision with the Prostalac Knee spacer who had more than 5 years of follow up. Patients were assessed using the WOMAC, SF-12, Oxford Knee Score and the Knee Society Score.

Results: Thirteen patients (10.9%) out of a total of 119 had recurrence of infection. This gives an overall rate of control of infection of 89%. Of the 46 patients who completed the outcome score questionnaires with more than 5 years follow up, the mean WOMAC score was 65.9, Oxford Knee score was 61, SF-12 (physical component) was 35.7, SF-12 (mental component) was 54.8.

Conclusion: Although the Prostalac components include polyethylene and metal, they do not seem to have a detrimental impact on the rate of control of infection since our results were similar to those previously reported with other best practice techniques. It is our impression that the Prostalac functional spacer allows earlier pain free mobilisation, allowing the potential for earlier hospital discharge. The savings obtained from earlier hospital discharge greatly outweighing the increased cost of the Prostalac functional spacer system.


Vaughan R Poutawera Jeffrey D Gollish Ahsan J Butt

Purpose: Total knee arthroplasty is one of the most successful modern surgical interventions with excellent clinical outcomes and implant survivorship. Nevertheless, with the increasing numbers of primary knee replacements being performed and increasing life expectancy, the need for revision arthroplasty continues to grow and is expected to grow considerably in to the future. Stemmed implants are commonly used in revision knee arthroplasty to provide adequate support for the joint interfaces. Controversy exists amongst surgeons as to the relative merits of cemented versus uncemented stems in revision knee arthroplasty. Cementing stemmed components in revision knee arthroplasty surgery is well established, and has well documented success rates. Though in widespread use, there is little data published regarding the technique of cementing short stubby tibial stems in revision TKA. We describe modes of failure in knee arthroplasty, our technique for revision, and early outcomes for this patient cohort.

Method: This was a retrospective analysis of a cohort of patients who have undergone revision knee arthroplasty. We evaluated the early clinical results looking for early failure in patients who have undergone revision knee arthroplasty using a short cemented tibial stem. All patients were operated on by a single surgeon in a single hospital. Baseline data was collected on all patients (age, gender, BMI, reason for revision, preoperative knee scores, details of surgery). Latest follow up clinical data, knee scores, and x-rays were evaluated to determine early patient outcomes and identify any implant or technical failure.

Results: Between 2003 and 2009, 77 of 241(32%) revision knee arthroplasty surgeries were performed using a short cemented tibial stem. This cohort of 77 patients included 49 females and 27 males. Eight knees (10%) were operated in two stages in the setting of deep infection. Average follow up for this group was 17 months (range 4 to 60 months). One patient developed a deep prosthetic infection requiring further revision surgery. No other patients to our knowledge have undergone further surgery and none have further surgery planned for mechanical failure or significant malalignment of the tibial prosthesis. No failure or early mechanical complication of using a short cemented tibial stem was identified clinically or radiographically.

Conclusion: We surmise the use of short cemented tibial stems in revision knee arthroplasty surgery is a safe and effective technique with potential advantages over longer cemented or uncemented stems. We have recorded satisfactory early outcomes, and continue to use this technique.


Rajiv Gandhi Holly Smith Kelly Lefaivre J Roderick Davey Nizar N Mahomed

Purpose: Minimally invasive surgery (MIS) knee replacement surgery has experienced a recent surge in popularity, driven by the patient concerns of a faster recovery time and a shorter, more cosmetic scar. However the evaluation of any new medical therapy must include a detailed evaluation of both efficacy and safety outcomes. The primary objective of our meta-analysis was to compare the incidence of complications between minimally invasive(MIS) and standard total knee replacement (TKR) approaches.

Method: We reviewed randomized controlled trials comparing minimally invasive TKR to standard TKR. After testing for publication bias and heterogeneity, the data were aggregated by random-effects modeling. Our primary outcome was the number of complications. Our secondary outcomes were alignment outliers, Knee Society Function Scores, and Knee Society Knee Scores.

Results: We had a total of 9 studies evaluating our primary outcome. Average follow up time ranged from 3 to 28 months. There was no significant publication bias in our study.

The combined odds ratios for complications for the MIS group and alignment outliers were 1.58 (95% CI: 1.01 to 2.47) p< 0.05 and 0.79 (95% CI: 0.34 to 1.82) p=0.58 respectively. The standard difference in means for Knee Society scores was no different between groups.

Conclusion: The results of this meta-analysis demonstrate a statistically significant increase in complication rates with MIS TKR when compared to standard TKR. There were no significant differences in postoperative alignment or KSS at 3 months between the two groups. MIS knee surgery should be approached with caution.


Daniel P Goel Darren S Drosdowech Joy Macdermid Kate Iosipchuk Paul Jarman Kenneth J Faber

Purpose: The reverse total shoulder arthroplasty (RTSA) has shown improvement in both pain control and function in recent studies. The purpose of this study was to prospectively analyze functional outcomes and strength in patients following the use of the Delta III prosthesis in a single center.

Method: Patients treated by one of two surgeons were prospectively evaluated following RTSA. An independent observer administered the Constant Score, SF-12, Shoulder Osteoarthritis (SOAQ), ASES, DASH questionnaires and patient satisfaction. Isometric strength testing was performed using the Powertrack II dynamometer. Follow-up for all patients was available up to 5 years following surgery.

Results: The Delta III RTSA was performed on 51 study patients (67% female, mean age 74 (SD=10)). Improvements following surgery were noted in Quality of life (SF-12 Physical Summary= 30 to 38); shoulder disability (SOAQ= 144 to 79; ASES 7 to 15; DASH= 61 to 46; Constant 21 to 56), Symptoms (SOAQ symptoms 40 to 22), Physical impairments as determined by strength (External rotation = 3 to 5 Nm, Abduction 4 to 10 Nm); and ROM (Flexion= 51 to 115°, abduction 45 to 106°); p< 0.05. All patients had follow up between 2–5 years. Satisfaction was high (86% extremely, 3% not at all).

Conclusion: Our data demonstrates significant improvements in quality of life, symptoms, patient satisfaction and disability with reduced and high at more than 2 years following RTSA. Novel to this study is improved objective evidence of strength in functional planes of motion. This is the first Canadian study to demonstrate such improvements in patients following RTSA.


Richard M Holtby Helen Razmjou Eran Maman

Purpose: The purposes of this study were to examine factors that influenced the decision to repair a SLAP Type II lesion and to examine the difference between patients with and without a SLAP repair.

Method: Prospectively collected data of patients who had a SLAP Type II lesion were reviewed. Patients who had a repair were compared with those who did not have a clinical indication for repair. Disability outcome measures collected pre and 2 years post-operatively were the American Shoulder and Elbow Surgeons (ASES) and the Constant-Murley scores (CMS). Paired and independent t-tests and logistic regression were performed.

Results: One hundred and six patients (83 males, 23 females), mean age=50 (SD=14, range 18–81), with a SLAP Type II lesion were identified. Eleven patients (10%) had isolated SLAP pathology for which they received a repair. The remaining 95 (90%) patients had concurrent pathologies related to rotator cuff, instability, osteoarthritis, and other pathologies. Repair of the SLAP lesion was felt to be clinically indicated in 43(45%) of patients with combined lesions. Factors that influenced the decision to repair the SLAP lesion were age, nature of the associated pathology, the presence of a large or massive full thickness rotator cuff tear, anterior instability, and a partial biceps tear greater than 50% that required a tenodesis. Significant improvement was observed in the ASES and CMS scores (p < 0.0001) whether or not a SLAP repair was performed.

Conclusion: This study indicates that age and presence of certain associated pathologies influence the need for SLAP Type II repair. A statistically significant improvement in strength and disability level is observed in patients with SLAP Type II lesions associated with concomitant pathology, despite not having the SLAP lesion repaired. The indications for SLAP Type II repair in the presence of other pathologies are discussed.


M Rouleau Jake Kidder Juan Pons de Villanueva Savvas Dynamidis Michael De Franco Gilles Walch

Purpose: The glenoid status is a crucial aspect of planning for shoulder replacements. This study revisits the classification proposed by Walch et al and discusses its value to orthopedic surgeons in terms of reproducibility and reliability.

Method: Three evaluators viewed one hundred-sixteen (116) shoulder CT-scans with primary glenohumeral arthritis and classified glenoid wear according to Walch classification two times. The validation study was done for three sets of data: Set I: the complete classification: A1, A2, B1, B2, C. Set II: regrouping with main categories: A,B,C. Set III: regrouping categories according to glenoid facet morphology; Normal concavity: A1, A2, B1; Biconcave glenoid: B2; Retroverted glenoid: C.

Results: Intra-observer Kappa values for Observer 1, 2, and 3 averaged 0.866 (0.899, 0.927, 0.773) for Set I; for Set II, the values averaged 0.915 (0.955, 0.975, 0.814); and for Set III, the values averaged 0.874 (0.897, 0.948, 0.777), all excellent values. Inter-observer reliability values for Set I averaged 0.621 (0.776, 0.512, 0.574), indicating good agreement; for Set II, the values averaged 0.759 (0.880, 0.713, 0.685), indicating excellent inter-observer agreement; and for Set III, the average was 0.642 (0.825, 0.519, 0.581), indicating good inter-observer agreement.

Conclusion: A clarification of the Walch et al classification of the osteoarthritic glenoid was necessary, especially with regards to the wordings of categories B2 and C. When used properly, it is a reliable and valuable tool for orthopedic surgeons of all levels of experience in the evaluation of the osteoarthritic glenohumeral joint.


Thomas R Turgeon Eric R Bohm Martin J Petrak Michael Sinaisky

Purpose: While it is generally accepted that the results of revision total knee replacement (TKR) are inferior to those of primary TKR, there is little published information documenting this. The purpose of this study is to compare patient-reported functional outcomes following primary and revision total knee arthroplasty patients using standardized, validated outcome metrics.

Method: Using data from an academic arthroplasty database, we undertook a review of health related quality of life (SF-12) and disease specific measures (WOMAC) of patients undergoing either primary or revision TKR. The sample included 39 patients who had undergone revision TKR for reasons other than infection, and 39 patients who had undergone primary TKR matched by gender, age, modified Charnley classification, and number of years of follow-up. Student’s t-test was used to compare both groups. Average length of follow up was 2 years.

Results: The mean age was 65 years. Sixty percent (67%) of the patients were female.

Despite being matched by age, gender and modified Charnley classification, there were significant differences in post-operative functional scores. The revision TKR group’s mean WOMAC score was 73 (SD 17), compared to the primary group’s mean score of 84 (SD 14), p=0.002. Similarly, the revision group’s mean SF-12 PCS score was 35 (SD 8) compared to the primary group’s superior score of 44 (SD 10), p< 0.0001. There was no differences detected in post-operative SF-12 mental component scores; 49 (SD 12) for the revision group compared to 53 (SD 10) for the primary group, p=0.11.

Conclusion: This study confirms the general clinical impression that the functional results of revision TKR are inferior to primary TKR, as measured by both the WOMAC and SF-12 tools.


Adrienne M Kelly Kelly Trask Ross K Leighton

Purpose: Proximal humeral fractures are a commonplace injury, especially in the elderly population. Management is not always straightforward, and is particularly challenging when bone quality is poor. In recent years, locking plates have become available for the internal fixation of many types of fractures, including those of the proximal humerus, and a growing trend in their use has been noted. This is a randomized biomechanical study to evaluate the mechanical stability in simulated osteoporotic bone of three fixation plates, two locking and one conventional, for unstable two-part proximal humeral fractures.

Method: Eighteen synthetic left humeri were plated with six bones in each of three groups: Synthes Cloverleaf Plate, Synthes Locked Compression Plate Proximal Humerus, and Smith and Nephew Periarticular Locking Plate for Proximal Humerus. Screw holes were overdrilled to simulate osteoporotic purchase. The distal humeral condyles were potted in autobody cement in polyvinylchloride tubes. An eight millimeter osteotomy gap was made at the base of the greater tuberosity to simulate an unstable two-part fracture. Cyclic axial compression testing was done in the vertical plane in 20 degrees of abduction to simulate physiologic loading. Measurements of plastic deformation of the construct were quantified by comparing RSA images taken before and after loading. Following cyclic axial compression testing, quasi-static torsion testing was done in the horizontal plane until construct failure. Failure was defined as the point where the linearity of a load-displacement curve is lost or where visible failure of the fixation occurs.

Results: No plates were loaded to failure. The locked plates were significantly stiffer in axial compression and torsion than the Cloverleaf plate. There was no difference between locked plates. The maximum total point motion seen on the RSA analysis was more than 4 times greater in the Cloverleaf group relative to either locked construct and no difference between the Synthes and Smith and Nephew locked plates was again seen. The majority of the motion in the Cloverleaf construct appeared to be in rotation about the anteroposterior axis (lateral rotation).

Conclusion: This study supports that locked plates, regardless of manufacturer, are stiffer in axial compression and torsion than Cloverleaf plates and result in less displacement in an unstable fracture pattern in an osteoporotic bone model.


Helen Razmjou Richard Holtby Suzanne Denis Terry Axelrod Robin R Richards

Purpose: The purpose of this study was to examine the measurement properties of four commonly used disability measures. We hypothesized that all measures would have a high (0.8 or > 0.8) internal consistency and ability to discriminate between men and women’s level of disability. A moderate convergent validity (0.5 to 1.00).

Method: This was a prospective longitudinal study of patients with advanced primary osteoarthritis of glenohumeral joint who underwent a Total Shoulder Arthroplasty (TSA). Four measures [Western Ontario Osteoarthritis Shoulder (WOOS) Index, the American Shoulder and Elbow Surgeon’s (ASES) assessment, Constant-Murley Score (CMS), and Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH)] were completed 2–3 weeks before surgery and at 6 months after surgery. The measurement properties were examined in:

internal consistency as a measure of reliability,

cross-sectional and longitudinal convergent validity,

known group validity, and

sensitivity to change at 6 months following surgery.

Analysis involved calculating Cronbach Coefficient Alpha to measure internal consistency. Convergent validity was examined by the Pearson correlation coefficient. Analysis of Variance examined the extent of known group validity. The Standardized Response Mean (SRM) was used to measure the relative sensitivity to change.

Results: Seventy patients (mean age: 65, range: 35–86, 44 females, 26 males) participated in the study. The Cronbach Coefficient Alpha was high at 0.91, 0.86, and 0.83 for WOOS, ASES, and QuickDASH respectively. Cross-sectional convergent validity was moderate with correlations varying from 0.54 to 0.79. Longitudinal convergent validity ranged from 0.58 to 0.88. All measures were able to discriminate between men and women at p< 0.05 with Cohen’s d of 1.07, 0.85, 0.82, and 0.55 for QuickDASH, CMS, WOOS, and ASES respectively. The SRM was 2.41, 2.17, 1.88, and 1.63 for WOOS, CMS, ASES and QuickDASH respectively.

Conclusion: All four disability measures were valid and reliable in candidates for TSA. The WOOS, a disease-specific outcome demonstrated a higher reliability and sensitivity to change than other measures. QuickDASH had a better ability to differentiate between men and women. Clinicians may not gain additional information by administrating multiple similar outcome measures. Researchers will decrease their chance of declaring a statistical significance by choosing one primary outcome measure.


Martin J Bouliane David M Sheps Holman Chan Robert M Lambert Robert Glasgow Kyle A Kemp

Purpose: The Instability Severity Index Score (ISIS) is a 6-item questionnaire that has been reported to predict failure of arthroscopic Bankart repair among patients treated for recurrent anterior glenohumeral instability. Two of the ISIS items pertain to radiographic features (presence of a Hill-Sachs lesion, loss of glenoid contour). These, however have yet to be validated. The goal of this study was to examine the inter – and intra-rater agreement and corresponding reliability of the radiographic aspects of the ISIS.

Method: Fifty-two plain, randomly selected, true antero-posterior radiographs in 45° gleno-humeral external rotation were evaluated by five assessors (three upper extremity orthopaedic surgeons, one senior orthopaedic resident and one musculoskeletal radiologist). Radiographs were retrieved for patients with documented recurrent shoulder instability requiring surgical stabilization and placed in a blinded Microsoft Powerpoint presentation for evaluation. Assessors were asked to determine the presence/absence of a Hill-Sachs lesion and if a loss of glenoid contour was present. Radiographs were evaluated in random order on two occasions, separated by a one-week time interval. Intra – and inter-rater reliability was assessed using percentage of agreement and kappa statistics.

Results: For session one, the number of Hill-Sachs lesions observed among raters ranged from 11 to 32. This resulted in inter-rater agreement ranging from 48% to 78% (k = 0.07 to 0.42), indicating poor to fair reliability. Cases with loss of glenoid contour ranged from seven to 14 with inter-rater agreement of 66% and 90% (k = 0.01 to 0.61), suggesting poor to moderate reliability. Session two led to modest increases in inter-rater agreement. The number of Hill-Sachs lesions observed ranged from four to 30 (agreement of 48% to 84%; k = 0.11 to 0.60) indicating fair to moderate reliability and the number of cases with loss of glenoid contour ranged from three to 14 (agreement of 66% to 94%; k = – 0.04 to 0.69), ranging from poor to moderate reliability. With respect to intra-rater reliability, agreement ranged from 71% to 94% (k = 0.41 to 0.86) for Hill-Sachs lesions, indicating fair to good reliability and 76% to 94% (k= 0.20 to 0.74) for loss of glenoid contour, ranging from fair to good reliability. Intra-rater agreement and corresponding kappa values were highest among the upper extremity surgeons and the musculoskeletal radiologist, particularly for loss of glenoid contour (85% to 94%; k = 0.56 to 0.74) suggesting there is moderate to good reliability in this measurement.

Conclusion: Our results indicate that the intra-rater reliability of the ISIS radiographic features was highest among upper extremity specialists and the musculoskeletal radiologist, suggesting that the ISIS may have utility in an experienced clinician’s individual practice. As the inter-rater reliability appears low, particularly for Hill-Sachs lesions, its wide-spread use across surgeons should be examined in further research.


Emilie Sandman Dominique M Rouleau G. Yves Laflamme Fanny Canet Georges S Athwal Benoit Benoit Yvan Petit

Purpose: The literature contains little information on an objective method of measuring radiocapitellar joint translations, as would be seen with joint instability. The purpose of this study was to develop and validate a measurement method that was simple and that could be easily reproducible in a clinical setting or intra-operatively to assess radiocapitellar joint translations.

Method: We performed a radiological study on a synthetic elbow specimen in order to quantify radial head translations as related to the capitellum: the Radio-capitellum ratio (RCR). Thirty (30) lateral elbow x-rays were taken in different magnitude of subluxation of the radial head. The subluxation was created randomly by manipulation. X-rays where taken by fluoroscopy to obtain a perfect lateral view of the distal humerus. First, the evaluators determined the long axis of the radius and the center of the capitellum. The displacement of the radial head (in mm) was obtained by measuring the distance of the line perpendicular to the long axis of the radius passing through the center of the capitellum. Then, in order to adjust for variation of magnification, a ratio of the displacement of the radial head about the diameter of the capitellum was done. The RC ratio would be of zero because the long axis of the radius always crosses the center of the capitellum in a perfectly aligned joint. A five mm translation of the radial head and a capitellum diameter of twenty (20) mm would give a RCR of 25% and would be positive if anterior and negative if posterior. The measurements were done two times at one week intervals by three independent evaluators to test inter-observer agreement and intra-observer consistency. The radiological incidences were randomly ordered to minimize observer recall bias. Intra/inter-observer reliability was calculated using Intra-Class Correlation (ICC) and paired T-tests.

Results: The mean translation in the trial group was of 6,06% (SD 70.7%) from – 167% to 125%. A result over 100% means that it is a complete dislocation ie – the axis of the radius is outside of the capitellum. Negative values signify posterior translation and positive values an anterior translation. Intra-observer reliability was excellent for the Radio-capitellum ratio (ICC 0.988 and 0.995) and inter-observer reliability was excellent (ICC 0.984 in average). Paired T-test results confirm a high intra-observer repeatability (p=0.97 and p=0.99) as well as a large inter-observer reproducibility (p=0.98 in average).

Conclusion: The proposed measurement of radial head translation about the capitellum (in percent): radio-capitellum ratio (RCR) has excellent inter – and intra-observer reliability when using our measurement method.


R Andrew Glennie Joshua W Giles Louis M Ferreira George S Athwal James Johnson Kenneth Faber

Purpose: Glenoid component loosening is a common reason for failed total shoulder arthroplasty. Multiple factors have been suggested as causes for component loosening including asymmetric loading of the glenoid prosthesis by the humeral head (rocking horse phenomenon). A novel technique was employed to measure in-vitro strain in the subchondral bone adjacent to a cemented all polyethylene pegged glenoid prosthesis. The purpose of the study was to develop and validate a testing protocol to investigate load transfer in the polyethylene glenoid implant and bone construct.

Method: Eight polyethylene components were implanted using standard cementing techniques in eight cadaveric specimens. Loading was performed with a pneumatic actuator capable of applying loads at various angles. A dynamic 10 N/s force was applied for a total of 15 seconds producing a maximum force of 150N at angles of 0, 10, 20, 30, 40 and 50o. Strain gauges were placed around the implant 1mm proximal to the bone-cement interface at the four quadrants. The humeral head was simulated with a custom steel ball with a non-conforming diameter in relation to the prosthesis that is typical in total shoulder arthroplasty.

Results: During pure compressive loading, tension was observed in the superior and inferior quadrants of the glenoid. Superior and inferior loading caused increasing same side (ipsilateral) tension, occurring from 0 to 30o and 0 to 20o, respectively. Compression was recorded superiorly when loading was applied at 40o and 50o in the superior direction while contralateral tension was recorded in the inferior gauges. Strain measurements were less consistent in the anterior and posterior glenoid quadrants and varied between tension and compression.

Conclusion: Tension measurements in the ipsilateral direction at lower angles were unexpected. This observation differs from the previous assumption that applied loads at relatively perpendicular angles to the implant should dissipate as compression. Tension at the bone cement interface is unfavorable. The identification of tension in some quadrants of the implant in this study, therefore, may have revealed a mechanism of implant loosening. Our data support the previously described rocking horse phenomena and also illustrate a new umbrella type effect of polyethylene flexure, which causes the periphery of the glenoid implant to flex upwards superiorly and inferiorly. These findings have the potential to influence future designs of total shoulder arthroplasty perhaps leading to increased implant survival.


Justin M LeBlanc Carol Hutchison Manar Din Samad Aron Su Antoine Widmer Yaoping Hu Tyrone Donnon

Purpose: Surgical trainees develop psychomotor skills using various techniques, with simulators providing safe practicing environments. There has been no development of virtual simulators with haptics (force feedback) that allow residents to practice the open surgical fixation of common orthopedic fractures. The main purpose of this study was to assess if residents performed similarly on a newly developed virtual simulator as on a Sawbones simulator using a modified checklist and global rating scale. Secondary purposes were to assess the reliability and validity of these procedural measurement tools.

Method: A stratified randomized within-subjects study was performed with 22 surgical trainee volunteers. They were randomized to first perform surgical fixation of the ulna using either the virtual or Sawbones simulator, and then performed the same procedure on the other simulator. Evaluators completed a task-specific checklist, global rating scale (GRS), total error score and time to completion for each participant on both simulators.

Results: The participants achieved significantly better scores on the virtual simulator compared to the Sawbones simulator (p0.8), except in time to completion. When combined, the checklist and GRS maintained high levels of internal consistency (Cronbach’s a > 0.80) and inter-rater reliability (intraclass coefficient > 0.90) for both simulators. A Pearson’s product moment correlation was used to demonstrate criterion validity of the measurement tools. They were all significantly correlated to each other within simulators (p0.9), while the virtual simulator achieved construct validity for the GRS and total error score (p1.1).

Conclusion: The modified procedural measurement tools demonstrate reliability and validity and the virtual simulator shows evidence of construct validity. These tools were used to evaluate participants, demonstrating the achievement of better scores on the virtual simulator compared to the Sawbones simulator. The only concern at this time is that the procedural measurement tool scores do not correlate between simulators. The newly developed virtual ulna surgical fixation simulator with haptics shows promise for helping surgical trainees learn and practice basic skills, but requires further modifications before it can attain the same standards as the current gold standard simulators.


Jesse A Shantz Jeffrey Leiter Sheila McRae Peter B MacDonald

Purpose: The development of confidence in the operating room is a major goal of surgical training. Confidence in surgery involves trusting information, intuition and experience. Confidence can also be detrimental when it impedes the ability to self-assess skills and decision-making. The measurement of confidence is difficult owing to the sequential acquisition of information and experience. The following study examines the trends in self-reported confidence in residents participating in cadaveric arthroscopic courses.

Method: In 2007 and 2008 residents participating in annual arthroscopic courses at the returned pre-course and post-course questionnaires recording previous arthroscopic exposure. Participants had access to fresh-frozen cadaver specimens and arthroscopic instruments for five hours after didactic lectures. Each participant rated perceived confidence and skill on a five-point Likert scale before and after the course. Mean confidence was compared using a student’s t-test. Data were further analysed using linear regression of pre – and post-course Likert scores.

Results: Residents showed a significant increase in self-perceived confidence in the performance of meniscal repair, anterior cruciate ligament reconstruction and labral repair and subacromial decompression directly after an arthroscopy course (p< 0.01). Regression analysis yielded a y-intercept not significantly different from zero prior to the course with a significant increase in the intercept after the course. There was no significant difference in the relationship of increasing arthroscopic experience to training noted as a result of the course.

Conclusion: Novice residents appeared to gain more self-reported confidence than experienced residents following an arthroscopic skills course. Future courses should consider the separation of novice and experienced residents to focus on improving the self-perceived confidence of experienced residents while exposing novice residents to the complexities of arthroscopic techniques. More research is needed to increase the understanding of the effects of confidence on trainees at various stages of training.


Ryan T Bicknell Alex Bertelsen Frederick Matsen

Purpose: The objectives of this study were:

to determine if the deltoid, conjoint tendon and long head of the triceps provide sufficient soft tissue tension to stabilize a RTSA, and;

to determine the influence of loading direction, arm rotation, shoulder position and polyethylene thickness on stability of a RTSA.

The hypotheses were:

that the deltoid, conjoint tendon and long head of the triceps provide sufficient soft tissue tension to stabilize a RTSA, and;

that arm rotation, shoulder position and loading direction would affect stability and increased polyethylene thickness would be associated with increased stability.

Method: Six cadaveric shoulders had all capsule, rotator cuff, and scapulohumeral muscles removed, leaving only the deltoid, conjoint tendon (i.e. coracobrachialis and short head of biceps) and long head of triceps. A RTSA was then performed. A displacing force was then applied perpendicular to the centerline of the humeral socket and this load was increased until dislocation occurred. The load required to cause a dislocation was recorded for superior, inferior, anterior and posterior load directions. This was repeated to measure the effect of humeral component rotation (neutral, 20 degrees retroversion, 20 degrees anteversion), arm position (0 degrees abduction, 60 degrees flexion, 60 degrees abduction and 60 degrees extension) and polyethylene thickness (3, 6 or 9 mm). Statistical analysis used an ANOVA with Tukey post-hoc tests for multiple comparisons (p< 0.05).

Results: The deltoid, conjoint tendon and long head of the triceps provide sufficient soft tissue tension to stabilize a RTSA. The required dislocation force was increased for an inferior direction of load application (p0.05). The required dislocation force was least in an arm position of 60 degrees abduction, followed by 60 degrees extension, with no difference between 0 degrees abduction and 60 degrees flexion (p0.05).

Conclusion: The deltoid, conjoint tendon and long head of the triceps provide sufficient soft tissue tension to stabilize a RTSA. Stability of a RTSA was greatest for an inferior directed force and an arm position of 0 degrees abduction or 60 degrees flexion. There was no influence of arm rotation or polyethylene thickness on stability of a RTSA. This study indicates that stability of a RTSA can still be achieved despite significant soft tissue loss, as long as key soft tissue structures remain intact. As well, certain loading directions and arm positions lead to an increased risk of instability. However, further in vivo studies are required.


Daniel P Goel George S Athwal Joy Macdermid

Purpose: The success of humeral head replacement following fracture is reliant on several factors, one of which is version. The correct humeral version (HV) is highly variable, and is patient and side dependent. In the setting of fracture, there is no intra-operative landmark to guide the surgeon as to the anatomic version. This study has examined computed tomography (CT) of the shoulder and compared the HV to the metaphyseal version (MV) to evaluate reliability in predicting the anatomic version.

Method: A retrospective review of 50 shoulder CT scans was carried out. Patients were excluded if the anatomy prevented HV or MV evaluation. The HV and MV was measured by 2 independent evaluators. Inter and intra-rater reliability was performed.

Results: There were 27 right and 23 left shoulder CT’s reviewed. The mean age of patients was 45.3 (range 13–85). The difference between the MV and HV was approximately 2.8 (95% CI 0.63–5.1). Inter and intra-rater reliability was 0.966 and 0.984, respectively.

Conclusion: Determining the version of the humeral head in the setting of fracture is difficult and highly inaccurate. The biceps groove has been previously cited as a landmark for arthroplasty position, however, given the anatomic variability, version may be miscalculated. We have demonstrated the medial calcar of the proximal humerus is within 3 degrees of the actual humeral head version. This CT guided approach is novel, reproducible and demonstrates excellent reliability. It is both accurate and consistent and may be successfully utilized in the setting where normal anatomic landmarks are absent, such as fracture.


Emil H Schemitsch Mohit Bhandari

Purpose: Intimate partner violence (IPV), also known as domestic violence, is a pattern of coercive behaviors that include repeated physical, sexual and emotional abuse. Musculoskeletal injuries are common manifestations of IPV. We aimed to determine the proportion of women presenting to orthopaedic fracture clinics for treatment of orthopaedic injuries that have experienced IPV defined as physical, sexual, or emotional abuse within the past 12 months.

Method: We completed a cross-sectional study of 282 injured women attending two Level I trauma centres in Canada. Female patients presenting to the orthopaedic fracture clinics completed two validated self-reported written questionnaires (Woman Abuse Screening Tool (WAST) and the Partner Violence Screen (PVS)) to determine the prevalence of IPV. The questionnaire also contained questions that pertain to the participant’s demographic, fracture characteristics, and experiences with health care utilization.

Results: The overall prevalence of IPV (emotional, physical, and sexual abuse) within the last 12 months was 32% (95% Confidence Interval 26.4% to 37.2%) (89 of 282 women). One in 12 injured women disclosed a history of physical abuse (24/282, 8.5%) in the past year. Seven women (2.5%) indicated the cause for their current visit was directly related to physical abuse, of which five were fractures. We did not identify any significant trends in ethnicity, socioeconomic status, or injury patterns as markers of domestic abuse. Of 24 women with physical injuries, only four had been asked about IPV by a physician, none of whom were their treating orthopaedic surgeons.

Conclusion: Our study confirms a high prevalence of IPV among female patients with injuries attending orthopaedic surgical clinics in Ontario. Similar to previous research our study found that women of all ages, ethnicities, social economic status, and injury patterns may experience IPV. Surgeons should consider screening all injured women for domestic violence in their clinics.


Markku T Nousiainen Patrick Zingg Daniel Omoto Heather Carnahan Yoram Weil Hans Kreder David L Helfet

Purpose: This study attempted to determine if the form of feedback provided by a computer-based navigation technique improves the learning of the placement of cannulated screws across a femoral neck fracture in the surgical trainee.

Method: A prospective, randomized, appropriately powered, and controlled study involving 39 surgical trainees (first-year residents and fourth-year medical students) with no prior experience in surgically managing femoral neck fractures were used in the study. After a training session, participants underwent a pretest by performing the surgical task on a simulated hip fracture using fluoroscopic guidance. Immediately after, 20 participants were randomized into undergoing a training session using a conventional fluoroscopy-guided technique while the other participants were randomized into undergoing a training session using a computer-based navigation technique. Immediate post-tests and retention tests (4 weeks later) were performed. A transfer test was used to assess the impact of the type of training on surgical performance – after performing the retention test, each group repeated the task but used the other technique to guide them (i.e. those trained with fluors-copy used computer navigation and vice versa).

Results: Screw placement was equal and to the level of an expert surgeon with either training technique during the post-, retention, and transfer tests. Participants that were trained with computer navigation took fewer attempts to position hardware and used less fluoroscopy time than those that trained with fluoroscopy. When participants that trained with computer navigation reverted to conventional fluoroscopic technique at the transfer test, more fluoroscopy time and dosage was used. Participants that trained with fluoroscopy used less fluoroscopy time and took fewer attempts to position hardware when they subsequently used computer navigation to perform the task during the transfer test.

Conclusion: Computer navigation does not harm the learning of surgical novices in this basic orthopaedic surgical skill. Training with computer navigation minimizes radiation exposure and decreases the number of attempts to perform the task. No compromise in learning occurs if a surgical novice trains with one type of technology and transfers to using the other.


Veronica M Wadey Parvati Dev Richard Buckley Douglas Hedden

Purpose: The RCPSC Orthopaedic Specialty Committee for Residency Training and the Examination Committee for Orthopaedic Surgery requested that work be completed to assist with identifying competencies that should be included in a core curriculum for graduating orthopaedic surgery residents in Canada. The purpose of this study was to determine competencies to be of greatest importance by orthopaedic surgeons whose primary affiliation was non-university, for the purpose of developing a core curriculum in orthopaedic surgery for graduating residents within Canada.

Method: A 281-item list of competencies was developed consisting of three sections: a previously validated curriculum for musculoskeletal health, Orthopaedic Specialty objectives of the Royal College of Physicians and Surgeons of Canada, curricula representing orthopaedic programs from accredited academic orthopaedic programs within Canada and, a comprehensive procedure list. Competencies were compared to existing curricula within Canada. A content review was completed and a modified questionnaire was developed. A stratified, randomized selection of, non – university, orthopaedic surgeons rated each individual item on an integer scale 1 to 4 of increasing level of importance. Summary statistics across all respondents were given. Average mean scores and standard deviations were computed. Secondary analyses were computed in general, paediatrics, trauma and adult reconstruction.

Results: 131/156 (84 %) of orthopaedic surgeons participated. 240/281 competencies (85.4%) were rated average scores of at least 3.0 suggesting probably important or important to demonstrate competency by completion of training. 41/281 items (15.6%) were given average scores between 2.0 and 2.93 thus suggesting not important.

Conclusion: This study identified competencies necessary for a Core Curriculum for Orthopaedic Surgery. Complex procedures in various categories and content considered less essential for orthopaedic surgeons were rated to be less important. How curriculum is ultimately structured, delivered and implemented needs to be studied. We know that learning activities are “driven” by the evaluation of competencies. Is competency-based education on the horizon or should we be focused on assessing competencies within the current method of curriculum delivery?


Markian A Pahuta Emil H Schemitsch David Backstein Steven Papp Wade Gofton

Purpose: Preoperative planning forces the surgeon to understand the “fracture personality” and devise an operative plan. In our experience, trainees have difficulty in preparing for complex acetabular cases; these fractures are among the most difficult fractures to conceptualize and teach. As a result, these fractures are poorly understood as demonstrated by low interobserver agreement between trainees in the classification of acetabular fractures. We sought to determine whether the use of visou-haptic technology would help trainees to appreciate the “personality” of an Associated-Both-Column (ABC)fracture more accurately than trainees taught by conventional instruction.

Method: Thirty senior medical students and PGY1 residents, were randomized into two groups. The control group studied an ABC fracture with the aid of a textbook excerpt and a 3D CT reconstruction of the fracture. The intervention group was given the same instructional materials, and a visuo-haptic CT model of the fracture. All other learning variables, including time on task were standardized. Participants were evaluated on their accuracy in drawing the fracture lines on a model pelvis.

Results: There was no significant difference in gender, visuo-spatial ability, and training level between groups. The participants taught with the visuo-haptic model recalled an additional 26% anatomic relationships (p< 0.01) compared with the control group.

Conclusion: These findings suggest that in addition to the benefits observed in the learning of motor skills, visuo-haptic input may improve the understanding of spatial relationships. This technology may be a useful adjunct for teaching anatomy, as well as preoperative planning.


Harsha Malempati Veronica Wadey David Backstein Hans Kreder Scott Paquette Eric Massicotte Albert Yee

Purpose: To evaluate fellowship trainee and supervisor perceptions on the relative importance of core cognitive and procedural competencies in spine subspecialty fellowship training.

Method: A questionnaire was designed through synthesis and amalgamation of two previous surveys designed by other authors. This questionnaire was reviewed for content by spine surgery experts (Canadian Spine Society Education Committee). The questionnaire was administered (online and paper) to fellow trainees and supervisors across Canada and data was collected over a 3-month period. It consisted of 40 MCQ items grouped into 13 broad cognitive skills categories, as well as 29 technical/procedural items. Data was analyzed using qualitative and descriptive statistics (e.g. average mean scores, standard deviations, t-tests).

Results: The response rate was 91%, with 15 of 17 fellow trainees and 47 of 51 supervisors completing the survey. Twelve of the 13 core cognitive skill categories were rated as being important to acquire by the end of fellowship. Trainees were not comfortable performing, and requested additional training in 8 of 29 spine surgery technical skill items. Specifically, additional training was believed to be required for intradural procedures (e.g. syringomyelia, intradural neoplasms) and other less common, technically demanding, procedures (e.g. transoral odontoidectomy, anterior thoracic discectomy). Significant differences (p< 0.05) existed in perceptions of importance for specific cognitive and technical skills based on previous residency training (orthopaedic or neurosurgical). No such differences were found when comparing responses of the fellow trainees and their supervisors.

Conclusion: This study demonstrates that fellowship trainees and supervisors have similar perceptions on the relative importance of specific core cognitive and procedural competencies required in achieving successful spine fellowship training. Furthermore, background specialty training (orthopaedic or neurosurgical) influences the perceptions of both fellow trainees and supervisors regarding the importance of specific cognitive and technical skills deemed necessary for successful training.


Ali Zahrai Jaskarndip Chahal Dan Stojimirovic Albert Yee Emil H Schemitsch William Kraemer

Purpose: Given recent evolving guidelines regarding maximum allowable work hours and emphasis on resident quality of life, novel strategies are required for implementing call schedules. The night float system has been used by some institutions as a strategy to decrease the burden of call on resident quality of life in level one trauma centres. The purpose of this study was to determine whether there are differences in quality of life, work-related stressors, and educational experience between orthopaedic surgery residents in the night float and standard call systems at two level one trauma centres.

Method: This was a prospective cohort study at two level one trauma hospitals comprised of a standard call (1 in 4) group and a night float (5pm-7am, Sunday to Friday) group for each hospital, respectively. Residents completed the Short Form 36 (SF-36) general quality-of-life questionnaire, as well as, questionnaires on stress level and educational experience before the rotation (baseline), at two, four and subsequently at six months. An analysis of covariance (ANCOVA) approach was used to compare between-group differences using the baseline scores as covariates. Wilcoxon Signed-Rank tests (non-parametric) were used to determine if the residents’ SF-36 scores were different from the age and sex matched Canadian norms. Predictors of resident quality of life were analyzed using multivariable mixed models.

Results: Seven residents were in the standard call group and nine in the night float group for a total of 16 residents (all males, mean age=35.1 yrs). Controlling for between-group differences at baseline, residents on the night float rotation had significantly lower role physical (RP), bodily pain (BP), social function (SF) subscale scores (p< 0.05).

Conclusion: Our study suggests that the residents in the standard call group had better health related quality of life in comparison with the night float group. No differences existed in subjective educational benefits and stress level between the groups. The study findings may be limited due to the small sample size. However, this sample size is substantial given the size of most orthopaedic residency programs in North America.


M Hoang-Kim Mohit Bhandari Dorcas E Beaton Emil H Schemitsch

Purpose: Today, numerous functional outcome tools exist to assess the patient’s ability to carry out basic and instrumental activities of daily living. Furthermore, the increase in range of mobility measures reflect differences in rating scales, scores, administration and scoring options which make outcome results difficult to assess across trials. Because of the lack of consensus among investigators, we wanted to identify the citation patterns of the functional outcomes tools used by investigators in hip fracture RCTs. We believed that the lack of proper citation is an underlying factor in the diverse usage of outcome tools.

Method: We extracted the citations of disability tools from 59 Level 1 hip fracture RCTs. Disability was defined using the WHO classification (ICF). We excluded measures assessing body structure. The text and reference lists of the identified articles were screened in order to compile relevant literature on the instrument used in the RCT. Disability tools which were cited in the references were also compared to original development articles.

Results: Overall 68 different instruments were identified that measured disability in the hip fracture literature. According to ICF, 47 tools measured body function alone, 13 tools evaluated activity limitations and participation restriction and 8 were composite scoring systems. We found that 34.2% of the trials did not provide any citations to the tools assessing body function. In trials measuring activity and participation, 23.2% provided instrument citations. In trials using composite scoring systems, 19.4% of the trials provided instrument citations. All of the instrument citations when provided by the investigators were found to correspond to original development articles or trials.

Conclusion: The appropriate choice of a functional outcome instrument is fundamental in order to ensure that the results that are obtained reflect the patient. However, if citations of the indices and scales themselves are lacking, trial methodology and results could be informative but not replicated. In the future, we recommend that rigor in quality reporting include proper instrument citations.


Christopher S Bailey Khalid Alsaleh Derek Ho Patricia Rosas-Arellano Stewart I Bailey Kevin R Gurr

Purpose: Magnetic resonance imaging (MRI) and Computerized tomography (CT) are commonly used for the diagnosis and assessment of lumbar spinal stenosis. The available literature has not identified which modality is superior. We compared the reliability and accuracy of CT and MRI in the assessment of lumbar spinal stenosis.

Method: We performed a prospective review of CT and MRI scans of 54 patients referred for surgical consultation. One orthopaedic spine fellow and one neuro-radiologist reviewed the CTs and MRIs. A qualitative and quantitative analysis was performed. Intra-observer and inter-observer reliability was determined using Kappa coefficient. The patient’s official reports were correlated with analysis performed by the two reviewers. Owsestry and SF-36 data was correlated with the qualitative and qualitative assessment of stenosis on CT, MRI using the Pearson’s R coefficient.

Results: MRI – substantial inter-observer agreement was achieved between surgeon and neuro-radiologist as well as between surgeon and reporting radiologist (κ= 0.74 and κ=0.64 respectively). Moderate agreement was found between neuro-radiologist and reporting radiologist (κ=0.57). Almost perfect intra-observer reliability for MRI was achieved by the two expert reviewers (κ=0.91 for surgeon and κ=0.92 for neuro-radiologist). CT – moderate inter-observer agreement (κ=0.58) was found between surgeon and neuro-radiologist. Fair agreement was found between neuro-radiologist and reporting radiologist and between surgeon and reporting radiologist (κ=0.30 and 0.32 respectively). Substantial intra-observer agreement was found for the surgeon (κ=0.77) while the neuro-radiologist achieved almost perfect agreement (κ=0.96).

Conclusion: This study directly demonstrates that MRI is likely a more reliable tool than CT, but neither correlates with functional status.


John M Froelich Joseph C Milbrandt D Gordon Allan

Purpose: Orthopaedic residency training requires intellectual and motor skill development. In this study we aim to develop a model to evaluate junior resident proficiency and efficiency versus senior residents in the placement of a center-center guidewire during fixation of an intertrochanteric proximal femur fracture utilizing a computer-based haptic simulator. We hypothesize the junior residents will utilize more fluoroscopy and require more time to complete the task.

Method: Post-graduate year residents (PGY) 3–5s, labeled Group II, placed a single central guide pin into a femoral head utilizing a surgical simulator four times. PGY 1–2s, labeled Group I, completed the same task six times. The residents were then evaluated based on final tip-apex distance (TAD), fluoroscopy time, time to complete the task, total number of distinct attempts at pin placement for each femur construct as well as final three-dimensional location of the pin from the isometric center of the femoral head. This project was approved by the institutional IRB.

Conclusion: In this study we displayed that based on our simulator model there was no statistical difference between Group I and II in time to completion, final placement on AP view, and tip-apex distance. There was a statistically significant difference in the anterior/posterior placement of the wire between the two groups, fluoroscopy time, and number of attempts per trial. Our findings suggest a computer based surgical simulator can identify measurable differences in surgical proficiency between junior and senior orthopaedic residents.


Christina Goldstein Stephen Petis Marcin Kowalczuk Brian Drew Brad Petrisor Mohit Bhandari

Purpose: A lack of consensus regarding the radiologic criteria to diagnose spinal non-union limits inferences from clinical research. This systematic review aimed to examine the spectrum of radiologic investigations used to assess lumbar spinal fusion and the definitions of successful spine union used in the spine literature.

Method: We comprehensively searched three electronic databases from 1950 to 2009 (MEDLINE, Embase and the Cochrane Central Register of Controlled Trials) for clinical studies involving posterolateral fusion of the lumbar spine. English-language studies including adult patients and reporting a definition of successful fusion were included. Studies examining the reliability and validity of radiologic investigations were also identified. Key measures included

radiologic investigations,

definition of successful lumbar fusion and

reliability, sensitivity and specificity of the investigations used to assess the spinal fusion.

Results: Among 1165 potentially eligible studies, 91 met our inclusion criteria. Of the studies 78% (n = 71) used plain radiographs to diagnose non-union, 4% (n = 4) used CT scans and 18% (n = 16) used both. Fifty-one studies used both static (xray or CT) and dynamic (flexion-extension xray) images, 35 used only static images and five used only dynamic radiographs. In total, we identified fifty-two different radiographic definitions of successful fusion. More than half of the studies (n = 50, 55%) failed to provide a reference for the definition used. The most common definition of fusion (7 studies) used static radiographs and defined fusion as continuous intertransverse bony bridging with this quality of fusion at all intended levels. Seven studies evaluated reliability of xray criteria but no studies provided complete validation of the definitions. Only 3 studies provided some validation and reliability estimates of thin-slice CT scanning in diagnosing spinal non-union. Significant variability in reliability, sensitivity and specificity exists for all radiologic investigations in the diagnosis of spinal non-union.

Conclusion: The radiologic investigations and definitions of successful posterolateral fusion used in the spine literature vary substantially. Choice of radiologic criteria should be based upon reliability and validity testing. Studies using fusion criteria that have not been shown to be reliable or valid should be interpreted with caution.


John Street Brian Lenehan Charles Fisher

Purpose: A systematic review of Health Related Quality of Life Outcomes(HRQOL) in metastatic disease of the spine and content validation of a new Spine Oncology Study Group Outcomes Questionnaire(SOSGOQ). To identify HRQOL questionnaires previously reported for spinal metastases and to validate the content of the new SOSGOQ based on the International Classification of Function and disability(ICF).

Method: A systematic review identified 141 studies. Reported outcome tools were enumerated. The most commonly utilized (ESAS, Karnofsky Scale and ODI) and the SOSGOQ were linked to the ICF. Descriptive statistics examined the frequency and specificity of the ICF linkage. Linkage reliability was evaluated by inter-investigator percentage agreement.

Results: The SOSGOQ contains 56 concepts, with all 4 domains of the ICF represented. 4 concepts could not be linked. There was 100% inter-observer agreement(IOA) for total number of concepts and for those ‘not covered’. 100% of concepts had ‘First and Second’ level linkage. 100% IOA exists at both ‘Component’ and “First Level’ linkage. There was 96.1% IOA at ‘Second’ Level. 33 concepts linked to Third Level with 96.9% IOA. 10 concepts linked at the Fourth Level with 100% IOA.

Conclusion: The SOSGOQ includes all domains relevant for measurement of function and disability and it’s content validity is confirmed by linkage with the ICF. This new questionnaire has superior content capacity to measure disease burden of patients with metastatic disease of the spine than any instruments previously identified in the literature.


Emily R Dodwell Brian Kwon Barbara Hughes David Koo Andrea Townson Allan Aludino Richard Simons Charles Fisher Marcel Dvorak Vanessa Noonan

Purpose: Multiple studies have described the general injuries associated with mountain biking. However, no detailed assessment of mountain biking associated spinal column fractures and spinal cord injuries (SCI) has previously been reported. The purpose of this study is to describe the patient demographics, injuries, mechanisms, treatments, outcomes and resource requirements associated with spine injuries sustained while mountain biking.

Method: Patients who were injured while mountain biking, and presented to a provincial spine referral centre between 1995 and 2007 inclusive, with SCI and/ or spine fracture were included. A chart review was performed to obtain demographic data, and details of the injury, treatment, outcome and resource requirements.

Results: 102 men and 5 women were identified for inclusion. The mean age at injury was 32.7 years 95%CI[30.6,35.0]. 79 patients (73.8%) sustained cervical injuries, while the remainder sustained thoracic or lumbar injuries. 43 patients (40.2%) sustained a SCI. Of those with cord injuries, 18(41.9%) were ASIA A, 5(11.6%) were ASIA B, 10(23.3%) ASIA C, and 10(23.3%) ASIA D. 67 patients (62.6%) required surgical treatment. The mean length of stay in an acute hospital bed was 16.9 days 95%CI[13.1,30.0]. 33 patients (30.8%) required ICU care, and 31 patients (29.0%) required inpatient rehabilitation. Of the 43 patients (39.6%) who presented with SCI, 14(32.5%) improved by one ASIA category, and 1 (2.0%) improved by two ASIA categories. Two patients remained ventilator-dependent at discharge.

Conclusion: Spine fractures and SCI due to mountain biking accidents typically affect young, male, recreational riders. The medical, personal, and societal costs of these injuries are high. Injury prevention should remain a primary goal, and further research is necessary to explore the utility of educational programs, and the impact of helmets and other protective gear on spine injuries sustained while mountain biking.


Marie-Lyne Nault Stefan Parent Marjolaine Roy-Beaudry Jacques A de Guise Hubert Labelle

Purpose: Prediction of progression is actually impossible in adolescent idiopathic scoliosis (AIS). Potential risk factor to consider at first visit might be morphologic parameters of the spine. The objective of this study was to compare 3D morphologic parameters of the spine in a non evolutive an in an evolutive group of AIS.

Method: A retrospective cohort study was done. Two groups were recruited with sample size based on a difference of 5 degrees for rotation parameters. First group were all surgical patients (n=19) and second group non evolutive patient (n=18). Inclusion criteria were

Risser sign of 0 or 1

Cobb angle between 11 and 40 degrees

AP and lateral radiograph available.

Exclusion criteria were

limb length discrepancy

syndromic or congenital scoliosis.

All spines were reconstructed in 3D with AP and lateral radiographs of the first visit and measurements were performed on the reconstruction. There were 4 categories of measurements done: Cobb angle, wedging, rotation, slenderness. Student t test were performed.

Results: There was no statistical difference between the two groups for Cobb angle in maximal plane, for lordosis and kyphosis. Differences were found for wedging of the apical disk in 3D plane (S=5,4° vs NE= 0,7° with p=0,04). For coronal orientation of the apex (S=7,8° vs NE=0,1° with p=0,01). For axial orientation of inferior junctional vertebrae (S=1,9° vs 0,1° with p=0,007). For torsion (S=−4,1° vs NE= – 1,2° with p=0,03). For ratio between height and width of T6 (S=51% vs NE=53,6% with p=0,04).

Conclusion: This study give for the first time some 3D morphologic parameters that could be use in the prediction of AIS. Some limitations exist such as the small sample size and the low level of significance. In the future those parameters will be used in the development of a prediction model base on those keys parameters that will confirm the actual findings.


Christina Goldstein Brad Petrisor Brian Drew Mohit Bhandari

Purpose: A significant proportion of spine fusion operations may result in a non-union. Electromagnetic stimulation is a non-invasive method used to promote spine fusion although the efficacy of its use in this regard remains uncertain. The purpose of this systematic review and meta-analysis is to evaluate the effect of electromagnetic stimulation on spine fusion.

Method: Five electronic databases (MEDLINE, Embase, CINAHL, PubMed and the Cochrane Central Register of Controlled Trials) were searched from database inception to July 2009 for randomized controlled trials of electrical stimulation and spinal fusion. In addition, we performed a hand search of four relevant journals from January 2000 to July 2009, the on-line proceedings of the North American Spine Society Annual Meeting from 2002 to 2008 and bibliographies of eligible trials. Trials randomizing adult patients undergoing any type of spine fusion to active treatment with direct current, capacitance coupled or pulsed electromagnetic field stimulation or placebo and reporting on fusion rates were included. Two independent reviewers extracted data regarding clinical outcomes, stimulation device, treatment regimen and methodologic quality.

Results: Of 1650 studies identified seven met the inclusion criteria. Electromagnetic stimulation in lumbar spine fusion was evaluated in five studies and two addressed cervical spine fusions. The use of electromagnetic stimulation in lumbar spine fusion resulted in a significant decrease in the risk of non-union (relative risk 0.60, 95% confidence interval 0.38 to 0.93, p = 0.02, I2 = 57%). The observed reduction in risk of nonunion with electromagnetic stimulation was not affected by smoking or the number of levels fused. Due to limited and conflicting trials, similar effects were not observed in the two studies evaluating cervical spine fusion rates (relative risk 0.85, 95% confidence interval 0.29 to 2.53, p = 0.77, I2 = 56%).

Conclusion: Pooled analysis shows a 40% reduction in the risk of non-union of lumbar spine fusions with the use of electromagnetic stimulation although a similar effect was not observed for fusions of the cervical spine. However, due to study heterogeneity the current indications for the use of electrical stimulation in spine fusion remain somewhat unclear.