Purpose: Osteochondritis dissecans (OCD) of the capitellum most commonly affects adolescent pitchers and gymnasts, and presents with pain and mechanical symptoms. Fragment excision is the most commonly employed surgical treatment; however, patients with larger lesions have been reported to have poorer outcomes. It’s not clear whether this is due to increased contact pressures on the surrounding articular surface, or if fragment excision causes instability of the elbow. The purpose of this study was to determine if fragment excision of simulated OCD lesions of the capitellum alters kinematics and stability of the elbow.

Method: Nine fresh-frozen cadaveric arms were mounted in an upper extremity joint motion simulator, with cables attaching the tendons of the major muscle tendons to motors and pneumatic actuators. Electromagnetic receivers attached to the radius and ulna enabled quantification of the kinematics of both bones with respect to the humerus. Three-dimensional CT scans were used to plan lesions of 12.5% (mean 0.8cm2), 25%, 37.5%, 50%, and 100% (mean 6.2cm2) of the capitellar surface, which were marked on the capitellum using navigation. Lesions were created by burring through cartilage and subchondral bone. The arms were subjected to active and passive flexion in both the vertical and valgus-loaded positions, and passive forearm rotation in the vertical position.

Results: No significant differences in varus-valgus or rotational ulnohumeral kinematics were found between any of the simulated OCD lesions and the elbows with an intact articulation with active and passive flexion, regardless of forearm rotation and the orientation of the arm (p> 0.7). Radiocapitellar kinematics were not significantly affected during passive forearm rotation with the arm in the vertical position (p=0.07–0.6).

Conclusion: In this in-vitro biomechanical study even large simulated OCD lesions of the capitellum did not alter the kinematics or laxity of the elbow at either the radiocapitellar or ulnohumeral joints. These data suggest that excision of capitellar fragments not amenable to fixation can be considered without altering elbow kinematics or decreasing stability. Further study is required to examine other factors, such as altered contact stresses on the remaining articulation, that are thought to contribute to poorer outcomes in patients with larger lesions.

Purpose: This study evaluated the accuracy of humeral component alignment in total elbow arthroplasty. An image-based navigated approach was compared against a conventional non-navigated technique. We hypothesized that an image-based navigation system would improve humeral component positioning, with navigational errors less than or approaching 2.0mm and 2.0°.

Method: Eleven cadaveric distal humeri were imaged using a CT scanner, from which 3D surface models were reconstructed. Non-navigated humeral component implantation was based on a visual estimation of the flexion-extension (FE) axis on the medial and lateral aspects of the distal humerus, followed by standard instrumentation and positioning of a commercial prosthesis by an experienced surgeon. Positioning was based on the estimated FE axis and surgeon judgment. The stem length was reduced by 75% to evaluate the navigation system independent of implant design constraints. For navigated alignment, the implant was aligned with the FE axis of the CT surface model, which was registered to landmarks of the physical humerus using the iterative closest point algorithm. Navigated implant positioning was based on aligning a 3D computer model calibrated to the implant with a 3D model registered to the distal humerus. Each alignment technique was repeated for a bone loss scenario where distal landmarks were not available for FE axis identification.

Results: Implant alignment error was significantly lower using navigation (P< 0.001). Navigated implant alignment error was 1.2±0.3 mm in translation and 1.3±0.3° in rotation for the intact scenario, and 1.1±0.5 mm and 2.0±1.3° for the bone loss scenario. Non-navigated alignment error was 3.1±1.3 mm and 5.0±3.8° for the intact scenario, and 3.0±1.6 mm and 12.2±3.3° for the bone loss scenario. Without navigation, 5 implants were aligned outside 5° for intact bone while 9 were aligned outside 10° for the bone loss scenario.

Conclusion: Image-based navigation improved the accuracy of humeral component placement to less than 2.0 mm and 2.0°. Further, outliers in implant positioning were reduced using image-based navigation, particularly in the presence of bone loss. Implant malalignment may well increase the likelihood of early implant wear, instability and loosening. It is likely that improved implant positioning will lead to fewer implant related complications and greater prosthesis longevity.

Purpose: The role of the posterior bundle of the medial collateral ligament (PMCL) in stability of the elbow remains poorly defined. The purpose of this study was to determine the effect of sectioning the PMCL on the stability of the elbow.

Method: Varus and valgus gravity-loaded passive elbow motion and simulated active vertical elbow motion were performed on 11 cadaveric arms. An in-vitro elbow motion simulator, utilizing computer-controlled pneumatic actuators and servo-motors sutured to tendons, was used to simulate active elbow flexion. Varus/valgus angle and internal/external rotation of the ulna with respect to the humerus were recorded using an electromagnetic tracking system. Testing was performed on the intact elbow and following sectioning of the PMCL.

Results: With active flexion in the vertical position the varus/valgus kinematics were unchanged after PMCL sectioning (p=0.08). However, with the forearm in pronation, there was a significant increase in internal rotation after PMCL sectioning compared to the intact elbow (p< 0.05) which was most evident at 0° and 120° degrees of flexion (p< 0.05). This rotational difference was not statistically significant with the forearm in supination (p=0.07). During supinated passive flexion in the varus position, PMCL sectioning resulted in increased varus angulation at all flexion angles (p< 0.05). In pronation varus angulation was only increased at 120° of flexion (p< 0.05). However, internal rotation was increased at flexion angles of 30° to 120° (p< 0.05). In supination, sectioning the PMCL had no significant effect on maximum varus-valgus laxity or maximum internal rotation (p=0.1). However, in pronation, the maximum varus-valgus laxity increased by 3.5° (30%) and maximum internal rotation increased by 1.0° (29%) (p< 0.05).

Conclusion: These results indicate that isolated sectioning of the PMCL causes a small increase in varus angulation and internal rotation during both passive varus and active vertical flexion. This study suggests that isolated sectioning of the PMCL may not be completely benign and may contribute to varus and rotation instability of the elbow. In patients with insufficiency of the PMCL appropriate rehabilitation protocols (avoiding forearm pronation and shoulder abduction) should be followed when other injuries permit.

Results: Repeatability of creating motion-based JCS was less than 1 mm and 1° in all directions. The inter-specimen standard-deviations of position and orientation measurements were smaller for the motion-based than for the anatomy-based JCS in every direction and for every specimen (p< 0.006). The ulno-humeral varus angle and internal/external rotation kinematics of active flexion showed less inter-specimen variability when calculated using motion-based JCS (p< 0.05).

Purpose: While computer-assisted techniques can improve the alignment of the implant articulation with the native structure, stem abutment in the intramedullary canal may impede achievement of this alignment. In the current study, the effect of a fixed valgus (6 degree) stemmed humeral component on the alignment of navigated total elbow arthroplasty was investigated. Our hypothesis was that implantation of a humeral component with a reduced stem length would be more accurate than implantation of the humeral component with a standard length stem.

Method: Thirteen cadaveric distal humeri were imaged using a CT scanner, and a 3D surface model was reconstructed from each scan. Implantation was performed using two implant configurations. The first set was unmodified (Regular) while the second set was modified by reducing the length of the humeral stem to 25% of the original stem (Reduced). A surface model of the humeral component was aligned with the flexion-extension (FE) axis of the CT-based surface model, which was registered to the landmarks of the physical humerus using the iterative closest point algorithm. Navigated implant positioning was based on aligning a 3D computer model calibrated to the implant with a 3D model registered to the distal humerus.

Results: Implant alignment error was significantly lower for the Reduced implant, averaging 1.3±0.5 mm in translation and 1.2±0.4° in rotation, compared with 1.9±1.1 mm and 3.6±2.1° for the Regular implant. Abutment of the implant stem with the medullary canal of the humerus prevented optimal alignment of the Regular humeral component as only four of the 13 implantations were aligned to within 2.0° using navigation.

Conclusion: These results demonstrate that a humeral component with a fixed valgus angulation cannot be accurately positioned in a consistent fashion within the medullary canal of the distal humerus without sacrificing alignment of the FE axis due to stem abutment. Improved accuracy of implant placement can be achieved by introducing a family of humeral components, with three valgus angulations of 0°, 4° and 8°. Based on humeral morphology for these specimens, 12 of the 13 implants may be positioned to within 2° of the native FE axis using one of these 3 valgus angulations.

Purpose: Coronal shear fractures of the humerus include the Kocher-Lorenz fracture, an osteochondral fracture of the capitellar articular surface, the Hahn-Steinthal fracture, a substantial shear fragment, extension into the trochlea, and complete involvement of the capitellum and trochlea. If the fracture proves irreparable, it is not known what the impact of fragment excision would have on the biomechanics of the elbow. The purpose of this study was to examine the effect of the sequential loss of the capitellum and trochlea on the kinematics and stability of the elbow.

Method: Eight fresh-frozen cadaveric arms were mounted in an upper extremity joint testing system, with cables attaching the tendons of the major muscles to motors and pneumatic actuators. Electromagnetic receivers attached to the radius and ulna enabled quantification of the kinematics of both bones with respect to the humerus. The distal humeral articular surface was sequentially excised to replicate clinically relevant coronal shear fractures while leaving the collateral ligaments intact. Active flexion in both the vertical and valgus-loaded positions, and passive rotation in the vertical position was conducted for each excision.

Results: Excision of the capitellum had no effect on ulnohumeral stability or kinematics in both the vertical or valgus positions (p=1.0). Excision of the entire capitellum and trochlea led to significant valgus instability with the arm in the valgus position (p=0.01), while excision of the lateral trochlea led to increased valgus instability with pronated flexion in the valgus position (p=0.049). Progressive loss of the articular surface led to posterior, inferior, and medial displacement of the radial head with respect to the capitellum and increased external rotation of the ulna with respect to the humerus in the vertical position (p< 0.05).

Conclusion: Excision of the capitellum did not result in valgus or rotational instability, while excision of the trochlea resulted in multiplanar instability. The radial head displaced medially because it is constrained to the ulna by the annular ligament, and the ulna pivoted into valgus and external rotation on the residual trochlea and medial collateral ligament. In patients with coronal shear fractures, the trochlea must be reconstructed to prevent instability and the potential for secondary degenerative change.

Introduction: Intra-articular steroid injection has long been used to treat osteoarthritis of the knee and hip by orthopaedic surgeons, rheumatologists and general practitioners. Recent literature has shown conflicting results with regard to its safety. We aimed to investigate whether a relationship exists between preoperative intra-articular steroid injection and postoperative infection in total knee arthroplasty (TKA).

Patients and Methods: We reviewed the records of all patients having TKA between April 2005 and April 2007 in University Hospital Aintree, Liverpool. The operations were carried out by 6 consultants. Exclusion criteria for analysis were: previous knee infection, revision knee surgery, fracture around the knee, skin disorders, diabetes, blood transfusion, rheumatoid arthritis and immunosuppressive medication. Eligible patients were divided into two groups: group I had received intra-articular steroid injection (each subject receiving 1–3 (mean 1.6) injections between 1–12 (mean 5) months before TKA); group II had received no injection. Mean follow-up was 17 months.

Results: 425 patients had TKA, of which 361 met our criteria. 121 patients in group I and 240 patients in group II. No-one in group I developed acute infection. In group II, 7 patients developed acute infection (5 superficial and 2 deep) between 1 and 6 weeks (mean 3.7 weeks) post-operatively. There were no late infections. The difference in infection rate between groups I and II was not statistically significant (P=0.1, Fisher’s exact test).

Conclusion: We found no evidence that intra-articular steroid injection prior to TKA increased the incidence of postoperative infection.

A longer stay in the hospital after primary total hip replacement is consistent with an increased morbidity and slower recovery for patients. In addition, it is among the more costly aspects of a total joint replacement. A process, which reduces the length of stay following this procedure and synchronically maintains the high standards of safe care would certainly improve the clinical practice and provide financial benefits.

Our objective was to evaluate the efficiency of a holistic perioperative, accelerated recovery programme following this procedure and in particular to assess its impact in the shot term patient’s recovery, morbidity, complications, readmission rate and cost savings for the NHS.

Eighty-nine patients participated in our rapid recovery programme, which is a comprehensive approach to patient care, combining individual pre-operative patient education, pain management, infection control, continuous nursing and medical staff motivation as well as intensive physiotherapy in the ward and the community. Forty-eight male and 41 female patients with an average age of 69 (range-50 to 87) underwent a total hip replacement in an NHS District General Hospital. The average BMI was 28 (range-18 to 39) and the average ASA 2.3 (range-1 to 4). The procedure was performed by 3 different surgeons using the same operative standards. A standardised post-operative protocol was followed and the patients were discharged when they were medically fit and had achieved the ward physiotherapy requirements. They were then daily followed up by a community orthopaedic rehabilitation team in patient’s own environment as long as it was required.

The average length of stay was reduced from 7.8 days to 5. There was no increase in complications–or readmissions rate while there were significant cost savings. The waiting list for this surgery was reduced and the patient’s satisfaction was high.

The rapid recovery programme for primary total hip replacement surgeries has been proved to be an efficient method of reducing the length of stay in hospital and consequently the financial costs while it ensures the safe and effective peri-operative management of patients.

Introduction: Geometry of the proximal femur has been identified as a risk factors for hip fracture. It is also suggested that the geometry of the proximal femur can influence the fracture type.

Aims: To identify if proximal geometry and hip fractures are related in two different population groups. Scotland–Monklands General Hospital, Lanarkshire–and Australia -Flinders Medical Centre, Adelaide.

Methods: Retrospective comparison of length and width of the femoral necks in 200 hip fracture patients. 100 patients in the Australian group and 100 patients in the Scottish group were analysed. 50 intracapsular and 50 intertrochanteric fractures were included in each group. All measurements where made from standardised digital anteroposterior radiographs. We attempted to correlate the length and width of the femoral neck with the fracture type.

Results: The populations were matched for age and sex, with the majority of fractures sustained by women. The results for the both populations show that a patient sustaining an intracapsular fracture is more likely to have a longer femoral neck (mean 40.56mm; Scottish population, 39mm; Australian population) than one sustaining an intertrochanteric fracture (mean 31.70mm; Scottish population, 29mm; Australian population) [P < 0.0001]. The femoral neck was also narrower in the intracapsular group. This was significant in Scottish population (mean 38.56mm, P < 0.03), but not in the Australian population (mean 38.3mm, P = 0.067). We also found that men had longer, wider femoral necks (P < 0.0001) compared to the female group.

Discussion: We found that hip fracture pattern is linked to proximal femoral geometry. This relationship is statistically significant in both population groups. Anthropologically, as the human race evolves and people get taller, their femoral neck lengths are increasing. This could translate into a change in the number and type of hip fractures. Intracapsular fractures may predominate and this could have implications on both treatment outcomes and resources for hip fracture patients.

Purpose: The aim of this nonrandomised retrospective study was to compare the results of anterior plating with superior plating in acute mid-shaft clavicular fractures.

Method: From 2000–2005, 49 fresh midshaft clavicular fractures in adults with shortening of > 20mm on the radiographs were treated with reconstruction plates. The placement of the plate on the clavicular surface was based on the preference of the surgeon operating. Patients were discharged within a day or two of the operation depending on pain control and were allowed to mobilise their shoulder within pain limits. They were followed up at six weeks and 12 weeks post operation and were allowed to return to work by 12 weeks if there was clinical and radiological signs of union. There were 22 patients in the anterior and 27 in the superior group. The mean age in the anterior was 36.3 years and 37.6 in the superior group. Majority(65%) of the fractures were sustained following RTA.77% were involved on the dominant side in both groups. The percent of patients in light and heavy manual work were similar in both groups. Follow up varied from six months to 24 months. Functional outcome was analysed by the physiotherapist with Biodex machine using Constant score and patient satisfaction questionnaire.

Results: There was no significant difference in Constant scores (Anterior=89, Superior=86), patient satisfaction with operation, return to activity and occupation in either groups. There was a total of six implant removals out of which five were in the superior group due to prominent metalware. There were two implant failures between six to 12 weeks post operation, both of which were in the superior group which were replated anteriorly. There was no significant difference in the deep/superficial infection in either groups. Return to work and satisfaction with operation were similar in both groups.

Conclusion: In our study, the incidence of hardware failure and hardware removal was significantly higher in the superior group compared to anterior group. Necessity for hardware removal becomes low as the anteriorly placed plate is less prominent. Also the risk of injuring the important neurovascular structures is less while drilling holes from anterior to posterior compared to superior to inferior direction. Hence we recommend anterior plating of the clavicle as a better method compared to superior plating of the clavicle.

It is established good practice that joint replacements should have regular follow-up and for the past seven years at the North Hampshire Hospital a local joint register has been used for this purpose and we compare this with results of the Swedish and UK national registries.

Since March 1999, all primary and revision knee arthroplasties performed at North Hampshire Hospital, Basingstoke have been prospectively recorded onto a database set up by one of the senior authors (JMB). Data from patients entered in the first six years of the register were analysed. All patients have at least one year clinical and radiological review then a minimum of yearly postal follow-up.

As of 31/12/2006, 2854 knee replacement procedures had been performed under the care of 13 consultants. OA was the most common diagnosis in over 75% of knees. 5.2% of patients had died and 4.6% were lost to follow-up. Our revision burden was 3.5% and we had a revision rate of 1.4% for primary total knee replacements. Audit of data for revisions and patello-femoral replacements has enabled us to change our practices. Mean length of stay was 7.2 days for primary total knee arthroplasty versus 4.0 days for unicompartmental knee arthroplasty and 5.4 days for patellofemoral replacement and mean flexion at discharge was 88.4, 93.7 and 88.7 degrees respectively. WOMAC and Oxford scores at 2 years had improved from a mean of 52 and 21 pre-operatively to 74 and 39 respectively for primary total knee arthroplasty. Our costs are estimated at approximately £35 per patient for their lifetime on the register.

Compared to other registries:

Our dataset is more complete and comprehensive

Stress shielding (i.e. reduction in bone strains) in the distal ulna is commonly noted following ulnar head replacement arthroplasty. Optimal design parameters for distal ulnar implants, including the length of the stem, are currently unknown. The purpose of this study was to investigate the effect of stem length on bone strains along the length of the ulna.

Strain gauges were applied to each of eight cadaveric ulnae to measure bending loads at six locations along each ulna’s length (approximately 1.5, 2.5, 4.0, 6.0, 8.0, and 13.0cm from the ulnar head). The proximal portion of each bone was secured in a custom-designed jig. A materials testing machine applied loads (5–30N) to the ulnar head while native strains were recorded. The ulnar head was removed and the loading procedure repeated for cemented stainless steel stems 3 and 7cm in length, according to a previously reported technique (Austman et al, CORS 2006). Other stem lengths between 3 and 7cm were tested in 0.5cm intervals with a 20N load applied only. Data were analyzed using a two-way repeated measures ANOVA (á=0.05).

In general, distal bone strains increased as stem length decreased (e.g. average microstrains at the second distal-most gauges: 138±13 (7cm), 147±15 (6cm), 159±21 (5cm), 186±40 (4cm), 235±43 (3cm)). The native strains were different from all stem lengths for the four distal-most gauges (p< 0.05). No differences were found between any stem length and the native bone at the two proximal-most gauges. The 3cm stem replicated the native strains more closely than the 7cm, over all applied loads (e.g. average microstrains at the third gauge level for a 25N load: 357±59 (native), 396±74 (3cm), 257±34 (7cm)).

No stem length tested matched the native strains at all gauge locations. The 3cm stem results were closer to the native strains than the 7cm stem for all loads at gauges overtop of the stem. Overall, the 3cm stem produced the highest strains, and thus would likely result in less distal ulnar bone resorption after implantation. These results suggest that shorter (approximately 3cm) stems should be considered for distal ulnar implants to potentially reduce stress shielding, although this must be balanced by adequate stem length for fixation.

Aim: The purpose of this study was to report the long-term follow-up (mean of 15 years) of patients with displaced intra-articular calcaneal fractures from a randomised controlled trial published in 1993.

Patients and Methods: 46 patients (82% of patients in the initial study group) were alive at a mean of 15 years post injury. The patients had been randomly allocated to either conservative or operative (Soeur and Remy technique) treatment in the original study. Clinical (AOFAS, FFI and calcaneal fracture score) and radiological (Böhler’s angle and calcaneum height) outcome measures were used. The grade of osteoarthritis was also assessed at long-term follow-up.

Results: 26 patients (57%) were reviewed and these patients served as the focus of the study (11 conservative and 15 operative). The clinical outcomes after conservative treatment were not found to be different from those after operative treatment, scores of the AOFAS were 78.5 and 70 respectively (p = 0.11); scores of the FFI were 24.4 and 26.9 respectively (p = 0.66) and calcaneal fracture scores were 70.1 and 63.5 respectively (p = 0.41). The radiological outcomes after conservative treatment were not found to be different from those after operative treatment, Böhler’s angles were 10° and 16° respectively (p = 0.07) and the height of the calcaneum were 37mm and 36mm respectively (p = 0.57). There was no difference in the grade of osteoarthritis between the groups.

Conclusion: The functional and radiological long-term outcomes after conservative treatment of displaced intra-articular calcaneal fractures were equivalent to those after operative treatment. The operative technique showed no benefit compared to conservative treatment at long-term follow-up. There was a trend for higher scores on clinical outcomes with conservative treatment

Introduction: Serum inflammatory markers are routinely used as pre assessment investigation before the revision hip surgery. Various investigations are used to aid in diagnosis of infection in the revision prosthetic hip replacement including aspiration, broad range PCR, bone scan and serum interleukin- 6.

Materials and Methods: 256 consecutive revision total hip replacements were assessed for the value of pre operative ESR and c-reactive proteins (CRP) in predicting the deep infections.

All patients were evaluated prior to surgery. The patients with coexisting inflammatory disease or peri-prosthetic fracture were also evaluated.

A hip was diagnosed as infected on the basis of positive intra operative microbiology samples three or more out of five and or histological evidence.

Results: Using the values of ESR > 35 mm/1^st hour and CRP> 10mg/l, the positive predictive value (either /or) was 56% and the negative predictive value was 96%. 14 patients had an underlying inflammatory arthritis and 5 were peri prosthetic fractures. The inflammatory markers tended to be elevated in these patients. Excluding these 19 patients and using the same criteria, the positive predictive value was 65% and the negative predictive value was 97%

Discussion: We conclude that a CRP< 10 mg/l and ESR < 35 mm/1^st hour are very useful in excluding infection (negative predictive value of 97%, excluding peri-prosthetic fractures and inflammatory joint disease), but raised inflammatory markers are less accurate in predicting infection.

Aims: To determine the anthropometric measurements of bony landmarks in the knee using MR scans and so assist revision knee surgeons in prostheses placement.

Methods: We analysed 100 MR scans of patients aged 16–50 (50 male, 50 female) which were performed for meniscal pathology, patellar dislocation and ACL injury. Those over the age of 50 or with symptoms suggestive of general osteoarthritis, or where the epiphyses had not yet fused were excluded. All measurements recorded were to the level of joint line and are shown below.

Conclusions: To ensure near normal knee mechanics are achieved during revision knee surgery the joint line should be within 5mm of the original. Our study provides mean values for the distance from various bony landmarks to the joint line in non-arthritic knees on MR scan. The use of the medial epicondyle value as a sole reference will place the joint line within 5mm in 88% of males and 96% of females. Use of multiple landmarks further increases accuracy. The final position of the joint will depend on trialling prostheses.

To determine the ten-year survivorship of the Original M E Muller Straight Stem Total Hip Replacement System with emphasis on the longevity of the femoral component in accordance with guidelines published by the National Institute of Clinical Excellence, 266 consecutive hip arthroplasties using the above prosthesis were performed by the senior author between 1983 and 1992. 24 patients were lost to follow-up. Of the remaining 242 patients 80 were male and 162 female. The mean age was 67.49 years. The diagnosis for the majority of patients was osteoarthritis of the hip joint. Pre-operative planning was carried out and the patients were scored using Charnley’s modification of the d’ Aubigne and Postel numerical grading system A mono-bloc stem with a 32-millimeter head used via the trans gluteal approach recommended by Muller. Following discharge serial follow-up consisted of both clinical and radiological evaluation. The data was prospectively stored on a Microsoft access database. The survival of the prosthesis using revision for aseptic loosening as an end-point was calculated by actuarial analysis.

135 patients attended their ten-year follow-up. 97% of patients had good to excellent pain relief and improvement in movement of the joint following surgery. 38% had good to excellent mobility with the remaining having restricted mobility due to associated co-morbid factors. Only in 3% of patients was mobility restricted as a result of the arthroplasty. 7 revisions were carried out for aseptic loosening, all as a result of failure of the acetabular component. The cumulative survival for this hip replacement system was 95.9% and that for the femoral component was 100% at 10 years.

The Muller Straight Stem femoral component is based on a press-fit concept and gives predictable long-term results when recommended surgical technique is followed. This series confirms the reliability of the stem design and satisfies the NICE guidelines.

This in-vitro study was conducted to determine the effect of rotator cuff tears on joint kinematics. A shoulder simulator produced unconstrained active abduction of the humerus. Three sequential 1cm lesions were created, the first two in the supraspinatus tendon and the third in the subscapularis tendon. The plane of abduction moved posteriorly and became more abnormal throughout abduction as the size of the tear increased. It is concluded that in order to generate the same motions achieved by the intact joint other muscle groups must be employed, inevitably resulting in altered joint loading.

This in-vitro study was conducted to determine the effect of simulated progressive tears of the rotator cuff on active glenohumeral joint kinematics.

Five cadaveric shoulders were tested using a shoulder simulator designed to produce unconstrained active motion of the humerus. Forces were applied to simulate loading of the supraspinatus, subscapularis, infraspinatus/teres minor, anterior, middle, and posterior deltoid muscles based upon variable ratios of electromyographic data and average physiological cross-sectional area of the muscles. Three sequential 1cm lesions were created, the first two in the supraspinatus tendon and the third in the subscapularis tendon. Simulated active glenohumeral abduction was performed following the creation of each lesion. Five successive tests were performed to quantify repeatability.

The plane of abduction moved posteriorly and became more abnormal throughout abduction as the size of the lesion increased (p=0.01) (Figure 1).

In order to generate the same motions achieved with an intact rotator cuff other muscle groups must be employed, inevitably resulting in altered joint loading.

A better understanding of the effects that rotator cuff tears have on the kinematics of the glenohumeral joint may result in the development of innovative rehabilitation strategies to compensate for this change in muscle balance and improve the clinical outcomes.

Please contact author for diagram and/or graph.

Introduction We report the early results of a series of 80 primary total knee replacements (TKRs) using a trabecular metal tibial component (TMT).

Methods Significant tibial bone loss and scarcity of kit were the only reasons for patients not receiving a TMT. Age, sex, diagnosis and body mass index (BMI) were recorded. Patients were scored pre-operatively using the Oxford Knee and SF-12 scores. These were repeated at subsequent clinical follow up where standard X-rays were also taken. Range of movement was estimated using a goniometer and stability assessed clinically. This regimen was identical to that in place for the standard knee previously used by the senior author with a cemented tibial component and this group is used in comparison as possible.

Results To date there are 80 TMT knees in the series with 36 standard cemented TKRs in comparison. The mean age of the whole series is 70 years (20–90) with no difference between the groups. Sixty five per cent of the series were female. All bar three patients had osteoarthritis. The mean BMI was 30.3 (20.9–46.2). The mean pre-op Oxford score was 45.8 in the TMT group and 44.5 in the cemented group. At a mean follow up of 13.3 (9–17) months in the TMT group and 18.7 (9–19) months in the cemented group this fell to 22.5 and 20.5 respectively. The physical component of the SF-12 score improved from 27.3 to 40.7 in the TMT group and from 27.5 to 45.5 in the cemented group. There was no statistical difference between the groups using either score. The mean amount of flexion pre-operatively was 106 (65–135) degrees for the series. This was maintained postoperatively at 105 degrees (70–125) with no difference between the groups. There was one deep infection in the cemented group that underwent revision and one non-fatal pulmonary embolus in the cemented group. There were no worrying radiological signs in either group.

Conclusion Trabecular metal is made from elemental tantalum. The TMT is an uncemented component with a truly porous structure for bone ingrowth and a modulus of elasticity equivalent to bone that allows physiological transfer of stresses. The early clinical and radiological results are equal to a cemented prosthesis. Further follow up is required to see whether this is maintained over time.

Among two hundred and twenty hemivertebrae in our files we performed over a period of eighteen years sixty nine hemivertebrae (HV) excision. Only H.V. with evidence of curve progression were operated on. The technique was a one stage anterior and posterior approach plus convex anterior and posterior arthrodesis plus convex posterior instrumentation using in the more recents cases a baby C.D.

Material: The location of the H.V. was thoraco-lumbar in twenty five cases, lumbar in twenty nine and lumbo-sacral in fifteen. Thirty two free, thirty six hemifused and only one fused H.V. were operated on. The sex ratio was 35 males and 34 females. Associarted malformations were numerous. If the rate of visceral associated malformations is rather the same whatever was the location of the H.V. ( 40% ) the number of associated spine malformations decrease from cranial to caudal ( 60% for thoraco-lumbar H.V. versus 13 % for lumbo-sacral H.V.) The mean age at surgery was 3Y 3M ( 1Y- 9Y) with a mean F.U. of 5Y ( 6M-18Y) for the 25 thoraco-lumbar H.V., respectively 3Y3M ( 1Y- 8Y3M) for the mean age at surgery and 5Y ( 1M-17Y5M) for the average F.U.for the 29 lumbar H.V. and 5Y1M (1M-10Y4M) for surgery and 7Y (1M-18Y3M) for F.U. for the remaining 15 lumbo-sacral H.V.

Results: 8 complications were encountered: 4 hardware failures, 1 sepsis, 1 transient paresthesia of the tibial nerve, 1 partial loss of power in the tibialis anterior and 1 valgus deformity following fibular bone grafting. For the 25 thoraco-lumbar H.V. the average scoliosis Cobb angle pre operatively was 38° ( 18°/ 75°) and at F.U. 24° ( 0°/ 76°) . The mean kyphosis Cobb angle was 24° ( -20°/ 54°) pre operatively and 25° (-16°/60°) at F.U. For the 29 lumbar H.V. the mean scoliosis Cobb angle was 35° (16°/58°) pre operatively and 10° (0°/38°) at F.U.The average kyphosis Cobb angle was -2°( -45°/20°) pre operatively and -6° (-42°/22°) at F.U. For the remaining 15 lumbo-sacral H.V. the average scoliosis Cobb angle was 30° (18°/40°) pre operatively and 13° (2°/32°) at F.U. The mean kyphosis Cobb angle was -22°(-54°/0°) pre operatively and -25°(-64°/-8°) at F.U. H.V. excision is in our opinion the best procedure to treat thoraco-lumbar,lumbar and lumbo-sacral H.V. as far as there is evidence of curve progression. The appropriate age to perform this kind of surgery is before three years of age.

We wished to see if Orthopaedic Surgeons are using the current evidence with regard to the use of drains in knee arthroplasty. A questionnaire was faxed to UK members of BASK.

We had a 71. 7% response rate (160 responses out of 223). For primary TKR, 89. 5% always use a drain. 42. 1% removed their drains at between 24 and 48 hours. The commonest reason for using drains was to prevent haematoma or haemarthrosis development.

The study suggests that the majority of BASK members do not practice evidence based medicine with regard to the use of knee drains.