Introduction

Previous studies have demonstrated the need of accurate reduction of ankle syndesmosis. Measurement of syndesmosis is difficult on plain radiographs. Recently, a difference of 2mm in anterior and posterior measurements at incisura of the inferior tibio-fibular joint on CT has been described as a measure of malreduction (depicted as ‘G’ for ease of description). Our practice changed towards routine post operative bilateral CT following syndesmosis fixation to assess the reduction and identify potential problems at an early stage. The aim of this primarily radiological study was to determine if the use of bilateral cross sectional imaging brings additional benefit above the more conventional practice of unilateral imaging.

Introduction

Although total hip arthroplasty is a very successful operation, complications such as: dislocation, aseptic loosening, and periprosthetic fracture do occur. These aspects have been studied in large populations for traditional stem designs, but not for more recent short stems. The design rationale of short stems is to preserve bone stock, without compromising stability. However, due to their smaller bone contact area, high peak stresses and areas of stress shielding could appear in the proximal femur, especially in the presence of atypical bone geometries. In order to evaluate this aspect, we quantified the stress distribution in atypical proximal femurs implanted with a commercially available calcar guided short stem.

A primary goal of revision Total Knee Arthroplasty (rTKA) is restoration of the Joint Line (JL) and Posterior Condylar Offsets (PCO). The presence of a native contralateral joint allows JL and PCO to be inferred in a way that could account for patient-specific anatomical variations more accurately than current techniques. This study assesses bilateral distal femoral symmetry in the context of defining targets for restoration of JL and PCO in rTKA. 566 pre-operative CTs for bilateral TKAs were segmented and landmarked by two engineers. Landmarks were taken on both femurs at the medial and lateral epicondyles, distal and posterior condyles and hip and femoral centres. These landmarks were used to calculate the distal and posterior offsets on the medial and lateral sides (MDO, MPO, LDO, LPO respectively), the lateral distal femoral angle (LDFA), TEA to PCA angle (TEAtoPCA) and anatomic to mechanical axis angle (AAtoMA). Mean bilateral differences in these measures were calculated and cases were categorised according to the amount of asymmetry. The database analysed included 54.9% (311) females with a mean population age of 68.8 (±7.8) years. The mean bilateral difference for each measure was: LDFA 1.4° (±1.0), TEAtoPCA 1.3° (±0.9), AAtoMA 0.5° (±0.5), MDO 1.4mm (±1.1), MPO 1.0mm (±0.8). The categorisation of asymmetry for each measure was: LDFA had 39.9% of cases with <1° bilateral difference and 92.4% with <3° bilateral difference, TEAtoPCA had 45.8% <1° and 96.6% <3°, AAtoMA had 85.7% <1° and 99.8% <3°, MDO had 46.2% <1mm and 90.3% <3mm, MPO had 57.0% <1mm and 97.9% <3mm. This study presents evidence supporting bilateral distal femoral symmetry. Using the contralateral anatomy to obtain estimates for JL and PCO in rTKA may result in improvements in intraoperative accuracy compared to current techniques and a more patient specific solution to operative planning

Introduction. An understanding of anatomic variability can help guide the surgeon on intervention strategies. Well-functioning thumb metacarpophalangeal joints (MCPJ) are essential for carrying out typical daily activities. However, current options for arthroplasty are limited. This is further hindered by the lack of a precise understanding of the geometric variation present in the population. In this paper, we offer new insight into the major modes of geometric variation in the thumb MCP using Statistical Shape Modelling. Methods. Ten participants free from hand or wrist disease or injury were recruited for CT imaging (Ethics Ref:14/LO/1059). 1. Participants were sex matched with mean age 31yrs (range 27–37yrs). Metacarpal (MC1) and proximal phalanx (PP1) bone surfaces were identified in the CT volumes using a greyscale threshold, and meshed. The ten MC1 and ten PP1 segmented bones were aligned by estimating their principal axes using Principal Component Analysis (PCA), and registration was performed to enable statistical comparison of the position of each mesh vertex. PCA was then used again, to reduce the dimensionality of the data by identifying the main ‘modes’ of independent size and shape variation (principal components, PCs) present in the population. Once the PCs were identified, the variation described by each PC was explored by inspecting the shape change at two standard deviations either side of the mean bone shape. Results. For the ten MC1s, over 80% of the variation was described by the first two PCs (Table 1). Figure 1 shows the effect of the variation in PC1. The majority of geometric variation of the ten PP1s was also described by the first two PCs, with PC1 describing 78.9%. Figure 2 shows the effect of this component on the mean bone geometry. Both the distal articulating surface (head) of the MC1 and the proximal articulating surface (base) of the PP1 vary in overall size. However, the MC1 head also varies in shape (curvature), whereas the PP1 base does not appear to undergo noticeable variation in shape. In this study population, smaller MC1 was observed to correlate with a flatter head, whereas the PP1 head shape did not vary with size. Discussion. The flatter MC1 head (smaller height-radius ratio) may have implications for MCPJ instability, and possibly for osteoarthritic degeneration. A recent study predicted similar trends for the first CMC joint. 2. Previous investigation also observed correlation between MC1 head curvature and MCPJ RoM. 3. , which may explain clinical observations of differing thumb movement strategies. This study used a convenience sample and cannot describe a full population's variability, though the high variance captured by only two PCs suggests adequate external validity amongst similar populations. Further confidence would be gained from studying the joint (i.e. single PCA containing both bones), and wider populations. Significance. These data: provide more precise description of anatomic variation; may offer insights into thumb movement strategies and MCPJ osteoarthritic degeneration. 4. ; and support implant design for individuals whose anatomy can bear an anatomic reconstruction. For any figures or tables, please contact the authors directly

Ulnocarpal impaction (UCI) is a common cause of ulnar-sided wrist pain. UCI typically occurs in wrists with positive ulnar variance, which causes altered loading mechanics between the ulnar head, lunate and triquetrum. However, many individuals with positive ulnar variance never develop UCI, and some with neutral or negative ulnar variance do experience UCI. This suggests that other variables contribute to the development of UCI. Suspected culprits include lunate morphology, and dynamic changes with loaded (grip) pronation. If these anatomic variations are contributing to UCI, we expect them to influence functional impairment scores. Therefore, the objective of this study was to evaluate the relationship between radiographic parameters and pre-surgical upper extremity patient-rated outcomes scores (PROS) in patients with a diagnosis of UCI. Retrospective cohort study of patients undergoing ulnar shortening osteotomy or arthroscopic wafer procedure for UCI. Data derived from prospectively collected departmental database that captured demographic, clinical, functional and radiographic information. Radiographic parameters evaluated were: lunate morphology [presence vs. absence of hamate facet; Antuna-Zapico (A-Z) classification], and dynamic changes on grip view [difference in lunate-ulnar head distance (LUD); difference in lunate uncovering index (LUI)]. PROS assessed were QuickDASH and Patient-Rated Wrist Evaluation (PRWE) scores, collected at patient enrolment. ANOVA was used to assess for differences in PROS between A-Z classification groups. Student's t-test was used to assess for differences in PROS based on presence/absence of a hamate facet. Regression analysis evaluated a relationship between change in LUD with grip and PROS, and change in LUI with grip and PROS. Preliminary analysis included 23 wrists, with a mean patient age of 48.9 years [standard deviation (SD) 14.5 years]. Forty-eight percent were male, and the dominant limb was involved in 52.2% of cases. Average QuickDASH and PRWE scores at enrolment were 50.9 (SD 22.2) and 62.2 (SD 22.0), respectively. Assessment of radiographs revealed 17 patients (73.9%) without a hamate facet. Five patients (21.7%) had A-Z Type I lunate morphology, and nine (39.1%) had Type II and Type III morphology, respectively. ANOVA revealed no differences in enrolment QuickDASH (p = 0.185) or PRWE (p = 0.256) scores between A-Z classification groups. Similarly, Student's t-test found no difference based on presence/absence of a hamate facet (QuickDASH p = 0.594; PRWE p = 0.573). Regression analysis revealed no relationship between change in LUD with grip and PROS (QuickDash R2 = 0.020, p = 0.619; PRWE R2 = 0.009, p = 0.733), and no relationship between change in LUI with grip and PROS (QuickDash R2 = 0.000, p = 0.913; PRWE R2 = 0.010, p = 0.722). Preliminary results suggest no relationship between A-Z classification lunate morphology, presence/absence of a hamate facet, change in LUD, or change in LUI and pre-surgical PROS. It is unclear if our findings represent the true relationship between these radiographic parameters and PROS, or reflect our preliminary sample size. Data analysis is ongoing to add clarity to this question

Neurovascular injury during shoulder arthroplasty is uncommon and has been reported to occur in 1–4% of cases. The incidence of nerve abnormalities during intraoperative nerve monitoring during shoulder arthroplasty is substantially higher. However, the rate of false positives with nerve monitoring is high and the clinical significance of these intraoperative findings is unknown. Therefore, the clinical utility of intraoperative nerve monitoring is unproven. Regardless, experience with intraoperative nerve monitoring has allowed us to identify the times during the procedure when measurable nerve dysfunction is most common. Moreover, experience as well as familiarity with reported patient and anatomic risk factors may help reduce the incidence of neurovascular injury. Five rules that will likely help to reduce intraoperative nerve injuries include recognition of reported patient risk factors, knowledge of relevant anatomy and normal anatomic variations, intraoperative identification and protection of at-risk neurovascular structures, limitation of overall operative time and the amount of time with the arm in at-risk positions, and minimization of retraction force. It is likely not possible to completely avoid neurovascular injuries during TSA. However, by following these five rules, the risk of neurovascular injury can be minimised

Introduction. Femoral neck impingement occurs clinically in total hip replacements (THR) when the acetabular liner articulates against the neck of a femoral stem prosthesis. This may occur in vivo due to factors such as prostheses design, patient anatomical variation, and/or surgical malpositioning, and may be linked to joint instability, unexplained pain, and dislocation. The Standard Test Method for Impingement of Acetabular Prostheses, ASTM F2582 −14, may be used to evaluate acetabular component fatigue and deformation under repeated impingement conditions. It is worth noting that while femoral neck impingement is a clinical observation, relative motions and loading conditions used in ASTM F2582-14 do not replicate in vivo mechanisms. As written, ASTM F2582-14 covers failure mechanism assessment for acetabular liners of multiple designs, materials, and sizes. This study investigates differences observed in the implied and executed kinematics described in ASTM F2582-14 using a Prosim electromechanical hip simulator (Simulation Solutions, Stockport, Greater Manchester) and an AMTI hydraulic 12-station hip simulator (AMTI, Watertown, MA). Method. Neck impingement testing per ASTM F2582-14 was carried out on four groups of artificially aged acetabular liners (per ASTM F2003-15) made from GUR 1020 UHMWPE which was re-melted and cross-linked at 7.5 Mrad. Group A (n=3) and B (n=3) consisted of 28mm diameter femoral heads articulating on 28mm ID × 44mm OD acetabular liners. Group C (n=3) and D (n=3) consisted of 40mm diameter femoral heads articulating on lipped 40mm ID × 56mm OD 10° face changing acetabular liners. All acetabular liners were tested in production equivalent shell-fixtures mounted at 0° initial inclination angle. Femoral stems were potted in resin to fit respective simulator test fixtures. Testing was conducted in bovine serum diluted to 18mg/mL protein content supplemented with sodium azide and EDTA. Groups A and C were tested on a Prosim; Groups B and D were tested on an AMTI. Physical examination and coordination measurement machine (CMM) analyses were conducted on all liners pre-test and at 0.2 million cycle intervals to monitor possible failure mechanisms. Testing was conducted for 1.0 million cycles or until failure. An Abaqus/Explicit model was created to investigate relative motions and contact areas resulting from initial impingement kinematics for each test group. Results. Effects of kinematic differences in the execution of ASTM F2582-14 were observed in the four groups based on simulator type (Figure 1) and liner design. The Abaqus/Explicit FEA model revealed notable differences in relative motions and contact points (Figure 2) between specimen components i.e. acetabular liner, femoral head, and femoral stem throughout range of motion. Acetabular liner angular change within shell-fixtures, rim deformation, crack propagation, and metal-on-metal contact between acetabular shell-fixtures and femoral stems were observed as potential failure mechanisms (Figure 3) throughout testing. These mechanisms varied in severity by group due to differing contact stresses and simulator constraints. Significance. Investigating failure mechanisms caused by altered kinematics of in-vitro neck impingement testing, due to influences of simulator type and acetabular liner design, may aid understanding of failure mechanisms involved when assessing complaints/retrievals and influence future prosthetic designs. For any figures or tables, please contact the authors directly

Introduction. Shoulder arthroplasty is used to treat several common pathologies of the shoulder, including osteoarthritis, post-traumatic arthritis, and avascular necrosis. In replacement of the humeral head, modular components allow for anatomical variations, including retroversion angle and head-neck angle. Surgical options include an anatomic cut or a guide-assisted cut at a fixed retroversion and head-neck angle, which can vary the dimensions of the cut humeral head (height, anteroposterior (AP), and superoinferior (SI) diameters) and lead to negative long term clinical results. This study measures the effect of guide-assisted osteotomies on humeral head dimensions compared to anatomic dimensions. Methods. Computed tomography (CT) scans from 20 cadaveric shoulder specimens (10 male, 10 female; 10 left) were converted to three-dimensional models using medical imaging software. An anatomic humeral head cut plane was placed at the anatomic head – neck junction of all shoulders by a fellowship trained shoulder surgeon. Cut planes were generated for each of the standard implant head-neck angles (125°, 130°, 135°, and 140°) and retroversion angles (20°, 30°, and 40°) in commercial cutting guides. Each cut plane was positioned to favour the anterior humeral head-neck junction while preserving the posterior cuff insertion. The humeral head height and diameter were measured in both the AP plane and the SI plane for the anatomic and guide-assisted osteotomy planes. Differences were compared using separate two-way repeated measures ANOVA for each dependent variable and deviations were shown using box plot and whisker diagrams. Results. Guide-assisted cuts tend to be smaller than the anatomic humeral head dimensions. Retroversion angle showed a significant effect on head height, AP, and SI diameters (p=0.002). The effect of head-neck angle was only significant for SI diameter (p<0.001). The largest dimensional deviation was observed at 20 degrees of retroversion and resulted in a 2.5mm decrease in humeral head height, averaged over the range of head-neck values. Conclusion. Where patient's natural anatomy falls outside the range of commercial cutting guides, resection according to the template may result in a deviation from the natural dimensions of the humeral head, which impacts the sizing of the implant head component. This has implications for both manufacturers to create a template that has a larger range of retroversion angles, as well as surgeons' choices in intra-operative planning

The Birmingham hip resurfacing (Smith & Nephew, Tennessee) (BHR) has been used in younger more active patients. Aim. We report on our experience of 206 BHR procedures in patients aged 50 years or less with a minimum ten year follow-up. Clinical outcome scores, body mass index (BMI), gender and age were analysed to investigate resurfacing outcomes. Methods. 200 patients (158 males and 42 females) with an average operation age of 43.33 years (SD ±5.66) were investigated. There were 6 bilateral procedures The mean follow-up period was 12.44 years (SD ±1.71). The arthroplasties were completed between April 1999 and December 2002 by one surgeon. Data and outcome measurements were collected prospectively and analysed retrospectively. We evaluated Harris Hip Scores, Short Form-36 (SF-36v2) Scores, Tegner Activity Score Scores and McMaster Universities Osteoarthritis Index Scores (WOMAC) comparatively at preoperative, six month and yearly intervals. Results. In 1 patient the implant was in situ at the time of death. Revision was carried out in 5 hips (2.4%) at a mean time period of 3.2 years (0–8) post-operatively. Failure was due to femoral neck fracture, acetabular loosening and avascular necrosis of the femoral head, leading to loosening. Kaplan-Meier analysis showed survivorship of 97.6%. The mean Harris Hip scores (paired t-test, p<0.05) improved significantly from 55.58 preoperatively to 91.33 at 15 years. The mean SF-36v2 physical scores (paired t-test, p<0.05) improved significantly from 32.70 preoperatively to 43.75 at 15 years. WOMAC total scores (paired t-test, p<0.05) improved significantly from 44.37 preoperatively to 14.67 at 15 years. Conclusion. In this demanding group of patients, without any restrictions to physical activity, the results of this procedure at 10 years are most encouraging. However, concerns remain in relation to the effect of elevated metal ions, tissue sensitivities, and anatomical variations, such as hip dysplasia, which may impact on function and success

Introduction/Purpose. Total ankle replacement (TAR) success has improved since first-generation implants, but patient satisfaction continues to be less than knee and hip replacements. Little is known about variations in distal tibia anatomy between genders and across ethnicities; therefore it is unclear the extent to which current TAR prostheses accommodate variability in patient size and shape. This study quantified distal tibia morphometrics relevant to TAR design, and assessed differences between ethnicities and genders. The hypotheses were: (1) The anterior-posterior (AP) location of the dwell point of the tibia is centralized; (2) The sagittal radius of curvature of the tibial articulation increases with bone size; (3) Differences in dwell point location or sagittal radii between genders and ethnicities can be attributed to size differences between those populations. Methods. Tibial CT scans were obtained from cadavers or individuals of various ethnicities (Table 1). Landmarks were defined on digital models created from the scans, including medial and lateral edges of the distal tibial articulation (Figure 1a), and sagittal contours of the articulation (Figure 1b). The articulation center was defined as the average center point of all contours (Figure 1c). The AP center and AP length at the level of a distal tibial resection for TAR were determined, and the AP offset of the articulation center was calculated (Figure 1c). Differences in metrics for each ethnic and gender group were determined using a one-way Anova (P<.05) with Tukey's method for differentiating groups. Regression fits of AP offset, average medial radius, and average lateral radius were determined. Utilizing AP length as a covariate, ANCOVA was utilized to assess differences in AP offset and sagittal radii between gender and ethnic groups (P<.05). Results. Descriptive statistics for AP length, AP offset, and medial/lateral radii are shown in Table 1, with Tukey groupings assigned. The relationship between medial and lateral radius was not consistent across all groups. AP length was a significant covariate for medial and lateral radii, but not AP offset. The relationship between lateral radius and AP length was significantly impacted by ethnicity (P<.001), but not by gender (P=.067) (Figure 2a). Medial radius versus AP length was significantly impacted by both ethnicity (P=.01) and gender (P<.03) (Figure 2b). Conclusion. This study illustrates for the first time the complexity of anatomical variation of the distal tibia across ethnic groups and between genders. The location of the articulation center is invariant to tibia size across each ethnicity. Medial and lateral sagittal radii generally increase with bone size, but the relative radii of the medial and lateral compartments are not consistent across ethnicities. These results highlight the need for increased anatomic understanding of the distal tibia, and implications on TAR design and technique

In TKA, prosthetic femoral and tibial implants must be symmetrically placed and matched in the mechanical axis and the ligament gaps must be correctly balanced. The collateral ligaments are the key guide, as they arise from the epicondyles of the distal femur, are perpendicular to the AP axis of Whiteside, and are coincident with the transtibial axis of the proximal tibial surface. A perpendicular bisection of the transtibial axis creates the AP axis of the tibia which is coincident in space with the AP axis of Whiteside (Berger). Measured distal femoral resection targets including TEA, AP axis of Whiteside, and 3 degrees external to the posterior condylar axis works because the stout posterior cruciate ligament limits laxity in flexion, allowing for the anatomical variation of these landmarks to be accommodated. The Insall, Ranawat gap balancing methods work to balance the knee in flexion, often matching the results of a measured resection, but guaranteeing a symmetrically balanced flexion gap. Distal femoral internal rotation can result if the medial collateral is over-released, but experience has shown this not to be a problem if the gaps are well balanced. Tibial tray position must be placed coincident with the AP axis of the tibia, which also is coincident with Akagi's line (line from medial margin of patellar tendon to center of the posterior cruciate ligament). The surgeon can make a line from the AP axis of Whiteside to the anterior tibial which matches the AP tibial axis

Introduction. Valgus knees are generally more difficult to get acceptable alignment and balance than the varus knee. Most of these are due to anatomical variations in both the diaphysis of the femur, with low valgus angles (angle between the anatomic and mechanical axis of the femur) and the tibial diaphysis. In addition there are those with dysplastic lateral distal femoral condyle s and low external femoral angles (below 84 degrees). Aim. To assess the clinical results, patient satisfaction and alignment and balance achieved in those with a pre-operative mechanical valgus above 10 degrees. Method. There were 1038 Total Knee Replacements (TKR) performed by one surgeon from 2006 to 2012. 274 (26%) had valgus mechanical alignments pre operatively, and of this group there were 84 (31%) that had mechanical axis (MA) > 9degrees. Long leg X-rays were used to assess pre and post-operative and component alignment. Patients were assessed by means of the Knee Society Score and a satisfaction rating. Results. 64% had a post-operative MA < 4 degrees, 34% were between 4 and 6 and 2% > 6 degrees. 89%, 85% and 100% reported knee satisfaction respectively for these 3 groups. The valgus knees in this series with a pre-operative MA = 9 degrees had a satisfaction rate of 90%. Discussion. Severe valgus knees can be adequately corrected and balanced but need significant release or relative lengthening of the LCL by epicondylar osteotomy. Final alignment did / did not affect outcome or satisfaction. NO DISCLOSURES

Hip impingement causes clinical problems for both the native hip, where labral or chondral damage can cause severe pain, and in the replaced hip, where subluxation can cause squeaking/metallosis through edge loading, or can cause dislocation. There is much research into bony/prosthetic hard impingements showing that anatomical variation/component mal-positioning can increase the risk of impingement. However, there is a lack of basic science describing the role of the hip capsule and its intertwined ligaments in restraining range of motion, ROM, and so it is unclear if careful preservation/repair of the capsular ligaments would offer clinical benefits to young adults, or could also help prevent edge loading in addition to reducing the postoperative dislocation rate in older adults. This in-vitro study quantifies the ROM where the capsule passively stabilises the hip and compares this to hip kinematics during daily activities at risk for hip subluxation. Ten cadaveric left hips were skeletonised preserving the joint capsule and mounted in a testing rig that allowed application of loads, torques and rotations in all six-degrees of freedom (Figure 1). At 27 positions encompassing a complete hip ROM, the passive rotation resistance of each hip was recorded. The gradient of the torque-rotation profiles was used to quantify where the capsule is taut/slack and after resecting the capsule, where labral impingement occur. The ROM measurements were compared against hip kinematics from daily activities. The capsule tightly restrains the hip in full flexion/extension with large slack regions in mid-flexion. Whilst ligament recruitment varies throughout hip ROM, the magnitude of restraint provided is constant (0.82 ± 0.31 Nm/degree). This restraint acts to prevent or reduce loading of the labrum in the native hip (Figure 2). The measured passive rotational stability envelope is less than clinical ROM measurements indicating the capsule does provide restraint to the joint within a relevant ROM. Activities such as pivoting, stooping, shoe tying and rolling over in bed all would recruit the capsular ligaments in a stabilising role. The fine-tuned anatomy of the hip capsule provides a consistent contribution to hip rotational restraint within a functionally relevant ROM for normal activities protecting the hip against impingement. Capsulotomy should be kept to a minimum and routinely repaired in the native hip to maintain natural hip mechanics. Restoring its native function following hip replacement surgery may provide a method to prevent subluxation and edge loading in the replaced hip

Introduction. Using the tibial extramedullary guide needs meticulous attention to accurately align the tray in total knee arthroplasty (TKA). We previously reported the risk for varus tray alignment if the anteroposterior (AP) axis of the ankle was used for the rotational direction of the guide. The purpose of our study was to determine whether aligning the rotational direction of the guide to the AP axis of the proximal tibia reduced the incidence of varus tray alignment when compared to aligning the rotational direction of the guide to the AP axis of the ankle. Materials and Methods. Clinical Study. A total of 80 osteoarthritis (OA) knees after posterior stabilized TKA were recruited in this study. From 2002 to 2004, the rotational alignment of the guide was adjusted to the AP axis of the ankle (Method A: Figure 1, N = 40 knees). After 2005, the rotational alignment of the guide was adjusted to the AP axis of the proximal tibia (Method B: Figure 1, N = 40 knees). The AP axis of the proximal tibia was defined as the line connecting the middle of the attachment of the PCL and the medial third border of the attachment of the patellar tendon. The guide was set at a level of 10 mm distal to the lateral articular surface. Postoperative alignment was compared between the two groups using full-lengthanteroposterior radiograph. Computer simulation. Computer simulation was performed to determine the effect of ankle rotation on tibial tray alignment, using three-dimensional bone and skin model reconstructed from CT images of 75 OA knees (Figure 2). The position of the distal end of the guide in Method B was evaluated on the coronal plane perpendicular to the AP axis of the proximal tibia and of the ankle respectively. <Displacement> was the distance from the distal end of the guide to the midpoint-malleolar points (+: medial position). <Distance ratio> was the ratio of <Displacement> dividing by the entire width of the malleolar. Results. The results of the postoperative alignment for both methods from the clinical study are shown in Table 1. The number of the knees with more than 3 degrees of varus aligned tibial component significantly decreased with the Method B from the Method A. The computer simulation showed that the position of the guide varied great among individuals in the direction of the AP axis of the ankle joint. Discussion. When an extramedullary alignment guide is used in TKA, a rotational mismatch between the proximal part of the tibia and the ankle joint can induce a varus alignment of the tibial component. Computer simulation also supported our conclusion that the surgeon should not evaluate the distal end of the guide in the direction of the ankle joint to minimize the effects of anatomic variation for proper coronal alignment

The Parva stem has been designed in order to achieve a good cervical and interthrocanteric primary fixation associated with a reliable fit at the isthmus level. The stem has been conceived to address the larger possible variety of proximal femoral anatomic variations too. Ability to adapt to patients anatomies being one of the major limitations of earlier neck preserving implants. The stem therefore features innovative design concepts including the latest generation Modular Neck System, coupled with a revolutionary metal powder manufacturing process and surface engineering technology. Our first 150 cases with minimum 1 year follow up are presented. All patients have been followed employing the Harris Hip Score and the reduced WOMAC questionnaire to judge their degree of satisfaction. Particular care has been posed to analyze results for those patients anatomies (i.e. Very Valgus or Varus femurs) where normally neck sparing stems have problems to correctly fit in. The feed-back we had with this very innovative implant is very encouraging. Further data collection and longer follow up will be needed in order to confirm these early promising results

Purpose of our study is to present the design rationale and the early clinical results for the Parva Stem, an innovative short hip stem. The Parva implant has been designed in order to address the bone sparing concept of a short stem able to achieve a good cervical and interthrocanteric primary fixation associated with a the reliable primary fixation the isthmus level. The stem has been designed to address the larger possible variety of anatomical variations too. The stem therefore features innovative design concepts including the latest generation Modular Neck System, coupled with a revolutionary manufacturing process and surface engineering technology. This manufacturing process (Powder manufacturing Technology) and Ingrowth Surface (Ti-Por) will be also briefly discussed in the presentation. Our early clinical results will be also presented (150 stem-one yr. maximum follow up will be presented) although they are not the main purpose of our study oriented more on the novel design and technological manufacturing advancement. The feed-back we had so far with this state of the art implant is extremely encouraging. Of course further data collection and longer follow up will be needed in order to confirm these early promising results

Introduction. Anatomical reconstruction of the Anterior Cruciate Ligament (ACL) reconstruction has been shown to be desirable and improve patient outcome. The posterior border of the anterior horn of the lateral meniscus (AHLM) is an easily identifiable arthroscopic landmark, which could guide anatomic tibial tunnel position in the sagital plane. The aim of the study was to establish the relationship between the posterior border of AHLM and the centre of the ACL foot print to facilitate anatomical tibial tunnel placement. Materials/Methods. We analysed 100 knee MRI scans where there was no ACL or lateral meniscal injury. We measured the distance between the posterior border of the AHLM and the midpoint of the tibial ACL footprint in the sagital plane. The measurements were repeated 2 weeks later for intra-observer reliability. Results. The mean distance between the posterior border of the AHLM and the ACL midpoint was −0.1mm (i.e. 0.1mm posterior to the ACL midpoint). The range was 5mm to −4.6mm. The median value was 0.00mm. 95% confidence interval was from 0.3 mm to −0.5 mm. A normal, parametric distribution was observed and Intra-observer variability showed significant correlation (p=0.01) using Pearsons Correlation test. Conclusion. Using the posterior border of the AHLM is a reliable, reproducible and anatomic marker for the midpoint of the ACL footprint in the majority of cases. It can be used intra-operatively as a guide for tibial tunnel and graft placement allowing anatomical reconstruction. There will inevitably be some anatomical variation. Pre-operative MRI assessment of the relationship between AHLM and ACL footprint is advised to improve surgical planning

Background. The transverse skin incision for anterior cervical spine surgery is not extensile, thus it must be made at the accurate level. The use of palpable bony landmarks is unreliable due to anatomical variations and pre-operative fluoroscopy to identify the level takes up operating room time, increases the radiation dose to the patient and increases the overall cost of the operation. Objective. To describe a simple, fast and inexpensive method of accurate transverse skin incision placement for anterior cervical spine surgery and to report on its use in 54 consecutive adult patients. Patients and Methods. In each case a ratio was recorded on the lateral cervical spine radiograph based on the distance between the clavicle and mandible and the operative level; this was then applied to measurements on the patient's neck. Results. Procedures performed consisted of a mix of discectomy and fusion, disc replacement and combinations of both. The operative level ranged from C2-C3 to C7-T1, the most common being C5-C6. Twenty-three patients had a single-level, 26 a two level and 5 a three level procedure; all cases were performed through one single transverse incision. Conclusion. We describe the highly successful use of a straightforward method for accurate level transverse skin incision placement for cervical spine surgery In no case was it necessary to radically extend or to make a separate incision. There were no cases where the wrong level was operated on

Purpose. Intramedullary fixation of clavicle fractures requires an adequate medullary canal to accommodate the fixation device used. This computer tomography anatomical study of the clavicle and its medullary canal describes its general anatomy and provides the incidence of anatomical variations of the medullary canal that complicates intramedullary fixation of midshaft fractures. Methods. Four hundred and eighteen clavicles in 209 patients were examined using computer tomography imaging. The length and curvatures of the clavicles were measured as well as the height and width of the clavicle and its canal at various pre-determined points. The start and end of the medullary canal from the sternal and acromial ends of the clavicle were determined. The data was grouped according to age, gender and lateralization. Results. The average length of the clavicle was 151.15mm with the average sternal and acromial curvature being 146° and 133° respectively. The medullary canal starts on average 6.59mm from the sternal end and ends 19.56mm from the acromial end with the average height and width of the canal at the middle third being 5.61mm and 6.63mm respectively. Conclusion. The medullary canal of the clavicle is large enough to accommodate commonly used intramedullary devices in the majority of cases. The medullary canal extends far enough medially and laterally to ensure that an intramedullary device can be passed far enough medially and laterally past the fracture site to ensure stable fixation in most middle third clavicle fractures. An alternative surgical option should be available in theatre when treating females as the medullary canal is too small to pass an intramedullary device past the fracture site on rare occasions. Fractures located within 40mm of the lateral or medial ends of the clavicle should not be treated by intramedullary fixation as adequate stability is unlikely to be achieved. MULTIPLE DISCLOSURES

Controversy surrounds the aetiology of obstetric brachial plexus lesions. Most authors consider that it is caused by traction or compression of the brachial plexus during delivery. Some patients, however, present without a history of major traction during delivery, and some delivered by Caesarean section also suffer the injury. In our series of 42 infants, 28 had an Erb’s palsy, and the remaining 14 presented with a more extensive lesion, involving the lower roots. In five of these, a complete ossified cervical rib was found. We believe that anatomical variations, such as cervical ribs or fibrous bands, can cause narrowing of the supracostoclavicular space, and render the adjacent nerves more susceptible to external trauma