Introduction

Flexor sheath infections require prompt diagnosis, and management with intravenous antibiotics and/or surgical washout followed by physiotherapy. Complication rates as high as 38% have been reported.

The purpose of this study was to determine long-term survival free from all-cause revision and stem-related failure, as well as radiographic and functional outcomes of the ZMR stem in revision THA.

We retrospectively identified all patients in our institutional database who underwent revision THA using the ZMR Revision Hip system from the year 2000 to 2007 (minimum two-year follow-up). Of the 112 ZMR hips (110 patients) identified, a total of 106 hips (104 patients) met inclusion criteria. The mean study follow-up 13.9 years (range 2–22). Indications for index ZMR revision included aseptic loosening (72.1%), periprosthetic joint infection (17.3%), periprosthetic fracture (9.6%), and stem fracture (1.0%). Kaplan-Meier analysis was used to determine the all-cause and stem-related failure revision-free survival. Validated patient reported outcomes were collected and available radiographs were reviewed to determine implant stability.

A total of 17 hips (16.0%) underwent a re-revision of any component. The indications for re-revision were stem failure (35.3%), infection (29.4%), instability (29.4%), and aseptic loosening of the acetabular component (5.9%). The five- and 15-year all-cause survivorship was 89.5% (95% CI 86.5–92.5) and 83.0% (95% CI 79.2–86.8), respectively. There were six re-revisions for stem failure (5.7%); five for stem fracture and one for aseptic loosening. The average time to stem failure was 4.6 years (range 1.3–8.2). The five- and 15-year survivorship free from stem-related failure was 97.2% (95% CI 95.6–98.8) and 93.9% (95% CI 91.5–96.3), respectively. At final follow-up the mean Oxford hip score was 36.9 and all surviving ZMR stems were well fixed on radiographs.

Femoral revision with the ZMR stem offers satisfactory long-term survivorship and promising clinical outcomes. Although uncommon, stem fracture was the most common reason for stem-related failure.

Aims

The aim of this study was to describe services available to patients with periprosthetic femoral fracture (PPFF) in England and Wales, with focus on variation between centres and areas for care improvement.

Aims

Hip resurfacing remains a potentially valuable surgical procedure for appropriately-selected patients with optimised implant choices. However, concern regarding high early failure rates continues to undermine confidence in use. A large contributor to failure is adverse local tissue reactions around metal-on-metal (MoM) bearing surfaces. Such phenomena have been well-explored around MoM total hip arthroplasties, but comparable data in equivalent hip resurfacing procedures is lacking. In order to define genetic predisposition, we performed a case-control study investigating the role of human leucocyte antigen (HLA) genotype in the development of pseudotumours around MoM hip resurfacings.

A hip fracture represents the extreme end of osteoporosis, placing a significant burden on secondary care, society, and the individual patient. The National Hip Fracture Database (NHFD) reports each hospital's attainment of the BPT with other measures, along with reporting outcomes. There is clearly wide variability in provision of orthogerriatrician (OG) services across the dataset. Unfortunately, despite overwhelming evidence that provision of an OG service is of benefit, it is presently challenging to recruit to this important specialty within the UK.

Publicly available reports from the NHFD were obtained for each of the 177 participating hospitals for 2017. This was matched with information held within the annual NHFD Facilities Audit for the same period, which include hours of OG support for each hospital. This information was combined with a Freedom of Information request made by email to each hospital for further details concerning OG support. The outcome measures used were Length of Stay (LoS), mortality, and return to usual residence. Comparison was made with provision of OG services by use of Pearson's correlation coefficient. In addition, differences in services were compared between the 25% (44) hospitals delivering outcomes at the extremes for each measure.

Attainment of BPT correlated fairly with LoS (−0.48) and to less of a degree with mortality (−0.1) and return home (0.05). Perioperative medical assessment contributed very strongly with BPT attainment (0.75). In turn perioperative medical assessment correlated fairly with LoS (−0.40) and mortality (−0.23) but not return home (0.02). Provision of perioperative medical assessment attainment was correlated fairly with total OG minutes available per new patient (0.22), total OG minutes available per patient per day (0.29) and number of days per week of OG cover (0.34); with no link for number of patients per orthogeriatrician (0.01). Mortality for the best units were associated with 30% more consultant OG time available per patient per day, and 51% more OG time available per patient. Units returning the most patients to their usual residence had little association with OG time, although had 59% fewer patients per OG, the best units had a 19% longer LoS. For all three measures results for the best had on average 0.5 days per week better routine OG access.

There is no doubt that good quality care gives better results for this challenging group of patients. However, the interaction of BPT, other care metrics, level of OG support and patient factors with outcomes is complex. We have found OG time available per patient per day appears to influence particularly LoS and mortality. Options to increase OG time per patient include reducing patient numbers (ensuring community osteoporosis/falls prevention in place, including reducing in-patient falls); increasing OG time across the week (employing greater numbers/spreading availability over 7 days per week); and reducing LoS. A reduction in LoS has the largest effect of increasing OG time, and although it is dependent on OG support, it is only fairly correlated with this and many other factors play a part, which could be addressed in units under pressure.

Aims

Within healthcare, several measures are used to quantify and compare the severity of health conditions. Two common measures are disability weight (DW), a context-independent value representing severity of a health state, and utility weight (UW), a context-dependent measure of health-related quality of life. Neither of these measures have previously been determined for developmental dysplasia of the hip (DDH). The aim of this study is to determine the DW and country-specific UWs for DDH.

Aims

Despite multiple trials and case series on hip hemiarthroplasty designs, guidance is still lacking on which implant to use. One particularly deficient area is long-term outcomes. We present over 1,000 consecutive cemented Thompson’s hemiarthroplasties over a ten-year period, recording all accessible patient and implant outcomes.

Aims

Orthopaedic surgeries are complex, frequently performed procedures associated with significant haemorrhage and perioperative blood transfusion. Given refinements in surgical techniques and changes to transfusion practices, we aim to describe contemporary transfusion practices in orthopaedic surgery in order to inform perioperative planning and blood banking requirements.

Aims

The purpose of our study was to determine which groups of orthopaedic providers favour virtual care, and analyze overall orthopaedic provider perceptions of virtual care. We hypothesize that providers with less clinical experience will favour virtual care, and that orthopaedic providers overall will show increased preference for virtual care during the COVID-19 pandemic and decreased preference during non-pandemic circumstances.

Understanding the long-term effects of total knee arthroplasty (TKA) on joint kinematics is vital to assess the success of the implant design and surgical procedure. However, while in vitro cadaveric studies quantifying post-operative biomechanics primarily reflect joint behaviour immediately after surgery,¹in vivo studies comprising of follow-up TKA patients often reflect joint behaviour a few months after surgery.² Therefore, the aim of this cadaveric study was to explore the long-term effects of TKA on tibiofemoral kinematics of a donor specimen, who had already undergone bilateral TKA, and compare them to post-operative kinematics reported in the literature.

Two fresh-frozen lower limbs from a single donor (male, age: 83yr, ht: 1.83m, wt: 86kg), who had undergone bilateral TKA (Genesis II, Smith&Nephew, Memphis, USA) 19 years prior to his demise, were obtained following ethical approval from the KU Leuven institutional board. The specimens were imaged using computed tomography (CT) and tested in a validated knee simulator³ replicating active squatting and varus-valgus laxity tests. Tibiofemoral kinematics were recorded using an optical motion capture system and compared to various studies in the literature using the same implant – experimental studies based on cadaveric specimens (CAD)^1,4 and an artificial specimen (ART)⁵, and a computational study (COM)⁶.

Maximum tibial abduction during laxity tests for the left leg (3.54°) was comparable to CAD (3.30°), while the right leg exhibited much larger joint laxity (8.52°). Both specimens exhibited valgus throughout squatting (left=2.03±0.57°, right=5.81±0.19°), with the change in tibial abduction over the range of flexion (left=1.89°, right=0.64°) comparable to literature (CAD=1.28°, COM=2.43°). The left leg was externally rotated (8.00±0.69°), while the right leg internally rotated (−15.35±1.50°), throughout squatting, with the change in tibial rotation over the range of flexion (left=2.61°, right=4.79°) comparable to literature (CAD=5.52°, COM=4.15°). Change in the femoral anteroposterior translation over the range of flexion during squatting for both specimens (left=14.88mm, right=6.76mm) was also comparable to literature (ART=13.40mm, COM=20.20mm).

Although TKA was reportedly performed at the same time on both legs of the donor by the same surgeon, there was a stark difference in their post-operative joint kinematics. A larger extent of intraoperative collateral ligament release could be one of the potential reasons for higher post-operative joint laxity in the right leg. Relative changes in post-operative tibiofemoral kinematics over the range of squatting were similar to those reported in the literature. However, differences between absolute magnitudes of joint kinematics obtained in this study and findings from the literature could be attributed to different surgeons performing TKA, with presumable variations in alignment techniques and/or patient specific instrumentation, and the slightly dissimilar ranges of knee flexion during squatting.

In conclusion, long-term kinematic effects of TKA quantified using in vitro testing were largely similar to the immediate post-operative kinematics reported in the literature; however, variation in the behaviour of two legs from the same donor suggested that intraoperative surgical alterations might have a greater effect on joint kinematics over time.

Orthopaedic training sessions, vital for surgeons to understand post-operative joint function, are primarily based on passive and subjective joint assessment. However, cadaveric knee simulators, commonly used in orthopaedic research,¹ could potentially benefit surgical training by providing quantitative joint assessment for active functional motions. The integration of cadaveric simulators in orthopaedic training was explored with recipients of the European Knee Society Arthroplasty Travelling Fellowship visiting our institution in 2018 and 2019. The aim of the study was to introduce the fellows to the knee joint simulator to quantify the surgeon-specific impact of total knee arthroplasty (TKA) on the dynamic joint behaviour, thereby identifying potential correlations between surgical competence and post-operative biomechanical parameters.

Eight fellows were assigned a fresh-frozen lower limb each to plan and perform posterior-stabilised TKA using MRI-based patient-specific instrumentation. Surgical competence was adjudged using the Objective Structured Assessment of Technical Skills (OSATS) adapted for TKA.² All fellows participated in the in vitro specimen testing on a validated knee simulator,³ which included motor tasks – passive flexion (0°-120°) and active squatting (35°-100°) – and varus-valgus laxity tests, in both the native and post-operative conditions. Tibiofemoral kinematics were recorded with an optical motion capture system and compared between native and post-operative conditions using a linear mixed model (p<0.05). The Pearson correlation test was used to assess the relationship between the OSATS scores for each surgeon and post-operative joint kinematics of the corresponding specimen (p<0.05).

OSATS scores ranged from 79.6% to 100% (mean=93.1, SD=7.7). A negative correlation was observed between surgical competence and change in post-operative tibial kinematics over the entire range of motion during passive flexion – OSATS score vs. change in tibial abduction (r=−0.87; p=0.003), OSATS score vs. change in tibial rotation (r=−0.76; p=0.02). When compared to the native condition, post-operative tibial internal rotation was higher during passive flexion (p<0.05), but lower during squatting (p<0.033). Post-operative joint stiffness was greater in extension than in flexion, without any correlation with surgical competence.

Although trained at different institutions, all fellows followed certain standard intraoperative guidelines during TKA, such as achieving neutral tibial abduction and avoiding internal tibial rotation,⁴ albeit at a static knee flexion angle. However, post-operative joint kinematics for dynamic motions revealed a strong correlation with surgical competence, i.e. kinematic variability over the range of passive flexion post-TKA was lower for more skilful surgeons. Moreover, actively loaded motions exhibited stark differences in post-operative kinematics as compared to those observed in passive motions. In vitro testing on the knee simulator also introduced the fellows to new quantitative parameters for post-operative joint assessment.

In conclusion, the inclusion of cadaveric simulators replicating functional joint motions could help quantify training paradigms, thereby enhancing traditional orthopaedic training, as was also the unanimous opinion of all participating fellows in their positive feedback.

Introduction

THA for patient's 50 years and younger is a procedure at high risk for complications and failure because of the high level of activity of this population. Highly cross linked polyethylene (HXLPE) has greatly improved the durability of the implant because of the improved wear characteristics. Few studies have followed this population into the second decade and therefore the purpose of this investigation was to evaluate the clinical outcome for the patients 5o years of age and younger at a minimum of 15 years. The second purpose was to evaluate the radiographic findings secondary to wear or mechanical failure of the implant.

Introduction

Our objective is to describe early and midterm results with the use of a new knee prosthesis as an articulating spacer in planned two-stage management for infected total knee arthroplasty. As a second objective, we compared outcomes between the group with a retained first stage and those with a completed 2-stage revision.

Introduction

Spinopelvic mobility has been associated with THA outcome. To-date spine assessments have been made quasi-statically, using radiographs, in standing and seated positions but dynamic spinopelvic mobility has not been well explored. This study aims to determine the association between dynamic (motion analysis) and quasi-static (radiographic) sagittal assessments and examine the association between axial and sagittal spinal kinematics in hip OA patients and controls.

Aims

Extracellular matrix (ECM) and its architecture have a vital role in articular cartilage (AC) structure and function. We hypothesized that a multi-layered chitosan-gelatin (CG) scaffold that resembles ECM, as well as native collagen architecture of AC, will achieve superior chondrogenesis and AC regeneration. We also compared its in vitro and in vivo outcomes with randomly aligned CG scaffold.

Aims

Our rural orthopaedic service has undergone service restructure during the COVID-19 pandemic in order to sustain hip fracture care. All adult trauma care has been centralised to the Royal Shrewsbury Hospital for assessment and medical input, before transferring those requiring operative intervention to the Robert Jones and Agnes Hunt Orthopaedic Hospital. We aim to review the impact of COVID-19 on hip fracture workload and service changes upon management of hip fractures.

Acromioclavicular joint is an integral component of Shoulder Complex and common site of injury particularly for athletes involved in sports such as Football, Cricket, Rugby and Shotput. Acromioclavicular Injuries are often neglected and goes untreated especially in low demand patients. Classic surgical techniques are associated with high complication rates.

This is a prospective study from 2015–2017 wherein 32 patients with Acute grade 3, 4, 5, 6 Acromioclavicular joint dislocations, were operated with Minimally Invasive Double Tunnel Anatomical Coraco-clavicular Ligament Reconstruction (DT-ACCLR) with Tightrope Suspensory fixation. Clinical Outcomes were evaluated with Visual Analog Scale, Constant functional scale, Start of Movement, Return to Work, Satisfaction index and Coraco-clavicular distance over 12 months.

Mean follow-up was 14 ± 3.8 months. Visual analog scale and Constant scores revealed significant advancements 0 ± 0.5 (range, 0–2) and 95 ± 3 (range, 92–98) scores at 12 months respectively. The coraco-clavicular distance significantly reduced from 23 ± 2.4 mm to 8 ± 0.5 mm. Mean return to work by 7 days. 98.6% patients were satisfied with surgical results.

We conclude that DT-ACCLR is simple and creative surgical technique which provides stable, reliable and painless AC joint. The patients can move the shoulder same day and return to Work by 5–7days and Sports 3–4 weeks.

Osteochondroplasty procedure for cam deformity provides excellent outcomes on alleviating pain, improving quality of life and clinical function in femoroacetabular impingement syndrome (FAIS) patients. Although medium-term outcomes on gait biomechanics have been reported, it is unclear how it would translate to better hip muscle forces and joint loading in high range of motion tasks. The purpose of this study was to compare the muscle forces and hip joint contact forces (HCF) during a squat task in individuals before and after cam-FAIS surgical correction. Ten cam-FAIS patients prior and 2-years after osteochondroplasty, and 10 BMI- age- and sex-matched healthy control participants (CTRL) underwent 3D motion and ground reaction forces capture while performing a deep squatting task. Muscle and HCF were estimated using musculoskeletal modeling and comparisons were done using statistical parametric mapping (SPM).

Postoperatives squatted down with a higher anterior pelvic tilt and higher hip flexion compared with the preoperatives. Preoperative semimembranosus generated lower forces than the two other groups on the squat ascending, with no differences detected between post-ops and CTRLs. Preoperatives also showed reduced forces for the distal, ischial and medial portions of the adductor magnus relative to the CTRLs, which although reduced, still presented differences postoperatively. Preoperative anterior and medial contact forces were significantly lower than the CTRL group during both phases of the squat. Postoperative vertical and medial forces were also lower compared to the CTRLs. However, with higher vertical forces during the ascent phase of the squat compared to the preoperative, the postoperative group, significantly increased its HCF magnitude. A higher anterior pelvic tilt was associated with an innate restoration of the pelvis position, once the cam deformity no longer existed. The increased force of the semimembranosus muscle while ascending the squat generated higher vertical HCF, which also influenced the increased HCF total magnitude.

For any tables or figures, please contact the authors directly.

Introduction

The number of medial unicompartmental knee replacements (UKR) performed for arthritis has increased and as such, revisions to total knee replacement (TKR) is increasing. Previous studies have investigated survivorship of UKR to TKR revision and functional outcomes compared to TKR to TKR revision, but have failed to detail the surgical considerations involved in these revisions. Our objectives are to investigate the detailed surgical considerations involved in UKR to TKR revisions.

Introduction

The practice of overlapping surgery has been increasing in the delivery of orthopaedic care, aiming to provide efficient, high-quality care. However, there have been concerns about the safety of this practice. The purpose of this study is to examine safety and efficacy of a model of partially overlapping surgery that we termed “the swing room” in practice in primary hip and knee arthroplasty.

Introduction

Meaningful clinical improvement as demonstrated through patient-reported outcome measures (PROMs) are increasingly used to evaluate success of total hip arthroplasty (THA) procedures. This patient perspective can provide a full picture when used with clinical data to best evaluate surgical outcomes.

Background

Fully constrained liners are used to treat recurrent dislocations or patients at high risk after total hip replacements. However, they can cause significant morbidities including recurrent dislocations, infections, aseptic loosening and fractures. We examine long term results of 111 patients with tripolar constrained components to assess their redislocation and failure rate.

Background

High complication rates and poor outcomes have been widely reported in patients undergoing revision of large head metal-on-metal arthroplasty. A previous study from our center showed high rates of dislocation, nerve injury, early cup loosening and pseudotumor recurrence. After noting these issues, we implemented the following changes in surgical protocol in all large head MOM revisions: 1. Use of highly porous shells in all cases 2. Use of largest femoral head possible 3. Low threshold for use of dual mobility and constrained liners when abductors affected or absent posterior capsule 4. Use of ceramic head with titanium sleeve in all cases 5. Partial resection of pseudotumor adjacent to sciatic and femoral nerves.

Introduction

Patients under the age of 50 who undergo a total hip arthroplasty (THA) are at high risk for wear-related complications due to their higher activity level. Previous studies have shown that highly crosslinked polyethylene (HXLPE) is more durable with no evidence of loosening compared to conventional polyethylene due to its improved wear characteristics. Unfortunately, there are few studies with long term follow-up of HXLPE in this patient population. The purpose of this study was to evaluate two questions related to this population of patients undergoing THA. First, what were the clinical outcomes for HXLPE in patients 50 years or younger at an average follow-up of 15 years? Second, was osteolysis observed in any of these hips?

Background

Pseudotumor or high grade ALVAL (aseptic lymphocyte-dominated vasculitis-associated lesion) development around total hip replacements secondary to local metal debris generation – especially in the setting of metal-on-metal bearings – is a well-recognised histopathologic phenomenon. Recent work has suggested a strong genetic correlation with an individual's risk of such lesion development following metal exposure. Emerging data have highlighted a similar potential concern around total knee replacements (TKRs), particularly with increasing construct modularity. To date, the body-of-knowledge pertaining to TKR-associated ALVALs has largely been limited to individual case reports or small retrospective case series’, with no large-scale investigation looking at this potential complication. This study sought to establish the preliminary prevalence of pseudotumor or high grade ALVAL formation seen at the revision of primary TKRs and to establish the correlation between histologic ALVAL grade and patient-reported functional outcomes.

Gap balancing technique aims to achieve equal and symmetric gap at full extension and in flexion; however, little is known about the connection between the native and the replaced knee gaps. In this study, a novel robotic assisted ligament tensioning tool was used to measure the pre- and post- operative gaps to better understand their relationship when aiming for balance gaps in flexion and extension. The accuracy of a prediction algorithm for the post-operative gaps based on the native gap and implant alignment was evaluated in this study. The medial and lateral gap were smallest at full extension. The native gaps increase with flexion until 30 degrees where they plateaued for the remaining flexion range. The native lateral gap was larger than the medial gap throughout the flexion range. Planning for equal gaps at extension and flexion resulted with tightest gaps at these angle; however, the gaps in mid-flexion were 3–4 mm larger. Good agreement was observed between the post-operative results and the predicted gas from the software algorithm. The results showed that the native gaps are neither symmetric nor equal. In addition, aiming for equal gaps reduces the variation at these angles but could result in mid- flexion laxity. Advanced robotics-assisted instrumentation can aid in evaluation of soft-tissue and help in surgical planning of TKA. This allows the surgeon to achieve the targeted outcome as well as record the final implant tension to correlate with clinical outcomes.

As a treatment for end-stage elbow joint arthritis, total elbow replacement (TER) results in joint motions similar to the intact joint; however, bearing wear, excessive deformations and/or early fracture may necessitate early revision of failed implant components. Compared to hips, knees and shoulders, very little research has been focused on the evaluation of the outcomes of TER, possible failure mechanisms and the development of optimal designs. The current study aims to develop computational models of TER implants in order to analyze implant behaviour; considering contact stresses, plastic deformations and damage progression.

A geometrical model of a TER assembly was developed based on measurements from a Coonrad-Morrey TER implant (Zimmer, Inc., Warsaw, IN). Ultra high molecular weight polyethylene (UHMWPE) nonlinear elasto-plastic material properties were assigned to the humeral and ulnar bushings. A frictional penalty contact formulation with a coefficient of friction of 0.04 was defined between all of the surfaces of the model to take into account every possible interaction between different implant components in vivo. The loading scenario applied to the model includes a flexion-extension motion, a joint force reaction with variable magnitude and direction and a time varying varus-valgus (VV) moment with a maximum magnitude of 13 N.m, simulating a chair-rise scenario as an extreme loading condition. An explicit dynamic finite element solver was used (ABAQUS Explicit, Dassault Systèmes, Vélizy-Villacoublay, France), due to improved capabilities when performing large deformation analyses. Model results were compared directly with corresponding experimental data. Experimental wear tests were performed on the abovementioned implants using a VIVO (AMTI, Watertown, MA) six degree-of-freedom (6-DOF) joint motion simulator apparatus. The worn TER bushings were scanned after the test using micro computed tomography (µCT) imaging techniques, and reconstructed as 3D models. Comparisons were made based on the sites of damage and deformed geometries between the numerical results and experimental test data. In addition to that, parametric geometrical models were developed using worn geometry of the retrievals in order to account for primary wear and deformations while simulating long-term contact stress and secondary damage progression on the bushings (Fig. 1).

Contact pressure distributions on the humeral and ulnar bushings correlate with the sites of damage as represented by the µCT data and gross observation of clinical retrievals. Furthermore, deformation patterns and kinematics of the components are in good agreement with the experimental results (Fig.2). Excessive plastic deformations are evident in both the numerical and the experimental results close to the regions with high contact pressures. Simulating parametric initially-worn geometries results in the formation of secondary damage zones, as well as redistribution of contact stresses and contact locations (Fig. 3).

The results demonstrate UHMWPE bushing damage due to different loading protocols. Numerical results demonstrate strong agreement with experimental data based on the location of deformation and creep on bushings and exhibit promising capabilities for predicting the damage and failure mechanisms of TER implants.

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Patients with osteoarthritis (OA) of the knee commonly alter their movement to compensate for deficiencies. This study presents a new numerical procedure for classifying sit-to-walk (STW) movement strategies.

Ten control and twelve OA participants performed the STW task in a motion capture laboratory. A full body biomechanical model was used. Participants were instructed to sit in a comfortable self-selected position on a stool height adjusted to 100% of their knee height and then stand and pick up an object from a table in front of them. Three matrices were constructed defining the progression of the torso, feet and hands in the sagittal plane along with a fourth expressing the location of the hands relative to the knees. Hierarchical clustering (HC) was used to identify different strategies. Trials were also classified as to whether the left (L) and right (R) extremities used a matching strategy (bilateral) or not (asymmetrical). Fisher's exact test was used to compare this between groups.

Clustering of the torso matrix dichotomised the trials in two major clusters; subjects leaning forward (LF) or not. The feet and hands matrices revealed sliding the foot backward (FB) and moving an arm forward (AF) strategies respectively. Trials not belonging in the AF cluster were submitted to the last HC of the fourth matrix exposing three additional strategies, the arm pushing through chair (PC), arm pushing through knee (PK) and arm not used (NA). The control participants used the LF+FBR+PK combination most frequently whereas the OA participants used the AFR+PCL. OA patients used significantly more asymmetrical arm strategies, p=0.034.

The results demonstrated that control and OA participants favour different STW strategies. The OA patients asymmetrical arm behaviour possibly indicates compensating for weakness of the affected leg. These strategy definitions may be useful to assess post-operative outcomes and rehabilitation progress.

Objectives

Sagittal alignment of the lumbosacral spine, and specifically pelvic incidence (PI), has been implicated in the development of spine pathology, but generally ignored with regards to diseases of the hip. We aimed to determine if increased PI is correlated with higher rates of hip osteoarthritis (HOA). The effect of PI on the development of knee osteoarthritis (KOA) was used as a negative control.

Objectives

The aim of this study was to examine whether asymmetric loading influences macrophage elastase (MMP12) expression in different parts of a rat tail intervertebral disc and growth plate and if MMP12 expression is correlated with the severity of the deformity.

Purpose

Dislocation after revision total hip is a common complication. The purpose of this study was to assess whether a large femoral head (36/40mm) would result in a decreased dislocation rate compared to a standard head (32mm).

Purpose

There is a postulated association between increased serum metal ions and pseudotumour formation in patients with metal-on-metal hip replacements. The primary aim of this study was to assess the prevalence of pseudotumour in 31 asymptomatic patients with a large femoral head (LFH) metal-on-metal hip implant. This was compared to the prevalence of pseudotumour in 20 matched asymptomatic patients with a hip resurfacing (HRA) and 24 matched asymptomatic patients with a standard metal-on-polyethylene (MOP) total hip. A secondary objective was to assess possible correlation between increased serum metal ions and pseudotumour formation

Purpose

Electrothermal arthroscopic capsulorrhaphy (ETAC) was a technology introduced for orthopaedic surgery without good scientific clinical evidence supporting its use. This multicentre randomized clinical trial provides the scientific clinical evidence comparing ETAC to Open Inferior Capsular Shift (ICS), by measuring disease-specific quality of life at 2-years post-operatively, in patients with shoulder instability due to capsular redundancy.

Purpose

This prospective, expertise-based randomized clinical trial compares arthroscopic to open shoulder stabilization by measuring the disease-specific quality of life outcome in patients with traumatic unidirectional anterior shoulder instability, and determining the incidence of recurrent instability at 2-years post-operatively.

Purpose

The outcome following isolated liner exchange for revision knee arthroplasty, while an attractive option for its simplicity, has a mixed outcome reported in the literature. We report our experience in patients who had a minimum of two years follow-up.

Purpose

The purpose of this study was to compare and evaluate the cost-effectiveness of the MIS Anterolateral Approach to that of the MIS Posterolateral and MIS Direct Lateral Approach.

Introduction

Bearing surfaces used for total hip arthroplasty must have characteristics including bio-compatibility, low friction and low wear rate. Bearing combinations are generally characterised as Soft on Hard/Hard. In general, all newer bearing combinations have reduced wear but may present with other issues that impact on patient outcomes.

Introduction

Bone morphogenetic proteins (BMPs) are members of the TGF-beta superfamily of growth factors and are known to regulate proliferation and expression of the differentiated phenotype of chondrocytes, osteoblasts, and osteoclasts. To investigate the osteoblastic differentiation gene expressions that contribute to BMP-7 dependent ostogenesis, we performed gene expression profiling of BMP-7-treated mouse bone marrow stromal cells.

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.

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.

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.

Purpose: This prospective, randomized double-blinded clinical trial compared cemented fixation of the humeral component to uncemented/tissue-in-growth fixation in total shoulder arthroplasty for primary osteoarthritis of the shoulder.

Method: All patients presenting with primary osteoarthritis of the shoulder requiring replacement were screened for eligibility. Patients were randomized in the operating room after glenoid preparation to the cemented or uncemented group by a computer-generated, stratified randomization procedure. Outcome measures included disease specific QOL assessment (WOOS), SF-12, ASES, MACTAR, radiographic evaluation of component fixation, operative time, complications and revision surgery. Patients were assessed by a blinded evaluator in post-operative intervals of 2 and 6 weeks, and 3, 6, 12, 18, and 24 months. The primary endpoint was the WOOS score at 2 years.

Results: One hundred and sixty-one patients were consented and randomized for the study. There were 80 patients in the cemented and 81 patients in the uncemented group. At baseline, the groups were alike with regards to demographics and baseline evaluations. The WOOS scores at post-operative intervals of 12, 18 and 24 months showed a significant difference (p=0.009, 0.001, 0.028 respectively) in favour of the cemented group. The cemented group also had better strength (3 m p=0.038, 12 m p= 0.036, 18 m p=0.051, 24 m p=0.053) and forward flexion (6m p=0.031, 12 m p=0.04). As expected, the operative time was significantly less for the uncemented group (C = 2.26h +/−.63; U = 1.69h +/− 1.9, p= 0.03).

Conclusion: These findings provide the first evidence that cemented fixation of the humeral head provides better quality of life, strength and ROM than uncemented fixation. This was a Tier 1 Project of the JOINTs Canada group.

Purpose: Shoulder instability is a common problem affecting patients in their most active years resulting in an impact on their quality of life. The WOSI is a validated, disease-specific (shoulder instability) evaluative quality of life measure. It has not been tested for its ability to discriminate between those who require surgical care and those who do not. The purpose of this study is to determine if the WOSI can discriminate between surgical and non-surgical patients and between patients with different types of shoulder instability.

Method: Sixty patients with a confirmed diagnosis of shoulder instability were included as cases. Twenty had documented multidirectional instability requiring surgery: Group 1 Surgical MDI – 20 patients had documented recurrent traumatic anterior dislocations requiring surgery: Group 2 Surgical Anterior – 20 patients were first time anterior dislocators who were followed for a minimum one year who had no further recurrences and did not require surgery: Group 3 Non-Surgical First Time Anterior – The cases were compared to 60 age and gender matched control patients with no history of shoulder problems: Group 4 Control – WOSI scores were analyzed using a one-way ANOVA.

Results: The WOSI scores were as follows: Group 1 Surgical MDI- mean 30.5 (95% CI 23.1–37.8); Group 2 Surgical Anterior- mean 39.8 (95% CI 33.1–46.5); Group 3 Non-Surgical First time Anterior- mean 76.2 (95% CI 66.4–86.0) and Group 4 Control- mean 96.6 (95% CI 95.8–97.4). Based on the 95% Confidence Intervals, there were statistically significant differences between the two surgical groups (Group 1 Surgical MDI and Group 2 Surgical Anterior) compared to the non-surgical patients (Group 3 Non Surgical First Time Anterior) and the controls (P=0.000). There is a trend to discriminate between the two surgical groups (P=0.079).

Conclusion: The WOSI Index clearly discriminates between surgical and non-surgical patients with shoulder instability, and the control population with normal shoulders. There is a trend to discriminate between MDI and recurrent anterior traumatic dislocators.

The non-operative treatment of idiopathic clubfoot has become increasingly accepted worldwide as the initial standard of care. The Ponseti method has become particularly popular as a result of published short and long-term success rates in North America. Non-compliance with abduction bracing has been proven to be a major risk factor for recurrence of clubfoot. The purpose of this retrospective study was to identify those patients who were non-compliant with the abduction bracing post casting and to then assess the rate and severity of recurrence.

One-hundred and fifty children (184 feet) with unilateral or bilateral clubfoot who were treated with the Ponseti method by the senior author from 1999 to 2008 were reviewed. We identified those patients who were non-compliant with the abduction bracing. Compliance was defined as three months full time wear followed by twelve months night-time/nap-time wear. Recurrence was classified as minor, defined as those requiring an extra-articular surgical procedure and major, requiring an intra-articular procedure.

We identified fifty children with seventy clubfeet who were followed up for a minimum of 12 months. None of these patients were compliant with brace wearing. Of the 70 feet, 40 (57%) required surgical intervention. There were 30 (43%) feet with no clinical recurrence. In 5 of the bilateral cases only one of the feet had required corrective surgery. In the 29 patients who required surgical intervention we identified 52 procedures (37 extra-articular and 15 intra-articular).

Compliance with the post correction abduction bracing protocol is crucial to avoid recurrence of a clubfoot deformity treated with the Ponseti method. Despite non-compliance however there is a significant proportion of patients who do not require any surgical intervention. We recommend initiating the Ponseti technique on all patients with clubfeet rather than being selective due to anticipated compliance issues with the family.

UK military forces have been deployed in Afghanistan since 2006 as part of the International Stabilisation Assistance Force. The Operation is supported by a 50-bedded hospital. In 2007 the Defence Medical Services introduced a massive haemorrhage policy. In asymmetric warfare gunshot wounds (GSW), improvised explosive devices (IED) and mine injuries are prevalent and we hypothesized that they would require significant blood products.

We prospectively collected data from consecutive trauma resuscitations over 3 months (January to March 2008). Pre-hospital time points, mechanism of injury, injury distribution, injury severity score (ISS), new injury severity score (NISS), surgical procedures, blood product utilisation and outcome were recorded.

115 trauma resuscitations were performed over the study period. Median pre-hospital time was 95 minutes (range 30–325), with median 64 minutes to the arrival of the Medical Emergency Response Team helicopter. The cause of injury was landmine (20), IED (31) and GSW (40); mean number of involved body systems was 1.4, 1.8 and 1.5 respectively and injured structures 2.8, 3.5 and 2.3 respectively (IED> GSW p< 0.05). Mean ISS was 16, 16.8, 14.9 and NISS 18.7, 20.9, and 17.9 respectively. Blood transfusion was required in 3 mine, 14 IED and 17 GSW casualties (mine< IED & GSW, p< 0.05) with 10.6, 11.4, and 13.9 units of blood transfused per casualty.

Injury severity for casualties is high with multiple injuries to body systems irrespective of mechanism. Anti-personnel mine injuries were significantly less likely to require transfusion. Large quantities of blood products were still required when necessary in all mechanisms of trauma. It is therefore recommended that during the pre-hospital time the major transfusion protocol should be placed on stand-by.

Purpose: Use of six-axis analysis and computer assisted deformity correction via a circular external fixator is a new method for deformity correction. We investigated its accuracy and safety in reconstruction of femoral deformity in children and young adults.

Method: We retrospectively reviewed all cases including the indications for use and the methodology of application of the computer assisted six-axis analysis and circular external fixator for reconstruction of 22 femora in 20 patients. Twelve patients were female, and 8 were male. The average age was 13.9 (range, 5.9–24.6). Etiology included traumatic (7), idiopathic (6), multiple enchondromatosis (2), rickets (2), congenital femoral deficiency (2), spondyloepiphyseal dysplasia (1), congenital pseudohypoparathyroidisim (1), and multifocal osteomyelitis (1). Clinical and radiographic data were analyzed.

Results: Average follow-up was 14.4 months (range, 4.5–32). Average time in frame was 6.2 months (range, 2.6–19). Bone lengthening of 3.9 cm (range, 1–8.5) was performed in 12 femora. In genu valgum patients, the mLDFA improved from a mean of 73.7° to a mean of 89°. In genu varum patients, the mLDFA improved from a mean of 99.8° to a mean of 89.5°. Complications included pin tract infection in 6, knee stiffness in 3, delayed union in 2, skin irritation in 1, posterior knee subluxation in 2, both of which had stable knees preoperatively. One patient was lost to follow-up and returned back with deformity. No complications occurred in 8 patients.

Conclusion: Computer assisted femoral deformity correction with six-axis analysis and application of circular external fixator is a useful technique with the advantage of managing multiplanar deformities in children and young adults. It has the potential complications of the use of any external fixator. Close follow-up is necessary to avoid subluxation of the knee joint even in patients with stable knees. Accurate and safe correction can be achieved in almost all patients.

We suggested a new concept of buffered implant fixation. It is a cementless fixation using a buffer instead of the cement between the bone and the implant. We investigated the feasibility of the buffered implant fixation using a rat model. In our previous study, we measured the amount of bone around the implant to compare the buffered implant fixation with the cemented fixation. The results showed the difference in change of Bone Volume/Total Volume (BV/TV) with time between the buffered fixation and the cemented fixation. Now, in this study, we are comparing the mechanical interface strength between two fixations.

After micro CT scanning, the specimens were used for mechanical push-out test to measure the interface shear strength at the buffer-bone or cement-bone interface. The distal side of the femur was carefully removed to expose the whole distal region of the implant while the proximal side of femur was cut carefully with diamond saw (Metsaw, R& B Inc., Korea) until the proximal end of cement or buffer is exposed. The femur was embedded into a push-out jig with a plaster. The push-out jig was mounted in a material testing machine (KSU-10M, Kyungsung testing machine, Korea) and loaded at a rate of 0.01mm/s. The apparent interface strength was calculated by dividing the peak force by the surface area of the buffer or cement.

After 2 weeks, the apparent interface strength is 217.0 ± 280.0(average ± standard deviation) for buffer and 472.4 ± 381.1 for cement; after 4 weeks, 92.9 ± 67.6 and 268.1 ± 197.9; after 12 weeks, 441.9 ± 467.1 and 201.8 ± 132.3, respectively. The buffered fixation showed gain in strength with time while the cemented fixation showed reverse tendency but the interaction by ANOVA was not significant (p=0.125). Even though the excellence of buffer fixation was not clearly confirmed because of small sample size and high variance, the feasibility of the buffer fixation was shown.

However, further studies are necessary to improve the buffered implant fixation. To enhance the cell adhesion and biocompatibility, it is necessary to modify the surface of polyetheretherketone (PEEK) such as by plasma treatment or biological coating. Also, an animal test using a higher level animal such as dog or pig is necessary.

Purpose: Waterproof casts have been shown to be a safe and effective means of immobilization in children with minimally displaced fractures. The purpose of this study was to determine if waterproof Gore-Tex-lined casts are as effective as traditional cotton-lined casts in the immediate postoperative period after closed reduction of displaced distal radius fractures in children.

Method: We performed a retrospective review of distal radius fractures that underwent closed reduction and application of a long-arm cast between June 2004 and December 2006. A total of 124 cases were included (55 Gore-Tex; 69 traditional cotton-lined). The primary outcome measure was redisplacement in the cast. The cast index was also used to assess the quality of cast molding. Data was analyzed using repeated measures ANOVA. Power analyses were also conducted.

Results: There were no significant differences between the two groups with regards to translation of the radius or angulation of the radius on anterior-posterior (AP) and lateral radiographs at the time of injury, postreduction, or cast removal. Redisplacement as measured by the change in translation of the radius and angulation of the radius on AP and lateral radiographs from the time of reduction to cast removal was also not significantly different between the two groups. The mean cast index for the Gore-Tex and traditional cotton-lined groups was 0.882 and 0.873 respectively, which was not a significant difference.

Conclusion: A waterproof Gore-Tex-lined cast will maintain fracture reduction as well as a cotton-lined cast for closed reductions of distal radius fractures in children in the immediate postreduction period. Waterproof casts also provide extensive benefits to the patient with regards to bathing, hygiene, and participation in aquatic activities

Spontaneous osteonecrosis of the knee (SPONK) usually involves a single condyle or plateau. The medial femoral condyle is most often involved and spontaneous osteonecrosis of medial tibial plateau is a rare condition, representing only 2 % of all necrosis reported in the knee. Therefore, SPONK with both involvement of medial femoral condyle(MFC) and medial tibial plateau(MTP) might be extremely rare. SPONK in each MFC or MTP respectively might be extended into corresponding side of the knee at their advanced final stage, howevere, in that situations, significant degenerative change would accompany and it might be difficult to differentiate final staged SPONK form severe osteoarthritis. To the best of our knowledge, SPONK affecting both medial femoral condyle and medial tibial plateau without significant secondary osteoarthritis changes is not reported, even though it was difficult to know which occurred first. We experienced 3 patients with histologically proven osteonecrosis of the medial tibial condyle and medial tibial plateau, and report their radiologic features. All 3 patients showed similar ridiograhic patterns. Medial portion of medial tibial plateau and lateral portion of medial femoral condyle showed longitudinal fracture like-subchondral collapse. Standing anteroposterior radiograph at 30 degree knee flexion showed well fitted features such as “locked” medial condyle. Varus angulation was present. Significant degenerative changes was not shown except for subchondral sclerosis. T1-weighted coronal and Fat suppressed T2-weighted MR images showed subchondral collapse with ill-defined diffuse bone marrow edema changes on both tibial and femoral condyles. At surgical findings, longitudinal track-like groove was shown in both medial femoral condyle and medial tibial plateau. Articular cartilage was denuded and showed glistening surface with bone defect of lateral side of medial femoral condyle and medial side of tibial articular surface. Histological analysis shows necrotic bone, surrounded by an area of fibrovascular granulation tissue on both femoral and tibial sides. Total knee arthoplasty was performed in all 3 patients. As a result of very low prevalence of both involvement of MFC and MTP and limited number of our cases, we could not conclude that radiologic features in our cases are typical radiologic pattern of both involvement. However, based on our cases, we believe that this characteristic radiologic features may considered as one of the possible various radiologic findings of simultaneous involvement in MFC and MTP and allow diagnosis for SPONK with both involvement in MFC and MTP to be facilitated.

Purpose: Porous tantalum has been shown to be very effective in achieving bone ingrowth. However, in some circumstances, bone quality or quantity is insufficient to allow adequate bone ingrowth. We hypothesized that the addition of alendronate to porous tantalum would enhance the ability of porous tantalum to achieve bone ingrowth in these challenging situations, such as when a gap exists between the implant and bone. We evaluated the effect of alendronate coated porous tantalum on new bone formation in an animal model incorporating a gap between implant and bone.

Method: Thirty-six cylindrical porous tantalum implants were bilaterally implanted into the distal femur of 18 rabbits for 4 weeks. There were 3 groups of implants inserted; a control group of porous tantalum with no coatings, porous tantalum with micro-porous calcium phosphate coating, and porous tantalum coated with micro-porous calcium phosphate and alendronate. Subcutaneous fluorescent labeling was used to track new bone formation. Bone formation was analyzed by backscattered electron microscopy and fluorescent microscopy on undecalcified samples.

Results: The relative increase in mean volume of gap filling, bone ingrowth and total bone formation was 143% (p< 0.001), 259% (p< 0.001) and 193% (p< 0.001) respectively in the alendronate coated porous tantalum compared with the uncoated porous tantalum controls. The relative increase in the percentage of new bone-implant contact length was increased by 804% on average in the alendronate coated porous tantalum compared with the uncoated tantalum controls.

Conclusion: This study demonstrated the significant enhancement of bone-implant gap filling and bone ingrowth which can be achieved by coating porous tantalum with alendronate. It is proposed that, when faced with the clinical problem of revision joint replacement in the face of bone loss (at the hip, knee or elsewhere), the addition of an alendronate-delivery surface coating would enhance biological fixation of the implant and promote the healing of bone defects.

The anterior pelvic plane has been introduced as a concept of the reference plane to image free navigation-assisted cup placement of total hip arthroplasty. With the neutral pelvis, the anteversion relative to the conventional coordinate system is equal to the that of relation to the anatomical coordinate system. This is the rationale of image free navigation system. But, currently, two major concerns about image-free navigation assisted total hip arthroplasty are tilting of anatomic coordinate system and the cutaneous palpation procedure. Therefore, it was the goal of this study to provide both the bone anterior pelvic plane (Bone_APP) and the overlying soft tissue plane (Soft_APP) simultaneously, and to find possible correlations of biometrical parameters and effect of ante-version were an additional motivation of this study. 23 Korean adult patients underwent image-free navigation-assisted total hip arthroplasty. The tilting of Bone_APP, soft tissue thickness on ASIS, pubis, and then tilting of Soft_APP, and anteversion of cup were measured with reconstructed CT and 3D workstation system.

The average age was 66.1 years, the average height was 162.5cm at a weight of 59.2 kg. The average body mass index was 22.3. And the average lumbar lordosis was measured as 30.4 degrees. The soft tissue on the level of the pubis was 17.6 mm thicker than that on the level of ASIS in average. In all cases, Soft_APP was positive, that is from 3.5 to 16.5 degrees of backward rotation. We also found a high-intersubject variability in the Bone_APP from 13.4 of forward rotatation to 23 degrees of backward rotation. Overall, there are no correlation between biometrical parameters and difference of navigated data to others measured on CT. Averaged navigated data was 22.4 degrees. The average anatomic, operative, and planar anteversion were 29.2, 27.2 and 21.3 degrees respectively. The value of anteversion measured on the transverse plane and sagittal plane shows higher than navigated anteversion in paired comparison. This could be comprehended that the navigation system had under-estimated the anteversion than that of transverse and sagittal plane, This means navigation assessed pelvic plane as back ward tilting rather than forward tilting intraoperatively.

None of cases showed the Bone_APP was parallel to conventional coordinate system. Comparing the variable bone APP tilt, all of cases showed an backward tilted soft tissue plane. There were no correlation between bone APP and biometrical parameters. Overall, navigated data were less than anatomic and operative anteversion. Rather than anatomic coordinate system (Bone-APP), backward tilting due to overlying soft tissue (Soft-APP) might to make the navigated data have the tendency to under-estimated the anteversion of cup measured with CT. In conclusion, anterior pelvic plane does not satisfactory reliability with should be easily identified during operation. Image-free navigation system would take into account variations of individuals including both bone tilt and soft tissue plane.

The cemented and cementless implant fixations are popular in orthopaedic arthroplasty. However, these implant fixations have some problems such as cement failure, wear debris, stress shielding, revision and so on. To overcome these problems, we are developing a new concept of buffered implant fixation which uses a bone-friendly buffer between the implant and the bone. In this study, we performed a finite element analysis to evaluate the buffered implant fixation in comparison with cemented and cementless implant fixations in mechanical aspects. In addition, we investigated the effect of buffer taper angle to the stress distribution in the buffered implant fixation.

Three-dimensional FEA of the cemented, cementless and buffered fixation were performed using the ABAQUS program. In these FEA, the ‘standardized femur’, which is the composite femur model supplied by Pacific Research Lab., was used as the bone model and the CPT stem and the Versys Fibermetal Midcoat stem were modeled for the cemented fixation and the cementless fixation, respectively. These three-dimensional models were meshed using the tetrahedral elements with 4 nodes (C3D4) and the additional contact definitions. The buffered implant fixation is similar with the polished cemented fixation except the material between the implant and the bone. The polyetheretherketone (PEEK) was selected as the buffer material. Also, several taper angles of buffer were simulated to change the stress distributions in the buffered fixation. The external load three times of mean body weight (74.3 kg) was cyclically loaded at the femoral head with the angle of 20° in adduction and 6° in flexion while the distal end of femur was fixed.

In the buffered implant fixation, the taper-locked effects were observed. The buffered fixation had greater cyclic compression for the bone compared to the cemented fixation. Also, the failure probability of the buffer in the buffered fixation was less than that of the cement in the cemented fixation. The risk factors in the buffer were 0.148 for the tension and 0.176 for the compression while, the risk factors of cement in the polished cemented implant fixation were over than 1. Moreover, the buffered fixation had widely distributed compression compared to the cementless fixation and the stress distribution could be modified easily to change the taper angle of buffer. The FEA results showed that the buffered implant fixation would provide an appropriate mechanical environment.

Introduction and Objectives: We analyzed the physical and health status of patients with ankle arthritis that underwent arthrodesis or total ankle replacement and determined which alternative provided a greater perception of improvement in quality of life and whether there was any difference in the perception of the patients that underwent either of these two procedures.

Materials and Methods: This is a comparative-prospective study in patients that underwent arthrodesis (16 cases) or total ankle replacement (14 cases) in which clinical-functional variables were assessed by means of the AOFAS score and quality of life was measured using SF-36 at 2 years of follow-up and this was compared with preoperative assessment.

Results: The study was carried out with 2 series of comparable patients, both surgical techniques showed a statistically significant improvement on clinical assessment and on quality of life assessment in comparison with preoperative status after 2 years of follow-up. The group of patients that underwent arthrodesis changed from mid-range AOFAS values of 37.12 to 45.62 (p=0.055) and mid-range SF-36 values of 32.96 to 46.25 (p=0.008). The group that underwent arthroplasties changed from mid-range AOFAS values of 33 to 62 (p=0.024) and mid-range SF-36 values of 33.62 to 59.84 (p=0.001). The improvement was statistically greater in the group that underwent arthroplasties than in the group that underwent arthrodesis (p=0.48 for AOFAS, and p=0.026 for SF-36)

Discussion and Conclusions: Both procedures are good treatment options, they ‘significantly improve patient’s status both clinically and in their perception of their health and quality of life. The medium term perception of quality of life and general health on the part of patients with ankle arthritis is better when they undergo ankle arthroplasty than when they undergo surgical fusion.

There is an ever-increasing clinical need for the regeneration and replacement of tissue to replace soft tissue lost due to trauma, disease and cosmetic surgery. A potential alternative to the current treatment modalities is the use of tissue engineering applications using mesenchymal stem cells that have been identified in many tissue including the infrapatellar fat pad. In this study, stem cells isolated from the infrapatellar fat pad were characterised to ascertain their origin, and allowed to undergo adipogenic differentiation to confirm multilineage differentiation potential.

The infrapatellar fat pad was obtained from total knee replacement for osteoarthritis. Cells were isolated and expanded in monolayer culture. Cells at passage 2 stained strongly for CD13, CD29, CD44, CD90 and CD105 (mesenchymal stem cell markers). The cells stained poorly for LNGFR and STRO1 (markers for freshly isolated bone marrow derived stem cells), and sparsely for 3G5 (pericyte marker). Staining for CD34 (haematopoetic marker) and CD56 (neural and myogenic lineage marker) was negative.

For adipogenic differentiation, cells were cultured in adipogenic inducing medium consisting of basic medium with 10ug/ml insulin, 1uM dexamthasone, 100uM indomethacin and 500uM 3-isobutyl-1-methyl xanthine. By day 16, many cells had lipid vacuoles occupying most of the cytoplasm. On gene expression analyses, the cells cultured under adipogenic conditions had almost a 1,000 fold increase in expression of peroxisome proliferator-activated receptor gamma-2 (PPAR gamma-2) and 1,000,000 fold increase in expression of lipoprotein lipase (LPL). Oil red O staining confirmed the adipogenic nature of the observed vacuoles and showed failure of staining in control cells.

Our results show that the human infrapatellar fat pad is a viable potential autogeneic source for mesenchymal stem cells capable of adipogenic differentiation as well as previously documented ostegenic and chondrogenic differentiation. This cell source has potential use in tissue engineering applications.

Purpose of Study: We aimed to reduce the work intensity involved in auditing high volume procedures (eg knee arthroscopy) by developing and validating a tool which uses routinely acquired hospital data, to target those patients most likely to have developed an undesirable post-operative outcome.

Methodology: The work was a collaboration effort between the Orthopaedic and Clinical Effectiveness departments. During the period 1997–2003, 2926 elective knee arthroscopies were identified as having been performed in our unit. Linkage of routinely collected data held on the hospital’s computerized Patient Administrative System (PAS), hospital theatre system and A& E system, with data from the Office of National Statistics concerning death, high-lighted 183 cases (Core group) meeting one or more of four indicators: readmission < 28 days, return to theatre < 28 days, return to A& E < 28 days, and length of stay 4+ days (Graph 1). The accuracy of the tool to identify undesirable post-operative outcomes was made comparing the Core group and a Random sample (N=240).

Results: Accuracy of OPCS-4 coding for arthroscopic procedure performed was 77.1% in the core group and 96.4% in the random sample. The new tool yielded a sensitivity of 38% and specificity of 95%. Where major complications were concerned the sensitivity rose to 100%. For major complications the proposed model indicated a 0.6% complication rate vs 0.5% actual rate. For minor complications the proposed model indicated a 1.4% rate vs 3.8% actual rate. Overall complication rate within our unit was comparable to the published literature.

Conclusion: The tool has achieved its aim of identifying all major complications and undesirable events, along with many minor complications. As the tool identifies additional information it must be used as an aid to identifying patients for case note review. However, in our study it reduced the number needed to less than 7% of the total.

Rotator cuff tears are a common cause of shoulder pain and dysfunction. Therefore, the purpose of this in-vitro biomechanical study was conducted to determine the effects of simulated tears and subsequent repairs of the rotator cuff tendons on joint kinematics.

Eight paired fresh-frozen cadaveric shoulder specimens (mean age: 66.0 ± 8.7 years) were tested using a custom loading apparatus designed to simulate unconstrained motion of the humerus. Cables were sutured to the rotator cuff tendons and the deltoid. Loads were applied to the cables based on variable ratios of electromyographic (EMG) data and average physiological cross-sectional area (pCSA) of the muscles. An electromagnetic tracking device (Flock of Birds, Ascension Technologies, VT) was used to provide real-time feedback of abduction angle, to which the loading ratio was varied correspondingly. 2 and 4cm tears were made starting at the rotator cuff interval and extending posteriorly. Specimens were randomised to receive either single or double suture anchor repair. In order to quantify repeatability, five successive tests on each of the intact, torn, and repaired cases were performed. Statistical significance was established using One- and Two-way Repeated Measured ANOVAs (p< 0.05).

Rotator cuff tears caused alteration in glenohumeral kinematics. A 2cm tear caused the humerus to consistently move posterior through the arc of abduction; however, as the tear increased to 4cm the humerus moved anteriorly, returning towards the intact state. Double row suture anchor repairs more accurately reproduced the kinematics of the intact specimen compared to single row suture anchor repair.

The initial posterior displacement in the plane of elevation with the sectioning of the supraspinatus is related to the diminished anterior moment on the glenohumeral joint. As the tear proceeds into the infraspinatus, the anterior and posterior forces become more balanced and a return to near normal intact kinematics was observed. This study demonstrates that double row suture anchor repair more accurately reproduces active shoulder kinematics of the intact shoulder specimens.

Purpose: To investigate the potential value of titanium anterior interbody cages compared to morselized rib graft for anterior interbody fusion in combination with posterior instrumentation, correction and fusion for Scheuermann’s kyphosis.

Methods and Materials: A Non-Randomised historic cohort study of two surgical techniques in matched subjects was carried out.15 patients with identical pre-operative radiographic and physical variables (age, gender, height, weight, BMI ) were managed with combined anterior release, interbody fusion, posterior instrumentation, correction and fusion . Group A (n=8) had morsilized rib graft inserted into each intervertebral disc space. Group B (n=7) had titanium interbody cages packed with bone graft inserted at each level. The posterior instrumentation extended from T2 to L2 in both groups. Pre- and post-operative curve morphometry was studied on plain radiographs by two independent observers. The indices studied included Cobb angle, Ferguson’s angle(FA) , Voutsinas index(VI), Sagittal Vertical Axis (SVA), Sacral Inclination (SI) and Lumbar Lordosis (LL). Interbody Fusion was assessed at final follow up. Each patient was reviewed at 3, 6, 12, 24, 48 and 60 months following surgery with standing radiographs. Wilcoxon-matched pairs test and Mann-Whit-ney test were used for statistical analysis.

Results: The average follow-up for groups A was 70 and Group B,66 months. For the whole group, the pre-operative : postoperative median Cobb angle, FA, VI, SVA and SI were 86: 42degrees, 50 : 28.4degrees, 28.7 :13, −3.5 : −4.0 centimetres and 40 : 34 degrees respectively. There were significant differences for all variables [p< 0.01] indicating good correction. At four-year follow-up, fusion criteria were satisfied in 12 / 15 cases (80%). Three patients had distal junctional kyphosis. There was no significant difference with respect to the variables between the two groups and both retained the post-operative correction achieved.

Conclusion: There was no significant advantage in the use of anterior titanium interbody cages over the use of morselized rib graft in the surgical management of Scheuermann’s Kyphosis.

Purpose: To identify patients in whom anterior scoliosis correction was not possible and to determine pre-operative factors that may predict such an outcome.

Methods: From 1999–2005, 257 patients were listed for anterior correction with the Kaneda Anterior Spine System (KASS). Of these 246 were completed successfully. However in 11 cases it was not possible to complete the procedure.

We performed a retrospective review of case notes and X-rays. A control group of 22 patients, in whom anterior surgery was completed, matched to age, sex and type of curve, was used.

Results: Two reasons for abandoning anterior instrumentation were identified; loss of cord signal (7) and failure to achieve adequate correction after anterior release and reduction (4).

Of the seven patients with lost signal three were syndromic and four were associated with syrinx. In all seven, loss of signal occurred on clamping of segmental vessels. All seven had no residual neurological deficit post-operatively and had uncomplicated posterior correction the following week.

All four patients in whom inadequate correction was achieved after anterior release and repositioning had idiopathic curves. Of these two were thoracic and two were thoracolumbar. Mean pre-operative Cobb angle was 67 (range 59–85) compared to a mean of 56 (range 42–68) in the control group. Mean pre-operative stiffness index was 91% (range 85%–100%) compared to a mean stiffness index of 65% (range 53–80) in the control population.

Conclusion: Whilst a successful outcome is achieved in a majority of KASS instrumentations we have identified two reasons why anterior surgery has to be abandoned. Whilst one often cannot pre-operatively anticipate intra-operative loss of cord signal, we found that in cases with an underlying syrinx there is a particular risk of this occurrence. Our experience has shown particularly stiff curves (Stiffness index ≥ 85%) may not be suitable for stand-alone anterior surgery.

Introduction: There has been an increasing use of orthotic knee braces in the management of knee injuries. To ensure the biomechanics of the knee are not adversely affected, it is important that orthotic knee braces accurately provide the desired angle of immobilisation. The objective of our study was to measure the actual knee flexion angles for a lockable orthotic knee brace, and measure the resulting knee flexion moment.

Materials and methods: Eight healthy male volunteers participated in the study looking at six different types of knee immobilisation: locked in 0, 10, 20, 30 degrees of knee flexion, with the brace unlocked, and without a brace. Force and 3-dimensional motion data were collected using a single Kistler force plate and an eight-camera Qualisys ProReflex motion analysis system.

Results: The kinematic knee flexion angles were significantly different when compared with the angles set at the orthotic knee brace for 0 degrees (p=0.001) and 10 degrees (p=0.011). The kinematic knee flexion angle when no brace was used was significantly different from the angle for the unlocked orthotic knee brace (p= 0.003). The knee flexion moment was directly proportional to the knee flexion angle. There was a statistically significant difference between the knee flexion moment for the six types of immobilisation (p< 0.001).

Discussion: The knee flexion angles measured using the kinematic data did not always correspond with the angle set at the orthotic knee brace. These findings highlight inadequacies in the design of lockable orthotic knee braces, especially at low flexion angles of 0 and 10 degrees. The resulting higher actual knee flexion angles were associated with greater knee flexion moments and joint reaction forces at the tibiofemoral and patellofemoral joints. This can, at best result in increased energy expenditure and decreased agility, and at worse potentially augment injuries to the knee.

Introduction: Achieving durable implant–host bone fixation is the major challenge in uncemented revision hip arthroplasty when significant bone stock deficiencies are encountered. The purpose of this study was 1) to develop an experimental model which would simulate the clinical revision hip scenario and 2) determine the effects of alendronate coating on porous tantalum on gap filling and bone ingrowth in the experimental model.

Methods: Thirty-six porous tantalum plugs were implanted into the distal femur, bilaterally of 18 rabbits for four weeks. There were 3 groups of plugs inserted; control groups of porous tantalum plugs (Ta) with no coating, a 2^nd control group of porous tantalum plugs with micro-porous calcium phosphate coating, (Ta-CaP) and porous tantalum plugs coated with alendronate (Ta-CaP-ALN). Subcutaneous fluorochrome labelling was used to track new bone formation. Bone formation was analysed by backscattered electron microscopy and fluorescence microscopy on undecalcified histological sections.

Results: The relative increase in mean volume of gap filling, bone ingrowth and total bone formation was 124 %, 232 % and 170 % respectively in Ta-CaP-ALN compared with the uncoated porous tantalum (Ta) controls, which was statistically significant. The contact length of new bone formation on porous tantalum implants in Ta-CaP-ALN was increased by 700% (8-fold) on average compared with the uncoated porous tantalum (Ta) controls.

Discussion: Alendronate coated porous tantalum significantly modulated implant bioactivity compared with controls. This study has demonstrated the significant enhancement of bone-implant gap filling and bone ingrowth, which can be achieved by coating porous tantalum with alendronate. It is proposed that, when faced with the clinical problem of revision joint replacement in the face of bone loss, the addition of alendronate as a surface coating would enhance biological fixation of the implant and promote the healing of bone defects.

Purpose: To study acute effects of Intradiscal Electrothermal Therapy(IDET) on biomechanical properties of human intervertebral discs using Scanning Acoustic Microscopy(SAM) and 11.6 Tesla Nuclear Magnetic Resonance(μNMR)Microscope.

Materials and Methods: Five SpineCATH® IDET catheters (Smith& Nephew) were sited in the lumbar discs of a fresh frozen human cadaver under image control. 6 regions of interest (ROI) – anterior middle (AM), right anterolateral (RAL), left anterolateral(LAL), posterior middle(PM), right posterolateral (RPL) and left postero-lateral (LPL) were marked. These ROI were then subjected to SAM (50MHz, Kremer GmbH).

SAM was performed in C-scan mode(gate width 50ns, depth 3500ns) and acoustical data collected along X–Y plane/depth Z. A B- mode scan acquired acoustic data along X–Z plane/ depth A. Time-of-Flight (TOF) scan used to create 3D-like images based on distance between the top of the disc and maximum penetration depth.

The IDET catheters were heated according to the 90⁰C 16.5-minute protocol. Discs were subjected to SAM using identical protocols as described. The ROIs were incised and analysed using μNMR. A custom made device was fabricated to prevent rotational effects of varying orientation of the specimen in the magnetic field.

Results: 30 ROI were studied using SAM and μNMR. Acoustic Impedance was significantly decreased (p< 0.01)on SAM and these changes were confined only to LPL and LAL.

Non-linear regression analysis of Signal Intensity Ratios of 30 different regions using SPSS showed a significant change in T1 weighting on μMRI by a median factor of 40 ( IQR + 16) for the LPL and 20(IQR + 8) for LAL regions. Significant relaxation difference (p< 0.001) caused by “magic angle”effects wer noted in LPL compared to RPL.

Conclusion: This is the first study depicting structure of human intervertebral discs using 11.6T μMRI and SAM and exploring its clinical potential. The study irrefutably proves that IDET decreases stiffness coefficient only in the treated area. The findings on SAm closely mimicked findings on μMRI.

Introduction: Deep infection in total hip replacement can be devastating. We report the outcomes 10–15 years after two stage revision for hip infection in 103 patients using the PROSTALAC (prosthesis of antibiotic-loaded acrylic cement) hip.

Methods: All patients or their next of kin were contacted to determine their current functional status and whether they had required repeat surgery or had recurrent infection. The Oxford-12, SF-12, and WOMAC questionnaires were administered. A comprehensive chart review was undertaken to review the infective organisms, surgery, approach, complications, and need for further revision surgery.

Results: 11 patients had re-infection, 7 of whom responded to repeat surgery with no further sequelae. Two patients required resection arthroplasty, one patient underwent hip disarticulation after eventual failure of treatment and bone loss, and one immuno-compromised patient developed osteomyelitis and was subsequently lost to follow-up. Long-term success rate for two stage-revision is thus 89%, or 96% with additional surgery. Since then, 3 patients required revisions for aseptic loosening, 1 for recurrent dislocation. We were able to follow up 45 patients, 75 % of whom provided health-related quality of life outcome scores. 39 patients were deceased, with their outcome confirmed via their last follow-up or with family members, for a total follow-up rate of 85 %. 15 patients were lost to follow-up, but did not undergo further surgery or have reinfections treated at our centre.

Discussion: Two-stage revision for hip infection, which includes an interim prosthesis of antibiotic loaded cement, offers a predictable and lasting solution for patients with this difficult problem.

Introduction: The aims of this study were to

determine predictors of pain, function and activity level 1–2 years after revision hip arthroplasty and

Methods: A prospective cohort of 222 patients who underwent revision hip arthroplasty were evaluated. Predictive models were developed and proportional odds regression analyses were performed to identify factors that predict quality of life outcomes at 1 and 2 years post surgery. The dependent outcome variables were WOMAC function, pain and UCLA activity. The independent variables included patient demographic, surgery specific and objective parameters including baseline Western Ontario McMaster Universities (WOMAC) osteoarthritis index, and the Short Form-12 mental component. The Loess method was used to plot the change of WOMAC and SF-12 scores over time.

Results: There was a significant improvement (p< 0.001) in all patient quality of life scores from baseline with results plateauing at 1 year. UCLA activity remained static between 1 and 2 years. In the predictive model, higher baseline WOMAC function (p < 0.001), age between 60–70 (p< 0.037), male gender (0.017), lower Charnley class (p < 0.001) and diagnosis of aseptic loosening (p < 0.003) were significant predictors of improved function.

When considering WOMAC pain as an outcome variable, factors predictive of improving category outcome included baseline WOMAC function (p= 0.001), age between 60–70 (p< 0.004), male gender (p= 0.005), lower Charnley class (p< 0.001) and no previous revisions (p < 0.023). Baseline WOMAC pain did not predict final pain outcome. Baseline WOMAC function (p=0.001), the indication for the operation (p=0.007), and the operating surgeon were significant predictors of UCLA activity at follow up. Peri or post-operative complications were not an adverse predictor of physical function, pain or activity.

Conclusions: Predictors of quality of life outcomes after revision hip replacement-showed that although some patient specific and surgical specific variables were important, age, gender, Charnley class and baseline WOMAC function had the most robust associations with outcomes.

Revision of a failed acetabular reconstruction in total hip arthroplasty (THA) can be challenging when associated with significant bone loss. In cementless revision THA, achieving initial implant stability and maximising host bone contact is key to the success of reconstruction. Porous tantalum acetabular shells may represent an improvement from conventional porous coated uncemented cups in revision acetabular reconstruction associated with severe acetabular bone defects.

Methods: We reviewed the clinical and radiographic results of 46 acetabular revisions with Paprosky 2 and 3 acetabular bone defects done with a hemispheric, tantalum acetabular shell (Trabecular Metal Revision Shell, Zimmer, Warsaw, USA) and multiple supplementary screws for fixation.

Results: At a mean follow-up of 40 (24–51) months, one acetabular shell had been revised in a patient with a Paprosky 3B defect. Two liner revisions were performed for recurrent instability, without porous tantalum shell revision. The clinical outcome showed significant postoperative improvement in all measured sub-scales, compared with baseline pre-operative scores (mean improvement in Oxford Hip Score of 40.0, p < 0.001, in WOMAC of 36.7, p < 0.001, Physical component SF-12 of 12.3, p =0.0003, mental component of SF-12 of 6.8, p = 0.006). Radiographic evidence of osseointegration using validated criteria (Moore’s criteria) was demonstrated in 39 of the 40 hips available for radiographic analysis at a mean of 30.9 months, by two independent observers. Of the remaining six hips, five hips were lost to follow-up and one radiograph demonstrated failure of the hip reconstruction secondary to loss of fixation and superior migration of the component.

Discussion: Cementless acetabular revision with the porous tantalum acetabular shell demonstrated excellent early clinical and radiographic results in a series of complex revision acetabular reconstruction associated with severe bone defects. The evidence of radiographic osseointegration suggests that outcome should remain favourable, however, further longer-term evaluation is warranted.

Introduction: This single incision, anterolateral intermuscular approach (AL-IM) utilizes the interval between gluteus medius and tensor fascia lata. The aims of the study were to compare the quality of life, satisfaction and complications of this approach with two of the most commonly used limited incision transmuscular (TM) approaches, namely the mini-posterior (P-TM) and the mini-direct lateral (L-TM).

Methods: 199 patients receiving MIS THA surgical procedures were evaluated prospectively (63 AL-IM, 68 P-TM and 68 L-TM). The outcome variables were WOMAC function, pain, stiffness, SF-12 (physical & mental), Oxford-12, satisfaction and radiological outcome. Parametric and non-parametric analyses were performed.

Results: There were no significant differences between groups in baseline characteristics including age, sex, BMI, co-morbidity, or pre-op WOMAC, SF-12, Oxford-12 (p> .05). However, the AL-IM group was associated with superior outcomes (p< .05) in WOMAC function, WOMAC pain, global WOMAC, Oxford-12 and SF-12 physical component.

Conclusion: In the short term the AL-IM approach provides significant improvements in quality of life scores over other limited incision approaches. It provides minimal soft tissue disruption and maintains the abductor musculature and posterior soft tissue envelope, with similar complications and radiological outcomes.

To evaluate the results of open reduction in unreduced posterior dislocation of the elbow, done irrespective of the time since injury or age of the patient. Ten such cases in which the dislocation had been unreduced for more than 3 weeks since injury were included. Stiffness of the elbow was the main indication for the operation. Average age of the patient was 34.3 years (range 13 years to 65 years). Average time since injury was 3.9 months (range 2 month to 6 months). 3 patients had associated fractures around the elbow joint. All the patients had non functional elbow motion to perform any activity of daily living. We used speed’s procedure in all cases. At an average follow up of 18.5 months (range from 11 to 28 months), 8 patients achieved functional range of motion for activities of daily living and maintained an average arc of flexion(median) of 100 degrees and an average supination – pronation arc of 139.5 degrees. According to the Mayo Elbow Performance Index 5 patients achieved excellent results, 3 achieved good results and 2 achieved poor results. Complications included 2 cases of pin site infection, 1 case of ulnar neuritis and 1 case of delayed wound healing. We conclude that open reduction can provide painless, stable and functional elbow even in cases which are unreduced up to 6 months after the original injury.

Aim: To assess patient and surgery related factors to identify any trend leading to a stiff TKR. We also looked at the efficacy of MUA in the treatment of a stiff TKR.

Material and Methods: Retrospective analysis of TKRs which have undergone MUA during the period from 01/01/1999 to 25/06/2005 at Peterborough Hospitals. We included primary TKRs with a minimum post MUA follow-up of six months.

Results: Out of a total of 1809 TKRs, 42 TKRs (2.3%) in 38 patients required MUA. 26 (68%) were females with a median age of 67 years and a median BMI of 30. 34 (81%) had varus knees. Median pre-operative flexion was 100 deg. Median follow-up was 12 months (6 – 45 months). Median pre MUA flexion was 70 deg (15 – 100 deg.). Median surgery to MUA interval was 12 weeks (range: 10 days to 104 wks). Median gain in flexion during MUA was 35 deg (0 – 90 deg). At final follow-up, 74% had lost flexion gained at MUA (median loss: 17.5 deg, mean loss: 20 deg). 71% gained a median of 20 deg flexion with MUA (Mean: 25 deg, range: 15 – 85 deg). Median range of flexion at final follow-up was 90 deg (40 – 120 deg).

Conclusion: We were unable to identify any distinct trends in relation to BMI, pre op flexion, other patient or surgical factors that would help predict occurrence of a stiff TKR. We advocate the use of MUA for a stiff TKR. 71% patients gained 20 to 25 deg flexion with MUA. 74% patients lost about 20 deg flexion gained at MUA. The average post MUA flexion at final follow up was 90 deg. This information is useful when counselling patients undergoing MUA. A protocol for management of stiff TKR is suggested.

The study was established to assess the long-term results and differences between autogenous and synthetic anterior cruciate ligament (ACL) reconstruction.

We randomised 50 patients into 2 groups: 26 (52%) underwent reconstruction with middle third patellar tendon graft (PTG) harvested using the ‘Graftologer’ (Neoligaments) and 24 (48%) underwent reconstruction with the Leeds-Keio ligament (LK).

Subjective knee function was assessed using the Lysholm score, Tegner activity score, IKDC grading, and clinical assessment of anterior knee pain. Laxity was tested clinically, including anterior draw at 20° (Lachman), pivot shift, and arthrometric measurements using the Stryker laxometer.

At five years we have noted no significant difference in Lysholm scoring and Pivot shift between the LK group and patellar tendon group. But there was a significant difference in Tegner activity level and IKDC activity scores with PTG faring better at five years. There is no significance difference in anterior knee symptoms between the groups.

Conclusion: Due to the success of PTG/Hamstring in routine primary ACL reconstruction there does not seem to be a role for artificial ligaments. However, if we just look at functional outcome and patient satisfaction, LK patients seem to be doing as well as PTG at five years. So, there may be a place for the Leeds Keio graft where autologous tissue is unavailable.

There exists a lot literature referring to the cementing technique of hip replacements, but when talking about longevity of knee prostheses only seldom the cementing technique is mentioned even though 90% of the knees are cemented. Especially the tibial component, that has to cope with different forces such as pressure, rotation, tilt and sliding, is said to last longer when cemented.

Cementing Technique: There are many aspects that need to be thought of when cementing knee prostheses:

The preparation of the bone: The preparation of the surface of the bone is of great importance, as the-bond of the cement with the bone is by the shape of the surfaces and not by a chemical reaction. A good penetration of the cement into the cancellous-bone enlarges the connecting surface and optimizes the power transmission. The pulse-lavage is the most effective to open the spongy bone. Sclerotic bone needs to be penetrated.

When cementing knee prostheses one should give high attention to the cementing technique as especially a good anchorage of the tibial component will lead to longevity of the implant.

Introduction: Intra-Discal Electrothermal Therapy (IDET) has been used to treat chronic discogenic low back pain. A novel intradiscal decompression catheter has been developed to reduce local disc bulging in cases of contained prolapse. This new catheter is inserted percutaneously into a disc and advanced under radiographic control into a postero-lateral position targeting the herniation. The decompression catheter uses more focused heating and higher temperatures than previous devices and is intended to provide a local decompression of the disc through a thermally mediated reduction in nuclear volume. The purpose of this study was to investigate changes in internal stress profiles following use of the new catheter.

Methods: Five cadaveric lumbar ‘motion segments’ were dissected from two spines (age 64–84 yrs). Each segment was compressed, normally to 1 kN, while a miniature pressure transducer was withdrawn from posterior to anterior across the mid-sagittal diameter of the disc producing a baseline stress profile. A decompression catheter was inserted into the disc and its position confirmed with plain radiography. The temperature of the catheter was increased to 90°C over a period of 14 minutes. Stress profiles were then repeated.

Results: Stress profiles in three of the five segments showed changes consistent with degenerative change. In these discs stress profiles following ‘treatment’ showed up to a 35% reduction in the magnitude of stress peaks in the posterior annulus. There was very little change in the distribution of stress in the two non-degenerate discs. Stress in the nucleus appeared unchanged in all discs.

Conclusions: Treatment of degenerate discs with the decompression catheter lead to a measurable alteration in annular stress peaks associated with degenerative discs, while non-degenerate discs were unaffected. These preliminary findings of an ongoing study suggest that the novel decompression catheter has a biomechanical effect in certain classes of disc.

The study was established to assess the long-term results and differences between autogenous and synthetic anterior cruciate ligament (ACL) reconstruction.

We randomised 50 patients into 2 groups: 26 (52%) underwent reconstruction with middle third patellar tendon graft (PTG) harvested using the ‘ Graftologer ‘ (Neoligaments), and 24 (48%) underwent reconstruction with the Leeds-Keio ligament (LK).

Subjective knee function was assessed using the Lysholm score, Tegner activity score, IKDC grading, and clinical assessment of anterior knee pain. Laxity was tested clinically, including anterior draw at 20° (Lachman), pivot shift, and arthrometric measurements using the Stryker laxometer.

At five years we have noted a slight reduction in Lysholm scoring in the LK group, as well as reduced Tegner activity level. Pivot shift and laxity were significantly greater in the LK group.

Compared with earlier results, which showed little subjective difference between the groups, the autogenous PTG group show more sustainable long-term results than the synthetic (LK) group. There is no significant difference in anterior knee symptoms between the groups.

The aim of this prospective study is to investigate the effectiveness of a new method for arthroscopic all-inside meniscus repair (Clearfix meniscal screw system-Innovasive Devices Inc.).This system consists of delivery cannulae,screw implants and a screw driver.After tear debridement a screw is located on the driver and passed through the cannula to the insertion site, holding the two sides of the tear together under linear compression.In this study, 46 patients (48 repairs)are included, mean age 32,7 years,with a follow-up ranging from 6 to 48 months (average 18,8 months).Only longitudinal lesions in the red/red zone or red/white areas were repaired. Ligament stabilizing procedures were done in 39 patients (84,8%) who had ACL deficient knees,.Thirty-four (71%) injuries were considered chronic (injury to repair time more than 4 weeks) and 14 (29%) injuries were considered acute (injury to repair time less than 4 weeks).The evaluation of the results was based on the clinical examination,the “OAK ” knee evaluation scheme and the MRI.Criteria for clinical success included absence of joimt line tenderness, swelling and a negative Mc Murray test.Thirteen out of 48 repairs (27%) were considered as failures according to the above mentioned criteria.The average time for the procedure was 8 minutes.Postoperatively there were no complications directly associated with the device.Magnetic resonance imaging, however,showed a persisting grade III and IV lesion in 72,8% of the patients (n=35) according to Reicher classification.

Though the system offers two main advantages,that is the absence of serious complications and the reduced operative time, the failure rate in this study is quite high. This clinical study is in agreement with the recent experimental studies referring to the limited pull-out strength of this device.

Purposes of the study and background: Diagnostic interventional procedures are often performed on patients who suffer from cervical facet joint pain and discogenic pain emanating from the cervical region. These procedures require radiographic imaging to confirm placement of instruments e.g. needles. However, these techniques are unable to provide real-time images hence prolonging the intervention. It would be of benefit to have an imaging tool that is capable of visualising needle insertion in real-time whilst preventing side effects. The purpose of this study was to determine the ultrasonic appearance of cervical facet joints in vivo and describe a standardized transducer position to visualise intervertebral discs and facet joints.

Summary of the methods and the results: 10 healthy volunteers (age range: 21–36 years, 6 females, 4 males) were evaluated using an 8-16MHz linear array transducer (Diasus Dynamic Imaging). Subjects were scanned in a prone, lateral position. The transducer was placed in the posterior triangle orientated longitudinally, initially along the posterior border of sternocleidomastoid and then moved in a cranial-caudal direction. By adjusting the angle (in the antero-posterior direction) of the transducer about a fixed position; facet joints and discs were located. The characteristic V shaped appearance of the facet joint emanates from the hyperechoic signal of the closely spaced transverse processes of adjacent vertebra (Figure1). Disc regions appeared as areas of high signal penetration into the spine with low amplitude signals returning from the disc.

Conclusion: The detail of facet joint and disc anatomy captured using ultrasound reveal it to be a viable imaging tool for interventional procedures. Noteworthy advantages of ultrasound include: its ability to provide real-time images economically, the option of portability and no known side effects.

Purposes of the study and background: This study tests the hypothesis that it is possible to visualise the cervical spine musculature using ultrasound. The use of diagnostic ultrasound is well established for assessing other anatomical regions; whereas the cervical spine has received little attention. Other available imaging procedures can be resource intensive with recognized risks and do not give an indication of structural detail. Ultrasound has the potential to resolve these inadequacies and would therefore be appealing.

Summary of the methods and the results: 10 healthy volunteers (age range: 21–36 years, 6 females, 4 males) were evaluated using a 8-16MHz linear array transducer (Diasus Dynamic Imaging, UK) and a 16MHz CL15-7 linear array scanhead transducer (Phillips ATL HDI 5000 SonoCT, Netherlands). Subjects were seated with their neck in a neutral position. The transducer was orientated transversely, and initially placed on the thyroid cartilage. Successive images were taken as the transducer was moved laterally across the anterior triangle, over the sternocleidomastoid, into the posterior triangle, ending in the posterior midline. Landmarks, with characteristic ultrasonic appearances, were identified to aid orientation e.g. carotid artery. Both machines produced images that clearly displayed the musculature of the cervical spine. Composite images were obtained of the anterior and posterior aspects of the neck (Figure 1) to provide information regarding the spatial orientation and relationship between the muscles.

Conclusion: This study concludes that modern ultrasound equipment provides cervical spine soft tissue images of a quality suitable for diagnostic applications. It also has the advantages of being a risk free, economic and portable procedure.

There is a recognised incidence of anterior knee pain following Anterior Cruciate Ligament (ACL) reconstruction using a patella tendon autograft.

This study examined two group of patients both pre ACL ligament reconstruction and post ACL reconstruction using patella tendon grafts to define if anterior knee pain is a result of patella tendon harvest or a primary consequence of an ACL injury.

The two groups of patients were best matched for age, sex and physical activity.

The pre-operative group of twenty-five patients had a confirmed ACL rupture and exhibited symptoms of instability requiring an ACL reconstruction.

The operative group of twenty-five patients were a minimum of a year post operation.

The graft was harvested by an open procedure and the graft bone blocks were secured with interference screws.

The patients’ anterior knee pain score was assessed using the Shelbourne scoring system that evaluates knee function in relation to anterior knee pain using five parameters. The maximum score is 100.

The scores were compared using the unpaired student test.

There was no significant age difference between the two groups, preoperative group age 32. 2 years (range 22 to 46) and postoperative age 34. 8years (range 19 to 48).

The mean anterior knee pain score for the preoperative group was 71. 6 (49 to 100), the postoperative group was 77. 7 (45 to 100), this was not significantly different.

We found no significant difference in knee function due to anterior knee pain between the two groups. Studies have shown significant anterior knee pain following hamstring reconstruction (Spicer).

This study shows anterior knee pain in the ACL deficient knee is present prior to surgery.

We conclude that patella tendon autografts produce no significant incidence of anterior knee pain post surgery.

The purpose of this retrospective study was to analyze the indications for spinal instrumentation, report the clinical features, operative details and outcome in 16 patients with active pyogenic spinal infection.

Between January 1991 to October 1999, 81 patients with spontaneous pyogenic spinal infection were treated at the authors’ institution. Surgery (other than biopsy) was indicated in 24 patients for neurological deterioration, deformity or instability. Sixteen of these patients were treated with instrumentation in the presence of active spinal infection. Six patients underwent combined anterior and posterior procedures. 10 had a posterior procedure only. Outcomes assessed were control of infection, neurology, fusion, back pain and complications.

At a mean follow up period of 26. 9 months, all surviving patients were free of clinical infection. None of the patients had neurological deterioration. All patients who had neurological deficit preoperatively improved by at least one Frankel grade. A solid fusion was achieved in 15 patients. 12/15 patients remained asymptomatic or had very little pain. The remaining 3 patients had mild to moderate back pain. The mean correction of the kyphotic deformity was 18. 92 degrees. Postoperative complications included bronchopneumonia, nonfatal pulmonary embolism and seizures in 3 patients. One patient developed progressive kyphosis despite instrumentation but eventually fused in kyphus.

Given early recognition of pyogenic spinal infection, most cases can be managed non-operatively. Our results support that instrumented fusion with or without decompression may be used safely when indicated without the risk of recurrence of infection. Instrumentation facilitates nursing care and allows early mobilisation. For biomechanical reasons, a combined procedure is probably indicated for lesions above the conus. For lesions below the conus, we were able to achieve successful results with posterior approach only.

We have performed a study comparing the radiological results of Total hip replacements performed by a single, experienced specialist hip surgeon with those reported from the Trent Regional Arthroplasty Study (TRAS) [presented at BOA congress 2000]. Results from TRAS have revealed that inadequate cementation grades and a cement mantle width of < 2mm were the most significant associations predicting early aseptic loosening. Interestingly, their respective incidences were as large as 20% and 50% in a random sample of THRs from the TRAS register.

Data is lacking as to whether poorer radiographic cementation grades have a trend towards individual surgeons or whether they are more evenly distributed amongst the surgical population including those adhering to modem techniques.

Therefore, we have undertaken an independent review of A-P and lateral radiographs of 33 consecutive Charnley THRs performed by a specialist hip surgeon using carefully controlled modem cementing techniques and compared the results with the same random cohort of THRs from the TRAS.

Our results show that the specialist surgeon achieved a significantly higher proportion (82%) of complete cement mantles (> 2mm in all zones) than those achieved by TRAS (50%) [Chi²=7. 79, p=0. 0052]. This suggests that improved cement mantles can be achieved by the adoption of carefully controlled modem cementing techniques. However, use of the Barrack system of grading was unable to detect differences in cementation quality between specialist (88%) and TRAS group (81%) [Chi²=0. 235; p=0. 631 suggesting less sensitivity in this technique for assessing cementation quality. These results are important for the following reasons. Achievement of adequate mantle (> 2mm) can be improved upon by adoption of carefully controlled modem cementing technique. However, regardless of the method of assessment of cementation quality, approximately 18% will appear ‘inadequate’ despite modern techniques suggesting that factors outside the surgeon’s control are involved in determining cementation grade. This has important medico-legal implication in the current climate in which surgeons are being criticised, in negligence cases arising out of the 3M Capital Hip experience, for achieving ‘inadequate’ cementation.

Aims: To determine which radiological features were most significant in aseptic loosening (AL) of Charnley total hip replacement (THR) and to compare the prevalence of these features between a specialist hip surgeon and those from the general setting. Method: An analysis was performed of the initial post-operative radiographs of three groups of Charnley femoral stems: I: Failed stems within 5 years due to AL, as registered in the Trent Regional Arthroplasty Study (TRAS). II: 44 consecutive Charnley THRs performed by a single, ‘specialist’ hip surgeon. III Controls: A randomly selected cohort group from the TRAS (proven to be clinically and radiologically intact at 5 years). Results: The most significant radiographic features of failure were: (i) mantle width < 2mm in any zone giving an odds ratio of 21.0 for failure (CI 3.3 to∞; p< 0.05); (ii) “inadequate” cementation grade (Barrack grades C and D) giving an odds ratio of 9.5 for failure (CI 3.2 to 28; p< 0.05). The specialist hip surgeon achieved a significantly higher proportion (79.5%) of complete cement mantles (> 2mm) than the controls (50%) (Chi^2 = 9.455, df = 1, p=0.002). There were also a higher proportion of adequate cementation grades (88.6% vs 82%) although this difference was not significant (Chi^2= 0.947, df = 1, p=0.330). Conclusion: We have demonstrated features identified on radiographs of Charnley femoral stems predictive of failure. In our study a specialist hip surgeon achieved fewer flaws than those detected across a regional ‘average’. This suggests surgical technique can influence radiological results and thus outcome. This needs to be emphasized, particularly during training, in the hope of improving overall results in the future. However, even a specialist’s cementation appeared inadequate in 11.4% of cases, suggesting that factors outside the surgeon’s control, influence cement grading. This is important from a medico-legal standpoint because surgeons are being criticised for not achieving adequate cementation in negligence cases.

The corticosteriods in the treatment of Duchenne’s or Becker’s muscular dystrophies causes muscular weakness and osteoporosis characteristic of these patients and result in different fractures which are of difficult resolution because prolonged immobilization increases morbidity. How can this problem be solved in highly risk patients? The diverse models of external fixators have given us the possibility of treating them without immobilization and in consequence obtain a quicker return to previous functional status including gait .

4 patients with Duchenne’s and Becker’s muscular dystrophies were treated. 1 patient recovered its ambulatory ability and the rest maintain their gait. 1 of them still has an external fixator but he is able to walk. Patients presented a diaphyseal fracture of the femur, a proximal fracture of the tibia, an introchanteric fracture of the hip and a supracondylar fracture of the femur.

We consider that external fixators open an endless range of options, not very much used until recently, that help our patients to extend their functional status and gait. Patients accept them easily because they give them independence and avoid the depression that stems from the loss of capabilities.

Objective: To assess the validity of the Tokuhashi and Tomita scoring systems in the prediction of prognosis following spinal surgery for skeletal metastases.

Design: A retrospective cohort study of patients treated in a specialist spinal unit

Subjects: All patients undergoing definitive surgery for metastastes of the spine were considered eligible. Time to death or current length of survival was available in 147* of these which was confirmed by the Cancer Registry. Medical and nursing case notes were reviewed and prognostic scores using the methods of Tokuhashi et al, and Tomita et al. were calculated for each patient.

*

death data for further patients currently awaited from Cancer Registry.

Outcome measures: Mean survival period with 95% confidence intervals for patients grouped according to prognostic score.

Results: Thirty-two patients were still alive and 113 had confirmed death dates. Forty-three patients had Tokuhashi scores of 9 or greater with a mean survival of 20.1 months (95% confidence interval 5.8 months) compared to 9.5 months (2.9 months) for scores 6–8 and 3.5 months (1.8 months) for scores below this. Tomita scoring showed a similar trend with those with better prognostic profiles but without the same degree of statistical significance. The overall 30-day mortality was 8.2% with no significant difference between any other groups.

Conclusion: In patients presenting with metastatic disease involving the spine, published prognostic profiles offer some guidance to likely survival of the patient and so the appropriateness of surgical treatment.

Aim: We conducted a prospective, randomised study of 50 patients, 40 (80%) male and 10 (20%) female, with anterior cruciate ligament (ACL) rupture to compare the results of ligament reconstruction by middle third patellar tendon graft (M) or synthetic Leeds-Keio (LK) ligament.

Method: The patients were randomised into two groups. 26 (52%) underwent PTG repair and 24 (48%) LK repair. Subjective knee function was classified using the Lysholm score, Tegner activity score and IKDC grading. Laxity was tested by clinical examination including anterior draw, pivot shift and arthrometric measurements using the Stryker Laxometer (Stryker Corporation, Kalamazoo, Michigan, USA).

Results: We present the early (two to five-year follow-up) results of this on-going trial. There was no statistical difference between the two groups in activity levels, both pre-injury and current. However, both pivot shift and anterior laxity were significantly greater in the LK group at two years and greater.

Discussion: While the LK group did develop significantly greater laxity, it is demonstrated that the functional outcome is not affected. We conclude therefore that if the results of surgery were to be based on a functional outcome rather than objective measurements of laxity, it would seem logical that the LK is an acceptable alternative to autogenous PTG.

However whilst function appears to be as good the less successful objective criteria do suggest reservations for the long term results of the Leeds-keio graft.

Objective: To measure intradiscal pressures in scoliotic spines to further understand the role of mechanical forces in the development of scoliosis.

Design: Pressure readings were obtained in consented patients with ethical approval. A needle mounted pressure transducer was introduced into the disc during routine anterior scoliosis surgery.

Subjects: Ten human scoliotic discs from three patients.

Outcome measures: Intradiscal pressure profiles.

Results: Nuclear hydrostatic pressures varied from 0.2 to 0.6 MPa. The mean nuclear pressures for the three spines were 0.27+0.12, 0.35+0.06 and 0.47+0.12 MPa.

High stress, non- hydrostatic regions were consistently recorded in the concave annulus.

Conclusions: Nuclear pressures in these scoliotic patients were significantly higher than the 0.12 and 0.15 MPa recorded previously in non-scoliotic recumbent individuals^1;2 suggesting that spinal loading is abnormal in scoliosis.

Introduction: The progress of post tubeculous kyphosis in children during ‘growth spurt’ is unpredictable and has not been clearly documented in literature.

Methods: The progression of deformity in 63 children treated conservatively and belonging to a controlled clinical trial was studied over 15 years.

Results: The average Kyphosis increased from 35.2 degrees to 41.3 degrees in the ‘Active Stage’ (Phase I), there was an increase in all patients. In the ‘Healed stage’ (Phase II), a variable progress continued which was more prominent during the ‘growth spurt’. In Type I, there was a worsening which occured either continuously (Type 1a; n=19.30%), or suddently after a gap of few years (Type 1b;n=6.9%). In Type II, an improvement occured either after an initial increase or a plateau (Type IIa; n=18.29%), or continuously after disease cure (Type IIb; n=9.15%). In Type III, the deformity was static (n=11.17%). The average increase in Type Ia was 24.2 degrees, Type IIb was 20;5 degrees, Type Ib was 58.4 degrees; the decrease in Type IIa was 4.9 degrees, Type IIb was 20.5 degrees and the decrease in Type III was 1.7 degrees. Overall, the growth spurt sresulted in an increase in deformity in 25 (39%) children, a decrease in 27 (44%) and no change in 11 (17%).

Conclusion:

Post-tuberculous kyphosis in children is a ‘Dynamic deformity’ which changes till skeletal maturity.

Many factors have been demonstrated to influence the range of knee movement that an individual can achieve.

The purpose of this study was to objectively demonstrate how range of knee movement is affected when the influence of pain is abolished.

Sixty-eight patients with degenerative joint disease presenting for primary total knee arthroplasty were recruited. Using a digital camera, images were taken before and after the induction of anaesthesia with the lower limb in four positions- extension, forced extension, flexion and forced flexion. Camera set up was standard and the range of knee motion was measured from the digital images.

Average arc of motion before anaesthesia was 96° (range, 41°–157°). After induction of anaesthesia, the arc of motion increased to 115° (range, 410–161°). Knee extension improved by an average of 5° (range, 0–15°) and flexion improved by an average of 16° (range, 0–65°).

In conclusion, these results demonstrate that pain has a significant inhibitory effect on the measured range of knee movement before surgical intervention.

The aim of this trial was to assess the clinical examination findings commonly used for the ACL deficient knee.

For reliability testing and criterion validation 102 patients with ACL injuries were assessed by a single observer, 35 by a second observer and 47 again by the initial observer. For construct and criterion validation 30 patients were assessed pre-operatively and a mean of 1.7 years after ACL reconstruction. The Lysholm 11, Tegner and Cincinnati outcome measures were assessed along with instrumented knee laxity (Stryker test), the one hop test (OHT) and graded tests (including anterior draw, Lachman test, quality of end point, and pivot shift test).

The outcome measures were found to be reliable except the Cincinnati system. All examination findings were of unsatisfactory reliability, with the exception of the OHT and the Stryker test. Construct validation revealed a significant improvement in all outcome measure scores and examination findings following ACL reconstruction. Criterion validation revealed that of the examination findings only the OHT had a satisfactory correlation with the symptom of giving way and the Lysholm/Tegner measures. Comparison of the difference between the desired and actual Tegner activity levels with the examination findings revealed an improvement in all levels of correlation.

With the exception of the OHT, the clinical examination findings used for the ACL deficient knee are unreliable and correlate poorly with the functional outcome of the patient. They may, however, have some benefit in assessment of deficiency of the anatomical structures and the findings should be presented individually, rather than forming part of the functional assessment of the patient.

Dislocation of the polyethylene-rotating platform is a recognised complication of LCS knee arthroplasty.

We report ten cases of rotating platform dislocation out of 2151 primary total knee arthroplasties (0.5%) performed to date in our unit.

Of the ten cases (3 male: 7 female), six patients had a preoperative valgus deformity, two had a varus deformity and the remaining two patients were in neutral alignment, although the wear was predominantly within the lateral compartment. Two patients also had a previous patellectomy on the side of the platform spinout.

Of the ten cases, six patients were symptomatic as a result of their platform dislocation. The remaining four patients were asymptomatic and mobilising without any difficulty. In these patients, the dislocated platform was diagnosed on x-ray at outpatient review. Time to detection of the platform dislocation ranged from six days to two years.

Three patients required revision of their original insert to a larger, deeper dish insert. Three were managed by open reduction of the original insert. Of the remaining patients, one was managed successfully by closed reduction, one required an arthrodesis and one had the tibial insert cemented to the tibial tray. All patients at latest review have a functional and stable knee joint.

In conclusion, we feel that surgical error was to blame for the majority of our ten cases. Furthermore, we emphasise the importance of producing equal and balanced flexion and extension gaps at the time of knee arthroplasty in order to prevent mobile bearing dislocation. A novel technique for reducing a dislocated rotating platform is also described.

The aim of this randomised prospective study was to establish whether the use of knee splints following total knee replacement is necessary.

The study included 81 patients undergoing total knee replacement who were randomised into a ‘splint’ and a ‘no splint’ group postoperatively. Patients in the ‘splint’ group had their knee splinted in extension in the early post-operative period but the splint was removed for the patients to do exercise. Splintage was completely removed when the patient could straight leg raise. Patients in the ‘no splint’ group had a wool and crepe bandage applied around their knee and allowed to fully mobilise from the first postoperative day. The following parameters were recorded: The range of movement preoperatively, 5 days post-operatively and 6 weeks postoperatively; the length of time to straight leg raise; the blood drained from the wound. and the amount of postoperative analgesia required.

Using the unpaired 2 tailed t-test it was found that patients in the four ‘no splint’ group achieved significantly greater flexion at 5 days and 6 weeks post-operatively but drained significantly more blood from the wound. Transfusion requirements were similar in the two groups. There was no other significant difference in the parameters measured between the two groups.

In conclusion we found no evidence to advocate the use of knee splints following total knee arthroplasty.

Purpose: Posters of study: To produce a virtual reality model of prosthetic knee joint motion, giving detail regarding contact area and contact pressures during the process of walking.

Method: Using serial CT scans and data regarding the material properties of bone, cartilage, ligaments and other soft tissue structures a computational “virtual reality model” of the knee has been constructed. This computational model which is a 3D dynamic representation of a human knee joint, may be programmed to replicate the standard gait pattern of the human knee.

This study details the development of this model and its validation against the accepted Stenmore Test Rig for modelling of knee joint movement and knee prosthetic wear. The validation results will be presented,

The model allows the calculation and representation of contact pressures and contact areas in the knee joint as it moves through the gait cycle. This study also shows the effect of uni-condular loading and varus mal-positioning which may occur at surgery and the effect this has on the contact area and contact pressures of a prosthetic knee in ambulation. The resultant gait pattern produced by uni-condular loading and exhibited by the virtual knee closely resembles that seen in In Vivo Kinematic Studies reported by other authors.

In conclusion we present this as a valid computational dynamic model of knee prosthetic wear and kinematics which represents an enormous advantage over standard mechanical testing and presents possibilities for rapid analysis in new knee joint designs and the effect of abnormalities of gait and wear.

Two dimensional ultrasound of the shoulder joint has become a well established diagnostic tool. Difficult interpretation of ultrasonographic findings, however, suggests that ultrasound appears not to be an always reliable method, especially in partial thickness tears. The present study was performed to determine whether the use of three dimensional (3D) sonography further increases the diagnostic yield of ultrasound.

On a total of 22 externally intact appearing rotator cuffs of cadaveric shoulder joints 7 full thickness and 15 partial thickness incisions were carried out on the M. supraspinatus, subscapularis and infraspinatus tendon. The specimens included the humeral head, the glenoid, the joint capsule and periarticular tendons.

Ultrasound was performed on the shoulder specimens in a water basin with a 8.5 MHz curved array transducer (Combison 530D, Kretztechnik, Zipf, Austria).

With three dimensional ultrasound rotator cuff lesions were more often correctly diagnosed (sensitivity of 77 %) than with conventional 2D sonography (sensitivity of 64 %). Specificity was 85 % and 69 %, respectively. In partial thickness tears in particular, 3D imaging was the superior method reaching a sensitivity and specifity of 73% and 77%, respectively compared to 53% and 61%, respectively with 2D ultrasound.

The use of three dimensional ultrasound appears to have a higher diagnostic yield in partial thickness tears. One advantage is that the examiner must not move the transducer to obtain other planes. Changes in echogenicity can be observed in the complete volume and in any plane. In the diagnosis of partial tears these changes enabled the examiner to distinguish intact from ruptured tissue.