Aims

Metal and ceramic humeral head bearing surfaces are available choices in anatomical shoulder arthroplasties. Wear studies have shown superior performance of ceramic heads, however comparison of clinical outcomes according to bearing surface in total shoulder arthroplasty (TSA) and hemiarthroplasty (HA) is limited. This study aimed to compare the rates of revision and reoperation following metal and ceramic humeral head TSA and HA using data from the National Joint Registry (NJR), which collects data from England, Wales, Northern Ireland, Isle of Man and the States of Guernsey.

Aims

With up to 40% of patients having patellofemoral joint osteoarthritis (PFJ OA), the two arthroplasty options are to replace solely the patellofemoral joint via patellofemoral arthroplasty (PFA), or the entire knee via total knee arthroplasty (TKA). The aim of this study was to assess postoperative success of second-generation PFAs compared to TKAs for patients treated for PFJ OA using patient-reported outcome measures (PROMs) and domains deemed important by patients following a patient and public involvement meeting.

Abstract

Studies have shown that 10–30% patients do not achieve optimal function outcomes after total hip replacement (THR). High quality randomised controlled trials (RCTs) evaluating the clinical and cost-effectiveness of techniques to improve functional outcomes after THR are lacking. We performed this study to evaluate the feasibility of a RCT comparing patient-reported functional outcomes after hybrid or fully cemented THR (ISRCTN11097021).

Patients were recruited from two centres and randomised to receive either a fully cemented or hybrid THR. Data collection included Patient Reported Outcome Measures (PROMs), non-serious adverse events of special interest (AESI), serious adverse device effects (SADE) and NHS resource use. Qualitative interviews were undertaken to understand a) patient experiences of study processes and their reasons for taking part or not, and b) to understand surgeons’ perceptions of the study, factors affecting willingness to participate, and barriers to implementation of the future RCT findings.

The target of 40 patients were successfully recruited for the feasibility RCT; the ratio of successful recruitment to eligible patients was 0.61 across both sites. Treatment crossovers occurred in four patients, all related to bone quality. Four patients were withdrawn due to not undergoing surgery within the study window because of the pandemic. Follow-up was 100% and PROMs were completed by all patients at all time points. The feasibility of conducting a within-trial cost-utility analysis was demonstrated. Interviews were conducted with 27 patients and 16 surgeons. Patients and surgeons generally found the study procedures acceptable and workable. Some declined participation because they did not want treatment allocated at random, or because blinding was off-putting. Surgeons’ perceptions of equipoise varied, and implementation of findings from the future RCT would need to recognise the ‘craft’ nature of surgery and the issue of training.

We conclude that a full RCT with economic analysis will be both feasible and practicable, although mechanisms to safely implement potential changes to practice because of RCT findings may need consideration by the wider arthroplasty community.

Abstract

Abstract

The Coronavirus pandemic mandated an immediate and dramatic change in the delivery of acute trauma services to minimise face-to-face contact. In our hospital, patients presenting to the Emergency Department with a knee injury and no fracture seen on Xrays were referred to a “Virtual Fracture Clinic” (VFC) where Xrays and clinical notes were reviewed by the duty Trauma and Orthopaedic Consultant the following working day. We present the outcomes of 101 consecutive patients managed through this process and deemed to have a “Soft Tissue Knee Injury” with a minimum follow-up of six months.

All Xrays were reviewed by a sub-specialist knee surgeon blinded to notes or clinical outcomes. Electronic clinical records were reviewed to determine further clinical appointments, surgical treatment and pending interventions.

Of 101 patients, the knee surgeon diagnosed 1 Fracture, 4 Lipo-haemarthroses, 41 significant effusions and 55 patients with normal Xrays. Correlation to urgent surgery was 100% for fracture (1/1), 25% for Lipo-haemarthrosis (1/4), 7.3% for significant effusion (3/41) and 9.1% for normal Xrays (5/55). A further 9.8% (4/41) of the “effusion” group and 7.3% (4/55) of the “normal” group were subsequently listed for non-urgent surgery.

Overall 17% (7/41) of “effusion” patients and 16% (9/55) of “normal” patients required surgery. Management plans from VFC varied within groups.

Acute “soft-tissue” injuries of the knee in adults cannot be reliably managed via VFC based on X-ray findings. A staged review by an appropriately trained health professional could reduce demand on acute knee surgical clinics and may enhance patient outcomes.

The ODEP (Orthopaedic Data Evaluation Panel) rating system should offer a surgeon and patient extra information when making a choice on which implant to use. However, in the current economic environment, ratings may also influence implant choice by contracting bodies. Our aim was to determine the performance of commonly used Acetabular and femoral components in our unit and compare these to their published ODEP ratings (or absence of rating).

We analysed all of the following primary THR components (12,792) for revision for any reason, using same date ranges as ODEP where more than 100 implantations had occurred. Hip components: Trinity (3A in 2013), Trilogy (10A* in 2016), Atlas (10A in 2013), Trilogy TMT (10A 2010) Durom (not rated), BHR (10A, 2010), ACCIS (not rated); Femoral components: Taperfit (10A in 2013), Taperloc (10A* in 2016), Metafix (3A in 2013), CPT (10A in 2012), Ecofit (not Rated), ESOP (not rated), Minihip (3A 2013), Durom (not rated), BHR (10A 2010), ACCIS (not rated).

Analysis of Kaplan Meier survival curves was undertaken for all components. The rated components and non-rated components were compared using HR and logrank tests for all time groups when ratings were introduced. No statistical difference was observed in any group except for the Trinity cup which had a 98.2% (1344 cups) survival at 6 years.

Component survival in our unit was better than ODEP suggested failure for A category of not more than 1% per year, for all components.

Whilst we applaud the intention to improve data available for prostheses, the present ODEP system does not distinguish between performances of different implants in our unit. We therefore recommend care when relying upon ODEP ratings to make clinical or contracting decisions.

Introduction

There is little information available to surgeons regarding how the lateral soft-tissue structures prevent instability in knees implanted with total knee arthroplasty (TKA). The aim of this study was to quantify the lateral soft-tissue contributions to stability following cruciate retaining (CR) TKA.

Aim

The purpose of this study was to quantify the number of children treated with ESIN (elastic stable intra-medullary nails) at our institution and to determine what proportion of these nails have been removed and the time and difficulty taken to do so.

A study to assess the clinical importance of asymmetric thigh creases as the sole clinical sign in the diagnosis of developmental dysplasia of the hip.

Aim

To evaluate the influence of arthrodiatasis in the natural history of the stages of the disease radiologically and also the timing of arthrodiatasis.

Introduction

The advent of double bundle ACL (Anterior Cruciate Ligament) reconstruction had been hailed as potentially allowing for more anatomically and physiologically functioning graft, however until recently there had been little evidence of enhanced functional outcomes.

The aim of this study is to explore whether the dimensions of hamstring two strand single bundle grafts, are predictive of the combined four strand single bundle graft that results from combining the single bundle grafts, as well as the impact of double bundle grafts upon the available healing and attachment area within the bony tunnels.

Subtalar dislocation of the hindfoot is a rare injury and can be associated with poor functional outcomes. We report a case of an irreducible subtalar dislocation in an elite athlete, who returned to elite sport.

A 28 year old competitor in the world mountain bike championships was injured in a high speed fall from his mountain bike during a competitive downhill run in July 2007. He had an obvious deformity at the scene and a fracture dislocation of the ankle was suspected. The injury was closed and neuro-vascular status was intact. Radiographs revealed the ankle mortise was intact with the talus anatomical, but a subtalar dislocation was present which proved irreducible in the emergency department.

The patient was taken to the operating theatre and the dislocation was reduced through a short antero-medial arthrotomy using a blunt lever and traction. Post- reduction, the joint was stable and was supported in a below knee cast. He was kept partial weight bearing for 6 weeks and then had an intensive physiotherapy rehabilitation regime. Serial radiology showed no evidence of avascular necrosis or other skeletal abnormalities.

Our patient has since returned to elite Mountain Biking and won the British National Championships in 2008 and the World Championships in Canberra in 2009.

The aim of this study was to assess the increase in the anterior diameter of the knee and the impact of this increase on the range of motion and function of the knee.

Twenty-eight patients (34 knees) who underwent Patello-femoral replacement with FPV (Wright Medical) prosthesis between 2005 and 2009 who were identified retrospectively and analyzed using chart and radiological review. Oxford and AKSS knee-scores were gathered prospectively pre-operative and at follow-up.

Trochlear height was measured using lateral radiograph. Trochlear height was compared pre and postoperatively. Patellar height was also measured in preoperative and postoperative skyline view and was compared. The range of movement at six weeks and the Oxford and American knee society knee scores at six months postoperatively were noted. Association between increased anterior height and improved range of motion was studied.

All but three-knees regained full knee extension. Postoperative mean range of flexion of the knee joint was 116 degrees. The mean Oxford knee and the mean American Knee Society Knee Scores significantly improved post-operatively

The trochlear height was increased by 4mms. Patellar height was also increased by 3 mms resulting in average total increase of 7 mms in the anterior-posterior diameter of the knee. We found no relationship between range of motion of the knee and the increase in the anterior-posterior diameter. We found a negative correlation between increase in the antero-posterior and preoperative trochlear and patellar height.

We conclude that FPV Patello-femoral replacement results in correct anatomical reconstruction of the trochlear height rather than ‘overstuffing’ of the patellofemoral joint which can lead to stiffness and failure of resolution of pain post-operatively. This should in turn result in durable improvements in pain and function.

Patellofemoral unicompartmental joint replacement is a controversial subject with a relatively small evidence base. Of the 50,000 total knee arthroplasties performed each year in the UK, approximately 10% are performed for predominantly patellofemoral arthritis. There are several patellofemoral unicompartmental prostheses on the market with the National Joint Registry recording 745 such prostheses used in 2007. Most evidence in favour of this procedure comes from experience with the Avon prosthesis (Stryker) predominantly from designer-surgeons.

The FPV patellofemoral joint replacement (Wright Medical) has been in use in Europe for several years. The instruments have recently been redesigned and the device marketed in the UK. In 2007 the FPV had 5.9% market share (n=44). We present our early experience with the FPV patellofemoral joint replacement, which to our knowledge, is the first clinical outcome series for this prosthesis.

33 consecutive FPV joint replacements in 29 patients were performed between April 2007 and September 2009 for unicompartmental patellofemoral OA. All cases were performed or directly supervised by the senior author. Results are presented with a minimum follow-up of six months.

Oxford and American Knee Society scores (AKSS) were obtained on all patients preoperatively and at subsequent outpatient visits. Mean preoperative AKSS knee score was 49.7 points and postoperative scores at 6 months and 1 year were 82.5 and 86.4 respectively. Mean Oxford score preoperatively was 30.4 (37%) and at 6 months and 1 year were 21.3 (56%) and 11.2 (77%) respectively.

There were no complications related to the implant. One knee required a secondary open lateral release due to inadequate balancing at the index procedure.

Further medium to long-term follow up data are required, but our initial experience with this device is encouraging.

Patellofemoral unicompartmental joint replacement is a controversial subject with a relatively small evidence base. Of the 50,000 total knee arthroplasties performed each year in the UK, approximately 10% are performed for predominantly patellofemoral arthritis. There are several patellofemoral unicompartmental prostheses on the market with the National Joint Registry recording 745 such prostheses used in 2007. Most evidence in favour of this procedure comes from experience with the Avon prosthesis (Stryker) predominantly from designer-surgeons.

The FPV patellofemoral joint replacement (Wright Medical) has been in use in Europe for several years. The instruments have recently been redesigned and the device marketed in the UK. In 2007 the FPV had 5.9% market share (n=44). We present our early experience with the FPV patellofemoral joint replacement, which to our knowledge, is the first clinical outcome series for this prosthesis.

33 consecutive FPV joint replacements in 29 patients were performed between April 2007 and September 2009 for unicompartmental patellofemoral OA. All cases were performed or directly supervised by the senior author. Results are presented with a minimum follow-up of six months.

Oxford and American Knee Society scores (AKSS) were obtained on all patients preoperatively and at subsequent outpatient visits. Mean preoperative AKSS knee score was 49.7 points and postoperative scores at 6 months and 1 year were 82.5 and 86.4 respectively. Mean Oxford score preoperatively was 30.4 (37%) and at 6 months and 1 year were 21.3 (56%) and 11.2 (77%) respectively.

There were no complications related to the implant. One knee required a secondary open lateral release due to inadequate balancing at the index procedure.

Further medium to long-term follow up data are required, but our initial experience with this device is encouraging.

We report the clinical results of seven consecutive allograft knee ligament reconstructions using Achilles tendon prepared using a chemical treatment process. Results have been disappointing with six clinical failures at short durations of follow-up. All allografts are not the same and the method of tissue preparation may have important consequences for clinical outcomes.

Debate regarding the use of allograft or autograft tissue for knee ligament reconstruction continues. A variety of allograft tissues are available from commercial and NHS sources: fresh frozen, freeze dried, irradiated or chemically prepared. There are gaps in the literature with respect to clinical outcomes for these various methods of graft preparation. A recent systematic review indicated similar short-term clinical outcomes for fresh frozen allografts and autografts.

The senior author began using allograft Achilles tendon for revision ACL reconstruction or primary multiple ligament reconstruction in 2007. Tissues were obtained from a commercial supplier. These tissues had been harvested in Eastern Europe, transported to the USA and sterilised using a patented “Biocleanse” chemical treatment process. This involves sequential ultrasonic baths of detergent, peroxide and alcohol for fixed periods of time along with pressure and vacuum cycles.

Between April 2007 and April 2009, 7 allograft ligament reconstructions were performed in 5 knees. These comprised 5 ACL and 2 LCL reconstructions. At follow up of between 4 months and 2 years, clinical failure of 6 grafts has been observed. We are aware of one previous series of results for ACL reconstructions using chemically sterilised and irradiated allograft tissues. A 45% graft failure rate was reported. We have not been able to identify any clinical outcome studies for grafts prepared using the “Biocleanse” process.

Our results have prompted us to change to UK sourced, donor screened allografts, which are fresh frozen after decontamination with 70% ethanol.

Aim: To review our experience with epiphysiodesis using three different methods to correct LLD and to establish the efficacy of these procedures.

Method: A retrospective review of 42 patients from 1999 to 2008 with at least one year follow-up recorded type and location of the epiphysiodesis, average operating time and hospital stay, complications, method of prediction, timing and the final LLD. CT scanograms and mechanical axis view with grids were used to assess LLD.

Results: Epiphysiodesis was as per Canale for 26, by Metaizeau screw in 14 and by staples in 2. Average operation time was 42 minutes for Canale type, 45 minutes for the screws and 56 minutes for the staple cases. The pre operative LLD of 3.7 cms In the Canale group, improved to 1.2 cms over an average follow-up of 2.1 yrs. There were 4 minor and 2 major complications with a 92% success rate. For the screw group, the mean change was 1.8 cms over 2.2 yrs with 2 minor and 2 major complications giving a success rate of 85%. With staples the success rate was 100% and the mean change was 1.8 cms at an average of 2.3 yrs. In 14 cases where bone age reports were available, the multiplier method seemed better at predicting estimated LLD at skeletal maturity and timing of epiphysiodesis than the Moseley chart.

Conclusions: Percutaneous epiphysiodesis by any method is reliable, minimally invasive and with acceptable complication rate when compared to a corrective osteotomy or open Phemister-type epiphysiodesis. Our experience suggests that the Canale method has the least complications and best success rate. Paleys multiplier method was better at predicting LLD and timing of epiphysiodesis than the Moseley Chart.

The study aims to determine the effects of obesity on the patients’ symptoms and their knee function before knee arthroplasty, as well as their states of anxiety and depression.

Ethical approval was obtained before the start of the study. Weights and heights of all patients were measured and BMI calculated on admission. Anxiety and depression states were recorded using the Hospital Anxiety and Depression Scale (HADS). The severity of pain and loss of function of the knees undergoing arthroplasty was measured using the Oxford Knee Score and the American Knee Society Score. All scores were measured per-op and again at 6 weeks post-op.

To date, 28 patients were included. The mean body mass index was 28.9. Only six patients had a BMI of < 25. Patients with normal BMI (< 25) had mean anxiety and depression scores of 6.8 and 5.67 respectively. Overweight patients (BMI > 25) had scores of 5.59 and 4.9 respectively. Patients with BMI > 30 had scores of 6.71 (p= 0.22) and 7.0 (p= 0.04) respectively.

Patients with BMI > 30 had an improvement in anxiety scores of 1.33 points compared with 0.55 for patients with BMI < 30 (p= 0.3). Depression scores improved by 4 points in the BMI > 30 group compared with 0.67 in the BMI < 30 group (p= 0.03).

Improvements in the knee scores were comparable in both groups.

Obese patients with BMI of > 30 have higher rates of anxiety and depression pre-operatively. At 6 weeks follow up, there is an improvement in both measures of psychological distress but this is more pronounced for depressive symptoms.

Aim:This study was carried out to assess various factors responsible for the development of avascular necrosis and the effect of treatment on clinical outcome.

Methods: We studied the clinical notes and radiographs of patients presenting with SCFE during the period between 1994 and 2003.

Results: Seventy three patients (n=73) with ninety two (n=92) hips were included in the study. There were 16 acute, 43 acute-on-chronic, 29 chronic and 4 preslips. Seventy Seven (n = 77) slips were classified as stable and 15 as unstable slips. Fifty three slips (57.6%) were mild, 34 (37%) were moderate and five (5.4%) were severe slips. Despite no deliberate attempts to reduce the slip at the time of surgery eighteen hips (n=18) showed a median decrease in slip angle of 8 degrees (range 2–36) in acute and acute-on-chronic slips. The mean preoperative slip angle was 32 degrees (range 9–76) compared to postoperative slip angle of 29.9 degrees (range 10–75) (p=0.004). Four patients developed avascular necrosis (AVN). Intraoperative reduction of the slip was significantly related to development of AVN (p< 0.001). According to the criteria of Heyman and Herndon eight patients had functional deficit at the time of final follow up and clinical outcome was fair, poor or failure. All of these patients had a reduction in the angle of slip at the postoperative radiographs compared to their preoperative radiographs.

Conclusion: Reduction of slipped capital femoral epiphysis is responsible for poor outcome and also related to the development of avascular necrosis. We recommend single in situ pinning for these cases regardless of severity of slip.

Cobalt chrome-on-cobalt chrome bearing surfaces have been re-introduced despite some concerns regarding potential risks posed by soluble metallic by-products. We have investigated whether there are metal-selective differences between the levels of genetic damage caused to a human cell line when cultured with synovial fluids retrieved from various designs of orthopaedic joint replacement prostheses at the time of revision arthroplasty.

Synovial fluids were retrieved from revision hip and knee arthroplasty patients with bearings made from cobalt chrome-on-cobalt chrome, cobalt chrome-on-polyethylene and stainless steel-on-polyethylene. Control synovial fluids were retrieved from primary arthroplasty cases with osteoarthritis. Synovial fluid was cultured with human primary fibroblasts for 48 hours in a cell culture system under standardised conditions. The “Comet” assay was used with an image analysis system to measure levels of DNA damage caused by the various synovial fluid samples.

Synovial fluids from cobalt chrome-on-cobalt chrome and cobalt chrome-on-polyethylene joint replacements both caused substantial levels of genetic damage as detected by the Comet assay. Synovial fluids retrieved from stainless steel-on-polyethylene joints caused low levels of damage. The difference between these groups was highly statistically significant (p< 0.001). Control synovial fluids from osteoarthritic joints caused minimal changes. Atomic absorption spectroscopy demonstrated that the metal-on-metal synovial fluids contained the highest levels of cobalt and chromium. Different alloys used in orthopaedic implants are associated with different levels of DNA damage to cultured human cells in vitro. We are able to demonstrate that this damage is attributable at least in part to the metal content of the synovial fluid samples. We have no evidence for any long-term health risk to patients with such implants.

Metal-on-metal bearing surfaces have been reintroduced for use in total hip replacement, despite concerns regarding the potential risks posed by metallic by-products. We have compared periprosthetic tissues from metal-on-metal and metal-on-polyethylene hip replacements at revision surgery with control tissues at primary arthroplasty.

Tissues were obtained from 9 control, 25 contemporary metal-on-metal, 9 CoCr-on-polyethylene and 10 titanium-on-polyethylene hip replacement arthroplasties. Each was processed for routine histology with Haematoxylin and Eosin. Quantitative stereological analysis was performed at the light microscopic level.

Metal-on-metal sections showed more surface ulceration and this was correlated with the density of inflammation in the deeper tissues layers. Metal-on-metal tissues displayed a pattern of well-demarcated tissue layers, which were rarely seen in metal-on-polyethylene cases. In metal-on-polyethylene cases, the inflammation was predominantly histiocytic. Metal-on-metal cases by contrast showed a lymphocytic infiltrate with abundant plasma cells. Metal-on-metal tissues showed a striking pattern of peri-vascular inflammation with prominent lymphocytic cuffs especially deep to areas of surface ulceration. Levels of inflammation were higher in cases revised for failure than in those retrieved at autopsy or exploratory surgery. Total replacement and surface replacement designs of metal-on-metal arthroplasty showed similar histological changes. Plasma cells were not seen in any of the metal-on-polyethylene cases. The differences between the patterns of inflammation and cellular infiltration seen in metal-on-metal and metal-on-polyethylene tissues were highly statistically significant.

The pattern and type of inflammation in periprosthetic tissues from metal-on-metal and metal-on-poly-ethylene arthroplasties is very different. Our findings support the conclusion that metal-on-metal articulations are capable of generating a form of immunological response to metallic wear debris that has not been described previously. The incidence and clinical implications of these immunological responses in failed metal-on-metal joints are unknown.

Purpose: The aim of this part retrospective and part prospective study was to establish the incidence of pinsite infections and assess evolution of changes in practice

Methods: Data was collected retrospectively and prospectively for pin site infections from the inception of limb reconstruction service viz. 1985 to January 2002. There were 812 patients, 1042 limb segments, and 9935 pins. The various external fixators used were limb reconstruction system (LRS) 549; Ilizarov 397; Sheffield ring fixator (SRF); Dynamic axial fixator (DAF) 35; LRS/Sequoia 8; LRS/Garche 7; and Pennig 5.

Results: The pin site infections were graded from 0 to 6 ( Saleh & Scott). There were no infections in 206 segments. The infection grade is shown below:

We changed our pin tract care practice from 1996. We had a significant decrease in pin tract infections since then (p< 0.0001). We also found that using Ilizarov wires had significantly less infections than with half pins used with monolateral fixators (p< 0.0001; linear trend, p= 0.0338). There were 48 patients that required hospital admissions for IV antibiotics. and of these 10 patients required debridement. There were no residual long lasting infections or chronic osteomyelitis.

Conclusion: Attention to detail in insertion of wires and half pins is crucial to avoid pin site infections. This audit supports the fact that external fixation is a safe method from the point of view of infection contrary to general belief.

Purpose: To identify the risk of metastases at the time of diagnosis in patients with soft tissue sarcomas and to estimate the cost effectiveness of identifying these.

Methods: A retrospective database review was used to identify all new soft tissue sarcoma patients referred to our unit and to find those identified to have metastases at diagnosis. Data of tumour size, depth, grade, age, type of tumours, Chest x-ray (CXR)/CT chest results were available in all patients. We estimated the efficacy of CXR in identifying metastases and the costs of various staging strategies.

Patients: 1170 with newly diagnosed STS in 7.5 years (1996–2004) were included.

Results: The incidence of metastases at diagnosis was 10% (116 patients), 8.25% (96 patients) had lung metastases and 20 had metastases elsewhere. The risk of having lung metastases at diagnosis was 11.8% in high grade tumours, 6.95% in intermediate grade and 1.2% in low grade tumours. The risk increased almost linearly with size at presentation and was higher in deep tumours and older patients. CXR alone detected 2/3 of all lung metastases. The positive predictive value of the CXR was 93.7%, the negative predictive value was 96.7%, the sensitivity 62.5% and the specificity 99.6%.

The accuracy was 96.9%. CT overestimated metastases in 4%.

Discussion: We recommend that all patients with a newly diagnosed STS should have a CXR and only those with an abnormality or who have large, deep high grade tumours should have a CT chest. This strategy will save £7500 per 100 new patients with STS and will detect 93% of all chest metastases, missing 1 patient with metastases per 166 patients.

Metal-on-metal joint replacements have been reintroduced despite some concerns regarding the potential risks posed by soluble metallic by-products. We have investigated whether there are metal selective differences between the levels of genetic damage caused to a human cell line when cultured with synovial fluids retrieved from orthopaedic joint replacement prostheses at the time of revision arthroplasty.

Methods: Synovial fluids were retrieved from revision hip and knee arthroplasty patients with bearings made from Cobalt chrome-on-Cobalt chrome, Cobalt chrome-on-polyethylene and Stainless Steel-on-polyethylene. Control synovial fluids were retrieved from primary arthroplasty cases with osteoarthritis and no implant in situ. Synovial fluid was cultured with human primary fibroblasts for 48 hours in a cell culture system under standardised conditions. The ‘Comet’ assay was used with an image analysis system to measure levels of DNA damage caused by the various synovial fluid samples. Metal levels were measured in the synovial fluid samples using atomic absorption spectroscopy.

Results: Synovial fluids from Cobalt Chrome-on-Cobalt Chrome and Cobalt Chrome-on-polyethylene joint replacements both caused substantial levels of genetic damage as detected by the Comet assay. Synovial fluids retrieved from Stainless Steel-on-polyethylene joints caused low levels of damage. The difference between these groups was highly statistically significant (p< 0.001). Control synovial fluids from osteoarthritic joints caused minimal changes. Atomic absorption spectroscopy demonstrated that the metal-on-metal synovial fluids contained substantially more cobalt and chromium than the fluids retrieved from cobalt chrome-on-polyethylene joints. Stainless steel-on-polyethylene synovial fluids contained the least metal.

Conclusions: Different alloys used in Orthopaedic implants are associated with different levels of DNA damage to cultured human cells in vitro. We are able to demonstrate that this damage is attributable at least in part to the metal content of the synovial fluid samples. We have no evidence for any long-term health risk to patients with such implants. Further research is needed in this field.

Aims: Irradiated allograft bone may help to reduce the risk of transmission of infectious agents from donor to recipient. The purpose of this study was to establish the results of impaction bone grafting of acetabular defects with froze, irradiated allograft bone. Methods: All patients treated by a single surgeon with impaction bone grafting of acetabular defects at revision total hip replacement were reviewed retrospectively. All operations were performed during the period 1994–2000. The mean follow-up was 50 months (range 30–96 months). Case notes and X rays were reviewed and analysed. The Paprosky grade of acetabular defects was determined from the pre-operative X rays and the surgeonñs operation note. Post-operative X rays were reviewed to establish the extent and rate of new bone in-growth. Functional outcomes were determined by way of self-administered questionnaires. Results: Complete records and X rays were obtained for 33 patients who underwent revision hip arthroplasty with impaction bone grafting of the acetabulum using frozen, irradiated allograft bone. There were no complications associated with the bone grafts and no patient required a re-operation. Review of serial X rays conþrmed in-growth of host bone and the functional outcome was satisfactory. Overall 29 patients (88%) declared themselves satis-þed with the outcome of their operation and 32 patients (97%) improved functionally after the operation. Conclusions: These results indicate that satisfactory results can be achieved with impaction bone grafting using frozen, irradiated allograft bone. The use of irradiated bone graft can potentially reduce the risk of disease transmission from donor to recipient without compromising the surgical results.

Irradiated allograft bone may help to reduce the risk of transmission of infectious agents from donor to recipient. The purpose of this study was to establish the results of impaction bone grafting of acetabular defects using irradiated allograft bone.

Patients treated with impaction bone grafting of ace-tabular defects between 1994 and 2000 were reviewed retrospectively. The mean follow-up was 50months (range 30–96months). Case notes and Xrays were reviewed and analysed. The Paprosky grade of acetabular defects was determined. Functional outcomes were determined by way of self-administered questionnaires.

Complete records and Xrays were obtained for 33 patients who underwent impaction bone grafting of the acetabulum using freeze-dried, irradiated bone. The Paprosky classifications of the defects were as follows: 3 type 1, 10 type 2A, 4 type 2B, 4 type 2C, 10 type 3A and 2 type 3B.

There were no complications associated with the bone grafts and no patient required reoperation. Review of serial Xrays confirmed ingrowth of host bone. The functional results obtained were as follows: 17 patients (52%) could walk an unlimited distance. 11 patients (33%) required no walking aids whilst a further 17 (52%) required a single cane to mobilise. 21 patients (64%) were able to use public transport after the operation. 20 patients (61%) reported little or no pain. 9 patients (28%) had no limp and 14 patients (42%) had a slight limp. Overall 29 patients (88%) declared themselves to be satisfied with the outcome of their surgery. 32 patients (97%) improved functionally after their operation.

These results indicate that satisfactory results can be achieved with impaction bone grafting using irradiated, frozen allograft bone. The use of irradiated bone graft can potentially reduce the risks of disease transmission from donor to recipient without compromising the surgical results.

Anterior knee pain attributable to the patellofemoral joint and extensor mechanism dysplasia is a common presentation to Orthopaedic surgeons. Plain radiology is likely to remain the primary investigation of the knee in most centres, but most of the radiological features of extensor mechanism dysplasia are time consuming and difficult to measure reproducibly. 137 consecutive symptomatic knees aged under 30, referred to an Orthopaedic surgeon were studied in order to identify a rapid and reproducible marker for those knees worthy of further in-depth analysis.

Overall, 67 knees (49%) had at least one radiological abnormality and 70 (51%) were considered ‘normal’. There were 5 Dejour Type3 dysplasias of the femoral trochlea, 9 Type2 and 12 Type1. There were 49 cases of patella alta and 5 of patella infera. Four knees had an abnormal lateral patellofemoral (patellar tilt) angle. 15 knees had more than one abnormality. The classification of trochlear dysplasia was difficult and showed poor reproducibility. This was also true for the measurement of lateral patellofemoral angles. Patellar height was more easily measured but took time. The sulcus angle emerged as an easily and rapidly measurable feature that was reproducible and was closely related to the other features of extensor mechanism dysplasia.

The sulcus angle offers a rapid and reliable ‘screening’ measurement on knee radiographs. A normal sulcus angle suggests that seeking the other radiological markers of extensor mechanism malalignment is unlikely to reveal additional useful information. Other diagnoses can then be sought. The more abnormal the sulcus angle, the more severe the other features of extensor mechanism dysplasia are likely to be. Further detailed measurements can then help to define the most appropriate surgical correction.

A prospective clinical investigation to determine the optimum knee flexion angle for the ‘skyline’ patellofemoral joint radiograph.

Plain radiography of the patello-femoral joint includes the axial or ‘skyline’ radiograph. The optimum knee flexion angle for making this image remains unclear.

We therefore performed a prospective clinical study in which patients underwent three skyline radiographs with knee flexion angles of 30(or minimal flexion), 50 and 90 degrees. The patients were new patients, aged between 12 and 30, presenting to a knee clinic with anterior knee pain. Two observers evaluated the radiographs, making a standardised series of measurements. Blinding was organised so that the observers were unable to use any information other than the radiographic image alone. One observer evaluated all the films on two separate occasions to allow calculation of intra- and interassessor agreement.

There were 67 knees from 46 patients. There was a high level of intra- and inter-observer agreement. There were a number of patients in which the radiographic appearance of the patello-femoral varied markedly between the different views; in all cases the abnormality was best demonstrated by the 30-degree view. There were however a number of minimal flexion views in which the film contained incomplete information because part of the patello-femoral joint was missing from the image.

We conclude that whilst a minimal flexion skyline view is the most sensitive method for the detection of patellar tilt and subluxation, not all knees can be successfully imaged at the required position. A flexible approach is therefore needed, to obtain satisfactory images at minimal flexion.

A total of 90 patients with an isolated rupture of the anterior cruciate ligament (ACL) had a reconstruction using the ipsilateral patellar tendon secured with round-headed cannulated interference screws. Annual review for five years showed three failures of the graft (two traumatic and one atraumatic); none occurred after two years. Ten patients sustained a rupture of the contralateral ACL. At five years, 69% of those with surviving grafts continued to participate in moderate to strenuous activity. Using the International Knee Documentation Committee assessment, 90% reported their knee as being normal or nearly normal and had a median Lysholm knee score of 96 (64 to 100). Most patients (98%) had a pivot shift of grade 0 with the remaining 2% being grade 1; 90% of the group had a Lachman test of grade 0. The incidence of subsequent meniscectomy was similar in the reconstructed joint to that in the contralateral knee. Radiological examination was normal in 63 of 65 patients. Our study supports the view that reconstruction of the ACL is a reliable technique allowing full rehabilitation of the previously injured knee. In the presence of normal menisci there is a low incidence of osteoarthritic change despite continued participation in sporting activity.

Skeletal muscle grafts, when thawed after freezing, can be used to repair peripheral nerves. This method was used after transection of the median nerve in the upper arm in marmosets. Examination at 28 days showed total denervation of flexor carpi radialis; at 150 days electrophysiological evidence of recovery of nerve conduction across the graft and of muscle activation was seen. Sections at this time showed nerve fibres and new functional neuromuscular junctions in the muscle. It is concluded that effective reinnervation of target muscles is possible after peripheral nerve repair using skeletal muscle autografts.