Abstract

The current study aims to ascertain the outcome of ACI with simultaneous transplantation of an autologous bone plug for the restoration of osteoarticular defects in the femoral condyle of the knee (‘Osplug’ technique).

Seventeen patients (mean age of 27±7 years), twelve with Osteochondritis dissecans (OD) and five with an osteochondral defect (OCD) was treated with unicortical autologous bone graft combined with ACI (‘Osplug’ technique). Functional outcome was assessed with Lysholm scores obtained for 5 years post-operatively. The repair site was evaluated with the Oswestry Arthroscopy Score (OAS), MOCART MRI score and ICRS II histology score.

The mean defect size was 4.5±2.6 SD cm² and mean depth was 11.3±5 SD mm. A significant improvement of Lysholm score from 45 (IQR 24, range 16–79) to 77 (IQR 28, range 41–100) at 1 year (p-value 0.001) and 70 (IQR 35, range 33–91) at 5 years (p-value 0.009). The mean OAS of the repair site was 6.2 (range 0–9) at a mean of 1.3 years. The mean MOCART score was 61 ± 22SD (range 20–85) at 2.6 ± 1.8SD years. Histology demonstrated generally good integration of the repair cartilage with the underlying bone. Poor lateral integration of the bone graft on MRI and low OAS were significantly associated with a poor outcome and failure.

The Osplug technique shows significant improvement of functional outcome for up to 5 years. This is the first report describing the association of bone graft integration with functional outcome after such a procedure.

Summary

Randomised controlled study evaluating new bone formation in vivo in fracture non-unions by bone marrow derived stromal cells (BMSC). These cells do not show statistically significant new bone formation. Age of the patient during fracture, diabetes and doubling time had been observed to be correlated with fracture healing.

Aim

To evaluate the efficacy of bone marrow derived stromal cells (BMSC) for the treatment of non-unions in fractures.

Introduction

Meniscus deficiency leads to the development of early arthritis. Total knee replacement may be the only available treatment option in certain situations. However it is generally best avoided in young patients. We hypothesized that a combination of the two procedures, Allograft Meniscal Transplantation (AMT) and Autologous Chondrocyte Implantation (ACI) would be a solution to treat bone-on-bone arthritis in meniscal deficient knees and postpone the need for a total knee replacement (TKR).

Introduction

Regenerative medicine is a rapidly expanding discipline. However due to a lack of validated outcome measures, clinical trials have been far few. This study aims to assess the validity, inter-observer reliability and intra-observer reproducibility of experimental fracture healing assessment on plain radiographies. This technique involves implantation of mesenchymal stem cell (MSC) seeded constructs on only one side of the fracture after randomisation.

Background

Autologous Chondrocyte Implantation (ACI) is frequently used to treat chondral defects in the knee with a good long-term outcome. This is contraindicatd in meniscal deficient knees. Allogenic Menicsal Transplantation (AMT) has been shown to give good symptomatic relief in meniscus deficient knees. However this is contraindicated in advanced cartilage degeneration. We hypothesized that combination of these two might be a solution for bone-on-bone arthritis in young individuals.

Background

Thrust plate prosthesis (TPP) is a bone conserving prosthesis in use for over thirty years. TPP is a stemless and uncemented femoral prosthesis fixed at the lateral femoral cortex with a bolt, plate and screw. This has a metal-on-metal articulation with a 28mm Metasul head and Allofit press fit acetabular cup. Our study aimed to assess the functional outcome of this prosthesis.

Background

Autologous Chondrocyte Implantation (ACI) is a procedure which is gaining acceptance for the treatment of cartilage defects in the knee with good results and a long term durable outcome. Its use in other joints has been limited, mainly to the ankle. We aimed to assess the outcome of ACI in the treatment of chondral and osteochondral defects in the hip.

Background

Hip resurfacing has resurged in the last decade due to a renewed interest in metal on metal bearing. One of the proposed advantages is ease of revision of the femoral component. Short term functional results after femoral revision are similar to those after conventional total hip replacement. Survival and function after revision of the acetabular component only or of both components have not been reported. We aimed to assess hip function and implant survival after revision of the acetabular component for failed Birmingham hip resurfacing (BHR).

Thrust plate prosthesis (TPP) is a bone conserving prosthesis in use for over thirty years. TPP is a stemless and uncemented femoral prosthesis fixed at the lateral femoral cortex with a bolt, plate and screw. This has a metal-on-metal articulation with a 28mm Metasul head and Allofit press fit acetabular cup. Our study aimed to assess the survival of this prosthesis. At Oswestry 234 TTP's were implanted between 1995 and 2005. All patients completed a self-assessed questionnaire of Harris Hip Score pre-operatively and post-operatively at 2 months, 1 year, and then yearly. Only those who had a follow up was within the last two years were included in the analysis. 76 patients who had failed to satisfy the criteria were excluded. Of the 158 hips in the study 75 hips were in male patients and 83 were in female patients. The median age of patients was 52 years (range 15 to 82). 75 hips were on the right side and 83 on the left. All patients were operated by the senior author or a senior trainee under his supervision (seven hips). Revision of the implant or decision to revise was taken as the end point of our study. The median time to follow up was 7 years (range 1 to 15). The median pre-operative hip score was 43 (range 3 to 77) which rose to 83 points (range 11 to 100) at the latest follow up. Median hip score in females improved from 39 to 82 points and in males from 52 to 85 points. Twelve patients (5.1%) underwent revision surgery either for infection or aseptic loosening. The Thrust Plate Prosthesis had a good outcome with an increase in hip score of 40 points and 94.9 % survival at a median of 7 years.

A new surgical hybrid technique involving the combination of autologous bone plug(s) and autologous chondrocyte implantation (AOsP-ACI) was used and evaluated as a treatment option in 15 patients for repair of large osteochondral defects in knee (N=12) and hip joints (N=3). Autologous Osplugs were used to contour the articular surface and the autologous chondrocytes were injected underneath a biological membrane covering the plug. The average size of the osteochondral defects treated was 4.5cm². The average depth of the bone defect was 26mm. The patients had a significant improvement in their clinical symptoms at 12 months with significant increase in the Lysholm Score and Harris Hip Score (p = 0.031). The repaired tissue was evaluated using Magnetic Resonance Imaging, Computerised Tomography, arthroscopy, histology and immunohistochemistry (for expression of type I and II collagen). Magnetic Resonance Imaging, Computerised Tomography and histology at 12 months revealed that the bone plug became well integrated with the host bone and repair cartilage. Arthroscopic examination at 12 months revealed good lateral integration of the AOsP-ACI with the surrounding cartilage. Immunohistochemistry revealed mixed fibro-hyaline cartilage. We conclude that the hybrid AOsP-ACI technique provides a promising surgical approach for the treatment of patients with large osteochondral defects. This study highlights the use of this procedure in two different weightbearing joints and demonstrates good early results which are encouraging. The long term results need to be evaluated.

Hip resurfacing with metal-on-metal in patients with osteonecrosis (ON) raises concerns of early failure. This study addresses the hypothesis that osteonecrosis as a pre-operative diagnosis significantly increases the risk of failure following hip resurfacing. We analyzed data of 202 hips that underwent metal-on-metal hip resurfacing. In group 1 were 101 hips with a pre-operative diagnosis of osteonecrosis. In group 2 were 101 hips with other pre-operative diagnosis of osteoarthritis. Survival analysis with Cox regression was used to compare the revision risks of both groups. The mean age at operation was 42 years in osteonecrotic and 43 years in osteoarthritic group. The preoperative and postoperative hip scores were 62 and 96 for osteonecrotic group and 58 and 95 for osteoarthritic group, respectively. Survival analysis with revision for any reason as the endpoint was performed on the two groups which had identical follow-up periods. Survival at 10 years was 97.7% for osteonecrosis and 95.0% for osteoarthritis. The revision risk for patients with osteonecrosis was lower (0.37, 95% CI 0.07 – 1.82, Cox regression) but the difference was not significant (p = 0.19). Our study found no difference in revision risk in patients with osteonecrosis as compared to those with osteoarthritis

We aimed to assess the long term results of patients who underwent Autologous Chondrocyte Implantation (ACI) for osteochondral lesions of the talus. Between 1998 and 2006, 28 patients underwent ACI for osteochondral lesions of the talus. All these patients were prospectively reviewed and assessed for long term results. Outcomes were assessed using satisfaction scores, Mazur ankle score and the AOFAS score, and Lysholm knee score for donor site morbidity.

The 28 patients who underwent the procedure included 18 males and 10 females. Follow up ranged from 1–9 years. In all patients, there was an improvement in the Mazur and AOFAS ankle scores and the Lysholm scores showed minimal donor site morbidity. Improvement in ankle score was independent of age and gender. The better the pre-op score the less the difference in post-op ankle scores. Patients were unlikely to benefit with pre-op ankle scores over 75.

The mid to long term results of ACIs in the treatment of localised, contained cartilage defects of the talus are encouraging and prove that it is a satisfactory treatment modality for symptomatic osteochondral lesions of the talus. Complications are limited. However, in view of limited number of patients, a multi-centre randomised controlled study is required for further assessment.

Thirty-five patients were followed prospectively from their referral to the Problem Fracture Service with chronic osteomyelitis of diaphyseal bone between November 1994 and June 1999.

The patients were treated using a closed double-lumen suction irrigation system following reaming and arthroscopic debridement of the intramedullary canal; this is a modified system based on the work of Charles Lautenbach. Results of these procedures were regularly followed up in clinic, and between June and July 2007 the whole cohort was reviewed via postal questionnaire, telephone and case note review.

At a mean follow up of 101 months, 26 were living with no evidence of recurrence, 4 had died of unrelated causes with no evidence of recurrent infection. Four patients had persisting problems with sinus discharge requiring intermittent antibiotic therapy and 1 patient had his limb amputated for recurrent metaplastic change.

These results gave this cohort an 86% clearance of infection, with recurrence in 12%, which is comparable to the Papineau and Belfast techniques with significantly less surgical insult to the patient.

Conversion of failed femoral components of total hip resurfacing to conventional hip replacement is reportedly a straightforward procedure. There is little published to qualify this and what is available suffers from small study numbers and various combinations pre and post-operative implants.

Between 1997 and 2002, the Oswestry Outcome Centre prospectively collected data on 5000 Birmingham Hip Resurfacings (BHRs) performed by 141 surgeons, at 87 hospitals. To date 4526 have survived, 135 died and 165 are lost to follow-up. 174 have been revised, of which 60 were failures of the femoral component. We reviewed modes of failure and post-revision clinical outcomes in this sub-group.

Isolated femoral component failure accounted for 60 hips (1.2%). 28 femoral neck fractures, 14 femoral head collapses, 13 femoral component loosenings, 3 avascular necroses (AVN), 1 femoral loosening followed by fracture and 1 dislocation. Mean time to revision surgery was 2.6 years (1.8 years for neck fracture; 3.4 years femoral loosening, head collapse and AVN). All acetabular components were left in situ. At revision surgery 25 cemented, 25 uncemented and 10 unknown femoral prostheses were used with 56 BHR modular heads, 2 custom-made Exeter heads and 2 Thrust Plate heads. 47 patients completed outcome scores post-revision surgery. Median modified Harris Hip Score was 82 (IQ range=63–93) and Merle d’Aubigne score was 14 (IQ= 9.5–15) at a mean follow up of 3.9 years post-revision. The 4526 surviving resurfacings had a median hip score of 96 (IQ=87–100) p≤4.558x10-8 and median Merle score of 17 (IQ=14–18) p≤1.827x10-7. Mean 7.0 years follow up. There was no difference in outcomes between cemented and un-cemented revision components nor were there differences between fractured neck of femur and femoral loosening, head collapse or AVN.

Following revision of the femoral component to a conventional hip replacement, function is significantly worse than surviving resurfacings.

Introduction: Autologous chondrocyte implantation (ACI) has been used most commonly as a treatment for cartilage defects in the knee and there are few studies of its use in other joints. There is only one published report of its use in the hip. Is there a role for ACI of the hip?

Materials and Methods: We describe fourteen consecutive patients studied prospectively with chondral or osteochondral lesions of the femoral head that underwent ACI and were prospectively reviewed with a follow up of 5 years (mean 30 months).

Three patients presented with Perthes and five with AVN. Four had chondral loss following trauma and one presented with an area of bone loss in a hip with congenital dysplasia. Defect size was a mean 6.2 cm2.

Pre-operatively hip function was assessed by the patient using the Harris Hip Score and MRI. Postoperatively these were repeated at 1 year and hip scores repeated annually.

Hip arthroscopy and cartilage biopsy provided Cells for culture in a GMP laboratory where passage numbers were limited to two. Three weeks later by open surgery, all unstable cartilage was excised, the base was debrided or excised and bone graft applied, and suture of a membrane of periosteum or collagen membrane over the defect undertaken. A mean 5.2 million chon-drocytes were inserted beneath this patch following a test of the seal.

Results: Ten of the fourteen patients improved at one year, with a mean rise in Harris Hip score from 57 to 63 points. Five patients underwent arthroscopic examination at one year and in four there was evidence of good integration of the new cartilage. In one patient arthros-copy was difficult due to previous trauma. One patient developed AVN as a post-operative complication following a posterior approach. Four patients have progressed to hip replacement or resurfacing but it is of note that all these patients had cyst formation pre-operatively.

Conclusion: The short-term results of ACI for osteo-chondral lesions of the hip suggest that if good early results are obtained they are observed to continue out to 5 years. There is a high failure rate in those with pre-operative cyst formation in the hip

Introduction: Conversion of failed femoral components of total hip resurfacing to conventional hip replacement is reportedly a straightforward procedure. There is little published to qualify this and what is available suffers from small study numbers and various combinations pre and post-operative implants.

Method: Between 1997 and 2002, the Oswestry Outcome Centre prospectively collected data on 5000 Birmingham Hip Resurfacings (BHRs) performed by 141 surgeons, at 87 hospitals. To date 4526 have survived, 135 died and 165 are lost to follow-up.

174 have been revised, of which 60 were failures of the femoral component.

We reviewed modes of failure and post-revision clinical outcomes in this sub-group.

Results: Isolated femoral component failure accounted for 60 hips (1.2%). 28 femoral neck fractures, 14 femoral head collapses, 13 femoral component loosenings, 3 avascular necroses (AVN), 1 femoral loosening followed by fracture and 1 dislocation. Mean time to revision surgery was 2.6years (1.8years for neck fracture; 3.4years femoral loosening, head collapse and AVN).

All acetabular components were left in situ. At revision surgery 25 cemented, 25 uncemented and 10 unknown femoral prostheses were used with 56 BHR modular heads, 2 custom-made Exeter heads and 2 Thrust Plate heads.

47 patients completed outcome scores post-revision surgery. Median modified Harris Hip Score was 82 (IQ range=63–93) and Merle d’Aubigne score was 14 (IQ= 9.5–15) at a mean follow up of 3.9years post-revision.

The 4526 surviving resurfacings had a median hip score of 96 (IQ=87–100) p≥4.558x10-8 and median Merle score of 17 (IQ=14–18) p≥1.827x10-7. Mean 7.0 years follow up.

There was no difference in outcomes between cemented and uncemented revision components nor were there differences between fractured neck of femur and femoral loosening, head collapse or AVN.

Discussion: Following revision of the femoral component to a conventional hip replacement, function is significantly worse than surviving resurfacings.

Introduction: Hip resurfacing is a renaissance of metal on metal hip arthroplasty. It preserves bone stock and a large head allows greater range of motion. This new technique is gaining popularity among patients and surgeons alike. We present a nine year follow up in the context of survival, function and complications.

Methods: We analysed follow up data of 4778 patients who have had hip resurfacing using Birmingham Hip resurfacing (Smith & Nephew, UK) in 37 countries. Patients were followed up annually using Oswestry hip score and any revisions were updated on the database at the Oswestry Outcome Centre. Function was analysed using multilevel modelling and Kaplan-Meier method used for survival analysis.

Results: There were 3193 males and 1585 females operated by 138 surgeons in 37 countries. The mean age was 52.8 years (13 – 87.8). Using hierarchical regression the annual hip scores were analysed. Overall function was significantly affected by pre op score and gender (p< 0.01). Age at operation had no effect on outcome score (p =.462).

We observed similar effect in individual domains of pain, mobility and range of motion. Survival of the implant at nine years with revision due to any reason was 93.5%. We observed a significant difference in survival of procedures done by pioneer surgeons and by non pioneering surgeons (p < 0.01) (log rank test). There were 119 complications of which there were 30 fractures, 21 occurring within the first six months of operation.

Conclusion: Nine year results of hip resurfacing arthroplasty look promising and are comparable to traditional hip arthroplasty. The difference between two surgeon groups could be due to a learning curve in the technique. Further follow up would be necessary to ascertain the long-term clinical effectiveness of this technique.

Introduction: Total hip replacement in one of the most commonly performed operation in orthopaedics in the UK with similar numbers being operated in other parts of the world (2). The main reasons for this magnitude are marked improvement in function and the quality of life. The hip prosthesis has evolved significantly over half a century and better prostheses are available today. These newer implants are required to have a survival of 90% for a minimum of 10 years. The improved survival of the implant tends to have effect on the quality of life as well as the life expectancy. There has been a continuous attempt to quantify this increased life expectancy and survival following total hip arthroplasty.

Materials and Methods: We compared the mortality figures of 3947 patients who had hip resurfacing arthroplasty with the national mortality figures of the UK. The cause of death was determined by telephone call to the next of kin and from the national death register.

Results: The average standardized mortality ratio of hip resurfacing patients compared to national figures over the nine year period was 0.524(99 percent C.I. 0.39 to 0.69). Individual SMR for each year is shown in Table. The number of observed deaths were 86 as compared to the expected deaths number 164. Out of the total 86 deaths over a nine year period, 36 deaths were due to cancer, 25 due to cardiovascular causes, eight due to respiratory conditions, four following accidents and 13 due to other causes such as suicide, old age. In the cancer group 7 patients died of lung cancer and 8 died of blood cell neoplasms. National figures for year 2007 were not yet compiled so SIR for cancer was not calculated.

Conclusion: The results of this study are comparable to other follow up studies on mortality following total hip replacement. This indicates that increased activity following hip resurfacing may help the patients maintain better fitness.

The incidence of cancer needs to be interpreted with caution and can only be ascertained by a prospective study.

Objective: Assessment of hip function is done by surgeon and few patient based tools. These patient assessed scores do not measure range of motion. The American Academy of Orthopaedic Surgeons has outlined pain, mobility and range of motion as three fundamental aspects of joint assessment. We aimed to validate Oswestry hip score which was developed as a patient-completed self-assessment to provide both Harris hip score and Merle d’Aubigne hip score with added content to estimate hip range of motion.

Methods: 144 patients completed the Oswestry hip score, WOMAC Index and the Oxford hip score at two different occasions. The patients were seen two weeks later and filled the Oswestry hip score and a surgeon filled the Harris hip score. The study included 80 females and 64 males with a mean age of 62 years range (32–91). We assessed the reliability, validity and responsiveness of this new tool by comparing the individual domains of the Oswestry hip score to similar domains of the WOMAC, Harris hip score and Oxford hip score.

Results: The reliability of this new score was established by the Intraclass Correlation Coefficient. Internal consistency was measured by Cronbach’s alpha. The Cronbach’s alpha was 0.7, which is considered a good measure of internal consistency. Content validity of the Oswestry hip score was established by the validated domains of pain, function and range of motion of the Harris hip score. Analysis of frequency of response distribution showed normal floor and ceiling effect for any of the domains of the Oswestry hip score. Multi-method multitrait matrix analysis was used to establish the construct validity of the Oswestry hip score. There was good correlation between pain and function domains (p< 0.001). Moderate correlation was found among clinical assessment of hip movement and movement domains of Oswestry hip score (Pearson’s r=0.55; p0.001). The responsiveness of the Oswestry hip score was measured with Cohen’s effect size. An effect size of > 0.8 is considered large. The mean effect size was 2.06 (1.36–2.97).

Conclusion: A positive construct validity and high correlation with WOMAC, Oxford Hip Score and Harris hip score shows that the Oswestry hip score can give an adequate measure of hip joint function. An effect size of 2.0 shows good responsiveness of the Oswestry hip score. The Oswestry hip score can be completed by patients themselves and is therefore ideal for long-term and large scale collection of clinical outcome data.

Non-union is poorly understood. It is unknown if multipotent cells are present in non-union tissue or whether the activity of such cells is dysfunctional. Clinically, this is important as it may predict the success of novel therapies such as BMP treatments and cell-transplantation. This study aimed to study the characteristics of cell types present in human fracture non-union tissue, in comparison with bone marrow stromal cells (BMSC) from the patient and other healthy patients.

Non-union tissue was harvested (n=8) from long bones. Cells were isolated enzymatically and cultured in monolayer. BMSC were isolated by density gradient centrifugation of iliac crest biopsies. Their phenotype was assessed by FACS analysis for CD34, 45 and 105 markers. Their comparative growth kinetics was examined, as was their osteogenic and adipogenic capacity following extended culture in defined medium. Cell differentiation status was evaluated using alkaline phosphatase, von Kossa and oil-red O staining. Cell senescence was assessed via cell morphology, senescence associated Beta-galactosidase (SA-Beta)-Gal) activity.

Non-union cells grew in monolayer, but showed different morphologies; many non-union cells contained stress filaments (typical of senescent cells) or were of stellate appearance. In addition, significantly more non-union cells were positive for SA-Beta-Gal activity compared to BMSC (P=0.0006). Growth kinetics showed longer doubling times for cells isolated from non-union tissue when compared to BMSC isolated from the patient. Long term culture of non-union cells showed early growth arrest at passages 3–8. FACS analysis showed isolated cells to be CD34/45 negative and CD105 positive. Both non-union cells and BMSC differentiated along osteogenic and adipogenic lineages to varying extents.

Our novel results show that cells from non-union tissue exhibit senescence in culture. Hence, cell senescence is potentially involved in the aetiopathogenesis of non-unions. Whether or not this senescence has arisen through cell division (during failed repair attempts) or via abnormal biomechanical loading warrants further study. The influence of senescent cells on the healing process also requires investigation. Clearly these cells are able to differentiate into osteoblasts in vitro but may have an aberrant influence on union in vivo.

Objective: The aim of this study was to validate Oswestry hip score. This is a new score which was developed as a patient completed self-assessment to provide both Harris and Merle d’Aubigne hip score with added content to estimate hip range of motion.

Methods: 61 patients completed the Oswestry hip score, the WOMAC and the SF-36. Validity was tested by comparing the domains and items of the Oswestry hip score to WOMAC and SF-36. The new movement scale of Oswestry hip score was specifically validated against Merle d’ Aubinge, mobility scoring system. SPSS software was used for statistical analysis.

Results: Mean age was 56 years (range 18–83).Content validity of the Oswestry hip score was demonstrated by two main indicators for hip surgery, pain and function. Analysis of frequency of response distribution showed no floor or ceiling effect for any of the domains of the Oswestry hip score. Construct validity of the Oswestry hip score domains of pain and function showed good correlation with the correspondent domains of WOMAC and SF-36 (p< 0.001). Moderate correlation was found among clinical assessment of hip movement, Merle d’ Aubinge mobility score and movement domains of Oswestry hip score (Pearson’s r=0.55; p0.001). Correlation between Harris and Oswestry hip score was 0.63 to 0.91. Cronbach’s alpha was 0.7, showing good internal consistency.

Conclusion: A positive construct validity and high correlation with WOMAC and SF-36 shows that the Oswestry hip score is can give an adequate measure of hip joint function. The new questionnaire is brief and can be completed by patients themselves. It is therefore ideal for long-term and large-scale collection of data. Oswestry hip score does not intend to replace the clinical examination at the critical phases following hip surgery but can be a useful adjunct. We report the validity and reliability of this new tool.

Introduction: Monoclonal antibodies (mAbs) recognizing linear sulphation motifs in keratan sulphate (KS) were first developed in the early 1980’s. Over the years, ELISAs using 5-D-4 or other related anti-KS mAbs have been used in many studies monitoring increased cartilage aggrecan degradation with the onset of degenerative joint diseases. However, whilst these studies have in general been useful for monitoring some aspects of disease progression (usually in parallel with other biomarker assays), many longitudinal studies have shown efficacy in only the transient (early, mid or late) stages of the degenerative joint disease process. During the onset of degenerative joint disease, the pathological tissue attempts to repair/regenerate the cartilage, the chondrocytes thus synthesizing cartilage aggrecan with KS substitution [and chondroitin sulphate (CS) isomer composition] that is more like that found in developing or immature cartilage. This immature cartilage aggrecan contains much less KS substitution with shorter chain size and less linear sulphation motifs. Thus, during the different stages of degenerative joint disease progression one would expect to find variable changes in different linear sulphation epitopes present in the serum or synovial fluids. The aim of this study was to investigate the use of several monoclonal antibodies that recognise different sulphation epitopes [high sulphation (5-D-4), low sulphation (1-B-4) and KS-stubs (BKS-1)] to see if patterns of their expression could be used to distinguish different stages of degenerative joint disease. We have also developed ELISAs using mAbs recognising the KS-proteoglycans, keratocan (Ker 1) and lumican (Lum 1) for their quantification as potential biomarkers of osteoarthritis.

Methods: Competitive ELISAs were developed using monoclonal antibodies (mAbs) 5-D-4, 1B4, BKS-1, Ker-1 and Lum-1. Bovine corneal KS-proteoglycans pre-treated with keratanase were used as both the coating antigen and “standard” antigen on the same ELISA plate. Blood, synovial fluid and cartilage samples (surgical waste) obtained from patients undergoing arthroplasty with different Kellgren & Lawrence grades were analysed.

Results and Discussion: 5-D-4 and BKS-1 showed similar inhibition curves and relative 50% inhibition points. However, the curve obtained with 1B4 indicated lower relative expression of 1B4 epitope. Analysis of serum and synovial fluid sample with 5-D-4 mAb showed the presence of the epitope in both samples, but there was significantly less KS in serum than in the synovial fluid. Our results show that competitive ELISA for quantification of several different KS sulphation or “stub” epitopes and two KS-proteoglycans can all be quantified and compared using the same experimental conditions. These studies are ongoing as part of an Arthritis Research Campaign (UK) funded study. In addition the data indicates that keratocan and lumican are also increased in their expression with the progression of disease. Future studies will be performed in an attempt to quantify increased keratocan and lumican expression as potential biomarkers of degenerative joint disease.

Introduction: etiology of late infection after arthroplasty can be difficult to establish. Histology is the gold standard for infection in patients without inflammatory arthritis but diagnosis in inflammatory arthritis depends on culture (Atkins et al). Real-time PCR offers a rapid and direct assessment for staphylococci and enterococci infection but has not been widely assessed.

The aims of this study were

to develop the Roche lightcycler Staphylococcal and Enterococcal PCR kits to facilitate diagnosis of hip and knee prosthetic infections

Methods: uplicate, multiple tissue samples were taken (with separate sterile instruments) at the 1^st stage of revision after informed consent. One set were cultured and results interpreted by the Oxford criteria. The second set were extracted using the Qiagen DNA kit, purified (in-house method) and tested using the Roche lightcycler kits.

Results:53 patients undergoing 2 stage revision for suspected infection were recruited.15 (28.3%) had negative histology and no inflammatory arthritis; 3 with single positive cultures and negative PCR – considered contaminants.

29 patients had non-inflammatory arthritis. 14/18 (77.8%) with positive cultures had staphylococci +/or enterococci isolated and 10 PCR results correlated. The other 11 patients had negative cultures.

9 patients had inflammatory arthritis. Six were culture negative and of the other three, 2 were positive for staphylococci on culture with 1 positive by PCR.

Discussion: Negative staphylococcal PCR correlates with the isolation of staphylococci from only one sample. This agrees with the Oxford criteria that such samples may be considered contaminants. Additional positives detected by staphylococcal PCR alone are rare.

Enterococcal PCR confirmed culture positivity in 2/3 patients. An additional 5 positive PCR’s were obtained from patients’ culture negative for enterococci. It is not clear if these are false positives or more sensitive detection of enterococcal isolation.

Highly active anti-retroviral therapy has transformed HIV into a chronic disease with a long-term asymptomatic phase. As a result, emphasis is shifting to other effects of the virus, aside from immunosuppression and mortality. We have reviewed the current evidence for an association between HIV infection and poor fracture healing.

The increased prevalence of osteoporosis and fragility fractures in HIV patients is well recognised. The suggestion that this may be purely as a result of highly active anti-retroviral therapy has been largely rejected. Apart from directly impeding cellular function in bone remodelling, HIV infection is known to cause derangement in the levels of those cytokines involved in fracture healing (particularly tumour necrosis factor-α) and appears to impair the blood supply of bone.

Many other factors complicate this issue, including a reduced body mass index, suboptimal nutrition, the effects of anti-retroviral drugs and the avoidance of operative intervention because of high rates of wound infection. However, there are sound molecular and biochemical hypotheses for a direct relationship between HIV infection and impaired fracture healing, and the rewards for further knowledge in this area are extensive in terms of optimised fracture management, reduced patient morbidity and educated resource allocation. Further investigation in this area is overdue.

Introduction: The Trent arthroplasty register reported that results of Hip arthroplasty in general setup were less than that reported from specialist centres by 5%. This independent prospective study tests the hypothesis that results of Birmingham Hip Resurfacing arthroplasty from specialist centres would not accurately represent the outcome of hip resurfacing when performed in general setup.

Material and Methods: All patients were prospectively followed for at least five years at Oswestry Hip outcome centre. The surgeons carrying out the operation prospectively provided surgical details and thereafter patients were followed using Oswestry hip questionnaire (OSHIP) at fixed intervals. Survival was assessed by Kaplan-Meier method. The results were compared to the published results of BHR from specialist centers

Results: There were 679 patients, and 58 surgeons in the study. Mean age at operation was 51 years and mean follow up was 5.63 years. The predominant preoperative diagnosis was osteoarthritis. The mean OSHIP score was 89.5. There were 29 (4.2%) failures mostly due to fracture neck of femur (62%); all of them were revised to conventional THR. The Kaplan-Meier survival at seven years is 95.354%.

Discussion: Compared to the published results, there were 2 to 19 times high failure rate which is significantly higher (p=0.001) than the published studies. Hence we prove our hypothesis, as the results of BHR from specialist centres do not accurately reflect on the outcome in general setup. The discrepancy in the results that we have identified would help to identify the weak areas in the general setup, where most of the patients get benefited from BHR arthroplasty.

Introduction: The wear particles produced from the metal-on-metal hip prosthesis causes measurable rise of metal ion levels in the patient’s body fluids. Wear of the bearing is directly related to its use. The goal of this study is to test two hypotheses. Firstly, that exercise causes increased wear particles in vivo which can cause immediate measurable rise in the serum metal ion levels. Secondly, that this rise in metal ion level is different for different types of bearings.

Material and Methods: Eighteen participants were allocated to four different groups i.e. Birmingham Hip Resurfacing prosthesis group, Cormet 2000 resurfacing prosthesis group, Thrust plate prosthesis group (28mm metasul articulation) and group four with out any metal work. Blood samples were taken immediately before, immediately after and one hour after exercise. Plasma cobalt and chromium was determined using Inductively-Coupled-Plasma-Mass-Spectrometry and Dynamic-reaction-cell respectively with detection limit of 2nmol/l each.

Results: The four patient groups were comparable. A significant increase (p< 0.005) in serum cobalt and chromium of 13% and 11% respectively, was noticed after the exercise. Rise of cobalt levels in patients with a resurfacing MOM was 8.5 times (BHR group) and 6.5 times (Cormet group) larger than in those with a Metasul (p=0.021 and p=0.047). Neither rise of metal levels nor baseline levels correlated with any other factor (p> 0.27).

Discussion: Physiologic exercise causes immediate detectable rise in the serum metal ion levels. The increase is predominantly related to the size of the bearing surface. Exercise-related-cobalt-rise could be used to assess the tribology of the different metal on metal designs in vivo for future research

The Trent arthroplasty register reported that results of Hip arthroplasty in general setup were less than that reported from specialist centres by 5%. This independent prospective study tests the hypothesis that results of Birmingham Hip Resurfacing (BHR) arthroplasty from pioneering centres would not accurately represent the outcome of hip resurfacing when performed in general setup.

All patients were prospectively followed for at least five years at Oswestry Hip outcome centre. The surgeons carrying out the operation prospectively provided surgical details and thereafter patients were followed using Oswestry hip questionnaire (OSHIP) at fixed intervals. Survival was assessed by Kaplan-Meier method. Results were compared to the published results of BHR from specialist centres.

There were 679 patients, and 58 surgeons in the study. Mean age at operation was 51 years and mean follow up was 5.63 years. The predominant preopera-tive diagnosis was Osteoarthritis. Mean OSHIP score was 89.5. There were 29 (4.2%) failures mostly due to fracture neck of femur (34%). Out of 14 failures in the first year, 9 (64%) were due to fracture neck of femur. The Kaplan-Meier survival up to eight years is 95.354% in the current study.

Compared to the published results, there were 2 to 19 times high failure rate which is significantly higher (p=0.001) than the published studies. Most of the early failures were due to fracture neck of femur in the first year. Hence we prove our hypothesis, as the results of BHR from specialist centres do not accurately reflect on the outcome in general setup. The discrepancy in the results is mostly due to fracture neck of femur in the early postoperative time. The results of this study will enhance awareness of the early trend in failures. Appropriate patient selection and meticulous surgical technique will help avoid this complication in the general setup, where most of the patients get benefited from BHR arthroplasty.

In-vitro studies have shown that wear rates of the metal on metal (MOM) bearing hip prostheses decline once the bearing runs-in and the bearing subsequently enters a steady state wear phase. Baseline cobalt levels are thus expected to decline with time in patients. Several clinical studies have not found such a decline. Baseline cobalt levels are hence limited in their capacity to provide information on the wear performance of the bearing couple. We have demonstrated in a previous study that exercise causes a rise in plasma metal ion levels in patients with MOM bearing hip replacement. Would the exercise related cobalt rise be more sensitive to detect change in wear behaviour of the bearing couple? We tested the alternate hypothesis that exercise related rise in the plasma cobalt levels will correlate inversely with the duration of MOM implantation.

Sixteen patients with three different well functioning MOM bearing hip replacement [two types of resurfacing (BHR, Cormet) and Metasul] were included into the study. Patients were divided in to two groups based on time since implantation, an early group of mean 18 months and a late group of mean 57 months. Plasma levels of cobalt were measured before (baseline) and after 1 hour of maximal exercise (peak). The difference between baseline and peak for each patient provided the exercise related cobalt rise. A significant increase in plasma cobalt levels of 13% was noticed after the exercise (p < 0.005). Baseline Cobalt levels in the late group (53nmol/l) were higher than early group (44nmol/l) but the difference was not significant (p=0.45). However, the mean exercise related Cobalt rise levels was lower in late group (3.5nmol/l) than the early group (6.5nmol/l). This lower rise in cobalt level in the late group precisely reflects on the steady state wear as seen in in-vitro tests.

Baseline cobalt levels are limited in determining the in-vivo performance of the bearing couple. Exercise related rise in cobalt levels can differentiate the running in and steady state wear phases of metal on metal bearings and is thus a more accurate tool of assessing in-vivo wear performance of the bearing couple.

Introduction: Before proceeding to long-term studies, we studied early clinical results of combined Autologous Chondrocyte Implantation (ACI) and Allogenic Meniscus Transplantation (AMT). Meniscus deficient knees develop early osteo-arthritis (OA) of the knee joint. Autologous Cartilage Implantation (ACI) is contraindicated in case of meniscus deficient knees. And on contrary the Allogenic Meniscus Transplantation (AMT) is contraindicated in cartilage defects in the knee joint. But a combination of the two procedures for bone on bone OA might be a solution for this problem. This was the main purpose of our study.

Methods: We studied a consecutive series of eight patients (7 males and 1 female), with an average age= 43 years (29–58), presenting with painful secondary arthritis, due to premature loss of meniscus and chondral defect/s. Median size of the femoral defects was 8.16 cm2 and of the tibial side 2.69 cm2 All patients were treated with a combination of Autologous Chondrocyte implantation (ACI) and Allogenic Meniscus Transplantation (AMT). Chondral defects were covered with periosteum/ Chondroguide membrane, secured in place with in-vitro cultured autologous chondrocytes injected underneath the path. Meniscus placed as load-bearing washer on the surface of ACI of tibia. ACI rehabilitation protocol followed post-operatively. Assessment at the end of one year was done with self-assessed Lysholm score, histology and the MRI scan.

Results: Mean pre-operaive Lysholm score was 49 (17–75). This increased to a mean of 66 (26–87) at 1 year, an average increase of 16.4 points. Average one-year satisfaction score was 3 and they were back to all active life style. Five out of eight patients showed significant functional improvement at last post-operative follow-up (2 to 6 years; mean of 3.2 years). Complications were aseptic synovitis in 3 cases. Three failures were noted showig persistant pain and swelling in one, rupture of meniscus in second and third patient had a knee replacement. Arthroscopy at 1 year showed a stable meniscus with all healed peripheral margins in all except in one case with some thinning with no evidence of rejection. Histology of meniscus showed a fibrocartilage well populated with viable cells and the peripheral zone was well vascularised and integrated with capsule. Biopsy of ACI site was predominantly of fibrocartilage with good basal integration with subchondral bone. On MRI scan, allogenic meniscus was well integrated with capsule along the line of repair, showing foci of variable signal intensities within the meniscus. There was no evidence of meniscal subluxation in all but one case showing mild extrusion. ACI graft site showed a varied appearance, with 3 grafts showing focal grade 3to 4 changes.

Conclusion: Seven out of eight patients improved post-operatively at one year, in terms of pain relief and increased activity. It’s possible to combine these two techniques together. Short-term outcomes are satisfactory. We could not find any deleterious effects of combining these two techniques together. So we conclude that, this might act as a one step towards a biological knee replacement.

Background: Articular cartilage injuries are very common. Small defects don’t heal on their own and large defects can’t regenerate new cartilage. This would largely be due to the fact that chondrocytes are embedded in a firm and tough matrix and hence can’t migrate to the defect site to regenerate a new cartilage tissue. So ultimate fate is patient getting early osteoarthritis. Cartilage defects in the knee may be symptomatic and cause pain, swelling and catching. There are several different surgical procedures available to treat cartilage injuries, but no method has been judged superior. The ultimate aim of the treatment is restoration of normal knee function by regeneration of hyaline cartilage in the defect, and to achieve a complete integration to the surrounding cartilage and underlying bone. Arthroscopic debridement and lavage may give symptomatic relief for a limited time. Autologous Chondrocytes Implantation (ACI) was first described in 1994. Encouraging primary results were reported, and further research was promoted. Long-term results are encouraging. ACI is being done in Robert Jones & Agnes Hunt orthopaedic Hospital, Oswestry since last 8 years.

Methods: We studied a cohort of first 118 patients who underwent ACI for knee joint in this institute, focussing on their mid-term results. Patients having chondral defects were offered ACI. They all were explained the procedure and informed written consent was obtained. Patients filled in a self-assessed Lysholm forms before the operation. They also underwent pre-operative MRI scan of knee joint. ACI procedure consisted of three stages— Stage I —Arthroscopic harvest biopsy of cartilage and chondrocytes culture in lab. Stage II—Arthrotomy of the knee. The defect edges were freshened, covered by periosteum or chondroguide, which was sutured to the cartilage with 6-0 vicryl. Chondrocytes were injected underneath this patch. Post-op CPM and Physiotherapy. Stage III—1-year arthroscopic surgery. Assessment was done with Lysholm score, MRI scan, histological and arthroscopic analysis. Patients were followed up clinically thereafter with yearly Lysholm scores.

Results: 118 patients with an average age of 35 years (15–59) underwent ACI for knee in last 8 years. 93 patients had single defect, 24 had multiple (> 1) chondral defects, with mean area 4.81 cm2. MRI showed a good integration of defect with surrounding cartilage with varied signal intensities. About 55–56% patients underwent some or other form of trimming, which improved immediate results. However only 50 % of these were symptomatic. Defects on MFC did well as compared to other sites, followed by on trochlea. Defects on patella showed poor results, though the number is less for comparison. Total 79 specimens of 1-year histology showed good healing with formation of fibrocartilage (40), mixed (20) and hyaline (8), fibrous tissue (6), bone in 1 case and inconclusive in 2 cases. Mean pre-op Lysholm score was 50.16. Average score at one year was found to be 69.52.

Conclusion: Results of ACI are encouraging. Patients continued to improve slowly over a period of time, achieving maximum function between one and 2 years post-surgery. Our study showed that there after their scores remained static.

Introduction: Autologous Chondrocyte Implantation (ACI) was first described in 1994(1) and has become an increasingly widely used treatment for chondral defects in the knee. The intention of this study was to identify which patient and/or surgical factors affect clinical outcome. In order to do this, a multicentre database of patients treated with ACI was established.

Methods: Four European centres collaborating in the EuroCell project (2) contributed data. These centres have historically used different outcome measures to follow up their patients. In order to analyse this data, a method of z-transformation was used to standardise the clinical scores. This has allowed a large number of patients to be investigated even when different scores have been used. A panel of predictor variables was agreed relating to patient factors and operative technique. Linear multiple regression analysis was performed to determine which predictor variables significantly influenced clinical outcome.

Results: A total of 284 patient datasets from four centres were investigated with 1 to 10 year follow-up. In 213 datasets the Modified Cincinnati (Noyes) clinician evaluation was used (3). The remaining 73 patients had outcome data measured with the modified Lysholm score (4). Outcome was defined as the change in score to latest follow-up. Z-transformation (z-change) was performed for each score type. The regression model was: z-change = − 0.11 − 0.5*z-preop − 0.43*R4 + 0 .30*OC + 0.20*FC (R2=0.30) The regression analysis showed that the factors which affected outcome were one centre (R4), pre-operative score (z-preop), osteochondral defects (OC), and lesions of the femoral condyle (FC). Factors which were found not to affect outcome included the age of the patient, size of the defect treated, number of defects treated and time to follow-up. Variations in operative technique, including the location of the cartilage harvest, the use of fibrin sealant and the timing of patch placement, were not found to have an effect on clinical outcome.

Conclusions: The method of z-transformation is a useful way of compiling multicentre data where different outcome measures have been used. This has allowed a large dataset to be compiled and factors which influence clinical outcome to be identified.

Introduction: Many designs exist for the femoral component of cemented total hip arthoplasty, but cemented acetabular cups are largely similar. All are essentially hemispheres, made of polyethylene. An important factor determining survival time of cemented implants is cement penetration into the surrounding bone. To ensure sufficient penetration, many surgeons remove the smooth subchondral bone in the acetabulum and drill anchoring holes. This may however weaken the bone. Larger cement pressure during setting will improve penetration. For an acetabular cup, fixation at the rim is most important to prevent loosening, and therefore cement pressure should be high at the rim. A spherical geometry is not ideal to ensure high rim cement pressures. Based on a computer model of cement pressure generation during cup insertion, we designed an improved geometry to ensure higher rim pressures. The aim of this study is to compare the fixation strength of this new design to a conventional design. The effect of the design change will be compared with that of drilling anchoring holes and removing subchondral bone.

Methods: From a larger stock of young bovine acetabula, 14 similarly sized specimens were chosen. Twelve were prepared for a factorial experiment with three factors, based on three cup designs (Ogee either with or without flange, DePuy, Leeds, and the alternative design), preservation or removal of subchondral bone, and presence or absence of anchoring holes. Depth, diameter and position of the anchoring holes were chosen to optimise fixation strength. Two were prepared for replicates of two experiments with the new design, both with sub-chondral bone removed. The order of the experiments was randomised. CMW-3 cement (CMW-DePuy, UK) was hand-mixed for one minute. After four minutes, it was packed in the acetabulum and pressurised for one minute. Then a cup was inserted and manual force applied until setting of the cement. Next, acetabulum and cup were mounted in a materials testing machine and torque applied to the cup until gross failure. Applied force and displacement were sampled into a computer, and used to determine maximum torque.

Results and Discussion: Analysis was done in two steps. First, two-way ANOVA of main effects plus first order interactions was performed. Anchoring holes significantly increased strength (41±8 vs. 114±9 Nm; p=0.004, mean±SEM). No significant effect of reaming or cup design was found. For all experiments, the conventional cups with or without flange behaved almost identical. In step two, these two variations were combined into one “conventional” group, and three-way ANOVA with interactions was performed. Significant interaction between all three factors was found (p=0.02). This indicates that one unique combination (new cup design in acetabula with subchondral bone removed and without anchoring holes) achieved a high average strength. Under these circumstances, the fixation strength of the new design (114±9 Nm) was equal to the overall average achieved with anchoring holes. On average, the new design also had significantly larger fixation strength than a conventional spherical design (95±5 vs. 69±4 Nm; p=0.009). These results justify further studies.

Introduction. Leg length inequality post total hip arthroplasty is a source of patient dissatisfaction. In adult DDH femoral length equality is assumed. Empirically, a longer femur has been observed on the affected side in the presence of unilateral DDH; restoration of the hip centre in this situation may lengthen the affected leg.

Aim. Assessment of femoral length variation in adults with unilateral and bilateral DDH.

Method. Retrospective observation study of 17 adults with unilateral and 7 adults with bilateral DDH. Femoral lengths assessed using CT measurements.

Results. Unilateral DDH. The ipsilateral femur was longer in 11 patients (63%) The degree of femoral lengthening was between 5 and 10 mm. Bilateral DDH. The femur with the greater degree of DDH was longer by a mean of 7.5 19.3 mm .

Conclusion. In the presence of DDH, asymmetry of femoral lengths is common and unpredictable. Careful femoral length assessment ( with CT leg lengths) is advised preoperatively in patients with DDH. This will alert the surgeon and patient to the possible risk of post operative ipsilateral leg lengthening.

Statement of Purpose We describe the donor site morbidity of hyaline cartilage biopsy from the trochlea of the knee when used for ACI in the ankle joint.

Methods We studied 12 patients who received a two stage ACI procedure on the talus, performed by three consultant surgeons. The first stage involved knee arthroscopy and harvest of cartilage for culture and stage two the transplantation of a chondrocyte culture to the ankle joint.

During the first stage knee arthroscopy using a superolateral approach, the cartilage specimens were taken from a minor load bearing area of either the central or superolateral trochlea using a 5mm gouge.

Clinical outcomes were assessed using a patient satisfaction score and the Lysholm knee score, taken both pre- and post- operatively at 3 months and annually thereafter.

Results The mean age of the patient group was 42. The patient satisfaction questionnaires showed 11 patients to be ‘pleased’ or ‘extremely pleased’ with their ACI procedure which was sustained in the patients with up to four years follow up.

The mean Lysholm score preoperatively was 98/100. Postoperatively eight patients had a reduced score (mean reduction 14) at twelve months follow up. In those patients with new knee symptoms at one year, analysis of the Lysholm score components showed the Locking and Limp categories to be the most frequent cause of a reduced score. Two patients had repeat knee arthroscopy at 18 months and 2 years postoperatively for symptoms of catching, anterior knee pain and swelling.

Discussion The Lysholm knee score has components which may be affected by ipsilateral joint problems, which contribute to 20% of the overall score. However those patients with an abnormal Lysholm knee score postoperatively have gained an improved Mazur ankle score since their ACI.

The procedure of cartilage harvest from the trochlea of the knee has an associated donor site morbidity which is present at one year. Ninety two percent of patients were pleased or extremely pleased with their ACI procedure, despite the requirement of surgery on their knee and it would seem that the amount of early knee morbidity these patients experience is outweighed by the improvement in symptoms in the treated joint.

Ideally to optimise cartilage repair less morbid techniques to obtain cartilage need to be identified or alternatively mesenchymal stem cells could be used as an alternative source, which has already had limited success in the knee and might also be applied to other joints.

We present the early results of a bone conserving implant, the Thrust Plate Prosthesis (TPP) used for the revision of failed resurfacings of the hip in nine patients.

Four revisions were for fractured neck of femurs. The original implant in this fracture group was a McMinn resurfacing. The original acetabular component was retained. Five revisions were due to aseptic loosening. Four of the original implants in this group were Beuchal Pappas (BP) resurfacings and one was a Cormet2000 resurfacing.

In the fracture group the average age was 46yrs (34–70). The time from primary to revision surgery was 5.8 months (3–11). The Harris hip scores improved in all patients to their pre fracture level of 90 (83–99).

In the aseptic loosening group the average age was 62yrs (53–67). The time from primary to revision surgery was 121 months for the BP resurfacings and 19 months for the Cormet. The Harris hip scores also improved in this group to an average of 73.8 (50–100).

Hip resurfacing presents an attractive option for the younger patient. It is a bone conserving procedure with the added benefit of increased stability by using a large diameter head. Fracture of the femoral neck is a specific early complication. The usual treatment of this complication has been revision to a more traditional design, loosing the benefits of bone conservation.

The TPP is a bone preserving implant that has metaphyseal fixation of the proximal femur. It has satisfactory long term results (Huggler, 1993). The use of the TPP for revision of failed resurfacings has proved to be straight forward. Our early results are promising in the fracture group, but revision for aseptic loosening did not correlate with a high hip score. It remains to be proven that revision of a bone conserving hip replacement will maintain a high quality function. For the younger patient with a failed resurfacing, revision with a TPP can offer continued bone conservation.

Aim: A retrospective review of the triple pelvic osteotomies performed between 1988 and 2002 identifying the factors that may predict a favourable outcome from surgery.

Method: A case note and x-ray review identifying various parameters that influence outcome.

Results: 30 osteotomies in 26 patients have been studied. 3male and 27 female patients have been identified. All patients were symptomatic prior to surgery complaining of pain and reduced exercise tolerance. Following surgery 21 patients were satisfied with their outcome and 9 patients had poor results.

The average age of patients with a good outcome was 20.9 years. The average age of patients with a poor outcome was 30.9 years.

There was no correlation between the correction of either the Sharp angle or the centre-edge angle and outcome. Sphericity of the head was unrelated to outcome. Obesity was associated with a poorer outcome in older patients.

Conclusion: Triple pelvic osteotomy provides a reliable method of improving symptoms in younger patients with dysplastic hips. An increased rate of failure should be expected in patients over thirty years of age.

Aims: This study aims to identify whether there is seasonal variation in proximal femoral fractures in ageing population. Methods: We carried out a study to find out whether there is a definite variation in the incidence of these fractures. The number of operated proximal femoral fractures across 31 hospitals of Northwest England and Scotland were collected on a monthly basis from 1994 to 1999. This database of 27,000 operated proximal femoral fractures was assessed statistically. Results: Our analysis reveals that the incidence of these fractures during December is about 17% higher than rest of the annual mean with a 2% standard error of the mean (SEM) and in January this increase is about 22% with a SEM of 1%. These trend and pattern were observed for both intra and extra capsular fractures of neck of femur and was consistent over the five years. There was no other significant change in the incidence pattern during other months of the year. Conclusions: This study, one of the largest of its kind ever carried out, proves that there is an increase in the incidence of hip fractures in the months of December and January. There should be appropriate allocation of manpower and rehabilitation facilities during the months of December and January to tackle this seasonal variation.

Introduction: Impaction grafting has become a popular technique to revise implants. The Norwegian Arthroplasty Registry reports its use for a third of all revisions. Yet, the technique is seen as demanding. A particular challenge is to achieve sufficient mechanical stability of the construction. This work tests two hypotheses: (1) Graft compaction is an important determinant of mechanical stability, and (2) Graft compaction depends on compaction effort and graft properties. Methods: Impaction grafting surgery was simulated in laboratory experiments using artificial bones with realistic elastic properties (Sawbones, Malmö, Sweden). Bone stock was restored with compacted morsellised graft, and the joint reconstructed with a cemented implant. The implant was loaded cyclically and its migration relative to bone measured. In a second study, morsellised bone of various particle sizes and bone densities, with or without added ceramic bone substitutes, was compacted into a cylindrical mould by impaction of a plunger by a dropping weight. Plunger displacement was measured continuously. Results: Initial mechanical stability of the prostheses correlated most strongly with degree of graft compaction achieved. Graft compaction to similar strength was achieved with less energy for morsellised bone with larger particles, higher density, or bone mixed with ceramic substitutes. Conclusion: Initial mechanical stability of impaction-grafted joint reconstructions depends largely on degree of graft compaction achieved by the surgeon. Compaction depends partly on the vigour of impaction, and partly on graft quality. Higher bone density, larger particle size and mixing with ceramic particles all help to facilitate graft compaction, giving a stronger compacted mass with less effort.

Aim: The purpose of this study is to investigate the outcomes of bone conserving hip replacements: the Thrust Plate Prosthesis (TPP) and Buechel Pappas (BP) Resurfacing. Method:We have performed total hip replacements in 2 consecutive groups of young patients with osteoarthritis of the hips. In group 1 (TPP group) consists of 103 hips with the thrust plate prosthesis, HA coating and metal on metal bearings (1995~2000). The group 2 (BP group) consists of 25 hips with Buechel Pappas resurfacing with a thin polyethylene liner, ethylene oxide sterilized, and a nitrided titanium bearing surface (1989~1994). The outcomes were evaluated by complication rates, survival, standardized X-rays, a self-assessment satisfaction score, a Harris Hip Score and a Merle dñAubigne score. Results: In group 1, one hip had revision due to infection, and one following traumatic intertrochanteric fracture. No osteolysis and gross migration is seen In group 2, 17 of 25 hips had revision due to osteolysis or femoral neck fracture (mean 4y10m). Conclusion: The Thrust Plate Prosthesis has good outcome at 1 to 6 years follow-up. Buechel pappas resurfacing replacement had poor outcome and almost all cases had osteolysis, which are thought to be due to polyethylene particles.

Patients with osteochondral lesions of the talus have traditionally been difficult to treat. Autologous chondrocyte implantion (ACI) may provide predictable repair through restoring an articular surface. We reviewed our results of Ankle ACI in eight ACI plus two ACI and mosaicplasty combined with an average age of 40 years (32 to 62) performed over four years.

The patients were assessed with a modified Mazur ankle score, patient satisfaction score and Lysholm knee score, pre- and post-operatively. Ankle arthroscopic assessment was performed in patients at 12 months post surgery. The average time to follow up was 24 months (range two to 52). The osteochondral lesions were post traumatic in seven cases, with seven lesions situated medially and three anterolaterally. The average size of the talar defects at surgery was 2.25cm (range 1 to 4 cm.)

Patient satisfaction scores in eight patients were either “extremely pleased” or “pleased” with the operation which was sustained in the patients at up to four years follow up. The Mazur scores increased by 23 points at mean 24 months follow up. Six patients with over 12 months follow up maintained a markedly improved ankle score. Patients were noted to rehabilitate twice as quickly as patients receiving ACI to the knee.

The Lysholm knee scores returned to the preoperative level in four patients, with the remaining six patients showing a reduced score (mean 12 points), suggesting there may be some donor site morbidity. Five had ankle arthroscopy at one year and were shown to have filled defects and stable cartilage. A biopsy taken from the graft site showed hyaline like cartilage and fibrocartilage to be present These early results suggest that ankle ACI is an appropriate treatment for large symptomatic osteochondral lesions in the talus.

We studied the effect of 'dynamisation' on tibial fractures in six patients treated by the Dynamic Axial Fixator. In the early stages, peak cyclic movement at two to four weeks averaged 0.75 mm (0.19 to 1.02) on the medial side of the bone and 0.86 mm (0.21 to 1.25) on the lateral side. The amount of movement correlated with the applied load and the fracture stiffness. After unlocking the fixator column at six weeks, progressive closure of the gap averaged 1.3 mm (0.1 to 3.5). Cyclic movement is produced by early weight-bearing with the fixator column locked. Progressive closure occurs after unlocking the column, and is often associated with a reduction in cyclic movements. The effects of dynamisation on movement at the fracture site should be defined separately, in terms of cyclic movement and of progressive closure.

We measured fracture stiffness in 212 patients with tibial fractures treated by external fixation. In the first 117 patients (group 1) the decision to remove the fixator and allow independent weight-bearing was made on clinical grounds. In the other 95 patients (group 2) the frames were removed when the fracture stiffness had reached 15 Nm/degree. In group 1 there were eight refractures and in group 2 there was none (p = 0.02, Fisher's exact test). The time to independent weight-bearing was longer in group 1 (median 24 weeks) than in group 2 (21.7 weeks, p = 0.02). The greater precision of our objective measurement was associated with a reduction in refracture rate and in the time taken to achieve independent weight-bearing. We consider that a stiffness of 15 Nm/degree in the sagittal plane provides a useful definition of union of tibial fractures.

Cephamandole levels in serum and drain fluid were measured in 32 knee replacement operations to determine the benefit of an intravenous dose of antibiotic at the time of tourniquet deflation. Concentrations of cephamandole in drain fluid were directly proportional to the serum concentration at the time of tourniquet release. A 'tourniquet-release' dose of antibiotic increased drain fluid concentration threefold.

Diaphyseal fractures of the tibia in 80 patients were treated by external skeletal fixation using a unilateral frame, either in a fixed mode or in a mode which allowed the application of a small amount of predominantly axial micromovement. Patients were allocated to each regime by random selection. Fracture healing was assessed clinically, radiologically and by measurement of the mechanical stiffness of the fracture. Both clinical and mechanical healing were enhanced in the group subjected to micromovement, compared to those treated with frames in a fixed mode possessing an overall stiffness similar to that of others in common clinical use. The differences in healing time were statistically significant and independently related to the treatment method. There was no difference in complication rates between treatment groups.

It is difficult to establish the diagnosis of an injured shoulder if only one radiographic projection is used. We have compared two lateral projections, the Neer trans-scapular and the apical oblique in 80 patients; the radiographs were presented randomly to 10 casualty officers and nine radiologists. The apical oblique view was found to permit more accurate diagnosis of fractures and of dislocation by both groups.