Aims

Retrospective review of a consecutive series of 1,168 total ankle replacements (TAR) performed at Wrightington, to analyse modes of failure and clinical outcomes following TAR failure.

Introduction

This is a multi-centre, prospective, observational study of 503 INFINITY fixed bearing total ankle arthroplasties. We report the minimum two-year results of this prosthesis which was introduced to the UK Market in 2014 and is now the most used ankle arthroplasty in the National Joint Registry of England and Wales.

To determine the risk of total knee replacement (TKR) for primary osteoarthritis (OA) associated with overweight/obesity in the Australian population.

This population-based study analyzed 191,723 cases of TKR collected by the Australian Orthopaedic Association National Joint Registry and population data from the Australian Bureau of Statistics. The time-trend change in incidence of TKR relating to BMI was assessed between 2015-2018. The influence of obesity on the incidence of TKR in different age and gender groups was determined. The population attributable fraction (PAF) was then calculated to estimate the effect of obesity reduction on TKR incidence.

The greatest increase in incidence of TKR was seen in patients from obese class III. The incidence rate ratio for having a TKR for obesity class III was 28.683 at those aged 18-54 years but was 2.029 at those aged >75 years. Females in obesity class III were 1.7 times more likely to undergo TKR compared to similarly classified males. The PAFs of TKR associated with overweight or obesity was 35%, estimating 12,156 cases of TKR attributable to obesity in 2018. The proportion of TKRs could be reduced by 20% if overweight and obese population move down one category.

Obesity has resulted in a significant increase in the incidence of TKR in the youngest population in Australia. The impact of obesity is greatest in the young and the female population. Effective strategies to reduce the national obese population could potentially reduce 35% of the TKR, with over 10,000 cases being avoided.

Proximal femoral focal deficiency is a congenital disorder of malformation of the proximal femur and/or the acetabulum. Patients present with limb length discrepancy and clinical features along a spectrum of severity. As these patients progress through to skeletal maturity and on to adulthood, altered biomechanical demands lead to progression of arthropathy in any joint within the lower limb. Abnormal anatomy presents a challenge to surgeons and conventional approaches and implants may not necessarily be applicable.

We present a case of a 62-year-old lady with unilateral proximal femoral focal deficiency (suspected Aitken Class A) who ambulated with an equinus prosthesis for her entire life. She presented with ipsilateral knee pain and instability due to knee arthritis but could not tolerate a total knee arthroplasty due to poor quadriceps control.

A custom osteointegration prosthesis was inserted with a view to converting to the proximal segment to a total hip replacement if required. The patient went on to develop ipsilateral symptomatic hip arthritis but altered acetabular anatomy required a custom tri-flange component (Ossis, Christchurch, New Zealand) and a custom proximal femoral component to link with the existing osseointegration component (Osseointegration Group of Australia, Sydney, Australia) were designed and implanted.

The 18 month follow up of the custom hip components showed that the patient had Oxford hip scores that were markedly improved from pre-operatively. Knee joint heights were successfully restored to equal when the patient's prosthesis was attached. The patient describes feeling like “a normal person”, walks unaided for short distances and can ambulate longer distances with crutches.

Advances in design and manufacture of implants have empowered surgeons to offer life improving treatments to patients with challenging anatomy. Using a custom acetabular tri-flange and osseointegration components is one possible solution to address symptomatic ipsilateral hip and knee arthropathy in the context of PFFD in adulthood.

Rates of prosthetic joint infection in megaprostheses are high. The application of silver ion coating to implants serves as a deterrent to infection and biofilm formation.

A retrospective review was performed of all silver-coated MUTARS endoprosthetic reconstructions (SC-EPR) by a single Orthopaedic Oncology Surgeon. We examined the rate of component revision due to infection and the rate of infection successfully treated with antibiotic therapy. We reviewed overall revision rates, sub-categorised into the Henderson groupings for endoprosthesis modes of failure (Type 1 soft tissue failure, Type 2 aseptic loosening, Type 3 Structural failure, Type 4 Infection, Type 5 tumour progression).

283 silver-coated MUTARS endoprosthetic reconstructions were performed for 229 patients from October 2012 to July 2022. The average age at time of surgery was 58.9 years and 53% of our cohort were males. 154 (71.3%) patients underwent SC-EPR for oncological reconstruction and 32 (14.8%) for reconstruction for bone loss following prosthetic joint infection(s). Proximal femur SC-EPR (82) and distal femur (90) were the most common procedures. This cohort had an overall revision rate of 21.2% (60/283 cases). Component revisions were most commonly due to Type 4 infection (19 cases), Type 2 aseptic loosening/culture negative disease (15 cases), and Type 1 dislocation/soft tissue (12 cases).

Component revision rate for infection was 6.7% (19 cases). 15 underwent exchange of implants and 4 underwent transfemoral amputation due to recalcitrant infection and failure of soft tissue coverage. This equates to a limb salvage rate of 98.3%. The most common causative organisms remain staphylococcus species (47%) and polymicrobial infections (40%).

We expand on the existing literature advocating for the use of silver-coated endoprosthetic reconstructions. We provide insights from the vast experience of a single surgeon when addressing patients with oncological and bone loss-related complex reconstruction problems.

The Australia and New Zealand Sarcoma Association established the Sarcoma Guidelines Working Party to develop national guidelines for the management of Sarcoma. We asked whether surgery at a specialised centre improves outcomes. A systematic review was performed of all available evidence pertaining to paediatric or adult patients treated for bone or soft tissue sarcoma at a specialised centre compared with non-specialised centres. Outcomes assessed included local control, limb salvage rate, 30-day and 90-day surgical mortality, and overall survival.

Definitive surgical management at a specialised sarcoma centre improves local control as defined by margin negative surgery, local or locoregional recurrence, and local recurrence free survival. Limb conservation rates are higher at specialised centres, due in part to the depth of surgical experience and immediate availability of multidisciplinary and multimodal therapy. A statistically significant correlation did not exist for 30-day and 90-day mortality between specialised centres and non-specialised centres. The literature is consistent with improved survival when definitive surgical treatment is performed at a specialised sarcoma centre.

Evidence-based recommendation: Patients with suspected sarcoma to be referred to a specialised sarcoma centre for surgical management to reduce the risk of local recurrence, surgical complication, and to improve limb conservation and survival.

Practice point: Patients with suspected sarcoma should be referred to a specialised sarcoma centre early for management including planned biopsy.

Complex acetabular reconstruction for oncology and bone loss are challenging for surgeons due to their often hostile biological and mechanical environments. Titrating concentrations of silver ions on implants and alternative modes of delivery allow surgeons to exploit anti-infective properties without compromising bone on growth and thus providing a long-term stable fixation. We present a case series of 12 custom acetabular tri-flange and custom hemipelvis reconstructions (Ossis, Christchurch, New Zealand), with an ultrathin plasma coating of silver particles embedded between layers of siloxane (BioGate HyProtect™, Nuremberg, Germany).

At the time of reporting no implant has been revised and no patient has required a hospital admission or debridement for a deep surgical site infection. Routine follow up x-rays were reviewed and found 2 cases with loosening, both at their respective anterior fixation. Radiographs of both cases show remodelling at the ilium indicative of stable fixation posteriorly. Both patients remain asymptomatic. 3 patients were readmitted for dislocations, 1 of whom had 5 dislocations within 3 weeks post-operatively and was immobilised in an abduction brace to address a lack of muscle tone and has not had a revision of their components.

Utilising navigation with meticulous implant design and construction; augmented with an ultrathin plasma coating of silver particles embedded between layers of siloxane with controlled and long-term generation of silver ion diffusion has led to outstanding outcomes in this series of 12 custom acetabular and hemipelvis reconstructions. No patients were revised for infection and no patients show signs of failure of bone on growth and incorporation. Hip instability remains a problem in these challenging mechanical environments and we continue to reassess our approach to this multifaceted problem.

Aims

Avulsion of the proximal hamstring tendon origin can result in significant functional impairment, with surgical re-attachment of the tendons becoming an increasingly recognized treatment. The aim of this study was to assess the outcomes of surgical management of proximal hamstring tendon avulsions, and to compare the results between acute and chronic repairs, as well as between partial and complete injuries.

Aims

This study aimed to identify patients receiving total hip arthroplasty (THA) for trauma during the peak of the COVID-19 pandemic in the UK and quantify the risks of contracting SARS-CoV-2 virus, the proportion of patients requiring treatment in an intensive care unit (ICU), and rate of complications including mortality.

Aims

This study aimed to determine if macrophages can attach and directly affect the oxide layers of 316L stainless steel, titanium alloy (Ti6Al4V), and cobalt-chromium-molybdenum alloy (CoCrMo) by releasing components of these alloys.

Introduction

Total hip arthroplasty (THA) is a physically demanding procedure where the surgeon is subject to fatigue with increased energy expenditure comparable to exercise[1]. Robotic technologies have been introduced into operating rooms to assist surgeons with ergonomically challenging tasks and to reduce overall physical stress and fatigue[2]. Greater exposure to robotic assisted training may create efficiencies that may reduce energy expenditure[3]. The purpose of this study was to assess surgeon energy expenditure during THA and perceived mental and physical demand.

Hip fracture care is complex multi-disciplinary. We hypothesise that quality of care is affected by variance in resources between ‘in-hours’ (Monday-Friday, 0800–1700) and ‘out-of-hours’ services.

This prospective multicentre national cohort study assessed quality of care by evaluating adherence to the evidence-based Scottish Standards of Care for Hip Fracture Patients. Data was collected by the Scottish Hip Fracture Audit for 15174 patients admitted to any of 22 Scottish hospitals from January 2014-April 2018.

11197/15174 (73.8%) patients were admitted out-of-hours. They were significantly less likely to meet the following Standards: ED Big-6-Bundle (OR 0.85, p= 0.002); Time in ED <4 hours (OR 0.76, p< 0.001); avoidance of repeated fasting (OR 0.80, p< 0.001), and avoidance of prolonged fluid fasting (OR 0.83, p< 0.001). Out-of-hours admissions were more likely to receive: geriatric assessment <3 days (OR 1.16, p< 0.001); OT input <3 days (OR 1.10, p= 0.013), and PT input <2 days (OR 1.44, p< 0.001). There were no significant differences for: Time to Theatre <36 hours; Inpatient Care Bundle <24 hours, and Post-op Day 1 Mobilisation.

Quality of hip fracture care is affected by time of admission. ED care is poorer out-of-hours, which may reflect limited resources, and out-of-hours admissions are more likely to be excessive fasted excessively. Weekday in-hours admissions are less likely to receive geriatric and allied health professional input in the days following admission, which may reflect the reduced weekend services. Examination of out-of-hours service organisation is required for the pursuit of consistent, equitable care for hip fracture patients.

Introduction

Traditional treatment for end-stage ankle arthritis has been ankle arthrodesis, however ankle arthroplasty is becoming an accepted alternative.

The Zenith Ankle (Corin, UK) is 3rd generation implant with a mobile bearing design. In the NJR 2016 report, the Zenith was the commonest ankle prosthesis implanted in the UK. However, compared to other ankle implants, there's little published data on its performance and survival. The aim of this study was to analyse outcome in a consecutive series from a non-designer centre.

In a society whereby the incidence of obesity is increasing and medico-legal implications of treatment failure are more frequently ending with the consulting doctor, clarity is required as to any restrictions placed on common orthopaedic implants by manufacturing companies. The aim of this study was to identify any restrictions placed on the commonly used femoral stem implants in total hip replacement (THR) surgery, by the manufacturers, based on patient weight. The United Kingdom (UK) National Joint Registry (NJR) was used to identify the five most commonly used cemented and uncemented femoral stem implants during 2012. The manufacturing companies responsible for these implants were asked to provide details of any weight restrictions placed on these implants. The Corail size 6 stem is the only implant to have a weight restriction (60Kg). All other stems, both cemented and uncemented, were free of any restrictions. Fatigue fracture of the femoral stem has been well documented in the literature, particularly involving the high nitrogen stainless steel cemented femoral stems and to a lesser extent the cemented cobalt chrome and uncemented femoral stems. In all cases excessive patient weight leading to increased cantilever bending of the femoral stem was thought to be a major factor contributing to the failure mechanism. From the current literature there is clearly an association between excessive patient weight and fatigue failure of the femoral stem. We suggest avoiding, where possible, the insertion of small stems (particularly cemented stems) and large offset stems (particularly those with a modular neck) in overweight patients.

Introduction:

The ASR™ Articular Surface Replacement and ASR™ XL Metal-on-Metal systems were recalled due to high revision rates at five years. A worldwide clinical follow-up of patients was initiated. This paper summarizes current findings in South Africa (SA) in comparison with those outside SA (OSA).

Introduction:

The aim of this study was to identify the rate of complications of total ankle replacement in a single Centre to help with informed patient consent.

We aimed to determine whether cemented hemiarthroplasty is associated with a higher post-operative mortality and rate of re-operation when compared with uncemented hemiarthroplasty. Data on 19 669 patients, who were treated with a hemiarthroplasty following a fracture of the hip in a nine-year period from 2002 to 2011, were extracted from NHS Scotland’s acute admission database (Scottish Morbidity Record, SMR01). We investigated the rate of mortality at day 0, 1, 7, 30, 120 and one-year post-operatively using 12 case-mix variables to determine the independent effect of the method of fixation. At day 0, those with a cemented hemiarthroplasty had a higher rate of mortality (p < 0.001) compared with those with an uncemented hemiarthroplasty, equivalent to one extra death per 424 procedures. By day one this had become one extra death per 338 procedures. Increasing age and the five-year co-morbidity score were noted as independent risk factors. By day seven, the cumulative rate of mortality was less for cemented hemiarthroplasty though this did not reach significance until day 120. The rate of re-operation was significantly higher for uncemented hemiarthroplasty. Despite adjusting for 12 confounding variables, these only accounted for 15% of the observed variability.

The debate about the choice of the method of fixation for a hemiarthroplasty with respect to the rate of mortality or the risk of re-operation may be largely superfluous. Our results suggest that uncemented hemiarthroplasties may have a role to play in elderly patients with significant co-morbid disease.

Cite this article: Bone Joint J 2014;96-B:1185–91.

The Bone & Joint Journal provides the latest evidence to guide the clinical practice of orthopaedic surgeons. The benefits of one intervention compared with another are presented using outcome measures; some may be specific to a limb or joint and some are more general health-related quality of life measures. Readers will be familiar with many of these outcome measures and will be able to judge the relative benefits of different interventions when measured using the same outcome tool; for example, different treatments for pain in the knee measured using a particular knee score. But, how should readers compare outcomes between different clinical areas using different outcome measures? This article explores the use of standardised effect sizes.

Cite this article: Bone Joint J 2014;96-B:853–4.

Summary Statement

Transportation media and injection protocol have implications for the viability of MSCs used for intra-lesional treatment of tendon injuries. Every effort should be made to implant cells within 24h of laboratory re-suspension, using a needle bore larger than 21G.

Summary

Wear particles from joint replacements may result in loosening and periprosthetic osteolysis. Interference with systemic macrophage trafficking to the implant, modulation of macrophage phenotype from M1 to M2, and inhibition of NFκB may mitigate these adverse effects.

Summary Statement

This work raises the potential of utilizing stem cells to catalyze cartilage regeneration by a minimal number of neonatal chondrocytes via controlling cell distribution in 3D matrices, and may solve the challenge of scarce donor availability associated with cell-based therapy.

The surgical treatment options for patients who have sustained an intra-capsular hip fracture can vary depending on a number of patient and fracture related factors. Currently most national guidelines support the use of cemented prostheses for patient undergoing hemi-arthroplasty surgery. Uncemented prostheses are commonly used for a variety of indications including those patients who have significant medical co-morbidities.

To determine whether cemented hemi-arthroplasty is associated with a higher post operative mortality when compared to uncemented procedures. Data was extracted from the Scottish SMR01 database from 01/04/1997 from all patients who were admitted to hospital after sustaining a hip fracture. We investigated mortality at day 1, 2, 4, 7, 30, 120 and 1 year from surgery vs. that on day 0. In order to control for the effects of confounding variables between patients cohorts, 12 case-mix variable were used to construct a multivariable logistic regression analysis model to determine the independent effect of prosthesis fixation method.

There were 64,979 patients were included in the study. Mortality for osteosynthesis of extra-capsular fractures was consistently lower when compared to that for surgical procedures for intra-capsular fractures. At day 0, uncemented hemi-arthroplasty operations had a lower associated mortality (p<0.001) when compared to cemented implant designs. Unadjusted figures showed an increased mortality equal to 1 extra death per 424 procedures. By day 1 this had become 1 extra death per 338 procedures. By day 7 cumulative mortality was less for cemented than for uncemented procedures though this did not reach significance until day 120.

When compared to uncemented fixation techniques, cemented hemiarthroplasty is associated with a higher mortality in the immediate postoperative period. However, by day 120 and beyond the trend is reversed.

Introduction

Decompression is the gold standard surgical technique in patients with symptomatic spinal stenosis not responding to conservative management. We present an audit of outcomes in a population of patients undergoing this procedure over a four year period.

The importance for observing the intention-to-treat approach in clinical studies is explained.

Cite this article: Bone Joint J 2013;95-B:1443–4.

It is estimated that 15 % of the population is allergic to metal, most commonly to Nickel, which is a common component of the alloys in most knee and hip arthroplasties. It would therefore be expected that allergy to metal is a frequent form of implant failure – but very little is reported in the literature. With the recent concerns about metal-on-metal bearings and metal ion issues, there has been renewed interest in metal allergy – with the Australian Joint Registry 2010 reporting it as a causative factor in 7 % of Hip Resurfacing revisions.

With over 200 BHR and 571 ASR Hip Resurfacing arthroplasties in my series from 2001, I have identified only 1 patient with implant failure due to metal allergy.

In 2010 two Total Knee Arthroplasty patients presented with pain and strongly positive Melisa allergy tests – these patients were revised to Titanium coated implants resulting in a complete relief of symptoms.

This paper will analyse the problem of metal sensitivity, the investigation and management of the allergic patient who has, or requires, joint arthroplasty

The surgical treatment options for patients who have sustained an intra-capsular hip fracture can vary depending on a number of patient and fracture related factors. Currently most national guidelines support the use of cemented prostheses for patient undergoing hemiarthroplasty surgery. Uncemented prostheses are commonly used for a variety of indications including those patients who have significant medical co-morbidities.

To determine whether cemented hemiarthroplasty is associated with a higher post operative mortality when compared to uncemented procedures. Data were extracted from the Scottish SMR01 database from 01/04/1997 from all patients who were admitted to hospital after sustaining a hip fracture. We investigated mortality at day 1,2,4,7,30, 120 and 1 year from surgery vs. that on day 0. In order to control for the effects of confounding variables between patients cohorts, 12 case-mix variable were used to construct a multivariable logistic regression analysis model to determine the independent effect of prosthesis design.

There were 52283 patients included in the study. Mortality for osteosynthesis of extra-capsular fractures was consistently lower when compared to that for surgical procedures for intra-capsular fractures. At day 0, uncemented hemiarthroplasty had a lower associated mortality (p<0.001) when compared to cemented implant designs. However, this increased mortality was equal to 1 extra death per 2000 procedures. From day 1 onward mortality for cemented procedures was equal to or lower than that of uncemented. By day 4, cumulative mortality was less for cemented than for uncemented procedures. Complication and re-operation rate was significantly higher in the uncemented cohort.

The use of uncemented hemiarthroplasty for the treatment of intra-capsular hip fractures cannot be justified in terms of early/late post-operative mortality.

Aim

Congenital Talipes Equinovarus (CTEV) has been excluded from the standards set by the NHS fetal anomaly screening programme (NHS FASP) for the 18⁺⁰–20⁺⁶ week fetal ultrasound scan (USS). Whilst adhering to NHS FASP guidelines, the antenatal ultrasound department at our centre performs “incidental screening” for CTEV; parents are informed if CTEV is noted incidentally during the scan and referral made to the fetal medicine department. Our aim was to investigate the effectiveness of incidental antenatal screening for structural CTEV.

Background and Purpose

Serum lactate has been shown to be an indicator of adverse clinical outcomes in patients admitted secondary to general trauma or sepsis. We retrospectively investigated whether admission serum venous lactate can predict in-hospital mortality in patients with hip fractures.

The risk of venous thrombo-embolism (VTE) is high in orthopedics. Oral direct factor Xa inhibitors have been introduced to help reduce the incidence of VTE. To reduce post-operative bleeding antifibrinolytics are used. We aimed to ascertain the effect of two drugs on post operative bleeding and transfusion requirements.

We prospectively recorded patient demographics, operative details, complications, transfusion incidence and VTE incidence in TKR patients. We also sent out questionnaires to patients asking about wound bleeding and VTE. All patients were given 10mg Rivaroxaban 8 hours post operatively and then OD for 14 or 35 days. Patients given tranexamic acid were given 500mg IV, 5 minutes prior to wound closure at the discretion of the surgeon. VTE was Deep Vein Thrombus or Pulmonary Embolism confirmed by Doppler or CTPA. Minor bleed was categorized as dressing soakage or reported wound leakage, major bleed as hematoma requiring revision within 30 days.

509 patients underwent TKR: 200 (39%) received Rivaroxaban only (Group 1), 296 (58%) also received tranexamic acid (Group 2). 13 (3%) patients had no data available. Five patients had a VTE: 4 (2%) in Group 1, 1 (0.3%) in Group 2 [P<0.05]. 39 patients had a minor bleed: 17 (8.5%) in Group 1, 22 (7.4%) in Group 2 [P=0.5]. 2 patients had major bleeds: 1(0.5%) in Group 1 and 1(0.33%) in Group 2 [P=0.69]. There were 30 blood transfusions: 21 (10.5%) in Group 1, 9 (3%) in Group 2 [P<0.0001].

We have demonstrated a reduced requirement for blood transfusions in the tranexamic acid group. However our results, whilst they show a trend towards decreased minor and major bleeding rates, are not significant and require larger studies looking at wound bleeding and leakage.

The risk of venous thrombo-embolism (VTE) is high in orthopaedics. Oral direct factor Xa inhibitors have been introduced to help reduce the incidence of VTE. To reduce post-operative bleeding antifibrinolytics are used. We aimed to ascertain the effect of two drugs on post-operative bleeding and transfusion requirements.

We prospectively recorded patient demographics, operative details, complications, transfusion incidence and VTE incidence in TKR patients. We also sent out a questionnaire to patients asking about wound bleeding and VTE. All patients were given 10mg Rivaroxaban 8 hours post operatively and then once a day for 14 days. Patients given tranexamic acid were given 500mg IV, 5 minutes prior to wound closure at the discretion of the surgeon. VTE was confirmed by Doppler or CTPA as Deep Vein Thrombus or Pulmonary Embolism. Minor bleed was categorised as dressing soakage or reported wound leakage, major bleed as haematoma requiring revision within 30 days.

509 patients underwent TKR: 200(39%) only received Rivaroxaban (Group 1), 296(58%) also received tranexamic acid (Group 2). 13(3%) of patients had no data available. 5 patients had a VTE: 4 (2%) Group 1, 1 (0.3%) Group 2 (P<0.05). 39 patients had a minor bleed: 17 (8.5%) Group 1, 22 (7.4%) Group 2 (P=0.5). 2 patients had major bleeds: 1 (0.5%) Group 1, 1 (0.33%) Group 2 (P=0.69). Blood transfusions 21: (10.5%)Group 1, 9 (3%) Group 2 (P<0.0001).

We have demonstrated a reduced requirement for blood transfusions in the tranexamic acid group. However our results whilst they show a trend towards decrease bleeding rates in both the minor and major bleeds are not significant, requiring larger studies looking at wound bleeding and leakage.

Delay to theatre after hip fracture is common in order to medically optimise the patient prior to surgery. The association between delay to surgery and mortality after hip fracture remains a contentious issue.

We aimed to investigate how medical postponement, time to surgery and correction of medical abnormalities prior to surgery affect peri-operative mortality after hip fracture.

From February to December 2007 prospective data was collected from all acute trauma units in Scotland relating to hip fracture patients' fitness for theatre, reasons for postponement of surgery and subsequent plans of action. The data-set recorded whether medical abnormalities were identified following criteria reported by McLaughlin et al. Survival at 30-days post-operation was used as primary outcome measure. Multivariable logistic regression models were used to control for differences in case-mix between patients.

Data were available for 4284 patients. Patients postponed for medical reasons were less likely to survive to 30 days compared to patients who were not postponed (87% (122/947) versus 93% (3098/3337)). Survival also decreased as time to theatre increased - 92% of patients operated on during the same/next day vs. 89% of those operated on admission day four. However, after controlling for differences in case-mix variables and co-morbidities, neither variable significantly affected survival. We then analysed whether delaying surgery to resolve medical problems improved survival. Adjusted survival was not significantly different between those patients who had their medical problem resolved prior to surgery compared to those patients who were not postponed. Individuals who were postponed but did not have their clinical abnormality resolved prior to surgery had significantly lower adjusted 30 day survival.

The possible benefits of postponement need to be weighed against prolonged discomfort and the possibility of developing other complications. Postponing patients who cannot be medically improved should be avoided.

Richard Carey Smith is an orthopaedic oncology surgeon with fellowship training in the UK, USA, Australia and Canada, and has worked in Zambia, Zimbabwe and Papa New Guinea. David Wood is head of the University Department of Orthopaedics in Perth, Western Australia. He did his masters in Africa, and first experienced Papa New Guinea on his medical elective, starting a lifelong commitment to medical aid work there.

Introduction

A metal ion study was undertaken in patients who had received an articular surface replacement. The design of these components is optimised in line with lubrication theory and produces low levels of wear in hip joint simulators.

We aim to assess the outcome of ankle arthrodesis performed for painful osteoarthritis in the presence of a coronal plane deformity of 20 degrees or more.

To our knowledge this is the first reported series of such a cohort of patients. We have a consecutive and complete series of 24 patients with 26 ankle arthrodeses which were all performed for painful osteoarthritis in the presence of large coronal plane deformity. These patients have a minimum of twelve months clinical follow-up. The results showed a low non-union rate of 8% (2 ankles). These have subsequently been re-fused satisfactorily, and are excluded from further analysis. The results of the remaining 24 ankles, which united primarily, show that patients were very pleased with the outcome of their surgery. AOFAS scores were used to measure pain and function, both pre-operatively and post-operatively. These scores showed large improvements for both pain and function, and had a high statistical significance (p<0.0001). All patients improved in their walking distance and many patients reduced their need for walking aids. Stair climbing ability was also improved in some patients. It is recognised that an ankle arthrodesis usually relieves pain but does not result in a normal gait and full function.

We feel that the high level of patient satisfaction in this series was due to the combination of deformity correction, restoring a functional foot position, and achieving a painless ankle. Arthroplasty of the ankle is a good procedure for relief of pain and restoration of function. However, in the presence of a large coronal plane deformity, ankle arthroplasty is known to fare badly with early failure. Therefore for patients with painful osteoarthritis and a coronal plane deformity of 20 degrees or more, we recommend ankle arthrodesis as the procedure of choice.

Surgery for degenerative lumbar spondylolisthesis may entail both decompression and fusion. The knee-chest position facilitates the decompression, but fixation in this position risks fusion in kyphosis. This can be avoided by intra-operative re-positioning to the prone position. The aim of this study was to quantify the restoration of lordosis achieved by intra-operative repositioning and to assess the clinical and radiological outcome.

A total of forty consecutive patients with degenerative lumbar spondylolisthesis and stenosis were treated by posterior decompression and interbody fusion with pedicle screw fixation. The screw insertion, decompression and interbody grafting were performed with the patient in the knee-chest position. The patient was then re-positioned to the fully prone position for fusion. Sagittal plane angles were measured pre-, intra- and post-operatively. Clinical assessment was performed using SF-36 scores and visual analogue scores for back and leg pain.

The sagittal plane angle increased from median 16.0 degrees pre-operatively to 23.1 degrees post-operatively (p<0.01) and this was maintained at the last follow-up (mean 21 months). The SF-36 scores improved for 7 out of 8 domains and the physical score improved from 29% to 40% (p<0.05). The mean pain scores improved significantly from 7.5 to 3.8 for back pain and from 7.6 to 3.7 for leg pain (p<0.001).

Lumbar spondylolisthesis was found to be associated with a reduction of normal lumbar lordosis and the knee-chest position exacerbates this loss of lordosis. Intra-operative repositioning restored lordosis to greater than the pre-operative angle and was associated with a good clinical outcome.

Introduction: Chondral injuries of the knee are commonly seen at arthroscopy, yet there is no consensus on the most appropriate treatment method. However, untreated cartilage injury predisposes to osteoarthritis contributing to pain and disability. For cell-based cartilage repair strategies, an ex vivo expansion phase is required to obtain sufficient cells for therapeutic intervention. Although recent reports demonstrated the central role of oxygen in the function and differentiation of chondrocytes, little is known of the effect of physiological low oxygen concentrations during the expansion of the cells and whether this alters their chondrogenic capacity.

Methods: Articular mouse chondrocytes were prepared from the distal femoral condyles of adult mice and chondrocytes were liberated by collagenase type II treatment. Cells were cultured in RPMI 1640 media in monolayer under normoxic or hypoxic conditions (5% O2). Chondrogenic potential was subsequently assessed by plating the cells under micromass conditions and glycosaminoglycan deposition was determined by alcian blue staining. Having determined that oxygen tension infiuences murine chondrocyte expansion and differentiation, similar studies were conducted using adult human chondrocytes taken from knee arthroplasty off-cuts, and Aggrecan (ACAN) gene expression was analyzed using real-time quantitative PCR.

Results: Cellular morphology of cells from mouse articular cartilage was improved in hypoxic culture, with a markedly more fibroblastic appearance seen after greater than 2 passages in normoxic conditions. Micromass cultures maintained in hypoxic conditions demonstrated stronger staining with alcian blue, indicating stronger expression of cartilage-associated glycosaminoglycans. Expansions of human chondrocytes under hypoxic conditions led to an ~ 2-fold increase in the expression of ACAN in comparison to cells in normoxic conditions. Differentiation of passage 2 chondrocytes under hypoxic conditions also improved the expression of ACAN when compared to culturing under normoxia. Ten day hypoxic cultures exhibited an ~ 5-fold increase in ACAN expression in comparison to normoxic cultures. Interestingly, ACAN expression normoxic-cultured cells could be increased by > 4-fold by transfer to hypoxic conditions.

Conclusions: In vivo, the chondrocytes are adapted to an avascular hypoxic environment. Accordingly, applying 5% O2 in the expansion phase in the course of cell-based cartilage repair strategies may more closely mimic the normal chondrocyte microenvironment and may result in a repair tissue with higher quality by increasing the content of glycosaminoglycans.

Current evidence on the indications for and efficacy of non-rigid lumbar stabilisation remains unclear. The aim of this study was to review the outcome of the DYNESYS system (Zimmer, Inc.) in a consecutive series of 34 patients undergoing this procedure between 2001 and 2006.

Prospectively collected outcome measure data obtained pre-operatively and at 1 year post-operatively was analysed using the Wilcoxon Signed Rank Test. Kaplan Meier survival analysis was performed using revision surgery as the end point. Cox Regression was utilised to identify variables that were related to implant survival.

Pain rating on the visual analogue scale improved from a mean of 7 pre-op to 4 at 1 year (p=0.009), Roland Morris Disability Questionnaire scores from 13 to 9 (p=0.02), Modified Somatic Perception Questionnaire from 13 to 9 (p=0.03). When reporting subjective outcome, 54% of patients reported “better” or “much better” outcomes at last followup (12–69 months post op). Eight patients (25%) required removal of the implant and conversion to fusion, one of whom had deep infection. Kaplan Meier survival analysis revealed a survival of 78% at 5 years (95% CI, 60 – 96%). Previous spinal surgery was significantly related to the time of survival of the implant (p=0.008).

Our study has demonstrated a high revision rate for this implant and 54% patient satisfaction. We recommend that patients be counseled regarding these risks and further use of this implant should be subject to the outcome of larger studies and randomised controlled trials.

We aim to assess the clinical and radiological outcome following cartilage repair in the knee using the TruFit plug (Smith & Nephew). Eleven active sporting patients underwent cartilage repair using TruFit plugs between February 2006 and August 2007. Postoperatively patients were touch weight bearing for 2 weeks and partial until 4 weeks.

Data was collected prospectively, patients underwent clinical review and completed Lysholm, IKDC subjective, Tegner, KOOS and SF-36 scores pre-operatively and at 6 monthly intervals. One patient has been excluded from the analysis as she emigrated and was lost to follow up. The remaining 10 patients (mean age 35 years (21–49)) had defects on the medial femoral condyle (n=6), lateral femoral condyle (n=3), and lateral trochlea (n=1). Patients received one (n=5), two (n=3) or three (n=2) plugs and four were primary procedures, and six revision procedures (1 failed OATS, 5 failed microfracture). Eight implantations were performed arthroscopically and, and two were mini-open. All patients were reviewed at 12 months, five were reviewed at 18 months and four have also been reviewed at 24 months.

Statistically significant improvements from mean pre-operative scores are seen at 12 months; Lysholm (48.3 to 71), IKDC Subjective (37.7 to 65.1), Tegner (2.4 to 4.6), SF36 physical (39.5 to 50.3) and all components of KOOS. These improvements are maintained at the latest follow up. MRI evaluation including T2 mapping demonstrates reformation of the subchondral lamina, resorption of the graft and a similar signal from neo-cartilage as that of adjacent native cartilage.

TruFit plugs offer an exciting novel solution for cartilage repair in the knee with advantages of low morbidity and rapid recovery without the need for prolonged non-weight bearing. The implant may be suitable for small lesions only and further prospective study is required to establish long-term outcome.

Peri-prosthetic fracture after joint replacement in the lower limb is associated with significant morbidity. The primary aim of this study was to investigate the incidence of peri-prosthetic fracture after total hip replacement (THR) and total knee replacement (TKR) over a ten-year period using a population-based linked dataset.

Between 1 April 1997 and 31 March 2008, 52 136 primary THRs, 8726 revision THRs, 44 511 primary TKRs, and 3222 revision TKRs were performed. Five years post-operatively, the rate of fracture was 0.9% after primary THR, 4.2% after revision THR, 0.6% after primary TKR and 1.7% after revision TKR. Comparison of survival analysis for all primary and revision arthroplasties showed peri-prosthetic fractures were more likely in females, patients aged > 70 and after revision arthroplasty.

Female patients aged > 70 should be warned of a significantly increased risk of peri-prosthetic fracture after hip or knee replacement. The use of adjuvant medical treatment to reduce the effect of peri-prosthetic osteoporosis may be a direction of research for these patients.

Introduction: Current evidence on the indications for and efficacy of non-rigid lumbar stabilisation remains unclear. The aim of this study was to review the results of this system in thirty four patients who underwent this procedure between 2002 and 2006.

Methods & Results: Validated outcome measures including Visual Analog Score (VAS), Roland Morris Disability Questionnaire (RMDQ), Modified Zung Score and Modified Somatic Perception Questionnaire (MSPQ) were evaluated preoperatively and at 1 year post operatively. Subjective patient outcome (much better, better, same, worse) was assessed at final followup Kaplan-Meier Survival analysis was performed using need for revision surgery as endpoint. The indications for surgery in thirty patients was radicular pain and back pain, these patients underwent discectomy (12 patients) or decompression (18 patients) in addition to Dynesys. Two patients who had only back pain underwent Dynesys alone. There were statistically significant improvements in VAS, RMDQ, Modified Zung and MSPQ scores at 1 year. However at final followup 46% of patients had a unsatisfactory subjective patient outcome (worse or the same). 25% of patients required revision surgery (posterolateral fusion) for ongoing pain (seven patients) or infection (one patient).

Conclusion: We recommend that all patients undergoing this procedure are counselled regarding the high rate of revision surgery and patient dissatisfaction. Routine use of this implant should be subject to the findings of larger studies and randomised controlled trials.

Ethics approval: None

Interest Statement: None

We investigated the excess mortality risk associated with fractures of the hip. Data related to 29 134 patients who underwent surgery following a fracture of the hip were obtained from the Scottish Hip Fracture Audit database. Fractures due to primary or metastatic malignancy were excluded. An independent database (General Register Office (Scotland)) was used to validate dates of death. The observed deaths per 100 000 of the population were then calculated for each group (gender, age and fracture type) at various time intervals up to eight years. A second database (Interim Life Tables for Scotland, Scottish Government) was then used to create standardised mortality ratios. Analysis showed that mortality in patients aged > 85 years with a fracture of the hip tended to return to the level of the background population between two and five years after the fracture. In those patients aged < 85 years excess mortality associated with hip fracture persisted beyond eight years. Extracapsular hip fractures and male gender also conferred increased risk.

We have investigated how medical postponement, the time to surgery and the correction of medical abnormalities, according to McLaughlin criteria, before operation affected peri-operative mortality after fracture of the hip. From February to December 2007, in addition to core data, the Scottish Hip Fracture Audit collected information relating to surgical delay. Data were available for 4284 patients which allowed 30-day survival analysis to be performed. Multivariable logistic regression models were used to control for differences in case-mix.

Patients with major clinical abnormalities were more likely to have a postponement and had a lower unadjusted 30-day survival. The time to operation and postponement were not associated with higher mortality after adjustment for case-mix. Correction of major clinical abnormalities before surgery improved the adjusted survival, but this improvement was not significant (p = 0.10). Postponement without correction of a medical abnormality before surgery was associated with a significantly lower (p = 0.006) 30-day adjusted survival. The possible benefits of postponement need to be weighed against prolonged discomfort for the patient and the possibility of the development of other complications.

Introduction: Treatment of dual compartment osteoarthritis remains controversial, with conjecture over whether Uni-Compartmental (‘UKA’) or Total Knee Arthroplasty (‘TKA’) is more appropriate for patients with patello-femoral disease. The ‘Journey Deuce’ 2/3 Knee Arthroplasty (‘2/3 Knee’) (Smith & Nephew) is a bi-cruciate retaining prosthesis designed to treat this subgroup of patients with both antero-medial and patello-femoral disease.

We have conducted a prospective, observational clinical trial of 34 patients with dual compartment osteoarthritis of the knee treated with a 2/3 Knee.

Aims: To assess the safety and clinical efficacy outcomes of the 2/3 Knee.

Method: All patients pre-op leg alignment films, as well as MRI or arthroscopy to confirm the inclusion criteria of dual compartment osteoarthritis with a preserved lateral compartment and intact cruciate ligaments. All operations were performed by a single surgeon (DW) using computer assisted surgery (CAS) and a minimally invasive technique (MIS) at a local university affiliated private hospital (HPH).

Exclusion criteria included obesity, inflammatory arthritis and a fixed flexion deformity > 10 degrees.

Subjective outcome measures included Oxford Knee Scores (OKS) and EQ-5D Scores. RSA beads were implanted at surgery to detect loosening, micro-motion and prosthesis wear. Gait analysis was conducted at 1 year post op in a subgroup of patients.

Results: Follow up ranged from 6 months to 2 years. There have been no early failures requiring complete revision. The first 23 knees (18 patients) did not have primary resurfacing of the patella. Some of these patients suffered palpable and audible patello-femoral crepitus, with a subgroup (17%, 4 knees-3 patients) having associated anterior knee pain. This subgroup had revision procedures to resurface their patellae with resolution of their symptoms. All subsequent patients have had primary patella resurfacing with no incidence of Significant crepitus or anterior knee pain.

The patients have recorded Significant improvement in their Oxford Knee Scores at 6 months (mean reduction all patients: 17.3, resurfaced 20).

Early RSA results have not detected Significant migration to indicate early loosening. Gait analysis has shown that patients return to approximate normal rather than pre-operative gait.

Conclusions: Although longer follow up is required the 2/3 Knee appears a safe and effective treatment option for patients with dual-compartment osteoarthritis; with rehabilitation, function and gait tending towards that seen in UKA rather than TKA.

It is essential that patients undergo primary patella resurfacing to prevent crepitus and associated anterior knee pain.

A study comparing clinical outcomes of 2/3 Knee vs TKA is underway at our institution.

Introduction: Current evidence on the indications for and efficacy of non-rigid lumbar stabilisation remains unclear. The aim of this study was to review the results of this system in thirty four patients who underwent this procedure between 2002 and 2006.

Methods & Results: Validated outcome measures including Visual Analog Score (VAS), Roland Morris Disability Questionnaire (RMDQ), Modified Zung Score and Modified Somatic Perception Questionnaire (MSPQ) were evaluated preoperatively and at 1 year post operatively. Subjective patient outcome (much better, better, same, worse) was assessed at final followup Kaplan-Meier Survival analysis was performed using need for revision surgery as endpoint. The indications for surgery in thirty patients was radicular pain and back pain, these patients underwent discectomy (12 patients) or decompression (18 patients) in addition to Dynesys. Two patients who had only back pain underwent Dynesys alone. There were statistically significant improvements in VAS, RMDQ, Modified Zung and MSPQ scores at 1 year. However at final followup 46% of patients had a unsatisfactory subjective patient outcome (worse or the same). 25% of patients required revision surgery (posterolateral fusion) for ongoing pain (seven patients) or infection (one patient).

Conclusion: We recommend that all patients undergoing this procedure are counselled regarding the high rate of revision surgery and patient dissatisfaction. Routine use of this implant should be subject to the findings of larger studies and randomised controlled trials.

The purpose of this study was to assess the accuracy of a modified version of the pivot shift test in detecting ruptures of the anterior cruciate (ACL) ligament.

Methods: Two groups of patients aged 18 to 50 years were recruited from operating theatre lists examined at a check and consent clinic. One of the groups had ACL deficient knees and the control group had intact ACL, later proven at arthroscopy. A total of 48 independent examinations, 26 with ACL rupture and 22 without, were undertaken by a consultant or registrar proficient in the modified version of the pivot shift test. At the start of the consultation the examiner, who was blinded to the operation that the patient was listed for and to the patient’s history, performed the modified pivot shift test only. The result of the test was reported as positive or negative for ACL rupture to the study co-ordinator before the examiner continued with the consultation.

Results: Of the 26 examinations of ACL deficient knees, 22 were reported as positive and four negative for ACL rupture using the pivot shift test only. Of the 22 examinations of ACL intact knees one was reported as positive for ACL rupture and 21 as negative. This gives a specificity and sensitivity of the modified version of the pivot shift test as 95.5% (95% CI 75.1–99.8%) and 84.6% (95%CI 64.3–95.0%) respectively.

Conclusion: The modified pivot shift test is an accurate test for the detection of ACL rupture. Our modified pivot shift test compares favourably with data from previous accuracy studies of previously described versions of the pivot shift test. We now plan to assess the accuracy of the modified pivot shift test when carried out by medical students and junior doctors.

Objectives: To compare the results of various surgical approaches to the knee in primary arthroplasty surgery.

Design: Systematic review with meta-analysis

Data Sources: Cochrane Bone, Joint, and Muscle Trauma group trials register (2007), Cochrane central register of controlled trials (Cochrane Library issue 2, 2007), Medline (1950 to February 2007), Embase (1974 to February 2007), CINAHL (1982 to February 2007), Pubmed, SCOPUS and ZETOC. If data was insufficient trialists were contacted via telephone, email or letter.

Review methods: Randomised and quasi-randomised controlled trials comparing surgical approaches to the knee in patients undergoing primary arthroplasty surgery.

Results: Twenty-three randomised, controlled trials (1282 patients, 1490 TKAs) were included.

Midvastus vs Medial Parapatellar approach: Quadriceps function in the early post operative period was better preserved in the MV group. Post operative pain, blood loss and the need for LRR tended to be lower in the MV group. There was no difference in ROM, hospital stay, knee scores, complications or radiological alignment.

Conclusions: Approaches preserving the quadriceps tendon improve the early extensor mechanism function and tend to decrease the need for LRR. Combined with a decrease blood loss and postoperative pain, these approaches improve early rehabilitation and allow for a more rapid recovery of knee function. However, these early improvements fail to provide any long term benefit, do not improve knee scores, or decrease the length of hospital stay.

Introduction: Tendon injury is an important cause of injury in racehorses, with flexor tendon and suspensory ligament injuries accounting for 46% of all musculoskeletal injuries at British racecourses (1). In the galloping horse the superficial digital flexor tendon (SDFT) undergoes strains that are close to the functional limit of the tendon (2) and it is hypothesised that exercise induces cumulative microdamage in the SDFT of skeletally mature horses which may predispose to clinical disease. We hypothesised that matrix metalloproteinases (MMPs) play a role in the process of tendon degeneration induced by cyclical loading and investigated this using an in vitro model.

Methods: Mid-metacarpal SDFTs were harvested from Thoroughbred horses that were euthanased for non-orthopaedic reasons. Tendon explants (2mm x 2mm x 60mm) were maintained in DMEM and placed in custom designed loading cassettes which were cyclically loaded in an incubator using a Dartec materials testing device for 24 hours with 5% strain and at a frequency of 1Hz. Control explants were placed in similar cassettes but were not loaded. The ultimate tensile strength (UTS) of the tendon was assessed using a destructive test at the end of the 24 hour loading period. The experiments were repeated using non-viable tendon explants, or in the presence of a pan-MMP specific inhibitor (Illomastat, 25 μM).

Results: Cyclical loading induced a 30% decrease in the UTS of tendons of immature and young mature (< 10 years of age) horses but this increased to a 50% reduction in older (10–30 years of age) horses compared to controls. This loss of UTS was prevented in tendon explants with non-viable cells or with a pan-MMP inhibitor applied to the live explants prior to cyclical loading.

Conclusions: The results suggest that an MMP mediated mechanism plays a pivotal role in tendon degeneration following cyclical loading in vitro. Current work including analysis of gene expression and quantification of MMPs within the tendon tissue aims to identify the key MMPs responsible for the loss of tendon UTS following cyclical loading. This will hopefully enable therapeutic strategies to be developed to slow or stop the age-associated tendon degeneration that predisposes to overstrain injury, and thereby help prevent this common orthopaedic disease in horses.

We investigated the relationship between a number of patient and management variables and mortality after surgery for fracture of the hip. Data relating to 18 817 patients were obtained from the Scottish Hip Fracture Audit database. We divided variables into two categories, depending on whether they were case-mix (age; gender; fracture type; pre-fracture residence; pre-fracture mobility and ASA scores) or management variables (time from fracture to surgery; time from admission to surgery; grade of surgical and anaesthetic staff undertaking the procedure and anaesthetic technique).

Multivariate logistic regression analysis showed that all case-mix variables were strongly associated with post-operative mortality, even when controlling for the effects of the remaining variables. Inclusion of the management variables into the case-mix base regression model provided no significant improvement to the model. Patient case-mix variables have the most significant effect on post-operative mortality and unfortunately such variables cannot be modified by pre-operative medical interventions.

Objective: To challenge the validity of using biomarker concentrations in synovial fluid for the assessment of joint pathology.

Hypothesis: Synovial fluid biomarker concentrations are influenced by both cartilage and synovial fluid volumes.

Methods: Synovial fluid volumes were determined from the equine metacarpophalangeal (MCP), proximal inter-phalangeal (PIP) and distal interphalangeal (DIP) joints, which have different disease prevalences.

Chondrocyte density was calculated from a defined site in each joint.

Cartilage volume was measured by novel application of Peripheral Quantitative Computed Tomography (pQCT).

Cartilage oligomeric matrix protein (COMP), glycos-aminoglycans (GAG) and total protein (TP) concentrations were measured and then adjusted for cartilage and synovial fluid volume and compared between joints.

Results: Mean synovial fluid volume was significantly greater in the MCP than the distal joints (p< 0.0001) (3.2 ±0.5ml, 0.5 ±0.1ml and 0.6 ±0.1ml respectively). In contrast, the DIP had the greatest cartilage volume compared to the proximal joints (5360 ±667mm3 2640mm3, 1940 ±331mm3 respectively). There was no significant difference in the cartilage cellularity between all joints.

The DIP had higher TP, COMP and GAG concentrations, however, when values were expressed per unit cartilage volume the opposite was found, with the MCP then exhibiting significantly higher concentrations.

Conclusions: These data show the joint with the highest prevalence to osteoarthritis has the lowest biomarker synovial fluid concentrations but the highest biomarker levels per unit cartilage, suggesting a higher release. These results indicate that meaningful interpretation of biomarkers in synovial fluid require consideration of both fluid and cartilage volume.

We aim to assess the outcome of ankle arthrodesis performed for painful osteoarthritis in the presence of a coronal plane deformity of 20 degrees or more. To our knowledge this is the first reported series of such a cohort of patients. We have a consecutive and complete series of 24 patients with 26 ankle arthrodeses which were all performed for painful osteoarthritis in the presence of large coronal plane deformity. These patients have a minimum of twelve months clinical follow up. The results showed a low non union rate of 8% (2 ankles). These have subsequently been refused satisfactorily, and were excluded from further analysis. The results of the remaining 24 ankles which united primarily show that they were very pleased with the outcome of their surgery. AOFAS scores were used to measure pain and function both pre operatively and post operatively. These scores showed large improvements for both pain and function, and had a high statistical significance (p< 0.0005). All patients improved in their walking distance and many patients reduced their need for walking aids. Stair climbing ability was also improved in some patients. It is recognised that an ankle arthrodesis usually relieves pain but does not result in a normal gait and full function. We feel that the high level of patient satisfaction in this series was due to the combination of deformity correction, restoring a functional foot position, and achieving a painless ankle. Arthroplasty of the ankle is a good procedure for relief of pain and restoration of function. However In the presence of a large coronal plane deformity ankle arthroplasty is known to fare badly with early failure. Therefore for patients with painful osteoarthritis and a coronal plane deformity of 20 degrees or more, we recommend ankle arthrodesis as the procedure of choice.

We report gender differences in the epidemiology and outcome after hip fracture from the Scottish Hip Fracture Audit, with data on admission and at 120 days follow-up from 22 orthopaedic units across the country between 1998 and 2005. Outcome measures included early mortality, length of hospital stay, 120-day residence and mobility. A multivariate logistic regression model compared outcomes between genders. The study comprised 25 649 patients of whom 5674 (22%) were men and 19 975 (78%) were women. The men were in poorer pre-operative health, despite being younger at presentation (mean 77 years (60 to 101) vs 81 years (50 to 106)). Pre-fracture residence and mobility were similar between genders.

Multivariate analysis indicated that the men were less likely to return to their home or mobilise independently at the 120-day follow-up. Mortality at 30 and 120 days was higher for men, even after differences in case-mix variables between genders were considered.

We prospectively studied 29 patients with distal femoral fractures stabilised using the less invasive stabilisation system [LISS]. Four patients were excluded from the final follow up [3 deaths and 1 case of quadriplegia]. The mean age of the remaining 25 patients [9 males] was 60.9 years and the mean follow up 18 months [12–24]. Eleven patients were tertiary referrals from other hospitals [7 cases were referred due to failure of primary fixation]. Overall, there were 12 cases of high-energy trauma [7 open fractures]. According to the AO classification there were 5 Type 33A, 2 Type 33B and 12 Type 33C fractures and 4 Type 32A, 1 Type 32B, 1 Type 32C fractures. Functional assessment was performed using the Modified HSS and the Schatzker and Lambert scores. The average time to union in 22 cases was 3.5 months [range, 2–5]. None of the acute cases required bone grafting with a 100% union rate. There were 3/7 cases of non-union in the salvage group still undergoing treatment. The overall results in the acute cases were good and in the salvage cases fair. While this is a small series of patients, our preliminary data indicate favourable results using the LISS in stabilizing acute distal femoral fractures. However, when the LISS is used as a revision tool despite the concept of preserving the bone biology, the results seem to be less satisfactory. The system appears to be user friendly and no technical difficulties were encountered.

The application and interpretation of the impact factor of a journal is fraught with problems, some of which are explored in this editorial.

A consecutive series of 23 patients (25 ankles) with osteoarthritis of the ankle and severe varus or valgus deformity were treated by open arthrodesis using compression screws. Primary union was achieved in 24 ankles one required further surgery to obtain a solid fusion. The high level of satisfaction in this group of patients reinforces the view that open arthrodesis, as opposed to ankle replacement or arthroscopic arthrodesis, continues to be the treatment of choice when there is severe varus or valgus deformity associated with the arthritis.

Introduction: Energy storing tendons, such as the human Achilles tendon, suffer a much higher incidence of rupture than non- energy storing positional tendons, such as the anterior tibialis tendon. Similarly, in the horse partial rupture of the energy storing superficial digital flexor tendon (SDFT) and suspensory ligament (SL) occurs much more frequently than to the deep digital flexor tendon (DDFT) and common digital extensor tendon (CDET) which are not involved in energy storage. In order to function effectively, energy storing tendons experience strains during high speed locomotion which are much closer to failure strain than non-energy storing tendons. Therefore, these tendons are likely to sustain high levels of microdamage, hence cell metabolism may also be higher in order to repair damage and maintain matrix integrity. Maintenance of the matrix requires not only synthesis of new matrix components but also degradation of matrix macromolecules which is achieved, in part, by a family of matrix metalloproteinase enzymes (MMPs). In this study we test the hypothesis that the energy storing equine SDFT and SL which are prone to degenerative changes have higher levels of MMP2 and MMP9 than the positional DDFT and CDET that are rarely injured.

Methods: Tendons (SDFT, DDFT, SL, CDET) were harvested from the distal part of the forelimbs of 18 month old Thoroughbred horses (n = 12). Tissue from the mid-metacarpal region of each tendon was snap frozen, lyophilised, powdered and MMPs extracted. Gelatin zymography was used to determine levels of the pro and active forms of the gelatinase enzymes, MMP2 and MMP 9. Proteolytic activity (units per mg dry weight tissue) was quantified based on densitometry measurements and standardised between gels using an equine neutrophil MMP extract. Statistical significance was evaluated using a general linear model (SPSS software).

Results: The main activity observed in all tendon samples was that of proMMP2. Quantification showed that the energy storing SDFT (23.4 ± 10.95) and SL (18.9 ± 5.3) had significantly higher levels than the non-energy storing DDFT (2.90 ± 0.99) and CDET (4.06 ± 2.06). Active MMP2 levels were lower than the pro form and were not sufficient to quantify. However, there appeared to be more in the energy storing structures compared with the non energy storing structures. MMP9 activity was detected in some samples. A higher number of the CDET extracts contained MMP9 activity compared to extracts from the other structures.

Discussion: The results of this study show higher levels of MMPs in energy storing structures than in non-energy storing structures. This suggests that there may be an increased demand for repair of micro-damage in these tendons and hence an increased capacity for matrix degradation. Previous studies on energy storing structures in the horse have shown that they do not undergo adaptive hypertrophy or a change in structural architecture in response to mechanical demand, unlike non-energy storing structures. The results of this study indicate that this lack of adaptation in energy storing structures is not due to a general deficiency in cell activity but may be a means of preventing increase in tendon stiffness and a subsequent decrease in efficiency. In order to maintain tendon integrity MMP activity must be matched by mechanisms to inhibit activity and/or to synthesize new matrix components. Degeneration may therefore occur when there is an imbalance between these processes.

Background: To assess the cosmetic advantage of costotomy at the angle of the ribs on the convexity of a curve in the management of Adolescent Idiopathic scoliosis. Whilst modem segmental correction produces gratifying improvement in Cobb-angle and, to some extent rotation, rib asymmetry often remains as a concern for patients. Performing costotomy at the angle of the rib at the same time as corrective surgery can improve the cosmetic appearance significantly. It avoids any further scars or surgery, and is associated with minimal complications, the main one being pneumothorax and the requirement of a chest drain.

Methods: Retrospective review of 50 patients. This has been a standard practice and this presentation reports on 50 patients treated in Preston with a variety of corrective devices; we have assessed results radiologically, with cosmetic acceptability by the patient and surface topographical analysis.

Results: Significant improvement occurs at the time of costotomy as the ribs drop from their arched position after the coronal deformity has been improved

Conclusion: The addition of costotomy at the time of primary surgery for Adolescent Idiopathic Scoliosis leads to minimal complications. Significant improvement occurs at the time of costotomy as the ribs drop from their arched position after the coronal deformity has been improved. This is maintained in the post-operative period by moulding of the brace.

We have performed a prospective review of 590 consecutive patients treated for a displaced intracapsular femoral neck fracture with a Thompson hemiarthroplasty. 113 patients had the prosthesis cemented, 477 had no cement. The outcome at 12 months was obtained for every patient still alive as regards to pain, mobility, re-operation rate and residential status. There was no significant difference between the 2 groups as regards pain (p = 0.482), decrease in mobility or re-operation rate (p = 0.168). The main determination of poor outcome was increasing age at time of injury and whether the patient was already in institutional care at the time of the injury. The use of cement had no bearing on outcome.

This study is of clinical interest because patients who have undergone uncemented hemiarthroplasty have been shown to have similar out come to cemented hemiarthroplasty in terms of function. In addition possible but preventable complications associated with cementing can be minimized. We now believe there is no primary indication to cement the Thompsons hemiarthroplasty in this group of patients.

There have been smaller studies looking at this, but we believe this to be the largest and most comprehensive to date.

Introduction and Aims: Prospective review of the patients who underwent stabilisation of displaced acetabular fractures in our unit in order to evaluate the presence of neurological lesions and functional outcome.

Method: Out of 136 patients operated over six years we identified 27 patients with neurological lesions. A standard protocol was followed for the clinical and neurophysiological evaluation of nerve injuries. Electromyography (EMG) was used to determine the anatomical location of the neurological lesions and the type of lesion, which act as a valuable tool in the diagnosis of double crush lesion in the sciatic nerve. Neurological recovery was evaluated with EMG studies and clinically rated as described by Clawson et al. Functional outcome was graded by the system proposed by Fassler and Swiontkowski.

Results: EMG studies revealed sciatic nerve lesions in all the cases. Additionally, in nine patients with a dropped foot there was evidence of a proximal (sciatic notch) and distal (neck of fibula) lesion – ‘double crush syndrome’. At final follow-up, clinical examination and associated EMG studies revealed full recovery in five cases with initial muscle weakness, and complete resolution of sensory symptoms (burning pain, hyposthesia) in four cases. There was improvement of functional capacity (motor and sensory) in two cases with initial complete drop foot and in four cases with muscle foot weakness. In 11 of the cases with dropped foot (all nine with double crush) at presentation, there was no improvement in function. Functional outcome was unsatisfactory in all patients with double crush injury.

Conclusion: In cases where there is evidence of ‘double crush lesions’ the prospect of functional recovery is low as seen in this group of patients. The patients with double crush syndrome are not expected to recover and could be considered as a sign of unfavourable outcome following neurological impairment after acetabular fractures. Single lesions appear to be associated with a more favourable prognosis.

We aim to assess the value of patellofemoral Computed Tomography in assessing patients with anterior knee symptoms. Anterior knee symptoms are often due to patellar malalignment. Plain axial radiography or (CT) can be used to investigate these abnormalities. We have evaluated the use of patellofemoral CT scanning in 63 patients and compared the CT findings with the patients’ symptoms. We compared patellar centralisation and patellar tilt angle with the symptom described for each of 126 knees. No difference could be detected in the CT appearances of affected and unaffected knees in those patients with unilateral symptoms (all patients have both knees scanned). A significant association between maltracking and osteoarthiritic changes was demonstrated.

Aims: To study the outcome of lumbar spinal fusions in patients with chronic lower back pain due to degenerative spinal disorders. Methods: 85 patients with DSD’s, a mean age of 46.4 years, back pain for at least 2 years (mean=7.7years) and failed conservative treatment for at least 1 year were admitted to the study. Questionnaires recorded socio-demographic characteristics; changes in pain, clinical findings, disability (Oswestry (ODI)), employment, radiographic fusion, patient satisfaction and complications. All patients had 3, 6, 12 and 24-month follow-ups. Results: There were 37 males (44.9years) and 48 females (47.6 years) with a mean BMI of 24.8; 49% were smokers. Pain improved significantly at 3months (p< 0.001); no deterioration at 2 years with 38.4% having no back pain. Motor (p< 0.01), sensory (p< 0.05) and Oswestry Disability (0.001) improved significantly at 3 months and continued throughout. Unemployment improved significantly 30.4% to 16.5% at 2 years (p< 0.04). Radiographic fusion occurred in 91.8%, instrument failure in 11.8% and 9.4% required re-operation. Patient satisfaction revealed a significant increase in excellent (p< 0.02) and poor (p< 0.03) results. Instrument failure correlated strongly with ODI (r=0.94, p< 0.04). No other significant correlations. Conclusions:With the correct patient selection, lumbar fusions for DSD’s lead to a significantly improved outcome at 2 years, with an acceptable complication rate. There is no correlation between radiographic fusion and outcome, but instrument failure leads to significantly worse outcome

Aims: To investigate the functional outcome with different autologous bone graft weights in posterolateral lumbar spine instrumentation for DSD’s. Methods: A total of 79 patients (mean age of 47.2) with chronic lower back pain for at least 2 years, with at least 1 year of failed conservative treatment and who were undergoing pos-terolateral spinal instrumentation for DSD’s were admitted to the trial. Patients were randomised into three groups to receive bone graft weights of 25g (Group A=26 patients), 50g (Group B=30 patients) and 100g (Group C=23 patients) per segment. Pain, clinical characteristics, disability (Oswestry), radiographic fusion, patient satisfaction and complications were recorded at 3, 6, 12 and 24-month follow-ups. Results: At 2 years, Group B (50g) had a significantly improved Oswestry Index, pain intensity, motor and sensory changes, and overall patient satisfaction than Group C (100g), which was significantly better than Group A (25g). There was no correlation between bone graft weight and radiographic fusion, between fusion and outcome, nor smoking and fusion or bone graft weight. Complications were similar. Conclusions: Patients had significantly better functional and clinical outcomes with bone graft weights of 50g. Bone graft weights of 25g had the worse outcomes and 100g did not seem to have any beneficial affect over 50g. We recommend autologous bone graft weights of 50g per fused spinal segments in this group of surgical patients.

Aims: We performed a prospective study on 105 knees following a selective approach to patellar resurfacing in cruciate retaining total knee replacements, and report the þve year results of both groups. Methods: We performed a prospective study on 129 knees with a selective approach to patellar resurfacing. 105 knees were followed up at an average of 57 months. Of these, forty eight knees met the eligibility criteria, thus leaving 57 knees with unresurfaced patellas. Mean follow up was 57 months. Parameters studied included HSS scores, pain, function, range of motion and patellofemoral symptoms including the ability to rise from a chair and to negotiate stairs. Results: Approximately 90% good to excellent results were observed in both groups. The incidence of anterior knee pain and patellofemoral related problems was lower than the average reported in literature. None of the knees was revised for patellofemoral problems. Conclusions: Our þndings suggest that the results of patellofemoral resurfacing with modern TKR designs are dependent on a careful patient selection and meticulous surgical technique. With a selective approach to resurfacing, one can achieve a high percentage of good results in both groups. Post operative anterior knee pain is probably not related to the fact as to whether the patella is resurfaced or not.

Aim: We have reviewed the patients treated in our institution with vertical shear fractures of the pelvis and report on our treatment protocol and long term functional outcome. Methods: Between Jan 1993 and Jan 2002 patients with vertical shear fractures were identiþed. Data such as age, sex, aetiology, associated injuries, ISS, resuscitation requirements, transfusion requirements, ICU/HDU stay, treatment, urological injuries, systemic complications, neurological injury and mortality were recorded and analysed. Functional outcome assessment was performed using the following generic tools: Euro-qol 5D (EQ), SF36 v2 (Short form), SMFA, Majeed score and VAS. Results: Out of 380 pelvic ring injuries we identiþed 31 vertical shear fractures in 29 consecutive patients (4 female). The median ISS Score was 22. Motorcycle accidents were responsible for 27%. Injuries were identiþed in the chest (12 patients), abdomen (8 patients) and extremities (14 patients). Urethral injury was present in 9 patients. Ruptured viscus was identiþed in 3 cases. At presentation neurologic deþcit was present in 9 cases. Posterior ring was stabilised in 3(0–13) days. Systemic complications developed in 6 patients Ð ARDS in 4 patients and sepsis in 2 (6%). The mean follow up was 39 months. Functional outcome using the Majeed score revealed that 1/3 of the patients did fair. TheSF-36 v2 analysis, EQ 5-D revealed a moderate functional outcome. The SMFA and the visual analogue score also revealed similar outcomes. Conclusions: Prompt resuscitation and early temporarily stabilisation of the pelvic ring is essential. Sound reconstruction of the pelvic ring is not always associated with good results probably due to the extensive pelvic ßoor trauma as seen in this series of patients. Younger individuals seem to have a relatively better outcome when compared to the older age group.

Aims: To identify the incidence of neurological deþcit and functional outcome following displaced acetabular fractures. Methods: We carried out a prospective study of 136 patients who underwent skeletal stabilization of displaced acetabular fractures. Patients with sciatic nerve injuries were identiþed, assessed and followed up clinically. Routine EMG and nerve conduction studies were performed post-operatively on all cases with clinical proven neurological lesions to correlate the level, severity of the lesion and monitor progress of recovery. Results: 27 patients (19.8%) have neurological deþcit identiþed preoperatively. In 12 patients where the femoral heads were dislocated posteriorly. 20 were male and 7 were female. The mean age was 33.8 years (range 16–66). 15 patients had associated injuries but none of the patients had injury to the spinal cord. The mean ISS was 12.6 (range 9–34). The mean follow up was 3.4 years (range 1.5–6 years). 13 patients with complete drop foot at presentation. 9 patients had EMG proven double crush lesion. 3 patients had ipsilateral knee injury. 2 patients had intraopearative iatrogenic injury. All 9 patients with double crush syndrome have no improvement in function. Conclusions: Acetabular fractures associated with sciatic nerve injuries are devastating injuries with signiþcant long term morbidity. 50% patients showed improvement with time. Identiþcation of double crush lesion is vital as it is associated with poorer functional recovery as compared to single lesion.

To evaluate the results of management of urological injury and the impact on final outcome in patients with pelvic fractures.

Out of 554 patients with pelvic fractures, 39 (7%)(8 female) were identified with urinary tract injuries. The mean age of the patients was 30.9 yrs (range 15–71) and the mean ISS was 12.9 (range 9–22). Seven (18 %) had upper tract injury, 6 (15.4 %) had extraperitoneal bladder rupture, 9 (23.1 %) had intraperitoneal rupture, 3 (7.6 %) had bladder neck injury and 14 (35.9 %) had urethral injury. Timing of urological intervention, complications and long term result in terms of incontinence, stricture and sexual dysfunction were assessed. All patients were assessed based on Orthopaedic, urological and the Euroqol (EQ5D) generic health questionnaire and compared to age and sex matched control group of 47 patients with similar pelvic injuries and ISS but no urological injury. The mean follow up period was 2.3 years.

Upper urinary tract injuries: All were managed non-operatively and had a uniformly good outcome except one patient who had a traumatic renal vein thrombosis and required nephrectomy.

Lower tract injuries: 14 out of 15 patients with bladder rupture had a repair of bladder within 24 hours of arrival at our center. One with a small extraperitoneal tear was managed nonoperatively. Three patients reported failure of erection. Two were managed by immediate repair (day 1 and day 2) and had normal continence. One repair was delayed due to delay in transfer and was done on the 4th day. He developed faecal and urinary incontinence and loss of sexual function.

Thirteen males had urethral injury. Three patients had a primary urethrostomy for a gap defect and two of these developed erectile dysfunction. Two were referred late to our center and were managed by continent urinary diversion. The rest had a catheter railroaded to maintain alignment of the two urethral ends and delayed repair was done for three patients. One patient in this group had sexual dysfunction while 5 developed a stricture.

We found no significant difference between the study and the control group in the outcome on comparing patients with upper tract and bladder injuries but the urethral injury group had a poorer result in all 5 parameters of the EQ5D.

Upper tract and bladder injuries do not add significant morbidity compared to the control group. In contrast urethral injuries significantly affected the outcome after pelvic fracture in terms of general health and return to normal function.

The U-shaped sacral fracture is a fracture pattern poorly recognized, that is not included in the standard classification of sacral fractures. These fractures are significant as they represent spino-pelvic dissociation, have a high incidence of neurological complications and information regarding modern treatment options is sparse. A number of authors have reported isolated cases or small series of patients with this type of fracture, although none explicitly note the bilateral vertical element that makes them U-shaped and represents spino-pelvic dissociation.

We present four patients with U-shaped sacral fractures. All patients were polytraumatised patients of whom three had jumped from a height in suicide attempts illustrating the high energy required to produce this fracture.

Three patients had ilio-sacral screw fixation, supplemented in one with instrumentation from the lumbar spine to the iliac crest. The other had sacral laminectomy with bony stabilization by instrumentation from the lumbar spine to the iliac crest without ilio-sacral screw fixation.

No complications were encountered as a result of fixation. The fixation devices used essentially represent the local expertise that is available. The ilio-sacral screw technique is minimally invasive and appears to provide satisfactory fixation in our limited experience. However as fracture deformity often involves rotation of the upper sacrum, the use of a single screw may not provide adequate support against the deforming forces or allow reduction of the fracture. Additional ilio-sacral screws will provide some rotational control of the sacral fragment if their safe insertion is possible, if not then the forces should probably be neutralized by an additional device from L5 to the pelvis.

The role of sacral decompression is unclear but may be appropriate in the presence of neurological deficit and a severely compromised sacral canal.

These are complex, rare injuries. We recommend their referral to a specialized pelvis/spinal unit for definitive management.

The clinical features, investigation, treatment and outcome of two adults with fibrogenesis imperfecta ossium are described. In this rare acquired disorder of bone, normal lamellar collagen is replaced by structurally unsound collagen-deficient tissue, which leads to extreme bone fragility and ununited fractures. Transmission microscopy and SEM showed striking ultrastructural changes in bone structure and mineralisation. Both patients had monoclonal IgG paraproteins in the plasma and one excreted monoclonal lambda light chains in the urine. No abnormal plasma cells were found in the bone marrow and there was no evidence of amyloid deposition in the tissues. In both patients initial treatment with 1 alpha-hydroxycholecalciferol appeared to be ineffective, but in one, repeated courses of melphalan and corticosteroids over three years together with 1 alpha-hydroxycholecalciferol produced striking clinical and histological improvement. The findings in these and other patients strongly suggest that paraproteinaemia is an integral feature of fibrogenesis imperfecta ossium, and this needs further investigation.

Progressive structural scoliosis in growing rabbits has been produced. Tethering the thoracic spine into the form of an asymmetric lordosis produces a slowly progressive structural scoliosis by purely mechanical means. The addition of a contralateral release of the paraspinal muscles leads to a very progressive deformity with early cardiorespiratory failure. This release, however, was performed with an electric soldering iron and subsequent study showed that in those animals with severe progressive deformity there was localised spinal cord damage. We suggest that it is this neural damage and not the muscle release which leads to rapid progression. The clinical implications are important in that neurological dysfunction seems to render the spinal column less able to resist mechanical buckling and may be the crucial factor differentiating severely progressive from more benign curves.

One hundred and twenty-five patients with 194 feet affected by congenital talipes equinovarus were treated by the senior author during the period 1959 to 1980. Of these, 70 patients presented either at birth or in the early neonatal period, and 55 were seen later, having been referred from other centres. Seventy-five patients were subsequently reviewed by two of us; the remaining 50 were assessed from records and research files. Patients seen within four weeks of birth were termed "early", the remainder "late". Of the early group of 70 patients, 44 (with 68 affected feet) were reviewed and 26 (with 41 affected feet) were assessed from records. Excellent or good results were achieved in 94 per cent of feet treated conservatively and in 82 per cent of feet which required pantalar release. Of the 55 late referrals 32 patients (with 55 affected feet) were reviewed and 23 (with 30 affected feet) were assessed from records. Satisfactory results were slightly less frequent, but were achieved in 75 per cent of cases. There was no statistical correlation between early soft-tissue release and a good final outcome, but there was a positive statistical correlation between good clinical results and a high talocalcaneal index. Osseous correction (a laterally based wedge tarsectomy or a triple arthrodesis) was necessary at a later date in four feet (four per cent) of those who presented early and in 13 feet (15 per cent) of late referrals.

Six patients are described with idiopathic osteoporosis which began between the ages of 4 and 16 years. In four children the disorder was mild with pain in the back, vertebral collapse, qualitatively normal iliac bone biopsies, variable calcium balance and spontaneous recovery. The two remaining patients had progressive bone disease with deformity. One with a previously normal skeleton developed changes similar to those of osteogenesis imperfecta; in the other patient, who rapidly developed structural collapse associated with severe metaphysial osteoporosis, treatment was ineffective and the histological appearances of the bone suggested osteoblastic failure. Quantitative bone histology in four patients showed no evidence of excessive active resorption; and the ratio of Type III to Type I collagen in the skin was normal, in contrast to the findings in osteogenesis imperfecta. The significance of this study in relation to previous accounts is reviewed.

The clinical features of eight patients with myositis ossificans progressiva are described and the effects of treatment with the diphosphonate EHDP, together with surgical removal of ectopic bone, are assessed. Early correct diagnosis remains unusual, mainly because the significance of the short great toes is unrecognised, and because myositis may be mistaken for bruising, sarcoma or mumps. The diphosphonate disodium etidronate (EDHP) was given to all patients in an attempt to suppress calcification of new lesions; in five of them ectopic bone was removed during the treatment. EHDP sometimes delayed the mineralisation of newly formed bone matrix after surgical removal but this delay could not be predicted. The variable effect of EHDP may depend particularly on the amount absorbed and on the activity of new bone formation.

In a clinical, radiological and biochemical study of forty-two patients from Oxford with osteogenesis imperfecta, it was found that patients could be divided simply into mild, moderate and severe groups according to deformity of long bones. In the severe group (seventeen patients) a family history of affected members was uncommon and fractures began earlier and were more frequent than in the mild group (twenty-two patients); sixteen patients in the severe group had scoliosis and eleven had white sclerae; no patients in the mild group had white sclerae or scoliosis. Radiological examination of the femur showed only minor modelling defects in patients in the mild group, whereas in the severe group five distinct appearances of bone (thin, thick, cystic and buttressed bones, and those with hyperplastic callus) were seen. The polymeric (structural) collagen from skin was unstable to depolymerisation in patients in the severe group, but normal in amount, whereas the reverse was found in the mild group. This division according to long bone deformity may provide a basis for future research more useful than previous classifications.

1. The phosphonates are simple chemical compounds containing P-C-P bonds which are resistant to the action of naturally occurring phosphatases and pyrophosphatases. They inhibit the formation and dissolution of apatite crystals in vitro and prevent ectopic mineralisation and bone resorption in animals.

2. In man one diphosphonate (EHDP) has been shown to reduce the excessive turnover of bone in Paget's disease and also appears to slow the mineralisation of ectopic bone matrix in myositis ossificans progressiva.

3. The possible uses of the diphosphonates in bone disorders with excessive resorption and in ectopic mineralisation are being further investigated.