This study evaluates the association between consultant and hospital volume and the risk of re-revision and 90-day mortality following first-time revision of primary hip replacement for aseptic loosening.

We conducted a cohort study of first-time, single-stage revision hip replacements (RHR) performed for aseptic loosening and recorded in the National Joint Registry (NJR) data for England, Wales, Northern Ireland, and the Isle of Man between 2003 and 2019. Patient identifiers were used to link records to national mortality data, and to NJR data to identify subsequent re-revision procedures. Multivariable Cox proportional hazard models with restricted cubic splines were used to define associations between volume and outcome.

Among 12,676 RHR there were 513 re-revisions within two years, and 95 deaths within 90 days of surgery. The risk of re-revision was highest for a consultant's first RHR (Hazard Ratio (HR) 1·58 (95%CI 1·16 to 2·15)) and remained significantly elevated for their first 26 cases (HR 1·26 (95%CI 1·00 to 1·58)). Annual consultant volumes of five/year were associated with an almost 30% greater risk of re-revision (HR 1·28 (95%CI 1·00 to 1·64)) and 80% greater risk of 90-day mortality (HR 1·81 (95%CI 1·02 to 3·21)) compared to volumes of 20/year. RHR performed at hospitals which had cumulatively undertaken fewer than 168 RHR were at up to 70% greater risk of re-revision (HR 1·70 (95% CI 1·12 to 2·60)), and those having undertaken fewer than 309 RHR were at up to three times greater risk of 90-day mortality (HR 3·06 (95% CI 1·19 to 7·86)).

This study found a significantly higher risk of re-revision and early postoperative mortality following first-time single-stage RHR for aseptic loosening when performed by lower-volume consultants and at lower-volume institutions, supporting the move towards the centralisation of such cases towards higher-volume units and surgeons.

Elevated synovial leukocyte count is a minor criterion derived from the musculoskeletal infection society (MSIS) widely used in clinical practice for diagnosis of prosthetic joint infection. There is evidence to suggest analysis within 1 hour, preferentially within 30 minutes, of aspiration reduces the risk of ex vivo cell lysis occurring during prolonged transport. Multiple site working is more common practice and the availability of a lab on site to perform these tests is not always possible. We aimed to assess whether we could safely perform synovial leukocyte counts within our cold site in the diagnosis of prosthetic joint infection.

We reviewed all orthopaedic synovial fluid aspirates within the lower limb arthroplasty unit from April 2021 – April 2022 performed at South Tees NHS Foundation Trust. We assessed time from aspirate to the lab using electronic data resources. This information was compared with the labs ability to perform a synovial leukocyte count to determine the impact of delays on testing.

110 patients (34.5% hips and 63.6% knees) were identified between two sites. Time from aspirate to lab ranged from 0 mins to 26 hrs 34 mins. Mean time to processing was 3hrs 10 mins. 50% of all samples had a synovial leukocyte count performed. 67% of patients had a cell differential performed. There was no difference in the ability to perform a synovial leukocyte count between samples process in < 2hours vs > 6 hours.

We conclude that it is safe practice to perform joint aspirates for the work up of periprosthetic joint infections in sites where no laboratory is immediately available as the delay to processing synovial fluid does not alter the ability to perform a synovial leukocyte count. This study will provide evidence to enable the work up of periprosthetic joint infections in cold centres and therefore reduce the delay in diagnosis and proceeding management.

Abstract

Prosthetic joint infections (PJI) are a devastating consequence in total hip arthroplasties (THA) with both significant morbidity and sometimes mortality, posing a significant health economic burden. Studies, both clinical and in-vitro have suggested possible reduction in PJI with the use of ceramic bearings.

We have investigated the relationship of ceramic-on-ceramic (CoC), ceramic-on-polyethylene (CoP) or metal-on-polyethylene (MoP) bearing surface in affecting outcome of revision surgery after primary THA using data collected from National Joint Registry for England and Wales, Northern Ireland and the Isle of Man between 2002 and 2016. We used a competing risk regression model to investigate predictors of each revision outcome, such as infection, dislocation, aseptic revision and all cause revisions. The results were adjusted for age, gender, ASA grade, BMI, indication for surgery, intraoperative complications and implant data.

We identified 456,457 THA (228,786 MoP, 128,403 CoC and 99,268 CoP). In a multivariable model, the adjusted risk of revision for PJI was lower with CoC (OR-0.748, p<0.001) and CoP (OR-0.775, p<0.001) when compared to MoP bearing. Additionally there was also a significant reduction in the risk of all cause revision for CoC (OR-0.918, p=0.002) and CoP (0.806, p<0.001), bearings as compared with MoP. The protective effect of ceramic bearing was predominantly seen after two years of implantation with a significant (p<0.0001) reduction of revision for PJI in both CoC (by 42.8%) and CoP (by 41.3%) group. Similarly significant effect was seen for aseptic revision beyond two years and overall all cause revision rate beyond two years reduced by 21.6% for CoC and 27.1% for CoP (p<0.001).

Within the limits of registry analysis, this study has demonstrated an association between the use of ceramic bearing and lower rates of revision for all cause revisions especially infection and aseptic loosening. This finding supports the use of ceramic bearings in THA.

Background

There is significant variation and inconsistencies in the current advice and information delivered to patients undergoing total hip replacement (THR). The aim of this study was to assess a locally developed web-based electronic resource system for patients undergoing total hip replacement (THR) surgery to see if this improves and standardises the content, structure, and delivery of information delivered to patients prior to and after surgery.

Introduction

Periprosthetic joint infection (PJI) can be difficult to diagnose. A variety of techniques have been described. The efficacy of the alpha-defensin laboratory test was examined and compared with other established modalities in the diagnostic workup of ‘real world’ arthroplasty patients.

INTRODUCTION

Dislocation is a major complication post total hip replacement (THR) and a common cause for revision. Jameson et al (2012) studied 35,000 cemented Exeter (Stryker) THRs demonstrating the risk of revision was significantly influenced by the acetabular component design. This led 3 surgeons in a single hospital group to make a mass move from using the hooded Exeter Low Profile (LP) cup to the better performing Contemporary Flanged (CF) component. The purpose of this study was to show whether this change was associated with a fall in dislocation rates.

Introduction

Revision of well cemented femoral components in revision THA can be technically challenging and time consuming. The cement in cement (CiC) technique addresses these issues. Results of femoral components which have undergone multiple CiC revisions have not previously been reported.

Introduction

National Institute for Health and Clinical Excellence (NICE) guidelines recommend the use of total hip replacement (THR) for displaced intracapsular fractured neck of femur (NOF) in cognitively intact patients who were independently mobile prior to the injury. The National Joint Registry for England and Wales (NJR) has collected data on THRs performed since 2003. This retrospective cohort study explores risk factors independently associated with implant failure and perioperative mortality.

Background

Current analysis of unicondylar knee replacements (UKR) by national registries is based on the pooled results of medial and lateral implants. Using data from the National Joint Registry for England and Wales (NJR) we aimed to determine the proportion of lateral UKR implanted, their survival and reason for failure in comparison to medial UKR.

Background

Both surgeon and hospital volume influence patient outcomes following revision knee arthroplasty.

Introduction

Following in-depth analysis of the market leading brand combinations in which we identified implant influences on risk of revision, we compared revision in patients implanted with different categories of hip replacement in order to find implant with the lowest revision risk, once known flawed options were removed.

Purpose

To determine how patient characteristics; health status and pre-operative knee function effect patient reported satisfaction and operative success following total knee replacement (TKR). We hypothesised that a number of patient factors would influence the reported levels of symptomatic improvement (success) and satisfaction and that these two outcomes would represent different aspects of the patient's perception of outcome.

Background

The most appropriate form of chemical thromboprophylaxis following knee replacement is a contentious issue. Most national guidelines recommend the use of low molecular weight Heparin (LMWH) whilst opposing the use of aspirin. We compared thromboembolic events, major haemorrhage and death after knee replacement in patients receiving either aspirin or LMWH.

Background

There is a lack of information on the independent preoperative predictors of perioperative mortality, including the influence of previous stroke and acute coronary syndromes (myocardial infarction + unstable angina, ACS). Previous studies have grouped variables under the umbrella term “ischaemic heart disease”. In this study, we investigated the influence of vascular risk factors separately.

Background

Dislocation is a major complication following total hip arthroplasty (THA). Aetiology is multi-factorial, but increasing femoral head size may result in lower dislocation rates. The latest England and Wales National Joint Registry (NJR) annual report has highlighted a statistically significant increase in the use of femoral heads of size 36mm+ from 5% in 2005 to 26% in 2009, together with an increase in the use of the posterior approach. The aim of this study was to determine whether national dislocation rates have fallen over the same period.

Background

Medical complications and death are rare events following elective orthopaedic surgery. Diagnostic and operative codes are routinely collected on every patient admitted to English NHS hospitals. This is the first study investigating rates of these events following total joint replacement (TJR) on a national scale.

Background

The National Institute for Health and Clinical Effectiveness recommends both low molecular weight heparin (LMWH) and Rivaroxaban for venous thromboembolic (VTE) prophylaxis following lower limb arthroplasty. Despite evidence in the literature that suggests Rivaroxaban reduces VTE events, there are emerging concerns from the orthopaedic community regarding an increase in wound complications following its use.

Background

In 2011 20% of intracapsular fractured neck of femurs were treated with an uncemented hemiarthroplasty in the English NHS. National guidelines recommend cemented implants, based on evidence of less pain, better mobility and lower costs. We aimed to compare complications following cemented and uncemented hemiarthroplasty using the national hospital episode statistics (HES) database in England.

Background

Medical complications and death are rare events following elective orthopaedic surgery. Diagnostic and operative codes are routinely collected on every patient admitted to hospital in the English NHS (hospital episode statistics, HES). This is the first study investigating rates of these events following total joint replacement (TJR) on a national scale in the NHS.

Background

A recent Cochrane review has shown that total shoulder arthroplasty (TSA) seems to offer an advantage in terms of shoulder function over hemiarthroplasty, with no other obvious clinical benefits. This is the first study to compare complication rates on a national scale.

Patient-reported outcome measures (PROMs) are increasingly being used to assess functional outcome and patient satisfaction. They provide a framework for comparisons between surgical units, and individual surgeons for benchmarking and financial remuneration. Better performance may bring the reward of more customers as patients and commissioners seek out high performers for their elective procedures. Using National Joint Registry (NJR) data linked to PROMs we identified 22 691 primary total knee replacements (TKRs) undertaken for osteoarthritis in England and Wales between August 2008 and February 2011, and identified the surgical factors that influenced the improvements in the Oxford knee score (OKS) and EuroQol-5D (EQ-5D) assessment using multiple regression analysis. After correction for patient factors the only surgical factors that influenced PROMs were implant brand and hospital type (both p < 0.001). However, the effects of surgical factors upon the PROMs were modest compared with patient factors. For both the OKS and the EQ-5D the most important factors influencing the improvement in PROMs were the corresponding pre-operative score and the patient’s general health status. Despite having only a small effect on PROMs, this study has shown that both implant brand and hospital type do influence reported subjective functional scores following TKR. In the current climate of financial austerity, proposed performance-based remuneration and wider patient choice, it would seem unwise to ignore these effects and the influence of a range of additional patient factors.

Introduction

Unlike the NJR, no surgeon driven national database currently exists for ligament surgery in the UK and therefore information on outcome and adverse event is limited to case series.

Introduction

The National Institute for Health and Clinical Effectiveness recommends both low molecular weight heparin (LMWH) and Rivaroxaban for venous thromboembolic (VTE) prophylaxis following lower limb arthroplasty. Despite evidence in the literature that suggests Rivaroxaban reduces VTE events, there are emerging concerns from the orthopaedic community regarding an increase in wound complications following its use.

Background

Following an anterior cruciate ligament (ACL) injury, the affected knee is known to experience bone loss and is at significant risk of becoming osteoporotic. Surgical reconstruction is performed to attempt to restore the function of the knee and theoretically restore this bone density loss. Cross-sectional analysis of the proximal tibia using peripheral quantitative computed tomography (pQCT) enables localised analysis of bone mineral density (BMD) changes. The aim of this study was to establish the pattern of bone density changes in the tibia pre- and post- ACL reconstruction using pQCT image analysis.

Bearing diameter and acetabular component orientation have been shown to be important variables effecting blood metal ion levels following hip resurfacing arthroplasty. So far no studies on bilateral hip resurfacings have taken into account these variables.

We examined the serum ion results of patients under the care of two experienced hip resurfacing surgeons who carry out ion analysis as part of routine post operative care. Surgeon 1: Patients were implanted exclusively with a “third generation” resurfacing device. Surgeon 2: Patients were implanted with the same “third generation” device and also a low clearance “fourth generation” resurfacing device. Only ion results from patients who were 12 months post surgery were included. Bilateral patients were matched to unilateral patients according to the surgeon performing the operation; the resurfacing system implanted and cup inclination and anteversion angles. The ion data from each bilateral group was tested against the corresponding unilateral groups using the Mann Whitney U test for non parametric data. Significance was drawn at p<0.05.

Surgeon 1: There were 310 patients with unilateral joints and 50 with bilateral joints. There were no significant differences with regard to time to follow up, activity levels, joint sizes or cup orientations. Serum chromium (Cr) and cobalt (Co) concentrations were significantly greater in the bilateral group (p<0.001). Median ion levels were greater in the bilateral group by a factor of >2 in the smallest joint sizes and <2 in the largest joints. Surgeon 2: There were 11 patients with bilateral third generation resurfacing joints and 50 with unilateral joints of the same design. The same relationship as described above was identified. There was a notable difference in the fourth generation implant group (n=13 bilateral, n=100 unilateral). Median ion levels for patients receiving bilateral joints of sizes <47mm were ten times greater than in the corresponding unilateral group.

Bearing diameter and component design are critical factors in determining metal ion levels following bilateral hip resurfacings. Surgeons must consider the potential implications of gross increases in metal ion levels prior to performing bilateral hip resurfacings in smaller patients.

Background

Total Knee Replacement (TKR) is technically demanding, time consuming and has higher complication rates in super obese (BMI>45) patients. Bariatric surgery can be considered for such patients prior to TKR although its effect on complications is unknown.

From August 2009, all doctors were subject to the European Working Time Directive (EWTD) restrictions of 48 hours of work per week. Changes to rota patterns have been introduced over the last two years to accommodate for these impending changes, sacrificing ‘normal working hours’ training opportunities for out-of-hours service provision. We have analysed the elogbook data to establish whether operative experience has been affected.

A survey of trainees (ST3-8) was performed in February 2009 to establish shift patterns in units around the UK. All operative data entered into the elogbook during 2008 at these units was analysed according to type of shift (24hr on call with normal work the following day, 24hr on call then off next working day, or shifts including nights).

66% of units relied on traditional 24hrs on call in February 2009. When compared with these units, trainees working shifts had 18% less operative experience (564 to 471 operations) over the six years of training, with a 51% reduction in elective experience (288 to 140 operations). In the mid years of training, between ST3-5, operative experience fell from 418 to 302 operations (25% reduction) when shifts were introduced.

This national data reflects the situation in UK hospitals in 2009, prior to the implementation of a maximum of 48 hours. It is expected that most hospitals will need to convert to shift-type working patterns to fall within the law. This could have significant implications for elective orthopaedic training in the UK.

Background: Diagnostic and operative codes are routinely collected on every patient admitted to National Health Service (NHS) hospitals in England and Wales (hospital episode statistics, HES). The data allows for linkage of post-operative complications and primary operative procedures, even when patients are re-admitted following a successful discharge. Morbidity and mortality data on foot and ankle surgery (F& A) has not previously been available in large numbers for NHS patients.

Methods: All HES data for a 44-month period prior to August 2008 was analysed and divided into four groups – hindfoot fusion, ankle fracture surgery, ankle replacement and a control group. The control group was of first metatarsal osteotomy, which is predominantly day case surgery where no above ankle cast is used. The incidence of pulmonary embolism (PE) and all cause mortality (MR) within 90 days, and a return to theatre (RTT, as a complication of the index procedure) within 30 days was calculated for each group.

Results: 7448 patients underwent a hindfoot fusion. PE, RTT and MR were 0.11%, 0.11% and 0.12% respectively. 58732 patients had operative fixation of an ankle fracture. PE, RTT and MR were 0.16%, 0.08% and 0.35%. 1695 patients had an ankle replacement. PE, RTT and MR were 0.06%, 0.35% and zero. 35206 patients underwent a first metatarsal osteotomy. PE, RTT and mortality rates were 0.02%, 0.01% and 0.03%.

Discussion: There is controversy regarding the use of venous thrombo-embolic (VTE) prophylaxis in foot and ankle surgery. Non-fatal PE in F& A surgery has previously been reported as 0.15%. NICE guidelines recommend low molecular weight heparin (LMWH) for all inpatient orthopaedic surgery. 94% of F& A surgeons prescribe LMWH to post operative elective inpatients in plaster according to a previous British Orthopaedic foot and ankle society survey. VTE events, RTT and mortality rates for all groups were extremely low, including inpatient procedures requiring prolonged immobilisation. We question the widespread use of LMWH.

Background: There is a paucity of published data with regard to the wear of failed metal on metal (MoM) resurfacing devices.

Materials and Methods: MoM components retrieved from patients from two independent centres experiencing failure secondary to ARMD were analysed using a Mitutoyo Legex 322 coordinate measuring machine (CMM) which has an accuracy of 0.8 microns. Between 4000 – 6000 points were taken on each explant, dependent on the size of the bearing surface. Maximum wear depths and total volumetric wear were calculated. These values were compared to those from control samples retrieved following uncomplicated fractures/femoral collapse secondary to avascular necrosis (after calculating equivalent yearly wear rates).

Results: 58 ARMD components were analysed. This included 22 36mm MoM THRs (DePuy Pinnacle), 28 DePuy ASRs and 8 Zimmer Duroms. There were 30 resurfacing fracture/avascular necrosis controls. Volumetric wear rates and maximum wear depths of ARMD resurfacing components were significantly greater than the resurfacing control group for both the ASR and Duroms (p< 0.05) however 2 ARMD components exhibited similar amounts of wear compared to controls. Wear rates of the ARMD THR group were significantly lower than the ARMD resurfacing group (p< 0.05).

Conclusions: Increased articular wear is associated with an increased incidence of local adverse effects including tissue necrosis, joint effusions and fractures. However, there are a minority of patients who can develop tissue necrosis in the absence of accelerated wear, implying a spectrum of sensitivity This is reflected in the incidence of ARMD in the patient groups at the main study centre: > 5% in the ASR group and approx 1% in the THR group. We believe this indicates a failure of adequate lubrication and the resultant negative effects in larger bearing devices.

Background: Definitive cup position for the reduction of blood metal ion levels has yet to be established.

Methods: Samples for serum metal ion analysis are taken routinely from patients under the care of the two senior authors of this paper. Both are high volume experienced hip resurfacing surgeons, one based in England, the other in Belgium. Metal ion results from two centres from patients with unilateral joints were correlated to size and orientation of femoral and acetabular components, UCLA activity score, age, time post surgery and post operative femoral head/neck ratios. EBRA software was used to assess cup inclination and anteversion on standing radiographs.

Cup orientation in vivo was compared to explant analysis of 60 retrieved resurfacing components using a coordinate measuring machine.

Results: Three resurfacing devices were studied. There were 620 results in total. Only femoral size and cup inclination/anteversion were found to have any effect on ion levels. In all devices, metal ion levels were inversely related to femoral size (p< 0.05). The device providing the smallest acetabular coverage arc was associated with the highest metal ion levels. Consistent throughout the implants, lowest ion levels were associated with cups with radiological inclination of 40–50° and anteversion 10–20°. Cup inclination angles lower than 40° were associated with posterior edge loading and likely sub-luxation of the femoral component.

Conclusion: The greater the coverage angle provided by the acetabular component, the greater the tolerance to suboptimal position. Lowest ion levels were found in well positioned lower clearance devices. Cup inclination/ante-version angles of 45/15+/−5° were associated with low ion levels in all three devices. We do not recommend cups to be placed with inclination angles below 40°.

Background: Blood metal ion levels have been shown to correlate with wear of retrieved components. Increased articular wear is associated with early failure. It is not clear what the management of patients with raised metal ions who remain asymptomatic should be.

Methods: A prospective study of the DePuy ASR resurfacing device was commenced in 2004 at our independent centre. Blood and serum metal ion analysis is carried out routinely. We assessed the clinical outcome of all patients with cobalt (Co) concentrations > 5μg/L (n=25). We consider this value to be a clear indicator of a poorly performing bearing surface. Patients who remained asymptomatic were brought back for repeat ions testing and clinical assessment. A parallel study was carried out to examine the relationship between the wear depth of retrieved explants (assessed using a coordinate measuring) and blood ion levels

Results: Increases in chromium(Cr) and Co levels from the second blood sample correlated with the first sample (p< 0.05). The four patients with the highest Cr Co levels went on to suffer spontaneous femoral neck fractures between 3 and 4 years post op (pseudotumours in two of these cases). Of the remaining 25, 5 were revised for worsening pain (large effusions and areas of tissue necrosis were seen at revision) and 10 were under investigation for new onset of pain. Wear depths correlated well with blood ion concentrations (p< 0.05) substantiating the results of another centre.

Conclusion: 60% of patients with raised metal ion levels went on to develop complications within two years of the blood test. This suggests patients may only have temporary tolerances to excessive concentrations of metal wear debris. One novel association appears to be spontaneous delayed femoral fracture. Results suggest increased ion concentrations associated with small joint size/sub optimal cup orientation will continue to rise and these patients should be followed up closely.

In our independent centre, from 2002 to 2009, 155 BHRs (mean F/U 60 months) have been implanted as well as 420 ASR resurfacings and 75 THRs using ASR XL heads on SROM stems (mean F/U 35)

During this period we have experienced a number of failures with patients complaining of worsening groin pain at varying lengths of time post operatively. Aspiration of the hip joints yielded a large sterile effusion on each occasion. At revision, there were copious amounts of green grey fluid with varying degrees of necrosis. There were 17 failures of this nature in patients with ASR implants (12 females) and 0 in the BHR group. This amounts to a failure of 3.5% in the ASR group.

Tissue specimens from revision surgery showed varying degrees of “ALVAL” as well as consistently high numbers of histiocytes. Particulate metal debris was also a common finding.

The mean femoral size and acetabular anteversion and inclination angles of the ARMeD group/all asymptomatic patients was 45/49mm (p< 0.001), 27/20°(p< 0.001) and 53/48°(p< 0.08). Median blood chromium(Cr) and cobalt(Co) was 29 and 69 μg/L respectively in the ARMeD group versus 3.9 and 2.7 μg/L in the asymptomatic patients (n=160 with ion levels). Explant analysis confirmed greater rates of wear than expected.

Lymphocyte proliferation studies involving ARMeD patients showed no hyper reactivity to Cr and Co in vitro implying that these adverse clinical developments are mediated by a toxic reaction or a localised immune response.

Our overall results suggest that the reduced arc of cover of the fourth generation ASR cup has led to an increased failure rate secondary to the increased generation of metal debris. This failure rate is 7% in ASR devices with femoral components _47mm.

Introduction: In August 2007, the Department of Health initiative Modernising Medical Careers was implemented. This was a system of reform and development in postgraduate medical education and training. In preparation for the changes, the SAC for T& O outlined a new curriculum. The emphasis of early training, StR years 1 and 2, was to be trauma. We aim to identify how effectively the SAC proposals are being applied, and what difference this makes to the trainees’ operative experience? Furthermore, how do the new posts compare to the historic SHO models?

Methods: A survey carried out by BOTA allowed us to assess post compliance with the SAC recommendations. A compliant job was defined as trauma based for 50% or more of working time. Consent was obtained to evaluate the eLogbooks of trainees in compliant and non-compliant jobs, along with registrars who had previously held traditional SHO grade posts. Overall operative experience over a specified 4 month time period was examined, with focus on routine trauma procedures.

Results: The results of the BOTA and SAC survey revealed that 45% of the new orthopaedic posts were compliant with curriculum guidelines. The eLogbooks of 92 individuals were analysed; 28 historical posts, 34 compliant and 30 non-compliant. The mean total number of recorded entries by trainees in the 4 month period was 73.2 in the historic group, 90.5 in the compliant and 87.3 in the non-compliant job group. The corresponding numbers of trauma operations were 35.7, 48.4 and 41.5.

Conclusions: Operative experience has improved since the introduction of the new curriculum. The new posts are offering more operative and in particular trauma exposure than traditional SHO jobs. If jobs can be restructured such that they all comply with the SAC, educational opportunities in the early years will be maximised.

Background: From August 2009, all doctors were subject to the European Working Time Directive (EWTD) restrictions of 48 hours of work per week. Changes to rota patterns have been introduced over the last two years to accommodate for these impending changes, sacrificing ‘normal working hours’ training opportunities for out-of-hours service provision. We have analysed the elogbook data to establish whether operative experience has been affected.

Methods: A survey of trainees (ST3-8) was performed in February 2009 to establish shift patterns in units around the UK. All operative data entered into the elogbook during 2008 at these units was analysed according to type of shift (24hr on call with normal work the following day [traditional on call], 24hr on call then off next working day, or shifts including nights).

Results: 66% of units relied on traditional 24hrs on call in February 2009. When compared with these units, trainees working shifts had 18% less operative experience (564 to 471 operations) over the six years of training, with a 51% reduction in elective experience (288 to 140 operations). In the mid years of training, between ST3-5, operative experience fell from 418 to 302 operations (25% reduction) when shifts were introduced.

Discussion: The eLogbook is a powerful resource that provides accurate data for the purpose of supporting orthopaedic training. This national data reflects the situation in UK hospitals in 2009, prior to the implementation of a maximum of 48 hours. It is expected that most hospitals will need to convert to shift-type working patterns to fall within the law. This could have significant implications for elective orthopaedic training in the UK.

Background: Diagnostic and operative codes are routinely collected on every patient admitted to hospital in England and Wales (hospital episode statistics, HES). Linked data allows post-operative complications to be associated with the primary operative procedure, even if patients are re-admitted following a successful discharge. Morbidity and mortality data on shoulder surgery have not previously been available in large numbers.

Methods: All HES data for a 42-month was analysed and divided into three groups – elective shoulder replacement (total or hemiarthroplasty), shoulder arthroscopy (all procedures), and proximal humerus fracture surgery (internal fixation or replacement). Incidence of pulmonary embolism (PE), deep venous thrombosis (DVT) and mortality within 90 days was established.

Results: For elective shoulder replacement (10735 patients), 90-day DVT, PE and mortality rates were 0.07%, 0.11% and 0.36% respectively. Mortality in patients over 75 years was 0.9%. For arthroscopic procedures (66344 patients), 90-day DVT, PE and mortality rates were 0.01%, 0.01% and 0.03%. For proximal humerus fracture surgery (internal fixation or replacement, 4968 patients) 90-day DVT, PE and mortality rates were 0.20%, 0.38% and 2.98%. Mortality in patients over 75 years old was 6.6%.

Discussion: Venous thromboembolic (VTE) prophylaxis is rarely used for upper limb surgery. PE and mortality rates for shoulder replacement and proximal humerus fracture surgery are lower those for patients receiving chemical prophylaxis after hip replacement. Further investigation into the cause of high mortality rates following fracture surgery in patients over 75 years old is required. VTE prophylaxis may be required in this age group.

Since 2003 Trauma and Orthopaedic trainees in the UK and Ireland have routinely submitted data recording their operative experience electronically via the eLog-book. This provides evidence of operative experience of individuals and national comparisons of trainee, trainer, hospital and training programme performance. We have analysed trauma surgery data and established standards for training.

By January 2008 there were over 4 million operations logged. Operations performed and uploaded since 2003 have been included. Each trainee’s work is analysed by ‘year-in-training’. Data on levels of supervision, missed opportunities (where the trainee assisted rather than performed the operation) was analysed. The average number of trauma operations performed annually by trainees was 109, 120, 110, 122, 98 and 84 (total 643) for YIT one (=ST3) to six (=ST8) respectively. There were only 22% of missed opportunities throughout six years of training. A high level of experience is gained in hip fracture surgery (121 operations) and forearm (30), wrist (74) and ankle (47) operative stabilisation over the six years. However, the average number of tibial intra-medullary nails (13), external fixator applications (12) and childrens’ elbow supracondylar fracture procedures (4) performed is low. We are also able to identify trainees performing fewer operations than required during their training (two standard deviations or more below the mean for their YIT). We expect a trainee to have performed at least 255, 383, 473, and 531 trauma operations at the end of YIT three to six respectively.

The eLogbook is a powerful tool which can provide accurate information to support in-depth analysis of trainees, trainers, and training programmes. This analysis has established a baseline which can be used to identify trainees who are falling below the required operative experience.

Tarsal fractures are rare in children. Clinical and radiographic evaluation of these injuries can be difficult. We present a retrospective study documenting all tarsal fractures presenting to an inner-city children’s hospital in the UK over a fifteen year period.

Of 70 case notes retrieved from the hospital database, 7 patients were excluded due to inadequate data. This resulted in 69 tarsal injuries in 63 patients being included. Mean age at presentation was 9.3 years (2.5 – 13.9). 80% were male. 72% were calcaneal fractures, 12% cuboid, 9% navicular, 4% talus and 2% medial cuneiform. The main method of diagnosis was plain x-rays. Cause of injury was predominantly fall from height, crush or road traffic accident. 25% had another associated lower extremity injury. Three patients had bilateral tarsal injuries. Only 3% had upper limb injuries and there were no injuries with spinal involvement. Calcaneal fractures were treated with a short leg cast for a mean time of 4.1 weeks (2–6). Mean time to recovery was 5.7 weeks (2–20). Mean time to discharge from clinic was 7 weeks (2–40). There were two patients with open fractures requiring surgical debridement. One patient with a talar fracture had percutaneous fixation. Only one patient re-presented with pain following discharge. X-rays showed healing avascular necrosis of the proximal talus.

Tarsal fractures are rare, usually benign and most require simple immobilisation for only a short period of time. Surgical intervention is only occasionally required in complex injuries. Complications and long term problems are rare, even following open injuries.

This report documents the clinical and histological findings, the operative management and the explant analyses of patients with early aseptic failure of large metal-on-metal (MonM) bearing joints.

Three hundred and fifty patients have been implanted with the ASR bearing surface (resurfacing or a modular THR) by a single surgeon at an independent centre since 2004. Six patients (all female) have been revised secondary to aseptic failure. All complained of severe groin pain exacerbated by straight leg raise and routine investigations were unable to establish a cause. Large amounts of sterile, highly viscous green fluid were aspirated from the hip joints in each case. Gross swelling of the pseudocapsule and a similar green fluid surrounding the implants were found at revision surgery. Histological examination of periprosthetic tissue samples showed changes consistent with ALVAL/metallosis, and analysis of the fluid revealed dense numbers of inflammatory cells. Symptoms in patients revised to ceramic-on-ceramic bearings improved post operatively. This was not the case with those reimplanted with MoM joints. Data from a subset of 76 patients (all unilateral resurfacings) showed that malaligned cups (anteverted > 20° +/− inclination angle > 45°) were associated with significantly higher whole blood metal ion levels than cups positioned within this range. All the patients with early aseptic failure had malaligned cups. Independent explant analysis revealed significant increases in the surface roughness values of the articular surfaces.

Our results suggest that some patients develop a significant inflammatory reaction to metal implants. This may be due to high levels of metal debris around the implant as a result of accelerated wear. Poor component alignment was found in all our patients with early aseptic failure.

The first United Kingdom In-training Examination (UKITE) was held in 19 training programmes during December 2007. The aims of the project are to offer a national, online examination (providing immediate results to trainees) and to allow practice for the ‘real’ FRCS T& O examination with similarly formatted questions based on the UK T& O curriculum. All Speciality training years (StR2, StR3 and above, and all SpRs) and all deaneries will participate in the future. A total of 450 trainees sat this first examination. This is an online exam (accessed through the eLogbook/OCAP website) which is voluntary and has no bearing on RITA outcomes. To take part in the exam trainees were asked to provide 3 questions for a bank which can be used in subsequent years for both UKITE and the FRCS T& O examination.

The exam was 3 hours and questions were of multi-choice (MCQ) and extended matching question (EMQ) style covering all aspects of orthopaedics. Correct answers and explanations were available to the trainee after their answer had been submitted. Final scores ranged from 35% to 92%. Mean scores increased from 48% (StR2) to 73% in SpR year 5 (StR7 equivalent). This was followed by a drop off in performance in the final year of training. Three candidates had equal top scores at 92%. 97% stated they would sit the UKITE again and 93% felt there was educational benefit. The length and level of difficulty of the exam was felt to be satisfactory. Improvements were suggested for question quality. The UKITE is a powerful tool for self-assessment of trainees. This analysis establishes a baseline for future years.

Metal ion concentrations following metal on metal hip resurfacing arthroplasty remain a concern. Variables associated with increased metal ion concentrations need to be established. This study provides metal ion data from a consecutive cohort of the first 76 patients implanted with a fourth generation hip resurfacing prosthesis.

All patients agreed to post-operative blood metal ion sampling at a minimum of one year. Post-operative radiographic measurements of cup inclination and anteversion were obtained using the EBRA software. Mean whole blood chromium (Cr) and cobalt (Co) concentrations in patients receiving the smallest femoral implants (Ł51mm) were greater than in the patients implanted with the largest prostheses (ł53mm) by a factor of 3 and 9 respectively. Ion concentrations in the small femoral group were significantly related to acetabular inclination (R=0.439, P< 0.001 for Cr, R=0.372, P=0.004 for Co) and anteversion (R=0.330, P=0.010 for Cr, R=0.338, P=0.008 for Co). This relationship was not significant in the large implant group. Mean Cr and Co concentrations in patients with accurately orientated cups (inclination < 45°, anteversion < 20°) were 3.7μg/l and 1.8 μg/l respectively, compared to 9.1μg/l and 17.5μg/l in malaligned cups.

A reduced surface contact area caused by cup malalignment may increase contact stresses, resulting in a high wear rate if fluid film lubrication is inadequate. Improved fluid film lubrication has previously been found in larger heads in vitro. Accurate acetabular component positioning is essential in order to reduce metal ion concentrations following hip resurfacing.

National Institute for Clinical Excellence (NICE) guidelines on venous thromboembolic (VTE) prophylaxis for patients undergoing orthopaedic surgery recommend that all inpatients be offered a low molecular weight heparin (LMWH).

Linked hospital episode statistics of 219602 patients were examined to determine the rates of complications following lower limb arthroplasty for the 12-month periods prior to and following the publication of these guidelines. This was compared with data from the National Joint Register (England and Wales) regarding LMWH usage during the same periods.

There was a significant increase in the reported use of LMWH (59.5 to 67.6%, p< 0.01) between the two periods. However, 90-day VTE events increased following both total hip (THR, 1.67% to 1.84%, p=0.06) and knee replacement (TKR, 1.99% to 2.04%, p=0.60). 30-day return to theatre rate for infection fell following TKR, but increased after THR. In addition, there were increases in rates of thrombocytopenia, which was significant following THR (p=0.03).

Recommendations from NICE are based on predicted reductions in VTE events, reducing morbidity, mortality and costs to the National Health Service. Early results in orthopaedic patients are unable to support these predictions.

Background: Calcaneal osteotomy is performed commonly as an adjunct to many corrective procedures of the abnormal hindfoot. Preservation of the hindfoot joints restores the normal biomechanics and can potentially delay arthritic changes in adjacent joints. Calcaneal osteotomy improves the weight bearing alignment of the foot by reducing varus or valgus deformity without impairing subtalar or mid-tarsal joint function. We are unaware of any studies documenting the complication rates associated with this procedure.

Methods: 36 calcaneal osteotomies (medial and lateral displacement, and Dwyer) were performed on 35 patients between April 2005 and October 2007 by the senior surgeon. Data was collected retrospectively by review of casenotes and assessment of radiographs. Average age was 54 years (range 18 to 81) and mean time of follow-up was 22 months (6 to 36). Indications were varus OA deformity (40%), Posterior tibialis tendon deficiency (30%), Charcot-Marie-Tooth (12%) and pes cavus (17%).

Results: All case notes and radiographs were available for analysis. Eight patients (22%) developed a complication. One patients (5%) had failed to fuse at 6 weeks following surgery. This patients developed a non-union and required re-fusion with bone grafting. Two patients (10%) had sural nerve damage, which persisted and required specialist pain team involvement. Two patients developed symptoms relating to prominent screws. A further two patients had wound breakdown and one had a superficial infection. In total, there were five further procedures (14%) – two directly related to problems with the calcaneal osteotomy. All osteotomies united within a translation distance of 10% in the sagittal plane.

Discussion: Calcaneal osteotomy is a useful adjunct procedure for correcting anatomical malalignment of the hindfoot in several conditions, with an acceptable complication rate and a low re-operation rate.

Background: There are no large comparative metal ion studies of commercially available hip resurfacing devices which have taken into account the effects of femoral size and cup inclination and anteversion.

Patients and methods: Metal ion analysis is carried out routinely at our independent centre. We present the metal ion results of 95 unilateral ASR patients and 70 unilateral BHR patients. For all patients, acetabular cup orientation was assessed using EBRA software. Patients with other metallic implants and those within 12 months of surgery were excluded.

Results: Whole blood/serum chromium (Cr) and cobalt (Co) concentrations were inversely related to femoral component size in both the ASR and BHR group (p< 0.05). Cr and Co levels were only seen to increase in the BHR group when the cup was implanted with an inclination greater than 55°. A significant relationship was identifed between the anteversion of the BHR cup and Cr and Co (p< 0.05 for Co, Spearman Rank correlation), with an increase in ions observed at anteversion angles > 17°. Cr and Co were more strongly influenced by cup position in the case of the ASR, with an increase in metal ions observed at inclinations greater than 45° and anteversion angles of < 10° and > 20°.

Discussion: The increased tolerance of the BHR cup to inclinations between 45–55° is likely due to the larger BHR cup providing greater protection against edge loading. When the cohort was divided by gender, the median Cr concentrations of the male ASR patients were significantly lower than those of the BHR males (p< 0.001). This suggests that in larger components positioned at more satisfactory angles of inclination and anteversion, the lower clearance of the ASR proves more significant than the extra coverage provided by the BHR cup. The BHR appears to be more sensitive to changes in anteversion than inclination.

Background: There is a paucity of published literature with regard to metal ion levels following bilateral hip resurfacings.

Method: Recent research has identified femoral component size and acetabular cup anteversion and inclination as important variables involved in metal ion release into the blood. We compared 13 patients with bilateral joints resurfaced using the ASR and 11 patients with bilateral BHRs to those with unilateral joints of similar size and cup inclinations/anteversions. Patients were excluded if the last procedure was within 12 months of blood sampling and if they had other metallic implants. Analysis of standing radiographs to determine cup orientation was carried out using EBRA software. Blood samples were analysed using ICPMS.

Results: Median whole blood Cr and Co values were higher in the BHR bilateral group when compared to the unilateral BHR group by a factor of 1.12 and 1.24 respectively. (5.17 vs 4.59 for Cr, 2.40 vs 1.93 for Co). The difference was significant for Co (p=0.030) but not for Cr (p=0.136). For the large ASR joints (53mm), median Cr and Co values were higher in the bilateral group by a factor of 1.5 and 1.85 respectively. (4.55 vs 2.97 (Cr) 2.83 vs 1.53 (Co)). The difference was significant for both Cr (p=0.001) and Co (p=0.022). For the small ASR joints (< 53mm), median Cr Co values were higher in the bilateral group by a factor of 1.95 and 2.30 respectively. (8.29 vs 4.25 (Cr), 6.78 vs 2.94 (Co)) (p=0.019 Co) (p=0.007 Co).

Conclusion: Metal ion concentrations are significantly greater in patients with bilateral resurfacings. The Cr Co concentrations observed in our patients with bilateral small ASR joints are double those in the published literature on bilateral 28mm metal on metal(MoM) joints implying that the lubrication achieved by small ASRs is sub optimal.

Introduction: Excellent medium term results have been reported with the BHR hip resurfacing implant. A number of modifications have been made to the latest designs in an attempt to preserve acetabular bone stock, improve function and prolong survival. We present the clinical and radiological results from the first independent series of ASR resurfacings.

Methods: The first consecutive series of 214 ASR hip resurfacings (192 patients) were followed up prospectively. No patients were lost to follow-up. The mean age of patients at implantation was 56 years and 40% were female. All patients had pre- and 2-year post-operative Harris Hip Scores (HHS) and UCLA activity scores. Radiographic and implant survival analysis was performed at 24–54 months following implantation.

Results: One hundred and seventy-three hips (87%) had an excellent Harris Hip Score (90 or above). Mean postoperative UCLA activity score was 7 and 92% were highly satisfied with the outcome. There were eleven revisions (5.1%). Four (1.9%) had femoral neck fractures (three had a femoral neck notch), two (0.9%) collapsed secondary to avascular necrosis and five (2.3%) were revised because of ongoing pain, as a result of metal wear debris.

Discussion: Although the fracture rate is similar to reports in the literature, the overall revision rate was higher. Rates of wear debris-related failure is concerning. Further investigation of specific implant failure is necessary.

In our independent centre, in the period from January 2003 to august 2008, over 1100 36mm MoM THRs have been implanted as well as 155 Birmingham Hip Resurfacing procedures, 402 ASR resurfacings and 75 THRs using ASR XL heads on SROM stems.

During this period we have experienced a number of failures with patients complaining of worsening groin pain at varying lengths of time post operatively. Aspiration of the hip joints yielded a large sterile effusion on each occasion. At revision, there were copious amounts of green grey fluid with varying degrees of necrosis. There were 11 failures of this nature in patients with ASR implants (10 females) and 2 in the 36 MoM THR group (one male one female).

Tissue specimens from revision surgery showed varying degrees of ‘ALVAL’ as well as consistently high numbers of histiocytes. Metal debris was also a common finding.

A fuller examination of our ASR cohort as a whole has shown that smaller components placed with inclinations > 45° and anteversions < 10 or > 20° are associated with increased metal ion levels. The 11 ASR failed joints were all sub optimally positioned (by the above definition), small components.

Explant analysis using a coordinate measuring machine and out of roundness device confirmed greater than expected wear of each component. The lower number of failures in the 36mm MoM group, as well as the equal sex incidence, suggests that the majority of these failures are due to the instigation of an immune reaction by large amounts of wear debris rather than adverse reactions to well functioning joints. It is likely that small malpositioned ASRs function in mixed to boundary lubrication, and this, combined with the larger radius of these joints compared to the 36mm MoM joints, results in more rapid wear.

Introduction: There are ongoing concerns regarding metal wear debris following the use of metal-on-metal (MonM) bearings for hip surface and total arthroplasty. A Type IV Hypersensitivity reaction to MonM articulations has previously been identified (aseptic lymphocyte dominated vasculitis associated lesion, ALVAL) but little is known of its incidence, diagnosis or management. Persisting groin pain in MonM patients may be undiagnosed ALVAL. At our single centre we have reviewed and compared three types of MonM articulations to examine the incidence of ALVAL and to identify trends.

Methods: The resurfacing group comprised 250 patients with the ASR prosthesis. In the resurfacing hybrid total hip replacement (THR) group there were 86 patients implanted with an ASR head on a stem. The final group comprised of 625 patients with a MonM THR using a 36mm Pinnacle head. Both the S-ROM and the Corail stems were used in the THR groups. Patients with persisting and activity-restricting groin pain had tests for infection. Patients were counselled and revision was offered if ALVAL was suspected from the clinical picture, blood results and the aspiration result. Specimens for microbiological and histological analysis were taken at the time of revision.

Results: We found 5 cases of histologically proven ALVAL in the absence of infection in 961 patients. The incidence was: 1.2% in the resurfacing group, 2.3% of Resurfacing Hybrid THR group and 0 in the 36 mm THR group. All 5 cases were in female patients. Only 1 case had any radiological abnormality. One patient was initially revised from a resurfacing to a 36mm MonM THR without clinical success. All patients have now been revised to ceramic-on-ceramic bearings with improvements in outcome.

Discussion: ALVAL may be under-diagnosed. The 5 patients we describe showed good clinical recovery following their primary procedure. However, activity levels decreased and pain increased at 6–12 months post-op. All described non-specific systemic symptoms. On examination, a painful straight leg raise was a characteristic finding. This may result from the significant effusion found around the hip at each revision. Fluid aspirated from these hips was of a characteristic colour (green grey) and viscosity. The failure of the revision of a resurfacing to a smaller MonM bearing highlights the problem of sensitisation to the metal debris. Any subsequent revision to a MonM bearing is unlikely to improve clinical outcome. This finding is consistent with previous reports in the literature. Our results suggest the incidence of ALVAL may be higher that previously thought. We suggest all patients with significant groin pain should have inflammatory markers tests and a hip aspiration performed. In the absence of infection, revision to an alternative bearing surface may be indicated.

Introduction: Potential problems resulting from metal-on-metal hip wear debris are well known. Previous studies have shown an association between high cup angles and raised metal ion levels, but a link to clinical outcome has yet to be established. We aim to show the relationship between high cup angles, raised metal ion levels and pain following hip resurfacing.

Methods: This analysis comprised the first 250 Depuy ASR hip resurfacings performed by a single surgeon (senior author) over a 3 yr period at an independent centre. Patients were followed up, examined and x-rayed at regular intervals. We measured Harris Hip Score (HHS) and pain. The acetabular cup inclination angles were measured from standardised pelvic radiographs. A subgroup of 80 patients had serum and whole blood chromium and cobalt measurements performed. This subgroup comprised patients with a similar sex split, age, activity level, follow-up and cup angle profile to the parent group.

Results: HHS improved from 51.6 pre-operatively to 94.6 post-operatively. Males had a significantly higher post-op HHS (97.1) compared with the females (91.0). 2.1% of male patients had pain compared with 8.7% of females. High cup angles were associated with pain in females. This relationship did not occur in males. In patients with cup angles of 48° and above there were no males with pain compared to 15.4% of females. Females under 48° had a HHS of 93.7 compared to 88.0 for those over 48°. When we analysed metal ion levels there was a similar relationship. Patients with cup angles of 48° and above had significantly higher serum and whole blood chromium and cobalt levels compared with lower cup angles. Three patients with cup angles over 50° developed ALVAL (aseptic lymphocyte dominated vasculitis associated lesion) based on histological findings. All were female.

Discussion: High cup angles are associated with increased pain and elevated metal ion levels. Women seem to be more intolerant of an higher cup angle than men. This may be a consequence of the smaller prostheses in females. Cups implanted lower than 48° had a better clinical outcome and less metal ion wear. Like other 4th generation designs, the ASR cup is not a complete hemisphere (unlike the BHR) and may be susceptible to edge loading at lower inclination angles than previously thought. We believe the current recommendation of 45° +/−5° is too high based on our findings. We recommend an inclination angle that does not exceed 48°.

Optimal cup orientation for metal-on-metal hip resurfacing has yet to be established. Guidance is based on hip replacement data and in vitro studies. We sought to determine the influence of component size and positioning on early clinical outcome.

This study comprises a consecutive series of 200 hip resurfacings. All had Harris Hip Scores (HHS) at one-year review. Acetabular inclination angles were measured on pre-operative radiographs, and cup inclination/anteversion angles on 3-month post-operative films using EBRA. Restoration of anatomy was defined as placement of the cup within +/−5 degrees of pre-operative inclination. The difference between pre-operative acetabular and post-operative cup inclination was termed cup-angle difference (CAD).

HHS inversely correlated with CAD (P=0.023) and anteversion (P=0.003), and directly correlated with femoral head size (P< 0.001). In patients with restoration of inclination anatomy mean HHS at one year was significantly higher at 98.7 compared with cups placed outside the normal anatomy restoration limits (93.8, P=0.003). Patients with anteversion > 20 degrees had a significantly lower HHS (P=0.010) compared with cups anteverted < 20 degrees. 96% of patients with HHS < 90 had malaligned cups (inclination over 45 degrees, anteversion over 20 degrees).

Restoring pre-operative cup inclination, anteverting the cup < 20 degrees and using large femoral heads improves early clinical outcome following MonM hip resurfacing. We recommend accurate pre-operative planning and meticulous attention to intra-operative cup positioning with these results in mind.

Resurfacing metal-on-metal hip arthroplasty is currently showing promising clinical results. However there are concerns related to such implants, including the elevated levels of metal ions typically seen in patients. Valuable data can be obtained from explanted prostheses but due to their recent introduction few retrieval studies on resurfacing hip prostheses have been published.

Five ASR hip resurfacing prostheses were revised due to pain. From two patients, head and cup were available for independent explant analysis. In the other three cases only femoral components were available. All were removed from female patients and all were revised to ceramic-on-ceramic hip prostheses. Post-operative radiographic measurements of cup inclination and ante-version were obtained using the EBRA software. The surface roughness values of the articulating surfaces of the explants were measured using a non-contacting profilometer. A co-ordinate measuring machine was used to measure the diameter of the head and the cup and thus the diametral clearance. The same measurements were then taken from a new unused ASR prosthesis and compared. Using elastohydrodynamic theory the minimum effective film thickness of the implant was calculated. In turn this allowed the lubrication regime to be determined.

The average roughness values of the head and the cup of one implant were found to be 0.135microns and 0.058microns respectively, with a diametral clearance of 110microns. These results indicated that, at the time of removal, the prosthesis would have operated in the boundary lubrication regime. Other explants showed evidence of localised contact between the head and the rim of the acetabular cup, and these showed articulating surfaces with typical roughness values of between 0.025microns and 0.050microns. The new ASR had head and cup surface roughness values of 0.010microns and 0.012microns respectively and a diametral clearance of 87microns, implying that a new implant would operate under fluid film lubrication. All cups five were implanted with inclination angles over 45 degrees and anteversion over 25 degrees.

These results suggest that components with high inclination and anteversion angles display greater than expected wear and may operate in boundary rather than fluid film lubrication which may eventually lead to early failure.

Introduction: Patient selection has been critical to the excellent medium-term clinical results following hip resurfacing. Hypersensivity to metal ion debris has been described in previous generations of metal-on-metal bearings. This may also be a problem that affects modern designs. Characteristic histological changes have been identified (ALVAL). There are few studies that include large female numbers, and show separate outcome and implant survival.

Methods: Eighty-one female hips at a mean of 23 months (11–43) had an ASR hip resurfacing procedure at a single-surgeon independent centre. Mean age was 55 years (28–69). Harris Hip Scores (HHS) were recorded at one-year follow-up. Failures were analysed.

Results: HHS improved from 46.4 (11–77) to 90.2 (27–100). Overall, there was a 7.4 % revision rate. There were 3 femoral neck fractures. In the entire series of 98 female patients there were 3 cases of severe pain requiring revision (3.1%). All three patients had HHS < 50 at one year follow-up. Patients had groin pain, reduced flexion and a painful straight leg raise. Blood results were not suggestive of infection. Aspiration of the hip joint in each case revealed copious amounts of milky green grey aseptic fluid. All had similar macroscopic changes at revision. There were characteristic histological changes in keeping with ALVAL. All 3 patients were revised to THRs with ceramic bearings.

Discussion: The failure rate of 7.4% in the older female group is poor at this early stage following hip resurfacing. The incidence of metal hypersensitivity in our series suggests this complication may be more common than previously thought. Patients with persisting pain of unknown aetiology following resurfacing at other centres may have metal hypersensitivity.

Introduction: Hip resurfacing is a successful pain-relieving procedure which restores function in young patients. However, some patients have persisting pain. We suggest that load characteristics in relation to position of the cup may influence these symptoms. We aimed to determine the effect of acetabular cup inclination angle on pain following hip resurfacing.

Methods: 92 consecutive hips in 81 patients were resurfaced with the ASR prosthesis. The average age was 56.5 years (35–72). 33 were female hips. Harris Hip Scores (HHS) and UCLA activity scores were recorded pre-operatively and at last follow-up. Patient satisfaction was recorded. Acetabular cup inclination angle was measured. An acceptable angle for hip replacement is 45 degrees +/− 5 degrees. We therefore grouped cups into those above 50 degrees and those below. Average follow-up was 17.9 months (8–31). There were 39 hips with an angle less than 50 degrees (A), and 53 greater than 50 (B). Patients in each group were comparable for age, sex, follow-up and BMI.

Results: In group A HHS improved from 53.4 to 98.7 and UCLA activity score improved from 4.2 to 7.5. All patients were extremely or very pleased. In group B HHS improved from 49.0 to 94.0 and UCLA activity score improved from 3.9 to 7.1. 48 of 53 patients were extremely or very pleased. At follow up 37 of 39 (95%) of patients in group A had no pain. In group B 35 of 53 had no pain (66%). This is a statistically significant difference when analysed with Fisher’s exact test (p< 0.05).

Discussion: This study shows that an excessively open acetabular cup may contribute to persisting pain and patient dissatisfaction. This may be a result of excessive eccentric wear and metal ion deposition, and may lead to early failure of the prosthesis.

Introduction: Traditionally, hip resurfacing has been performed in younger patients. We compared the early results of a single surgeon series of ASR resurfacings performed in male patients in this age group with men over 60 years old.

Methods: 114 consecutive procedures were performed in male patients. Group 1 consisted of 48 hips in 43 patients aged 60 years and over (average age 64.2, range 60 to 73). Group 2 consisted of 66 hips in 59 male patients aged below 60 years (average age 50.4, range 31–59). Patients were followed up at a mean of 17.1 months in group 1 and 19.4 in group 2. BMI, ASA grade and proportion of Charnley walking grade A patients was similar.

Results: In group 1, average HHS improved from 56.4 to 98.6 and in group 2 from 54.2 to 96.7. Average UCLA activity score improved from 4.3 to 7.2 in group 1 and 4.1 to 7.7 in group 2. There has been 1 revision for neck fracture in group 1 (neck notched at time of primary procedure). There were no revisions in group 2. All of the patients in group 1, and 57 of 59 patients in group 2, give a high satisfaction rating. In group 1, one radiograph demonstrates lucency surrounding the ace-tabular component. This patient is asymptomatic with a HHS of 100 and a UCLA activity score of 10. There are areas of incomplete lucency around the components of a further 8 hips in group 1 and 10 in group 2. There has been no migration of components in either group.

Discussion: Functional outcome in patients over 60 years appears to be similar to younger patients. The early results are encouraging; we will continue to offer this procedure to active patients over 60. The areas of lucency on the radiographs will need careful follow-up to determine the long-term significance of these changes.

This paper considers the new financial infrastructure of the National Health Service and provides a resource for orthopaedic surgeons. We describe the importance of accurate documentation and data collection for National Health Service hospital Trust finances and league tables, and support our discussion with examples drawn from our local audit work.

Introduction Smaller skin incisions during a minimally invasive approach to total hip arthroplasty may accelerate rehabilitation and reduce inpatient stay. Cutaneous nerve injury from a standard 20cm lateral approach was compared with a new, oblique minimally invasive 10cm incision.

Method The two surgical approaches were defined on fifteen cadaveric thighs. Cutaneous nerves lying deep to the incisions were dissected out. Projected nerve injury resulting from each approach was recorded.

Results The mean number of nerves divided by a standard approach was 5.0 compared with 4.1 in the minimally invasive approach (mean difference 0.87, 95% confidence interval 0.03 to 1.7, P=0.043). However, the mean number of nerves per cm divided by the standard approach was 0.25 compared with 0.41 by the minimally invasive (mean difference −0.163, 95% confidence interval −0.09 to −0.24, P< 0.001).

Discussion The oblique incision ran perpendicular to the underlying cutaneous nerves; therefore, more cutaneous nerves were divided per cm than a standard approach. A 10cm oblique incision divides as many nerves as a 16cm standard approach.