There is a paucity of data available for the use of Total Femoral Arthroplasty (TFA) for joint reconstruction in the non-oncological setting. The aim of this study was to evaluate TFA outcomes with minimum 5-year follow-up.

This was a retrospective database study of TFAs performed at a UK tertiary referral revision arthroplasty unit. Inclusion criteria were patients undergoing TFA for non-oncological indications. We report demographics, indications for TFA, implant survivorship, clinical outcomes, and indications for re-operation.

A total of 39 TFAs were performed in 38 patients between 2015–2018 (median age 68 years, IQR 17, range 46–86), with 5.3 years’ (IQR 1.2, 4.1–18.8) follow-up; 3 patients had died. The most common indication (30/39, 77%) for TFA was periprosthetic joint infection (PJI) or fracture-related infection (FRI); and 23/39 (59%) had a prior periprosthetic fracture (PPF). TFA was performed with dual-mobility or constrained cups in 31/39 (79%) patients. Within the cohort, 12 TFAs (31%) required subsequent revision surgery: infection (7 TFAs, 18%) and instability (5 TFAs, 13%) were the most common indications. 90% of patients were ambulatory post-TFA; 2 patients required disarticulation due to recurrent PJI. While 31/39 (79%) were infection free at last follow-up, the remainder required long-term suppressive antibiotics.

This is the largest series of TFA for non-oncological indications. Though TFA has inherent risks of instability and infection, most patients are ambulant after surgery. Patients should be counselled on the risk of life-long antibiotics, or disarticulation when TFA fails.

Introduction

A proportion of patients with hip and knee prosthetic joint infection (PJI) undergo multiple revisions with the aim of eradicating infection and improving quality of life. The aim of this study was to describe the microbiology cultured from multiply revised hip and knee replacement procedures to guide antimicrobial therapy at the time of surgery.

Primary total hip replacement (THR) is a successful and common operation which orthopaedic trainees must demonstrate competence in prior to completion of training. This study aimed to determine the impact of operating surgeon grade and level of supervision on the incidence of 1-year patient mortality and all-cause revision following elective primary THR in a large UK training centre.

National Joint Registry (NJR) data for all elective primary THR performed in a single University Teaching Hospital from 2005–2020 were used, with analysis performed on the 15-year dataset divided into 5-year temporal periods (B1 2005–2010, B2 2010–2015, B3 2015–2020). Outcome measures were mortality and revision surgery at one year, in relation to lead surgeon grade, and level of supervision for trainee-led operations.

9999 eligible primary THR were undertaken, of which 5526 (55.3%) were consultant led (CL), and 4473 (44.7%) trainees led (TL). Of TL, 2404 (53.7%) were non-consultant supervised (TU), and 2069 (46.3%) consultant supervised (TS). The incidence of 1-year patient mortality was 2.05% (n=205), and all-cause revision was 1.11% (n=111). There was no difference in 1-year mortality between TL (n=82, 1.8%) and CL (n=123, 2.2%) operations (p=0.20, OR 0.78, CI 0.55–1.10). The incidence of 1-year revision was not different for TL (n=56, 1.3%) and CL (n=55, 1.0%) operations (p=0.15, OR 1.37, CI 0.89–2.09). Overall, there was no temporal change for either outcome measure between TL or CL operations. A significant increase in revision within 1-year was observed in B3 between TU (n=17, 2.7%) compared to CL (n=17, 1.0%) operations (p=0.005, OR 2.81, CI 1.35–5.87).

We found no difference in 1-year mortality or 1-year all-cause revision rate between trainee-led primary THR and consultant-led operations over the entire fifteen-year period. However, unsupervised trainee led THR in the most recent 5-year block (2015–2020) has a significantly increased risk of early revision, mainly due to instability and prosthetic joint infection. This suggests that modern surgical training is having a detrimental effect on THR patient outcomes. More research is needed to understand the reasons if this trend is to be reversed.

Aim

Patients with late acute periprosthetic joint infections (PJI) and treated with surgical debridement have a high failure rate. Previous studies have shown that rheumatoid arthritis (RA) is an independent risk factor for treatment failure. We conducted a case-control study to identify predictors for failure in late acute PJI treatment in RA patients. We hypothesize that patients with RA have a higher failure rate compared to controls due to the use of immunosuppressive drugs.

Abstract

Aims

The last decade has seen a marked increase in surgical rib fracture fixation (SRF). The evidence to support this comes largely from retrospective cohorts, and adjusting for the effect of other injuries sustained at the same time is challenging. This study aims to assess the impact of SRF after blunt chest trauma using national prospective registry data, while controlling for other comorbidities and injuries.

Introduction

The use of the Taylor Spatial Frame (TSF) in the management of tibial fractures and deformity correction is well established in the literature, however the majority of published papers are small in patient number. The aim of the project was to evaluate clinical and radiographic outcomes of patients with tibial fractures treated with a TSF.

Aim

This study assesses the ability of the JS-BACH classification of bone infection to predict clinical and patient-reported outcomes in prosthetic joint infection (PJI).

Treatment of periprosthetic joint infection (PJI) can include local delivery of antibiotics. A frequently used medium is absorbable calcium sulphate beads. The aims of this study were to:

identify how often organisms in infected THRs are sensitive to the added antibiotics

All patients who received an antibiotic loaded calcium sulphate carrier (Stimulan, Biocomposites, Keele, UK) for either confirmed infection, presumed infection or for prophylaxis between July 2015 and July 2020 were included. Stimulan use was at the discretion of the surgeon, and between 10 and 40cc was used. In the absence of a known organism we routinely used 1g vancomycin and 240mg gentamicin per 10 cc of calcium sulphate. Post-operative sensitivities for all organisms cultured were compared to the antibiotics delivered locally. Persistent wound drainage was defined as discharge beyond the third postoperative day. Patients had serum calcium measured if they developed symptoms consistent with hypercalcaemia (Ca >2.6 mmol/L) or the clinical team felt they were at high risk.

189 patients (mean age 66.9 years, mean BMI 28.9, 85 male, 104 female) were included. 11 patients had a native joint septic arthritis, 42 presented with acute PJI and 136 presented with chronic PJI. 133 patients grew an organism, of which 126 were sensitive to the added antibiotics. Of the seven patients with resistant growth five had vancomycin-resistent Enterococcus, one Pseudomonas and one multi-organism growth including coagulase negative Staphylococcus. 40 patients experienced persistent wound discharge, with eight requiring re-operation. All other cases settled with dressing management. 12 patients developed hypercalcaemia (3/64 10cc, 7/117 20cc, 0/2 30cc and 2/6 40cc). The peak calcium reading ranged between the second and twelfth post-operative day.

The addition of vancomycin and gentamicin to absorbable calcium sulphate covers the majority of organisms found in culture positive infection in our cohort. It also appears safe, with an acceptable incidence of hypercalcaemia or wound discharge. Further work is required to identify patients at greatest risk of culturing resistant organisms or delayed wound healing.

Aims

The aim of this prospective cohort study was to evaluate the early migration of the TriFit cementless proximally coated tapered femoral stem using radiostereometric analysis (RSA).

INTRODUCTION

Hip resurfacing offers a more bone conserving solution than total hip replacement (THR) but currently has limited clinical indications related to some poor design concepts and metal ion related issues. Other materials are currently being investigated based on their successful clinical history in THR such as Zirconia Toughened Alumina (ZTA, Biolox Delta, CeramTec, Germany) which has shown low wear rates and good biocompatibility but has previously only been used as a bearing surface in THR. A newly developed direct cementless fixation all-ceramic (ZTA) resurfacing cup offers a new solution for resurfacing however ZTA has a Young's modulus approximately 1.6 times greater than CoCr - such may affect the acetabular bone remodelling. This modelling study investigates whether increased stress shielding may occur when compared to a CoCr resurfacing implant with successful known clinical survivorship.

Introduction

Antibiotic loaded absorbable calcium sulphate beads (ALCSB) are an increasingly popular adjunct in the treatment of musculoskeletal infections including osteomyelitis and peri-prosthetic joint infections (PJI). Limited data exist regarding the clinical indications and biochemical outcomes of ALCSB in PJI cases.

Introduction

We are a high-volume arthroplasty unit performing over 800 primary THRs annually at an approximate reimbursement of £6.5 million to the Trust. 70% are hybrid and we have been using the Taperfit - Trinity combination (Corin, Cirencester) since March 2016. We aimed to investigate the potential cost-savings and clinical benefits of instrument rationalisation using this system following GIRFT principles.

Background

Total hip arthroplasty (THA) is increasingly used for active patients with displaced intracapsular hip fractures. Dislocation rates in this cohort remain high postoperatively compared to elective practice, yet it remains unclear which patients are most at risk. The aim of this study was to determine the dislocation rate for these patients and to evaluate the contributing patient and surgeon factors.

INTRODUCTION

Unlike current acetabular cups, this novel ceramic cup has a Ti/HA coating which removes the requirement for assembly into a metal shell which avoiding potential chipping/misalignment and reducing wall thickness [Figure 1]. This study examines the resistance of novel thin-walled, direct to bone fixation ceramic cups to critical impact loads.

Aim

A number of orthopaedic strategies have been described for limb salvage following periprosethic joint infection (PJI). However, this is often only possible with concomitant soft tissue reconstruction in the form of flap coverage. The purpose of this study was to determine the long-term clinical outcome of patients who underwent pedicled gastrocnemius flap coverage as part of their treatment for knee PJI.

Aim

Debridement, antibiotics and implant retention (DAIR) is the recommended treatment for all acute prosthetic joint infections (PJI). However, the efficacy of DAIR and identification of risk factors for failure in patients with late acute PJI, is not well described.

Aims

The aim of this study was to determine the stability of a new short femoral stem compared with a conventional femoral stem in patients undergoing cementless total hip arthroplasty (THA), in a prospective randomized controlled trial using radiostereometric analysis (RSA).

Background

Short bone-conserving femoral stem implants were developed to achieve more physiological, proximal bone loading than conventional femoral stems. Concerns have arisen, however, that improved loading may be offset by lower primary stability because of the reduced potential area for bony contact.

Endoprosthetic replacement (EPR) is an available option for the management of massive bone loss around failed knee implants. The aim of this study was to determine the results of knee EPRs performed for non-tumour indications. Since 2007, 85 EPRs were performed for in a single tertiary centre by seven surgeons. Mean age at surgery was 73.5 years (range:35–95) with infection as the most common indication (49%), followed by aseptic loosening (18%), complex primary replacement (16%), fracture (15%) and mechanical failure (2%). Mean follow up was 4 years (range:1–9). Functional outcome was determined using the Oxford Knee Score (OKS). At follow-up, 21 patients were deceased and 2 lost to follow-up. Complication rate was 19%. Of the 7 infected cases, 6 were treated with DAIR (debridement, antibiotics, and implant retention) and one underwent above knee amputation. Four of the patients undergoing DAIR were cleared of infection and 2 are on long-term antibiotics. Accounting for implant revision, loss to follow-up and those on long-term antibiotics as failures, 5-year survival was 89% with an average OKS of 25 (SD=10). This mid-term study shows that distal femur EPR is a valuable option for the increasing burden of complex revision knee surgery

Aim

To assess the influence of route of antibiotic administration on patient-reported outcome measures (PROMS) of individuals treated for hip and knee infections in the OVIVA multi-centre randomised controlled trial.

Aim

Culture of multiple periprosthetic tissue samples is the current gold-standard for microbiological diagnosis of prosthetic joint infections (PJI). Additional diagnostic information may be obtained through sonication fluid culture of explants. These current techniques can have relatively low sensitivity, with prior antimicrobial therapy or infection by fastidious organisms particularly influencing culture results. Metagenomic sequencing has demonstrated potential as a tool for diagnosis of bacterial, viral and parasitic infections directly from clinical samples, without the need for an initial culture step. We assessed whether metagenomic sequencing of DNA extracts from sonication fluid can provide a sensitive tool for diagnosis of PJI compared to sonication fluid culture.

Aims

The aim of this study was to examine the real time in vivo kinematics of the hip in patients with cam-type femoroacetabular impingement (FAI).

There is a critical need for safe innovation in total joint replacements to address the demands of an ageing yet increasingly active population. The development of robust implant designs requires consideration of uncertainties including patient related factors such as bone morphology but also activity related loads and the variability in the surgical procedure itself. Here we present an integrated framework considering these sources of variability and its application to assess the performance of the femoral component of a total hip replacement (THR).

The framework offers four key features. To consider variability in bone properties, an automated workflow for establishing statistical shape and intensity models (SSIM) was developed. Here, the inherent relationship between shape and bone density is captured and new meshes of the target bone structures are generated with specific morphology and density distributions. The second key feature is a virtual implantation capability including implant positioning, and bone resection. Implant positioning is performed using automatically identified bone features and flexibly defined rules reflecting surgical variability. Bone resection is performed according to manufacturer guidelines. Virtual implantation then occurs through Boolean operations to remove bone elements contained within the implant's volume. The third feature is the automatic application of loads at muscle attachment points or on the joint contact surfaces defined on the SSIM. The magnitude and orientation of the forces are derived from models of similar morphology for a range of activities from a database of musculoskeletal (MS) loads. The connection to this MS loading model allows the intricate link between morphology and muscle forces to be captured. Importantly, this model of the internal forces provides access to the spectrum of loading conditions across a patient population rather than just typical or average values. The final feature is an environment that allows finite element simulations to be run to assess the mechanics of the bone-implant construct and extract results for e.g. bone strains, interface mechanics and implant stresses. Results are automatically processed and mapped in an anatomically consistent manner and can be further exploited to establish surrogate models for efficient subsequent design optimization. To demonstrate the capability of the framework, it has been applied to the femoral component of a THR.

An SSIM was created from 102 segmented femurs capturing the heterogeneous bone density distributions. Cementless femoral stems were positioned such that for the optimal implantation the proximal shaft axis of the femurs coincided with the distal stem axis and the position of the native femoral head centre was restored. Here, the resection did not affect the greater trochanter and the implantations were clinically acceptable for 10000 virtual implantations performed to simulate variability in patient morphology and surgical variation. The MS database was established from musculoskeletal analyses run for a cohort of 17 THR subjects obtaining over 100,000 individual samples of 3D muscle and joint forces. An initial analysis of the mechanical performance in 7 bone-implant constructs showed levels of bone strains and implant stresses in general agreement with the literature.

Aim

Advocates of Debridement-Antibiotics-and-Implant-Retention (DAIR) in hip peri-prosthetic joint infection (PJI) argue that a procedure not disturbing a sound prosthesis-bone interface is likely to lead to better survival and functional outcome compared to revision. However, no evidence supports this. This case-control study's aims were to compare outcome of DAIRs for infected 1° total hip arthroplasty (THA) with outcomes following 1° THA and 2-stage revisions of infected 1° THAs.

Introduction

The burden of peri-prosthetic joint infection (PJI) following hip and knee surgery is increasing. Endoprosthetic replacement (EPR) is an option for management of massive bone loss resulting from infection around failed lower limb implants.

Objectives

A possible solution for the management of proximal femoral bone loss is a modular femoral endoprosthesis (EPR). Although the outcome of EPRs in tumour surgery has been well described, the outcome of their use in revision hip surgery has received less attention. The aim of this study was to describe the outcome of using EPR for non-neoplastic indications.

Introduction

Native hip joint infection can result in hip arthrosis as a complication requiring the need for subsequent arthroplasty. There is little evidence to support single or staged THA. We present the results of patients who have undergone total hip arthroplasty (THA) following hip joint sepsis in our institution.

Image-guided intra-articular hip injection of local-anaesthetic and steroid is commonly used in the management of hip pain. It can be used as a diagnostic and/or therapeutic tool and is of low cost (£75). The aim of this study was to assess how often a hip injection has a therapeutic effect.

This is a retrospective, consecutive, case series of intra-articular hip injections performed in a tertiary referral hospital over a 2-year period (2013–4). Patients were identified from the radiology department's prospectively entered database. Clinical information, reason for injection and subsequent management was obtained from hospital records. All patients prospectively reported their pain levels in a numeric pain scale diary (out of 10) at various time points; pre-, immediately post-, 1st day-, 2nd day- and 2 weeks- post-injection. Only patients with complete pain scores at all time points were included (n=200, of the 250 injections performed over study period, 80%).

The majority of injections were performed for osteoarthritis (OA) treatment (82%). The pain was significantly reduced from a pre-injection score of 7.5 (SD:2) to 5.0 (SD:3) immediately post-injection(p<0.001); only 24 (11%) reported any worsening of pain immediately post-injection. Pain significantly reduced further to 3.8(SD:3) at 2-weeks post-injection (p<0.001). 50% of patients had at least a 3 point drop in reported pain. No improvement was seen in 18 patients and 10 (5%) reported worse pain at 2-weeks compared to pre-injection. Of the OA cohort, 10% have required repeat injections, 45% required no further intervention and 45% underwent or are due for hip replacement. No immediate complications occurred.

Intra-articular hip injection reduced pain in 86% of cases and has delayed any further surgical treatment for at least 2 years in over 50% of OA cases. It is hence a cost-effective treatment modality. Further work is necessary to describe factors predicting response.

The management of proximal femoral bone loss is a significant challenge in revision hip arthroplasty. A possible solution is the use of a modular proximal femur endoprosthesis (EPR). Although the survivorship and functional outcome of megaprostheses used in tumour surgery has been well described, outcome of EPRs used in revision hip surgery has received less attention. The aim of this study was to determine the 5-year outcome following proximal femur EPR and determine factors that influence it.

This was a retrospective consecutive case series of all EPRs (n=80) performed for non-neoplastic indications, by 6 surgeons, in our tertiary referral centre, between 2005–2014. Patient demographics and relevant clinical details were determined from notes. The most common indications for the use of EPRs included infection (n=40), peri-prosthetic fracture (n=12) and failed osteosynthesis of proximal femoral fractures/complex trauma (n=11). Outcome measures included complication and re-operation rates, implant survival and assessment of functional outcome using the Oxford-Hip-Score (OHS).

The mean age at surgery was 69 years and mean follow-up was 4 (0 – 11) years. The mean number of previous hip operations was 2.4 (range: 0 – 17). Twenty-five patients sustained a complication (31%), the most common being infection (n=9) and dislocation (n=4). By follow-up, further surgery was required in 18 (22%) hips, 9 of which were EPR revisions. 5-yr implant survivorship was 87% (95%CI: 76 – 98%). Mean OHS was 28 (range: 4 – 48). Inferior survival and outcome were seen in EPRs performed for the treatment of infection. Infection eradication was achieved in 34/41 with the index EPR procedure and in 40/41 hips by follow-up.

Limb salvage was achieved in all cases and acceptable complication- and re-operation rates were seen. EPRs for periprosthetic fractures and failed osteosynthesis had best outcome. We recommend the continued use of proximal femur EPR in complex revision surgery.

Introduction

The value of Debridement-Antibiotics-and-Implant-Retention (DAIR) in prosthetic-joint-infection (PJI) is still a matter of debate as most studies to-date are underpowered with variable end-points. In our, tertiary referral, bone infection unit we consider DAIR to be a suitable option in all PJIs with soundly fixed prostheses, despite chronicity. The aims of this study were to define the long-term outcome following DAIR in hip PJI and identify factors that influence it.

Collection of 4–5 independent peri-prosthetic tissue samples is recommended for microbiological diagnosis of prosthetic joint infections. Sonication of explanted prostheses has also been shown to increase microbiological yield in some centres. We compared sonication with standard tissue sampling for diagnosis of prosthetic joint and other orthopaedic device related infections.

We used standard protocols for sample collection, tissue culture and sonication. Positive tissue culture was defined as isolation of a phenotypically indistinguishable organism from ≥2 samples; and positive sonication culture as isolation of an organism at ≥50 cfu/ml. We compared the diagnostic performance of each method against an established clinical definition of infection (Trampuz 2011), and against a composite clinical and microbiological definition of infection based on international consensus (Gehrke & Parvizi 2013).

350 specimens were received for sonication, including joint prostheses (160), exchangeable components (76), other orthopaedic hardware and cement (104), and bone (10). A median of 5 peri-prosthetic tissue samples were received from each procedure (IQR 4–5). Tissue culture was more sensitive than sonication for diagnosis of prosthetic joint and orthopaedic device related infection using both the clinical definition (66% versus 57%, McNemar's Χ2 test p=0.016) and the composite definition of infection (87% vs 66%, p<0.001). The combination of tissue culture and sonication provided optimum sensitivity: 73% (95% confidence interval 65–79%) against the clinical definition and 92% (86–96%) against the composite definition.

Results were similar when analysis was confined to joint prostheses and exchangeable components; other orthopaedic hardware; and patients who had received antibiotics within 14 days prior to surgery.

Tissue sampling appears to have higher sensitivity than sonication for diagnosis of prosthetic joint and orthopaedic device infection at our centre. This may reflect rigorous collection of multiple peri-prosthetic tissue samples. A combination of methods may offer optimal sensitivity, reflecting the anatomical and biological spectrum of prosthetic joint and other device related infections.

Debridement, antibiotics and implant retention (DAIR) is a surgical option in the treatment of prosthetic joint infection (PJI). It is thought to be most appropriate in the treatment of early (≤6 weeks post-op) PJI. Most studies to-date reporting on DAIRs in hip PJI have been underpowered by reporting on small cohorts (n= <45), or report on registry data with associated biases and limitations. In our, tertiary referral, bone infection unit we consider DAIR to be a suitable option in all cases of PJI with a soundly fixed prosthesis, with early or late presentation, especially in patients who are too elderly or infirm to undergo major surgery.

Aim: To define the 10-year outcome following DAIR in hip PJI and identify factors that influence it.

We retrospectively reviewed all DAIRs performed in our unit between 1997 and 2013 for hip PJI. Only infected cases confirmed by histological and microbiological criteria were included. Data recorded included patient demographics and medical history, type of surgery performed (DAIR or DAIR + exchange of modular components), organism identified and type/duration of antibiotic treatment. Outcome measures included complications, mortality rate, implant survivorship and functional outcome.

121 DAIRs were identified with mean age of 71 years (range: 33–97). 67% followed an index procedure of 1° arthroplasty. 53% included exchange of modular components. 60% of DAIRs were for early onset PJI. Isolated staphylococcus was present in 50% of cases and 25% had polymicrobial infection. At follow-up (mean:7 years, range: 0.3 – 18), 83 patients were alive; 5- and 10- year mortality rates were 15% and 35% respectively. 45% had a complication (persistence of infection: 27%, dislocation: 10%) and 40% required further surgery. Twenty hips have been revised to-date (17%). Performing a DAIR and not exchanging the modular components was associated with an almost 3× risk (risk ratio: 2.9) of subsequent implant failure (p=0.04). 10-yr implant survivorship was 80% (95%CI: 70 – 90%). Improved 10-year implant survivorship was associated with DAIR performed for early PJI (85% Vs 68%, p=0.04). Functional outcome will be discussed.

DAIR is a particularly valuable option in the treatment of hip PJI, especially in the early post-operative period. Whenever possible, exchange of modular implants should be undertaken, however DAIRs are associated with increased morbidity even in early PJI. Factors that predict success of DAIR in late PJI need to be identified.

Periprosthetic femoral fracture (PFF) is a potentially devastating complication after total hip arthroplasty, with historically high rates of complication and failure because of the technical challenges of surgery, as well as the prevalence of advanced age and comorbidity in the patients at risk.

This study describes the short-term outcome after revision arthroplasty using a modular, titanium, tapered, conical stem for PFF in a series of 38 fractures in 37 patients.

The mean age of the cohort was 77 years (47 to 96). A total of 27 patients had an American Society of Anesthesiologists grade of at least 3. At a mean follow-up of 35 months (4 to 66) the mean Oxford Hip Score (OHS) was 35 (15 to 48) and comorbidity was significantly associated with a poorer OHS. All fractures united and no stem needed to be revised. Three hips in three patients required further surgery for infection, recurrent PFF and recurrent dislocation and three other patients required closed manipulation for a single dislocation. One stem subsided more than 5 mm but then stabilised and required no further intervention.

In this series, a modular, tapered, conical stem provided a versatile reconstruction solution with a low rate of complications.

Cite this article: Bone Joint J 2015;97-B:1031–7.

Aims

Femoroacetabular Junction Impingement (FAI) describes abnormalities in the shape of the femoral head–neck junction, or abnormalities in the orientation of the acetabulum. In the short term, FAI can give rise to pain and disability, and in the long-term it significantly increases the risk of developing osteoarthritis. The Femoroacetabular Impingement Trial (FAIT) aims to determine whether operative or non-operative intervention is more effective at improving symptoms and preventing the development and progression of osteoarthritis.

The orientation of the acetabular component is influenced not only by the orientation at which the surgeon implants the component, but also the orientation of the pelvis at the time of implantation. Hence, the orientation of the pelvis at set-up and its movement during the operation, are important. During 67 hip replacements, using a validated photogrammetric technique, we measured how three surgeons orientated the patient’s pelvis, how much the pelvis moved during surgery, and what effect these had on the final orientation of the acetabular component. Pelvic orientation at set-up, varied widely (mean (± 2, standard deviation (sd))): tilt 8° (2sd ±32), obliquity –4° (2sd ±12), rotation –8° (2sd ±14). Significant differences in pelvic positioning were detected between surgeons (p < 0.001). The mean angular movement of the pelvis between set-up and component implantation was 9° (sd 6). Factors influencing pelvic movement included surgeon, approach (posterior >  lateral), procedure (hip resurfacing > total hip replacement) and type of support (p < 0.001). Although, on average, surgeons achieved their desired acetabular component orientation, there was considerable variability (2sd ±16) in component orientation. We conclude that inconsistency in positioning the patient at set-up and movement of the pelvis during the operation account for much of the variation in acetabular component orientation. Improved methods of positioning and holding the pelvis are required.

Cite this article: Bone Joint J 2014; 96-B:876–83.

Introduction:

We report our 10-year experience of post-operative complications of calcaneal fractures treated by internal fixation and attempt to correlate these with previously cited patient risk factors.

Introduction:

Total ankle replacement is a recognised treatment for disabling end stage ankle arthritis and an alternative to arthrodesis, although results are not yet comparable to other joint replacements. This has stimulated a constant evolution in design of implants and instrumentation. The Nottingham Foot and Ankle Unit used the STAR until 2005, when it switched to Mobility, due to the perceived advantages of less bone resection, improved instrumentation and potentially less polyethylene insert wear. The aim of this study is to report the unit's results and review the different outcomes between the two ankle replacements used.

Introduction:

Calcaneal fractures are rare but debilitating injuries assumed to affect particular demographic sub groups. This study aimed to relate epidemiological factors (age, gender, smoking status and social deprivation scores) to the incidence of calcaneal fractures requiring operative fixation over a 10-year period.

Introduction:

Novel biomaterials may offer alternatives to metal arthroplasty bearings. To employ these materials in thin, bone conserving implants would require direct fixation to bone, using Titanium/HA coatings. Standard tests are used to evaluate the adhesion strength of coatings to metal substrates [1], versus FDA pass criteria [2]. In tensile adhesion testing, a disc is coated and uniform, uniaxial tension is exerted upon the coating-substrate interface; the strength is calculated from the failure load and surface area. Rapid failure occurs when the peak interface stress exceeds the adhesion strength, as local failure will propagate into an increasing tensile stress field.

Ceramics and reinforced polymers (e.g. carbon-fibre-reinforced PEEK), have considerably different stiffness (E) and Poisson's Ratio (ν) from the coating and implant metals. We hypothesised that this substrate-coating stiffness mismatch would produce stress concentrations at the interface edge, well in excess of the uniform stress experienced with coatings on similar stiffness metals.

Representative pre-clinical analysis is essential to ensure that novel prosthesis concepts offer an improvement over the state-of-the-art. Proposed designs must, fundamentally, be assessed against cyclic loads representing common daily activities [Bergmann 2001] to ensure that they will withstand conceivable in-vivo loading conditions. Fatigue assessment involves:

–

cyclic mechanical testing, representing worst-case peak loads encountered in-vivo, typically for 10 million cycles, or

Cyclic stresses from gait loading are super-imposed upon residual assembly stresses. In thick walled devices, the residual component is small in comparison to the cyclic component, but in thin section, bone preserving devices, residual assembly stresses may be a multiple of the cyclic stresses, so a different approach to fatigue assessment is required.

Modular devices provide intraoperative flexibility with minimal inventories. Components are assembled in surgery with taper interfaces, but resulting residual stresses are variable due to differing assembly forces and potential misalignment or interface contamination. Incorrect assembly can lead to incomplete seating and dissociation [Langdown 2007], or fracture due to excessive press-fit stress or point loading [Hamilton 2010]. Pre-assembly in clean conditions, with reproducible force and alignment, gives close control of assembly stresses. Clinical results indicate that this is only a concern with thick sectioned devices in a small percentage of cases [Hamilton 2010], but it may be critical for thin walled devices.

A pre-clinical analysis method is proposed for this new scenario, with a case study example: a thin modular cup featuring a ceramic bearing insert and a Ti-6Al-4V shell (Fig. 1). The design was assessed using FE predictions, and manufacturing variability from tolerances, surface finish effects and residual stresses was assessed, in addition to loading variability, to ensure physical testing is performed at worst case:

–

assembly loads were applied, predicting assembly residual stress, verified by strain gauging, and a range of service loads were superimposed.

The predicted worst-case stress conditions were analysed against three ‘constant life’ limits [Gerber, 1874, Goodman 1899, Soderberg 1930], a common aerospace approach, giving predicted safety factors. Finally, equivalent fatigue tests were conducted on ten prototype implants.

Taking a worst-case size (thinnest-walled 48 mm inner/58 mm outer), under assembly loading the peak tensile stress in the titanium shell was 274 MPa (Fig. 2). With 5kN superimposed jogging loading, at an extreme 75° inclination, 29 MPa additional tensile stress was predicted. This gave mean fatigue stress of 288.5 MPa and stress amplitude of 14.5 MPa (R=0.9). Against the most conservative infinite life limit (Soderberg), the predicted safety factor was 2.40 for machined material, and 2.03 for forged material, or if a stress-concentrating surface scratch occurs during manufacturing or implantation (Fig. 3). All cups survived 10,000,000 fatigue cycles.

This study employed computational modelling and physical testing to verify the strength of a joint prosthesis concept, under worst case static and fatigue loading conditions. The analysis technique represents an improvement in the state of the art where testing standards refer to conventional prostheses; similar methods could be applied to a wide range of novel prosthesis designs.

Objectives

The number of surgical procedures performed each year to treat femoroacetabular impingement (FAI) continues to rise. Although there is evidence that surgery can improve symptoms in the short-term, there is no evidence that it slows the development of osteoarthritis (OA). We performed a feasibility study to determine whether patient and surgeon opinion was permissive for a Randomised Controlled Trial (RCT) comparing operative with non-operative treatment for FAI.

Introduction

Hip arthroscopy is a relatively new procedure and evidence to support its use remains limited. Well-designed prospective clinical trials with long-term outcomes are required, but study design requires an understanding of current practice. Our aim was to determine temporal trends in the uptake of non-arthroplasty hip surgery in England between 2001 and 2011.

Introduction

Since the introduction of 3rd generation Metal-on-Metal-Hip-Resurfacing-Arthroplasty (MoMHRA), thousands of such prostheses have been implanted worldwide in younger patients with end-stage hip osteoarthritis. However, no independent centre has reported their medium-to-long term outcome. The aim of this study is to report the ten year survival and outcome of the Birmingham Hip Resurfacing (BHR), the most commonly used MoMHRA worldwide.

INTRODUCTION

Resurfacing prostheses are implanted by impaction onto the prepared femoral head. Ceramic resurfacings can be proposed as an alternative to metal implants, combining bone conservation with mitigation of sensitivity reaction risks. With low wall-thickness required for bone conservation, their strength must be verified. This study aimed to assess a ceramic resurfacing prosthesis' strength under surgical loads using a computational model, tuned and verified with physical tests.

Introduction

Comminuted mid-foot fractures are uncommon. Maintenance of the length and alignment of the medial column, with restoration of articular surface congruity, is associated with improved outcomes. Conventional surgery has utilised open or closed reduction with K-wire fixation, percutaneous techniques, ORIF, external fixation or a combination of these methods.

In 2003 temporary bridge plating of the medial column was described to reconstruct and stabilise the medial column. The added advantage of locking plates is the use of angle-stable fixation. We present our experience with temporary locking plates in complex mid-foot fractures.

Introduction: Metal-on-metal-hip-resurfacing-arthroplasty (MoMHRA) has been associated with the development of inflammatory pseudotumours(IP), especially in females. IPs have been linked to wear debris, which can be related to metal-ion blood levels. Acetabular component position has been shown to influence wear. We have identified an optimum component orientation minimising IP risk around an inclination/anteversion of 40°/20°±10°. Our aim was to see if this optimal position results in lower metal ions and to identify the boundary of an optimal placement zone for low wear.

Methods: A cohort of 104 patients(60M:44F) with unilateral MoMHRA was studied. Blood tests were obtained at a mean follow up of 3.9 years and serum Co/Cr levels were measured(ICPMS). High metal ion concentrations were defined as Co> 4.1ppb and Cr> 5.2ppb. Radiographic cup inclination/anteversion were measured using EBRA. The differences in ion levels between different orientation zones were investigated. Three orientation zones were defined centered on 40°/20°: Z1-within ±5°, Z2-outside ±5°/within ±10° and Z3-within ±10°.

Results: There was a wide range of cup placements. Females had significantly (p< 0.001) smaller components(mean:51, 44–60) than males(mean: 56, 52–64). Cr levels, but not Co, were higher in females(p=0.002) and those with small femoral components(< 50mm, p =0.03). Patients with cups within Z1 (n=13) had significantly lower Co(p=0.005) and Cr(p=0.001). Males with cups within Z3(n=27) had lower ion levels in comparison to those outside, which were significantly lower for Co(p=0.049) but not Cr(p=0.084). Females had similar ion levels within and out of Z3(Cr/Co: p=0.83/0.84). Co levels were significantly lower in Z1(n=13) in comparison to Z2(n=33)(p=0.048) but Cr levels were not different (p=0.06).

Discussion: MoMHRA cups placed within ±5° of the optimum(40°/20°) had significantly lower metal ions indicating lower wear within this narrow zone. This safe zone, could extend to ±10° for males only. The narrower safe zone coupled with smaller components implanted are possible factors contributing to the increased IP incidence seen in females.

Introduction: The use of highly cross-linked polyethylene (HXLPE) is now commonplace for total hip arthroplasty, however there is no long-term data to support its use. Hip simulator studies suggest that the wear rate of some types of HXLPE is ten times less than conventional polyethylene (UHMWPE). The outcomes of hip simulator studies are not always reproduced in vivo and there is some evidence that HXLPE wear may increase between 5 and 7 years.

Method: A prospective double blind randomised control trial was conducted using Radiostereometric Analysis (RSA). Fifty-four subjects were randomised to receive hip replacements with either UHMWPE liners or HXLPE liners. All subjects received a cemented CPT stem and uncemented Trilogy acetabular component (Zimmer, Warsaw, IN, USA). The 3D penetration of the head into the socket was determined to a minimum of 7 years.

Results: The total liner penetration was significantly different at 7 years (p=0.005) with values of 0.33 mm (SE 0.05 mm) for the HXLPE group and 0.55 mm (SE 0.05 mm) for the UHMWPE group. The steady state wear rate from 1 year onwards was significantly lower for HXLPE (0.005 mm/yr, SE 0.007 mm/yr) than for UHMWPE (0.037 mm/yr, SE 0.009 mm/yr) (p=0.007). The direction of wear was supero-lateral.

Discussion: We have previously demonstrated that the penetration in the first year is creep-dominated, from one year onwards the majority of penetration is probably due to wear. This study confirms the predictions from hip simulator studies which suggest that the wear rate of this HXLPE approaches that of metal-on-metal and ceramic-on-ceramic articulations. HXLPE may have the potential to reduce the need of revision surgery, due to wear debris induced osteolysis. It may also enable surgeons to use larger couples, thus reducing the risk of impingement and dislocation.

Introduction: Metal on metal hip resurfacing arthroplasty(MoMHRA) is an alternative option to THR in the treatment of young adults with OA. A recognised MoMHRA complication is the development of an inflammatory pseudotumour(IP). Diagnosis is made with the aid of US and/or MRI. To-date, no radiographic indication of the presence of IP has been identified. Neck thinning is a recognised phenomenon in MoMHRA hips not associated with any adverse clinical events. Its pathogenesis is considered multi-factorial. Our aim was to establish whether excessive neck narrowing is associated with the presence of a pseudotumour.

Methods: Twenty-seven hips (26 patients) with IP confirmed clinically, radiologically, intra-operatively and histologically were matched for sex, age, pre-operative diagnosis, component size and follow-up with an asymptomatic MoMHRA cohort (Control n=60). For all patients, prosthesis-neck-ratio(PNR) was measured on plain AP pelvic radiographs post-operatively and at follow-up as previously described and validated.

Results: All IP patients (4M:23F) and all (12M:48F) but two controls had a posterior approach at the time of MoMHRA. Post-operatively, there was no difference in the PNR between the two groups (p=0.19). At an average follow up of 3.5 years (range:0.7–8.3), IP patients(mean 1.26, 1.10–1.79) had a significantly higher (p< 0.0001) PNR in comparison to their controls(mean 1.14, 1.03–1.35). Greater neck narrowing occurred in both genders. IP necks had narrowed by an average of 8% (range:3–23). The degree of neck narrowing was correlated with length of survival of implant (p=0.001).

Discussion: This study shows a strong association between IP and neck narrowing. Processes such as impingement and increased wear are considered to be involved in the pathogenesis of both IP and neck narrowing. Furthermore, the presence of an IP, could lead to altered vascularity via a mass effect and further contribute to neck narrowing. Neck narrowing in symptomatic MOMHRA patients should alert surgeons of the possible presence of IP.

Although resurfacing hip replacement (RHR) is associated with a more demanding patient cohort, it has achieved survivorship approaching that of total hip replacement. Occasional failures from femoral neck fracture, or migration and loosening of the femoral head prosthesis have been observed, the causes of which are multifactorial, but predominately biomechanical in nature. Current surgical technique recommends valgus implant orientation and reduction of the femoral offset, reducing joint contact force and the femoral neck fracture risk. Radiographic changes including femoral neck narrowing and ‘pedestal lines’ around the implant stem are present in well performing hips, but more common in failing joints indicating that loosening may involve remodelling. The importance of prosthesis positioning on the biomechanics of the resurfaced joint was investigated using finite element analysis (FEA).

Seven FE models were generated from a CT scan of a male patient: the femur in its intact state, and the resurfaced femur with either a 50mm or 52mm prosthesis head in

neutral orientation,

The fracture risk during trauma was investigated for stumbling and a sideways fall onto the greater trochanter, by calculating the volume of yielding bone. Remodelling was quantified for normal gait, as the percentage volume of head and neck bone with over 75% post-operative change in strain energy density for an older patient, and 50% for a younger patient.

Resurfacing with the smaller, 50mm prosthesis reduced the femoral offset by 3.0mm, 4.3mm and 5.1mm in varus, neutral and valgus orientations. When the 52mm head was used, the natural joint centre could be recreated rrespective of orientation, without notching the femoral neck. The 50mm head reduced the volume of yielding femoral neck bone relative to the intact femur in a linear correlation with femoral offset. When the natural femoral offset was recreated with the 52mm prosthesis, the predicted neck fracture load in stumbling was decreased by 9% and 20% in neutral and varus orientations, but remained in line with the intact bone when implanted with valgus orientation. This agrees with clinical experience and justifies currently recommended techniques. In oblique falling, the neck fracture load was again improved slightly when the femoral offset was reduced, and never fell below 97% of the natural case for the larger implant in all orientations.

Predicted patterns of remodelling stimulus were consistent with radiographic clinical evidence. Stress shielding increased slightly from varus to valgus orientation, but was restricted to the superior femoral head in the older patient. Bone densification around the stem was predicted, indicating load transfer. Stress shielding only extended into the femoral neck in the young patient and where the femoral offset was reduced with the 50mm prosthesis. The increase in remodelling correlated with valgus orientation, or reduced femoral offset. The trend would become more marked if this were to reduce the joint contact force, but there was no such correlation for the 52mm prosthesis, when the natural femoral offset was recreated. Only in extreme cases would remodelling alone be sufficient to cause visible femoral neck narrowing, i.e. patients with a high metabolism and considerably reduced femoral offset, implying that other factors including damage from surgery or impingement, inflammatory response or retinacular blood supply interruption may also be involved in femoral neck adaptation.

The results of this FEA biomechanical study justify current surgical techniques, indicating improved femoral neck fracture strength in stumbling with valgus position. Fracture risk under oblique falling was less sensitive to resurfacing. Furthermore, the results imply that reduced femoral offset could be linked to narrowing of the femoral neck; however the effects of positioning alone on bone remodelling may be insufficient to account for this. The study suggests that surgical technique should attempt to recreate the natural head centre, but still aim primarily for valgus positioning of the prosthesis, to reduce the femoral neck fracture risk.

The Acoustic Emission (AE) technique has been described as possessing ‘many of the qualities of an ideal damage-monitoring technique’, and the technique has been used successfully in recent years to aid understanding of failure mechanisms and damage accumulation in bone cement during de-bonding of the cement-metal interface fatigue loading, pre-load cracking during polymerisation and to describe and locate damage within an entire stem construct. However, most investigations to date have been restricted to in-vitro testing using surface mounted sensors. Since acoustic signals are attenuated as they travel through a material and across interfaces, it is arguable that mounting the sensors on the bone surface to investigate damage mechanisms occurring within the bone cement layer is not ideal. However, since direct access to the bone cement layer is not readily available, the bone surface is often the only practical option for sensor positioning.

This study has investigated the potential for directly embedding AE sensors within the femoral stem itself. This enables a permanent bond between the sensor and structure of interest, allows closer proximity of the sensor to the region of interest, and eliminates potential complications and variability associated with fixing the sensor to the sample. Data is collected during in-vitro testing of nominal implanted constructs, and information from both embedded and externally mounted AE sensors are compared and corroborated by microComputed Tomography (micro-CT) images taken both before and after testing.

The use of multiple AE sensors permitted the location as well as the chronology of damage events to be obtained in real time and analysed without the need for test interruption or serial sectioning of the test samples. Parametric analysis of the AE signal characteristics enabled those events likely to be associated with cracking as opposed to interfacial rubbing or de-bonding to be differentiated and it was shown that the embedded sensors gave a closer corroboration to observed damage using micro-CT and were less affected by unwanted sources of noise.

The results of this study have significant implications for the use of AE in assessing the state of total hip replacement (THR) constructs both in-vitro and potentially in-vivo. Incorporating the sensors into the femoral stem during in-vitro testing allows for greater repeatability between tests since the sensors themselves do not need to be removed and re-attached to the specimen. To date, all in-vivo studies attempting to use the AE technique to monitor the condition of any replacement arthroplasty device have used externally mounted sensors and suffered from the attenuation of acoustic information through flesh and skin. It is hypothesised that the use of directly embedded AE sensors may provide the first steps towards an in-vivo, cost effective, user friendly, non-destructive system capable of continuously monitoring the condition of the implanted construct and locating the earliest incidences of damage initiation.

Metal on metal hip resurfacing (MMHR) is a popular procedure for the treatment of osteoarthritis in young patients. Several centres have observed masses, arising from around these devices, we call these inflammatory pseudotumours. They are locally invasive and may cause massive soft tissue destruction. The aim of this study was to determine the incidence and risk factors for pseudotumours that are serious enough to require revision surgery.

In out unit, 1,419 MMHRs were performed between June 1999 and November 2008. All revisions were identified, including all cases revised for pseudotumour. Pseudotumour diagnosis was made by histological examination of samples from revision. A Kaplan-Meier survival analysis was performed, Cox regression analysis was used to estimate the independent effects of different factors.

The revision rate for pseudotumour increased with time and was 4% (95% CI: 2.2% to 5.8%) at eight years. Female gender was a strong risk factor: at eight years the revision rate for pseudotumours in men was 0.5% (95% CI 0% to 1.1%), in women over 40 it was 6% (95% CI 2.3% to 10.1%) and in women under 40 it was 25% (95% CI 7.3% to 42.9%) (p< 0.001). Other factors associated with an increase in revision rate were, small components (p=0.003) and dysplasia (p=0.019), whereas implant type was not (p=0.156).

We recommend that resurfacings are undertaken with caution in women, especially those younger than 40 years of age, but they remain a good option in men. Further work is required to understand the patho-aetiology of pseudotumours so that this severe complication can be avoided.

Aims: Reverse oblique intertrochanteric fractures (OTA/ AO 31-A3) have unique biomechanical properties that confer difficulties in obtaining stable fixation with the conventional sliding dynamic condylar screw. Recent studies have recommended the use of cephalocondylic intramedullary devices for these unstable fractures. Both the Proximal Femoral Nail (PFN) and the Gamma Nail (GN) have shown good outcome results but the results of treatment with the IMHS have not been reported in the literature.

Methods: Between 1999–2008 6724 consecutive hip fractures were treated at our institute. There were 2586 extracapsular fractures and 307 subtrochanteric fractures. 115 of the extracapsular fractures had a reverse oblique pattern and 63 of these were treated with the IMHS. We retrospectively reviewed clinical and radiological records for the reverse oblique intertrochanteric fractures treated with the IMHS. Follow-up duration ranged from 8 months to 6 years.

Results: Among the 63 patients treated with the IMHS, 56 (88%) fractures were reduced satisfactorily with only one poorly positioned hip screw in the femoral head. There were no cases of femoral shaft fracture, screw cut-out or collapse at the fracture site. The orthopaedic complications were two cases of mal-rotation, two cases of non-union, two cases of distal locking bolts backing out, and one cracked nail. 30 day mortality was 6.5%.

Conclusion: Cephalo-medullary nailing devices have been recommended for the treatment of reverse oblique intertrochanteric femoral fractures. Our clinical and radiological outcomes with the IMHS compare favourably to the results in reports where other cephalo-medullary devices have been used. Therefore we consider the IMHS a good option for the treatment of these unstable fractures.

Introduction: Metal-on-metal hip resurfacing arthroplasty (MoMHRA) has gained popularity as an alternative to THR for younger patients with osteoarthritis. A growing concern has been the association of MoMHRA with the development of inflammatory pseudotumours (IP), especially in women. These have been linked to metal-on-metal wear, which can be related to metal ion concentrations. Elevated metal wear debris levels may result from impingement, rim contact and edge loading. Head-neck ratio (HNR) is a predetermining factor for range of movement and impingement. Neck thinning is a recognised phenomenon post-MoMHRA and we have found an association of IP with increased neck thinning based on a case control study. Our aims were to identify HNR changes a hip undergoes when resurfaced and at follow up; and whether greater neck thinning at follow-up could be associated with the presence of elevated metal ions.

Methods: A cohort of 91 patients (57M:34F) with unilateral MoMHRAs were included in this study. Blood tests were obtained at a mean follow up of 3.9 years (range 1.7–7 years) and serum (Co:Cr) ion levels were measured (ICPMS). High metal ion concentrations were defined as Co> 4.1ppb and Cr> 5.2ppb. For all patients, head-neck ratio (HNR) was measured on plain anterio-posterior pelvic radiographs pre-operatively, immediately post-operatively and at follow-up.

Results: Female patients had significantly bigger HNR pre-op (mean=1.35, range:1.22–1.64) compared to males(mean=1.22, range:1.05–1.38) (p< 0.01). Immediately post-op, female HNRs (mean: 1.26, range: 1.14–1.34) were not different to male patients(mean=1.24, range=1.11–1.38) (p=0.11). At follow-up HNR was once again significantly bigger (p< 0.01) in females (mean=1.35, range: 1.21–1.49), compare to males (mean=1.27, range:1.11–1.38). HNR alterations with operation (p=0.00) and at follow-up (p< 0.01) were significantly bigger in female patients. Furthermore, there was a significant correlation between high ion levels and HNR change at follow-up for both Co (p=0.02) and Cr (p< 0.01).

Conclusion: This study identified gender-specific changes in HNR that resurfaced hips undergo, not previously documented. Female hips have greater HNR pre-operatively, compared to male hips, and appear to be biomechanically disadvantaged when resurfaced. A decrease in HNR with resurfacing could result in impingement and lead to processes, known to be more prevalent in females, such as neck thinning, increased wear and IP development. In addition, we highlight a correlation between high ion levels and greater neck thinning at follow-up. Increased neck thinning in symptomatic MoMHRA hips could be secondary to increased wear and should be investigated further radiologically for the presence of IP.

Introduction: Traditionally Short arm plaster casts have been used to treat distal radius fractures. Judging adequacy of immobilisation has never been defined. A significant proportion of these fractures loose reduction due to inadequate immobilisation. A new non-invasive external fixator technology has been introduced to address the shortcomings of plaster casts. Aim: Is the new non invasive fixator better at reducing skin device interface movement, than conventional plasters.

Materials and Methods: A prospective healthy volunteer study involving application of Short arm plaster of Paris cast, fibreglass cast and a new device Cambfix non-invasive wrist fixator with 15 forearms in each group, was undertaken. IRB approval and informed consent obtained from the volunteers. Colle’s type cast configuration was used. Displacement at the skin-cast and skin-new device interface was measured at proximal and distal ends. Maximal displacements noted immediately after application and after a specified intervals. Casts were windowed at the end of experiment and Cast index and Gap index were measured as ratios at the time of removal of casts. Statistical analysis was done using T-test and SPSS.

Results: The non-invasive Cambfix fixator showed less mean displacement at both the proximal and distal parts compared to plaster and fibreglass casts (p< 0.01). The mean gap index for the Cambfix device was 0.09, which was statistically significantly less than 0.15 and 0.14 for Plaster of Paris and fibreglass casts respectively (p< 0.01). Casts with higher gap index showed increased displacement, however cast index was less predictive of skin-cast displacement.

Conclusions: Skin-device interface movement was significantly better reduced with the Cambfix non-invasive fixator as compared with Short arm plaster of Paris and fibreglass casts. Lesser gap index is known to provide less interface movement. The Cambfix non-invasive fixator appears to achieve a better gap index more consistently. Limitations include healthy volunteer group, and relatively small numbers.

Introduction: Despite the satisfactory short-term implant survivorship of MoM hip resurfacing arthroplasty, symptomatic abnormal periprosthetic soft-tissue masses relating to the hip joint, ‘pseudotumours’, are being increasingly reported. These were found be locally destructive, requiring revision surgery in 75% of patients. Asymptomatic pseudotumours have not been previously investigated.

Methods: The aims were: (1) to investigate the prevalence of asymptomatic pseudotumours; and (2) to investigate their potential association with the level of metal ions. A total of 160 hips in 123 patients with a mean age 56 years (range 33–73) were evaluated at a mean follow-up of 61 months (range 13–88). Radiographs and OHS were assessed. Patients with a cystic or solid mass detected on the ultrasound/MRI had an aspiration or biopsy performed. Cobalt and chromium levels were analysed using Inductively-Coupled Plasma Spectrometer.

Results: Pseudotumours were found in 6 patients (5F: 1M). In 80% of bilateral cases, it was found in both sides. Histological examination showed extensive necrosis and diffuse lymphocyte infiltration. The presence of pseudotumour was associated with higher serum cobalt (9.2 μg/L vs. 1.9μg/L, p< 0.001) and chromium levels (12.0μg/L vs. 2.1μg/L, p< 0.001); higher hip aspirate cobalt (1182 μg/L vs. 86.2μg/L, p=0.003) and chromium levels (883μg/L vs. 114.8μg/L, p=0.006); and with inferior OHS (23 vs. 14 p=0.08).

Discussion: The prevalence of asymptomatic pseudotumour (5%) was higher than previously reported for the symptomatic pseudotumours (1%). There was a sixfold elevation of serum and a twelve-fold elevation of hip aspirate levels of cobalt and chromium in patients with pseudotumours. This suggests that pseudotumours may be a biological consequence of the large amount of metal debris generated in vivo. The association between pseudotumour and elevated metal ion levels might theoretically be explained by either systemic hypersensitivity responses to metal ions or local cytotoxic effects due to a high level of metal ions.

Introduction: Total hip replacement (THR) and total knee replacement (TKR) are widely accepted as effective surgical procedures to alleviate chronic joint pain and improve functional ability. Clinical evidence suggests that joint replacement results in excellent outcomes. Traditionally, reporting of outcomes has been focused on implant survivorship and surgeon based assessment of objective outcomes, such as range of motion, knee stability and radiographic results. However, because there is a discrepancy between patient and clinician ratings of health, patient-reported outcome measures have been validated to allow patients to rate their own health, thereby placing them at the centre of outcome assessment. The aim of this study was to compare the mid-term functional outcomes of TKR and THR using validated patient-reported outcome measures.

Methods: A cross-sectional postal audit survey of all consecutive patients who had a primary, unilateral THR or TKR at the Avon Orthopaedic Centre 5–8 years previously was conducted. Participants completed an Oxford hip score (OHS) or Oxford knee score (OKS). The Oxford questionnaires are self-report joint-specific measures that assess functional ability and pain from the patient’s perspective. They consist of 12 questions about pain and physical limitations experienced over the past four weeks because of the hip or knee.

Results: 1112 THR patients and 613 TKR patients returned a completed questionnaire, giving a response rate of 72%. The median OKS of 26 was significantly worse than the median OHS of 19 (p< 0.001). TKR patients experienced a poorer functional outcome than THR patients on all domains assessed by the Oxford questionnaire, independent of age. The percentage of patients reporting moderate-severe pain was two-fold greater for TKR than THR patients (26% vs 13%, respectively).

Conclusion: This survey found that TKR patients report more pain and functional limitations than THR patients at 5–8 years post-operatively, independent of age. The finding that over a quarter of TKR patients reported moderate-severe pain at 5–8 years post-operative indicates that a large proportion of people are undergoing major knee surgery that is failing to achieve its primary aim of pain relief. This raises questions about whether patient selection for TKR is appropriate. To improve patient selection, it may be necessary to have a preoperative screening protocol to identify patient factors predictive of a poor outcome after TKR. Currently, no such protocol exists and this is an area of orthopaedics requiring further research.

Introduction: Although THR can provide excellent pain relief and restore functional ability for most patients, there is a proportion of patients who experience a poor functional outcome after THR. One factor that could contribute to a poor outcome after THR is leg length discrepancy (LLD). Restoration of leg length is important in optimising hip biomechanics and LLD has several consequences for the patient, including back pain and a limp. Assessment of LLD using radiographs is time consuming and labour intensive, and therefore limits large scale studies of LLD. However, patients self-report of perceived LLD may be a useful tool to study LLD on a large scale. Therefore, the aim of this postal audit survey was to determine the prevalence of patient-perceived LLD after primary THR and its impact on mid-term functional outcomes.

Methods: A cross-sectional postal audit survey of all consecutive patients who had a primary, unilateral THR at the Avon Orthopaedic Centre 5–8 years previously was conducted. Several questions about LLD were included on the questionnaire. Firstly, patients were asked if they thought that their legs were the same length. For those who thought their legs were different lengths, they were asked if the difference bothered them, whether the difference in length leg was enough to comment upon, and whether they used a shoe raise. Participants also completed an Oxford hip score (OHS), which is a self-report measure that assesses functional ability and pain after THR, including limping

Results: 1,114 THR patients returned a completed questionnaire, giving a response rate of 73%. 329 patients (30%) reported that they thought their legs were different lengths. The median OHS for patients with a perceived LLD was 22, which was significantly worse than the OHS of 18 for patients who thought their legs were the same length (p< 0.001). Of the 329 patients with a perceived LLD, 161 patients (51%) were bothered by the difference, 65 patients (20%) thought the discrepancy was sufficient to comment upon and 101 patients (31%) used a shoe raise. 31% of patients with LLD limped most or all of the time compared to only 9% of patients without LLD.

Conclusion: In conclusion, this study found that the prevalence of perceived LLD at 5–8 years after THR was 30%. Of the patients with LLD, over 50% were bothered by the LLD and over a third used a shoe raise to equalise leg lengths. Patients with perceived LLD have a significantly poorer self-report functional outcome than those patients without LLD. It is therefore important that patients are informed pre-operatively of the high risk of LLD after THR and the associated negative impact this may have on their outcome.

Retrieval analysis offers a direct insight into in vivo wear mechanisms. However, the 3D measurement of wear patch characteristics on spherical highly reflective bearings has been difficult. An instrument based on an optical technique has been developed over the past 3 years. It is capable of scanning metallic head and cup in a single measurement, within minutes, at a resolution of 20 nm. From the cloud of 3D points obtained during scanning (typically 35,000 To 1,000,000), a 3D image of the measured part can be obtained. The associated computer program allows for sphericity, roughness, radius and local radius to be calculated, and surface maps of the 3D model can easily be plotted.

Both head and cup of two failed MoM resurfacing devices, a wear simulator test couple and intact components were analysed using the new technique. A successful McKee Farrar head (20 years in vivo) was also scanned. Results were compared with traces obtained on a Mitutoyo RA 300 roundness machine (resolution 0.01 microns).

3D maps of the bearing surfaces of MoM devices were obtained. The maximum linear wear values on heads were 2.5 microns, 99 microns 53.5 microns and 298 microns for the simulator sample, the McKee Farrar head and the two failed resurfacing devices respectively. The corresponding maximum linear wear values on cups were 11 microns, 529 microns and 645 microns for the simulator sample and the two failed resurfacing devices respectively. These results were in good agreement with results obtained on the Mitutoyo machine. Contrary to other worn samples, the two latter cups showed that the cup had worn on the edge of the bearing surface. This resulted in an oval shaped wear patch on the head. For the McKee Farrar device and the simulator device, the wear patch was away from the edge and the outline of the wear patch was circular in shape.

This novel technique has allowed for high resolution 3D mapping of the full bearing surfaces on successful McKee Farrar device and on more recent resurfacing devices. Further studies are required. However, the results suggest that component positioning is paramount to wear performance of metal on metal devices.

Aim: Lower friction in metal on metal (MOM) hip joints can reduce the wear, production of metal ions and loosening of acetabular cups. The effect of the fluid viscosity on the friction, especially in the relation to the physiological range, is still not fully investigated. The aim of this paper was to study the frictional behaviour of MOM hip joint within the human physiological fluid viscosities.

Materials and Methods: Friction measurement was carried out using a friction simulator on CoCrMo hip prostheses of 50 mm diameter with 100 and 200 micron diametral clearances. The samples were taken from a wear simulator test at 1.4, 2.3 and 3.2 million cycles. A dynamic loading of 100–2000N was applied to the femoral head with a movement of 1 Hz and +/−23 degree amplitude. Tests were performed using 25% new born calf serum which consisted of different ratios of serum and carboxymethyl cellulose with viscosities ranged from 0.0011 to 1.1 Pa s determined by a viscometer at a shear rate of 300/s.

Results: The friction of both clearances reduced with the progress of wear. In the lower range of viscosity, the friction of 100 micron clearance was lower than that of 200 micron clearance. However, when the viscosity reached the range of 0.01–0.06 Pa s, the friction of 100 micron clearance surpassed that of 200 micron clearance and this difference became wider with the increase of viscosity. During one measurement, the curves of 100 micron clearance started from low friction (≈0.05), but increased rapidly for all viscosities except the lowest of 0.001 Pa s. For the 200 micron clearance, the curves were stabilized when the viscosity was below 0.36 Pa s and low friction was observed as the viscosity increased. The friction started to increase only from 0.36 Pa s, but the gradient was less stiff compared to that of 100 micron clearance.

Discussion: Normal synovial fluid is non-Newtonian in nature with shear-rate dependent viscosity. Researchers have reported 300/s shear rate viscosities for normal, osteoarthritis, and inflammatory synovial fluids as 0.010.4, 0.0025–0.2 and 0.001–0.07 Pa s respectively. In this study, the 200 micron clearance had lower friction than that of 100 micron clearance in the majority of physiological viscosity range. Theoretical studies have suggested that smaller clearance and higher viscosity can benefit the lubrication in MOM bearings. However, this theory is valid if continuous and complete lubrication film is achieved. Small clearance and high viscosity may prevent the recovery of lubricant between cycles and cause depletion of lubricant, which can lead to direct contact of bearings and increase of friction. It is therefore concluded that the selection of clearance for MOM components should consider the human physiological fluid viscosities so that an optimal tribological performance can be achieved.

Acetabular cup orientation in hip arthroplasty is critical to prevent edge loading and impingement. Aerial alignment guides position the cup at a specified angle to the orthogonal planes, but only if the pelvis is in strict lateral-decubitus. Computer navigation can also be used to position the acetabular cup, but there are limitations associated with defining the pelvic reference plane. It can also be postulated that a fixed angle of inclination and anteversion is not suitable for every patient and every cup design. This paper describes the development and testing of instrumentation that allows patient specific acetabular cup placement without knowing the exact pelvic orientation.

Stage 1 determines the cup position during a trial reduction. A Judd nail retractor is left in the pelvis during the trial reduction. A single-use laser pointer is attached to the top of this nail, is free to move and can be locked in position. The trial acetabular cup has a handle protruding at a fixed angle from the face of the cup. At the end of this handle is another single-use laser pointer that projects a laser beam parallel to the axis of the cup onto the wall/ceiling. Keeping the handle parallel to the medio-lateral axis to control inclination angle, the leg is moved through a range of motion (ROM). The anteversion of the trial cup is adjusted until a position is found where flexion extension ROM is possible without impingement and satisfactory abduction-adduction is achieved with stability. Once this position is found, the Judd nail laser (fixed to the pelvis) is adjusted until its projected point, on the wall/ceiling, coincides with that from the trial handle. The Judd nail laser is then fixed in position, the hip dislocated and trial components removed.

Stage 2 aligns the definitive acetabular cup. The introducer has a laser pointer pointing parallel to its axis (away from the patient) and is attached to the definitive cup. The definitive cup is placed in the acetabulum and the introducer adjusted until its projected laser coincides with that from the Judd nail. The cup is then in the same orientation as determined during the trial reduction and can be impacted.

To demonstrate the accuracy of the laser alignment method, the position of the definitive cup was compared to that of the trial cup in polyurethane foam models. With the laser points projected onto an object > 2m away, the accuracy was ±2°.

To compare the laser guided instrumentation with the conventional aerial device, the ROM of the definitive cup was assessed in Sawbones resurfaced pelvis/femur models. The pelvis orientation was rotated by ±10° about the medio-lateral axis and the superio-inferior axis to investigate the effect of the pelvis being unknowingly out of lateral-decubitus. In the worst case of pelvis position, the aerial halved the required flexion and allowed double the required extension. The laser guided instrumentation maintained the physiological range of flexion/extension regardless of pelvis position and is therefore considered an improvement on current technology and a viable alternative to computer navigation.

Charcot arthropathy is a non-infective destructive process manifesting as dislocation, periarticular fracture or a combination of both, in patients with peripheral neuropathy

The classification and staging of charcot arthropathy assists us in decision making and appropriate management of these patients. Clinical presentation and diagnosis will be discussed as well as management techniques for the different stages of arthropathy. Neuropathic ulcer management, including new ideas, will be briefly covered.

Variability in femoral head preparation and high cement pressures may be associated with failure to seat femoral components during hip resurfacing. Furthermore, excessive pressures may lead to over penetration of bone by cement with resulting necrosis of the underlying bone. We designed an experimental model to test the hypothesis that partial-length pressure-relief slots made longitudinally in the proximal bone of the femoral head, without extending to the head neck junction, would allow controlled leakage of cement during initial insertion of a femoral head resurfacing component, but would then become sealed during final insertion to prevent excessive loss of cement while still allowing accurate seating of the component.

Thirty-one resurfacing femoral components were cemented onto foam femoral head models. The clearance between foam model and implant was measured to determine the minimum space available for cement. Eleven components were inserted using hand pressure alone, 20 were hammered. Pressure relief slots were prepared in 10 femoral heads. The slots, 4mm deep grooves, were made in the proximal bone only, without extending to the head-neck junction. Cement pressure inside the component was measured during insertion. Implants were sectioned after implantation in order to determine whether they had been fully seated or not. The clinical relevance of the measures taken was tested by measuring the diameter of prepared femoral heads during 20 hip resurfacing operations in order to determine the extent of variability in intra-operative femoral head preparation.

Mean intraoperative clearance between bone and implant was −0.19mm (0.11 to −0.93mm). Mean clearance between foam model and implant was −0.30mm (0.35 to −0.94mm). Full seating was obtained in 22/31 components. Of those not fully seated, all had clearance less than −0.74mm. Full seating with a clearance of less than −0.35mm was only possible when pressure relief slots had been made in the femur. The use of a pressure relief slot longer than half the femoral head length allowed full seating in 9/9 cases, compared to 13/22 without. Cement pressure obtained with a hand pressure technique was less than half that observed with hammering (20.8vs56.0psi, p=0.0009) but was not associated with failure to seat the implant if a slot was used.

Variability of the actual diameter of the femoral head prepared may be associated with difficulty in fully seating resurfacing components. The same degree of variability in the space available for cement was observed in both intra-operative and test specimens. The use of a pressure-relief slot allows full seating of resurfacing implants with hand pressure alone, thereby halving cement pressure, in an experimental model, even when clearance between implant and bone is less than optimal.

The clearance between the femoral head and the acetabular cup can significantly affect the lubrication, the wear and the lifetime of metal on metal (MOM) hip joints. The objective of this study was to compare the frictional behaviour of MOM joints with different clearance.

Two CoCrMo MOM 50mm diameter hip joints, with a small diametral clearance of 17 microns and a big diametral clearance of 212 microns, were used in this study. The friction measurement was carried on the wear patches of MOM bearings during a long-term wear simulator test. A dynamic trapezoidal-form loading cycle was applied to the femoral head with a minimum load of 100N during the swing phase and a maximum load of 2000N throughout the stance phase. A simple harmonic motion of amplitude +/−24 degree was applied to the femoral head in the flexion-extension plane with a frequency of 1 Hz. The friction torque was measured at 0, 0.8, 1.3, 1.9, 4 and 5.5 million cycles using 6 different viscosities of 25% new born calf serum.

The results show that the friction factors (f) of small clearance were generally higher than those of big clearance and this difference became wider with the progress of wear. The lower f of big clearance, especially in the lower range of Sommerfeld number (z) after 5.5 million cycles, is significant and will affect the ultimate performance of prostheses as this range has closer rheological properties to synovial fluid and represents long term wear conditions. At the same time, the friction factors were always higher every time when measured from high z to low z, although this difference became slightly smaller with the progress of wear, which indicates that there is still direct contact between the bearings. The lower friction factor when increasing z, is due to the wear and bedding-in with the progress of the measurement. It is concluded that large clearance has lower friction factor than small clearance, and full fluid film lubrication is unlikely to have developed between the MOM bearings in this study, even with a small clearance and high viscosity.

We previously compared the component alignment in total knee replacement using a computer-navigated technique with a conventional jig-based method. We randomly allocated 71 patients to undergo either computer-navigated or conventional replacement. An improved alignment was seen in the computer-navigated group.

The patients were then followed up post-operatively for two years, using the Knee Society score, the Short Form-36 health survey, the Western Ontario and McMaster Universities osteoarthritis index, the Bartlett Patellar pain questionnaire and the Oxford knee score, to assess functional outcome.

At two years post-operatively 60 patients were available for assessment, 30 in each group and 62 patients completed a postal survey. No patient in either group had undergone revision. All variables were analysed for differences between the groups either by Student’s t-test or the Mann-Whitney U test. Differences between the two groups did not reach significance for any of the outcome measures at any time point. At two years postoperatively, the frequency of mild to severe anterior pain was not significantly different (p = 0.818), varying between 44% (14) for the computer-navigated group, and 47% (14) for the conventionally-replaced group. The Bartlett Patellar score and the Oxford knee score were also not significantly different (t-test p = 0.161 and p = 0.607, respectively).

The clinical outcome of the patients with a computer-navigated knee replacement appears to be no different to that of a more conventional jig-based technique at two years post-operatively, despite the better alignment achieved with computer-navigated surgery.

The use of navigation systems to aid in the performance of total knee replacement has become an accepted method of treatment. Previous studies have shown that by using computer aided navigation the components can be implanted with more reproducible accuracy.

We present the results of a prospective randomised trial, with ethical committee approval that was performed to compare the use of a new, two-pin system with the original three-pin system to fix the tracker to bone. There were 37 patients in the two-pin group and 31 patients in the three-pin group. Pre-operative demographic data was similar. Patients were assessed pre and post operatively clinically using the Knee Society Score, WOMAC and SF36. Radiographic assessment was performed using “The Perth CT Protocol.”

At one year there was no significant difference clinically between either group. Radiographic assessment showed no significant difference in the results of all the prosthesis variables as measured by the Perth CT Protocol, except in the femoral prosthesis absolute varus/ valgus position, with the two-pin group being more accurate. The upgraded tracker fixing system in the computer navigation system allows as accurate implantation as the earlier system with less patient morbidity.

During conventional hip arthroplasties, the diseased femur is rigidified using a metallic stem. The insertion of the stem induces a change in the stress distribution in the surrounding femur, and the bone remodels; this stress distribution is a direct result of the stem stiffness characteristics. Healthy healing of the femur requires that the bone be loaded as naturally as possible. If the bone is not loaded appropriately, it can resorb which may result in stem loosening and revision. Although current rigid metallic femoral stems are very successful, a poor stress distribution may become a critical problem for younger patients as the stem/femoral bone construct will be subjected to higher loads for longer times, and since remodelling is faster, loosening can occur earlier. Reduced stiffness stems have therefore been investigated, but early failures have been reported due to increased movements, poor initial stability and the low proximal stiffness of the stem. A novel biocompatible carbon fibre reinforced plastic (CFRP) stem has been developed in light of these past experiences1. Using a series of analytical models and experimental validation tests1, the fibre type and architecture have been tailored along and across the stem to achieve healthy bone remodelling and proximal strength of the construct. In addition, a biocompatible hydroxyapatite coating was specifically designed to enhance interface strength and stability2. The present study describes the mechanical behaviour of this novel stem with particular emphasis on the stem/bone interface. 4 static and 29 fatigue tests were performed according to ISO7206; these tests were complemented by acoustic emission monitoring to identify failure mechanisms3. A stress versus number of cycles to failure (SN) curve was obtained to describe the fatigue behaviour (i) under constant amplitude cycling at various load levels and (ii) incorporating rest periods and overloads. In addition, a mechanical test was designed to characterise the motions between the bone and the stem during sinusoidal fatigue loading (5000 cycles, 0.2–2kN, 1Hz). Two linear variable differential transformers measured the vertical and horizontal displacements at the stem/ bone interface in the proximal region. 3 tests were performed on CFRP stems and 3 on a metallic stem. The CFRP stem exceeded the standard requirements. The SN curve showed good repeatability across the loading spectrum. The inclusion of overloads/static loads during fatigue had a beneficial effect on the stem endurance. This is attributed to the development of microcracks, which dissipate the load, and to creep of the resin. The amplitude of recoverable motion observed at the interface during each load cycle was similar for both types of stem (20mm and 4mm in the horizontal and vertical directions respectively) and remained below the recommended limit4. Composite materials offer high design flexibility. This has been exploited in the development of a compliant, mechanically tailored biocompatible hip stem for femoral reconstruction, and could provide an answer to hip replacement for younger, more active patients.

The concept of a congruent and incongruent joint will be introduced and the results of various distal osteotomies will be presented. The differential diagnosis of pain around the 1st metatarsophalangeal joint will also be discussed.

Although not exclusively a complication of distal osteotomies, the correction of acquired hallux varus will also be presented.

We investigated the blood supply of the common peroneal nerve. Dissection of 19 lower limbs, including six with intra-vascular injection of latex, allowed gross and microscopic measurements to be made of the blood supply of the common peroneal nerve in the popliteal fossa. This showed that a long segment of the nerve in the vicinity of the fibular neck contained only a few intraneural vessels of fine calibre. By contrast, the tibial nerve received an abundant supply from a constant series of vessels arising directly from the popliteal and posterior tibial arteries.

The susceptibility of the common peroneal nerve to injury from a variety of causes and its lack of response to operative treatment may be explained by the tenuous nature of its intrinsic blood supply.

Aim

To determine the prevalence and distribution of pain in patients with Charcot-Marie-Tooth disease and the effects of surgery on this pain.

Methods

Members of the Charcot -Marie -Tooth International support group were sent a pain questionnaire. Data about the site, nature, frequency, severity of pain, pain triggers, methods of pain relief and the response to surgery were collected.

Results

There were 399 respondents (233 women and 166 men). The most frequently reported sites of pain were the legs (79%) and feet (77%). Ankle pain was reported by 57%. Walking and exercise were the most frequent pain triggers. Rest was the most common method of modifying pain (60 % of respondents). 32 % found analgesics effective and 39% used heat to relive their pain. The most common sites for surgery were the foot (36%) and ankle (26%). In 43% of patients undergoing foot surgery and 54% of patients undergoing ankle surgery, pain had been increased or introduced following surgery.

Conclusions

Patients with Charcot-Marie-Tooth disease experience significant inherent, and probably neuropathic, pain in addition to pain from mechanical causes. Surgery is unlikely to improve or eliminate pain in these patients. It may introduce pain in some. Surgery should be confined to the treatment of structural problems, as it is often ineffective at relieving pain.

We report the results of seventy-six Harris Galante Porous Cups (HGP 1) in sixty-three patients treated by Total Hip Arthroplasty (THA) with a diagnosis of avascular necrosis (AVN) of the femur (grade III and IV). The cups were inserted between 1986 and 1994 and followed prospectively. Seventy hips with a follow up of more than five years (mean 7.6 years) were reviewed.

At last review the mean Harris Hip Score was 94 (standard deviation (& dcl001;) .8), preoperatively the mean had been 29 (& dcl001;14.7). Radiographically there was no evidence of acetabular migration. The revision rate of the femoral prosthesis was 8.6%, however only three stems (4.3%) were revised for loosening the rest being revised to allow down sizing of the femoral head. The revision rate for the acetabular prosthesis was 7.1%, (five cups). At the time of revision none of the cups were clinically loose and only required the liner to be changed. The complication rate was low with no deep infections or dislocations and only nine hips, (11.8%) with grade III heterotopic ossification. Survival analysis for both stem and cup at 8 years is 96.3% (confidence interval 91 – 100%), with a worst-case survival of 93.6%, (C.I 87.4 – 99.9%)

Previous studies of patients undergoing cemented THA for the treatment of advanced AVN have reported a high incidence of component loosening. This study shows good medium term results using the Harris Galante Porous cup for acetabular reconstruction with cemented femoral components for the treatment of this difficult problem.

This study assesses the clinical performance of the Souter-Strathclyde elbow arthroplasty with a standardised index and long term survivorship analysis.

We undertook assessment of 68 primary Souter-Strathclyde total elbow replacements. Of 53 patients assessed with pre-operative Souter-Strathclyde charts, nine died and one was lost to follow-up, 43 had radiographic and telephone review, and 38 (88%) had clinical examination according to the Mayo Elbow Performance Index.

Survival of the 43 elbows was to a mean of 72 months (range: eight to 187 months) with improvement in pain, motion, stability and function. Eight of 10 elbows in deceased patients had satisfactory scores at the last assessment. Ulnar neuropraxia occurred in eight elbows (12%), persistent sensory deficit in two (3%) and motor deficit in one. Two triceps abscesses required local skin flap cover. Revision was undertaken in 14 elbows (20%) for instability (six) bony injury (three), loosening (three) and intraoperative problems (two).

The survivorship at 13 years was 74% with 62 (91%) of all elbows achieving a satisfactory Mayo score.

The production of particulate wear debris is a recognised complication of joint arthroplasty, but interest has concentrated on local tissue reactions and a possible association with implant loosening. The fate of wear products in the body remains unknown, although some of the metals used in the construction of orthopaedic implants are known to have toxic and oncogenic properties. We report histological and electron-microscopic evidence from two cases which shows that metallic debris can be identified in the lymphoreticular tissues of the body distant from the hip some years after joint replacement. The increase in the use of total arthroplasty in younger patients, the development of new alloys and the use of porous coatings must raise concern for the long-term effects of the accumulation of wear debris in the body.

In fifty-six patients with ankylosing spondylitis three types of arthroplasty had been performed in ninety-nine hips. Forty-one of the patients were men and fifteen were women, their average age at operation being forty-two years. Primary pseudarthrosis produced well-satisfied patients, but only a fair result in five hips, whereas cup arthroplasty resulted in a poor outcome for eight hips, all of which needed revision. Total replacement of eighty-six hips, however, led to 73 per cent being graded as good or excellent up to ten years later. The main complications were deep infection of five hips, para-articular ossification around nine hips (six leading to bony ankylosis), and fibrous ankylosis of six hips.

The results of excision of the head of the radius in forty-four elbows affected by rheumatoid arthritis are presented. Relief of pain was obtained in 90 per cent and an increase in the range of flexion and extension was seen in 70 per cent. Involvement of the humero-ulnar joint seen radiologically is no contra-indication to the operation; simple excision of the radial head often gives gratifying results; In our experience the relief of pain and increased range of movement have greatly reduced the need for total replacement arthroplasty.