Background. Treating fractures is expensive and includes a long post-operative care. Intra-articular fractures are often treated with open surgery that require massive soft tissue incisions, long healing time and are often accompanied by deep wound infections. Minimally invasive surgery (MIS) is an alternative to this but when performed by surgeons and supported by X-rays does not achieve the required accuracy of surgical treatment. Methods. Functional and non-functional requirements of the system were established by conducting interviews with orthopaedic surgeons and attending fracture surgeries at Bristol Royal Infirmary to gain first-hand experience of the complexities involved. A robot-assisted fracture system (RAFS) has been designed and built for a distal femur fracture but can generally serve as a platform for other fracture types. Results. The RAFS system has been tested in BRL and the individual robots can achieve the required level of reduction positional accuracy (less than 1mm translational and 5 degrees of rotational accuracy). The system can simultaneously move two fragments. The positioning tests have been made on Sawbones. Conclusions. The proposed approach is providing an optimal solution by merging the fracture reduction knowledge of the orthopaedic surgeon and the robotic system's precision in 3D. Level of Evidence. The current level of evidence is limited and based on the Sawbones testing. Acknowledgement. This is a summary of independent research funded by the NIHR's i4i Programme. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health

Abstract. Introduction. Osteoarthritis (OA) affects more than four million people in the UK alone. Bone marrow lesions (BMLs) are a common feature of subchondral bone pathology in OA. Both bone volume fraction and mineral density within the BML are abnormal. The aim of this study was to investigate the effect of a potential treatment (bone augmentation) for BMLs on the knee joint mechanics in cases with healthy and fully degenerated cartilage, using finite element (FE) models of the joint to study the effect of BML size. Methods. FE models of a human tibiofemoral joint were created based on models from the Open Knee project (simtk.org). Following initial mesh convergence studies, each model was manipulated in ScanIP (Synopsys-Simpleware, UK) to incorporate a BML 2mm below the surface of the tibial contact region. Models representing extreme cases (healthy cartilage, no cartilage; BML region as an empty cavity or filled with bone substitution material (200GPa)) were generated, each with different sizes of BML. Models were tested under a representative physiological load of 2kN. Results. In the absence of cartilage, the stress distribution through the bone was more localized with higher peaks in comparison to models with cartilage. In models with cartilage, BML cavity led to changes in the stress distribution through the tibia, with increasing BML size leading to higher stresses. When the BML region was represented by the substitution material very little difference was seen in comparison to models with no defect at all. Conclusions. The results of this study illustrate how the cartilage and bone behaviour in the tibiofemoral joint are linked, and that augmentation of a BML with a bone substitute has the potential to reduce adverse loading of the surrounding bone. Funders. EPSRC, NIHR. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

Background. Assessment of functional outcome after total hip arthroplasty (THA) often involves subjective patient-reported outcome measures (PROMs) whereas analysis of gait allows more objective assessment. The aims of the study were to compare longitudinal changes of WOMAC function score and ambulatory gait analysis after THA, between patients with low and high self-reported levels of physical function. Methods. Patients undergoing primary THA (n=36; m/f=18/18; mean age=63.9; SD=9.8yrs; BMI=26.3 SD=3.5) were divided in a high and low function group, on their preoperative WOMAC function score. Patients were prospectively measured preoperatively and 3 and 12 months postoperatively. WOMAC function scores 0–100) were compared to inertial sensor based ambulatory gait analysis. Results. WOMAC function scores significantly improved in both low and high groups at 3 months postoperatively whereas gait parameters only improved in with a low pre-operative function. Between 3 and 12 months postoperatively, function scores had not significantly further improved whereas several gait parameters significantly improved in the low function group. WOMAC function scores parameters were only moderately correlated (Spearman's r = 0.33–0.51). Discussion. In routine longitudinal assessment of physical function following THA, ambulatory gait analysis can be supplementary to WOMAC. As gait significantly improved during the first 3 months and following 9 months after THA in patients with a low preoperative level of physical function only, assessment of more demanding tasks than gait may be more sensitive to capture functional improvement in patients with high preoperative function. Acknowledgements. This article presents independent research funded by the National Institute for Health Research (NIHR) under its Programme Grants for Applied Research programme (RP-PG-0407-10070). The views expressed in this article are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health. The research team acknowledges the support of the NIHR, through the Comprehensive Clinical Research Network

Background. Total hip replacement (THR) and total knee replacement (TKR) are usually effective at relieving pain; however, 7–23% of patients experience chronic post-surgical pain. These trials aimed to investigate the effect of local anaesthetic wound infiltration on pain severity at 12 months after primary THR or TKR for osteoarthritis. Methods. Between November 2009 and February 2012, 322 patients listed for THR and 316 listed for TKR were recruited into a single-centre double-blind randomised controlled trial. Participants were randomly assigned (1:1) to receive local anaesthetic infiltration and standard care or standard care alone. Participants and outcomes assessors were masked to group allocation. The primary outcome was pain severity on the WOMAC Pain scale at 12 months post-surgery. Analyses were conducted using intention-to-treat and per-protocol approaches. Ethics approval was obtained from Southampton and South West Hampshire Research Ethics Committee. Results. In the hip trial, patients in the intervention group had significantly less pain at 12 months post-operative than patients in the standard care group (differences in means 4.74; 95% CI 0.95, 8.54; p=0.015), although the difference was not clinically significant. Post-hoc analysis found that patients in the intervention group were more likely to have none to moderate pain than severe pain at 12 months than those in the standard care group (odds ratio 10.19; 95% CI 2.10, 49.55; p=0.004). In the knee trial, there was no strong evidence that the intervention influenced pain severity at 12 months post-operative (difference in means 3.83; 95% CI −0.83, 8.49; p=0.107). Conclusions. In conclusion, routine use of infiltration could be beneficial in improving long-term pain relief for some patients after THR. Level of evidence. Randomised controlled trial. Funding. This article presents independent research funded by the National Institute for Health Research (NIHR) in England under its Programme Grants for Applied Research programme (RP-PG-0407-10070). The views expressed in this article are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health. The research team acknowledge the support of the NIHR, through the Comprehensive Clinical Research Network

Background. Prosthetic implants used in primary total hip replacements have a range of bearing surface combinations (metal-on-polyethylene, ceramic-on-polyethylene, ceramic-on-ceramic, metal-on-metal); head sizes (small <36mm, large 36mm+); and fixation techniques (cemented, uncemented, hybrid, reverse hybrid), which influence prosthesis survival, patient quality of life, and healthcare costs. This study compared the lifetime cost-effectiveness of implants to determine the optimal choice for patients of different age and gender profiles. Methods. In an economic decision Markov model, the probability that patients required one or more revision surgeries was estimated from analyses of UK and Swedish hip joint registries, for males and females aged <55, 55–64, 65–74, 75–84, and 85+ years. Implant and healthcare costs were estimated from hospital procurement prices, national tariffs, and the literature. Quality-adjusted life years were calculated using utility estimates, taken from Patient-Reported Outcome Measures data for hip procedures in the UK. Results. Optimal choices varied between traditionally used cemented metal-on-polyethylene and cemented ceramic-on-polyethylene implants. Small head cemented ceramic-on-polyethylene implants were optimal for males and females aged under 65. The optimal choice for adults aged 65 and older was small head cemented metal-on-polyethylene implants. Conclusions. The older the patient, the higher the probability that small head cemented metal-on-polyethylene implants are optimal. Small head cemented ceramic-on-polyethelyne implants are optimal for adults aged under 65. Our findings can influence NICE guidance, clinical practice, and commissioning of services. Funding. NIHR Research for Patient Benefit programme PB-PG-0613-31032

Background. The Arthroplasty Pain Experience (APEX) studies are two randomised controlled trials in primary total hip (THR) and knee replacement (TKR) at a large UK orthopaedics centre. APEX investigated the effect of local anaesthetic wound infiltration (LAI), administered before wound closure, in addition to standard analgesia, on pain severity at 12 months. This abstract reports results of the within-trial economic evaluations. Methods. Cost-effectiveness was assessed from the health and social care payer perspective in relation to quality adjusted life years (QALYs). Resource use was collected from hospital records and patient-completed postal questionnaires, and valued using unit cost estimates from local NHS Trust and national tariffs. Missing data were imputed using chained equations. Costs and outcomes were compared per trial arm and plotted in cost-effectiveness planes. The economic results were bootstrapped incremental net monetary benefit statistics (INMB) and cost-effectiveness acceptability curves. One-way deterministic sensitivity analyses explored any methodological uncertainty. Results. In both trials, LAI was cost-saving and more effective than standard care. Using the £20,000 per QALY threshold, in THR, the INMB was £1,125 (95%BCI, £183 to £2,067) and the probability of being cost-effective was over 98%. In TKR, the INMB was £264 (95%BCI, −£710 to £1,238), with only 62% probability of being cost-effective. Considering an NHS perspective only, LAI was no longer dominant in THR, but still highly cost-effective, with an INMB of £961 (95%BCI, £50 to £1,873). Conclusions. Administering LAI is a cost-effective treatment option in THR and TKR surgeries. The evidence is stronger for THR, because of larger QALY gain. In TKR, there is more uncertainty around the economic result, and smaller QALY gains, but results point to LAI being cheaper than standard analgesia, which includes a femoral nerve block. Trial Registration. ISRCTN96095682, 29/04/2010. Funding. NIHR Programme Grant for Applied Research RP-PG-0407-10070

Background. Metal-on-metal (MoM) hip arthroplasty has been associated with adverse reactions including pseudotumours, and osteolysis. Tissues surrounding failed MoM hip implants are often infiltrated by inflammatory cells such as monocytes and neutrophils. The mechanisms by which these cells are recruited to the tissues remain unclear. Cobalt from MoM implants activates Toll-like receptor 4 (TLR4), an immune cell surface receptor usually responsible for recognition of bacteria and prevention of sepsis. Activation by bacteria leads to secretion of pro-inflammatory cytokines which guide other immune cells to the site of inflammation. The effect of cobalt on this response is unknown and therefore this study aims to determine the effect of cobalt-mediated TLR4 activation on the migration of inflammatory cells. Methods. A human macrophage cell line (MonoMac 6) was stimulated with a physiologically-relevant range of cobalt ions for 24h with or without pre-treatment with a TLR4 antagonist. Conditioned media was collected and used in a trans-well migration assay to determine its effect on migration of primary monocytes and neutrophils isolated from whole human blood. Migrated cells were stained with haematoxylin and counted at ×40 magnification. Results. Conditioned media from cobalt-treated macrophages caused elevated monocyte and neutrophil migration across all concentrations. Pre-treatment of MonoMac 6 cells with a TLR4 antagonist significantly decreased the response. This suggests that the cytokine profile produced in response to cobalt-mediated TLR4 activation is pro-migratory for immune cells. Conclusions. Cobalt activation of TLR4 leads to secretion of inflammatory cytokines that attract monocytes and neutrophils. This work highlights a potential mechanism by which cobalt ions from failed MoM joints could be involved in inflammatory cell recruitment to the surrounding tissues. The TLR4 signalling pathway represents an exciting area for further investigation as a therapeutic target in the prevention of adverse reactions to cobalt ions. Disclosure. This work is funded by DePuy Synthes Ltd and the Newcastle NIHR Biomedical Research Centre

Background. In the UK, over 160,000 total joint replacements are performed annually. About 1% of patients subsequently develop a deep bacterial infection and, if untreated, this can result in severe pain, disability, and death. Costs to the NHS are substantial. The INFORM (Infection Orthopaedic Management) programme aims to address gaps in knowledge relating to treatment of deep prosthetic joint infection through six work packages. The programme is supported by a patient forum and patient-partners working on oversight groups. Methods. Literature reviews and meta-analysis of individual patient data from cohort studies of patients treated for prosthetic hip infection. Analysis of the National Joint Registry to observe trends in infection rates, and identify risk markers for infection and effective treatments. Qualitative interviews with patients and health professionals exploring the impact of infection and its treatment. A multicentre randomised controlled trial to compare patient-centred outcomes after one- or two-stage revision for prosthetic hip infection. An economic evaluation to assess cost-effectiveness of treatments. A survey of patients to explore individuals’ preferences for treatments. Results. Individual patient data has been provided by UK and international centres. Data on over 1.4 million procedures is available from the National Joint Registry. Interviews conducted with 19 patients with prosthetic hip infection and 12 treating surgeons. Information has advised randomised controlled trial methodology. Seven major UK centres recruiting patients to the INFORM randomised controlled trial. Methods for assessment of costs from a health service and societal perspective developed for the randomised controlled trial. Qualitative studies have contributed to the design of a discrete choice questionnaire. Conclusions. Findings from INFORM will establish how patient care and outcomes can be optimised after prosthetic joint infection. Guidance on best clinical practice will be developed. Level of evidence 1–3. Funding statement This abstract presents independent research funded by the National Institute for Health Research (NIHR) under its Programme Grants for Applied Research scheme (grant number: RP-PG-1210-12005). The views expressed in this abstract are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health

Background. The two-stage revision strategy has been claimed as being the “gold standard” for treating prosthetic joint infection. The one-stage revision strategy remains an attractive alternative option, however, its effectiveness in comparison to the two-stage strategy remains uncertain. A systematic review and meta-analysis was conducted to compare the effectiveness of one- and two-stage revision strategies to prevent re-infection after prosthetic hip infection. Methods. Cohort studies (prospective or retrospective) conducted in unselected patients with infection treated exclusively by one- or two-stage revision and reporting re-infection outcomes within two years of revision were retrieved from MEDLINE, EMBASE, Web of Science, Cochrane databases, manual search of bibliographies to March 2015, and email contact with investigators. Data were extracted by two independent investigators and a consensus was reached with involvement of a third. Rates of re-infection were aggregated using random-effect models after arcsine transformation, and were grouped by study and population level characteristics. Results. In 38 one-stage studies, the rate (95% confidence intervals) of re-infection was 8.2% (6.0–10.8). The corresponding re-infection rate for 60 two-stage studies was 7.9% (6.2–9.7). Re-infection rates remained generally similar when grouped by several study and population level characteristics. There was no evidence of publication bias among contributing studies. Conclusion. Among unselected populations, evidence from aggregate published data suggest similar re-infection rates after one- or two-stage revision. More detailed analyses under a broader range of circumstances and exploration of other sources of heterogeneity will require collaborative pooling of individual participant data, which is ongoing within our Global Infection Orthopaedic Management (INFORM) collaboration. Level of evidence. Level 2a - Systematic reviews of cohort studies. Funding statement. This abstract presents independent research funded by the National Institute for Health Research (NIHR) under its Programme Grants for Applied Research scheme (grant number: RP-PG-1210-12005). The views expressed in this abstract are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health

Background. Around 1% of patients who have hip replacement have deep prosthetic joint infection afterwards. Infection is treated with antibiotics and revision surgery. We aimed to characterise the impact of deep joint infection and its treatment, to identify treatment preferences, and to describe surgeons' treatment decisions. Methods. In a qualitative study in the UK we interviewed 19 patients who had infection after hip replacement and 12 orthopaedic surgeons specialising in infection. Face-to-face interviews with patients explored experience of infection, treatment and recovery. Interviews with surgeons explored treatment decisions. With consent, interviews were audio-recorded, transcribed and anonymised. Once imported into QSR NVivo software, data were analysed using constant comparison. Results. Patients with deep joint infection described mobility loss, pain, loss of valued activities, changes to home environments/moving into care, negative impact on personal relationships and financial strain. Physical and psychological trauma was associated with revision surgery and antibiotic treatment. Patients had strong preferences for treatment options, emphasising impact of surgery, side effects of antibiotics and duration of treatment as key considerations. Although eradication of infection was important, patients felt that reducing impact of treatment was high priority and identified a need for more support. Surgeons' treatment decisions focused on patient characteristics and nature of infection to prioritise eradication of infection. During patients' recovery surgeons' were concerned about possible return of infection and patients' mobility and function. Conclusion. Infection after joint replacement causes physical and psychological trauma. Balancing patients' preferences for reducing impact of treatment with surgeons' emphasis on eradication of infection should be an important consideration in care. There is also need to develop new interventions to support patients with infection. Level of evidence. Level 3 – Qualitative Research. Funding statement. This paper presents independent research funded by the National Institute for Health Research (NIHR) under its Programme Grants for Applied Research scheme (grant number: RP-PG-1210-12005). The views expressed in this publication are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health. Ethics. This study has been given a favourable opinion for conduct in the NHS by the National Research Ethics Service Committee South West – Exeter 14/SW/0072

Introduction. The STarT Back trial demonstrated that targeting back pain treatment according to patient prognosis (low, medium or high-risk subgroups) is effective. However, the mechanisms leading to these improved treatment outcomes remain unknown. This study aimed to identify which psychological variables included in the study were mediating treatment outcome for all patients and within the low, medium and high-risk subgroups. Methods. Secondary analysis was conducted on 466 patients randomised to the active treatment arm with 4-month follow-up available. Psychological variables included depression (HADs), fear (TSK), catastrophising (PCS), bothersomeness and illness perception constructs (IPQ brief) e.g. personal control. Treatment outcome was characterised using change in disability score (RMDQ) at 4-months. Residualised change scores were calculated for each variable and Pearson's correlations were calculated overall and at the subgroup level to determine potential mediating variables for disability improvement. Results. Overall, correlations with RMDQ change were .62 for change in bothersomeness, .56 for change in catastrophising, .51 for change in fear, .48 for change in anxiety, .58 for change in depression, −.32 for change in personal control and .40 for change in symptom identity. The strength of correlation generally increased from low to high-risk subgroups, e.g. bothersomeness (low=.54, high=.70). However, the predominant variables mediating treatment outcome were common across risk-groups. Conclusion. The psychological variables which were highly correlated with improvements in disability were bothersomeness, depression and catastrophising. This finding was consistent across low, medium and high-risk subgroups. This study is ongoing and further mediation analysis using structural equation modelling is in progress. Conflicts of Interest. None. Source of Funding. NIHR Spinal Pain Programme grant

Objectives

To explore whether orthopaedic surgeons have adopted the Proximal Fracture of the Humerus: Evaluation by Randomisation (PROFHER) trial results routinely into clinical practice.

Trauma and orthopaedics is the largest of the surgical specialties and yet attracts a disproportionately small fraction of available national and international funding for health research. With the burden of musculoskeletal disease increasing, high-quality research is required to improve the evidence base for orthopaedic practice. Using the current research landscape in the United Kingdom as an example, but also addressing the international perspective, we highlight the issues surrounding poor levels of research funding in trauma and orthopaedics and indicate avenues for improving the impact and success of surgical musculoskeletal research.

Cite this article: Bone Joint J 2014; 96-B:1578–85.

This protocol describes a pragmatic multicentre randomised controlled trial (RCT) to assess the clinical and cost effectiveness of arthroscopic and open surgery in the management of rotator cuff tears. This trial began in 2007 and was modified in 2010, with the removal of a non-operative arm due to high rates of early crossover to surgery.

Cite this article: Bone Joint Res 2014;3:155–60.

Aims

Osteoporosis and abnormal bone metabolism may prove to be significant factors influencing the outcome of arthroplasty surgery, predisposing to complications of aseptic loosening and peri-prosthetic fracture. We aimed to investigate baseline bone mineral density (BMD) and bone turnover in patients about to undergo arthroplasty of the hip and knee.