D W Murray

Pain in the assessment of total knee replacement.

The results of total knee replacement (TKR) are commonly assessed by survival analysis using revision as the endpoint. We have used the assessment of pain by a patient-based questionnaire as an alternative. In one hospital, 1429 TKRs were inserted by 66 surgeons between 1987 and 1993. The survival at seven years, with revision as the endpoint, was 97.5% (CI 94 to 100). There were no significant differences between the three different types of implant used, the AGC, the IB2 and the Nuffield Knee. When the endpoint was the development of moderate pain, the survival at seven years for the AGC knee was 72% and that for the IB2 was similar. Significantly more patients (p = 0.007) with the Nuffield Knee, however, had developed moderate pain. Using revision as the endpoint, it is difficult to discriminate between the various types of TKR, but this can be achieved using pain. In this investigation 30% of the patients reported moderate pain at some stage by seven years from operation.

Rationing of total knee replacement: a cost-effectiveness analysis on a large trial data set.

Objectives Many UK primary care trusts have recently introduced eligibility criteria restricting total knee replacement (TKR) to patients with low pre-operative Oxford Knee Scores (OKS) to cut expenditure. We evaluate these criteria by assessing the cost-effectiveness of TKR compared with no knee replacement for patients with different baseline characteristics from an NHS perspective. Design The cost-effectiveness of TKR in different patient subgroups was assessed using regression analyses of patient-level data from the Knee Arthroplasty Trial, a large, pragmatic randomised trial comparing knee prostheses. Setting 34 UK hospitals. Participants 2131 osteoarthritis patients undergoing TKR. Interventions and outcome measures Costs and quality-adjusted life years (QALYs) observed in the Knee Arthroplasty Trial within 5u2005years of TKR were compared with conservative assumptions about the costs and outcomes that would have been accrued had TKR not been performed. Results On average, primary TKR and 5u2005years of subsequent care cost £7458 per patient (SD: £4058), and patients gained an average of 1.33 (SD: 1.43) QALYs. As a result, TKR cost £5623/QALY gained. Although costs and health outcomes varied with age and sex, TKR cost <£20u2008000/QALY gained for patients with American Society of Anaesthesiologists grades 1–2 who had baseline OKS <40 and for American Society of Anaesthesiologists grade 3 patients with OKS <35, even with highly conservative assumptions about costs and outcomes without TKR. Body mass index had no significant effect on costs or outcomes. Restricting TKR to patients with pre-operative OKS <27 would inappropriately deny a highly cost-effective treatment to >10u2008000 patients annually. Conclusions TKR is highly cost-effective for most current patients if the NHS is willing to pay £20u2008000–£30u2008000/QALY gained. At least 97% of TKR patients in England have more severe symptoms than the thresholds we have identified, suggesting that further rationing by OKS is probably unjustified. Trial registration number ISRCTN 45837371.

The Knee Arthroplasty Trial (KAT) design features, baseline characteristics, and two-year functional outcomes after alternative approaches to knee replacement.

BACKGROUNDnThe aim of continued development of total knee replacement systems has been the further improvement of the quality of life and increasing the duration of prosthetic survival. Our goal was to evaluate the effects of several design features, including metal backing of the tibial component, patellar resurfacing, and a mobile bearing between the tibial and femoral components, on the function and survival of the implant.nnnMETHODSnA pragmatic, multicenter, randomized, controlled trial involving 116 surgeons in thirty-four centers in the United Kingdom was performed; 2352 participants were randomly allocated to be treated with or without a metal backing of the tibial component (409), with or without patellar resurfacing (1715), and/or with or without a mobile bearing (539). Randomization to more than one comparison was allowed. The primary outcome measures were the Oxford Knee Score (OKS), Short Form-12, EuroQol-5D, and the need for additional surgery. The results up to two years postoperatively are reported.nnnRESULTSnFunctional status and quality-of-life scores were low at baseline but improved markedly across all trial groups following knee replacement (mean overall OKS, 17.98 points at baseline and 34.82 points at two years). Most of the change was observed at three months after the surgery. Six percent of the patients had additional knee surgery within two years. There was no evidence of differences in clinical, functional, or quality-of-life measures between the randomized groups at two years.nnnCONCLUSIONSnPatients have substantial improvement following total knee replacement. This is the first adequately powered randomized controlled trial, of which we are aware, in which the effects of metal backing, patellar resurfacing, and a mobile bearing were investigated. We found no evidence of an effect of these variants on the rate of early complications or on functional recovery up to two years after total knee replacement.

Dislocation of the bearing of the Oxford lateral unicompartmental arthroplasty. A radiological assessment.

When the Oxford unicompartmental meniscal bearing arthroplasty is used in the lateral compartment of the knee, 10% of the bearings dislocate. A radiological review was carried out to establish if dislocation was related to surgical technique. The postoperative radiographs of 46 lateral unicompartmental arthroplasties were analysed. Five variables which related to the position and alignment of the components were measured. Dislocations occurred in six knees. Only one of the five variables, the proximal tibial varus angle, had a statistically significant relationship to dislocation. This variable quantifies the height of the lateral joint line. The mean proximal tibial varus angle for knees the bearings of which had dislocated was 9 degrees and for those which had not it was 5 degrees. In both groups it was greater than would be expected in the normal knee (3 degrees). Our study suggests that a high proximal tibial varus angle is associated with dislocation. The surgical technique should be modified to account for this, with care being taken to avoid damage to or overdistraction of the lateral soft tissues.

Total hip replacement: indications for surgery and risk factors for failure

Total hip replacement is one of the most successful and cost effective interventions in medicine.1 2 It offers reliable relief of pain and considerable improvement in function in patients suffering with osteoarthritis or inflammatory arthritis of the hip.3-7 Currently about 50u2009000 hip replacements are performed in the United Kingdom annually while worldwide the number is over 300u2009000. Two thirds of these are performed in patients over 65 years of age.8 Ninety to ninety five per cent of patients can expect to have their total hip replacement functioning at 10 years,8 and in 85% they will still be functioning at 20 years.9 nnAlthough 85% of patients undergoing total hip replacement have a diagnosis of osteoarthritis,8 inflammatory arthritis, both seropositive and seronegative, is an important indication for total hip replacement and can offer tremendous improvements in quality of life even in the very young.10 In rheumatoid arthritis it has been estimated that the cost to the community of total hip replacement will be recuperated within an average 1.5 years because of savings made on medical and social care.2 nnQuality of life after surgery approximates that of a healthy reference population.4 Improvements in pain, energy levels, sleep, social, and sexual function are all observed.4 7 Oxygen demands on activity are decreased and walking ability improves.5 11 Most of these improvements are seen within three months of surgery.5 These gains in quality of life allow large numbers of patients to retain their independence and function more actively in society.nn### PAINnnPain is the principal indication for hip replacement and is reliably relieved as early as one week after surgery.12 Pain from an arthritic hip is classically located in the groin and buttock. Radiation into the thigh may occur and at times pain …

Impingement and loosening of the long posterior wall acetabular implant

Long posterior wall (LPW) Charnley acetabular implants are widely used as it is believed that the LPW helps to prevent dislocation. This has, however, not been proven statistically. In a preliminary study of these implants removed at revision marked erosion of the LPW was frequently seen, indicating that repetitive impingement may occur. The influence of the long posterior wall was therefore investigated mathematically. LPW and standard sockets were found to be equally likely to dislocate provided that the standard socket was anteverted 5 degrees more than the LPW socket. With simulated external rotation, LPW sockets impinge 30% earlier than standard sockets. When impingement occurs a torque is applied to the components, which increases the shear stresses at the cement-bone interface. The torques, although not large enough to dislodge the socket immediately, are repetitive and so may contribute to loosening. The LPW socket can generate twice as much torque as the standard socket and therefore is more likely to loosen.

Risks and benefits of prophylaxis against venous thromboembolism in orthopaedic surgery.

W. Gillespie, DeanDunedin School of Medicine, PO Box 913, Dunedin, New Zealand.D. Murray, MD, FRCS, FRCS (Orth), Professor of Orthopaedic SurgeryNuffield Orthopaedic Centre, Windmill Road, Headington, Oxford OX37LD, UK.P. J. Gregg, MD, FRCS, Professor of Orthopaedic SurgeryThe Medical School, University of Newcastle upon Tyne, Newcastle uponTyne NE2 4HH, UK.D. Warwick, MD, FRCS, FRCS (Orth), Consultant Orthopaedic SurgeonSouthampton University Hospitals NHS Trust, Tremona Road, South-ampton SO16 6YD, UK.Correspondence should be sent to W. Gillespie©2000 British Editorial Society of Bone and Joint Surgery0301-620X/00/410452

Patellar resurfacing in total knee replacement: five-year clinical and economic results of a large randomized controlled trial.

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The trainer, the trainee and the surgeons' assistant: clinical outcomes following total hip replacement.

BACKGROUNDnThere is conflicting evidence regarding the merits of patellar resurfacing during total knee arthroplasty, as many of the previous randomized controlled trials have not been adequately powered.nnnMETHODSnA pragmatic, multicenter, randomized controlled trial was initiated in 1999 in the United Kingdom. Within a partial factorial design, 1715 patients were randomly allocated to receive or not receive patellar resurfacing during total knee arthroplasty. The primary outcome measure was the Oxford Knee Score; secondary measures included the Short Form-12, the EuroQoL 5D, cost, cost-effectiveness, and the need for subsequent knee surgery.nnnRESULTSnThe mean Oxford Knee Score was 35 points at five years postoperatively in both groups. There was no significant difference between the groups with respect to the mean Oxford Knee Score (difference, 0.59 point; 95% confidence interval, -0.58 to 1.76 points) or any other outcome measure at five years postoperatively. The outcome was not affected by whether the patella was domed or anatomic. There was no significant difference between the two groups with respect to the prevalence of knee-related readmission, of minor or intermediate reoperation, or of subsequent patella-related surgery. The total health care cost for the primary arthroplasty, subsequent monitoring, and any revision surgery did not differ significantly between the two groups.nnnCONCLUSIONSnIn the largest randomized controlled trial of patellar resurfacing reported to date, the functional outcome, reoperation rate, and total health care cost five years after primary total knee arthroplasty were not significantly affected by the addition of patellar resurfacing to the surgical procedure.

Femoral offset is underestimated on anteroposterior radiographs of the pelvis but accurately assessed on anteroposterior radiographs of the hip

Balancing service provision and surgical training is a challenging issue that affects all healthcare systems. A multicentre prospective study of 1501 total hip replacements was undertaken to investigate whether there is an association between surgical outcome and the grade of the operating surgeon, and whether there is any difference in outcome if surgeons assistants assist with the operation, rather than orthopaedic trainees. The primary outcome measure was the change in the Oxford hip score (OHS) at five years. Secondary outcomes included the rate of revision and dislocation, operating time, and length of hospital stay. There was no significant difference in DeltaOHS or complication rates between operations undertaken by trainers and trainees, or those at which surgeons assistants and trainees were the assistant. However, there was a significant difference in the duration of surgery, with a mean reduction of 28 minutes in those in which a surgeons assistant was the assistant. This study provides evidence that total hip replacements can be performed safely and effectively by appropriately trained surgeons in training, and that there are potential benefits of using surgeons assistants in orthopaedic surgery.