Jill Dawson

Questionnaire on the perceptions of patients about total knee replacement

We developed a 12-item questionnaire for completion by patients having total hip replacement (THR). A prospective study of 220 patients was undertaken before operation and at follow-up six months later. Each completed the new questionnaire as well as the SF36, and some the Arthritis Impact Measurement Scales (AIMS). An orthopaedic surgeon assessed the Charnley hip score. The single score derived from the questionnaire had a high internal consistency. Reproducibility was examined by test-retest reliability and was found to be satisfactory. The validity of the questionnaire was established by obtaining significant correlation in the expected direction with the Charnley scores and relevant scales of the SF36 and the AIMS. Sensitivity to change was assessed by analysing the differences between the preoperative scores and those at the follow-up. The standardised effect size for the new questionnaire compared favourably with that for the SF36 and the AIMS. The new questionnaire provides a measure of outcome for THR which is short, practical, reliable, valid and sensitive to clinically important changes.

The use of the Oxford hip and knee scores

The Oxford hip and knee scores have been extensively used since they were first described in 1996 and 1998. During this time, they have been modified and used for many different purposes. This paper describes how they should be used and seeks to clarify areas of confusion.

Comparing alternative Rasch-based methods vs raw scores in measuring change in health.

ObjectivesTo compare alternative Rasch-based approaches to the assessment of change over time through the example of an outcome measure used in total hip replacement surgery. SubjectsPreoperative data were collected on 1424 patients receiving total hip replacement surgery; 1221 (86%) were sent follow-up questionnaires 1 year after surgery. MeasuresThe 12-item Oxford Hip Score (OHS) questionnaire administered preoperatively and 1-year postoperatively. MethodsSubscales of the OHS for pain and functional impairment were examined for unidimensionality and item invariance. Two criteria were used to examine Rasch-based measurement of the 2 subscales. Advantages of Rasch measurement were examined in terms of whether it produced improved discrimination of outcomes of patients (1) undergoing different levels of complexity of surgery; and (2) reporting different retrospective judgments of the success of their surgery. Using the method of relative precision in relation to groups of patients distinguished in these 2 ways, change scores using Likert scoring methods were compared with 2 Rasch scoring methods: (1) separate analyses of the 2 time points; and (2) a common scale analysis obtained by stacking patients from the 2 time points. ResultsLess evidence for item invariance over time was found for the pain subscale. Other evidence supported treating subscales as unidimensional. Whichever Rasch scoring method was used, some gains in precision over standard Likert scoring were obtained in discriminating between groups of patients. ConclusionsThe evidence from the current study suggests that there may be some gains in sensitivity to change of outcome measures from different Rasch-based scoring approaches.

An investigation of risk factors for symptomatic osteoarthritis of the knee in women using a life course approach.

Study objective: To explore risk factors for symptomatic knee osteoarthritis (OAK) in women, which included wearing high heeled shoes. Design: Matched case-control study. Exposure information obtained by interview, included details about past footwear. Self reported weight and height data obtained representing when women left school, were aged 36–40 and were aged 51–55. Regular work activities (including periods when homemaker or carer), smoking, and hormone related data gathered using a life-grid. Setting: Interviews in participants’ homes. Cases identified from orthopaedic hospital surgical waiting list, controls identified by general practitioners (GPs) Participants: Women aged 50 to 70 years. Cases awaiting knee replacement surgery. Controls, who had no past knee surgery and no knee pain in the past three years, were matched for age and GP. Altogether 111 eligible women were interviewed (29 cases, 82 controls). Main results: Univariate analyses identified several significant associations with OAK including past knee injury, arthritis of the feet, heavy smoking, being overweight (BMI 25 or above) and various occupational activities. Virtually all measures of high heeled shoes use were associated with reduced risk of OAK, although none of these findings were statistically significant. In multivariate analysis only BMI 25 or above at age 36–40 remained significantly associated with OAK (OR 36.4, 95% CI 3.07 to 432, p=0.004), although weak evidence suggested certain occupational activities might increase risk. Weight gain in early adult life was particularly pronounced among cases. Conclusions: Being overweight before the age of 40 considerably increased the risk of subsequent symptomatic OAK in women. Wearing high heeled shoes did not.

Clinical effectiveness and cost-effectiveness of open and arthroscopic rotator cuff repair [the UK Rotator Cuff Surgery (UKUFF) randomised trial]

BACKGROUND Uncertainty exists regarding the best management of patients with degenerative tears of the rotator cuff. OBJECTIVE To evaluate the clinical effectiveness and cost-effectiveness of arthroscopic and open rotator cuff repair in patients aged ≥ 50 years with degenerative rotator cuff tendon tears. DESIGN Two parallel-group randomised controlled trial. SETTING Nineteen teaching and district general hospitals in the UK. PARTICIPANTS Patients (n = 273) aged ≥ 50 years with degenerative rotator cuff tendon tears. INTERVENTIONS Arthroscopic surgery and open rotator cuff repair, with surgeons using their usual and preferred method of arthroscopic or open repair. Follow-up was by telephone questionnaire at 2 and 8 weeks after surgery and by postal questionnaire at 8, 12 and 24 months after randomisation. MAIN OUTCOME MEASURES The Oxford Shoulder Score (OSS) at 24 months was the primary outcome measure. Magnetic resonance imaging evaluation of the shoulder was made at 12 months after surgery to assess the integrity of the repair. RESULTS The mean OSS improved from 26.3 [standard deviation (SD) 8.2] at baseline to 41.7 (SD 7.9) at 24 months for arthroscopic surgery and from 25.0 (SD 8.0) at baseline to 41.5 (SD 7.9) at 24 months for open surgery. When effect sizes are shown for the intervention, a negative sign indicates that an open procedure is favoured. For the intention-to-treat analysis, there was no statistical difference between the groups, the difference in OSS score at 24 months was -0.76 [95% confidence interval (CI) -2.75 to 1.22; p = 0.452] and the CI excluded the predetermined clinically important difference in the OSS of 3 points. There was also no statistical difference when the groups were compared per protocol (difference in OSS score -0.46, 95% CI -5.30 to 4.39; p = 0.854). The questionnaire response rate was > 86%. At 8 months, 77% of participants reported that shoulder problems were much or slightly better, and at 24 months this increased to 85%. There were no significant differences in mean cost between the arthroscopic group and the open repair group for any of the component resource-use categories, nor for the total follow-up costs at 24 months. The overall treatment cost at 2 years was £2567 (SD £176) for arthroscopic surgery and £2699 (SD £149) for open surgery, according to intention-to-treat analysis. For the per-protocol analysis there was a significant difference in total initial procedure-related costs between the arthroscopic group and the open repair group, with arthroscopic repair being more costly by £371 (95% CI £135 to £607). Total quality-adjusted life-years accrued at 24 months averaged 1.34 (SD 0.05) in the arthroscopic repair group and 1.35 (SD 0.05) in the open repair group, a non-significant difference of 0.01 (95% CI -0.11 to 0.10). The rate of re-tear was not significantly different across the randomised groups (46.4% and 38.6% for arthroscopic and open surgery, respectively). The participants with tears that were impossible to repair had the lowest OSSs, the participants with re-tears had slightly higher OSSs and the participants with healed repairs had the most improved OSSs. These findings were the same when analysed per protocol. CONCLUSION In patients aged > 50 years with a degenerative rotator cuff tear there is no difference in clinical effectiveness or cost-effectiveness between open repair and arthroscopic repair at 2 years for the primary outcome (OSS) and all other prespecified secondary outcomes. Future work should explore new methods to improve tendon healing and reduce the high rate of re-tears observed in this trial. TRIAL REGISTRATION Current Controlled Trials ISRCTN97804283. FUNDING This project was funded by the National Institute for Health Research Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 19, No. 80. See the NIHR Journals Library website for further project information.

Regular partners and risky behaviour: Why do gay men have unprotected intercourse?

Studies in both the UK and the USA continue to show that gay and bisexual men put themselves at risk of exposure to HIV through unprotected intercourse, most often with regular partners. As part of a larger study of homosexually active men, 310 men who had had unprotected anal intercourse with a man in the previous year were asked to describe the last occasion on which this had happened. The majority of men had had unprotected intercourse with a regular partner and did not perceived it as risky, although most did not know the HIV status of their partner. Regular and non-regular partners were perceived differently. Men were more likely to be emotionally involved in regular partners and to perceive unprotected penetrative sex with a regular partner as not risky. Future health education initiatives must take into account mens emotional involvement in regular partners and their perception of unprotected intercourse with such partners as not risky.

A patient-based questionnaire to assess outcomes of foot surgery: Validation in the context of surgery for hallux valgus

Background: A patient-based outcome measure with good measurement properties is urgently needed for use in clinical trials of foot surgery. Methods: We evaluated an existing foot pain and disability questionnaire (the Manchester Foot Pain and Disability Questionnaire) for its suitability as an outcome measure in the context of hallux valgus corrective surgery. Interviews with patients led to initial changes, resulting in 20 candidate questionnaire items with five response categories each. These were tested in a prospective study of 100 patients (representing 138 foot operations) undergoing hallux valgus corrective surgery. Analysis of underlying factor structure, dimensionality, internal reliability, construct validity and responsiveness of the questionnaire items in relation to (i) SF-36 general health survey and (ii) American Orthopaedic Foot & Ankle Society (AOFAS) hallux clinical scale resulted in a final 16 item questionnaire (the ‘Manchester-Oxford Foot Questionnaire’ (MOXFQ)), consisting of three domains/scales: ‘Walking/standing’ (seven items), ‘Pain’ (five items) and ‘Social interaction’ (four items) each having good measurement properties. All three domains were unidimensional. Conclusions: The new 16-item MOXFQ has good measurement properties in the context of outcomes assessment of surgery for hallux valgus. Future studies should assess the MOXFQ in the context of surgery for other foot and ankle conditions.

The problem of 'noise' in monitoring patient-based outcomes: generic, disease-specific and site-specific instruments for total hip replacement.

Objectives: To compare the performance of three types of patient-based health status instrument — generic, disease-specific and site-specific — in assessing changes resulting from total hip replacement (THR). Methods: A two-stage prospective study of patients undergoing surgery for THR involving an assessment at a pre-surgical clinic and a follow-up clinic at 6 months. 173 patients with a diagnosis of arthritis and being admitted for unilateral THR were recruited in the outpatient departments of a specialist orthopaedic hospital and peripheral clinics within Oxfordshire. Patients’ health status was assessed using the 12-item Oxford Hip Score, the Arthritis Impact Measurement Scales (AIMS) and SF-36 general health questionnaire together with their surgeons’ assessment using Charnley hip score obtained before and 6 months after surgery. Results: Effect sizes, used to compare change scores, revealed that pain and function domains changed most following THR on both the AIMS and the SF-36. 71 patients (41%) were assessed as having symptoms or problems currently affecting lower limb joints other than the hip recently replaced. Change scores were compared between these patients and all other patients who reported no current problems with other joints. The Oxford Hip Score found no significant difference between change scores for these two groups of patients while both AIMS and SF-36 physical and pain dimensions recorded significant differences of similar magnitude (physical P < 0.01, pain P < 0.05). Likely reasons for this were apparent on closer inspection of the item content of each instrument. Conclusions: Assessment of outcomes in THR is necessarily long-term. Within studies of this kind, a hip-specific instrument (Oxford Hip Score) is likely to be more able to distinguish between symptoms and functional impairment produced by the index joint, as compared with other joints and conditions, than either a disease-specific instrument (AIMS) or a generic health status measure (SF-36). This is important given the high probability of existing and subsequent co-morbidity affecting such populations of patients. This consideration is likely to be relevant to any long-term assessment programme following treatment for a condition which threatens bilateral expression over time.

Meaningful changes for the Oxford hip and knee scores after joint replacement surgery.

Objectives To present estimates of clinically meaningful or minimal important changes for the Oxford Hip Score (OHS) and the Oxford Knee Score (OKS) after joint replacement surgery. Study Design and Setting Secondary data analysis of the NHS patient-reported outcome measures data set that included 82,415 patients listed for hip replacement surgery and 94,015 patients listed for knee replacement surgery was performed. Results Anchor-based methods revealed that meaningful change indices at the group level [minimal important change (MIC)], for example in cohort studies, were ∼11 points for the OHS and ∼9 points for the OKS. For assessment of individual patients, receiver operating characteristic analysis produced MICs of 8 and 7 points for OHS and OKS, respectively. Additionally, the between group minimal important difference (MID), which allows the estimation of a clinically relevant difference in change scores from baseline when comparing two groups, that is, for clinical trials, was estimated to be ∼5 points for both the OKS and the OHS. The distribution-based minimal detectable change (MDC90) estimates for the OKS and OHS were 4 and 5 points, respectively. Conclusion This study has produced and discussed estimates of minimal important change/difference for the OKS/OHS. These estimates should be used in the power calculations and the interpretation of studies using the OKS and OHS. The MDC90 (∼4 points OKS and ∼5 points OHS) represents the smallest possible detectable change for each of these instruments, thus indicating that any lower value would fall within measurement error.

Assessing patients for joint replacement: Can pre-operative Oxford hip and knee scores be used to predict patient satisfaction following joint replacement surgery and to guide patient selection?

We obtained pre-operative and six-month post-operative Oxford hip (OHS) and knee scores (OKS) for 1523 patients who underwent total hip replacement and 1784 patients who underwent total knee replacement. They all also completed a six-month satisfaction question. Scatter plots showed no relationship between pre-operative Oxford scores and six-month satisfaction scores. Spearmans rank correlation coefficients were -0.04 (95% confidence interval (CI) -0.09 to 0.01) between OHS and satisfaction and 0.04 (95% CI -0.01 to 0.08) between OKS and satisfaction. A receiver operating characteristic (ROC) curve analysis was used to identify a cut-off point for the pre-operative OHS/OKS that identifies whether or not a patient is satisfied with surgery. We obtained an area under the ROC curve of 0.51 (95% CI 0.45 to 0.56) for hip replacement and 0.56 (95% CI 0.51 to 0.60) for knee replacement, indicating that pre-operative Oxford scores have no predictive accuracy in distinguishing satisfied from dissatisfied patients. In the NHS widespread attempts are being made to use patient-reported outcome measures (PROMs) data for the purpose of prioritising patients for surgery. Oxford hip and knee scores have no predictive accuracy in relation to post-operative patient satisfaction. This evidence does not support their current use in prioritising access to care.