Patient expectations regarding total knee arthroplasty: differences among the United States, United Kingdom, and Australia.

BACKGROUND: Total knee arthroplasty is an effective treatment for severe osteoarthritis of the knee. Our aim was to determine whether patients from the United Kingdom, United States, and Australia have different preoperative expectations regarding total knee arthroplasty and whether these expectations have an impact on outcomes and patient satisfaction. METHODS: Patients from the United Kingdom, the United States, and Australia were recruited into a prospective observational study of primary total knee arthroplasty for the treatment of osteoarthritis. Preoperative expectations, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Short Form-36 (SF-36) scores, and demographic, socioeconomic, and follow-up data, including satisfaction with outcome, were obtained from self-administered patient questionnaires. RESULTS: A total of 598 patients with a mean age of sixty-nine years at the time of the index arthroplasty were recruited; 58% were women. The majority of patients expected to have no pain at twelve months after the surgery, and with the numbers available there was no significant difference among the countries with regard to pain expectations. Australian patients were more likely than patients in the United Kingdom or the United States to expect better function at twelve months after the surgery. With the numbers available, satisfaction scores at twelve months did not differ significantly among the countries and were not influenced by preoperative expectations. Australian patients were more likely than patients in the United Kingdom or the United States to be unwilling to undergo total knee arthroplasty again at twelve months under similar circumstances. CONCLUSIONS: Patients from different countries have different expectations regarding total knee arthroplasty, which are not fully explained by differences in sociodemographic factors, clinical characteristics, and pain and functional status. Australian patients had the highest expectations but, despite reporting similar outcomes and satisfaction following total knee arthroplasty, they were more likely not to want to have the surgery again under similar circumstances.

Predicting the outcome of total knee arthroplasty.

BACKGROUND: The relief of pain and the restoration of functional activities are the main outcomes of primary total knee arthroplasty for the treatment of osteoarthritis. This paper examines the preoperative predictors of pain and functional outcome at one and two years following total knee arthroplasty. METHODS: Patients were recruited for a prospective observational study of primary total knee arthroplasty for the treatment of osteoarthritis from centers in the United States, the United Kingdom, and Australia. Research assistants recruited the patients and collected the clinical history and physical examination data preoperatively and at three, twelve, and twenty-four months postoperatively. The Western Ontario and McMaster University Osteoarthritis Index (WOMAC), Short Form-36 (SF-36), and demographic data were obtained by self-administered patient questionnaires. RESULTS: We recruited 860 patients and obtained one-year WOMAC data on 759 patients (88%) and two-year data on 701 (82%). The mean age was seventy years, and 59% of the patients were female. Using hierarchical regression models, we found that the most significant preoperative predictors of worse scores on the pain and function domains of the WOMAC scale and on the physical functioning domain of the SF-36 at one and two years postoperatively were low preoperative scores, a higher number of comorbid conditions, and a low SF-36 mental health score. After adjusting for these predictors, we found that the functional status of the patients from the United Kingdom was significantly worse than that of the patients from the other countries and the difference was clinically important at both the one-year and two-year follow-up examination (p < 0.0005). The mean WOMAC pain scores for the three countries were not significantly different at one year, and, although they were significantly different at two years (p = 0.025), the difference was not clinically important. CONCLUSIONS: Patients who have marked functional limitation, severe pain, low mental health score, and other comorbid conditions before total knee arthroplasty are more likely to have a worse outcome at one year and two years postoperatively. After adjusting for these predictors, it was found that patients from the United Kingdom had significantly worse functional outcomes but similar pain relief compared with those from the United States and Australia.

Patient-reported outcome and survivorship after Kinemax total knee arthroplasty.

BACKGROUND: We examined the long-term survivorship and patient-reported outcomes at a minimum of ten years following primary total knee arthroplasty. We hypothesized (1) that the survival rate would be at least 90% at ten years; (2) that age, gender, body-mass index, and primary diagnosis would not affect the survival rate; and (3) that the functional status of patients would be comparable with that of an age and gender-matched normal population. METHODS: A total of 407 patients (523 knees) who had had primary total knee arthroplasty between January 1988 and April 1991 were identified. The mean age of the patients at the time of surgery was sixty-nine years, and 68% of the patients were women. At ten years, 165 patients (211 knees) had died; seven of these 211 knees had been revised before the time of death. Of the remaining 242 patients, 208 (86%) completed a questionnaire, which included the Western Ontario and McMaster University Osteoarthritis Index (WOMAC), the Short Form-36 (SF-36), and questions regarding patient satisfaction and revision surgery. In the group of patients who participated in the study, ten patients (eleven knees) had had a revision before the review. RESULTS: A total of eighteen knees were revised. Twelve knees were revised because of aseptic failure and, of these, nine were revised because of polyethylene wear. The probability of survival at ten years was 96.1% with revision for any reason as the end point (and 97.2% when only aseptic failures were considered). Because of the small number of failures, we were unable to draw conclusions about associations between failure and age, gender, diagnosis, and body-mass index. The mean WOMAC scores (and standard deviation) at the time of the evaluation were 88 +/- 17 for pain and 79 +/- 20 for function. The SF-36 scores were similar to those for an age and gender-matched normal population, with only the physical functioning score being significantly lower (p < 0.001) and with the general health score being significantly higher (p < 0.001). Patients generally were very satisfied with all aspects of the outcome. CONCLUSIONS: At ten years, the survival of the prosthesis was excellent and the majority of patients were functionally independent, had very little knee pain, and were very satisfied with the result. The health benefits of this total knee arthroplasty were maintained after a minimum duration of follow-up of ten years.

Improving the postmarket surveillance of total joint arthroplasty devices.

OBJECTIVE: To evaluate the FDA's approval process and postmarket surveillance strategies for THR devices. DESIGN: The FDA Center for Devices and Radiological Health (CDRH) 510k releasable database was used to document approved THR devices. The CDRH Medical Device Reporting data files were used to study the efficiency of the FDA's post-market surveillance system. Manufacturers were contacted to supply information regarding their implants. Medline was searched between 1966-1996 to determine the percentage of THR devices with published data on clinical outcomes. RESULTS: Between 1976 and 1996, 701 new THR devices were approved by the Substantial Equivalent (SE) route and 34 were approved on the basis of Premarket Approval PMA. The number of approvals doubled between 1991-1995 compared to 1976-1990. Seventy-four different manufacturers obtained approval to market THR devices. Only four manufacturers obtained approval via the PMA application. Under Mandatory Device Reporting all revision arthroplasties should be reported. Using data from 2 independent services for which we had US hospital discharge data in 1993 we estimate that only 3% of all revision THR were reported to the FDA. Manufacturers of hip implants failed to provide useful information. Medline search revealed only 15% of the approved THR devices had published data on outcomes. CONCLUSION: Current FDA premarket approval and postmarket surveillance strategies fail to provide information for evidence-based selection of THR devices. Recommendations are made to avert problems with device failures.

Validation of a Japanese patient-derived outcome scale for assessing total knee arthroplasty: comparison with Western Ontario and McMaster Universities osteoarthritis index (WOMAC).

We have developed a Japanese self-administered questionnaire based on an English version of the Western Ontario and McMaster Universities osteoarthritis index (WOMAC) to measure subjective function and pain status of patients who undergo a total knee arthroplasty procedure. Using multiple international cohorts, the performance of the developed Japanese scale was compared to the results of the WOMAC in the United Kingdom, United States, Canada, and Australia. The developed scale showed a comparable level of internal consistency and construct/criterion validity. The responsiveness of the scale was superior to the concurrently measured MOS Short Form 36 Physical Function scale. These results suggest that the developed scale is reliable, valid, and responsive for assessing the effectiveness of total knee arthroplasty in the Japanese context despite the cultural life style differences from Western countries.

Knee range of motion after total knee arthroplasty: how important is this as an outcome measure?

We investigated the relationship of knee range of motion (ROM) and function in a prospective, observational study of primary total knee arthroplasty (TKA). Preoperative and 12-month data were collected on 684 patients, including knee ROM, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain and function questionnaire scores, patient satisfaction, and perceived improvement in quality of life (QOL). Only modest correlations were found between knee ROM and WOMAC function (r<0.34). At 12 months we found significantly worse WOMAC function scores for patients with <95 degrees flexion compared with patients with > or =95 degrees (mean, 61.9 vs 75.0; P<.0001). In linear regression models, WOMAC pain and function scores at 12 months were both correlates of patient satisfaction and perceived improvement in QOL (standardized beta>3.5; P<.0001), but knee flexion was not. For assessment of these outcomes, WOMAC function appears to be more important than knee flexion.