Association of MRI findings and expert diagnosis of symptomatic meniscal tear among middle-aged and older adults with knee pain.

BACKGROUND: Our aim was to examine the association between an expert clinician's impression of symptomatic meniscal tears and subsequent MRI in the context of middle-aged and older adults with knee pain. METHODS: Patients older than 45 were eligible for this IRB-approved substudy if they had knee pain, had not undergone MRI and saw one of two orthopaedic surgeons experienced in the diagnosis of meniscal tear. The surgeon rated their confidence that the patient's symptoms were due to meniscal tear. The patient subsequently had a 1.5 or 3.0 T MRI within 6 months. We examined the association between presence of meniscal tear on MRI and the surgeon's confidence that the knee pain was due to meniscal tear using a χ(2) test for trend. RESULTS: Of 84 eligible patients, 63% were female, with a mean age of 64 years and a mean BMI of 27. The surgeon was confident that symptoms emanated from a tear among 39%. The prevalence of meniscal tear on MRI overall was 74%. Among subjects whose surgeon indicated high confidence that symptoms were due to meniscal tear, the prevalence was 80% (95% CI 63-90%). Similarly, the prevalence was 87% (95% CI 62-96%) among those whose surgeon had medium confidence and 64% (95% CI 48-77%) among those whose surgeon had low confidence (p = 0.12). CONCLUSION: Meniscal tears were frequently found on MRI even when an expert clinician was confident that a patient's knee symptoms were not due to a meniscal tear, indicating that providers should use MRI sparingly and cautiously to confirm or rule out the attribution of knee pain to meniscal tear.

Defining the Value of Future Research to Identify the Preferred Treatment of Meniscal Tear in the Presence of Knee Osteoarthritis.

BACKGROUND: Arthroscopic partial meniscectomy (APM) is extensively used to relieve pain in patients with symptomatic meniscal tear (MT) and knee osteoarthritis (OA). Recent studies have failed to show the superiority of APM compared to other treatments. We aim to examine whether existing evidence is sufficient to reject use of APM as a cost-effective treatment for MT+OA. METHODS: We built a patient-level microsimulation using Monte Carlo methods and evaluated three strategies: Physical therapy ('PT') alone; PT followed by APM if subjects continued to experience pain ('Delayed APM'); and 'Immediate APM'. Our subject population was US adults with symptomatic MT and knee OA over a 10 year time horizon. We assessed treatment outcomes using societal costs, quality-adjusted life years (QALYs), and calculated incremental cost-effectiveness ratios (ICERs), incorporating productivity costs as a sensitivity analysis. We also conducted a value-of-information analysis using probabilistic sensitivity analyses. RESULTS: Calculated ICERs were estimated to be $12,900/QALY for Delayed APM as compared to PT and $103,200/QALY for Immediate APM as compared to Delayed APM. In sensitivity analyses, inclusion of time costs made Delayed APM cost-saving as compared to PT. Improving efficacy of Delayed APM led to higher incremental costs and lower incremental effectiveness of Immediate APM in comparison to Delayed APM. Probabilistic sensitivity analyses indicated that PT had 3.0% probability of being cost-effective at a willingness-to-pay (WTP) threshold of $50,000/QALY. Delayed APM was cost effective 57.7% of the time at WTP = $50,000/QALY and 50.2% at WTP = $100,000/QALY. The probability of Immediate APM being cost-effective did not exceed 50% unless WTP exceeded $103,000/QALY. CONCLUSIONS: We conclude that current cost-effectiveness evidence does not support unqualified rejection of either Immediate or Delayed APM for the treatment of MT+OA. The amount to which society would be willing to pay for additional information on treatment outcomes greatly exceeds the cost of conducting another randomized controlled trial on APM.

Risk factors for revision of primary total hip replacement: results from a national case-control study.

OBJECTIVE: To study the risk factors for revision of primary total hip replacement (THR) in a US population-based sample. METHODS: Using Medicare claims, we identified beneficiaries from 29 US states who underwent primary THR between July 1, 1995 and June 30, 1996, with followup through December 31, 2008. Potential cases had International Classification of Diseases, Ninth Revision, Clinical Modification codes indicating a revision THR. Each case was matched by state with 1 control THR recipient who was alive and unrevised when the case had a revision THR. We abstracted hospital records to document potential risk factors. We examined the associations between preoperative factors and revision risk using multivariate conditional logistic regression. RESULTS: The analysis data set contained 719 of 836 case-control pairs with complete data for analysis variables. The factors associated with higher revision odds in multivariate models were age ≤75 years at primary surgery (odds ratio [OR] 1.52 [95% confidence interval (95% CI) 1.20-1.92]), height in the highest tertile (OR 1.40 [95% CI 1.06-1.85]), weight in the highest tertile (OR 1.66 [95% CI 1.24-2.22]), cemented femoral component (OR 1.44 [95% CI 1.10-1.87]), prior contralateral primary THR (OR 1.36 [95% CI 1.05-1.76]), other prior orthopedic surgery (OR 1.45 [95% CI 1.13-1.84]), and living with others (versus alone; OR 1.26 [95% CI 0.99-1.61]). CONCLUSION: This first US population-based case-control study of risk factors for revision of primary THR showed that younger, taller, and heavier patients and those receiving a cemented femoral component had a greater likelihood of undergoing a revision THR over a 12-year followup period. Effects of age and body size on revision risk should be addressed by clinicians with patients considering primary THR.

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.

Association between hospital and surgeon procedure volume and the outcomes of total knee replacement.

BACKGROUND: The annual volume of major cardiovascular and oncologic procedures performed in hospitals and by surgeons has been inversely associated with the rates of perioperative mortality and complications. The relationship between hospital and surgeon volume and perioperative outcomes following total knee replacement has received little study. METHODS: We analyzed claims data for Medicare patients who had elective primary total knee replacement between January 1 and August 31, 2000. Hospital and surgeon volumes were defined as the number of primary and revision total knee replacements performed in the hospital or by the surgeon in Medicare recipients in 2000. We examined the associations between the annual volumes of total knee replacement performed in the hospitals and by the surgeons and the rates of mortality and complications (infection, pulmonary embolus, myocardial infarction, or pneumonia) in the first ninety days postoperatively. The analyses were adjusted for age, gender, comorbid conditions, Medicaid eligibility (a marker of low income), and arthritis diagnosis. Analyses of hospital volume were adjusted for surgeon volume and vice versa. RESULTS: Twenty-five percent of the primary total knee replacements were done by surgeons who performed twelve of these procedures or fewer in the Medicare population annually, and 11% were done in hospitals with an annual volume of twenty-five of these procedures or fewer. Compared with the patients who had a primary total knee replacement in hospitals with an annual volume of twenty-five procedures or fewer, those managed in hospitals with an annual volume exceeding 200 procedures had a lower risk of pneumonia (odds ratio, 0.65; 99% confidence interval, 0.47 to 0.90) and any of the adverse outcomes examined (death, pneumonia, pulmonary embolus, acute myocardial infarction, or deep infection) (odds ratio, 0.74; 99% confidence interval, 0.60 to 0.90). Similarly, patients who had a primary total knee replacement done by surgeons who performed more than fifty such procedures in Medicare recipients annually had a lower risk of pneumonia (odds ratio, 0.72; 99% confidence interval, 0.54 to 0.95) and any adverse outcome (odds ratio, 0.81; 99% confidence interval, 0.68 to 0.98) compared with patients of surgeons with an annual volume of twelve procedures or fewer. CONCLUSIONS: Patients managed at hospitals and by surgeons with greater volumes of total knee replacement have lower risks of perioperative adverse events following primary total knee replacement. Patients and clinicians should incorporate these findings into discussions about selecting a surgeon and a hospital for total knee replacement. These data should also be integrated into the policy debate about the advantages and drawbacks of regionalizing total joint replacement to high-volume centers.