Which patients with knee problems are likely to benefit from nonarthroplasty surgery? Development of a clinical prediction rule.

BACKGROUND We examined factors associated with the clinical presentation of patients judged likely by orthopedic surgeons to benefit from nonarthroplasty knee surgery. METHODS Consecutive patients presenting to orthopedic surgeons were eligible for the study and 103 were recruited. A trained research assistant took histories, performed physical examinations, and administered a standardized questionnaire. Surgeons provided diagnoses and, in each case, rated their confidence that nonarthroplasty knee surgery would help the patient. We assessed the relationship between patient characteristics and the orthopedic surgeon's level of confidence that the patient was likely to benefit from knee surgery. RESULTS In multivariable logistic regression models, the following characteristics were associated with a surgeon's judgment that a patient would likely benefit from knee surgery: a history of sports-related trauma, low functional status, limited knee flexion or extension, medial or lateral knee joint line tenderness, a click or pain noted with the McMurray test, and a positive Lachmann or anterior drawer test (c statistic from model, 0.83). These items were combined into a clinical prediction score, and low-, medium-, and high-risk categories were identified. Independent evaluation by surgeons indicated that only 8% of patients in the low-risk category but 84% of patients in the high-risk category were judged likely to benefit from surgery (P for trend <.001). CONCLUSION Using a small group of easily accessible patient characteristics, we developed a clinical prediction score that clearly differentiated patients who were viewed by experienced orthopedic knee surgeons as likely or not likely to benefit from nonarthroplasty knee surgery.