Knee sports injury is associated with an increased prevalence of unilateral knee replacement: a case-controlled study

Injury to the knee during athletics is common and may limit future sports participation, but its long-term effects on patients are less well characterized. Examining the development of end-stage osteoarthritis (OA) in these patients may help better clarify this relationship. We hypothesize that sports-related knee injuries are associated with subsequent unilateral knee OA and need for total knee arthroplasty (TKA) relative to bilateral knee replacement. We present a single-hospital case-control study of 124 consecutive patients undergoing primary TKA over a 6-month period for end-stage OA. Patients were interviewed at the time of surgery using a standardized questionnaire to detect and characterize a history of athletic knee injury. The presence of contralateral knee arthritis based on preoperative assessment was noted for all patients. A control population was derived from patients with diagnosed or known bilateral OA undergoing TKA. Patients were all assessed for exposure to earlier sports or athletic injury. Prestudy power analysis and uni- and multivariate statistical analyses were performed. Of the 124 patients, 27 (22%) recorded a history of athletic knee injury. Evidence of bilateral significant knee OA was found in 73 patients and unilateral arthritis in 51 patients. Patients with unilateral OA were found to have an increased likelihood of previous athletic injury relative to those with bilateral disease (odds ratio: 6.08, p = 0.0001). There is a significant prevalence of sports-related injuries in patients with unilateral knee OA. This study suggests that patients with such injuries may develop arthritis via a different process, sports-related trauma, than patients with bilateral nontraumatic OA.