- To assess the prevalence of osteoarthritis (OA) of the contralateral knee of men with traumatic amputation who do and do not participate in regular, vigorous physical activity. Three groups of patients were assessed. Group 1 consisted of 8 male amputee volleyball players. Group 2 consisted of 24 male amputees who do not play volleyball, and Group 3 was made up of 24 healthy controls matched by age and weight to Group 2. The prevalence of contralateral knee OA in Groups 1 and 2 was assessed by questionnaire, physical examination, and radiographs, and was compared with findings for Group 3. The rate of OA in all amputees (Groups 1 and 2 together) was 65.6%, which was significantly higher than among the controls (p < 0.05). The most common findings among the amputees were patellar and medial osteophytosis of the tibiofemoral joint, with a tendency to medial narrowing of the tibiofemoral joint space. Traumatic amputees have a higher prevalence of OA in the knee of the nonamputated leg than matched healthy controls.