The prevalence of knee pain and symptomatic knee osteoarthritis among veteran traumatic amputees and nonamputees.
OBJECTIVE: To determine whether amputees have an increased risk of knee pain or symptomatic osteoarthritis (OA) compared with nonamputees. DESIGN: Retrospective cohort study. SETTING: Veterans Administration Patient Treatment and Outpatient Care files. PARTICIPANTS: All male unilateral (transtibial or transfemoral) traumatic amputee patients and a random sample of male nonamputees. Patients were excluded if they were younger than 40 years, had sustained a significant injury to their knee(s), or had a rheumatic disease. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The prevalence of knee pain and symptomatic knee OA. RESULTS: The age and average weight-adjusted prevalence ratio of knee pain among transtibial amputees, compared with nonamputees, was 1.3 (95% confidence interval [CI], 0.7-2.1) for the knee of the intact limb and 0.2 (95% CI, .05-0.7) for the knee of the amputated limb. The standardized prevalence ratio of knee pain in the intact limb and symptomatic OA among transfemoral amputees, compared with nonamputees, was 3.3 (95% CI, 1.5-6.3) and 1.3 (95% CI, 0.2-4.8), respectively. CONCLUSIONS: Stresses on the contralateral knee of amputees may contribute to secondary disability. Possible explanations include gait abnormalities, increased physiologic loads on the knee of the intact limb, and the hopping and stumbling behavior common in many younger amputees.