83 patients (87 knees) with non-inflammatory osteoarthritis of the knee were included in this study to evaluate the effect of femoral inserts on bone mineral density over a 5 year period. Only 47 knees completed the 5 year follow-up. Patients with less severe pre-operative deformity (5 degrees or less varus/valgus) were randomized to receive a flat or a concave tibial insert with the posterior cruciate ligament retained. Patients with more severe deformities were randomized to receive either a concave or a posterior-stabilized (PS) insert with resection of the posterior cruciate ligament. Over 5 years, there was no difference in bone mineral density between the two groups of patients with less severe deformity. In the patients with more severe deformity, those who received PS inserts demonstrated greater bone loss posterior to the anterior flange than those who received concave inserts.