In seventy-one patients with degenerative arthritis and sixteen with quiescent rheumatoid arthritis, proximal tibial or femoral osteotomy was performed for varus or valgus deformity. The correction needed was gauged in standing roentgenograms. After one to nine years, the patients with either form of arthritis had good or fair results in all but three cases in each group, gauged mostly by relief of pain, since the range of motion did not change. The results tended to be better in patients with lesser degrees of arthrosis.