Tibial osteotomy proximal to the tuberosity is a successful method of treating osteoarthritis of the knee joint with a axial deformity. The clinical results of 54 osteotomies carried out between 1971 and 1975 show significant pain relief after correction of the deformity. There were only a few complications. Internal fixation by plates or other devices is superflous. A single staple is sufficient to allow early movement and weight-bearing because of the broad contact of cancellous bone at the osteotomy site. So this operation is the method of choice especially in the elderly patient with cardio-vascular disease. In the case of failure of the osteotomy other salvage procedures as well as joint replacement are still possible.