The authors have developed a new external fixator for high tibial osteotomy to treat patients with medial osteoarthritis of the knee. Fifteen knees of 14 patients (5 males and 9 females, mean 64.1 years old) who underwent this treatment were followed up more than 2 years (mean 2.7 years). Surgical outcome was evaluated with the Japanese Orthopedic Association score (JOA score), femorotibial angle (FTA) and postoperative complications, The FTA significantly decreased from 182.4±3.2° to 167.8±2.4°. The JOA score significantly improved from 63.3±10.8 point to 80.0±13.4 point. There were no patients who showed peroneal nerve palsy, delayed union or deep infection. These results showed that high tibial osteotomy using this external fixator is effective for the treatment of the medial osteoarthritis of the knee.
