Objective To assess the efficacy of medial wedged proximal tibial osteotomy for treating knee osteoarthritis with varus deformity. Methods From July 1996 to September 1999, 19 patients with knee osteoarthritis accompanied by varus deformity were treated by medial wedged proximal tibial osteotomy combined with internal fixation. Full-length anteriorposterior radiographs were taken preoperatively, 8 weeks and 2 years postoperatively. The parameters including the femorotibial angle, the tibial angle, the femoral angle, the femoral condyletibial plateau angle, and the medial joint space, were measured from these radiographs. The function of knee was evaluated according to the 100point rating scale standard of knee.Results Themean postoperative score had been significantly improved from 48.6±16.6 pointsto 81.7±14.8 points after 2 years of operation. The medial joint spacehad been increased from 2.2±1.6mm to 4.9±1.5 mm and the femoral condyle-tibial anglehad been decreased from 7.4°±3.1° to 1.7°± 3.1°. There were complications in 3 cases: 2 casesof superficial wound infections and 1 case of intraarticular fracture. There were no delayed union and recurrence of varus deformity. Conclusion Medial wedged proximal tibial osteotomy combined with internal fixation provides an efficacious approach to treat knee osteoarthritis with varus deformity.