After removal of the proximal section of the fibula, patients with medial compartment knee OA showed greater improvement in alignment, knee range of motion and pain at an early stage.The goal of this study to assess clinical outcomes of patients with medial compartment osteoarthritis treated by proximal fibular osteotomy. A total of 40 patients were included in this study for follow–up of 12 months. At final follow–up, mean lateral joint space were and 6.2±0.5 mm which were significantly lower than preoperatively. Mean KSS at final follow–up was 90.7±29.5, which was significantly larger than the preopera¬tive score (43.0±19.3). Mean VAS score at final follow–up was 1.7±1.57 which was significantly lower than the preoperative data (7.73±0.88). Four patients subsequently un¬derwent total knee arthroplasty at a mean of 10.2 months (range, 8–12 months).