Operative and postoperative findings in case 3. (A) Arthroscopy showing the lesion of the osteonecrosis at the medial condyle of the femur demonstrating the anterior wide margin of the femoral condylar defect. (B) Osteochondral plugs are grafted into the recipient site. (C) Anteroposterior radiograph taken six months after surgery shows less irregularity of the subchondral bone of the medial femoral condyle. (D, E) MRI taken six months after surgery shows the restoration of the articular cartilage surface and good engraftment of the graft.