WHC Rijnen, BW Schreurs, JWM Gardeniers

Department of Orthopaedics, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands

Osteonecrosis of the distal femur produces a segment of dead bone in the weight-bearing portion of the femoral condyle, frequently associated with subchondral fracture and collapse, and eventually resulting in secondary osteoarthritis. We developed a new surgical technique; the osteonecrotic lesion was removed and impacted bone grafts were used to regain sphericity and prevent collapse. In this prospective one surgeon study, we included 9 consecutive knees (6 patients) with extensive steroid associated osteonecrotic lesions of the femoral condyles. A new staging system was developed that includes location and quantification of the osteonecrotic lesion. Six knees showed a preoperative collapse. The mean age of the patients was 31 years (range, 16-47 years). At a mean follow up of 51 months (range, 29-93 months) no conversion into total knee arthroplasty was performed. The objective knee society score improved from 63 to 89 points. The functional knee society score improved from 19 to 81 points. At follow up there was no progression of collapse observed and only 3 knees showed slight signs of osteoarthritis. The clinical success rate was 75% and 78% was radiologically successful. This method is attractive as a salvage procedure, is relatively simple and quick and does not interfere with an eventual future total knee arthroplasty.