Treatment of osteonecrosis of femoral head with modified lightbulb operation: A 10-year follow-up study

Abstract

Objective: To retrospectively analyze the clinical efficacy of a modified light bulb operation for the treatment of femoral head osteonecrosis. Methods: A total of 38 patients (59 hips) were treated with this procedure between June 2004 and June 2005, and were followed up for over 10 years. They were classified into ARCO stage II (23 hips), stage IIIa (29 hips) and stage IIIb (7 hips); and into the China- Japan Friendship Hospital (CJFH) type C (3 hips), type L1 (7 hips), type L2 (19 hips) and type L3 (30 hips). In the operation, a bone window was made at the femoral head-neck junction. Autologous cancellous bone harvested around the window was mixed with recombinant human bone morphogenetic protein-2 (rh-BMP2), implanted to the subchondral bone and impacted. The cavity was filled with tricalcium phosphate porous bioceramic (Bio- TCP). The Harris hip score was used to evaluate the postoperative improvement of hip function. Excellent, good, fair, and poor results were defined as Harris hip scores of 90-100, 80-89, 70-79 and below 70, respectively. Harris hip scores ＞ 70 were defined as clinical successful. The radiographic follow-up was evaluated by X-ray and CT scan before and 3, 6, 12 months and every year after the treatment. No presences of collapse, crescent sign or narrower joint space were defined as radiographic successful results. Results: Six patients (9 hips) were lost in the follow-up. Of the rest, excellent, good, fair and poor functions were obtained in 30, 6, 5 and 9 hips, respectively. All the failed cases had total hip replacement. The average preoperative Harris hip score of all hips was 60.2 points. The average postoperative Harris hip score was 87.3 points at 10 years after the surgery, with an increase of 27.1 points (p ＜ 0.001). The radiological results were successful in 76% of the hips with preserved spherity of the femoral head and incorporation of the grafts in the femoral heads could be found. Conclusion: (1) The modified lightbulb operation used local cancellous grafts from the femoral head and expanded its volume with Bio-TCP and rhBMP-2. An overall 82% clinical successful rate and 76% radiographic successful rate was achieved with a mean follow-up of 10 years. (2) The operation did not need other autologous grafts to avoid donor site morbidity and was technically easy to perform. Grafts supporting to the lateral column in the necrotic area were found to be the most important determinant to prevent subsequent collapse of the femoral head.