Results of Transtrochanteric Curved Varus Osteotomy for Osteonecrosis of the Femoral Head
T Yamamoto, S Jingushi, G Motomura, Y Nakashima, T Shuto, Y Sugioka, Y Iwamoto
Department of Orthopaedic Surgery, Kyushu University School of Medicine, Fukuoka, Japan

Objectives: When osteonecrosis locates in the medial portion, transtrochanteric curved varus osteotomy (varus) is indicated, in which the lateral intact area is transposed to the weight-bearing portion. The purpose of this study is to evaluate its clinical outcomes.

Patients: Cases consist of 60 hips in 52 patients with osteonecrosis of the femoral head, who had been performed varus osteotomy from 1981 to 1998. Fifty-five hips out of 60 were followed (follow-up rate: 92%; 5 hips dropped out). The underlying causes were idiopathic (8 hips), alcoholic (5), traumatic (2), and corticosteroid-induced (40). Nineteen were male, and 36 were female. The average age was 34 at the time of surgery. Forty-three hips were in ARCO stage III-A, 11 in Stage III-B, and 1 in stage IV.

Results: The average follow-up duration was 8.1 years (0.8 to 20). The average preoperative Harris Hip Score of 51 points improved to an average of 81 at the latest follow-up. Radiographically osteonecrosis in 46 hips (84%) healed or had no progression of collapse. Nine hips (16%) showed osteoarthritic changes, including progression of collapse, in which 4 cases had undergone conversion to THA. The post-operative intact area ratio in these 4 cases was 16%, while that in the other 51 cases was 70% (p<0.005).

Conclusion: When the intact area remains at the lateral portion of the femoral head, varus osteotomy is useful not only for healing of the necrotic lesion but also for the prevention of osteoarthritis. If the intact ratio is over 34 % with hip abduction, varus osteotomy is indicated.