Femoral neck rotational osteotomy: a modified method for treating necrotic femoral heads with large and laterally located lesions

In this study, we retrospectively investigated the short-term outcome of femoral neck rotational osteotomy (FNRO) for treating necrotic femoral heads with large and laterally located lesions. Twelve necrotic femoral heads (ARCO stage II or III) with an average Kerboul angle of 210° underwent FNRO through surgical hip dislocation. By circumferential release of capsule and retinaculum, femoral neck osteotomy was performed at the base of femoral neck just 1.5 cm above lesser trochanter. The severed femoral neck was rotated with a mean angle of 120.4° and fixed with a mean varus angulation of 10.2°. Both Harris hip score and International hip outcome tool improved at a mean follow-up of 29 months. The average post-operative intact rate was 55.3%. Subsequent collapse or progression to osteoarthritis was found in four hips but only one hip failed with a Harris hip score of 44 and converted to hip replacement. Post-operative leg length discrepancy was 1.1 cm. Limp presented in seven hips. Six hips had osteophyte formation. FNRO through surgical hip dislocation had the advantages of safe exposure, direct visualization of necrotic lesion and high reorientation of healthy bone and articular cartilage on femoral head. We observed satisfactory short-term survivorship and improved patient-reported outcomes in necrotic femoral heads treated with FNRO.