Surgical dislocation of the adult hip: A technique with full access to the femoral head and acetabulum without the risk of avascular necrosis

Abstract

Background Surgical dislocation of the hip is rarely undertaken because of the potential dangers to the vascularity of the femoral head and risk of subsequent AVN. The authors describe a new technique for surgical dislocation of the hip and report their experience in 231 patients. Previous work by the same authors [ 1[ studied the blood supply to the femoral head which is mainly derived from the deep branch of the medial femoral circumfl ex artery. In this new technique, the hip is approached using a trochanteric fl ip osteotomy. The vessel is protected by avoiding division of the obturator externus muscle. The hip is exposed posteriorly, subluxated and dislocated anteriorly whilst respecting the integrity of the external rotator muscles. This allows a gap of up to 11 cm between the head and the acetabulum, giving a view of the femoral head of about 360° and a full 360° view of the acetabulum. Methods A case series of 213 patients underwent surgical dislocations of the hip for various indications such as impingement, pigmented villonodular synovitis, synovial chondromatosis or cartilaginous exostosis. Follow-up ranged from 2 to 7 years with yearly clinical and radiological assessment. Results There were 109 women and 104 men with a mean age of 33.5 years (16-58). The mean blood loss was 300 ml. There were no hips reported that had permanent weakness of the abductor muscles, that could be attribute to the approach. Although, pain and range of motion were not the primary outcome of the operation, most patients had improved hip movement and decreased pain with no increase in pain or stiffness that could be related to the approach. Two patients who had undergone previous surgery developed a neurapraxia of the sciatic nerve that fully resolved within 6 months. Trochanteric fi xation failed in three patients, requiring a second operation. Heterotopic ossifi cation was seen in 79 hips at 1 year with an overall incidence of 37 %. Most were Brooker grade I. Conclusions The Ganz technique of surgical dislocation allows excellent access to the femoral head and the acetabulum. Intra-articular surgery can be carried out safely, without the limitations and diffi culties inherent in hip arthroscopy or arthrotomy without dislocation. Iatrogenic injury to the cartilaginous surfaces of the femoral head and acetabulum is minimized.