[Peri-acetabular reorientation osteotomy]

A new technique to plan and perform a reorientation pelvic osteotomy around the hip joint in adolescents and adults is described. Planning is based on 3-dimensional reconstruction of the hip joint. The operation is simulated by computer before surgery to find the correction angles which optimize alignment both quantitatively (amount of femoral head covered) as well as qualitatively (joint congruency). These angles are then utilized at the time of surgery. A Smith-Petersen approach is always used to perform the osteotomy. The pelvic ring is not displaced, but nevertheless the acetabular fragment can be tilted without limitation around all 3 axes. Furthermore, linear displacement permits medialization of a lateralized hip joint. Stability is obtained by simple screw fixation. The posterior column remains mechanically intact, and thus no cast is required. Since 1984, about 200 peri-acetabular osteotomies have been performed. The success of correction was evaluated on plain radiographs using A P and "false profile" views as well as by CT. Conventional radiographs showed fully normalized VCE (Wiberg) and VCA (de Sèze and Lequesne) angles and well-centered joints on the CT-based reconstructions. Four types of complications occurred: there were 2 cases with intra articular extension of the osteotomy; 1 transient femoral neuropraxia; 2 non-unions and 4 cases with ectopic ossifications which limited motion of the joint. The latter problem appear to have been eliminated by the administration of prophylactic indomethacin. Symptomatic fixation screws had to be removed after union in 13 cases.