OBJECTIVETo analyze the mid-term clinical and radiographic results obtained with the Bernese periacetabular osteotomy for the treatment of severe hip dysplasia.

METHODSFrom October 1997 to December 2002 20 hips of 18 patients were classified as having severe acetabular dysplasia (Severin classification Grade IVb). Preoperatively, all patients had hip pain, and sufficient hip joint congruency on functional radiographs. All 20 hips underwent Bernese periacetabular osteotomy. Postoperatively, the hips were assessed radiographically on center edge angle (CE), acetabular roof obliquity and the progression of osteoarthritis. Clinical results and hip function were measured with the Harris hip score at an average of 6.2 years follow-up.

RESULTSComparison of preoperative and follow-up radiographs demonstrated significant improvements in the lateral CE angle, the anterior CE angle, and roof obliquity. The average Harris hip score improved from 78.5 points preoperatively to 91.1 points at the time of the latest follow-up. Fourteen of 18 patients were satisfied with the result of the surgery, and 16 of 20 hips had a good or excellent clinical result. Under-correction occurred in 5 hips.

CONCLUSIONSThe Bernese periacetabular osteotomy is an effective procedure for surgical correction of the severe dysplastic hip. This osteotomy can predictably obtain major reorientation of the acetabulum in all planes. The clinical results in the mid-term follow-up are encouraging.