Rationale of periacetabular osteotomy and background work.

The Bernese periacetabular osteotomy is a joint-preserving procedure used after growth plate closure to correct acetabular coverage and stabilize the femoral head. The polygonal, juxta-articular osteotomy respects the vascular blood supply to the acetabular fragment and facilitates an extensive acetabular reorientation. It achieves improvement of the insufficient coverage of the femoral head, reduction of mediolateral displacement, and correction of the version of the fragment. All osteotomies are performed through the modified Smith-Petersen approach, which also allows for an anterior capsulotomy. Joint inspection not only provides information on lesions of the rim but also facilitates the control of an impingement-free range of motion after the correction. The posterior column remains partially intact, allowing minimal internal fixation of the acetabular fragment and early mobilization similar to that after an intertrochanteric osteotomy. Because the majority of this patient population consists of young women, it is important to note that the dimensions of the true pelvis and thus the potential for future vaginal delivery are preserved.