(iii) Bernese periacetabular osteotomy

SummaryThe Bernese Periacetabular Osteotomy (PAO) is a reorientation procedure of the dysplastic acetabulum and was first executed in 1984 after extensive feasibility studies in the anatomy lab including injection studies of the blood supply of the periacetabular bone. Dissatisfaction with available techniques led to the new procedure with its power of correction and intracapsular access, avoiding the danger of avascular necrosis. It should not interfere with the natural birth canal. The approach was chosen to produce little morbidity and reduced care in the postoperative period. The resulting procedure using a Smith–Peterson approach evolved to one of the most frequently executed reorientations of today, although the execution is technically rather demanding. Reorientation of the acetabulum became the most successful operation in our armamentarium to preserve the natural joint. Addressing the tendency to produce acetabular retroversion and an eventually insufficient head–neck offset has helped to avoid impingement after reorientation and has further improved the results.Combined pathology of acetabulum and proximal femur is not treatable via a Smith–Peterson approach so a feasibility study on cadavers was undertaken to achieve acetabular and femoral correction using one posterolateral approach. Again, injection studies have shown how interference with the periacetabular bone perfusion can be avoided, even when performing a large capsulotomy with dislocation of the femoral head. The technique has been tested successfully clinically, although the number of cases is still small.