Fig. 8.

PAO osteotomes. 1 = 20-mm large osteotome with a 30° curve and no handle. It is used for the starting cut of the retroacetabular osteotomy at its supra-acetabular part. The same device without a curve can also be used. 2 = 20-mm large osteotome that is angulated 30° and has a handle and square shoulders. It was once applied for the first and last ischial cuts but is no longer in use. 3 = 20-mm large double-tipped osteotome with blunt edges that is angulated 30° at 40 mm from the cutting edge and has sloping shoulders. It is used for the inside-out cut of the retroacetabular osteotomy. 4 = 15-mm large double-tipped osteotome with blunt edges, a 30° curve, and no shoulders. The complete absence of shoulders prevents tethering. The osteotome is primarily used for the first ischial cut.