Figure 5.

The sequence of periacetabular osteotomies is performed under fluoroscopic guidance. The first bone cut is the ischial osteotomy which is an incomplete osteotomy of 2.0–2.5 cm using a curved “Ganz” osteotome just inferior to the acetabulum [(A) the anterior to posterior fluoroscopic view and (B) a 65° lateral “false profile” view]. The second osteotomy is done at the superior pubic rami with osteotomes or a small saw. The third is the transverse iliac osteotomy (C). Mark with fluoroscopy starting just distal to the anterior superior iliac spine aiming slight proximal, stop 1 cm lateral of the pelvic brim. The fourth and last osteotomy is the retroacetabular osteotomy that connects the first ischial with the third transverse iliac osteotomies. Use fluoroscopy (65° “false profile” view) to facilitate this osteotomy and avoid exiting into the hip joint or posterior column (D). Once complete, the fragment should be mobile and ready for acetabular correction. Use a Schanz pin in the mobile fragment to facilitate control and mobilization of acetabulum (E). Correct the anteversion of the mobile fragment, pin it, and check the hip range of motion (F). Adapted with permission from Dr. Robert T. Trousdale and the Mayo Foundation, Rochester, MN, USA.