Position of the Patient

The patient is placed in a lateral position on the unaffected side. The table is tilted 20 degrees posteriorly, the osteotomy of the superior pubic ramus is performed through a lateral ilioinguinal approach, the table is brought back to neutral position, and the rest of the osteotomy cuts with the greater trochanteric osteotomy are done through a posterior (Kocher-Langenbeck) approach.

Landmarks and Skin Incisions

Two lines are drawn on the patient’s skin. One line is drawn from the anterosuperior iliac spine to a point 3 cm proximal to the symphysis pubis; the incision is made on the lateral half of this line. The second line is drawn along the posterior border of the proximal femur and the greater trochanter, and extended proximally to within 6 cm of the postero-superior iliac spine.

Superficial and Deep Surgical Dissection

After the anterior skin incision is made, the external oblique aponeurosis is incised; blunt dissection is performed until the superior pubic ramus is palpated and exposed subperiosteally. The posterior incision is made and dissection continued into the subcutaneous fat and iliotibial tract. Drilling for two screws in the greater trochanter is done. The trochanter is osteotomized and reflected proximally with the attached abductor muscles. The short external rotators are divided with incision of only the superior part of the quadratus femori. With the periacetabular area now widely exposed, Hohmann retractors are placed.

Pelvic Osteotomy

The first osteotomy is the osteotomy of the superior pubic ramus, with care to cut completely the periosteal sleeve to avoid hindering the acetabular reorientation. The osteotomy is done just medial to the iliopectineal eminence to avoid creating an intraarticular osteotomy. The next cuts are made in the periacetabular area through the posterior approach under direct vision of the outer pelvic surface; the periacetabular osteotomy is done using a straight osteotome in three cuts. The first is an incomplete ischial cut, the second a transverse cut at least 3 cm proximal to the acetabulum on the exposed outer table of the pelvic brim aiming at, but not reaching, the greater sciatic notch, and the third a vertical cut posterior to the acetabulum, leaving an intact posterior column.

Acetabular Reorientation

A 5-mm Schanz pin is placed in the supraacetabular area to allow manipulation of the acetabular fragment.

Radiographic Assessment

The fluoroscopy unit is moved to allow an anteroposterior pelvic view. The fragment usually is manipulated in flexion, followed by lateral rotation, and the position is checked by fluoroscopy.

Fixation

? The periacetabular osteotomy is fixed by two cancellous screws under direct vision starting from the acetabular roof area and aiming proximally, directed in a divergent manner, the greater trochanter is reduced to its position and fixed by the predrilled cancellous screws.