Prof. Dr. med. Dietrich Tönnis

In my training in Berlin with Prof. A.N. Witt between 1960 and 1968 we started with these pictures of a complete transversal acetabuloplasty combined with an intertrochanteric varus osteotomy, and worked on the final form later in Dortmund (Fig. 1).

I would like to show you our technique and you will notice what is different (Fig. 2).

The inguinal incision is our preferred approach for open reductions of the hip and the transiliac osteotomy (Fig. 3). The scares are almost invisible. The incision starts from the anterior iliac crest to the groin parallel to the inguinal ligament. The tensor fasciae latae and the sartorius muscle are released ventrally. The detachment of the gluteus muscles in a length of 4-5 cm should be performed at the cartilage on top of the iliac crest, leaving a small stripe of cartilage at the muscle fibers to reinsert them here afterwards. The muscle fibers themselves should not be cut. The gluteus muscles then are carefully stripped subperiostally with a wide elevator down to the joint capsule and the lateral insertion of the rectus muscle tendon. This region should not be traumatized since the lateral growth centers are responsible for the growth of the acetabular rim till the end of growth.

The inguinal ligament, abdominal muscles and iliacus muscle are also detached at the iliac crest, so that we see the blade of the osteotome anteriorly as it enters the inner side of the pelvis.

Then the glutaeus muscles above the capsule are stripped subperiostally back, up to the greater sciatic notch, until a finger can control the osteotomy as you see it here. The gluteus muscles should be retracted gently and by double rounded retractors. The superior gluteal nerve is close underneath this surface. A leasion causes limping.

We osteotomize the acetabular roof 6-8 mm above the lateral acetabular margin using a flat Lexer osteotome (Fig. 4). The operation is performed on a radiolucent table. Using an image intensifier, the blade of the osteotome is driven toward the posterior rim of the triradiate cartilage. It should stop 5 mm before it. Anteriorly the blade passes through the anterior inferior iliac spine. Posteriorly it just enters the sciatic notch. There we check the blade position by palpation. The bone must be cut through completely from its anterior side back into the sciatic notch.

Then a good turn-down of the acetabular roof is possible. The hinge is placed by the 2 or 2,5 cm broad blade of the chisel, parallel to the posterior triradiate cartilage, at the medial side of the pelvic wing (Fig. 5).

The acetabular roof is turned down in the bone 5 millimeters apart of the triradiate cartilage. An angle of 5-10° should be achieved. 7 years later we find a perfect joint and coverage, here without a varus osteotomy. We shall come to this point.

Our maximal angle of correction has been 50°. Here a deep frozen bone wedge from the bone bank has been pushed in medially and a peace of bone from the shortening osteotomy laterally (Fig. 6)

A hip spica in slight flexion of about 25° relieves the pressure on the femoral head.

When acetabuloplasty is combined with an open reduction and the dislocation was high, a subtrochantery shortening osteotomy is added to avoid ischemic necrosis of the femoral head (Fig. 7). A metal plate with 4 screws is sufficient since the child has to stay in a hip spica anyway and this is easier to perform than an intertrochanteric osteotomy.

These patients had a tilt of the femoral head or it is called a subcapital coxa valga after varus osteotomy as you see it here (Fig. 8).

Ever since we avoided varus osteotomies.

Later the whole acetabulum has to be rotated after disconecting it from the ligaments to the os pubis, os ischium and os ilium by a socalled triple pelvic osteotomy (Fig. 9).

But this operation is more difficult and takes a longer time to recover. Residual dysplasias therefore should be treated as early as possible as we discussed it.