Cemented acetabular revision for the distorted acetabulum with intact columns (type IIA, B, and C defects)

Required equipment

Curved retractors are required for acetabular exposure. Usually, three retractors are placed around the acetabulum. One is superior/anterior at the acetabular rim, retracting the rectus femoris and sartorius muscles anterosuperiorly. The second one is placed medial to the transverse ligament, either pointed against the superior or the inferior horn or the semi-lunate fasciae. A third curved retractor is placed lateral to the acetabular rim. We use a fourth retractor at the dorsal acetabular rim to inferiorly retract the femur with the femoral stem in place. A double-pronged retractor such as a Mueller retractor is preferable in most cases ( Figs. 7.1 and 7.2 ).

The authors recommend performing this technique on a radiolucent Jackson table with fluoroscopic guidance. This procedure can also be performed with a specialized table.

Based on the literature, fresh frozen allograft bone is the preferred bone graft for this procedure. ^, However, a morselized bone graft can be augmented with bone substitutes and be impregnated with antibiotics. ^, This may, however, compromise the mechanical properties of the graft material.

For acetabular reaming, a curved or offset reamer handle should be available. We also recommend an offset impaction device. Those should also have some anterior offset or curvature to allow for soft-tissue preservation ( Fig. 7.3 ).

If an acetabular mesh is utilized, the initial fixation of this mesh should be performed with standard screws. Otherwise, the mesh could violate Köhler’s line and gain access to the pelvis during bone impaction or cup placement.

For central defects, it is sometimes necessary to place a metal mesh centrally to avoid medial migration of bone graft material. Ideally, different dimensions of round preformed meshes should be available at the time of surgery. Alternatively, the desired shape can also be created from a standard flat piece of mesh. If this is necessary, an appropriate pair of scissors should be at hand. If the defect is small and the fascia of the iliac muscle is intact or reinforced by preexisting scar tissue, no further reinforcement is necessary.

The concept of impaction bone grafting includes the use of a cage to augment the cement and contain and stabilize the morselized bone. A multi-layer augmentation is used to reconstruct the bone defect ( Fig. 7.4 ).

Several ring constructs are available for reconstruction. We recommend using a ring system that has superior and inferior bone contact. This is achieved with either a hook ( Fig. 7.4 ) or a spike ( Fig. 7.5 ).

We prefer using a ring with a hook and an additional plate laterally to achieve optimal load distribution.