Principles of bone grafting in revision total hip arthroplasty. Acetabular technique.

Multiple revisions of the acetabulum ultimately lead to severe loss of bone stock. Each bone loss type requires a specific method of allograft reconstruction to achieve acetabular component stability. A series of 316 acetabular revisions in which 69 required support allograft were followed for a mean of 5.1 years (range, two to ten years). Support allograft was required when radiographs showed superior component migration greater than 2 cm. Severe ischial lysis was indicative of posterior column insufficiency. Distal femurs were used instead of femoral heads as support for porous-coated cups. If in addition to the radiographic findings, Kohler's line also was violated (which was indicative of anterior column deficiency as well), then whole acetabular allografts were used with cemented polyethylene cups. Biologic fixation of a porous-coated cup and support allograft were not possible in these cases. All of the distal femoral allografts united to host bone, and there was no migration of porous-coated components at a mean of 5.1 years when Kohler's line was intact. When Kohler's line was not intact, 70% of the porous cups had migrated more than 4 mm and were considered failures. Conversely, when whole acetabular allografts with cemented polyethylene cups were used in these cases, all 14 showed graft union and no change in the cement-graft interface at a minimum follow-up period of 24 months. The postoperative clinical results using the D'Aubigne and Postel rating scales were 10.1 of 12, with 76% good to excellent results. This study indicates that better results with support allografts can be achieved at similar periods than has previously been reported.