Revision of the acetabular component of a total hip arthroplasty with a massive structural allograft. Study with a minimum five-year follow-up.

The results of the placement of a massive structural acetabular allograft in conjunction with a revision total hip arthroplasty in thirty-two patients (thirty-tree hips) were evaluated at a minimum of five years. The graft supported more than 50 percent of the cup in all of the patients. The goals of a revision operation in a hip that has massive loss of bone are to provide support for the cup, to approximate the normal anatomy, to restore the length of the lower limb, and to restore bone stock should a future revision be necessary. Clinical and radiographic review at an average of seven years (range, five to eleven years) after the revision revealed that eighteen hips had needed no additional operation, seven hips had needed a repeat revision but the structural allograft was intact and had been used to support the cup at the repeat revision, and eight hips had had failure of both the prosthesis and the allograft. The result was considered a clinical and radiographic success when the hip score had increased at least 20 points, the cup was stable, the allograft had united, and no additional operation was necessary. According to these criteria, the rate of success was 55 percent (eighteen of thirty-three hips.) The only factor that was found to be clinically important with respect to outcome was the method of reconstruction. Seven of the eight hips that had been reconstructed with use of a roof-reinforcement ring and a structural allograft had a successful result at an average of 7.5 years (range, five to eleven years). The findings of the present study support the use of a structural allograft in the presence of massive loss of bone in order to achieve the goals of a revision hip replacement. Because of the high rate of success with acetabular reinforcement rings, we now use this method of reconstruction whenever a massive allograft is employed on the acetabular side.