We previously reported the results of the use of a cementless acetabular shell for revision total hip arthroplasty in 138 hips at a minimum of three, seven, and fifteen years postoperatively. The current report presents the long-term outcomes of this group at a minimum follow-up of twenty years.
Since the last report, two additional hips required repeat revision, both for infection; no additional acetabular shell was loose. In the entire series to date, repeat acetabular revision was performed in twenty-one (15%) of the original 138 hips. Twenty of the twenty-one shells were well fixed at the time of repeat revision, and one had become aseptically loose. The most common reasons for repeat revision were infection (eight hips) and recurrent instability (eight hips). In the metal shells that were well fixed, an isolated liner change for polyethylene wear and/or osteolysis was performed in a total of six hips; four of these liner exchanges were performed since the time of our last report. A liner change had been recommended because of severe wear in four additional hips; thus, 18% of the fifty-six unrevised metal shells were associated with polyethylene wear-related problems. Survivorship, with revision of the shell for aseptic loosening or radiographic evidence of loosening as the end point, was 95% at twenty years (95% confidence interval, 83% to 98%).
Reoperations for wear and osteolysis were first seen at approximately twelve years postoperatively. At the time of the present long-term follow-up, the reoperation rate for polyethylene wear and/or osteolysis had increased. We continue to use a hemispherical, titanium metal shell with multiple screws for fixation in the majority of acetabular revisions.
Level of Evidence: Therapeutic Level IV. See Instructions to Authors for a complete description of levels of evidence.