Extra-large uncemented hemispherical acetabular components for revision total hip arthroplasty

Background: Extra-large uncemented components provide several advantages fo r acetabular revision, but limited information is available on the results of their use. The purpose of this study was to evaluate, at a minimum of fi ve years, the results associated with the use of an extra-large uncemented porous-coated component for acetabular revision in the presence of bone los s. Methods: Eighty-nine extra-large uncemented hemispherical acetabular compon ents were used for revision after aseptic failure of a total hip arthroplas ty in forty-six men and forty-three women (mean age at revision, fifty-nine years; range, thirty to eighty-three years). The revision implant (a Harri s-Galante-I or II cup fixed with screws) had an outside diameter of greater than or equal to 66 mm in men and greater than or equal to 62 mm in women. Seventy-nine patients had a segmental or combined segmental and cavitary a cetabular bone deficiency before the revision. Particulate bone graft was u sed in fifty-four hips and bulk bone graft, in nine. Results: One patient died with the acetabular component intact and two pati ents were lost to follow-up within five years after the operation. At the t ime of the last follow-up, four acetabular components had been removed or r evised again (two for aseptic loosening). All of the remaining patients wer e followed clinically for at least five years (mean, 7.2 years; range, 5.0 to 11.3 years). In the hips that were not revised again, only two sockets h ad definite radiographic evidence of loosening. All four of the sockets tha t loosened were in hips that had had combined cavitary and segmental bone l oss preoperatively. In the hips that were not revised again, the mean modif ied Harris hip score increased from 56 points preoperatively to 83 points a t the time of the most recent follow-up. The most frequent complication, di slocation of the hip, occurred in eleven patients. The probability of survi val of the acetabular component at eight years was 93% (95% confidence inte rval, 85% to 100%) with removal for any reason as the end point, 98% (95% c onfidence interval, 92% to 100%) with revision for aseptic loosening as the end point, and 95% (95% confidence interval, 88% to 100%) with radiographi c evidence of loosening or revision for aseptic loosening as the end point. Conclusions: This study demonstrates that extra-large uncemented components used for acetabular revision in the presence of bone loss perform very wel l and have a low rate of aseptic loosening at the time of intermediateterm follow-up.