Intermediate-term results with a modified antiprotrusio cage in acetabular revision surgery.

A modified antiprotrusio cage and cemented cup were implanted in 11 patients who required acetabular revision surgery. Acetabular defects were classified as combined in 8 hips, pelvic discontinuity in 2, and cavitary in 1. Cancellous allograft was used in all patients, and 4 required structural allografts. Mean operative time was 324 minutes (range, 273-434 minutes), and mean estimated blood loss was 1168 mL (range, 500-4000 mL). Mean clinical and radiographic follow-up was 6.1 years (range, 2-8.8 years). Aseptic loosening occurred in 2 hips, 1 of which was revised. There were no dislocations, no deep infections, and no neurovascular injuries. Mean postoperative Harris hip score was 76 (range, 49-97). In a comparison with historical controls, this cage, which facilitates anteversion of the cemented cup, was found to improve hip stability. Massive defects and poor ischial fixation were common in the cases of loosening.