Minor column structural acetabular allografts in revision hip arthroplasty.

A minor column (shelf) allograft is used for uncontained defects that involve less than 50% of the acetabulum. The prospectively collected records and radiographs of 47 patients (51 hips) who had undergone minor column structural acetabular allograft reconstruction during revision hip arthroplasty were reviewed. The purpose was to identify the long-term results (minimum 5 years) and factors that may influence longevity of the allograft and predispose the patient to subsequent acetabular component failure. The mean duration of followup was 119 months (range, 68-195 months). There was one perioperative death and six patients were lost to followup. Eleven patients (22%) required additional surgery. Three acetabular cups could not be revised successfully, despite multiple attempts, and the patients were treated with Girdlestone excisions. Eight patients underwent successful revision surgery with only three requiring a repeat structural allograft. Survival time for the acetabular cup as determined by Kaplan-Meier analysis was 153 months (95% confidence interval; range, 136-169 months). Cup failure was associated with more operative procedures performed before revision surgery (mean, 3.2 procedures), and failure to restore the vertical center of hip rotation to within 12 to 14 mm of the predicted value. The acetabular abduction angle was not a predictor for failure. The current study shows that good results can be achieved with structural acetabular allograft reconstruction with mid-term to long-term implant survival (cup aseptic survival, 80.4% and allograft re-construction survival, 94.1%), especially if there is restoration of near normal hip biomechanics.