Long-term Results for Minor Column Allografts in Revision Hip Arthroplasty

Background While acetabular structural allografts provide an important alternative for reconstructions, concerns remain with long-term graft resorption, collapse, and failure. Midterm studies of minor column (shelf) allograft suggest reasonable survival but long-term survival is unknown. Questions/purposes We therefore assessed long-term graft/cup survivorship, functional scores, radiographic resorption, and complications associated with minor column allograft. Methods We retrospectively reviewed 74 patients (85 hips) with a mean age of 54 years (range, 28-83 years) undergoing acetabular cup revision using a minor column allograft. A minor column allograft was used in uncontained acetabular bone defects sized between 30% and 50% of the acetabulum. Graft failure was considered to occur when the graft required revision with another graft, metal augment, reconstruction cage, or excision arthroplasty. The minimum followup was 5 years (mean, 16 years; range, 5.3-25 years). Results Twenty-three patients (27 hips) had rerevision for all causes at a mean time to rerevision of 6.9 years (range, 0.1-23). Fifteen grafts failed at a mean time-to-rerevision of 6.1 years (range, 0.5-23.2). The 15- and 20-year Kaplan-Meier survivorships were 61% and 55% for cups and 78% for grafts with rerevision for all causes as end point. With rerevision for aseptic loosening as end point, survivorships were 67% and 61% for cups and 81% for grafts. The mean modified Harris hip scores were 41 (range, 20-60) preoperatively, 73 (range, 40-95) at 1 year postoperatively and 73 (range, 26-93) at last followup. Conclusion The data may provide a long-term benchmark by which future treatments for Type III defects can be measured.