The Journal of Arthroplasty Vol. 13 No. 1 1998 2- to 10-Year Follow-up Study of Acetabular Revisions Using Allograft Bone to Repair Bone Defects Sinan Avci, MD, Nicholas Connors, MD, and William Petty, MD Abstract: The failure rates of revision of acetabular components have been high; however, long-term success has been reported with the use of particulate allografts or autografts with large-diameter prosthetic cups to correct bone deficiencies when host-cup contact is at least 30% to 50%. The purpose of this study was to review 2- to 10-year follow-up data on complex acetabular revisions in which contact between allograft bone and the prosthetic cup was at least 50%. In the 47 hips monitored clinically and radiographically for a mean of 5 years, results were classified as excellent in 37%, good in 26%, fair in 17%, and poor in 19%. The mean Harris hip score was 82.5 (range, 39-I00). The prosthetic cups migrated in 3 hips, but 2 stabilized within 1 year. Three cups had complete radiolucent lines without migra- tion; the lines did not correlate with location of the allografts. Although bone ingrowth into porous surfaces from allografts is debatable, the results of the study show that massive allograft reconstruction of the acetabulum can provide both immediate and long-term stability of the prosthetic cup and restore bone stock. Key words: acetabulum, prosthesis, failure, revision, allograft, hip. Revision of acetabular components continues to be a challenging problem. Ideally, surgery should cor- rect the bone deficiency and provide both immedi- ate and long-term stability of the component in its appropriate anatomic position. Surgeons who per- form these procedures generally discover there is considerable variation in the extent of bone defects from patient to patient. Attempts to revise acetabula with cemented components have been largely un- successful and rates of early failure have been high, probably because of inadequate cement interdigita- tion into bone. The use of modern cementing techniques has not improved the results [I-4]. Efforts to restore the bone stock by bone-grafting From the Department of Orthopaedics, University of FIorida Collegeof Medicine, Gainesville, Florida. Reprint requests: William Petty, MD, Department of Orthopae- dics, Box I00246, University of Florida College of Medicine, Gainesville, FL 32610-0246. Copyright © 1998 Churchill Livingstone. 0883-5403/1301-000955.00t0 and use of bipolar implants have also resulted in failure due to mi~ation of components and pain ]5,6]. Many investigators have restored bone in the ac- etabulum at the time of primary surgery or revision arthroplasty, with either allografls or autografts, with good short-term results, Kwong et al., however, have reported a sudden rise in failure rate after 5 years because of graft collapse. They attributed the failures to normal biologic changes in the allografts, which weaken during the revascularization process [7]. The use of particulate allografts or autografts with large-diameter prosthetic cups to correct bone defi- ciencies has also been reported [8-I 0]. These inves- tigators have reported that biologic ingrowth and long-term success can be achieved if the host-cup contact is at least 30% to 50%. The purpose of our retrospective study was to review data from our 2- to 10-year follow-up evaluation of complex acetabu- lar revisions in which the contact between allograft bone and the prosthetic cup was at least 50%. 61