Bone-grafting for acetabular deficiency during primary and revision total hip arthroplasty. A radiographic and clinical analysis.

The use of bone-graft to augment the deficient acetabulum in primary and revision total hip arthroplasty (THA) is controversial. To identify factors affecting cup loosening in patients who received a bone-graft during THA, two orthopaedic surgeons retrospectively examined sequential radiographs. The surgeons also obtained independent computer measurements of hip center and cup abduction migration from preoperative, initial, and latest postoperative radiographs. Variables studied included host factors, graft factors, and technique factors. All conclusions were based on Kaplan-Meier log-rank analysis to account for differing lengths of follow-up periods among the cases. The authors report a series of 74 consecutive cases with a minimum 24-month follow-up period (mean, 40 months). All grafts appeared to unite. The clinicians found 80% stable cups, 8% possibly loose cups, and 12% (n = 9) definitely loose cups. In retrospect, technical errors were seen in six loose cups. Five revisions for loosening (6.7% of cases) were performed. Computer measurement found cup loosening in a higher percentage of cases than detected by the clinicians and did so an average of 18 months sooner. Acetabular cup loosening was associated with the American Academy of Orthopaedic Surgeons type III defects, use of allograft versus autograft, and initial cup abduction of 50 degrees or more. Kaplan-Meier survivorship analysis found 31% of cups radiographically loose and 15% revised at 5 years or more since surgery. Acetabular bone-grafting is technically demanding and should be employed when alternative reconstructions will not give a durable result.