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Bone-grafting for acetabular deficiency during primary and revision total hip arthroplasty. A radiographic and
J L Knight1, K Fujii, R Atwater
1Department of Orthopaedic Surgery, Group Health Cooperative of Puget Sound, Redmond, WA 98052.
Insights
Acetabular bone-grafting in total hip arthroplasty (THA) is complex. Cup loosening is linked to specific defect types, graft material, and initial cup positioning, highlighting the need for careful technique.
Area of Science:
- Orthopaedic Surgery
- Biomaterials Science
Background:
- Acetabular bone-grafting is a debated technique in total hip arthroplasty (THA) for acetabular augmentation.
- Factors influencing acetabular cup loosening after bone-grafting require clarification.
Purpose of the Study:
- To identify factors associated with acetabular cup loosening in patients undergoing THA with bone-grafting.
- To evaluate the long-term outcomes of acetabular bone-grafting in THA.
Main Methods:
- Retrospective review of 74 THA cases with acetabular bone-grafting and minimum 24-month follow-up.
- Radiographic analysis including hip center and cup abduction migration measurements.
- Kaplan-Meier log-rank analysis for survivorship and complication assessment.
Main Results:
- Graft union was observed in all cases.
- Clinician assessment revealed 12% definitely loose cups; computer analysis detected loosening earlier and more frequently.
- Cup loosening correlated with American Academy of Orthopaedic Surgeons type III defects, allograft use, and initial cup abduction ≥50 degrees.
Conclusions:
- Acetabular bone-grafting is technically demanding and associated with specific risk factors for cup loosening.
- Grafting should be reserved for cases where alternative reconstructions are unlikely to provide durable results.
- Careful surgical technique and patient selection are crucial for successful outcomes.
Abstract:
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.