Bone Morphogenetic Protein Augmentation of Large Acetabular Defects in Revision Total Hip Arthroplasty: A Viable Option for Massive Bone Loss

Background: Large acetabular defects in revision total hip arthroplasty (THA) are challenging surgical problems.While bone morphogenetic proteins (BMPs) have shown promise in enhancing bone growth, the long-term outcomes of revision THA with BMP-2 augmentation for large acetabular defects are unknown.Methods: A single-surgeon retrospective cohort study of consecutive patients who received BMP-2 augmentation during revision THA was conducted.Acetabular defects were graded using the Paprosky classification, heterotopic ossification was quantified using the Brooker classification, and bone consolidation was assessed radiographically.Postoperative complications, subsequent reoperations, and Oxford Hip Scores were recorded.Kaplan-Meier survival estimates were generated with allcause reoperation as the endpoint.Results: Fifteen patients (18 hips) with an average age of 64.6 16.1 years and a mean follow-up of 76.3 43.1 months were included.Patients underwent an average of 1.9 1.3 surgeries prior to revision.There were 10 hips with Paprosky 3B defects, 3 with 3A defects, 3 with 2C defects, and 2 with 2B defects.Eleven hips had pelvic discontinuity.Postoperatively, 15 hips (83.3%) showed radiographic evidence of >50% bone consolidation.With all-cause reoperation as the primary endpoint, 6-and 10-year survivorship was 90.0% (95% CI: 47.3%-100.0%)and 70.0%(95% CI: 32.9%-89.2%),respectively.Regarding acetabular loosening, both 6-and 10-year survivorship was 90.0% (95% CI: 47.3%-98.5%).Mean Oxford Hip Score was 34.8 9.2 at final follow-up.Discussion: BMP-2 augmentation is a viable treatment option in revision THA when massive bone loss is encountered.However, further research is necessary to elucidate the safety and efficacy of BMP-2 adjuvant therapy in the setting of revision THA.