Bone morphogenic protein-2 use in revision total hip arthroplasty with acetabular defects

The restoration of acetabular bone stock during revision hip arthroplasty remains a challenge. There have been no clinical series reporting the efficacy of bone morphogenic protein-2 (rhBMP-2) in the revision hip setting.

We retrospectively reviewed the radiographs and records of 15 patients who received rhBMP-2 mixed with allograft bone chips (+BMP), and 14 who received allograft bone chips alone (-BMP) for their acetabular defect during revision total hip arthroplasty with a mean two-year follow up. Radiographs were evaluated for acetabular defect size, superior cup migration, and changes in the lateral cup abduction angle. Modified Harris hip scores were used for evaluation of clinical outcomes.

Patients in the +BMP group compared to the -BMP group had significantly larger amounts of cancellous bone chips used (72.1 ± 35.5 cc vs. 38.6 ± 14.1 cc; p = 0.003). Mean rhBMP-2 used per case was 7.4 ± 3.1 mg in the +BMP group. Three patients in the -BMP group had cup migration which was not observed in the +BMP group. Mean Harris hip scores (HHS) improved post-operatively in both groups (40.1 ± 20.9 to 71.9 ± 19, p < .0001). No local adverse reaction was noted in the +BMP group.

rhBMP-2 had modest clinical benefit in the setting of revision THA. Cost of this synthetic biologic versus the added clinical benefit should be carefully considered when being used in the revision hip setting.