Beta-tricalcium phosphate combined with native bone proteins (β-TCP - NBP): a novel bone graft substitute for ankle and hindfoot arthrodesis.

PURPOSE

The purpose of this prospective, multi-centre study was to assess the performance and safety of a combination of osteoconductive β-tricalcium phosphate and osteoinductive native bone proteins (β-TCP - NBP) used as alternative for autograft in ankle and hindfoot arthrodesis.

METHODS

Thirty-four patients enrolled underwent ankle or hindfoot arthrodesis with β-TCP - NBP and were evaluated radiographically, clinically, and functionally up to fifty-two weeks. The primary performance endpoint was fusion rate evaluated with CT at six months. Safety was assessed based on the severity and incidence of adverse events. Functional evaluation was performed using the American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot score and pain was recorded using the Visual Analogue Scale (VAS).

RESULTS

CT at 6 months showed that 85.3% had osseous bridging of the joint of ≥ 25%, 52.9% ≥50%, 8.8% <25% and 5.9% showed no bridging. The AOFAS score increased significantly from 60.4 ± 17.6 points at operation to 68.6 ± 17.2 points at six months and to 73.5 ± 17.7 points at 12 months. The group with fusion rate ≥25% showed significantly higher AOFAS score than that with fusion rate < 25% at 12 months. The mean VAS pain score at rest and during weight bearing decreased significantly (p < 0.0001) from operation to six and 12 months.

CONCLUSION

This study demonstrated that β-TCP - NBP is a valuable bone graft substitute for fusion of ankle and hindfoot due to debilitating osteoarthritis and offers an alternative for autograft.

LEVEL OF EVIDENCE

Level II.