Abstract
Introduction: Non-union following hindfoot arthrodesis remains a significant risk in foot and ankle surgery. In the reported series of revision hindfoot arthrodeses non-union rates range from 9 to 25% with approximately half these patients going on to a transtibial amputation. Bone morphogenic proteins (BMP) are a group of naturally occurring proteins with strong osteoinductive properties, which have shown promise in the treatment of fracture non-unions and primary hindfoot arthrodesis surgery. This article reports our experiences with rhBMP-7 as an adjunct to revision arthrodesis surgery in this high-risk subset of patients.
Methods: Eight patients with at least one previous non-union and two or more risk factors for non-union and one patient on steroids with a failed total ankle replacement were prospectively recruited to the study. A revision arthrodesis procedure with internal fixation was performed according to the senior author’s revision protocol with the addition of 3.5mg rhBMP-7 combined with 40mls of bone marrow aspirate. Bone graft was used only if there was structural bone loss. Outcome was assessed clinically and radiologically.
Results: Follow-up ranges from 3 to 22 months (average 13 months). Clinically 8 of the 9 patients had a pain free, stable arthrodesis. Seven patients were satisfied with their functional improvement and pain relief. Radiologically two patients have united, six patients have partial unions with ongoing progression towards union and one patient has a painless non-union. There was one wound infection and one malunion. No complications related to rhBMP-7 were experienced.
Conclusion: Revision arthrodesis with adjuvant rhBMP-7 has led to limb salvage in this group of high-risk patients. However, rhBMP-7 is not a panacea for achieving union and does not replace meticulous surgical planning and technique. Achieving bony union in this subset of patients remains a high risk and protracted process. No concerns about the short-term safety of rhBMP-7 were raised.
Correspondence should be addressed to A.H.N. Robinson, BOX 37, Department of Orthopaedics, Addenbrooke’s Hospital, Cambridge University Hospitals NHS Trust, Hills Road, Cambridge. CB2 0QQ, England.
