The role of orthobiologics in foot and ankle surgery: Allogenic bone grafts and bone graft substitutes.

Orthobiologics are biological substances that are used therapeutically for their positive effects on healing skeletal and soft-tissue injuries. The array of orthobiological products currently available to the foot and ankle surgeon is wide, and includes bone allografts, bone substitutes, growth factors, and chondral scaffolds. Nonetheless, despite the surge in interest and usage of orthobiologics, there remains a relative paucity of research addressing their specific applications in foot and ankle surgery. In this review, we attempt to provide an overview of the literature on commonly available allogenic bone grafts and bone substitutes. There is Level II, III and IV evidence addressing allogenic bone grafts in primary arthrodesis and osteotomy procedures in foot and ankle surgery, which compares favourably with autogenic bone grafts in terms of fusion rates and clinical outcomes (often with fewer complications), and supports a Grade B recommendation for its use. Pertaining to bone substitutes, the multiplicity of products, coupled with a lack of large prospective clinical trials, makes firm recommendations difficult. Level II and IV studies of calcium phosphate and calcium sulphate products in displaced intra-articular calcaneal fractures have found favourable results in addressing bone voids, maintaining reduction and promoting union, meriting a Grade B recommendation. Evidence for TCP is limited to level IV studies reporting similarly good outcomes in intra-articular calcaneal fractures, warranting a Grade C recommendation. The use of demineralised bone matrix products in hindfoot and ankle fusions has been described in Level II and III studies, with favourable results in achieving fusion and good clinical outcomes, supporting a Grade B recommendation for these indications. Overall, despite the general lack of high-level evidence in foot and ankle surgery, allogenic bone grafts and bone substitutes continue to hold front-line roles in treating the bone defects encountered in trauma, tumour, and deformity correction surgery. However, more investigation is required before firm recommendations can be made.