Evidence for Graft Materials Used in Hindfoot and Ankle Arthrodesis: A Systematic Literature Review

Abstract

Category: Hindfoot; Ankle Introduction/Purpose: There is a wide range of graft materials available to supplement hindfoot and ankle arthrodesis procedures. These include autograft, allografts, and bone graft substitutes. While these various materials are commonly used, the level of evidence to support each has not been widely explored. The purpose of this study was to conduct a systematic literature review to evaluate the level of evidence that exists for each of these materials to inform clinical decision making towards optimal patient outcomes. Methods: A systematic literature review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement. The search was conducted using the Embase, MEDLINE, and Cochrane Controlled Register of Trials databases in May 2019 for studies published in English since January 1, 2009. The review included all studies published with patients who were at least 18 years of age needing graft material for hindfoot or ankle arthrodesis. Two independent reviewers reviewed all abstracts for inclusion. Disagreements were resolved by a third reviewer for consensus. Results: The search returned 3,547 records, of which 35 were included. Autograft and allograft had the largest number of studies, most of which were retrospective case series. Recombinant human platelet-derived growth factor BB with beta-tricalcium phosphate (rhPDGF-BB/β-TCP) and autograft were supported by the highest levels of evidence, each having four randomized controlled trials (RCTs). B2A was the only other material in an RCT, but with only24 subjects. Allograft and off-label use of recombinant human bone morphogenetic protein (rhBMP) were supported mainly by retrospective case series. Another assessment of quality was the endpoints. Fusion status was assessed by computed tomography (CT) and/or radiographs, with CT considered superior. Seventeen (17) studies used CT, but the definition of fusion varied from a high barrier of 'at least 50% osseous bridging' in 6 autograft, 5 rhPDGF-BB/β-TCP, 1 rhBMP, 1 demineralized bone matrix, and 1 B2A studies to a lower or undefined criteria in other studies. Conclusion: This literature review reveals the use of grafting materials is supported by a wide range of evidence quality. Most are supported by Level IV evidence, with the exceptions of autograft and rhPDGF-BB/β-TCP. Both are supported by multiple Level I studies. When looking at the methods for assessing fusion status, less than half of studies used CT. Of these, autograft and rhPDGF-BB/β-TCP both had at least 5 studies using CT while other materials had at most 1 study. Surgeons may wish to consider the availability of high-quality evidence, or the lack of, when selecting grafting materials.