A Systematic Review of Outcomes of Total Ankle Arthroplasty with INBONE II

Abstract

Category: Ankle Arthritis; Ankle Introduction/Purpose: The INBONE II is a fixed-bearing implant with a stemmed tibial component commonly used for total ankle arthroplasty (TAA). Despite its frequent use and previously reported outcomes within individual clinical studies, no study has systematically reviewed outcomes of TAA with this implant. The purpose of this study was to perform a systematic review of the literature and report on outcomes of TAA with the INBONE II. Methods: A systematic review of the literature was performed according to the Preferred Reporting Items for Systematic Review and Meta-analyses (PRISMA) guidelines. Databases searched included PubMed, Google Scholar, SCOPUS and CINAHL from database date of inception through February 28th, 2023. Clinical studies of INBONE II outcomes in peer reviewed journals were included. Outcomes included were survivorship, patient reported outcome measures (PROMs), and complications. Outcome results were compiled using weighted averages when possible. This review of 26 articles included 808 patients with 667 primary TAA and 141 revision TAA. Results: Survivorship, with failure defined as metal component revision, was 97.8% at an average follow-up of 49 months (range, 14-85.4 months) and 94.2% at an average follow-up of 25.7 months (range, 9.1-47.5) months for primary and revision TAA respectively. Complication rates for primary TAA included: 3.8% intra-operative fractures, 2.5% post-operative fractures, 1.8% deep infection, 8.0% wound complications, 1.6% rate of poly exchange, and 1.6% nerve injuries. Revision TAA complication rates included: 12.3% intra-operative fractures, 6.9% wound complications, 3.3% deep infections, and a 5.5% incidence of nerve injury. Average PROMs for primary TAA included: AOFAS American Orthopaedic Foot and Ankle Society (AOFAS) hindfoot score improved 41 points, visual analog scale (VAS) scores decreased 5.9, and patient satisfaction of 92.6%. Revision TAA PROMs were not consistently reported. Conclusion: This study is the largest compilation of INBONE II outcomes and survivorship. Primary and revision TAA with the INBONE II results in satisfactory improvement in PROMs and low complication rates. The overall survivorship is 97.8% and 94.2% at an average follow-up of 49 months (range, 14-85.4 months) and 25.7 months (range, 9.1-47.5) for primary and revision total ankle arthroplasty respectively. These findings support continued use of this implant in primary and revision TAA.