Revision Surgery for Metal Component Failure in Total Ankle Arthroplasty

BACKGROUND: Metal component failure in total ankle arthroplasty (TAA) is difficult to treat. Traditionally, conversion to an arthrodesis has been advocated. Revision TAA surgery has become more common with availability of revision implants and refinement of bone-conserving primary implants. The goal of this study was to analyze the clinical results and patient-reported outcomes for patients undergoing revision total ankle arthroplasty. METHODS: We retrospectively reviewed prospectively collected data on 52 patients with a mean age of 63.5 ± 9.6 years who had developed loosening or collapse of major metal components following primary TAA. These patients were compared to a case-matched control group of 52 primary TAAs performed at the host institution with a minimum of 2 years’ follow-up. Cases of isolated polyethylene exchange, infection, or extra-articular realignment procedures were excluded. The American Orthopaedic Foot & Ankle Society (AOFAS) hindfoot score, Short Form 36 (SF-36), Short Musculoskeletal Function Assessment (SMFA), and pain scores were prospectively collected. Clinical data was collected through review of the electronic medical record to identify reasons for clinical failure, where clinical failure was defined as second revision or conversion to arthrodesis or amputation. RESULTS: The identified causes of failure of primary TAA were aseptic loosening of both components (42%), talar component subsidence/loosening (36%), coronal talar subluxation (12%), tibial loosening (8%), and talar malrotation (2%). Thirty-one patients (59.5%) underwent revision of all components, 20 (38.5%) just the talar and polyethylene components, and one (2%) the tibial and polyethylene components. The average time to revision was 5.5 years ± 5.4 with a follow-up of 3.1 years ± 1.5 after revision. Eleven (21.2%) revision arthroplasties required further surgery: 6 required conversion to arthrodesis and 5 required second revision TAA. Pain scores, SF-36 scores, SMFA scores, and AOFAS Hindfoot scores all improved after revision surgery but never reached the same degree of improvement seen after primary TAA. CONCLUSIONS: Clinical and patient-reported outcomes of revision ankle arthroplasty after metal component failure significantly improved after surgery, although the recovery time was longer. In this series, 21.2% of revision TAAs required a second revision TAA or arthrodesis surgery. Various prostheses performed similarly when used for revision surgery. Revision TAA can offer significant improvements postoperatively. LEVEL OF EVIDENCE: Level III, therapeutic.