Risk Factors for Early Failure of 4th Generation Total Ankle Arthroplasty Prostheses

CATEGORY: Ankle Arthritis; Ankle; Other INTRODUCTION/PURPOSE: A number of two-component, 4th generation total ankle arthroplasty (TAA) prostheses have been introduced to the market in the past few years, as the popularity and indications for TAA have continued to expand. The purpose of the present study was to identify independent risk factors for the early failure of 4th generation TAA prostheses. METHODS: A total of 97 ankles underwent TAA with a 4th generation prostheses (INFINITY, CADENCE) between August 2015 and June 2018 at a single institution and were at least 6 months postoperative (mean 18.3 months, range 6-43). The primary outcome assessed was the need for revision surgery, defined as removal of 1 or both metal components for any reason, excluding infection. Baseline patient demographics, characteristics, radiographic alignment parameters, and distal tibia cortical bone thickness (CBT) were assessed. Revisions, reoperations, and complications were classified according to the criteria established by Vander Griend et al. and Glazebrook et el., respectively. Univariate and multivariate analyses were performed. RESULTS: Three ankles (3.1%) underwent revision surgery for aseptic loosening at a mean of 24.3 (range, 16-31) months; all had a CBT <4mm. Independent predictors for reoperation were a CBT < 4mm, the presence of diabetes, and ipsilateral hindfoot fusion (p=0.04). No associations were identified for purported risk factors (age, BMI, and coronal deformity). CONCLUSION: The present study is the first to suggest a potential relationship between CBT of the distal tibia and TAA failure. Additional studies are warranted to better understand the role of bone density in TAA survivorship.