The INFINITY Total Ankle Prosthesis: Outcomes at Short Term Follow-up

CATEGORY: Ankle Arthritis; Ankle; Other INTRODUCTION/PURPOSE: The INFINITY total ankle prosthesis remains the most widely used 4th generation total ankle arthroplasty (TAA) system in the United States. The purpose of the present study was to assess outcomes for the INFINITY prosthesis at short-term follow-up. METHODS: All patients who underwent primary TAA with INFINITY between August 2015 and June 2018 at a single institution and who were at least 1 year postoperative were included. A total of 55 ankles with a mean follow up 22 (range, 12-43) months met the criteria. Weightbearing radiographs were assessed using coronal and sagittal alignment parameters preoperatively, at 6- 8 weeks postoperatively, and at the most recent follow-up. Medical records and charts were reviewed and revisions, reoperations, and complications were classified according to the criteria established by Vander Griend et al. and Glazebrook at el., respectively. RESULTS: Overall survivorship for the INFINITY prosthesis was 98.2%. Coronal and sagittal tibiotalar alignment improved after surgery (p<.001, p=0.09), and was maintained during the latest follow-up (p=0.62, p=0.47). One ankle (1.8%) required early component revision; while 5 (9.1%) required non-implant related revision. Postoperative periprosthetic lucency’s were observed in nineteen ankles (34.5%); most of which were non-progressive (17 ankles, 89.5%). Thirteen complications (3 high grade, 3 intermediate, and 7 low) in 11 ankles (20%) were recorded according to the Glazebrook classification system. CONCLUSION: INFINITY survivorship was 98.2% at a mean of 1.8 years of follow-up, with only 1 ankle requiring prosthetic revision. Additional studies with longer follow-up are warranted for 4th generation TAA prostheses.