Abstract
Research Type:
Level 3 - Retrospective cohort study, Case-control study, Meta-analysis of Level 3 studies
Introduction/Purpose:
The Infinity with Adaptis Total Ankle System (Stryker, Mahwah, NJ) is a low-profile, fixed-bearing implant that became available for use in October 2019. The 3D-printed porous metal surface of the Adaptis technology is intended to improve implant stability and better facilitate osseous integration, although this has not been clinically demonstrated yet. The aim of this study was to compare Infinity total ankle replacement (TAR) with and without Adaptis technology to determine, if any, differences in clinical and radiographic outcomes at minimum 2-year follow-up. We hypothesized that patients who underwent TAR with Infinity with Adaptis will have less radiographic lucency around the implant compared to those who underwent TAR with Legacy Infinity.
Methods:
A retrospective review of patients who underwent primary total ankle arthroplasty (TAA) with Infinity with and without Adaptis technology between November 2019 and December 2023 at a single institution was completed. Chart review was performed to identify complications, reoperations, and revision procedures. Pre-operative and post-operative radiographs were measured to assess tibiotalar alignment and identify periprosthetic lucencies, cysts, or subsidence. Patient-Reported Outcomes Measurement Information System (PROMIS) scores were collected pre-operatively and at 1- and 2-years post-operatively to assess clinical outcomes. Of the 339 ankles that underwent a primary TAR, 124 had the Infinity with Adaptis and 215 without Adaptis.
Results:
No significant differences were found between groups in demographic variables and global lucency at 1- and 2–years post-operatively. Revision rates were higher in the Adaptis Infinity group compared to the Legacy Infinity group (10% vs. 2%; p=0.035). Post-operative coronal tibial alignment, coronal tibiotalar offset, and sagittal tibiotalar alignment were lower in the Adaptis group. No significant differences were found between groups in terms of physical function or pain intensity at 1- and 2-years post-operatively. Pain interference at 1-year was not statistically significant between groups, but the Legacy Infinity group was statistically lower at 2-years (49.2 vs. 52.4; p=0.044). While both groups saw significant improvements over time, the Infinity Legacy demonstrated statistically significant improvements in global physical health, global mental health, and depression at 2-year follow-up.
Conclusion:
Patients who underwent Infinity TAR with Adaptis as compared to without Adaptis demonstrate no statistically significant difference in global lucency rates at 1- and 2-years postoperatively. While some findings were found to be statistically significant, they may not be clinically significant in these domains. Further research is needed in the long term to determine if there is a benefit to Adaptis technology.