Early Clinical, Radiographic, and Patient-Reported Outcomes of the Infinity With Adaptis Total Ankle System

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 aim of this study was to describe the early clinical and radiographic outcomes of the Infinity with Adaptis implant at minimum 2-year follow-up.

A retrospective review of 71 ankles that underwent primary total ankle arthroplasty (TAA) with Infinity with Adaptis implants between November 2019 and November 2021 at a single institution was completed. Chart review was performed to identify complications, reoperations, and revision procedures. Preoperative and postoperative radiographs were measured to assess tibiotalar alignment and identify periprosthetic lucencies, cysts, or subsidence. Patient-Reported Outcomes Measurement Information System (PROMIS) scores were collected preoperatively and at 1 and 2 years postoperatively to assess clinical outcomes.

At final follow-up (average 2.7 ± 0.6 years), 68 of the 71 ankles remained implanted (95.8%). Three ankles were revised within 1.5 years of the index procedure (1 for talar component loosening and 2 for infection). There were an additional 5 (7.0%) reoperations at an average of 16.0 (range: 1.1-37.1) months postoperatively. Patients demonstrated both clinically and statistically significant improvements in preoperative to 1-year postoperative PROMIS scores (P < .0001). There was no statistically significant improvement in scores from 1 to 2 years postoperatively. There was improvement in radiographic alignment from the preoperative to postoperative radiographs (P < .001), and tibial component lucency was observed in 20 of 71 without progressive global lucency during the study window.

Patients who underwent total ankle arthroplasty with the Infinity with Adaptis Total Ankle Replacement demonstrated significant improvements in radiographic and clinical outcomes at a minimum of 2-year follow-up with 95.8% (68/71) implant retention and a tibial lucency rate of 28.2% in this cohort. These observational findings warrant mid- to long-term surveillance to determine the clinical significance of early lucencies and the durability of this design's porous-surface osseointegration.