Short-Term Risk of Subtalar Joint Arthritis After Stemmed Total Ankle Replacement.

Abstract

Ankle osteoarthritis (OA) can significantly impact mobility and quality of life. Total ankle replacement (TAR) has emerged as an alternative to ankle arthrodesis due to its potential for preserving natural joint kinematics. However, it remains unclear if this maintained motion also limits progression of adjacent joint degeneration. This study aims to evaluate the influence of stemmed implants on the progression of subtalar (STJ) osteoarthritis and delayed secondary STJ fusion. A retrospective analysis was performed on 115 patients who underwent primary Stryker Inbone® fixed-bearing, stemmed TAR between December 2018 and February 2024. Patients with pre-existing STJ fusion or less than one year of postoperative follow-up were excluded. The final cohort of 72 patients, with a mean follow-up of 2.43 years, underwent radiographic and clinical evaluation of STJ osteoarthritis. The Kellgren-Lawrence Score (KLS) was utilized to assess changes in STJ arthritis preoperatively and postoperatively. Radiographic progression of STJ arthritis was seen in 6.94% of patients, with only 1.39% requiring secondary STJ fusion. Only one patient underwent fusion due to avascular necrosis of the talus, resulting in a case of nonunion. Seven patients reported postoperative STJ pain, despite stable radiographic findings, each of which was managed conservatively without additional surgical intervention. These findings support and add to the limited body of literature on the use of stemmed ankle implants in limiting progressive adjacent joint arthritis to the STJ in the short term.