PROMs Behavior and Survivorship of Total Ankle Replacement Revisions: A Comprehensive Cohort Study

Research Type: Level 2 - Prospective comparative study, Meta-analysis of Level 2 studies or Level 1 studies with inconsistent results Introduction/Purpose: Total ankle replacement (TAR) has been increasing in frequency in recent years. As the number of primary TARs grows, the revision rate is also expected to rise. However, the behavior of patient-reported outcome measures (PROMs) and the survivorship of TAR-to-TAR revisions remain poorly understood. Methods: A prospective cohort study was conducted, including all TAR in our registry. Patients who underwent a TAR revision with metallic component replacement were included, while those undergoing revision via amputation or arthrodesis and those who withdrew from follow-up were excluded. Demographic characteristics were compared between revised and non-revised groups. The Ankle Osteoarthritis Scale (AOS) was assessed for distribution using the Shapiro-Wilk test. The Mann-Whitney U test compared AOS between revised and non-revised patients (baseline vs. 1–2 years post-revision or post primary replacement, respectively). The Wilcoxon test for paired samples assessed changes in AOS at baseline, pre-revision, and 1–2 years post-revision within the revised group. Kaplan-Meier analysis estimated survivorship of revised TARs. Results: Among 631 TAR procedures, 48 were revised (20 Agility, 13 Hintegra, 4 InBone II, 1 Infinity, 7 Mobility, 1 STAR, 2 Zimmer), with 43 undergoing TAR-to-TAR revision. Revised patients were significantly younger (p < 0.01) with no differences in diabetes, smoking, or BMI; no other factors were linked to revision risk. At baseline, revised patients had markedly worse AOS than non-revised patients (p < 0.01). In revised patients, AOS improved significantly from baseline to pre-revision (p < 0.01) and further at 1–2 years post-revision(p < 0.01); however, the change from pre- to post-revision was not significant (p=0.30). Nonetheless, at 1–2 years post-revision, their AOS remained significantly worse than non-revised controls (p < 0.01). The mean follow-up duration was 11.26±5.78 years. Overall, Kaplan-Meier analysis revealed a 10-year survivorship of 58.9%, declining to 51.1% at 13 years. Conclusion: TAR-to-TAR revisions demonstrate a 10-year survivorship of 58.9%, which decreases further over time. Patients requiring revision showed worse AOS at baseline, suggesting higher levels of pain and functional limitation even before revision. Although AOS scores improved both before and after revision, they remained inferior compared to non-revised patients. These findings indicate that revision TAR can reduce pain and enhance function but does not fully restore patients to the level of those who never required revision. Continued research is necessary to optimize surgical techniques, implant choices, and patient selection criteria, aiming to improve long-term functional outcomes following revision TAR.