Pre-op Ankle Dorsiflexion: A Predictor of Total Ankle Arthroplasty (TAA) Outcomes?

by Vince Vacketta, DPM

Can surgeons predict which patients will remain stiff after TAA, and can adjunctive soft-tissue procedures meaningfully change that? In a recent retrospective review of 175 primary TAAs performed by a single surgeon from 2013–2023, Thomas et al. addressed this question by measuring postoperative motion on weight-bearing radiographs, defining dorsiflexion (DF) under 20° as limited. The mean follow-up was 3.3 years. 

Key finding

• Postoperative DF was limited in 63% of patients.

• Preoperative clinical DF was the only independent predictor of postoperative DF.

• Post-traumatic osteoarthritis correlated with decreased postoperative DF, but it was not an independent predictor on multivariable analysis.

• Importantly, gastrocnemius recession and Achilles lengthening were not associated with improved final DF.

• Patients with 20° or more DF had substantially better FAAM-ADL scores than those with less: 86.9 vs. 70.0.

  
  

Why it matters

These findings may have implications for how surgeons counsel and select patients:

• TAA may preserve motion, but it doesn't necessarily create it. 

• Patients with limited preoperative DF appear likely to remain relatively stiff afterward. 

• Adjunctive posterior muscle group lengthening did not overcome preoperative DF limitations.

• Preoperative ROM may therefore be particularly useful for setting realistic expectations about postoperative motion.