Changes in ankle muscle strength following arthroplasty: A systematic review

Muscle strength assessment is key after Total ankle arthroplasty (TAA) or Ankle arthrodesis (AA) to guide recovery and improve function. However, variability in protocols, timing, and reported outcomes limits standardization and hinders the development of effective, personalized rehabilitation strategies. This systematic review aimed to (I) determine strength levels before and after surgical procedures (II) identify the movements, types of contraction, velocities, and positions most used for measuring strength in patients with TAA and AA, and (III) establish the most used methodologies for the evaluation of patients with TAA and AA.

A comprehensive search of four electronic databases identified 214 studies, of which 4 met the inclusion criteria. Data extraction and analysis followed PRISMA guidelines, with methodological quality evaluated using the Downs & Black Checklist Tool.

Four studies were included, with sample sizes ranging from 10 to 38 participants who underwent total ankle arthroplasty or arthrodesis. Most strength assessments were isometric, conducted in a seated position, and focused on dorsiflexion and plantarflexion, demonstrating high reliability (ICC between 0.78 and 0.99). Plantarflexion torque values in the operated ankles ranged from 15.7 to 26 Nm, while dorsiflexion values ranged from 12 to 23.1 Nm. Inversion and eversion were assessed less frequently and showed greater variability. Isokinetic measurements revealed a significant reduction in strength compared to healthy controls, with plantarflexion torque reaching only 0.22 to 0.26 Nm/kg.

Isometric protocols are commonly used to evaluate ankle strength after TAA or AA, especially in seated positions with knee flexion.