Ultrasound-based assessment of talar cartilage in individuals with chronic ankle instability: a systematic review

PURPOSE: To systematically synthesize ultrasound (US) evidence on talar cartilage morphology and load-induced deformation in individuals with chronic ankle instability (CAI), and to map methodological approaches (acquisition, outcome definitions, loading paradigms, and normalization) to inform protocol standardization. METHODS: PubMed, Web of Science, and EBSCO were searched (March 31, 2025). Eligible studies reported quantitative US-derived talar cartilage morphology (e.g., thickness, cross-sectional area [CSA]) and/or deformation following standardized loading in CAI and comparison groups. Due to heterogeneity in imaging protocols, loading tasks, and outcome definitions, findings were synthesized narratively and organized by outcome domain. RESULTS: Across available cohorts, load-induced deformation was the most consistently differentiating signal: CAI groups generally demonstrated greater deformation than controls, with more frequent regional effects at the medial talar dome. Evidence for baseline (unloaded) morphological differences was mixed, with some studies reporting no group differences and others reporting larger CSA in CAI. Associations between deformation and neuromechanical measures (e.g., inversion laxity, postural control, hop biomechanics, ground reaction forces) were reported but were protocol- and cohort-dependent. CONCLUSIONS: Current evidence, limited by few unique cohorts, partial non-independence across publications, and heterogeneous acquisition/loading/normalization procedures, suggests that B-mode US can quantify talar cartilage morphology and detect load-induced deformation differences in CAI in research settings. Talar cartilage ultrasonography should be considered investigational until standardized acquisition and analysis procedures and longitudinal validity are established. Key Points • Ultrasound can quantify talar cartilage morphology and load-induced deformation in individuals with chronic ankle instability. • Load-induced talar cartilage deformation appears to be the most consistent ultrasound-derived feature differentiating chronic ankle instability from healthy controls. • Evidence for baseline talar cartilage morphology differences is mixed, likely reflecting heterogeneity in cohorts and imaging/loading protocols. • Standardized acquisition, loading, and analysis methods, along with independent longitudinal validation, are needed before clinical translation.