Ultrasonographic Anterior Talofibular Ligament Thickness Does Not Predict Functional Outcomes After Acute Lateral Ankle Sprain
ABSTRACT Background Ultrasonography is commonly used to evaluate ligament injuries following acute lateral ankle sprain. However, the clinical significance of structural changes in ligament thickness during the healing process remains unclear. This study aimed to evaluate whether changes in anterior talofibular ligament (ATFL) thickness are associated with functional clinical outcomes. Methods This study was a retrospective analysis of prospectively collected cohort data involving 32 patients with acute lateral ankle sprain enrolled between January 2024 and March 2025. All patients underwent conservative treatment and were followed for up to 12 weeks after injury. Patients were excluded if they had a history of prior ankle sprain, fracture, deformity, previous surgery involving the foot or ankle, or avulsion‐type ATFL injury. Standardized ultrasound examinations were performed at baseline and at 3, 6, and 12 weeks after injury. ATFL thickness was measured bilaterally at the ligament midpoint, and an injured‐to‐healthy thickness ratio was calculated. Functional outcomes were assessed at 12 weeks using the visual analog scale (VAS), American Orthopedic Foot and Ankle Society (AOFAS) score, and Cumberland Ankle Instability Tool (CAIT). Temporal changes were analyzed using repeated‐measures ANOVA, and correlations were assessed using Pearson correlation analysis. Results The ATFL thickness ratio decreased significantly over time (p < 0.05), suggesting progressive structural remodeling during healing. Clinical outcomes improved significantly (all p < 0.001). However, no significant associations were detected between the ATFL thickness ratio and functional outcome measures at any time point (all p > 0.05). Conclusions Although serial ultrasonography demonstrated progressive morphological remodeling of the ATFL following acute lateral ankle sprain, the present study did not detect a significant association between the ATFL thickness ratio and short‐term functional outcomes. These findings suggest that ultrasonographic thickness alone may not fully reflect clinical recovery.