Combining Anterior Talofibular Ligament Ultrasonography With Anterior Drawer Displacement Refines Stratification of Chronic Ankle Instability.

Abstract

Chronic ankle instability (CAI) is commonly defined using symptom-based criteria, but these do not explicitly incorporate structural instability after lateral ankle sprain. Whether ATFL findings and anterior displacement reflect symptoms and function remains unclear. This study examined the relationships among ATFL ultrasonography findings, anterior ankle displacement, perceived ankle instability, and self-reported function. This cross-sectional study included 187 participants classified as healthy, coper, or CAI using International Ankle Consortium criteria and the Cumberland Ankle Instability Tool (CAIT). ATFL ultrasonographic classification and instrumented anterior displacement were assessed by blinded examiners. Self-reported function was assessed using the Foot and Ankle Ability Measure (FAAM) in a subsample. Five groups defined by symptom classification and ATFL ultrasonographic classification were compared. Median anterior ankle displacement was 5.25, 5.63, 7.49, 6.14, and 9.02 mm in the healthy-ATFL normal, coper-ATFL normal, coper-ATFL abnormal, CAI-ATFL normal, and CAI-ATFL abnormal groups, respectively. Displacement was greater in the coper-ATFL abnormal and CAI-ATFL abnormal groups than in the healthy-ATFL normal and coper-ATFL normal groups (all p ≤ 0.004). The CAI-ATFL abnormal group also showed greater displacement than the CAI-ATFL normal group (p = 0.012). CAIT scores did not differ between CAI subgroups. In the FAAM subsample, the CAI-ATFL abnormal group had lower scores than several comparison groups. Section Specialty Area: Section IV: Sports Medicine & Orthopaedics. Investigation performed: Hokkaido Chitose College of Rehabilitation. ATFL ultrasonography stratified anterior ankle displacement within symptom-defined coper and CAI groups, whereas symptom-defined classification and self-reported function did not consistently reflect structural and mechanical findings. Structural assessment may refine phenotypic stratification in CAI research.