Objective: The objective of the study was to determine whether distal tibiofibular and talar morphological features are associated with the severity of anterior talofibular ligament (ATFL) injury after acute lateral ankle sprain.
Materials and
Methods: This retrospective observational study included 280 adults who underwent magnetic resonance imaging (MRI) for acute lateral ankle sprain between January 2018 and December 2024. ATFL injury was classified according to the four-level Schneck system (grade 0–III); using a grade-stratified design, 70 patients were selected at random within each grade. Eighteen radiographic and MRI-based morphological parameters were assessed by blinded observers. Between-grade comparisons used univariate tests with false discovery rate correction. Independent associations with increasing ATFL injury grade were evaluated using ordinal logistic regression.

Results: Nine of 18 morphological parameters differed significantly across injury grades after false discovery rate correction. In the multivariable ordinal model, a smaller talar radius (odds ratio [OR]=0.761/mm, 95% confidence interval [CI]: 0.696–0.832), greater talar height (OR=1.095/mm, 95% CI: 1.047–1.145), higher distal tibial lateral angle (OR=1.112/degree, 95% CI: 1.036–1.195), longer anterior tubercle (OR=1.183/mm, 95% CI: 1.055–1.327), and greater talar dome–distal fibula distance (OR=1.428/mm, 95% CI: 1.124–1.811) were independently associated with higher injury grades. I-type fibular notch morphology was associated with lower odds of a higher grade than C-type morphology (OR=0.295, 95% CI: 0.154–0.564). The model had a Nagelkerke pseudo-R² of 0.286.

Conclusion: Talocrural osseous morphology is independently associated with acute ATFL injury severity. These routinely measurable features may contribute to anatomy-informed risk assessment, but the findings are cross-sectional and hypothesis-generating and should not be interpreted as individual-level predictors.