Evaluation of the osseous morphology at ATFL attachments and its anatomic ligamentous features in chronic ankle instability using MRI.

Objective: This study aimed to evaluate the relationship between chronic ankle instability (CAI) and both the anatomical characteristics of the anterior talofibular ligament (ATFL) and the bony morphometry of its attachment sites on the fibula and talus using MRI.

Methods: A total of 94 patients were included in this retrospective study (44 with CAI, 50 controls). Morphometric parameters including ATFL length, width, thickness, and the ATFL/PTFL angle were measured, along with sagittal and coronal widths of the fibula and talus at ATFL attachment levels.

Results: The ATFL was significantly longer, thinner, and narrower in the CAI group compared to controls (p < 0.001). The ATFL/PTFL angle was also significantly greater in the CAI group (p = 0.007). However, no statistically significant differences were observed in the sagittal or coronal widths of the talus and fibula. ROC analysis revealed that ATFL length had the highest diagnostic performance (AUC = 0.881). Logistic regression identified increased ATFL/PTFL angle and decreased ATFL width and thickness as independent predictors of instability.

Conclusion: While the ligamentous characteristics of the ATFL, particularly its length and angulation, are strongly associated with CAI, the morphometric features of its bony attachment sites do not appear to contribute significantly. The ATFL/PTFL angle may be considered a reliable, indirect MRI marker in the assessment of CAI and should be considered in routine evaluations.