Anatomical factors in the development of medial-sided osteochondral lesion of the talus: a comparative analysis.

Purpose: The aim of this study was to determine anatomical predictors for the occurrence of medial osteochondral lesions of the talus (OLT), by analyzing morphometric variables obtained from magnetic resonance imaging (MRI).

Methods: A total of 430 ankles with 215 ankle MRIs from patients with nontraumatic OLTs on the medial side of the talar dome and an equal number of age, sex, and side-matched healthy controls were analyzed in this retrospective study. The specific MRI parameters that were measured include the anterior opening angle of the talus (AOT), the angle between the tibial axis and medial malleolus (TMM), the angle of the tibial plafond to the malleoli (PMA), the angle between the anterior and posterior talofibular ligaments (ATFL-PTFL angle), length of the trochlea tali arc (TAL), sagittal length of distal tibial articular surface (TAS), the ratio of the sagittal length of distal tibial articular surface to the length of the trochlea tali arc (TAS/TAL), and the depth of the incisura fibularis (IncDep).

Results: AOT, IncDep, ATFL-PTFL angle, PMA, TMM, TAL, and TAS/TAL exhibited significant differences between the two groups. The established cut-off values were 13° (AUC 0.875) for AOT, 3.7 mm (AUC 0.565) for IncDep, 78° (AUC 0.729) for ATFL-PTFL angle, 14° (AUC 0.581) for PMA, 15° (AUC 0.907) for TMM, 34.3 mm (AUC 0.599) for TAL, and 0.81 (AUC 0.719) for TAS/TAL. Multivariate logistic regression analysis revealed Odds Ratio (OR) = 22.22 for AOT > 13°, OR = 4.23 for ATFL-PTFL angle > 78°, OR = 1.99 for PMA ≤ 14°, OR = 31.598 for TMM > 15°, OR = 3.79 for TAS/TAL ≤ 0.81.

Conclusion: This study highlights the significance of anatomical parameters, particularly the TMM and AOT, as key predictors of OLT.