Magnetic resonance imaging-based morphologic features associated with ankle sprain and increased risk of ligament...

To identify magnetic resonance imaging (MRI)-based morphologic features of the distal tibiofibular syndesmosis and talocrural joint associated with ankle sprains and to determine which parameters are specifically linked to an increased risk of ligament tears after sprains.

This retrospective study included ankle MRI examinations performed between January 2022 and November 2025. Two analytic datasets were constructed: Dataset 1 compared patients with ankle sprains and MRI-confirmed ligament tears to healthy controls with completely normal ankle MRIs; Dataset 2 compared controls, patients with sprains but no ligament tears, and patients with sprains and ligament tears. Standardized morphometric measurements of the distal tibiofibular syndesmosis and talocrural joint were obtained, including absolute and ratio-based parameters. Group comparisons were performed using appropriate univariable tests with multiple-comparison correction. Multivariable logistic regression was used to identify independent predictors of ligament tears. Inter-reader reliability was assessed using intraclass correlation coefficients and Bland-Altman analysis.

In Dataset 1, compared with healthy controls, tibiofibular clear space and the fibular notch depth-to-tibial thickness ratio were significantly higher in patients with ankle sprains and ligament tears, whereas the lateral malleolar height-to-talar articular width ratio was significantly lower (all P < 0.05). Multivariable analysis demonstrated that tibiofibular clear space and the fibular notch depth-to-tibial thickness ratio were independent predictors. In Dataset 2, tibiofibular clear space, fibular notch depth-to-tibial thickness ratio, and lateral malleolar height-to-talar articular width ratio differed significantly across three groups (all P < 0.05). Notably, only the lateral malleolar height-to-talar articular width ratio independently differentiated patients with sprains and ligament tears from those without tears (P = 0.025). Model discrimination was moderate to good (area under the curve: 0.699 and 0.785).

Specific MRI-based morphologic features are associated with both ankle sprain susceptibility and an increased risk of ligament tears. Among these, the lateral malleolar height-to-talar articular width ratio appears to be a morphometric parameter associated with an increased likelihood of ligament tears.

MRI-based morphometric assessment, particularly the lateral malleolar height-to-talar articular width ratio, may help identify patients with ankle sprains who are at an increased risk for ligament tears and support more individualized clinical management.