Objective:To investigate the biomechanical correlation between ankle instability and osteochondral lesions of the talus (OLT) under loading conditionsMethods:A healthy 29-year-old male volunteer was selected for the study. A 64-slice spiral CT scan of the right lower limb was performed to construct a detailed finite element model of the ankle joint, including ligaments and cartilage. Three injury models were created: models of distal tibiofibular syndesmosis injury, lateral collateral ligament injury, and a combined injury of the distal tibiofibular syndesmosis and lateral collateral ligament. Differences in stress distribution on the tibiotalar joint surface, talus stress, and talus displacement were analyzed through anterior drawer test, inversion stress test, and external rotation stress test.Results:In the anterior drawer test, as the forward traction force increased (40, 60, 80, 100, 120, 140, and 150 N), all the injury models showed a progressive increase in tibiotalar joint surface stress, talus stress, and talus displacement. The combined injury model showed the highest tibiotalar joint surface stress (32.6 MPa), while the lateral collateral ligament injury model demonstrated the highest talus stress (56.5 MPa). Talus displacement increased significantly with traction, reaching the maximum (4.88 mm) in the combined injury model under 150 N. In the inversion stress test, stress on the tibiotalar joint surface in the lateral collateral ligament injury model was concentrated on the posterior-lateral and posterior-medial regions, whereas in the combined injury model, stress on the tibiotalar joint surface was predominantly concentrated in the posterior-medial region. Talus stress was localized to the talus neck and body in all the models, with the combined injury model showing the largest talus displacement (8.46 mm). In the external rotation stress test, stress on the tibiotalar joint surface was mainly distributed in the posterior-medial, posterior-lateral, and anterior-lateral regions in all the models. Talus stress was concentrated at the talus neck and body. The combined injury model exhibited the greatest talus displacement (12.50 mm).Conclusion:Ankle instability, particularly from combined injuries of the distal tibiofibular syndesmosis and lateral collateral ligament, significantly increases the stress concentration and talus displacement under loading conditions, thus elevating the risk of OLT.

Objective:To investigate the biomechanical correlation between ankle instability and osteochondral lesions of the talus (OLT) under loading conditionsMethods:A healthy 29-year-old male volunteer was selected for the study. A 64-slice spiral CT scan of the right lower limb was performed to construct a detailed finite element model of the ankle joint, including ligaments and cartilage. Three injury models were created: models of distal tibiofibular syndesmosis injury, lateral collateral ligament injury, and a combined injury of the distal tibiofibular syndesmosis and lateral collateral ligament. Differences in stress distribution on the tibiotalar joint surface, talus stress, and talus displacement were analyzed through anterior drawer test, inversion stress test, and external rotation stress test.Results:In the anterior drawer test, as the forward traction force increased (40, 60, 80, 100, 120, 140, and 150 N), all the injury models showed a progressive increase in tibiotalar joint surface stress, talus stress, and talus displacement. The combined injury model showed the highest tibiotalar joint surface stress (32.6 MPa), while the lateral collateral ligament injury model demonstrated the highest talus stress (56.5 MPa). Talus displacement increased significantly with traction, reaching the maximum (4.88 mm) in the combined injury model under 150 N. In the inversion stress test, stress on the tibiotalar joint surface in the lateral collateral ligament injury model was concentrated on the posterior-lateral and posterior-medial regions, whereas in the combined injury model, stress on the tibiotalar joint surface was predominantly concentrated in the posterior-medial region. Talus stress was localized to the talus neck and body in all the models, with the combined injury model showing the largest talus displacement (8.46 mm). In the external rotation stress test, stress on the tibiotalar joint surface was mainly distributed in the posterior-medial, posterior-lateral, and anterior-lateral regions in all the models. Talus stress was concentrated at the talus neck and body. The combined injury model exhibited the greatest talus displacement (12.50 mm).Conclusion:Ankle instability, particularly from combined injuries of the distal tibiofibular syndesmosis and lateral collateral ligament, significantly increases the stress concentration and talus displacement under loading conditions, thus elevating the risk of OLT.