Characteristics of Ankle Kinematics in patients with Ankle Instability with or without Osteochondral Lesion of the Talus

Longzhou Hua¹Chenglin Wu²Ling Zhang¹Longxiang Li¹Zhongmin Shi^2*Shaobai Wang^1*

• ¹Key Laboratory of Exercise and Health Science of Ministry of Education, Shanghai University of Sport, Shanghai, China
• ²Department of Orthopedics,, Shanghai 6th Peoples Hospital Affiliated to Shanghai Jiao Tong University, Shanghai, China

Purpose This study aimed to investigate ankle kinematic alterations in patients with chronic ankle instability (CAI), with or without concomitant osteochondral lesions of the talus (OLT), during level walking. Unlike previous studies that did not distinguish between isolated CAI and CAI with OLT, it used MRI-confirmed OLT diagnosis combined with 6-DOF motion analysis to identify OLT-specific kinematic patterns, The findings which may provide potential novel biomechanical markers to facilitate clinical screening and early diagnosis. Methods A total of 33 patients with CAI (15 with OLT and 18 without OLT) and 18 healthy controls were enrolled. Ankle kinematics were assessed using a joint motion analysis system during treadmill gait at a self-selected speed. Statistical Parametric Mapping (SPM) was applied to compare kinematic patterns across groups. Results Compared to healthy subjects, patients with OLT demonstrated reduced plantarflexion during early stance(1%–5%, 9%–10%), initial (67%–83%), and terminal swing (91%–100%) phases of the gait cycle, and reduced distal translation during initial swing(65%–69%) phases of the gait cycle in isolated CAI patients. Patients with OLT exhibited decreased ranges of motion (ROM) in plantarflexion (9.6°, P<0.001), internal rotation (3.0°, P=0.01) and lateral translation (0.3mm°, P=0.02), whereas patients with isolated CAI showed reduced inversion rotation (3.1°, P=0.009) and lateral translation (0.4mm°, P<0.001) compared with healthy controls. Conclusion The presence of osteochondral lesions further exacerbates kinematic abnormalities in ankles with CAI during gait. These findings enhance the understanding of the pathological mechanisms underlying CAI with OLT and offer potential biomechanical indicators for clinical assessment and rehabilitation planning. These distinct kinematic signatures—particularly reduced plantarflexion ROM in OLT patients versus reduced inversion ROM in isolated CAI—may serve as objective clinical markers to distinguish between these conditions, potentially reducing misdiagnosis rates and enabling clinicians to implement targeted rehabilitation strategies to prevent progression to ankle osteoarthritis. Trial registration Trial registration number: 102772025RT084.