Differences In Joint Kinematics During Walking In Individuals With Bilateral And Unilateral Chronic Ankle Instability

Individuals with unilateral chronic ankle instability (CAI) show altered walking patterns compared to the healthy controls. Bilateral changes in joint kinematics following a unilateral joint injury suggest central alterations in sensorimotor function. However, the differences in joint kinematics between individuals with bilateral and unilateral CAI remain unclear. PURPOSE: To investigate the differences in joint kinematics during walking in individuals with bilateral and unilateral CAI. METHODS: Sixty participants were recruited: 20 individuals with bilateral CAI (bilateral), 20 with unilateral CAI (unilateral), and 20 healthy controls (control). CAI was determined by the International Ankle Consortium's position statement. We used 44 reflective markers and a force plate to calculate joint angles from initial contact to toe-off (0-100%) across five walking trials. Functional data analysis was used to assess between-group differences in joint kinematics. RESULTS: The bilateral exhibited up to 2.3° more dorsiflexion and 3° more hip flexion during 0-67% and 0-100% of the stance phase compared to the unilateral group. The bilateral exhibited up to 3.2° more dorsiflexion during 3-100% of the stance phase than the control. The bilateral exhibited up to 2.9° more inversion during 0-65% and 80-100% of the stance phase than the unilateral, and 1.8° more inversion during 93-100% of the stance phase than the control. The unilateral group showed up to 1.8° more eversion during 0-75% of the stance phase than the control. CONCLUSION: Individuals with bilateral CAI exhibited increased dorsiflexion and hip flexion, possibly as a protective mechanism against instability and to leverage the hip joint’s mechanical advantages. Increased inversion, which raises the risk of lateral ankle sprains was also evident in bilateral CAI. In contrast, individuals with unilateral CAI demonstrated less inversion, indicating a more stable ankle position. Thus, individuals with bilateral and unilateral CAI involve different movement strategies, with bilateral CAI posing a higher risk for lateral ankle sprains, which may highlight the central nervous system’s role in managing sensorimotor function.