To study the characteristics of gait behavior in a mouse model of chronic ankle instability and provide a reference for the study of the mechanism of chronic ankle instability as well as drug screening and evaluation.

Thirty C57BL/6J male mice were randomly divided into a control group (n=15) and an injury group (n=15). In the control group, the ankle joint underwent sham operation, and in the injury group, the anterior talofibular ligament and calcaneofibular ligament of the left ankle joint were transected. Gait parameters were analyzed in each group using TreadScan passive gait analysis system.

Compared with the control group, the injury group showed a 28.43% increase (P<0.05) in average standing time and a 23.07% increase (P<0.05) in the percentage of standing time, whereas the average swing time and the percentage of swing time were shortened by 50.63% (P<0.001) and 19.75% (P<0.01), respectively. The average braking time and average stride time in the injury group were also shortened by 18.37% (P<0.01) and 37.86% (P<0.001), respectively. The injury group exhibited a decrease in step length, anterior-posterior step width, and mediolateral step width by 36.96%, 13.66%, and 8.10%, respectively. The total movement speed and instantaneous speed decreased by 8.05% and 11.12%, respectively, while the stride frequency increased by 51.41%. The average footprint area and average maximum standing area decreased by 8.8% and 13.24%, respectively, and foot pressure decreased by only 3%. The plantar pressure distribution in the injury group was uneven, with a more obvious decrease in plantar pressure in the hindfoot, especially a 13.92% decrease in plantar pressure in the right posterior quadrant.

Mice with chronic ankle instability adopt a more conservative walking pattern during the motion, reducing movement volume and amplitude to improve coordination and stability during walking.