Effects of Barefoot and Shod on in Vivo Kinematics of the Tibiotalar and Subtalar Joint during Running Based on the High-speed Dual Fluoroscopic Imaging System

Objective: To independently quantify the in vivo degree of freedom(DOF) motion of the tibiotalar and subtalar joint under the conditions of barefoot and wearing shoes during running by using high-speed dual fluoroscopic imaging system(DFIS).Methods: Twelve healthy male runners were recruited in this study, the ankle joint model and the local coordinate system of the tibiotalar and subtalar joint was established by scaning the ankle in a neutral position. The fluoroscopic images of the foot were obtained under the condition of barefoot and wearing shoes with a heel strike pattern at a speed of 3±5% m/s, and the 6DOF motion characteristics of the tibiotalar and subtalar joint were calculated by 3D-2D registration. Paired sample t-test was used to analyze the6DOF data of the tibiotalar and subtalar joint under these two conditions. Results: Compared with barefoot, wearing shoes decreased the peak plantar/dorsiflexion angle during mid-stance and flexion and extension range of the tibiotalar joint throughout the stance period(P<0.05), and increased the peak dorsiflexion and eversion angle of the subtalar joint during mid-stance(P<0.05).However, no difference was found in the kinematics characteristics of the three translational directions(lateral/medial, anterior/posterior, distal/proximal) during the whole stance period. Conclusion: The findings of this study effectively overcome the weakness of traditional measurement methods could only obtain the motion of the single ankle joint. As wearing shoes increased the eversion of the subtalar joint, future studies are needed to explore the association between the eversion of the subtalar joint and runningrelated injuries. Meanwhile, the application of DFIS in quantifying the single joint motion is important because wearing shoes has different effects on the tibiotalar and subtalar joint during running.