Time Series Knee Joint Angle Analysis During Gait for Patients with Down Syndrome by 3d Pose Estimation

Down syndrome is the most common chromosomal abnormality. In recent years, the frequency of births with Down syndrome has been increasing in Japan. One of the reasons for this is the trend toward late childbearing. Many children with Down syndrome often have gait problems such as Genu valgum and Genu varum. In order to solve such gait problems, custom- made insoles need to be created. This is because the shape of the feet and the way of walking vary from patient to patient. In addition, it is necessary to investigate whether these custom-made insoles are suitable for the patients with Down syndrome or not. Currently, the evaluation is done visually by doctors and physical therapists, however the criteria for judgment are unclear. Therefore, we worked to develop a system to determine whether custom-made insoles would improve Genu valgum and Genu varum. Since the children with Down syndrome rarely walk straight when taking gait videos, we focused on performing gait analysis in 3D instead of 2D, which has been performed previously. In this study, we estimated the joint position coordinates of a person from a walking video using 3D pose estimation in order to quantitatively evaluate the gait condition of children with Down syndrome. Additionally, by detecting the time of knee joint loading and measuring the knee joint angle, we were able to propose a system that can confirm symptoms such as genu valgum and genu varum. This system is expected to be easier than the existing 3D analyzers for gait analysis of patients with Down syndrome. As a future work, the accuracy of the system itself needs to be evaluated using an existing 3D motion analyzer that measures with markers.