Hip Sway in Patients With Hip Osteoarthritis During One-Leg Standing With a Focus on Time Series Data

This study aimed to investigate the hip sway and the relationship between the center of pressure (CoP) and kinematic parameters regarding the time series scaling component α in patients with hip osteoarthritis (OA) during a one-leg standing task. The scaling exponent α, SD, hip sway maximal acceleration change, and balance performance, which was measured using CoP parameters, were compared between hip OA and control groups during a one-leg standing task. The relationships between balance performance with CoP parameters and kinematic parameters were investigated with the regression analysis. In the hip OA group, the scaling exponent α was smaller in the medial-lateral direction, and the SD and maximal amount of change in hip sway acceleration were larger in the anterior-posterior direction in the hip OA group. In this group, the CoP parameters were significantly associated with α in the medial-lateral direction (negatively) and in the anterior-posterior direction (positively). In the hip OA group, hip sway adaptability in the medial-lateral direction was limited, while the anterior-posterior direction showed greater movement.