Coordination pattern of the thigh, pelvic, and lumbar movements during the gait of patients with hip osteoarthritis

Hip and relevant joint movement has been reported during gait in patients with hip osteoarthritis; however, there are limited reports on segment movement and their coordination pattern. It is important to investigate the relationship among relevant segment movements, focused on the time series data, in patients with osteoarthritis. This study aimed to quantify and assess the coordination pattern of lumbar, pelvic, and thigh movements during gait in patients with hip osteoarthritis and in a control group. An inertial measurement unit was used to measure the lumbar, pelvic, and thigh angular velocities during gait of 11 patients with hip osteoarthritis and 11 controls. The vector coding technique was applied, and the coupling angle and the appearance rate of coordination pattern of lumbar, pelvic, and thigh movements in each direction were calculated and compared with the control group. Compared with the control group, with respect to the lumbar/pelvic segment movements, the patients with hip osteoarthritis spent more rate in anti-phase and lesser rate in in-phase lateral tilt movement. With respect to the pelvic/thigh segment movements, the patients with hip osteoarthritis spent more rate within the proximal- and in-phases for lateral tilt movement. Further, patients with osteoarthritis spent lesser rate in the distal-phase for anterior/posterior tilt and rotational movement. Patients with hip osteoarthritis could not move their pelvic and thigh segments separately, which indicates the stiffness of the hip joint. However, our results suggested that their thoracic movement (especially in the lateral tilt movement) could compensate for their inability to move the pelvic and thigh segments separately. To maintain the gait ability, maintaining the spinal mobility is also considered important.