The Difference in Kinematic Parameters During Gait Between the Patients with Knee Osteoarthritis and Healthy Controls Using an Insole with a Single Inertial Measurement Unit: A Case-Control study

Abstract Background: Gait disturbance is a critical problem in patients with osteoarthritis of the knee (KOA). The inertial measurement unit (IMU) is small size and lightweight allows for the measurement of patients without physical constraints. The purpose of this study was to investigate whether an insole with a single IMU can detect differences in kinematic parameters during gait between patients with KOA and healthy controls.Methods: Twenty patients with KOA, for whom unilateral total knee arthroplasty was planned, and 13 age-matched control subjects were included in this study. Participants wore shoes with IMU-equipped insoles and were required to walk across an 8-m walkway at a self-selected speed and foot movement data were collected during gait. We compared the spatiotemporal and kinematic parameters on the right side in healthy controls and both sides in patients with KOA.Results: The self-selected walking speed and stride length in the KOA group were significantly lower than those of the controls. The foot extension angular velocity at the toe-off (TO) was significantly smaller on the affected side than on the contralateral side (p<0.001) and in the healthy controls (p<0.001). During the swing phase, foot forward acceleration was significantly smaller on the affected side of KOA compared with healthy controls (p=0.005). Furthermore, foot upward acceleration at the initial contact (IC) in patients with KOA was significantly lower on the contralateral side compared with that of healthy controls (p=0.0167) but not on the affected side (p=0.344), despite a decrease in walking speed. Conclusions:The insole with a single IMU can detect differences in foot kinematics during gait between patients with KOA and healthy controls. Our findings indicate that patients with KOA exhibit a dysfunction of the push-off at TO and shock absorption at the IC on the affected side.