The Effect of the Lateral Wedge Insoles on Cumulative Loads and Changes in Physical Activity of Patients With Knee Osteoarthritis

Knee pain in patients with knee osteoarthritis leads to decreased physical activity. The knee adduction moment impulse is closely related to pain, multiplied by the number of steps per day, reflecting the cumulative knee adductor load (CKAL). The intervention of lateral wedge insole (LWI) can relieve pain by reducing the CKAL, but changes in physical activity have not been investigated. This study aimed to determine the effect of the LWI on the CKAL and changes in physical activity. Twenty-one patients with knee osteoarthritis were enrolled in our study. The knee adduction moment impulse was estimated by a VICON system without LWI (baseline) and with LWI immediately (T0) at the initial visit and 3 months after intervention (T1). An accelerometer was worn for 8 days to monitor daily steps and activity. The physical activity was performed at baseline and T1. Pain was evaluated at baseline, T0, and T1. Pain and CKAL were reduced significantly after the intervention of the LWI. The knee adduction moment impulse at T0 and T1 was reduced compared with the baseline. There was no significant change in daily steps. However, physical activity significantly decreased in terms of the total duration of activity, standing, and periods of standing and walking.