Gait modification using an insole with protrusions enhancing plantar sensory feedback reduces maximum external knee...

Medial knee osteoarthritis (OA) progression is linked to increased mechanical stress in the medial knee compartment. The knee adduction moment (KAM) is a key indicator of this stress. The KAM can be reduced by adjusting the center of pressure (COP) trajectory during gait. Short-term training using plastic hemispherical protrusion stickers to enhance plantar sensory feedback enables voluntary control of the COP trajectory of healthy individuals. However, the effectiveness of this intervention for patients with knee OA is unclear.

This study aimed to verify whether gait modification training using an insole with enhanced plantar sensory feedback through protrusions can decrease the KAM and knee adduction angle during gait of patients with knee OA.

Twenty-two patients with knee OA underwent a three-dimensional (3D) gait analysis under control and insole conditions. Under the control condition, measurements were performed without any protrusions. Under the insole condition, hemispherical protrusions were attached to the heel and first metatarsal head. Participants received training to control their COP trajectory by loading onto the protrusions. Then, measurements were performed without protrusions.

The insole condition significantly reduced the maximum KAM (p < 0.001), knee adduction angle at the maximum KAM (p = 0.002), and knee adduction angular impulse (KAAI) (p = 0.013) compared with those under the control condition. No statistically significant differences were observed in step length and ground reaction force magnitude at the maximum KAM.

This intervention can effectively reduce the KAM and knee adduction angle of patients with knee OA.