Background
It is known that a lateral wedge insole (LWI) decreases medial loading stress in the knee. Medial meniscus pathology, such as a degenerative tear or a root tear, leading to malfunction and medial meniscus extrusion (MME), is a critical condition that leads to severe osteoarthritis (OA). However, the effect of LWI on MME is still unknown. The objective of this study was to investigate the effect of LWI use on MME in knee OA using ultrasonography.