Effects of lateral wedge insole application on medial compartment knee osteoarthritis severity evaluated by ultrasound

Abstract 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. Methods Thirty-one knees from 18 patients with knee OA diagnosed radiographically were allocated to the OA group (mean age, 73.6 years; sex M:F, 2:16). Twenty-two knees from 11 volunteers without knee OA were also enrolled as an age-matched control group. MME was evaluated using ultrasonography with the patients in three positions: supine, standing without LWI, and standing with LWI. Results In both groups, the mean values of the MME increased significantly when patients were in the standing position compared to the supine position. In the OA group, MME significantly decreased with LWI use. There was no significant difference in MME between use and non-use of an LWI in the control group. Conclusions The LWI could significantly decrease MME in patients with knee OA.