Long-term use of minimal footwear in older adult women with knee osteoarthritis: Mechanisms of action in the knee adduction moment.
Studies have shown the short- and long-term effects of wearing minimalist footwear in reducing knee loads in patients with knee osteoarthritis (OA). This study aimed to investigate the mechanisms underpinning the reduction in external knee adduction moment (EKAM) in older adult women who wore this type of footwear through a randomized controlled trial. Fifty-six participants with medial compartment knee OA were equally allocated to either an intervention group (IG) that wore minimalist footwear (Moleca®) or to a control group (CG) that continued regular clinical treatment for OA for six months. The influence of lower limb joint kinematics and joint frontal moments, center of pressure displacement, and foot progression angle in predicting the reduction of EKAM were assessed after a six-month intervention. Surprisingly, none of the seven independent variables predicted the first peak EKAM in the multiple regression model for the IG. For the CG, the increase of one unit in the first peak of the hip adduction moment resulted in a 1.01 units increase in the first peak EKAM. Additionally, a one-unit reduction in the ankle eversion angle resulted in an increase of 0.16 units in the percent change in the first peak EKAM. Thus, wearing the Moleca® shoe for six months helped the participants keep a natural gait pattern without increasing the hip moment or the ankle inversion angle compared to the women who did not wear the Moleca® footwear. ClinicalTrials.gov (NCT01342458).