Effectiveness of insoles in treating medial osteoarthritis of the knee

In the linked randomised controlled trial (doi:10.1136/bmj.d2912) Bennell and colleagues assessed the effect of lateral wedge insoles on the symptoms and progression of medial knee osteoarthritis.1 They found that such insoles worn for one year provide no symptomatic or structural benefit compared with a flat control insole.

The medial tibiofemoral compartment is most commonly affected in osteoarthritis of the knee, probably because an external adduction moment (the tendency of a force to twist or rotate an object) in the knee during walking causes compression of the medial compartment.2 Varus knee alignment (bowleg) has been reported as one of the best predictors of a high knee adduction moment during walking, and there is strong evidence that varus alignment or a high adduction moment predicts faster progression of knee osteoarthritis.3 Lateral wedged insoles and valgus knee braces have therefore been developed as a conservative approach to altering mechanical loading and reducing the symptoms and progression of knee osteoarthritis. Several studies show that lateral …