Can Slight Variations to Lateral Wedge Insoles Induce Significant Biomechanical Changes in Patients with Knee Osteoarthritis?

Abstract

Lateral wedge insoles are recommended in order to minimize the impacts of osteoarthritis of the knee. The amount of wedging required to induce a biomechanical response with clinical significance is still controversial. This study aimed to investigate the immediate biomechanical effects of different amounts of wedging in symptomatic medial knee OA. A 3D motion capture system and five force platforms were used to acquire walking kinematic and kinetic data along a 10 m walkway. Each participant was tested for six different lateral wedge insoles (0, 2, 4, 6, 8, and 10°) in a randomized order. Thirty-eight patients with medial osteoarthritis of the knee were recruited. The application of insoles resulted in an incremental reduction of the first peak of the external knee adduction moment under all experimental conditions in comparison with the control condition (0° insole). A significant increase (p < 0.05) was observed in peak ankle eversion and in ankle eversion at the first peak of the external knee adduction moment with insoles higher than 8° and 6°, respectively. Slight variations to lateral wedge insoles, greater than 2°, appear to induce significant biomechanical changes in patients with knee osteoarthritis.