Ankle Joint and Rearfoot Biomechanics During Toe‐In and Toe‐Out Walking in People With Medial Compartment Knee Osteoarthritis

Background Toe‐in and toe‐out walking are 2 strategies that have been shown to be effective in reducing the knee adduction moment in people with knee osteoarthritis. However, despite a positive biomechanical impact on the knee, altering foot rotation may impart unintended forces or joint positions on the ankle that could impact joint health. The kinematic and kinetic changes at the ankle during toe‐in or toe‐out walking have yet to be examined. Objective To examine ankle/rearfoot biomechanics during toe‐in and toe‐out walking in those with knee osteoarthritis. Design Single‐session repeated measures design to compare ankle biomechanics during walking with 4 different foot rotations. Setting University motion analysis laboratory. Participants A convenience sample (N = 15) of males and females with a diagnosis of medial knee osteoarthritis confirmed by radiographs. Methods Participants walked in 4 conditions guided by real‐time biofeedback: (1) toe‐in (+10°), (2) zero rotation (0°), (3) toe‐out (−10°), and (4) toe‐out (−20°). Ankle and rearfoot kinematics and kinetics were examined during barefoot over‐ground walking. Main Outcome Measures Ankle joint angles, moments, moment impulses, and foot rotation. Results Overall, toe‐in compared to toe‐out walking decreased (P = .03) peak rearfoot eversion (toe‐in = −1.6°; 10° toe‐out = −3.7°; 20° toe‐out = −4.1°). Toe‐in compared to toe‐out walking also increased rearfoot inversion at initial contact (7.4° vs 3.1° at 10° toe‐out and 1.9° at 20° toe‐out; P