Knee and ankle biomechanics with lateral wedges with and without a custom arch support in those with medial knee osteoarthritis and flat feet

ABSTRACT This study compared immediate changes in knee and ankle/subtalar biomechanics with lateral wedge orthotics with and without custom arch support in people with knee osteoarthritis and flat feet. Twenty‐six participants with radiographic evidence of medial knee osteoarthritis (22 females; age 64.0 years [SD 8.0 years], BMI 27.2 kg/m2 [4.2]) and flat feet (median foot posture index = + 5) underwent three‐dimensional gait analysis for three conditions: Control (no orthotic), lateral wedge, and lateral wedge plus arch support. Condition order was randomized. Outcomes included frontal plane knee and ankle/subtalar biomechanics, and comfort. Compared to the control, lateral wedge and lateral wedge with arch support reduced the knee adduction moment impulse by 8% and 6%, respectively (p