Kinematic effects of lateral wedged insoles in patients with medial knee osteoarthritis

[Purpose] To examine the effect of lateral wedged insoles on the rotation mechanism of the knee joint in patients with knee osteoarthritis. [Participants and Methods] The participants included 11 patients with medial knee osteoarthritis. We asked all participants to stand up from a 40-cm-high chair, and we measured the rotation angle of the knee joint during the movement. The standing motion was performed under four conditions: barefoot and with 7-, 10-, and 13-mm lateral wedged insoles. We also measured four healthy participants as controls for comparison. [Results] During the standing motion, we internally rotated the tibia relative to the femur. In healthy participants, we measured 19.6° internal rotation of the tibia relative to the femur. Patients with knee osteoarthritis had internal rotations of approximately 9.8° when barefoot and 7.1°, 6.4°, and 7.1° when wearing lateral wedged insoles of 7, 10, and 13 mm, respectively. [Conclusion] Lateral wedged insoles do not modify the knee joint rotation motion of patients with knee OA to the correct style.