The development of a flexion range-of-motion-adjustable knee joint for knee-ankle-foot orthoses and evaluation of gait in healthy individuals wearing it

[Purpose] To develop a knee joint for knee-ankle-foot orthoses that is easy to operate and allows for four levels of knee-flexion-movement adjustment, and to determine the effects of different flexion ranges of motion on knee flexion angle during gait. [Participants and Methods] Participants were eight healthy adults. Knee joint for knee-ankle-foot orthoses were made for each participant, and the knee flexion angle during gait was measured for each of the four knee joint settings: fixed in extension, 15° flexion range, 30° flexion range, and free flexion. [Results] Gait analysis showed that the knee flexion angle in the loading response phase was significantly greater in the 15° flexion range, 30° flexion range, and free-flexion settings than in the fixed-in-extension setting. While in the swing phase, the angle was greatest in the fixed setting, followed by the 15° flexion, 30° flexion, and free settings. [Conclusion] The proposed knee joint, when used in post-stroke gait practice using knee-ankle-foot orthoses, allows the gradual increase in the flexion range of motion of the joint as the weight-bearing capability of the lower limb improves, which would enable task-oriented practice similar to walking with ankle-foot orthoses as the next-stage target movement.