Changes in angular kinematics of the paretic lower limb at different orthotic angles of plantar flexion limitation of an ankle-foot-orthosis for stroke patients

[Purpose] An ankle-foot-orthosis (AFO) is an assistive brace that allows stroke patients to achieve an independent gait. Therefore, we examined whether or not the orthotic angle for plantar flexion limitation affects the kinematic parameters of the hip and knee joints on the affected side of patients with stroke. [Subjects and Methods] Fifteen patients with chronic hemiplegia were recruited for this study. Kinematic three-dimensional data was acquired, while patients walked along a walkway wearing AFOs under five different conditions of 0°, 5°, 10°, 15°, and 20° of plantar stop limitation angle in the orthotic joint. Peak angles of the hip and knee joints on the affected side were analyzed. [Results] At the peak angle of the knee joint, statistically significant differences were found only at mid-stance in the sagittal plane and the horizontal plane. However, no significant differences were observed among any of the orthotic limitation angles in the frontal plane. [Conclusion] According to the results, an orthotic limitation angle of more than 10° elicits changes in the knee joint angle at mid-stance in the sagittal and horizontal planes. This study provided basic data on postural changes of patients with stroke.