Abstract
Plastic ankle-foot orthoses (PAFOs) are often used as assistive devices for patients with hemiplegia. In this study, force exerted on PAFOs during walking was measured using a sensor installed at the top of the calf region on the PAFO, where the structure of the PAFO exerts minimal influence on measurements, and the data were analyzed. First, PAFOs with incorporated sensors were individually prepared for 3 healthy individuals and for 3 patients with hemiplegia. Mechanical data were then obtained while individuals wore the PAFOs during level-ground walking. We found that at the early stance phase, force vectors apply at a slightly lower region of the prosthetic rear wall, the level of which is the same as the upper belt, and at the late stance phase, they usually apply at the upper belt region. We also found that the waveform of posterior force applied by the PAFOs coincide with that of the bending angle of the PAFOs. From these findings, we found that the approximate posterior direction force applied by the PAFOs, which usually must be measured using costly sensors and modified PAFOs, can be easily estimated by measuring and calculating from PAFO bending angle.
