[A comparison of ankle fixation between two kinds of low-temperature plastic anterior ankle foot orthoses]

The low-temperature ankle foot orthosis (AFO) was designed in the anterior leaf type, called anterior AFO, to meet the need of indoor barefoot walking. It could be easily molded and remolded to fit the foot, as well as to adjust the position of the foot and ankle. Two kinds of low-temperature plastic anterior ankle foot orthoses, anterior encased and anterior direct molding ankle foot orthoses, were compared to analyze the effectiveness of ankle fixation in plantar flexion and inversion. Force was applied to each of the anterior AFOs at the anterior-middle and anterior-lateral sides to simulate the movement of ankle plantar flexion and inversion. At the same time, the deformation in plantar flexion and inversion of both anterior AFOs were recorded to analyze the relationship between force and the deformed angle. The results showed that plantar flexion deformed angles of the anterior direct molding AFO were 2.6 times more flexible than anterior encased AFO. The ankle inversion deformed angles of the anterior direct molding AFO were 3 times more flexible than the anterior encased AFO in inversion. These results support our belief that anterior encased AFO is more effective in controlling ankle plantar flexion and inversion than anterior direct molding AFO, especially for severe spastic hemiplegia in gait correction.