Effect of ankle-foot orthosis on active ankle moment in patients with hemiparesis.

The paper investigates the effect of dorsi/plantar rigidity and the initial angle of ankle-foot orthoses (AFOs) on the moment generated by ankle musculature (referred to as active ankle moment) during gait in patients with hemiparesis. In the early stance phase, the active ankle moment in the direction of dorsiflexion is negligible, and AFOs play an important role in supplementing weak dorsiflexion. In mid to late stance, the moment generated by AFOs is very small compared with the active ankle moment in the direction of plantarflexion. AFOs therefore play only a limited role in assisting plantar flexors during this period. The active ankle moment in the direction of plantarflexion varies significantly with changes in the rigidity and initial angle of AFOs in 11 out of 20 subjects. The implication of this finding is discussed in relation to the need for dynamic matching of AFOs in individual patients with hemiparesis.