The indication for medical knee-ankle-foot orthosis based on the results of analysis of ground reaction force : Investigation of ankle joint adjustment before changing from KAFOs to AFOs

Abstract

In stroke patients, changing from a knee-ankle-foot orthosis (KAFO) to an ankle-foot orthosis (AFO) is an important element of gait acquisition. During this process, gait training wearing a KAFO with a free motion knee joint is widely experienced, but foot adjustment is largely dependent on empirical rules. According to reports on AFOs, while there is no disagreement on the effectiveness of plantar flexion resistance, opinion is divided over dorsiflexion resistance that presumably supplements knee extension, such as suppression of the propulsive force. In the present study, we examined the ground reaction force during walking with or without applying plantar dorsiflexion resistance in 12 healthy subjects wearing a KAFO with a free motion knee joint. We found that even when plantar dorsiflexion resistance was applied, the propulsive force was maintained, and the knee joint tended to be stabilized in the direction of extension. These results suggest the possibility that plantar dorsiflexion resistance in KAFO may be an effective adaptation toward changing to an AFO.