Case Study: Improving Knee Extension with Floor-Reaction Ankle-Foot Orthoses in a Patient with Myelomeningocele and 20?? Knee Flexion Contractures

Abstract

Floor-reaction ankle-foot orthoses (FRAFOs) were fit to a patient with an L-5 le el myelomeningocele to show their effect on increasing knee extension and the knee extension moment in the presence of 20° bilateral knee flexion contractures. It was hypothesized that FRAFOs would pre ent the crouchedtype gait pattern commonly seen in those with myelomeningoceles. Because of the rigid nature of the FRAFO, it was thought this would increase the external knee-extension moment and extend the knees to their maximum range. A patient with myelomeningocele underwent gait analysis testing while barefoot and while wearing FRAFOs set in 10° dorsiflexion. Joint kinetic and kinematic, along with electromyographic data on the astus lateralis and rectus femoris were determined. Results showed a peak plantarflexor moment in late stance of 0.70 N-m/kg body weight while the patient was barefoot and 1.32 N»m/kg body weight while the patient was wearing the FRAFO (P <.0001). Knee extension during the barefoot trails was 20.5°, and was 12.3° during the FRAFO trials (P <.0001). Electromyographic acti ity of the rectus femoris in terminal stance decreased significantly during FRAFO trials compared to the barefoot trials (307 mV ersus 53 mV; P <.0001) consistent with the impro ed knee extension. FRAFOs set in 10° dorsiflexion pro ided a significant increase in knee extension and knee-extension moment during gait for this patient with myelomeningocele, despite 20° bilateral knee-flexion contractures