The effects of ankle-foot orthoses on the ankle and knee in persons with myelomeningocele: an evaluation using three-dimensional gait analysis.

The purpose of this study was to determine the effects of the ankle-foot orthosis (AFO) on gait patterns in patients with low-level myelomeningocele and to identify any abnormal gait patterns that may lead to future knee instability and pain. A total of 28 children (26 L4-level sides, 18 L5-level sides, and 10 S1-2-level sides) underwent a three-dimensional gait analysis when ambulating barefoot and with AFOs. Results show significant improvements in sagittal plane function with reductions in excessive ankle dorsiflexion, increases in peak plantar flexor moment, and reductions in crouch and knee extensor moment in the L4 and L5 groups. The only improvement in the S1-2 group was a reduction in excessive dorsiflexion, but there was a reduction in power generation at the ankle. The S1-2 group had normal transverse plane knee motion in stance during barefoot walking that increased significantly (p < 0.01) with the AFO. Both the L5 and L4 groups showed greater-than-normal transverse plane knee motion in stance during barefoot walking that also increased significantly (p < 0.01) with the AFO. The results suggest that excessive knee transverse plane rotation may contribute to knee instability more than coronal plane abnormalities. The AFO in S1-2-level patients may be more detrimental for the knee than barefoot walking.