In patients post stroke or post onset of MS who demonstrate ankle dorsiflexion with preserved tibilais anterior function the principal gait deficit may be loss of ankle eversion due to peroneus longus & brevis paresis. The presenting gait feature is loss of a normal plantagrade foot position during & at the end of swing phase of gait with decreased ankle stability in initial stance phase of gait.

Loss of ankle eversion poses a risk for falls and increases the physiologic cost of walking. Gait endurance and distance walked may also be affected.

Correction of ankle eversion is achieved through electrode placement over the common peroneal nerve in the lateral popliteal fosa & over the superficial branch of the common peroneal nerve at the fibular head to balance eversion with dorsiflexion.

Patients with a gait deficit due to loss of ankle eversion should not be overlooked for a dropped foot stimulator as stimulation can restore a more normal gait pattern, make walking safer/less tiring and increase walking range and confidence.