Stroke, brain injury, incomplete spinal cord injuries, and peripheral neuropathies frequently result in dysfunction of the foot dorsiflexors and evertors. A controlled examination of aspects of these disabilities was conducted with normal volunteers who underwent a temporary peroneal nerve block. The effects of peroneal nerve paralysis were analyzed to quantitatively describe the resulting gait abnormalities and to assess the effectiveness of orthoses in restoring a normal gait pattern. Kinematic and kinetic measurements were made during normal ambulation, ambulation with a right peroneal nerve paralysis, and ambulation with a paralysis and an ankle-foot orthosis (AFO) with three different adjustments: a posterior stop set in 5° plantarflexion, a posterior stop set in 5° dorsiflexion, and spring-assisted dorsiflexion. The peroneal paralysis produced abnormalities during both the stance and swing phases of gait. During early stance there was a decrease in the length of the heelstrike phase and a reduction in the peak plantarflexion movement (p < 0.01). During midstance there was an increase in the range of inversion-eversion achieved suggesting medial-lateral instability (p < 0.01). The second vertical force peak and the aft-shear force peak were reduced (p < 0.05) as were the peak dorsiflexion movement and the opposite steplength (p < 0.01). These reductions are believed to be due to medial-lateral instability during pushoff. Subjects demonstrated a steppage gait during swing phase and increased inversion just prior to heelstrike (p < 0.05). All three of the AFO adjustments were effective in restoring the length of the heelstrike phase, the ground reactive force amplitudes, the peak dorsiflexion movement, the opposite steplength and medial-lateral stability of the ankle. The AFO with the posterior stop in 5° dorsiflexion produced an increase in the peak knee flexion movement (p < 0.01) and a decrease in the length of pushoff phase (p < 0.05); it also positioned the ankle in excessive dorsiflexion at heelstrike as compared to normal (p < 0.01). The AFO with spring-assisted dorsiflexion was not effective in restoring the peak plantarflexion movement to normal values (p < 0.01). During ambulation with the AFO with the posterior stop in 5° plantarflexion, the duration of the pushoff phase was decreased as compared to normal (p < 0.05) and the steppage gait persisted as evidenced by a greater than normal maximum foot clearance (p < 0.05) and less than normal ambulation speed (p = 0.05). The results suggested that for peroneal paralysis the optimal position for a posterior stop is one which maintains the minimum ankle angle required for foot clearance so as to reduce the potential for an increased knee flexion moment and excessive dorsiflexion during the heelstrike and pushoff phases of gait. The AFO with spring-assisted dorsiflexion was effective in providing safe foot clearance, but was not sufficiently stiff to stimulate the lengthening contraction of the foot dorsiflexors during heelstrike.
|Number of pages
|Archives of physical medicine and rehabilitation
|Published - Jan 1 1986
ASJC Scopus subject areas
- Physical Therapy, Sports Therapy and Rehabilitation