Evaluation of gait symmetry in poliomyelitis subjects: Comparison of a conventional knee-ankle-foot orthosis and a new powered knee-ankle-foot orthosis

Background: Compared to able-bodied subjects, subjects with post-polio syndrome and poliomyelitis demonstrate a preference for weight-bearing on the non-paretic limb, causing gait asymmetry. Objectives: The purpose of this study was to evaluate the gait symmetry of the poliomyelitis subjects when ambulating with either a drop-locked knee-ankle-foot orthosis or a newly developed powered knee-ankle-foot orthosis. Study design: Quasi experimental study. Methods: Seven subjects with poliomyelitis who routinely wore conventional knee-ankle-foot orthoses participated in this study and received training to enable them to ambulate with the powered knee-ankle-foot orthosis on level ground, prior to gait analysis. Results: There were no significant differences in the gait symmetry index of step length (p=0.085), stance time (p=0.082), double-limb support time (p=0.929), or speed of walking (p=0.325) between the two test conditions. However, using the new powered knee-ankle-foot orthosis improved the symmetry index in step width (p=0.037), swing time (p=0.014), stance phase percentage (p=0.008), and knee flexion during swing phase (p0.001) compared to wearing the drop-locked knee-ankle-foot orthosis. Conclusion: The use of a powered knee-ankle-foot orthosis for ambulation by poliomyelitis subjects affects gait symmetry in the base of support, swing time, stance phase percentage, and knee flexion during swing phase. Clinical relevance A new powered knee-ankle-foot orthosis can improve gait symmetry for poliomyelitis subjects by influencing step width, swing time, stance time percentage, and knee flexion during swing phase when compared to ambulating with a drop-locked knee-ankle-foot orthosis.