Article

Abnormal within and across-joint synergistic behaviors have been reported in the
lower limb post stroke. It is unknown, however, whether these impairments limit
adaptive movement strategies in response to imposed kinematic constraints. In
this context, the goal of this pilot study was to examine changes to
three-dimensional swing phase kinematics of the paretic hip, knee, and ankle
joints and pelvis induced by AFO use in subjects with chronic stroke. Overground
gait analysis was performed on 9 ambulating hemiplegic subjects with and without
their AFOs. Both the toeoff and peak ankle dorsiflexion angles were significantly
decreased in the no AFO condition. Likewise, the peak and toeoff swing phase
pelvic obliquity angles significantly increased when the AFO was removed (6.47
degrees (2.0 SD) vs. 8.16 degrees (2.8 SD), paired t-tests, p=0.03 and 0.8
degrees (3.1 SD) vs. 2.9 degrees (1.1 SD), paired t-test, p=0.02, respectively).
These behaviors were consistent across subjects (7 of 9 subjects). The hip
frontal plane, and hip and knee sagittal plane kinematics were unaffected by
removal of the AFO. Finally, the minimum toe clearance was not affected by the
removal of the AFO (1.39 cm+/-0.62 SD vs. 1.27 cm+/-0.47 SD, p>0.05). Taken
together, these findings suggest that pelvic obliquity is the primary
compensatory degree of freedom utilized to achieve toe clearance in response to
impaired dorsiflexion in the stroke population. We propose that this degree of
freedom is exploited as it is not constrained by synergistic torque coupling of
the lower limb.

Langue : ANGLAIS