Effect of Ankle-Foot Orthosis Alignment and Foot-Plate Length on the Gait of Adults With Poststroke Hemiplegia

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Fatone S, Gard SA, Malas BS. Effect of ankle-foot orthosis alignment and foot-plate length on the gait of adults with poststroke hemiplegia. Objective To investigate the effect of ankle-foot orthosis (AFO) alignment and foot-plate length on sagittal plane knee kinematics and kinetics during gait in adults with poststroke hemiplegia. Design Repeated measures, quasi-experimental study. Setting Motion analysis laboratory. Participants Volunteer sample of adults with poststroke hemiplegia (n=16) and able-bodied adults (n=12) of similar age. Interventions Subjects with hemiplegia were measured walking with standardized footwear in 4 conditions: (1) no AFO (shoes only); (2) articulated AFO with 90° plantar flexion stop and full-length foot-plate–conventionally aligned AFO (CAFO); (3) the same AFO realigned with the tibia vertical in the shoe–heel-height compensated AFO (HHCAFO); and (4) the same AFO (tibia vertical) with ¾ length foot-plate–¾ AFO. Gait of able-bodied control subjects was measured on a single occasion to provide a normal reference. Main Outcome Measures Sagittal plane ankle and knee kinematics and kinetics. Results In adults with hemiplegia, walking speed was unaffected by the different conditions ( P=.095). Compared with the no AFO condition, all AFOs decreased plantar flexion at initial contact and mid-swing ( P<.001) and changed the peak knee moment in early stance from flexor to extensor ( P<.000). Both AFOs with full-length foot-plates significantly increased the peak stance phase plantar flexor moment compared with no AFO and resulted in a peak knee extensor moment in early stance that was significantly greater than control subjects, whereas the AFO with three-quarter length foot-plate resulted in ankle dorsiflexion during stance and swing that was significantly less than control subjects. Conclusions These findings suggest that when an articulated AFO is to be used, a full-length foot-plate in conjunction with a plantar flexion stop may be considered to improve early stance knee moments for people with poststroke hemiplegia.