Despite the lack of consistency in AFO preference, the questionnaire responses of the children and their parents at the final test session revealed a consensus about the benefits of wearing both types of AFO. These included the relative ease in walking long distances when wearing an AFO. The children’s responses indicated that this was because of additional support provided by the AFO: “it gave me much more control over my left side” and “because it gives my foot extra support.” However, children perceived problems with AFOs, in that they sometimes rubbed or pinched at the back of the ankle or leg and were unattractive. Parents stated that their children seemed to walk better in an AFO, with “more fluidity” and with more even steps. One parent noted that her child’s calf muscle rapidly tightened when not wearing an AFO, and this led to toe dragging and tripping. Parents perceived the advantages of wearing an AFO to be maintaining muscle length, correcting foot drop, better stability and balance, and better distribution of weight leading to a decreased risk of falls. Perceived disadvantages to wearing an AFO included teasing, embarrassment, and social difficulties at school; difficulty in fitting the AFO (especially the HAFO) into shoes and purchasing suitable shoes; the AFO was hot in summer; and the child having difficulty putting the AFOs on independently. Two parents noted that jumping and hopping activities seemed to be more difficult when wearing an AFO, although 1 parent noted that this situation was improved with the HAFO. In contrast to the children (child 1 and child 3) who preferred the LAFO, the HAFO was preferred by 1 parent because the free dorsiflexion that it allowed resulted in a better walking pattern and by the other parent because it resulted in a more parallel foot placement. The third parent stated that although her child’s doctor and physiotherapist preferred the LAFO for correction of foot drop, her child (child 2) preferred the HAFO.
This study sought to determine the usefulness of the LAFO and/or the HAFO compared with a shoe-only control condition in improving weight-bearing symmetry, weight-bearing through the rear foot, and performance of functional activities. Both AFOs were successful in increasing the contact area symmetry of the hemiplegic foot (Fig. 5), suggestive of additional foot support with an AFO compared with a shoe alone. The increase in force symmetry (Fig. 6) for the LAFO suggests that only this AFO was effective in increasing weight-bearing through the hemiplegic foot, and, hence, the LAFO might be the type of AFO more likely to provide a favorable stimulus to bone mineral accrual,4 with potential for improved bone density and growth. Previous findings of kinematic studies, in which an AFO increased the time spent on the hemiplegic foot during walking,8,9 were not supported by the current study because although there was a finding of increased time in both AFO types, this only pertained to child 3 (Fig. 7).
There was no significant AFO effect on any of the measures of functional activities with their varying demands of stability and mobility. Thus, the stability afforded by the AFO did not improve the children’s abilities in balance tasks, such as 1-legged balance, and neither did the restriction to plantar flexion caused by the AFO adversely affect ability. However, this lack of AFO influence is consistent with reports from group design studies of AFO effect on walking speed,30 GMFM scores,7 Pediatric Balance Scale scores,31 and ascending and descending stairs.14 The inability to detect change using the standardized scales of the GMFM and Berg Balance Scale seems to be at odds with conclusions that such scales are responsive to change.25,26,32 In the current study, a ceiling effect was probably encountered,25,33 because the children achieved near maximum possible scores for all conditions. For some functional measures, the wide variation in the data may have increased the SD and hence the chance of a type II error. However, this possibility was minimized by the 2-SD band analysis with which there was less than a 5% chance of type II error. Furthermore, even if the study lacked power, differences were so small that they were unlikely to be clinically significant.
Overall, the findings of the current study lend some support to the effectiveness of the LAFO and the HAFO in improving weight-bearing through the hemiplegic leg and through the rear foot during walking and possibly in assisting with push off. Although both AFO types provide foot support, the LAFO supported the rear foot more than the HAFO. Whether an increase in forefoot force is a desirable AFO outcome for children with hemiplegia is uncertain. Neither type of AFO assisted with functional ability, perhaps because of ceiling effects on the measures used. Important information about AFO effect on function might be obtained by replicating this study with younger children with emerging or less developed skill levels or with children who have more severe hemiplegia (such as at Gross Motor Function Classification System, level 2). For older children with established motor skills, it may be necessary to use more challenging measures or a patient-specific functional scale than those used. Despite the lack of consistency in AFO preference, the children and their parents had an important opinion regarding AFO type, and all perceived a benefit from greater foot support. When choosing the type of AFO, the desired effects on functional ability and weight-bearing, along with patient and parent preference and the cost of fabrication, should be considered. The findings of the current study of AFO effects indicate topics worthy of further research such as the biomechanical/physiological and functional advantages of increased foot support, the potential long-term benefit of bone growth, and the effect of increased forefoot force.
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