Page 57 - Maximizing the efficacy of ankle foot orthoses in children with cerebral palsy

The shank-to-vertical angle
Statistics
The effects of the different AFO-FC conditions on the SVA, joint flexion-extension angles and net moments, and Shank-to-AFO angle were analyzed for statistical significance using a two-way repeated measures analysis of variance (ANOVA) with two within-subject factors (i.e. heel height (three levels) and footplate stiffness (two levels)), using Bonferroni post-hoc adjustments (α=5%). Statistical analyses were done using IBM SPSS Statistics, version 20 (SPSS Inc, Chicago, USA).
reSULtS SVa
III
The SVA at midstance significantly increased with increasing heel height (see Figure 3.3A). The SVA during walking (mean (SD) walking speed: 0.96 (0.07) m·s-1) was larger in all heel height conditions compared to the imposed SVA of 5°, 11° and 20° in static position (see Table 3.1). Footplate stiffness had no effect on SVA, and also no interaction effect of heel height and footplate stiffness on SVA was found (F=0.71, p=0.505) (see Figure 3.3A).
Knee joint
The effects of the AFO-FC manipulations were most prominent at the knee joint, with the knee flexion angle and internal knee extensor moment at midstance significantly increasing with increasing heel height (see Table 3.1). The stiff footplate tended to decrease the knee flexion angle and internal knee extensor moment at midstance, although this was only significant for the internal knee extensor moment. An interaction effect of heel height and footplate stiffness on the knee flexion angle (F=3.54, p=0.050) and internal knee extensor moment (F=4.06, p=0.035) was found, indicating an inhibiting effect of the stiff footplate for the low and high heel height conditions, but not for the medium heel height condition (see Table 3.1; Figure 3.3B-C).
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