Effect of hinged ankle-foot orthoses on standing balance control in children with bilateral spastic cerebral palsy

Abstract

Purpose: To identify the characteristics of static standing balance and its postural control mechanisms during quiet side-by-side standing and the changes in these measures whilst wearing hinged ankle-foot orthoses (AFOs) in children with bilateral spastic cerebral palsy (CP).

Materials and methods: Twenty-one children with bilateral spastic CP (6.10 +/- 1.09 year-old) and 22 typically developing (TD) children (5.64 +/- 0.49 year-old) were recruited. Pressure data were recorded while subjects with or without AFOs stood on dual force platforms and net body center of pressure (CoP) coordinates were calculated from this data. Net body CoP was traced for measuring mediolateral (ML) and anteroposterior (AP) displacement and path length per second. Correlation coefficients between parameters representing ankle, hip, and transverse body rotation strategies were also analyzed.

Results: ML and AP displacement and path length per second of the CoP trajectory were higher in children with CP compared to TD children (p < 0.05). There were no significant improvements in these parameters whilst wearing hinged AFOs. Compared to TD children, children with CP used less ankle strategy though more hip and transverse rotation strategies for postural control during quiet standing. Whilst wearing hinged AFOs, the contribution of ankle strategy was significantly increased for ML balance control in children with CP (p < 0.05).

Conclusion: Hinged AFOs for children with CP may be helpful in improving the postural control mechanisms but not the postural stability in quiet side-by-side standing.

Fig. 1

Subjects were instructed to stand in a comfortable position while barefoot with each foot on 1 force platform with their arms hanging at their sides. The center of pressure (CoP) components (x, y) corresponded respectively to mediolatearal (ML) and anteroposterior (AP) signals in the measurement system using dual force platforms. R_right and R_left are the magnitudes of vertical ground reaction forces under the right and left limbs, respectively.

Fig. 2

Examples of trajectories in typically developing (TD) child and cerebral palsy (CP) child without an ankle-foot orthosis. (A) A TD child showed packed movement within a narrow range. (B) A child with spastic CP showed movement within a wider range.