Pedobarometric evaluation of equinus foot disorder after injection of botulinum toxin A in children with cerebral palsy: a pilot study

The purpose of this pilot study was to evaluate the effect of treatment with botulinum toxin A (BTX-A) injections on function in children with cerebral palsy (CP) using pedobarometric data collected in a standing position. Ten children with CP (seven males, three females) participated, five with diplegia and five with hemiplegia. All children exhibited signs of unilateral dynamic equinus foot disorder and were community ambulators. Age range at the time of treatment was 6 to 13 years (mean age 9 y, SD 2.5). A comprehensive clinical examination and a pedobarometric evaluation were performed before and after BTX-A injection. All children received at least one injection in each spastic muscle. BTX-A was given to eight children unilaterally and to two children bilaterally. A maximum dose of 4 to 8 units of BTX-A per kilogram body weight was administered. In comparison with pretreatment values, the pedobarometric evaluation revealed a significant increase in the whole plantar surface area on the affected side (p < 0.05), an increase in the peak pressure value at the hindfoot on the affected side (p < 0.05), and a significant shift in the body centre of mass to the affected limb (p < 0.05) 1 month after treatment with BTX-A. A significant decrease in the peak pressure value at the hindfoot on the unaffected side was also observed. Similarly, a decrease in the modified Ashworth scale and an increase in the range of motion were observed. Thus, BTX-A produces a significant plantar surface modification and a significant shift of the body centre of mass which represents an indirect measure of postural attitude. Pedobarometric evaluation can also be useful in quantifying clinical changes after treatment with BTX-A.