Effects of botulinum toxin-A on gait velocity, step length, and base of support of patients with dynamic equinovarus foot.

OBJECTIVE

The aim of this study was to identify if botulinum toxin type A is a drug able to modify walking velocity, step length, and width of the base of support of adult patients with dynamic equinovarus foot deformity resulting from upper motor neuron syndrome.

DESIGN

This retrospective study analyzed data from 20 patients' files selected from 448 consecutive charts. The main inclusion criteria were the presence of dynamic equinovarus foot deformity due to upper motor neuron syndrome, age between 20 and 80 yrs, evaluation of temporospatial parameters of gait by the Gait Mat II before and 4 wks after botulinum toxin type A injection to the calf muscles, and the ability to walk barefoot, unassisted, and without braces. For data analysis, based on walking velocity, we divided the patients into two groups, slow walking velocity (0.18-0.49 m/sec) and medium walking velocity (0.50-0.99 m/sec).

RESULTS

Width of the base of support was significantly reduced after botulinum toxin type A treatment, both for the affected (P < 0.005) and the unaffected limbs (P < 0.002), in the group of subjects walking at medium velocity. Walking velocity or step length of either group of patients was not significantly modified by botulinum toxin type A treatment.

CONCLUSIONS

Based on this study, a significant effect of botulinum toxin type A on width of the base of support is evident and seems to be the result of a better position of the affected foot during the stance phase of locomotion leading to increased body stability and consequent reduction of width of the base of support of the unaffected limb. No change was evident in step length or walking velocity for this patient population.