Effect of botulinum toxin type A on gait of children who are idiopathic toe-walkers.

The purpose of this study was to determine the effects of botulinum toxin type A treatment on ankle muscle activity during gait of children who are idiopathic toe-walkers. Five children who were idiopathic toe-walkers with a mean age was 4.34 years participated. Gait of the subjects was evaluated prior to, 20 days following, and 12 months following bilateral botulinum toxin type A injection of the gastrocnemius and soleus muscles. Subjects received physical therapy following the 20-day evaluation. Dependent variables were type of foot contact pattern and duration of swing-phase tibialis anterior activity and onset of stance-phase gastrocnemius relative to ground contact. Prior to treatment 51% of foot contacts were with the toe (heel just off the ground) or were digitigrade, while the remaining contacts were flat foot or heel strike. At approximately 20 days following treatment, only 8% of foot contacts were toe contact or digitigrade. Prior to treatment, mean gastrocnemius onset was 30 ms prior to foot contact and the duration of swing-phase tibialis anterior was only 345 ms. Following treatment (and a more normal foot contact pattern), mean gastrocnemius onset followed ground contact by 36 ms and tibialis anterior duration increased through terminal swing and into the loading response. The posttreatment improvement was maintained at 12-month follow-up. It appears that botulinum toxin type A treatment normalizes the ankle EMG pattern during gait and a more normal foot-strike pattern is obtained. These data are discussed in terms of a neuromotor rationale for the rehabilitation of children who are idiopathic toe-walkers to maintain posttreatment improvements.