Efficacy of Botulinum Toxin A Treatment for Pes Varus during Gait

Abstract

The efficacy of botulinum toxin A (BoNTA) injection on spasticity is usually measured using Modified Ashworth Scale (MAS), but this only evaluates muscle tone at rest and has poor reliability. There are no reports that quantitatively evaluate pes varus during walking after botulinum treatment. The purpose of this study was to evaluate the efficacy of BoNTA injection on pes varus during gait using 3-dimensional motion analysis. Twenty-four hemiplegic patients with spastic pes varus deformity during gait received BoNTA injection into lower limb muscles. MAS score, comfortable overground gait velocity, and pes varus angle during treadmill walking were evaluated before, 2, 6, and 12 weeks after the injection. Five healthy subjects were also recruited to develop the pes varus/valgus angle as a normal reference. The median MAS scores were significantly lower at 2 and 6 weeks after the injection. The maximum pes varus angle during the swing phase was significantly lower at 2, 6, and 12 weeks after the injection. It was significantly lower at 6 weeks after the injection during stance phase. The comfortable overground gait velocity was also improved after the injection. However, 2 patients experienced pain during gait and their pes varus angle increased during the follow-up period. BoNTA injection improved pes varus angle during gait. Evaluating motion in addition to spasticity at rest is recommended because improvements in limb function do not always parallel improvements in spasticity at rest.