Early botulinum toxin treatment for spastic pes equinovarus--a randomized double-blind placebo-controlled study.

Abstract

Spastic pes equinovarus is a frequent pathological posture of the lower extremity. Botulinum toxin (BoNT/A) has been successfully applied to treat lower limb spasticity. However, the best time to initiate treatment remains unclear. A beneficial effect of an early treatment has been suggested in previous studies. A single-centre double-blind randomized placebo-controlled trial was performed to investigate the efficacy of BoNT/A to reduce muscle hypertonicity at the ankle. Fifty-two patients with unilateral or bilateral spastic pes equinovarus with a modified Ashworth score (mAS) of at least 1+ after stroke, traumatic brain injury or hypoxic encephalopathy were allocated to receive either BoNT/A or placebo treatment. A second, open injection was optional at week 12. Patients received unilateral or bilateral injections with 230 or 460U onabotulinumtoxinA, respectively. The course of the mAS was explored during the open study phase. Patients who had received BoNT/A treatment had lower mAS compared with placebo at week 12 (P<0.01). During the open label phase, patients from the placebo group showed further deterioration of muscle tone despite starting from a similar baseline and receiving BoNT treatment. Spastic feet that had received BoNT/A in the first cycle had comparatively lower mAS scores over all follow-up data and at week 24 (P<0.01). The study demonstrates a reduction of muscular hypertonicity in spastic pes equines with BoNT/A treatment given during the first 3months after the lesion. Exploratory analyses of the course of muscular hypertonicity during the open phase favour earlier to later treatment.