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

Background and purpose: 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. Methods: 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 460 U onabotulinumtoxinA, respectively. The course of the mAS was explored during the open study phase. Results: 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). Conclusions: The study demonstrates a reduction of muscular hypertonicity in spastic pes equines with BoNT/A treatment given during the first 3 months after the lesion. Exploratory analyses of the course of muscular hypertonicity during the open phase favour earlier to later treatment.