Botulinum toxin type A (BoNT-A) injection is an effective treatment for lower-limb spasticity and should be offered as first-line treatment for focal manifestations. Although its possible role has been hypothesized, the efficacy of electrical stimulation (ES) of antagonists of the injected muscles for improving clinical outcome after BoNT-A injection remains to be established.

This randomized single-blind pilot study aimed to investigate the efficacy of ES of antagonist muscles as adjunct treatment after BoNT-A injection to plantar flexor muscles in hemiplegic patients with spastic equinus foot.

After BoNT-A injection at triceps surae, patients were randomly allocated to 2 groups: group 1, single ES session on injected muscles plus 5 sessions of ES on antagonist muscles, and group 2, single ES session on injected muscles alone. Both groups underwent daily physical therapy for 60min for 2 weeks (5 days/week). Assessments were performed before treatment (T₀) and at 10 days (T₁), 20 days (T₂), and 90 days (T₃) after treatment. Our primary outcome was gait velocity at a comfortable speed at T₂ (10-m walk test [10MWT]). The following were secondary outcomes: triceps surae spasticity (Modified Ashworth Scale), ankle passive range of motion (pROM), strength of tibialis anterior muscle, and 2-min walk test (2MWT).

The 30 patients enrolled were randomly allocated to the 2 groups: 15 in group 1 and 15 in group 2. At T₁, T₂ and T₃, both groups showed a significant reduction in muscle tone and an increase in ankle pROM (P<0.05). At T₂ and T₃, both groups showed a significant increase in 10MWT and 2MWT. The groups did not significantly differ in tibialis anterior strength or primary or secondary outcome measures.

ES of antagonist muscles does not improve clinical outcomes in the post-stroke spastic equinus foot after BoNT-A injection.