Background and Purpose—Walking is an essential activity for daily life and social participation, and it is frequently limited after stroke. A lack of knee flexion during the swing phase (stiff knee) is one of the impairments that restrict walking ability among patients with hemiparetic spasticity. Our purpose was to study the effect of Botulinum toxin type A (BoNT A) injections in several spastic muscles on the impairment, activity, participation, and quality of life of patients with chronic stroke presenting with a stiff knee gait.

Methods—Twenty chronic hemiparetic poststroke patients with stiff knee gait and ability to walk on a treadmill were recruited. BoNT A was injected into several spastic muscles: the rectus femoris (200 U), semitendinosus (100 U) and triceps surae (200 U). Patients' neurological impairments (Ashworth scale, Duncan-Ely test, Stroke Impairment Assessment Set, and instrumented gait analysis), activity (ABILOCO and 10-m walking test), and participation (SATISPART-Stroke and 36-item Short-Form Health Survey) were assessed before and 2 months after the injection.

Results—BoNT A injection reduced the impairments. It improved Stroke Impairment Assessment Set (56.5 [48–63] to 56.5 [52.5 to 63]; P<0.001), reduced rectus femoris muscle tone (2 [1 to 2.5] to 0 [0 to 1]; P<0.001), and reduced semitendinosus muscle tone (1 [1 to 1.5] to 1 [0 to 1]; P<0.001). Gait analysis demonstrated increased knee flexion during the swing phase (22±19° to 27±16°; P=0.03), decreased external mechanical work (0.66±0.38 to 0.59±0.25 J kg^-1 m^-1; P=0.04), and demonstrated a lower energy cost (5.8±1.9 to 4.9±1.9 J kg^-1 m^-1; P=0.03). The patients' locomotion ability was improved (2.2±1.9 to 3.2±2.1 logits; P=0.03). The participation and quality of life remained unchanged.

Conclusions—BoNT A injections in several muscles improved the stiff knee gait and the locomotion ability in adult stroke patients.