How effective is physical therapy for gait muscle activity in hemiparetic patients who receive botulinum toxin injections?

[BACKGROUND] Administration of botulinum neurotoxin A (BoNT-A) to the ankle plantar flexors in patients with hemiplegia reduces the strength of knee extension, which may decrease their walking ability. Studies have reported improvements in walking ability with physical therapy following BoNT-A administration. However, no previous studies have evaluated from an exercise physiology perspective the efficacy of physical therapy after BoNT-A administration for adult patients with hemiplegia.

[AIM] To investigate the effects of physical therapy following BoNT-A administration on gait electromyography for patients with hemiparesis secondary to stroke.

[DESIGN] Non-randomized controlled trial.

[SETTING] Single center.

[POPULATION] Thirty-five patients with chronic stroke with spasticity were assigned to BoNT-A monotherapy (N.=18) or BoNT-A plus physical therapy (PT) (N.=17).

[METHODS] On the paralyzed side of the body, 300 single doses of BoNT-A were administered intramuscularly to the ankle plantar flexors. Physical therapy was performed for 2 weeks, starting from the day after administration. Gait electromyography was performed and gait parameters were measured immediately before and 2 weeks after BoNT-A administration. Relative muscle activity, coactivation indices, and walking time/distance were calculated for each phase.

[RESULTS] For patients who received BoNT-A monotherapy, soleus activity during the loading response decreased 2 weeks after the intervention (P<0.01). For those who received BoNT-A+PT, biceps femoris activity and knee coactivation index during the loading response and tibialis anterior activity during the pre-swing phases increased, whereas soleus and rectus femoris activities during the swing phase decreased 2 weeks after the intervention (P<0.05). These rates of change were significantly greater than those for patients who received BoNT-A monotherapy (P<0.05).

[CONCLUSIONS] Following BoNT-A monotherapy, soleus activity during the stance phase decreased and walking ability either remained unchanged or deteriorated. Following BoNT-A+PT, muscle activity and knee joint stability increased during the stance phase, and abnormal muscle activity during the swing phase was suppressed.

[CLINICAL REHABILITATION IMPACT] If botulinum treatment of the ankle plantar flexors in stroke patients is targeted to those with low knee extension strength, or if it aims to improve leg swing on the paralyzed side of the body, then physical therapy following BoNT-A administration could be an essential part of the treatment strategy.