Stroke may result in lower extremity spasticity, which interfere with motor voluntary function and activities of daily living. Botulinum toxin type A (BTX-A) has been shown to improve lower extremity spasticity of stroke patients. There are no researches to compare the efficiency of BTX-A injection by different guidance methods in the deep muscles of lower extremity for stroke patients. The aims of investigator's study were to compare the effectiveness of BTX-A injection by different guidance methods (palpation of anatomical landmarks, ultrasonography direct) in deep spastic muscles of lower extremity for stroke patients with varus spasticity and spastic claw toes , and to study the correlation between muscles spasticity and elastic properties by the sonoelastography/acoustic radiation force impulse imaging and follow the change of elastic properties in spastic muscles after BTX-A injection. We will enroll 80 hemiplegic stroke patients with varus spasticity / spastic claw toes and duration more than 6 months. Under different guidance methods (palpation of anatomical landmarks, electric stimulation, ultrasonography direct and indirect methods), BTX-A will be injected to the flexor digitorum longus and posterior tibialis muscles. If the patients have moderate hallucis spasticity, flexor hallucis longus muscle will be injected. The BTX-A dose is 50 units for each muscle. Outcome measures include Modified Ashworth Scale, Brunnstrom stage, muscle power, range of motion, the visual analog scale of pain, Stroke Impact Scale, Barthel index and lower extremity function tests, balance test, Goal Attainment Scale, sonoelastography and acoustic radiation force impulse imaging. All the assessments will be performed before BTX-A injection and followed up at 1 months, 2 months, 3 months and 6 months after injection. After performing all the assessments, investigator will investigate the efficiency of BTX-A by different guidance methods.

Stroke may result in lower extremity spasticity, which interfere with motor voluntary function and activities of daily living. Botulinum toxin type A (BTX-A) has been shown to improve lower extremity spasticity of stroke patients. There are no researches to compare the efficiency of BTX-A injection by different guidance methods in the deep muscles of lower extremity for stroke patients. The aims of investigator's study were to compare the effectiveness of BTX-A injection by different guidance methods (palpation of anatomical landmarks, electric stimulation, ultrasonography direct and indirect methods) in deep spastic muscles of lower extremity for stroke patients with varus spasticity and spastic claw toes , and to study the correlation between muscles spasticity and elastic properties by the sonoelastography/acoustic radiation force impulse imaging and follow the change of elastic properties in spastic muscles after BTX-A injection. We will enroll 80 hemiplegic stroke patients with varus spasticity / spastic claw toes and duration more than 6 months. Under different guidance methods (palpation of anatomical landmarks, electric stimulation, ultrasonography direct and indirect methods), BTX-A will be injected to the flexor digitorum longus and posterior tibialis muscles. If the patients have moderate hallucis spasticity, flexor hallucis longus muscle will be injected. The BTX-A dose is 50 units for each muscle. Outcome measures include Modified Ashworth Scale, Brunnstrom stage, muscle power, range of motion, the visual analog scale of pain, Stroke Impact Scale, Barthel index and lower extremity function tests, balance test, Goal Attainment Scale, sonoelastography and acoustic radiation force impulse imaging. All the assessments will be performed before BTX-A injection and followed up at 1 months, 2 months, 3 months and 6 months after injection. After performing all the assessments, investigator will investigate the efficiency of BTX-A by different guidance methods.

Two of arms:

1. ultrasonography direct-guidance: To inject Botulinum toxin type A on the spasticity lower extremity for stroke patients by Ultrasonography direct-guidance.
2. surface anatomy landmark: To inject Botulinum toxin type A on the spasticity lower extremity for stroke patients by surface anatomy landmark.

Inclusion Criteria:

• ankle varus spasticity with spasticity claw toes
• MP joint and IP joint are above Modified Ashworth Scale 1 +
• ankle varus spasticity and spasticity claw toes during walking should reach median level
• patients feel pain or uncomfortable during walking due to spasticity claw toes.
• patients never accept botox, phenol and alcohol injections before.

Exclusion Criteria:

• contracture or deformity on lower extremity
• combine other systemic disease of neurological or skelectomuscular system
• patients accepted botox, phenol, alcohol injections and operation before.
• cognition disorder or aphasia after stroke
• Flexor Digitorum Longus, posterior tibialis and Flexor pollicis longus muscle has been significant atrophy .
• systemic infection
• under medication treatment of aminioglycoside or which can change neuromuskular transmission medicine
• ankle plantarflxeor contracture during walking above median level or the sore of Modified Ashworth Scale is above 2 at rest
• allergy to botox