Case Description:
A 64-year-old female with history of right MCA stroke 15 months ago with residual left-sided weakness presents with a one-year complaint of hyperextension of her left great toe with associated pain. She reported regaining the ability to walk several weeks following her stroke with subsequent development of great toe hyperextension. She had two previous injections of her left extensor hallucis longus (EHL) (50, and 100 units of Onabotulinum toxin A, respectively) at an outside facility without improvement. The patient was referred to our clinic for possible phenol neurolysis for EHL overactivity. 

Results:
On exam, patient had hyperextension of her left great toe of 60 degrees in a resting supine position. Walking with a cane, she had full foot contact on the left during stance phase, but the left ankle then became plantarflexed (~30 degrees) and great toe hyperextended. Needle electromyography showed spontaneous firing greatest in the left gastrocnemius and EHL muscles with moderate activity of soleus and faint activity of tibialis anterior. A diagnostic lidocaine block of her tibial nerve was performed, resulting in full foot contact with the floor and greatly reduced great toe hyperextension during stance phase. 

Discussion:
Given the gradual development of great toe hyperextension, needle EMG findings and the patient’s responses to the nerve block, EHL overactivity and great toe hyperextension are likely a maladaptive reaction to spastic foot drop and compensatory to provide ankle and foot stability for weight bearing on the metatarsophalangeal joint.

Conclusions:
This case emphasizes the importance of carefully selecting muscles based on the mechanical effects of spastic muscles on ankle and foot positioning during walking when treating post-stroke spasticity with botulinum toxin.

Great Toe Hyperextension As a Result of Maladaptive Compensation for Spastic Foot Drop in Post-Stroke Hemiplegic Gait