What is the best course of treatment for an adult patient with no nerve or vessel injury, who is unable to dorsiflex their great toe, and has a history of trauma, diabetes, or other conditions that could affect the nerves or muscles in the lower extremities?

Management of Inability to Dorsiflex the Great Toe in Adults with Trauma/Diabetes History

In an adult patient unable to dorsiflex the great toe without nerve or vessel injury, the primary focus should be on identifying the underlying etiology through systematic neurological assessment, followed by targeted imaging if a central or proximal nerve lesion is suspected, rather than assuming a simple peripheral nerve injury.

Initial Clinical Assessment

The inability to dorsiflex the great toe requires distinguishing between peripheral and central etiologies, as this fundamentally changes management:

• Perform a comprehensive neurological examination looking specifically for upper motor neuron signs (hyperreflexia, spasticity, Babinski sign) versus lower motor neuron findings (hyporeflexia, muscle atrophy, fasciculations) 1, 2
• Test extensor hallucis longus (EHL) strength specifically at 0-5/5 scale, as isolated EHL weakness can occur from various levels of injury 3, 2
• Assess for sensory deficits using 10-g monofilament testing with at least one additional modality (pinprick, temperature, vibration with 128-Hz tuning fork) to identify loss of protective sensation, particularly in diabetic patients 4
• Examine the entire lower extremity for foot deformities (hammertoes, prominent metatarsal heads, bunions, Charcot foot), skin integrity, and signs of neuropathy or ischemia 4

Differential Diagnosis Considerations

The location of pathology determines treatment approach:

• Central lesions (parasagittal brain tumors) can present with isolated foot drop and lower motor neuron-like findings without typical upper motor neuron signs initially 2
• Lumbar spine nerve root damage (L5 radiculopathy) affects dorsiflexion and should be considered with back pain or radicular symptoms 5
• Sciatic nerve injury at the sciatic notch causes broader deficits beyond isolated great toe dorsiflexion 5
• Common peroneal nerve injury at the fibular head is the most common peripheral cause but typically affects the entire foot, not just the great toe 6, 5
• Multiple sclerosis can masquerade as a peripheral process with painless foot drop and lower motor neuron findings 1
• Anterior compartment syndrome following trauma can cause EHL weakness, particularly after tibial injury 3

Imaging Strategy

For patients with isolated great toe dorsiflexion weakness and lower motor neuron findings, brain MRI should be considered to rule out parasagittal lesions before assuming a peripheral etiology 2:

• Brain MRI is indicated when clinical presentation is atypical or when peripheral examination doesn't clearly localize the lesion 1, 2
• Lumbar spine MRI if radicular symptoms or multiple nerve root involvement is suspected 5
• Nerve conduction studies and EMG can help differentiate between nerve root, plexus, and peripheral nerve lesions 5

Management Based on Etiology

For Diabetic Patients with Neuropathy

• Provide specialized therapeutic footwear for patients with severe neuropathy, foot deformities, or loss of protective sensation to prevent ulceration 4
• Inspect feet at every visit if evidence of sensory loss is present 4
• Educate on daily foot inspection, proper footwear (broad square toe box, padded tongue, avoiding barefoot walking), and immediate reporting of any skin breakdown 4
• Refer to foot care specialists for ongoing preventive care if there is loss of protective sensation, structural abnormalities, or history of complications 4

For Traumatic Etiologies

• Monitor compartment pressures if recent tibial trauma occurred, as anterior compartment syndrome can cause EHL weakness even with drainage 3
• Consider ankle-foot orthosis (AFO) for functional support during ambulation if weakness persists, using designs that allow greater range of motion and can be worn discretely 6
• Avoid splinting that immobilizes the limb, as this can lead to muscle deconditioning, learnt non-use, and potentially worsen symptoms 4

For Central Lesions

• Urgent neurosurgical referral if brain imaging reveals a parasagittal mass, as surgical removal can restore function (reported recovery to 3/5 strength within 6 weeks post-operatively) 2

Critical Pitfalls to Avoid

• Do not assume peripheral nerve injury based solely on lower motor neuron findings without considering central etiologies 1, 2
• Do not delay vascular assessment in diabetic patients, as absent pedal pulses or non-healing wounds require ankle-brachial index measurement and possible vascular referral 4, 7
• Avoid routine splinting as a first-line intervention, as it may increase attention to the area, promote compensatory movement patterns, and lead to deconditioning 4
• Do not overlook Charcot neuroarthropathy in diabetic patients presenting with acute onset of red, hot, swollen foot, as early diagnosis prevents deformities 4

Functional Management Strategies

While investigating etiology, implement strategies to maintain function:

• Engage in tasks promoting normal movement patterns with even weight-bearing and good alignment 4
• Use bilateral functional activities incorporating upper limbs while standing with support 4
• Employ anxiety management and distraction techniques during functional tasks 4
• Grade activities to increase affected limb use within functional contexts using normal movement techniques 4