What is the cause of foot drop (peroneal nerve palsy)?

From the Guidelines

Foot drop, also known as peroneal nerve palsy, is primarily caused by nerve damage, particularly to the peroneal nerve, which can result from various factors including trauma, compression, or peripheral neuropathy. The peroneal nerve controls the muscles responsible for lifting the front part of the foot, and damage to this nerve can lead to weakness or paralysis of these muscles, causing the foot to drag while walking. According to the most recent guidelines, individuals with peripheral neuropathy, which can contribute to foot drop, should take preventive measures such as wearing proper footwear and examining their feet daily to detect lesions early 1.

Causes and Risk Factors

• Nerve damage or compression, particularly of the peroneal nerve
• Peripheral neuropathy, which can be caused by diabetes, among other conditions
• Trauma or injury to the leg or foot
• Certain medical conditions, such as multiple sclerosis or Charcot-Marie-Tooth disease

Management and Treatment

• Ankle-foot orthosis (AFO) brace to hold the foot in a normal position during walking
• Physical therapy exercises to strengthen the affected muscles and improve range of motion, such as toe raises, ankle rotations, and resistance band exercises
• Electrical stimulation therapy for temporary foot drop
• Surgical interventions like tendon transfers or nerve grafting for permanent or severe cases

Importance of Early Intervention

Early diagnosis and treatment of foot drop are crucial for preventing further complications, such as falls and mobility issues, and for maintaining independence and quality of life. As noted in recent standards of care, moderate-intensity walking and proper footwear can improve outcomes in individuals with peripheral neuropathy 1. Therefore, it is essential to seek medical attention promptly if symptoms of foot drop occur.

From the Research

Causes of Foot Drop

The causes of foot drop (peroneal nerve palsy) can be varied and include:

• Injury to the common peroneal nerve, which innervates ankle joint and foot extensors 2
• Sciatic nerve injury 2, 3
• Lumbar plexopathies 2
• L4/L5 radiculopathy 2, 3
• Central nervous system related neuropathies (anterior horn cell disease, brain tumor) 2
• Compartment syndromes of the lower leg 2
• Chiari malformation type 1 4
• Disturbance at any central or peripheral location along the motor neural pathway that terminates in the dorsiflexor muscles of the foot, or at multiple locations in series 3

Common Causes

The most common causes of foot drop are:

• L5 radiculopathy 3
• Peroneal nerve injury 2, 3

Other Factors

Other factors that can contribute to foot drop include:

• Neurogenic drop foot, which may be caused by central or peripheral lesions of the nervous system 5
• Spastic drop foot, which persists as a residual long-term complication after stroke in about 14% of patients 5