Fibular (peroneal) neuropathy
Fibular (common peroneal) neuropathy is a compressive mononeuropathy at the fibular head/neck causing foot drop with weak ankle/toe dorsiflexion and eversion, dorsal foot and lateral leg sensory loss, and a preserved ankle reflex. EMG/nerve conduction studies confirm and localize the lesion, and most cases resolve with removal of the compressive cause, an ankle-foot orthosis, and physical therapy.
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What this article covers
- Overview
Fibular (common peroneal) neuropathy is a focal compressive mononeuropathy, most often at the fibular head/neck, its most common site of compression along its course.
- Epidemiology
Occurs across a wide age range wherever a susceptible position or compressive exposure is sustained, rather than in a particular demographic.
- Risk factors
Habitual or prolonged leg crossing, the single most frequently cited cause.
- Pathophysiology
Anatomic vulnerability: the common fibular nerve, one of the two terminal divisions of the sciatic nerve, winds superficially around the fibular neck directly against bone with minimal overlying soft tissue, exposing it to compression there.
- Clinical features
Foot drop: inability to dorsiflex the ankle and toes, producing a high-stepping "steppage gait" as the patient lifts the knee to clear the foot off the ground while walking.
- Differential diagnosis
Anterior compartment syndrome: compresses the deep fibular nerve, but presents with severe pain out of proportion to exam, a tense/swollen anterior compartment, and pain with passive toe flexion…
- Diagnosis
The diagnosis is confirmed by a compatible localizing exam plus electrodiagnostic testing, not clinical impression alone: findings limited to the fibular territory (weak ankle/toe dorsiflexion and…
- Management
First, identify and eliminate the compressive cause: stop habitual leg crossing, avoid prolonged squatting or kneeling, loosen or refit a tight cast, brace, or wrap at the fibular neck, and…
- Complications
Persistent or permanent foot drop with an abnormal steppage gait and increased fall risk if axonal loss is significant or the compressive cause is not corrected.
- Prognosis
Prognosis tracks the electrodiagnostic pattern: a focal demyelinating conduction block at the fibular neck without active denervation is favorable, since it reflects local demyelination that can remyelinate once compression is removed.
- Prevention
Advise against habitual or prolonged leg crossing, the single most preventable cause; counsel patients to change position rather than sustain a crossed-leg posture for an extended period.
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