Common Peroneal Nerve Palsy: Causes, Symptoms & Acupuncture Treatment

The common peroneal nerve is a major branch of the lower portion of the sciatic nerve. It divides into the deep peroneal nerve, superficial peroneal nerve, and cutaneous branches. Paralysis of this nerve presents with the classic symptom of foot drop.

Primary causes include compression—such as prolonged squatting at work, sitting with legs crossed for extended periods, long-term casting or bandaging of the lower limb—as well as pressure on the fibular head, laceration to the fibular head, inflammation of the common peroneal nerve, traction injury, local infection in diabetes, and toxic damage, all of which can directly or indirectly injure the common peroneal nerve and give rise to this condition.

【Diagnostic Points】

When clinical common peroneal nerve injury results in complete paralysis, the presentation includes marked foot drop, with inability to perform dorsiflexion, toe extension, abduction, and pronation. There is foot inversion, flexion of the proximal phalanges of the toes. In chronic cases, the deformity manifests as “equinovarus foot” (horse-claw foot) or a “steppage gait” (rooster gait). Atrophy of the muscles on the anterolateral aspect of the leg occurs, while the Achilles tendon reflex remains unaffected.

The sensory disturbance is located in the anterolateral aspect of the lower leg (lateral sural cutaneous nerve), the dorsum of the foot and the second interdigital space (medial dorsal cutaneous nerve and intermediate dorsal cutaneous nerve), and involves the dorsal lateral cutaneous nerve and dorsal medial cutaneous nerve of the second toe.

Isolated injuries of the deep or superficial fibular nerve are rare. In the case of isolated deep fibular nerve injury, paralysis of the anterior tibial muscle group occurs, resulting in impaired dorsiflexion of the foot and elevation of its medial border, along with foot drop and slight abduction. Due to paralysis of the extensor digitorum longus and extensor hallucis longus, and the antagonistic action of the lumbricals and interossei, flexion of the proximal phalanges of the toes (plantar flexion) appears. Sensory deficits from deep fibular nerve injury are confined to the first interdigital space.

Isolated injury to the superficial peroneal nerve causes paralysis of the gastrocnemius and peroneus brevis muscles, resulting in impaired foot abduction and elevation of the lateral border of the foot, hence foot inversion and drooping of the lateral border (pes varus). There is sensory disturbance over the first interdigital space and the dorsum of the foot along the lateral border.

Treatment

I. Acupoints and Needling Techniques

1. Common Peroneal Nerve Point (affected side): Located on the lower lateral aspect of the knee, 0.5 cun inferior and posterior to the fibular head, at the lateral border of the fibula. A 30-gauge, 2-cun filiform needle is selected. After routine local disinfection, insert perpendicularly to a depth of approximately 1.8 cun. Needling sensation: local distension and pain, or a radiating sensation toward the dorsum of the foot.

2. ST36 (Zusanli) on the affected side: Located 3 cun below ST35 (Dubi), one finger-width (middle finger) lateral to the anterior border of the tibia. Use a #30 gauge, 2 cun filiform needle. After routine local disinfection, insert perpendicularly approximately 1.8 cun. Needling sensation: local distension and pain, or radiation to the dorsum of the foot.

3. LR2 (Xingjian) (affected side): Located on the dorsum of the foot, in the depression proximal to the web margin between the 1st and 2nd toes. Using a 30-gauge, 2-cun filiform needle, after routine local disinfection, insert obliquely upward to a depth of approximately 1.8 cun. Sensation: local distension and pain.

4. ST44 (Neiting) (affected side): Located on the dorsum of the foot, at the junction of the web between the 2nd and 3rd toes. Using a 30-gauge, 2-cun filiform needle, perform routine local disinfection. Insert obliquely upward to a depth of approximately 1.8 cun. Needle sensation: local distension and pain.

II. Methods

The patient takes a seated position. The aforementioned acupoints are needled according to the method and connected to electroacupuncture. The needles are retained for 40 minutes and then removed. Treatment is administered once daily, with 10 sessions constituting one course. A 5-day rest is taken before the next course.

Commentary

For common peroneal nerve injury, applying the above method yields favorable outcomes in patients without nerve rupture, without muscle atrophy, with mild injury, and with a short duration of injury. If the injury involves prolonged compression with muscle atrophy, a longer treatment period is required, though some effect can still be observed. In cases of nerve rupture, muscle atrophy typically occurs rapidly, and the above method yields unsatisfactory results—only partial restoration of muscle tone may be achieved; early surgical intervention should be considered. During treatment, it is essential first to strengthen the patient’s confidence in recovery, while simultaneously incorporating exercises and gait correction, which can help facilitate and promote early rehabilitation of the affected limb.

Etiology of Common Fibular Nerve Palsy

The causes of common fibular nerve palsy are diverse, yet most share a common mechanism of mechanical compromise to the nerve at the fibular neck. The nerve is particularly vulnerable at this anatomical site because it is superficial, fixed, and lacks protective epineurial soft tissue. Compression is the predominant etiology, arising from prolonged squatting—frequently seen in agricultural workers, gardeners, or during certain religious practices—or from habitual leg crossing. Additionally, iatrogenic compression from tight bandages, long leg casts, or improperly positioned surgical stirrups can precipitate neuropathy. External compression may also result from space-occupying lesions such as a Baker’s cyst, proximal tibiofibular joint ganglion, or hematoma. Traumatic causes include direct contusion, laceration over the fibular head, or fracture of the proximal fibula. Inflammatory conditions (e.g., diabetic neuropathy, vasculitis) and prolonged immobilization in bedridden patients further contribute to nerve dysfunction. It is crucial to differentiate these mechanical and systemic triggers, as prognosis hinges on the nature and duration of the insult.

Clinical Presentation and Diagnostic Approach

A thorough understanding of common peroneal nerve palsy symptoms and diagnosis is essential for timely intervention. The hallmark is foot drop, an inability to dorsiflex and evert the foot, leading to a characteristic steppage gait (slapping gait). Patients may also report numbness, tingling, or burning pain over the dorsum of the foot and the lateral aspect of the lower leg. On physical examination, weakness of the tibialis anterior, extensor hallucis longus, and peroneal muscles is evident, while ankle plantarflexion and inversion remain intact—a key feature distinguishing peroneal palsy from L5 radiculopathy. Sensory loss is confined to the superficial and deep peroneal nerve territories. Diagnosis is confirmed by electrodiagnostic studies: nerve conduction studies reveal reduced amplitude or conduction block at the fibular head, and electromyography shows denervation potentials in affected muscles. Imaging (ultrasound or MRI) may identify compressive lesions. The differential diagnosis includes sciatic neuropathy, lumbar disc herniation, and motor neuron disease. Early, accurate diagnosis guides management and improves outcomes.

Management Strategies for Foot Drop

Effective common peroneal nerve palsy foot drop treatment depends on the underlying cause and severity. Conservative measures are first-line for compressive or mild cases: removing the offending agent (e.g., discontinuing leg crossing), physical therapy to maintain ankle range of motion and strengthen residual muscles, and ankle-foot orthoses (AFO) to prevent foot drop during gait and reduce fall risk. Neuropathic pain can be managed with gabapentin or tricyclic antidepressants. For patients with persistent weakness beyond 3–6 months, surgical intervention may be considered. Nerve decompression at the fibular neck is indicated for documented entrapment or compressive lesions. In cases of laceration or severe injury, nerve repair (direct neurorrhaphy or graft) may be attempted if the nerve ends are approximated. For chronic, non-recoverable foot drop, tendon transfer procedures (e.g., posterior tibialis tendon transfer) can restore active dorsiflexion. Emerging treatments include nerve transfers (e.g., from the tibial nerve) and functional electrical stimulation. Close follow-up with serial electrodiagnostics is recommended to monitor recovery. Prognosis is favorable if the palsy is due to brief compression, whereas traumatic or prolonged neuropathies carry a guarded outlook.