Peroneal Nerve Injury: Symptoms, Types, Causes and Treatment

Peroneal nerve injury is a common neurological problem that can significantly impact a person's ability to walk and perform daily activities. The peroneal nerve (also known as the fibular nerve) is especially vulnerable due to its superficial position near the knee, making it prone to trauma and compression. Understanding the symptoms, types, causes, and treatment options is crucial for timely diagnosis and optimal recovery. This article provides a comprehensive guide based on current research.

Symptoms of Peroneal Nerve Injury

Peroneal nerve injuries can manifest in a variety of ways, affecting both movement and sensation. Recognizing these symptoms early is essential for effective management and prevention of further complications.

Motor	Sensory	Gait	Source
Foot drop	Numbness	Steppage gait	1 2 4 5 9
Weak dorsiflexion	Tingling/burning	Falls risk	3 4 5
Weak eversion	Loss of sensation	Foot slap	2 4 5
Toe extension weakness	Pain (occasionally)	Instability	4 5 9

Table 1: Key Symptoms

Motor Symptoms

The most classic symptom is foot drop, where patients have difficulty lifting the front part of the foot, causing it to drag or slap the ground. This occurs due to weakness or paralysis of the muscles responsible for dorsiflexion (lifting the foot upwards) and eversion (turning the sole outward) 1 2 4 5 9. Toe extension weakness may also be present.

Those affected often develop a steppage gait, lifting their knee higher than usual to avoid tripping over the foot. This altered gait can lead to instability and an increased risk of falls 3.

Sensory Symptoms

Sensory changes are also common. These may include:

• Numbness or reduced sensation over the outer (lateral) aspect of the lower leg and the top (dorsum) of the foot.
• Tingling or burning sensations, sometimes described as "pins and needles."
• In some cases, pain may accompany sensory loss, although this is less prominent than with other nerve injuries 4 5.

Gait and Other Functional Issues

• Due to motor and sensory loss, patients are at increased risk of falls, especially when walking on uneven surfaces 3.
• The foot may slap the ground with each step, known as foot slap.
• Chronic cases can result in muscle atrophy or permanent deformities if untreated 4 5.

Types of Peroneal Nerve Injury

Peroneal nerve injuries vary not just in severity, but also in the specific branch or location affected. Understanding these distinctions can guide both diagnosis and treatment.

Type	Description	Presentation	Source
Neuropathy	General dysfunction	Weakness, numbness	5 4
Palsy	Complete/partial paralysis	Foot drop, sensory loss	2 4 7
Entrapment	Compression at key sites	Variable symptoms	5 2
Branch-specific	SPN or DPN involvement	Sensory vs. motor focus	5 6

Table 2: Injury Types

Neuropathy vs. Palsy

• Peroneal neuropathy refers broadly to dysfunction in the nerve, which can be due to trauma, compression, or metabolic factors. Symptoms range from mild to severe 5 4.
• Peroneal nerve palsy is a more severe form, involving partial or complete loss of nerve function—often manifested as foot drop and more extensive sensory changes 2 4 7.

Entrapment Syndromes

Entrapment describes compression of the nerve along its course. The most common site is at the fibular (peroneal) head, where the nerve is especially superficial and prone to injury 2 5. Entrapment can also occur as the superficial peroneal nerve (SPN) exits the lateral compartment of the leg or as the deep peroneal nerve (DPN) passes beneath the extensor retinaculum at the ankle 5 6.

Branch-specific Injuries

• Common Peroneal Nerve (CPN): Most frequently injured at the fibular head. Motor and sensory deficits are both common 5.
• Superficial Peroneal Nerve (SPN): Primarily affects sensation on the outer lower leg and dorsum of the foot. May present with numbness or burning without significant motor loss 6.
• Deep Peroneal Nerve (DPN): Mostly affects foot dorsiflexion and toe extension, with sensory loss in the web space between the first and second toes 5.

Acute vs. Chronic Injuries

• Acute injuries are sudden (e.g., trauma, laceration, acute compression) and may present dramatically.
• Chronic injuries develop over time and may be associated with slow-growing masses, habitual leg crossing, or metabolic conditions 1 4 5.

Causes of Peroneal Nerve Injury

The peroneal nerve’s anatomy makes it susceptible to several different types of injury. Some causes are dramatic and clear, while others can be subtle and develop over time.

Cause	Mechanism	Risk Factors/Examples	Source
Trauma	Direct injury, laceration	Fractures, knee dislocation, ski accidents	1 4 8 9
Compression	External/internal pressure	Prolonged leg crossing, tight casts, masses	2 3 5
Iatrogenic	Medical intervention	Surgery, injections	10 11
Metabolic	Systemic disease	Diabetes, neuropathy	1 3 5
Sports	Repetitive motion, acute	Skiing, snowboarding	9

Table 3: Common Causes

Traumatic Causes

Trauma is a leading cause of peroneal nerve injury:

• Fractures and dislocations around the knee, especially of the fibular head, can directly injure the nerve 1 4 8.
• Lacerations (such as from sharp ski edges) can sever the nerve, resulting in immediate and severe symptoms 9.
• Surgical trauma during procedures like total knee arthroplasty or external fixator placement can injure the nerve 7 10 11.

Compression and Entrapment

The peroneal nerve can also be compressed by:

• External pressure: Commonly from habitual leg crossing, squatting, or tight casts/braces 2 3 5.
• Mass lesions: Such as cysts, tumors, or hematomas pressing against the nerve 1 2.
• Prolonged immobilization: Patients in bed for long periods or in certain positions are at risk 2 5.

Iatrogenic Causes

Medical interventions can cause injury:

• Surgical procedures around the knee, hip, or leg may inadvertently damage the nerve 10 11.
• Injections or other interventions near the nerve can also result in injury 10.

Metabolic and Systemic Conditions

Certain medical conditions increase vulnerability:

• Diabetes is a major risk factor due to its association with peripheral neuropathy 1 3 5.
• Other metabolic syndromes can also contribute to nerve dysfunction 1 5.

Sports and Activity-Related Injuries

• Skiing and snowboarding: Sharp equipment and high-speed falls have led to an increase in peroneal nerve lacerations 9.
• Repetitive stress from certain sports or occupations can contribute to chronic nerve irritation 9.

Anatomical Variations

• Variations in the superficial peroneal nerve’s course can increase susceptibility to iatrogenic injury during procedures 6.

Treatment of Peroneal Nerve Injury

Treatment approaches depend on the underlying cause, severity, and duration of the injury. Early intervention is crucial for maximizing recovery.

Approach	Indications	Outcomes/Notes	Source
Conservative	Mild/moderate, early cases	Bracing, PT, meds; often effective	2 5 7
Surgical Decompression	Entrapment, masses, refractory cases	Good outcomes; prompt surgery for acute laceration	2 5 10 11
Nerve Repair/Grafting	Severe trauma, laceration	Variable success; best if early and with short grafts	8 10 11
Tendon Transfer	Failed nerve repair; chronic cases	Restores foot lift; improves function	8 10 11

Table 4: Treatment Strategies

Conservative Management

First-line treatment for most cases, especially with mild deficits or unclear etiology:

• Activity modification: Avoid pressure or repetitive trauma to the nerve.
• Bracing: Ankle-foot orthoses (AFO) can help with foot drop and prevent falls 2 5 7.
• Physical therapy: Strengthening and stretching to maintain mobility and prevent contractures 2 5.
• Medications: For pain control and neuropathic symptoms 2 5.
• Observation: Some acute compression injuries resolve spontaneously with conservative measures 5 7.

Surgical Decompression

• Indicated for compressive lesions that do not improve with conservative treatment, or if a mass (such as a cyst or tumor) is present 2 5.
• Prompt decompression is critical for acute nerve lacerations or severe entrapment 2 10 11.
• Outcomes are generally favorable, especially with early intervention 2 10 11.

Nerve Repair and Grafting

• For open injuries or cases where the nerve is severed, direct repair or grafting with autologous nerve tissue (often sural nerve) is considered 8 10 11.
• Prognosis depends on the timing and length of the graft; short grafts (<6 cm) and early intervention yield better results 8 10.
• Recovery after nerve grafting is often limited; only a minority regain full function, especially if surgery is delayed 8 10.
• Combined procedures (nerve repair and tendon transfer) show improved outcomes 11.

Tendon Transfer

• For patients with irreversible nerve injury or failed nerve repair, transferring a functioning tendon (such as the tibialis posterior) can restore active dorsiflexion and improve gait 8 10 11.
• Early correction of muscle imbalances may also favor nerve regeneration 11.

Emerging and Adjunct Treatments

• Microsurgical decompression and percutaneous peripheral nerve stimulation are newer options, though large-scale outcome data are still lacking 5.
• Cryoneurolysis (targeted cold therapy for pain) does not seem to cause permanent motor deficits, based on animal models, but its role in humans remains investigational 12.

Rehabilitation and Prognosis

• Recovery often takes months; physical therapy is vital throughout 2 7 8.
• Prognosis is best with early diagnosis and intervention, short denervation time, and for injuries caused by sharp trauma rather than crush 8 11.
• Chronic cases may require lifelong bracing or secondary surgical interventions 7 8 10 11.

Conclusion

Peroneal nerve injury is a common yet complex condition with significant functional implications. Early recognition and tailored intervention are key to optimal outcomes.

Main Points:

• The most common symptoms are foot drop, sensory changes, and gait abnormalities, all of which can increase the risk of falls.
• Peroneal nerve injuries can be classified by severity, location, and whether they are acute or chronic.
• Causes range from trauma and compression to metabolic, iatrogenic, and sports-related injuries.
• Treatment is individualized—conservative care is often effective, but surgical intervention is needed for severe or refractory cases.
• Early intervention, especially for traumatic and compressive injuries, is associated with the best prognosis.
• For chronic or irreparable injuries, tendon transfer can restore function and independence.

Recognizing the signs and understanding the variety of causes and treatments can help ensure the best possible recovery for those affected by peroneal nerve injury.