What is the superficial peroneal nerve?
The peroneal nerve starts near your sciatic nerve at the top of your glutes (hip and butt). It travels down the back of your thigh until it reaches your knee, where the nerve wraps around the front of your leg and extends all the way down to your toes. Around your knee, your common peroneal nerve splits into two branches: the deep peroneal nerve and the superficial peroneal nerve. The deep peroneal nerve, which runs on the inside of your leg and over your ankle bone helps control function on the inside of your foot, including your big and second toe; and the superficial peroneal nerve that runs on the outside of your leg is responsible for sensation in the outer two-thirds of your leg and the top of your foot. It helps control the movement of all your other toes, allowing you to lift your toes and ankles.
What is superficial peroneal nerve entrapment?
Superficial peroneal nerve entrapment, also known as common peroneal nerve entrapment or peroneal nerve compression, is a condition where the superficial peroneal nerve, which is actually a branch of the sciatic nerve, gets compressed or entrapped. This compression can lead to various symptoms in the lower leg and foot. Many people with a peroneal nerve injury develop a foot drop, which is a walking pattern where you can’t properly flex your foot to take a step forward. Instead, you may lift one knee higher than the other when you walk.
How does superficial peroneal nerve entrapment happen?
Swelling or disfunction of the superficial nerve can result from injury, such as ankle sprains and twists leading to entrapment when the nerve becomes over-stretched. Pressure from tight footwear, a tight leg cast, or repetitive activities can also lead to nerve entrapment. Some individuals may have anatomical variations or structures or abnormal growths such as a tumor or a blood clot near the nerve that may contribute to nerve compression. Some people develop a peroneal nerve injury after a leg or knee surgery, such as a knee replacement or hip replacement.
Injuries, such as direct blows or fractures, can cause compression of the superficial peroneal nerve.
- Ankle fracture
- Fibula fracture, a break in the long bone on the outside of your lower leg
- Knee dislocation.
- Knee fracture -If you dislocate your knee, there’s a good chance you could develop a peroneal nerve injury. Up to 2 in 5 people who dislocate their knee have a peroneal nerve injury.
What are some common signs of superficial peroneal nerve entrapment?
A common sign of a peroneal nerve injury is the development of a foot drop, the inability to move your foot, the inability to flex your toes or ankles upward (dorsiflexion). The loss of sensation in your shin or the top of your foot, or pain in your foot or lower leg, numbness, tingling in the top of the foot, or a sensation of pins-and-needles and weakness can also alert you to a possible peroneal nerve injury.
Anyone can develop a peroneal nerve injury. But if you have certain health conditions or injuries, you may be more prone to developing it:
- Anorexia nervosa
- Charcot-Marie-Tooth disease
- Inflammatory conditions, such as rheumatoid arthritis or lupus
- Low body mass index (BMI)
- Type 2 diabetes
Your risk also increases if you often sit with your legs crossed at the knee, have your leg in a cast or are on bed rest.
How is it diagnosed?
Always consult a healthcare professional for an accurate diagnosis and personalized treatment plan. To diagnose superficial peroneal nerve entrapment, a healthcare professional will typically perform a thorough physical examination, focusing on the leg and foot. They may also inquire about the patient's medical history and any recent injuries. Additional diagnostic tests that can help confirm the diagnosis may be needed to rule out other conditions, such as:
- Electromyography (EMG) to evaluate how your muscles react to nerve stimulation.
- Nerve Conduction Studies (NCS) to measure how electrical impulses run through your nerves. These tests can evaluate nerve function and identify the site and severity of the nerve compression.
- Imaging tests such as a CT scan, ultrasound or MRI. These imaging studies can help visualize any structural abnormalities, such as tumors, cysts, or bony changes, which might be causing the nerve compression.
- Magnetic resonance (MR) neurography, a specialized MRI to get a better picture of your nerves.
How do you treat superficial peroneal nerve damage?
The treatment for superficial peroneal nerve entrapment depends on the underlying cause and the severity of the condition. Conservative options may include:
- Shoe inserts, such as splints, braces or custom orthotics to help you walk with a proper gait and alleviate pressure on the nerve.
- Gait training to teach you to walk without foot drop.
- Rest the foot.
- Reduce activities that exacerbate the symptoms to aid the healing process.
- Over-the-counter or prescription pain medications can help alleviate pain and discomfort.
- Physical therapy: Specific exercises can improve nerve mobility and strengthen surrounding muscles.
- Corticosteroid injections: In some cases, injecting corticosteroids around the affected nerve can help reduce inflammation and relieve symptoms.
What happens if I don't start to get better?
For many people, symptoms improve or disappear completely with nonsurgical treatment, but if conservative measures fail to improve the condition, surgical intervention may be considered to repair the nerve or release the nerve from compression and remove any offending structures. Sometimes donor tissue is used to replace a severely deteriorated nerve. Recovery time from surgery varies. Generally, for the first six weeks following surgery you’ll limit your activities. After six weeks, you can start slowly to increase activity. Full recovery usually takes around three to four months.
Are there ways to prevent superficial peroneal nerve damage?
There’s no guaranteed way to prevent a peroneal nerve injury. However, you can lower your risk by changing some habits, such as:
- Avoid sitting with crossed legs
- Reduce activities that put pressure on your knee, especially at the side or back of your knee.
- Seek treatment for leg injuries or leg numbness right away.
The prognosis for superficial peroneal nerve entrapment varies depending on the severity, the cause, and how early the condition is diagnosed and treated. In many cases, with proper management and treatment, symptoms can improve, and individuals can regain normal function. However, in some chronic or severe cases, complete resolution of symptoms may not be possible.
Early recognition and prompt treatment often lead to better outcomes. It's essential to seek medical attention if you experience persistent pain, weakness, or numbness in the lower leg or foot, as these could be signs of nerve entrapment or other underlying conditions that require evaluation and management.
To learn more about other potential causes of foot pain click here.