Peroneal Nerve Injury

What is a peroneal nerve injury?

A peroneal (pair-uh-NEE-uhl) nerve injury is dysfunction of your common peroneal nerve. The common peroneal nerve helps you feel sensations in the front and sides of your legs. It also allows you to lift your toes and ankles.

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.

Peroneal nerve injuries may cause pins-and-needles sensations, pain or weakness. You may also have a foot drop, a problem that occurs when you can’t lift your foot upward at the ankle.

What is the difference between the superficial and deep peroneal nerve?

Around your knee, your common peroneal nerve splits into two branches:

• Deep peroneal nerve: This branch runs on the inside of your leg and over your ankle bone. It helps control function on the inside of your foot, including your big and second toe.
• Superficial peroneal nerve: This branch runs on the outside of your leg. It’s 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.

Who might get a peroneal nerve injury?

Anyone can develop a peroneal nerve injury. But you are more likely to have the problem if you have certain health conditions or injuries, such as:

• Anorexia nervosa.
• Charcot-Marie-Tooth disease.
• Inflammatory conditions, such as rheumatoid arthritis or lupus.
• Knee or ankle injury.
• 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.

What causes a peroneal nerve injury?

Often, peroneal nerve injuries develop because of a traumatic injury to your knee, leg or ankle. These injuries include:

• 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. Some people develop a peroneal nerve injury after a leg or knee surgery, such as a knee replacement or hip replacement.

These injuries can also occur when something compresses (puts extra pressure on) your peroneal nerve. You might have increased pressure due to a:

• Blood clot.
• Tight leg cast.
• Tumor.

What are the symptoms of a peroneal nerve injury?

A common sign of a peroneal nerve injury is development of a foot drop. A foot drop is a distinctive way of walking. It occurs when you can’t flex your ankle to take a step forward. Instead, you may lift one knee higher than the other to raise your foot off the ground.

Other peroneal nerve injury symptoms include:

• Inability to move your foot.
• Inability to flex your toes or ankles upward (dorsiflexion).
• Loss of sensation in your shin or the top of your foot.
• Pain in your foot or lower leg.

How is a peroneal nerve injury diagnosed?

To diagnose a peroneal nerve injury, your healthcare provider examines your leg and asks you about symptoms. They may also use various tests, including:

• Imaging tests, such as a CT scan, ultrasound or MRI.
• Magnetic resonance (MR) neurography, a specialized MRI to get a better picture of your nerves.
• Electromyogram to evaluate how your muscles react to nerve stimulation.
• Nerve conduction study to measure how electrical impulses run through your nerves.

How is a peroneal nerve injury treated?

Peroneal nerve injury treatment varies based on where on the peroneal nerve the damage is and how severe it is. Your provider will likely start with nonsurgical treatments:

• Shoe inserts, such as splints, braces or orthotics, help you walk with a proper gait.
• Physical therapy can improve strength and range of motion.
• Gait training teaches you to walk without a foot drop.

In some cases, your provider may recommend surgery. During surgery, your provider may:

• Relieve pressure on the nerve.
• Repair the nerve.
• Use donor tissue to replace a severely deteriorated nerve.

How can I reduce my risk of a peroneal nerve injury?

There’s no guaranteed way to prevent a peroneal nerve injury. But you can lower your risk of severe injuries by:

• Avoiding sitting with crossed legs.
• Reducing activities that put pressure on your knee, especially at the side or back of your knee.
• Seeking treatment for leg injuries or leg numbness right away.

What can I expect if I have a peroneal nerve injury?

Recovery from a peroneal nerve injury varies depending on injury location and severity. For many people, symptoms improve or disappear completely with nonsurgical treatment.

You’re likely to make a full recovery if symptoms developed after a total knee arthroplasty. You are less likely to have symptoms go away entirely if you developed the injury after dislocating your knee.

What is the recovery time after surgery for peroneal nerve injury?

If you have surgery for a peroneal nerve injury, recovery time varies. Generally, you’ll limit activities for the first six weeks after surgery. After six weeks, you can start increasing activity levels slowly. Full recovery usually takes around three to four months.

What else should I ask my doctor?

You may also want to ask your healthcare provider:

• What is the most likely cause of a peroneal nerve injury?
• What are the treatment options?
• What could happen if I don’t get treatment for a peroneal nerve injury?
• What can I do to prevent another peroneal nerve injury?

What conditions are similar to a peroneal nerve injury?

Some neurological conditions can cause similar symptoms to peroneal nerve injuries. A healthcare provider can give you tests to determine if symptoms relate to a peroneal nerve injury or another condition.

Some of these neurological conditions include:

• Amyotrophic lateral sclerosis (ALS).
• Herniated disk.
• Multiple sclerosis.
• Parkinson disease.

A note from Cleveland Clinic

Peroneal nerve injuries affect the nerve that runs from your glutes, down the back of your thigh and around your knee, and down the front and side of your legs, to your feet. If you have a peroneal nerve injury, you may have numbness in your lower leg or foot. Many people develop a foot drop. Common treatments for peroneal nerve injuries include shoe inserts, physical therapy or gait training. Often, symptoms improve or go away with nonsurgical treatment.