Peroneal Nerve Injury

A peroneal nerve injury happens when you damage the nerve that manages sensation or feeling in your lower leg and foot. Your peroneal nerve (peroneal fibular nerve) also allows you to lift your toes and ankles. Healthcare providers may refer to this as peroneal nerve palsy or peroneal neuropathy.

Peroneal (pronounced “pair-uh-NEE-uhl”) nerve injuries may cause a tingling sensation in your foot and lower leg, pain or weakness. You may also have a foot drop, a problem that occurs when you can’t lift your foot upward at your ankle.

What is the common peroneal nerve?

The common peroneal nerve (common fibular 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. There, the common nerve splits into two branches:

• Deep peroneal nerve: This branch runs down the inner side of your leg and over your ankle bone. It controls the muscles that pull your foot up at your ankle, and it helps you point your toes. It also supplies feeling to the skin between your big and second toes.
• Superficial peroneal nerve: This branch runs down the outer side of your leg. It’s responsible for feeling in the outer two-thirds of your leg and the top of your foot. It helps control the movement of all of your other toes.

Symptoms of a peroneal neuropathy

Peroneal neuropathy symptoms may include:

• Weakness or inability to move your foot or raise the front of your foot
• Numbness in your shin or the top of your foot
• Pain in your foot or lower leg
• Tingling or pins-and-needles feeling in your foot or lower leg

Common peroneal nerve injury causes

Trauma, compression, chronic conditions or surgery can affect this nerve. Examples include:

• Trauma: Breaking your ankle, knee or fibula can affect your common peroneal nerve. Your fibula is the long bone on the outer side of your leg.
• Compression: This is pressure on the nerve. It can happen if you have a blood clot, severe swelling or a tumor that presses on it. You can also damage this nerve if you need to wear a very tight cast on your ankle or leg.
• Chronic conditions: Charcot-Marie-Tooth disease, lupus and Type 2 diabetes are examples of long-term (chronic) conditions that may affect your common fibular nerve.
• Surgery: Knee or hip replacement surgeries may affect it if you develop a blood clot in your lower leg during recovery. The clot may cause severe swelling that can press on your peroneal nerve.
• Low back issues: A herniated disk or other low back issues that put pressure on your spine and nerves can cause foot drop, lower leg pain and numbness.

How doctors diagnose this injury

A healthcare provider will ask about your symptoms and check your legs and feet. They may do the following tests:

• Imaging tests: They may do a CT scan, MRI, ultrasound or a magnetic resonance (MR) neurography. This is a special MRI that gives providers pictures of your nerves.
• Electromyogram: This test checks how your muscles react to nerve stimulation.
• Nerve conduction study: This measures how electrical impulses run through your nerves.

How is a common fibular nerve injury treated?

Your treatment will vary depending on the injury type and severity. Your healthcare provider will likely start with nonsurgical treatments like:

• Functional electric stimulation: This treatment sends an electric impulse to your deep peroneal nerve. The impulse triggers the muscles that help you lift your foot while you walk.
• Orthotics: These are devices, like shoe inserts or braces, which support your foot and help with pain. An ankle foot orthosis (AFO) is a brace that you wear around your foot and ankle. It fits inside your shoe to prevent foot drop or catching your toes on the ground when you walk.
• Physical therapy: You may have gait training, which is special physical therapy that improves your ability to stand and walk.

Your provider may recommend surgery if nonsurgical treatments aren’t effective. An orthopaedic surgeon may do procedures that:

• Relieve pressure on the nerve
• Repair the nerve
• Replace the damaged nerve with donor tissue

Recovery time

Recovery from surgery can take up to three to four months. Your orthopaedic surgeon will explain what you can expect. They may note activities you should avoid. Generally, you’ll limit activities for the first six weeks after surgery. After six weeks, you should be able to be more active.

When should I seek care?

You should talk to a healthcare provider if you can’t lift the front of your foot or move your foot. Numbness or unexplained pain in your lower leg are also reasons to seek care. You may want to ask your provider questions like:

• What may have damaged my peroneal nerve?
• What happens if I don’t get treatment?
• Will I need surgery?

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

Nonsurgical treatment may eliminate or reduce your symptoms. But nerves heal very slowly. It may take time before you notice an improvement. In some severe cases, the injury and your symptoms may not go away. Your situation may be different if you need surgery. In that case, your surgeon can explain what you can expect.