What is Superficial Peroneal Nerve Entrapment

Superficial peroneal nerve entrapment is a condition that results from pressure on a nerve in the lower leg (superficial peroneal nerve). This nerve provides feeling to the outside half of the front of your lower leg and the top of your foot and toes.

It also supplies the outer muscles of your lower leg that help your foot move outward. The superficial peroneal nerve begins below the outside of your knee and runs down along your lower leg bone (fibula) to the top of your foot.

Superficial peroneal nerve entrapment can cause weakness and numbness in your leg and foot. It may also cause pain. This can happen anywhere from your lower leg to your ankle.

What are the causes?

This condition may be caused by:

• A hard, direct hit to the outside of your lower leg.
• Ankle sprains.
• A break (fracture) in the fibula.

What increases the risk?

This condition is more likely to develop in people who take part in certain sports or activities, such as:

• Ballet dancing.
• Contact sports, such as football, lacrosse, or martial arts.
• Sports that involve changing direction quickly, such as soccer.
• Sports that take place on uneven surfaces, such as trail running.
• Sports that involve wearing high boots, such as skiing.

What are the signs or symptoms?

Symptoms of this condition include:

• Numbness and tingling over the outside half of your shin and the top of your foot and toes.
• Pain or tenderness on the outside of your leg or top of your foot.
• Inability to move your foot outward or weakness when doing so.

Symptoms of this condition may start quickly or may develop over time. They often get better with rest and get worse after activity.

How is this diagnosed?

This condition may be diagnosed based on:

• Your symptoms and medical history.
• A physical exam. During the exam, your health care provider may:
  • Check for numbness and test the strength of your lower leg muscles.
  • Tap the side of your leg or ankle to see if it causes a tingling sensation.
  • Inject a numbing medicine into the nerve to see if your symptoms go away.
• Imaging tests, such as:
  • X-rays to check your ankle and fibula for fractures.
  • MRI to check tendons and ligaments.
  • Ultrasound to check the nerve.
  • An electrical study of the nerve’s function (electromyography, or EMG).

How is this treated?

Treatment for this condition may include:

• Avoiding activities that make symptoms worse.
• Taking anti-inflammatory pain medicines to relieve swelling and reduce pain.
• Having medicines injected near your nerve to reduce pain and swelling.
• Starting range-of-motion exercises and strengthening exercises.
• Returning gradually to full activity.
• Wearing a supportive shoe or a shoe insert (orthotic).
• Surgery to take pressure off of the nerve. This may be needed if there is no improvement in 2–3 months or if there is a growth on the nerve.

Follow these instructions at home:

Activity

• Return to your normal activities as told by your health care provider. Ask your health care provider what activities are safe for you.
• Do not do any activities that make pain or swelling worse.
• Do not put full weight on your ankle until your health care provider says that you can.
• Do exercises as told by your health care provider.

General instructions

• Wear your supportive shoe or your shoe insert as told by your health care provider.
• Take over-the-counter and prescription medicines only as told by your health care provider.
• Keep all follow-up visits as told by your health care provider. This is important.

How is this prevented?

• Wear supportive footwear that is appropriate for your athletic activity.
• Make sure your shoes or boots fit well and are not too tight.
• See your health care provider if you have an ankle sprain that causes pain and swelling for more than 2 weeks.
• If you start a new athletic activity, start gradually to build up your strength and flexibility.

Contact a health care provider if:

• Your symptoms do not improve in 2–3 months.
• You have increasing weakness or numbness in your leg or foot.

Superficial Peroneal Nerve Entrapment Rehabilitation

Ask your health care provider which exercises are safe for you. Do exercises exactly as told by your health care provider and adjust them as directed. It is normal to feel mild stretching, pulling, tightness, or discomfort as you do these exercises, but you should stop right away if you feel sudden pain or your pain gets worse. Do not begin these exercises until told by your health care provider.

Stretching and range of motion exercises

These exercises warm up your muscles and joints and improve the movement and flexibility of your ankle. These exercises also help to relieve pain, numbness, and tingling.

Exercise A: Ankle inversion, passive

1. Sit with your left / right ankle crossed over your opposite knee.
2. Hold your left / right foot with your opposite hand.
3. Gently pull your foot toward you. Keep your lower leg steady. Your big toe will move toward you and toward the ceiling. You should feel a gentle stretch on the outside of your ankle.
4. Hold the stretch for __________ seconds.

Repeat __________ times. Complete this exercise __________ times a day.

Exercise B: Nerve root

1. Sit on a firm surface that is high enough that you can swing your left / right foot freely.
2. Place a folded towel under your left / right thigh (optional).
3. Drop your head forward and round your back.
4. While you keep your left / right foot relaxed, slowly straighten your left / right knee until you feel a slight pull behind your knee or calf. If your leg is fully extended and you still do not feel a pull, slowly tilt your foot and toes toward you.
5. Hold this position for __________ seconds.
6. Slowly return your knee to its starting position.

Repeat __________ times. Complete this exercise __________ times a day.

Exercise C: Fibular nerve floss

1. Sit with your legs straight in front of you.
2. Slowly move your left / right foot down and inward so your toes point toward the floor and toward your other foot.
3. Hold this position for __________ seconds.
4. Slowly return your foot to the starting position.

Repeat __________ times or for __________ seconds. Complete this exercise __________ times a day.

Strengthening exercises

These exercises build strength and endurance in your foot and ankle. Endurance is the ability to use your muscles for a long time, even after they get tired.

Exercise D: Dorsiflexion

1. Secure a rubber exercise band or tube to an object, such as a table leg, that will stay still if it is pulled on.
2. Secure the other end of the band around your left / right leg.
3. Sit on the floor facing the object, with your left / right leg extended. The band or tube should be slightly tense when your foot is relaxed.
4. Slowly flex your left / right ankle and toes to bring your foot toward you.
5. Hold this position for __________ seconds.
6. Slowly return your foot to the starting position.

Repeat __________ times. Complete this exercise __________ times a day.

Exercise E: Plantar flexion, standing

1. Stand with your feet shoulder-width apart.
2. Keep your weight spread evenly over the width of your feet while you rise up on your toes. Use a wall or table to steady yourself, but try not to use it for support.
3. If this exercise is too easy, shift your weight to your left / right leg until you feel challenged.
4. Hold this position for __________ seconds.

Repeat __________ times. Complete this exercise __________ times a day.