Peroneal Nerve Injury

The common peroneal nerve branches from the sciatic nerve and provides sensation to the front and sides of the legs and to the top of the feet. This nerve also controls the muscles in the leg that lift the ankle and toes upward. Injuries to the peroneal nerve can cause numbness, tingling, pain, weakness and a gait problem called foot drop.

What You Need to Know

The branches of the common peroneal nerve innervate and control the muscles in the legs that lift the ankle and toes upward (dorsi flexion).

Mild peroneal nerve injuries can cause numbness, tingling, pain and weakness.
More severe injuries can be characterized by a foot drop, a distinctive way of walking that results from being unable to bend or flex the foot upward at the ankle.
Other neurological conditions, for example a herniated disc, can also cause foot drop.

What causes peroneal nerve injury?

The peroneal nerve can be injured by trauma and nerve compression, including:

Knee dislocation
Knee or leg fracture
Knee or hip replacement surgery
Compression of the peroneal nerve in the leg
Compression of the peroneal nerve by a nerve sheath tumor or nerve cyst

Because other underlying medical conditions can cause the same symptoms as peroneal nerve injury, it is important to be evaluated by an expert who can diagnose your condition and offer appropriate treatment options.

Some neurologic conditions can cause symptoms similar to peroneal nerve injuries, including:

Amyotrophic lateral sclerosis (also known as ALS or Lou Gehrig’s disease)
Multiple sclerosis
Parkinson’s disease
Herniated lumbar disk

Peroneal Nerve Injury Symptoms

Inability to point the toes upward or lift the ankle up (dorsiflexion)
Pain, weakness or numbness affecting the shin or the top of the foot
Loss of ability to move the foot
A distinctive gait where the knee is raised higher than normal to clear the foot from the ground when the leg swings forward (also called steppage or foot drop gait)

Diagnosis of Peroneal Nerve Injury

A doctor needs to accurately diagnose the underlying cause of a peroneal nerve injury in order to prescribe the most appropriate therapy. When assessing a person who may have a peroneal nerve injury, the doctor will begin with a careful history and proceed with a comprehensive clinical and neurologic exam.

In order to locate and fully determine the extent of the nerve injury, the doctor may order tests to evaluate how the muscles and nerves are functioning, including:

Electromyography, which measures ongoing muscle activity and response to a nerve’s stimulation of the muscle.
Nerve conduction study, which measures the amount and speed of conduction of an electrical impulse through a nerve.

The doctor may also order any of the following imaging techniques:

CT scan
Ultrasound
MRI
- MR neurography: An MRI that uses specific settings or sequences that provide enhanced images of nerves. From the patient’s perspective, the experience is the same as undergoing a regular MRI.

Peroneal Nerve Injury Treatment

Depending on the location and degree of the nerve damage, the doctor may prescribe different courses of therapy. If the problem is caused by an underlying illness, it is important to address that issue.

Nonsurgical treatments, including orthotics, braces or foot splints that fit inside the person’s shoe, can bring relief. Physical therapy and gait retraining can help the person improve their mobility.

Some injuries may require peripheral nerve surgery, including one or more of these procedures: