Foot Drop/Common Peroneal Nerves
Common peroneal nerve dysfunction is damage to the peroneal nerve leading to loss of movement or sensation in the foot and leg.
Dysfunction of a single nerve, such as the common peroneal nerve, is called a mononeuropathy. Mononeuropathy means the nerve damage occurred in one area. However, certain body-wide conditions may also cause single nerve injuries.
Damage to the nerve destroys the myelin sheath that covers the axon (branch of the nerve cell). Or it may destroy the whole nerve cell. There is a loss of feeling, muscle control, muscle tone, and eventual loss of muscle mass because the nerves aren’t stimulating the muscles.
- Trauma or injury to the knee
- Fracture of the fibula (a bone of the lower leg)
- Use of a tight plaster cast (or other long-term constriction) of the lower leg
- Crossing the legs regularly
- Regularly wearing high boots
- Pressure to the knee from positions during deep sleep or coma
- Injury during knee surgery or from being placed in an awkward position during anesthesia
- Who are very thin (for example, from anorexia nervosa)
- Who have conditions such as diabetic neuropathy or polyarteritis nodosa
- Who are exposed to certain toxins that can damage the common peroneal nerve
- Decreased sensation, numbness, or tingling in the top of the foot or the outer part of the upper or lower leg
- Foot that drops (unable to hold the foot up)
- “Slapping” gait (walking pattern in which each step makes a slapping noise)
- Toes drag while walking
- Walking problems
- Weakness of the ankles or feet
Exams and Tests
- Loss of muscle control in the lower legs and feet
- Atrophy of the foot or foreleg muscles
- Difficulty lifting up the foot and toes and making toe-out movements
Tests of nerve activity include
- Electromyography (EMG, a test of electrical activity in muscles)
- Nerve conduction tests
- Nerve ultrasound
What other tests are done depend on the suspected cause of nerve dysfunction, and the person’s symptoms and how they developed. Tests may include blood tests, x-rays and scans.
Corticosteroids injected into the area may reduce swelling and pressure on the nerve in some cases.
- The disorder does not go away
- You have problems with movement
- There is evidence that the nerve axon is damaged
The outcome depends on the cause of the problem. Successfully treating the cause may relieve the dysfunction, although it may take several months for the nerve to grow back.
- Decreased ability to walk
- Permanent decrease in sensation in the legs or feet
- Permanent weakness or paralysis in the legs or feet
- Side effects of medication