The peroneal nerve is a branch of the sciatic nerve which runs down the outside of the lower leg, serving the peroneal muscles which help pull the foot upwards and inwards. Symptoms include numbness & tingling in the lower leg and are often caused by a blow to the outside of the knee.
Peroneal nerve injury symptoms
Symptoms of a peroneal nerve injury, also known as peroneal neuropathy include numbness or tingling in the front and or side of the lower leg. There will be decreased sensitivity when touching these areas. Weakness in lifting the foot upwards and turning it outwards may be experienced and in severe cases - foot drop will occur where the foot cannot be lifted up enough to clear the floor when walking. A slapping gait may be seen as the foot slaps on the ground when walking.
Causes of peroneal nerve injury
This nerve may be injured in a number of ways including injury to the outside of the knee where the nerve is very close to the skin. Swelling, inflammation or infection can also injure the peroneal nerve as can repeated pressure on the outside of the knee from for example sitting with legs crossed in tight clothing.
Similar symptoms may be present due to compression of the nerve at a higher level, usually either at the nerve root in the lumbar spine (L4 - S3) or in the buttocks.
Treatment of peroneal nerve injuries
Treatment depends on the cause of the injury. Peroneal nerve symptoms caused by an acute injury to the outer knee may resolve once the knee injury has healed and any swelling or pressure on the nerve has dispersed. If an injury is caused by repetitive compression then this should be addressed.
Symptoms caused by damage to the nerve itself (i.e. from a fracture or dislocation) are more difficult to treat, although, in all but the most severe cases, the damage will usually heal itself, although this can be a very slow process. In the meantime, physical therapy may be beneficial in improving muscle strength and control. Exercises to stretch and strengthen the muscle of the lower leg may help improve the condition.