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The Nerve of Knee Disclocations

The knee is a sturdy joint, but it can dislocate as a result of injury. When this happens, there's a risk of injury to the nerves around the knee. Two nerves that may be injured are the peroneal and tibial nerves. The peroneal nerve has two main parts: one is close to the skin and the other deep in the muscles. Together, they are all called peripheral nerves.

Each nerve has two jobs. It receives and sends information about sensation. This is the sensory component of the nerve. It also controls the movement of the leg by giving the muscle messages to contract. This is the motor component.

The force of a knee dislocation may be enough to stretch or disrupt nearby nerves. This can result in pain, numbness, loss of motion, and a condition called foot drop. Nerve damage to the muscles that hold or pull the foot up is a cause of foot drop.

If a nerve isn't completely destroyed, it can grow back. Nerves regrow at a rate of one millimeter each day or three centimeters each month (about one-half of an inch). If severe nerve injury has taken place, then surgery may be needed.

Surgery can repair the nerve or release it from scar tissue. The timing of the operation is important. If the nerve repair is delayed by nine to 12 months, then the chance of success is much lower. After nine months, muscle wasting and scarring may be permanent.

Studies show that incomplete nerve paralysis after knee dislocation can can heal if given enough time. Patients with complete nerve paralysis will likely need surgery. An operation at the right time improves the chances for a good recovery.

References: Robert J. Goitz, MD, and Matthew M. Tomaino, MD. Management of Peroneal Nerve Injuries Associated With Knee Dislocations. In The American Journal of Orthopedics. January 2003. Vol. 32. No. 1. Pp. 14-16.

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