Discover the causes behind Tarsal Tunnel Syndrome plus the correct treatment and prevention strategies
The foot is subjected to forces hundreds of times the bodyweight, thousands of times in a day. The ankle is a complex structure that makes weight bearing possible. It allows the foot to flex and extend and absorb the shock of the compressive forces when walking, running and jumping. The ligaments, tendons, nerves and blood vessels travel over and through the ankle joint to the foot.
The posterior tibial nerve runs down from the leg and behind the medial malleolus, the bump on the inside of the ankle, down into the foot. This nerve is protected by a fibrous sheath, called the flexor retinaculum. The flexor retinaculum, along with the bones of the ankle, forms a tunnel for this nerve (and tendons, arteries, veins) that runs through the foot. This tunnel is the tarsal tunnel. The ligament over the tunnel is meant to protect the components underneath, but if it becomes inflamed or a foreign body obstructs the tunnel, then it can become part of the problem.
What is Tarsal Tunnel Syndrome?
Tarsal Tunnel Syndrome, like Carpal Tunnel Syndrome in the wrist, is a compression of the nerve inside the tunnel. It is less common than its counterpart in the wrist and is sometimes simply wrapped into the foot neuropathy diagnosis. The pressure can come from injuries resulting in deformities, inflammation of the protective sheath, tumors, or other impingements on the nerve. The compression on the nerve interferes with the signals sent through the nerve, causing pain and other neuropathy in the foot.
The ankle is formed by the tibia, fibula and talus. The medial malleolus of the tibia and the flexor retinaculum form the walls of the Tarsal Tunnel. The tibial nerve passes through the tunnel into the foot. The tunnel also houses the tendons, veins and arteries that run down into the foot on the medial (inner) side. The bones, ligaments and tendons in the foot innervated by the tibial nerve are also involved in this condition.
Tarsal Tunnel Syndrome image from Clinical Guide to Sports Injuries by Roald Bahr, Sverre Maehlum and Tommy Bolic.
What causes Tarsal Tunnel Syndrome?
Tarsal Tunnel Syndrome has many possible causes and in some cases doctors cannot pinpoint the exact cause. People with flatfeet may develop this condition due to the strain placed on the structures of the feet and a change in the course of the nerves and tendons running into the feet. This could cause pressure on the tibial nerve. A cyst or tumor in the area may also produce pressure on the nerve. Other abnormalities in the area that may cause this condition include varicose veins, a swollen tendon, or a bone spur.
Systemic disease processes, such as rheumatoid arthritis or diabetes, may also cause, or increase the likelihood of, this condition. The inflammation of the joint caused by arthritis will decrease the space available for the nerve, thereby increasing pressure. The veins and arteries passing through may become enlarged due to higher glucose content in diabetics, also causing more pressure on the nerve. Individuals that are overweight or obese may be prone to this condition due to excessive pressure on the posterior tibial nerve.
Injury to the ankle, due to swelling in and around the joint, may also cause pressure on the tibial nerve. Fractures or dislocations may cause the tunnel to shift slightly, or close up. A bone chip in the area of the medial malleolus may also become lodged in the tarsal tunnel, causing an impingement upon the nerve.
Signs and Symptoms
The most common symptom of this condition is pain, burning, or tingling along the inside of the ankle and down into the foot. The pain can vary from prickly points in the foot to severe burning pain along the entire foot and ankle area. The pain generally gets worse with activity, especially prolonged walking or standing and improves with rest. Pain upon palpation of the nerve may also be noted. Loss of sensation may be experienced if the condition is allowed to progress. A change in gait (a limp and overpronation) may also result if not treated promptly.
The symptoms may occur suddenly, but are often made worse by extended periods of activity. The earliest signs of pain are often ignored and the condition is allowed to progress until the nerve is compromised more severely.
Treatment for tarsal tunnel syndrome may include rest, ice (to reduce swelling in the tunnel), NSAIDs (to help with pain and reduce inflammation) and immobilization (this may be necessary to allow the nerve and surrounding tissue to heal.) Physical therapy may be prescribed, as well. An exercise program, ultrasound and other therapies may be used to speed the healing process.
In cases where the pain and inflammation are out of control, injections of a local anesthetic and corticosteroid may be helpful. Bracing may be used in severe cases to reduce the pressure on the foot and on the nerve. Surgical intervention may be required in the most severe cases, or in those cases that do not respond to the non-surgical interventions. This generally involves decompressing the nerve by either; releasing the ligament around it, clearing the obstruction or repairing the structures in the tunnel.
Prevention of tarsal tunnel syndrome starts with the knowledge of what causes it and avoiding those circumstances.
- Rest for the foot in between long bouts of standing or walking is important. Trying to sit down, or at least change position, during extended periods of standing or walking will help reduce the stress on the tarsal tunnel and tibial nerve.
- A proper warm up activity before beginning strenuous workouts will also help prevent injuries to the structures in and around the nerve, reducing the likelihood of compression.
- Wearing properly fitted shoes and orthotics if necessary, will reduce the strain placed on the area. Shoes that are tied incorrectly, or too tightly, can cause damage to this area, also.
- Using wraps or bracing while engaging in athletic pursuits, especially on uneven surfaces or involving sudden direction changes in traffic, may reduce the chances of an ankle injury, which could cause tarsal tunnel syndrome.
- A good strengthening program will keep the supporting muscles of the lower leg strong and reduce leg and ankle injuries. These muscles will also reduce the stress and impact on the joint with each step or landing.
- Flexibility in the muscles of the lower leg will help keep the foot in proper alignment and reduce the pull on the tendons during rest. Flexible muscles are also less likely to be injured.
Stretching is one of the most under-utilized techniques for improving athletic performance and getting rid of those annoying sports injuries. Don't make the mistake of thinking that something as simple as stretching won't be effective.
Article Posted on the Stretching Institute by Brad Walker.
Brad is a leading stretching and sports injury consultant with nearly 20 years experience in the health and fitness industry. For more free articles on stretching, flexibility and sports injury, subscribe to The Stretching & Sports Injury Newsletter by visiting www.thestretchinghandbook.com.