Tarsal Tunnel Syndrome
The Tarsal Tunnel is a region on the inner part of the ankle, just below the ankle bone (the “medial malleolus”). It’s formed by a thick ligament over the top and the bones of the ankle below. The tunnel contains several tendons, blood vessels, and the Posterior Tibial Nerve.
What is Tarsal Tunnel Syndrome?
Similar to Carpal Tunnel Syndrome in the hand/wrist, Tarsal Tunnel Syndrome involves compression of the nerve that runs through the tunnel, in this case, the Posterior Tibial Nerve. The nerve can get squeezed by the tendons that also run through a tunnel alongside the nerve. When the nerve gets pinched or squeezed it irritates the nerve, and that causes the symptoms.
What causes Tarsal Tunnel Syndrome?
Anything that squeezes or puts pressure on the posterior tibial nerve can cause TTS, such as:
- Flat feet or “fallen” arches. Especially if you stand for long periods, such as at work, without good arch support, this can put stress on the Tarsal Tunnel.
- Tendinitis of any of the tendons passing through the tunnel. Tendinitis can cause swelling, enlargement, and inflammation of the tendon(s), and that can put increased pressure on the nerve.
- Chronic ankle instability. A loose ankle can put increased stress on the Tarsal Tunnel and its contents.
- Pregnancy. The increased body weight, combined with ligament looseness due to hormonal changes, and fluid retention during pregnancy, can cause the arches to collapse and the tunnel to swell.
- Medical conditions such as diabetes, thyroid disorders, and other diseases.
Sometimes the symptoms occur suddenly, especially, for example, when beginning a new exercise program. More often they develop over time from repetitive use.
What are the symptoms of Tarsal Tunnel Syndrome?
The most common symptoms include:
- Tingling, burning or pain along the arch and/or bottom of the foot
- Numbness along the bottom of the foot
- Pain along the bottom of the foot.
Symptoms are typically felt on the inside of the ankle and/or on the bottom of the foot. Sometimes, symptoms may be isolated to just one spot. Other times, symptoms may radiate to the heel, arch, and/or toes. Rarely you may even feel symptoms in the calf.
How is Tarsal Tunnel Syndrome diagnosed?
The first step in diagnosis is a thorough and detailed history of your symptoms and how they started, combined with a proper physical exam. X-rays may help to identify underlying problems with the joints, such as arthritis. Diagnostic musculoskeletal ultrasound can identify a swollen and enlarged nerve. MRI is rarely needed but can be helpful to identify other potential problems. Sometimes nerve testing, such as an EMG/NCV test (“electromyography” and “nerve conduction velocity”) can be done, but this is rarely necessary for the initial phases of diagnosis and treatment.
How is Tarsal Tunnel Syndrome treated?
Non-surgical treatment is always the first step. Surgery very rarely is needed. Initial treatment would include:
- Physical therapy
- Splinting or bracing
- Arch supports or orthotics
- Wearing shoes with better cushion and arch support
- Cortisone injection
- Modifying the offending activities, when possible
If there is an underlying tendon problem that might contribute to the TTS, such as tendinitis or a partial tear, then that should also be addressed.
When these conventional measures fail, the physicians at the New England Stem Cell Institute may perform “nerve hydrodissection” treatment. This is a painless procedure where a mixture of sterile saline and a small amount of anesthetic is injected around the nerve within the Tarsal Tunnel under ultrasound guidance to help reduce the pinching of the nerve.