Tarsal tunnel syndrome
What Is Tarsal Tunnel Syndrome?
Tarsal tunnel syndrome is a compression, or squeezing, on the posterior tibial nerve that produces symptoms anywhere along the path of the nerve running from the inside of the ankle into the foot. Tarsal tunnel syndrome is similar to carpal tunnel syndrome, which occurs in the wrist. Both disorders arise from the compression of a nerve in a confined space.
What Is the Tarsal Tunnel?
The tarsal tunnel is a narrow space that lies on the inside of the ankle next to the ankle bones. The tunnel is covered with a thick ligament (the flexor retinaculum) that protects and maintains the structures contained within the tunnel—arteries, veins, tendons, and nerves. One of these structures is the posterior tibial nerve, which is the focus of tarsal tunnel syndrome.
Causes of Tarsal Tunnel Syndrome
Tarsal tunnel syndrome is caused by anything that produces compression on the posterior tibial nerve, such as:
- A person with flat feet is at risk for developing tarsal tunnel syndrome, because the outward tilting of the heel that occurs with “fallen” arches can produce strain and compression on the nerve.
- An enlarged or abnormal structure that occupies space within the tunnel can compress the nerve. Some examples include a varicose vein, ganglion cyst, swollen tendon, and arthritic bone spur.
- An injury, such as an ankle sprain, may produce inflammation and swelling in or near the tunnel, resulting in compression of the nerve.
- Systemic diseases such as diabetes or arthritis can cause swelling, thus compressing the nerve.
Symptoms
Patients with tarsal tunnel syndrome experience one or more of the following symptoms in the ankle, heel, arch foot or toes:
- Tingling, burning, or a sensation
- Numbness
- Pain, including shooting pain
Symptoms are typically felt on the inside of the ankle and/or on the bottom of the foot. In some people, a symptom may be isolated and occur in just one spot. In others, it may extend to the heel, arch, toes, and even the calf. Sometimes the symptoms of the syndrome appear suddenly. Often they are brought on or aggravated by overuse of the foot, such as in prolonged standing, walking, exercising, or beginning a new exercise program. It is very important to seek early treatment if any of the symptoms of tarsal tunnel syndrome occur. If tarsal tunnel syndrome is left untreated, the condition progresses and may result in permanent nerve damage. In addition, because the symptoms of tarsal tunnel syndrome can be confused with other conditions, proper evaluation is essential so similar to an electrical shock that a correct diagnosis can be made and appropriate treatment initiated.
Diagnosis
Often times a diagnosis of tarsal tunnel syndrome is made after a clinical examination of the foot and ankle. Tapping on the nerve can reproduce the symptoms in many cases. Palpation to feel for a mass in the tunnel is also helpful. Advanced imaging studies, such as an MRI, may be ordered if a mass is suspected or if initial treatment does not reduce the symptoms. Studies used to evaluate nerve problems—electromyography and nerve conduction velocity (EMG/NCV)—may be ordered if the condition shows no improvement with non-surgical treatment.
Non-surgical Treatment
A variety of treatment options, often used in combination, are available to treat tarsal tunnel syndrome. These include: range of motion, stretches, a heel lift, arch supports, orthotics, stable shoes, an ankle brace or cast boot, anti-inflammatory medication, prescription medication to stabilize the nerve, and cortisone injections.
When is Surgery Needed?
In some cases surgery is the best option for treating tarsal tunnel syndrome. When the symptoms do not improve after 6-12 weeks or if muscle weakness or severe pain are present, then surgery is important in order to stop permanent damage to the nerve.
What Type of Surgery is Used?
Surgical release of the ligament overlying the nerve is the primary goal of surgery. However, other factors are also considered – bone spurs, cysts, varicose veins and enlarged tendons.
This information is not intended to diagnose, treat, or prevent any injury or disease. It is intended to serve as an overview of running-related injuries and should not be used as a substitute for sound medical advice from a doctor or therapist.
