Tarsal Tunnel Syndrome

Tarsal tunnel syndrome (TTS) is a disorder that arises due to compression of the posterior tibial nerve within the tarsal tunnel, a tight space located on the inner flank of the ankle. The posterior tibial nerve is a major nerve responsible for sensation and motor control in the foot. Compression, irritation, or pinching of this nerve can lead to symptoms such as numbness, pain and tingling in the foot.

Symptoms

The primary symptoms of tarsal tunnel syndrome include:

• Discomfort in the foot, particularly in the arch and heel area.
• Numbness that affects the sole of the foot and toes.
• A tingly sensation in the foot’s sole and toes.
• A burning feeling in the foot.

These symptoms tend to intensify at night and may be alleviated by walking or standing.

Causes

TTS can be caused by several factors, including:

• Flat feet: The tilting of the heel outward and collapsed arches can stretch the nerve along the inner side of the ankle.
• Enlarged masses: Conditions like varicose veins, ganglions, bone spurs, swollen tendons, or soft tissue lumps can take up space in the tunnel, compressing the nerve.
• Injury: An ankle sprain can lead to tissue swelling around the tunnel, putting pressure on the nerve.
• Systemic diseases: Conditions such as diabetes or arthritis can trigger swelling in the tissues, which may lead to nerve compression.

Diagnosis

The doctor can diagnose tarsal tunnel syndrome by reviewing medical history, conducting physical exams, and ordering diagnostic tests. Physical examination involves evaluation of the numbness, pain, and tingling in the foot. The inner flank of the foot and ankle can be tapped to check for symptoms.

Other tests that may be recommended include:

• Nerve conduction studies: Assesses the electrical activity in the nerves of the leg and foot.
• Electromyography (EMG): Measures the electrical activity in the foot’s muscles.
• Ultrasound & MRI: Detect external compression of the posterior tibial nerve caused by a ganglion cyst or bone spur.

Treatment

Several non-surgical treatments are available for TTS based on the underlying cause of the symptoms. They include:

• Nonsteroidal anti-inflammatory drugs (NSAIDs): Medications like ibuprofen can help reduce inflammation if the condition is linked to hindfoot or midfoot arthritis.
• Rest or immobilization: Using a boot to rest the foot can aid in the healing of sprained tissue and allow the compression on the nerve to subside.
• Physiotherapy: Physical therapy can alleviate symptoms related to posterior tibial tendon dysfunction on the inner side of the ankle.
• Steroid or local anesthetic injections: These can help lessen inflammation and may provide a cure in some cases.
• Orthotic insoles, custom shoes or braces: These devices can help support the foot arch and prevent excessive sideways movement of the heel that is common in flat feet and can lead to nerve compression.

Surgery is typically recommended if an isolated abnormal soft tissue mass is found in the tarsal tunnel. In addition, if non-surgical treatments do not relieve symptoms caused by other conditions contributing to tarsal tunnel syndrome, then surgical intervention may be necessary to address the nerve compression.