Tarsal Tunnel Syndrome (TTS) is a condition affecting the foot and ankle, causing discomfort due to nerve compression. It occurs when the posterior tibial nerve, which runs through a narrow passage in the inner ankle, becomes compressed or irritated. Whether TTS goes away depends heavily on the underlying cause and how quickly treatment is initiated. Many cases resolve completely with non-surgical intervention, but persistent symptoms may require surgery.
What Tarsal Tunnel Syndrome Is
Tarsal Tunnel Syndrome is defined as a compressive neuropathy of the posterior tibial nerve within the tarsal tunnel. This tunnel is a tight space located on the inside of the ankle, positioned behind the bony prominence known as the medial malleolus. The tunnel is formed by ankle bones (the calcaneus and talus) and is covered by a thick band of tissue called the flexor retinaculum.
The posterior tibial nerve travels through this confined space alongside blood vessels and tendons. Here, it divides into three main branches that supply sensation to the sole of the foot. When the nerve is squeezed or stretched, it produces characteristic signs of nerve pain. Common symptoms include a sharp, burning sensation, numbness, and tingling, often described as “pins and needles,” primarily on the bottom of the foot or the toes.
Compression arises from factors that reduce the space within the tunnel or stretch the nerve. Mechanical issues like flat feet (pes planus) can cause increased traction and compression. Other causes include trauma, such as swelling from an ankle sprain or fracture, and space-occupying lesions. These lesions can be benign tumors, ganglion cysts, bone spurs, or varicose veins that press against the nerve.
Conservative Treatments Aimed at Resolution
The initial management strategy focuses on non-surgical methods to relieve pressure and inflammation on the posterior tibial nerve. The goal of conservative treatments is to resolve the condition by addressing the mechanical or inflammatory factors causing the compression. Resting the foot and ankle, often combined with immobilization using a brace or splint, helps limit movement that can aggravate the compressed nerve.
Nonsteroidal anti-inflammatory drugs (NSAIDs) are used to manage pain and reduce local swelling contributing to nerve irritation. Custom orthotics are an important intervention, especially for patients with underlying biomechanical issues like flat feet. These custom inserts stabilize the foot and correct irregular walking patterns, reducing strain and compression on the tibial nerve.
Physical therapy plays a significant role in recovery, including strengthening exercises for foot muscles and stretches for the calf muscles. Specific nerve gliding exercises are also taught to promote normal movement and prevent friction around the nerve. If symptoms persist, a corticosteroid injection may be administered directly into the tarsal tunnel. This anti-inflammatory medication can significantly reduce swelling, which may lead to complete and lasting relief of symptoms.
Addressing Persistent or Recurring Symptoms
When conservative treatments fail to provide lasting relief after three to six months, or if a specific space-occupying lesion is identified, surgery may be necessary. Surgery, known as Tarsal Tunnel Release or decompression, is reserved for cases with persistent or worsening symptoms, or evidence of advanced nerve damage like muscle weakness. The procedure aims to physically free the posterior tibial nerve and its branches from the surrounding restrictive tissues.
During the surgery, the surgeon makes an incision on the inner ankle and cuts the flexor retinaculum, which forms the roof of the tunnel. This action permanently increases the space within the tunnel, immediately reducing pressure on the nerve. The surgeon also ensures that all three nerve branches are fully decompressed, including the release of the deep fascia of the abductor hallucis muscle distally. The success rate is high, with many patients experiencing a significant reduction or elimination of burning, tingling, and numbness.
Prognosis is best when symptoms have been present for less than one year, or when a clear cause like a ganglion cyst was removed. Recovery involves light walking within a few weeks, with a full return to normal activity often taking several months. Recurrence after surgery, while uncommon, can happen due to inadequate initial release, the formation of scar tissue around the nerve, or a persistent underlying condition.