Introduction

Tarsal Tunnel Syndrome (TTS) is a condition that occurs when the posterior tibial nerve located in the ankle is damaged or compressed. It is also known as “tibial nerve dysfunction" or "posterior tibial nerve neuralgia".¹ Common symptoms typically include a sharp pain/ numbness on the sole or arch of the foot. Other symptoms include a tingling burning sensation around the ankle as a result of inflammation.² It is not known to be a common condition due to underdiagnosis and etiology being diverse. For instance, in 20% of cases reported, it is found to be idiopathic instead.³ 

These factors can impact an individual's lifestyle especially those who experience constant pain. It can hinder a person from walking, standing or even standing. It is also known to become worse during the night because of the lack of movement or fluid accumulation. This can result in sleep deprivation which is an issue as the condition does improve with rest. 

Pathophysiology 

The posterior tibial nerve passes through this tunnel alongside other structures, including blood vessels and tendons. It provides sensory and motor functions to the foot, including the sensation of the sole and motor control to muscles that help with foot movement. 

The nerve compression is located throughout different points within a confined space of the tarsal tunnel which can result in the damage or irritation of nerve fibres. It is located on the medial side of the ankle close to the flexor retinaculum, the talus and calcaneus bones. 

• Flexor retinaculum: A transverse carpal ligament which is a strong, fibrous band that acts as a roof for the carpal tunnel⁴
• Talus and calcaneus bones: Bones that are located in the ankle and foot
• Medial malleolus: A supporting bone located on the inner side of the leg and ankle

Symptoms 

Due to the tibial nerve becoming compressed, the ability to transmit electrical signals decline, which results in the impairment of the brain, thus hindering its ability to respond to signals. Therefore, sensory and motor dysfunctions occur in areas of the foot resulting in symptoms such as:

• Pain 
• Tingling or Numbness
• Weakness²

Causes of TTS

Several factors can contribute and cause the compression to occur. Examples include:

• Trauma: Injuries to the foot or ankle are one of the most common causes of TTS. Typically, it is a direct damage or swelling in the tissues around the tarsal tunnel. Injuries include sprains or fractures which lead to inflammation
• Anatomical abnormalities: Anatomical abnormalities are typically structural deformities which can lead to an individual to develop TTS if the condition is located near or around the ankle or foot. Abnormalities can include high arches (Pes Cavus), flat feet (Pes Planus), bony abnormalities such as osteophytes and enlarged tendons
• Systemic conditions: Diagnosis of other conditions can increase the likelihood of an individual to develop systemic inflammation particularly those with diabetes, arthritis, pregnancy and more which can lead to TTS
• Repetitive stress injuries: Stress exerted on the foot or ankle for a prolonged time constantly can worsen the symptoms and pain. For example, sports such as basketball or jumping as well as inappropriate footwear, can prevent the movement of the foot freely. Occupational stress may involve heavy lifting when at work. Excess strain and pressure on the foot can worsen the condition⁵

Conservative treatment 

Non-surgical approaches are used to alleviate symptoms from TTS and improve the patient’s quality of life. Typically, conservative treatments are the first-line of management in order to minimise the effects of any symptoms present. Non-surgical treatments may include:

• Applying no pressure on the foot by resting and reducing the amount of activity so that the nerve is not affected by stress
• Daily stretching and movements are beneficial for strengthening and improving the flexibility of the ankle. This can reduce the pressure on the tibial nerve
• Temporary relief from the pain can be provided by taking a corticosteroid injection
• Compression braces for the ankle provides support to stabilise the ankle from moving incorrectly. This can also reduce any irritation present
• Applying ice packs can help reduce inflammation, while heat therapy may improve circulation and promote healing

Limitations of conservative treatment

Although non-surgical treatments aid with mild or moderate cases of TTS, this is not always the case during its severe stages.. For instance, if TTS has developed further, symptom relief is only temporary when using corticosteroid injections and NSAIDs. This is due to the injection not targeting the root cause of the nerve compression itself.⁶ Despite that, they prevent nerve damage from worsening over time. For instance, they may experience numbness and muscle atrophy which would require surgical interventions to prevent long-term complications. 

Indications for surgical treatment

If conservative treatments fail to decline symptoms and provide relief, surgical interventions are taken into account. They are beneficial as they help to detect any abnormalities during image screening. For instance, cysts, varicose veins or bone spurs which compress the nerve. In these conditions, nerve decompression may be required.

Limitations for these surgical interventions is the risk of irreversible damage if nerve compression is prolonged. As a result chronic pain can be developed and sensory deficits can arise due to impairment to the brain. This can impact a person's quality of life. However, severe cases of untreated TTS results in muscle weakness, loss of coordination and impaired mobility. Without timely intervention, symptoms may progressively worsen, making recovery more challenging even after surgery.⁷

Surgical procedures for tarsal tunnel syndrome

Tarsal tunnel decompression surgery

The first-line of treatment is decompression to relieve pressure on the tibial nerve. It will relieve pain and reduce symptoms. The procedure for the surgery consists of the steps:

1. Anesthesia
2. Incision – A small incision is made along the inside of the ankle near the tarsal tunnel
3. Nerve Decompression – The surgeon carefully releases the flexor retinaculum and any other tight or abnormal structures pressing on the tibial nerve
4. Closure – The incision is sutured, and the foot is bandaged for protection during recovery⁸

Patients have presented a significant relief from pain and improvement in mobility. Many individuals achieve long-term symptom relief. Full recovery may take several months, with physical therapy playing a key role in rehabilitation.

Other surgical options include nerve transposition. This involves the process of moving the nerve from its original position to a new location so that irritations can be reduced.¹¹ Furthermore, abnormal structures within TTS can be removed by undergoing space-occupying lesions. These lesions can be ganglion cysts which are fluid-filled sacs, bone spurs which are abnormal bony growths.^9,12 

Post-surgery considerations and recovery

Recovery timeline

Recovery from TTS typically takes several weeks to months, depending on the severity of the condition and individual healing rates.¹⁰ Immediate postoperative care can include rest and elevation of the foot. It is important to prevent heavy exertion on the injury to allow the ankle to heal. Physical therapy also helps to restore mobility and prevent stiffness. Patients should have regular check-ups to monitor healing progression to address any complications. 

Long-term prognosis

During post surgery, patients have shown improvements in symptoms including a reduction in pain and ability to move the ankle. However, long-term outcomes depend on factors such as adherence to rehabilitation, severity of preoperative nerve damage, and the presence of underlying conditions.

Possible complications

Although it is a safe surgical procedure, it is important to follow wound care and hygiene regulations to reduce the risk of infections. However, mobility can be limited due to scar tissue forming. 

FAQs

What is tarsal tunnel syndrome (TTS)? 

A condition caused by the damage or compression of the posterior tibial nerve that runs through the tarsal tunnel in the ankle. 

What are the common symptoms?

Common symptoms include a sharp pain or numbness in the sole of the foot. Inflammation can be caused by a burning sensation and tingling as well as caused by other underlying conditions such as diabetes. Furthermore, symptoms worsen during night due to lack of movement and weakness can be developed. 

What are the causes?

• Trauma 
• Anatomical abnormalities 
• Systemic conditions 
• Repetitive stress to injuries 

How is TTS diagnosed and treated?

Typically it is diagnosed by physical examination and first-line of treatment includes resting, physical therapy (gentle exercises) and corticosteroid injections. 

Summary

TTS is a condition that is caused by the compression of the tibial nerve which can result in sensory dysfunctions and symptoms that can impact the quality of life. Conservative treatments help to manage and reduce symptoms. However, when non-surgical approaches fail, surgical decompression can provide lasting relief. Early diagnosis and intervention are critical in preventing long-term complications.