Overview

Tarsal tunnel syndrome (TTS) is a syndrome that occurs when the posterior tibial nerves or one of its associated branches are compressed either individually or collectively. Entrapment or damage to the tibial nerve can cause this condition. The tarsal tunnel is a passage in the inner ankle where the tibial nerve, tendons, veins and arteries pass through.

Obesity is a term used to describe a person with an excess of body fat. An obese patient is a person with a Body Mass Index (BMI) of 30 or more. An ideal BMI is between 18.5 to 24.9, whilst a BMI of 25 to 29.9 is categorised as overweight. Obesity is a serious health condition that can cause many morbidities in the human body, including tarsal tunnel syndrome.

Understanding tarsal tunnel syndrome

Tarsal tunnel syndrome is a condition that occurs when the tibial nerve is damaged or compressed as it passes through the tarsal tunnel.

Patients suffering from tarsal tunnel syndrome complain of symptoms that affect the plantar aspect of the foot. Common symptoms include sensory disturbances to the foot, such as localised or radiating pain, burning pain, paraesthesia, tingling sensation in the toes or sole of the foot, numbness of the foot, nocturnal awakening with the foot tingling, and cramping of the foot.¹ Taking rest and elevating the leg often relieves symptoms.²

The onset of the pain in tarsal tunnel syndrome is insidious. The numbness felt correlates with the tibial nerve that is being compressed or has been damaged. 

The pain radiates distally to the entrapment and may involve the toe. However, the pain can radiate proximally and may involve the calf. The pain worsens after prolonged standing,g whilst at night, some relief can be found with rest and elevation of the foot. There may be decreased sensation to touch and pinprick, and some weakness when flexing the foot.³

Any condition that can compress or damage the tarsal tunnel can result to tarsal tunnel syndrome.² Some of the causes of tarsal tunnel syndrome include:

• Trauma to the ankle
• Generalised lower extremity oedema
• Masses of soft tissues such as lipoma, neurilemoma, venous congestion, varicosities
• Tendon pathology
• Diabetes
• Obesity
• Post-surgical scarring
• Valgus or varus foot
• Systemic diseases such as inflammatory arthropathies or tendinopathies

The role of obesity in foot biomechanics

Biomechanics simply refers to the internal and external forces acting on the human body and the effects produced by these forces. Obesity is a worldwide health problem, and it affects different systems in the body, including the musculoskeletal system. Amongst musculoskeletal problems, foot issues are the most pressing, and this may be due to the increased stress placed on the foot as a result of the need to bear excess weight. The human foot gives the body support and propels the body around from one place to the other. Obesity causes an increase in the forefoot width to foot length ratio. Obese men and women have constant pressure under the midfoot, heel and forefoot while standing. Peak pressures during walking are also increased under most foot areas.⁴ An increase in fat tissue in an obese patient externally compresses the tarsal tunnel, which can damage or compress the tibial nerve, thus causing pain. Additionally, obesity may also change the style a person walks, which causes damage to the foot and ankles.⁵

How obesity contributes to nerve compression

Being obese causes fat tissue to compress on the tibial nerve, leading to tarsal syndrome. A pressure greater than 20 mm Hg is enough to reduce blood flow within the veins, and pressure greater than 40 mm Hg is sufficient to reduce blood flow within the arteries of the nerve.¹ Whereas a pressure more than 80 mm Hg causes structural changes which irreversibly damage the nerve.¹ Reduced blood flow to a nerve will make the nerve to have ischaemia, which can result to symptoms observed in tarsal tunnel syndrome, such as numbness, tingling sensation and pain.

Prevention and management strategies

The only method of preventing obesity-induced tarsal tunnel syndrome is by exercising regularly and keeping your BMI between 18.5 to 24.9.

There are several ways of managing tarsal tunnel syndrome and tackling the leading cause of syndrome can help in resolving the condition. In the case of tarsal tunnel syndrome caused by obesity, we can manage it by doing the following:

1. Diet and exercise: Being strategic and working on your weight is very important. You can get a gym trainer to guide you on how to lose weight, and you can do different kinds of exercise like skipping rope, running, jogging and others. Being intentional and determined is the most important thing when going through the journey of weight loss. Also, minding what you eat is another important thing. You will have to avoid junk meals and focus on natural meals like fruits, vegetables and home-cooked meals. Being cautious with your diet and weight loss will reduce the pressure on the tarsal tunnel and thus reduce the compression on the tibial nerve
2. Pain-relieving medications: It is ideal that if you are having pain due to tarsal tunnel syndrome or any other medical condition causing pain, you should see your doctor so that they may prescribe painkillers for you. Self-medication is discouraged, a medical doctor knows the best pain reliever for your condition. Anti-inflammatory drugs, analgesic acetaminophen, steroid injections or neuropathic drugs may be prescribed to you after considering your medical history⁶
3. Physical therapy and stretching: These can help improve your strength and range of motion
4. Wearing braces: Braces keep your foot in place to promote healing. Your doctor could prescribe braces to reduce the pressure on your foot
5. Orthotics: Wearing custom-made shoe inserts known as orthotics has proven to be helpful. Custom-made shoe inserts can be beneficial in supporting the natural arch of your foot. By maintaining this alignment, they help minimise movements that could lead to nerve compression. Additionally, wearing stability or motion-control shoes helps prevent excessive inward rolling (pronation) and alleviates pressure on the nerve
6. Surgery: This is usually the last resort when conservative methods of treatment fail. Your health care provider may refer you to a surgeon if your symptoms persist after exhausting conservative therapies²

FAQs

What is tarsal tunnel syndrome (TTS)?

Tarsal tunnel syndrome occurs when the posterior tibial nerve or its branches become compressed as they pass through the tarsal tunnel in the inner ankle. This compression can lead to pain, tingling, numbness, and burning sensations in the foot.

How does obesity contribute to tarsal tunnel syndrome?

Obesity increases fat tissue around the foot and ankle, which can put pressure on the tibial nerve. This compression reduces blood flow and can lead to nerve damage, causing symptoms like pain and tingling in the foot.

What are the symptoms of tarsal tunnel syndrome?

Symptoms include localised or radiating foot pain, burning sensations, tingling in the toes or sole, numbness, nighttime foot cramps, and worsening pain after prolonged standing.

Can obesity affect foot biomechanics?

Yes, excess body weight increases stress on the foot, alters walking patterns, and changes pressure distribution, leading to foot and ankle problems, including tarsal tunnel syndrome.

How can I prevent tarsal tunnel syndrome related to obesity?

Maintaining a healthy body weight through regular exercise and a balanced diet can help prevent excess pressure on the tibial nerve. Wearing proper footwear can also support foot alignment.

What are the treatment options for tarsal tunnel syndrome?

Treatment includes weight management, physical therapy, wearing orthotics, taking pain-relieving medications, using braces, and, in severe cases, undergoing surgery.

How does weight loss help in managing tarsal tunnel syndrome?

Losing body weight reduces pressure on the tarsal tunnel and tibial nerve, relieving symptoms and improving foot biomechanics.

When should I see a doctor for tarsal tunnel syndrome?

If you experience persistent foot pain, numbness, or tingling that worsens over time or affects mobility, consult a healthcare provider for proper diagnosis and treatment.

Summary

Tarsal tunnel syndrome is a painful condition caused by the compression of the tibial nerve as it passes through the tarsal tunnel. While multiple factors can contribute to this syndrome, obesity plays a significant role by increasing pressure on the foot, thereby altering biomechanics and directly compressing the nerve. Managing body weight through a healthy diet, regular exercise, and lifestyle modifications can help prevent and alleviate symptoms. Treatment options range from conservative approaches like orthotics, physical therapy, and pain-relief medications to surgical intervention in severe cases. Seeking medical advice early and adopting preventive strategies can significantly improve foot health and overall well-being.