Tarsal tunnel syndrome is a neuropathic disease due to damage or inflammation of the posterior tibial nerve due to the compression of the structures within the tarsal tunnel. The tunnel is a narrow fibro-osseous space that runs posterior and anterior to the medial malleolus. Its components from the medial to the lateral foot are
- Tibialis posterior tendon,
- Flexor Digitorum Longus (FDL) tendon posterior tibial artery
- Posterior tibial vein
- posterior tibial nerve, and
- Flexor Hallucis Longus (FHL) tendon.
The tibial nerve divides into two branches, namely the medial and lateral plantar nerves, as it exits the tarsal tunnel. These branches supply muscles and digits on their respective sides of the foot. Tarsal tunnel syndrome, if left untreated, can cause permanent nerve damage and disability or deformity in the foot or ankle.
Now, let’s discuss the symptoms of tarsal tunnel syndrome, which are discussed in detail below.
Symptoms of Tarsal Tunnel Syndrome
Generally, tarsal tunnel syndrome symptoms ensue in the medial ankle or plantar foot, making it difficult for the patients to identify them. Below are the symptoms of this syndrome.
Pain in the Foot or Ankle: Patients commonly complain of pain directly over the tarsal tunnel that radiates into the arches and plantar foot. They may experience sharp shooting pain along the branches of the posterior tibial nerve.
Numbness or Tingling: Most patients experience numbness and tingling sensation across the plantar surface of the foot and toes.
Burning Sensation in the Foot: The patient experiences a burning sensation along the region innervated by the tibial nerve.
Weakness in the Foot: In chronic cases, compression affects tendons and ligaments in the tarsal tunnel, weakening the associated foot muscles. It also causes contractures in the toes.
Swelling in the Foot or Ankle: The fluid accumulation in response to inflammation causes swelling in the ankle or foot.
Difficulty Standing or Walking: Besides pain, numbness, and tingling sensation, patients experience difficulty standing and walking.
Now, let’s discuss the causes of tarsal tunnel syndrome, which are discussed in detail below.
Causes of Tarsal Tunnel Syndrome
Tarsal tunnel syndrome is caused due to many factors, some of which are common. They are discussed below:
- Compression of the Tibial Nerve
Compression of the tibial nerve causes inflammation, increasing sensitivity. When moved, it can cause pain and tingling sensation in the foot and ankle.
- Injuries or Trauma to the Foot or Ankle
Ankle sprain or fracture can lead to fibrosis of the periarticular region and wears ligaments. These changes result in the compression of structures within the tarsal tunnel causing the neuralgia of the posterior tibial nerve.
- Overuse or Repetitive Stress
The tarsal tunnel shrinks repetitively upon exerting sustained force. It doesn’t help restore its original form, further aggravating the pathological changes in the tibial nerve.
- Medical Conditions
Systemic conditions such as hyperthyroidism, diabetes mellitus, arthritis, sclerosis, and chronic renal failure, increase the risk of tarsal tunnel syndrome development. The abnormalities associated with the condition promote pathological changes that exacerbate the harmful effects on the tibial nerve and biomechanical aspects of the tarsal tunnel.
Diagnosis of Tarsal Tunnel Syndrome
- Physical Examination
Examiners palpitate the tarsal tunnel and look for signs of tenderness in muscles and toes. It includes gait abnormalities, such as excessive pronation or supination, toe eversion, excessive foot inversion or eversion, and antalgic gait.
Tinel Test: The test usually involves tapping gently on the tarsal tunnel. Pain or tingling sensation along the nerve distribution is a sign of this syndrome.
Dorsiflexion-Eversion Test: The test involves holding the ankle in dorsiflexed and everted position to the end of the freedom of motion for 10 seconds. Pain or tingling sensation indicates tarsal tunnel syndrome.
Other physical tests include
- Two-point discrimination test.
- Evaluation of the range of motion of the foot and muscle strength.
- Imaging Tests
X-ray scans may help visualize structural deformities such as osteophytes, hindfoot varus, valgus, tarsal coalition, or evidence of previous trauma.
MRI scan does not help identify damage to the tarsal tunnel, but it helps rule out other causes of pain by aiding visual observation of muscles. It can evaluate soft tissue abnormalities, such as tendonitis or tenosynovitis, lipomas or other growths, varicose veins, and ganglion cysts.
- Nerve Conduction Studies
These studies and electromyography help identify abnormal sensory and motor sensory nerves. The limitation of the modality is suboptimal sensitivity and specificity.
Now that we have discussed the ways to recognize or identify the syndrome. Let’s discuss the treatment options for tarsal tunnel syndrome.
Treatment of Tarsal Tunnel Syndrome
Usually, treatment of tarsal tunnel syndrome is challenging due to a lack of accurate and specific diagnostic methods. However, doctors determine the treatment strategy based on the degree of loss of foot function and ankle and causes.
- Rest and Ice
Taking stress on the foot and ankle off prevents inflammation from progressing and promotes the healing process. Placing ice wrapped in a cloth on the ankle reduces the effect of heat on the affected tissues and relieves pain.
- Physical Therapy
Physical therapy helps patients by alleviating symptoms and restoring nerve function. The elements of physical therapy for tarsal tunnel treatment are as follows.
- Ultrasound
- Iontophoresis
- Phonophoresis
- E-stim
- Calf stretching
- Nerve mobility or nerve gliding
- Exercises to strengthen the posterior tibialis
- Use of kinesiology tape to provide support to the arch and reduce biomechanical stress
- Medications for Pain Relief
The following drugs can relieve pain, allowing foot and ankle movement.
- Oral Analgesics: Acetaminophen and non-steroidal anti-inflammatory drugs
- Neuropathic Pain Medications: Tricyclic antidepressants, pregabalin, and gabapentin
- Topical Medications: Lidocaine and NSAIDs
- Steroid Injections
Corticosteroid injections into the tarsal tunnel can help relieve pain and reduce inflammation.
- Surgery
Surgical intervention depends upon the failure of conservative modalities, and the exact cause is known. The procedure involves decompression of the posterior tibial nerve by releasing the flexor retinaculum from the medial malleolus. The release stretches the surrounding tissues allowing more space for the nerve.
The prognosis after surgery is better in
- Patients who responded positively to the Tinel test than those who tested negative
- Younger individuals and patients with a short history of symptoms, early diagnosis, known etiology, and no previous ankle pathology.
Prevention of Tarsal Tunnel Syndrome
- Proper Footwear
Footwear with a medial heel wedge reduces traction on the posterior tibial nerve, corrects biomechanical abnormalities, and decreases the load on the tarsal tunnel. Footwear with better arch support reduces symptoms.
- Stretching and Strengthening Exercises
Stretching exercise increases support to the tendons inside the tarsal tunnel. Rotating ankles in clockwise and anticlockwise directions for an equal duration helps.
Pencil lift, which involves picking a pencil off the ground using toes and holding it in the air for a few seconds, strengthens foot and ankle muscles and provides better support to the tendons.
- Avoiding Overuse or Repetitive Stress
Regulating foot movement helps reduce excessive downward force along the tibia. Excessive walking and carrying heavy objects for a long time increases the pressure on the nerve. Therefore, avoiding such activities reduces the worsening of the condition.
- Managing Medical Conditions
Certain medical conditions, such as diabetes mellitus, hypothyroidism, gout, mucopolysaccharidosis, and hyperlipidemia, pose the risk of tarsal tunnel syndrome. Some measures to manage the risk factors are as follows.
- Regular exercises, including walking, aerobics, and stretching ankles, help control all the causative conditions.
- Formulating food habits prevents worsening the conditions. For example, avoiding purine-rich food and red meat helps control gout.
- Healthy habits that improve hypertension prevent the development of abnormal medical conditions and reduce the risk of tarsal tunnel syndrome.
Conclusion
Tarsal tunnel syndrome affects all age groups but is predominant in the population susceptible to trauma to the foot and ankle. Walking patterns and intensity and frequency of weight-bearing activities influence the biomechanical aspects of ankles and feet.
Devising daily activities, including resting and exercises, helps manage tarsal tunnel syndrome. Though over-the-counter medications reduce symptoms, medical attention from an orthopedic doctor prevents complications and the progression of neuropathy.