What is tarsal tunnel syndrome?
Tarsal tunnel syndrome, as described in this and most other online articles, refers to posterior tarsal tunnel syndrome. This rare condition results from the entrapment of the posterior tibial nerve behind the inner ankle and causes pain near the inner ankle and at the bottom of the foot .
The even rarer anterior tarsal tunnel syndrome refers to the entrapment of the deep peroneal nerve at the site between the front of the lower leg and the top of the foot .
Symptoms and Signs
Symptoms of posterior tarsal tunnel syndrome can include :
- Burning or shooting pain, tingling or numbness behind or below the inner ankle, radiating to the medial side of the foot arch and, sometimes, heel or toes
- Pain aggravated by walking or applying pressure behind the inner ankle and relieved by rest
- Swelling around the inner ankle
- Muscle wasting on the medial side of the foot and a decreased ability to bend the toes downward or spread them (in severe cases)
The main symptoms of the anterior tarsal tunnel syndrome are pain and tingling at the top of the foot.
Causes and Risk Factors
Causes of posterior tarsal tunnel syndrome include [3,10,11]:
- Trauma due to repeated prolonged standing, walking, marathon running, sprinting, jumping or weightlifting
- Anatomical deformities, such as flat foot, that result in foot overpronation (excessive inward rolling)
- Abnormal tissue pressing upon the nerve: ganglion cyst, lipoma or another tumor, a bone spur (in osteoarthritis or rheumatoid arthritis), varicose veins, surgical scars, swollen tendons, fibrous tissue (in systemic lupus erythematosus or systemic sclerosis)
- Ankle swelling due to pregnancy, ankle sprain, hypothyroidism, gout, kidney or heart disease
- Tight shoes
Conditions Similar to Posterior Tarsal Tunnel Syndrome
Physical Examination [1,11]:
A doctor, usually an orthopedist, can make a diagnosis by the symptoms and signs, and pain and tingling triggered by provocative tests:
- Tinel’s test: tapping behind the inner ankle
- Kinoshita test: bending the foot upwards (flexion) and outwards (eversion)
- An X-ray can reveal bony spurs.
- Ultrasound  or magnetic resonance imaging (MRI) can reveal soft tissues pressing upon the nerve.
- Electromyography (EMG) and nerve conduction tests can help confirm the diagnosis.
The following can reduce pain :
- Cold packs wrapped in a towel for 15-20 minutes several times a day (in acute phase, up to a week)
- Relative rest: avoiding prolonged standing and walking, running and carrying heavy loads
- Wearing comfortable shoes
- Nonsteroidal anti-inflammatory drugs, such as ibuprofen
- Wearing a walking boot, lace-up ankle brace or custom functional foot orthotic
- Losing weight (if overweight)
A steroid injection into the tarsal tunnel can temporarily relieve pain. However, an injection, especially if repeated, may permanently damage the tibial nerve and decrease the outcome of subsequent surgery [8,9]. Shoe inserts may either improve or worsen the symptoms . Shoes with the insoles that are hard on the medial side can help prevent overpronation, though . Night splints may not have any long-term benefit .
Whirlpool massage and compression stockings may reduce ankle swelling and hence pressure on the nerve .
When the pain has gone, stretching and strengthening exercises for calf muscles, foot muscles and plantar fascia should be performed 3 times a day over a period of several weeks. More about exercises here.
Surgical treatment can be considered when physical therapy for 3-6 months does not help and when a compressing mass can be identified . Surgery includes the release (decompression) of the tibialis nerve. Recovery after surgery may take from several weeks to few months . The reported success rates of surgical treatment range from 44 to 91% [1,10]. Surgical complications, such as nerve damage or scaring, or numbness in the foot, may occur in up to 30% [4,5]. Surgery is more likely successful is performed early – within the first year of symptoms onset [7,10].
If the initial surgery is not effective, the subsequent surgery will less likely help [1,5].
The underlying anatomical abnormalities may also need to be treated surgically.
There is insufficient evidence about the effectiveness of the acupuncture, manual therapy, taping or ultrasound in the treatment of tarsal tunnel syndrome.
Prognosis is best after removal of the compressing mass, such as ganglion cyst . Symptoms may recur after insufficient surgical release .
Video 1. Tarsal tunnel syndrome: anatomy, symptoms, tests, treatment
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