Tarsal tunnel syndrome is a rare condition which involves the compression of a nerve that passes through the leg into the foot through a tunnel in the foot.
The nerve may become irritated as a result of it becoming stretched along its path of travel, or compressed in the channel/tunnel in which it travels.
The tarsal tunnel/channel is a hollow area found in the ankle joint. The tunnel is surrounded by the bones in the ankle joint and acts as a channel and allows other structures such as nerves or blood vessels to pass through to the foot.
The tunnel may be found just behind the ankle, or is found around the inner aspect of the heel. There may be abnormal pressure exerted onto the nerve which passes through the leg.
You may feel numbness, tingling sensation and pain in the foot and ankle. The condition may affect any individual of any age.
There are a number of conditions with similar symptoms hence an accurate diagnosis and an identification of the cause of the condition is beneficial in alleviating symptoms.
This also enhances management and prevents or minimises the chance of recurrence.
What are the risk factors?
The condition results from a compression from a nerve which passes through the back of your leg to the foot. The nerve goes through a small channel/tunnel in the ankle joint before ending up in the foot.
The channel is enclosed in a structure to shield other structures such as nerves which pass through it. Whenever the channel gets swollen or irritated, there may be likelihood for a compression to occur.
There are a varied range of risk factors, which includes ankle sprains, the condition may also be caused by bone spurs, excessive walking, standing or running. Individuals with flat feet may also develop this condition.
Other risk factor which narrows the space in the tunnel which leads to increased pressure on the nerve includes:
• Injuries such as fractures or dislocation in the ankle joint dislocation or stretch injuries
• Varicose veins
• Unsuitable footwear
• Weakness in the lower limbs or legs
• Other conditions such as arthritis
• Inappropriate or improper training habits
• Reduced flexibility or stiffness in the ankle joint
• High foot arch.
• Excessive weight could also be a risk factor for the condition
What are the symptoms?
The main symptoms of the condition include numbness, tingling sensation, and weakness in the foot, burning sensation in the ankle or in the foot and pain in the ankle or foot.
Sometimes the pain you experience may be an abrupt shooting pain. Individuals may also have pain or discomfort in the calf muscle, the heel, toes and the foot arch.
The symptoms may become severe in the morning when you wake up but may also worsen as the day progresses. Symptoms are usually present even when you are not engaged in any activity –when you are at rest.
The key to treating both conditions is an accurate diagnosis and determining the cause of the inflammation that has resulted in pain.
Other symptoms include:
• Slow onset of pain with prolonged walking
• Weakness and inability to curl toes or push the foot down, or turn the ankle inwards
• Limitations associated with prolonged walking and standing
• Gait dysfunction or difficulties
How is tarsal tunnel syndrome diagnosed?
The individual undergoes various tests to ascertain the diagnosis and its severity. The individual is asked questions relating to the onset of the symptoms, the activities which exacerbate or decreases the condition.
A physical examination is also conducted to identify areas of numbness, discomfort and weakness in the foot and ankle. Other investigations include x-rays to rule out other causes of your symptoms before a diagnosis is made.
The writer is a senior physiotherapist at the 37 Military Hospital.