Tarsal Tunnel Syndrome
Tarsal tunnel syndrome is a painful condition of the foot caused by pressure on the posterior tibial nerve as it passes along a passage called the tarsal tunnel just below the bony bit on the inside of the ankle.
Symptoms include pain which is often described as a burning pain radiating into the arch of the foot, heel and sometimes the toes.
Pins and needles or numbness may be felt in the sole of the foot. Pain may be worse when running or when standing for long periods of time and often worse at night. The area under the medial malleolus on the inside of the ankle may be tender to touch.
A professional therapist may use tinels test to diagnose tarsal tunnel syndrome. This involves tapping the nerve just behind the medial malleolus or bony bit of the ankle with a rubber hammer. Pain indicates a positive test.
Sometimes it is initially mistaken for plantar fasciitis which also causes pain from the inside heel and throughout the arch of the foot. Neural symptoms (such as tingling or numbness) as well as the location of tenderness when touching the area should help to easily distinguish between the conditions.
Tarsal tunnel syndrome occurs when the posterior tibial nerve which passes down the inside of the ankle becomes compressed or trapped.
If you overpronate where your foot rolls in when you walk or run then this can contribute to compression of the nerve. Because overpronation is a key factor, it is common for the problem to occur in both feet at the same time.
The term anterior tarsal tunnel syndrome is sometimes applied to a rare entrapment of the deep peroneal nerve at the front of the ankle, although this is not strictly the same as symptoms appear on the top of the foot and radiate towards the 1st and 2nd toes.
Tarsal tunnel syndrome can be both idiopathic, meaning it occurs spontaneously for apparently no reason, or it can be associated with a traumatic injury. Causes include:
- Osteoarthritis at the ankle joint - possibly as a result of an old injury
- Rheumatoid arthritis
- Talonavicular coalition - fusing of two of the tarsal bones.
- A cyst or ganglion in the tarsal tunnel.
In people involved in running or running based sports, where the condition occurs spontaneously, then overpronation is the most frequent cause.
Rest from any aggravating activities and apply cold therapy whilst in the acute phase when the foot or ankle is painful and inflamed. Your Doctor may prescribe anti-inflammatory medication to help reduce pain and inflammation.
Once the initial pain and inflammation has gone then a full rehabilitation program which includes stretching and strengthening exercises for the foot can begin. Consult a foot specialist, podiatrist or physiotherapist who can assess this and biomechanical problems of the foot.
Nerve conduction studies may be done to confirm the diagnosis and indicate the location of the entrapment. An X-ray or MRI may also be useful to determine the presence of any other structures such as cysts, arthritis or a tarsal coalition.
If conservative treatment fails then a corticosteroid injection may be administered. For stubborn and persistent cases surgery may be required to decompress the nerve. The operation is undertaken to decompress the nerve by freeing the soft tissue structures in the area, creating more space for the nerve.
The success rate from tarsal tunnel syndrome surgery is mixed, with a high risk of complications. The procedure itself is very fast, although a complete recovery can take anywhere from a couple of weeks to a few months.