The tarsal tunnel is an area behind the bump on the inside of the ankle. A nerve called the posterior tibial nerve passes in this area, behind the ankle bone and spreads out to provide sensation to the bottom of the foot and the first three toes. It is bordered by the ankle bones on the inside and a strap-like ligament on top.
If the area around the nerve becomes tight due to swelling, cysts, tendonitis, flat feet or bone spurs, the nerve may become pinched. Sometimes injuries, tumors, varicose veins or some unusual diseases cause buildup of other fluid or tissue in the area.
The pain may be felt in the sole of the foot into the toes. It may feel like an ache, burning, numbness or tingling. Tarsal tunnel syndrome often will be painful walking or driving a car. Pain may also go from the ankle up the leg into the calf.
Any condition which puts unusual pressure on the nerve in the tarsal tunnel may cause tarsal tunnel syndrome. Usually this is due to mechanical compression or swollen arthritic tissue in the area. Flat feet or pronation are risk factors. If the ankle loses support, such as from a torn tendon (a complication of rheumatoid arthritis) the nerve may become pinched. Excessive or unusually vigorous or excessive sports, (especially jumping) may cause tendinitis and swelling resulting in compression of the nerve. Inflammation and swelling from arthritic diseases such as rheumatoid arthritis also will pinch or crowd the nerve. Sometimes conditions causing fluid to build up in the tarsal tunnel such as injuries, ganglion cysts, obesity or pregnancy will compress the nerve.
If pain runs under the foot side and into all of the toes especially when walking or standing in certain positions, there is a good chance that tarsal tunnel syndrome is present. It may be confused with plantar fasciits, another cause of pain over the bottom of the foot. Tapping behind the bone on the inside of the ankle may cause pain to shoot into the foot or lower leg. Specialized nerve conduction velocity testing (NCV) may confirm the diagnosis.
Treatment depends upon the cause and severity of the symptoms. Usually proper foot support (orthotics), a modification of activities and physical therapy are helpful. Over the counter medications such as Tylenol (generic = acetaminophen) Aleve (generic = naproxen), Motrin (generic = ibuprofen) or aspirin. In addition, prescription strength medications called non-steroidal anti-inflammatory medications (NSAIDs for short) may be recommended. Some of the more commonly prescribed of these include medications such as Ibuprofen, Naprosyn and Celebrex. For burning pain, Neurontin or Lyrica may provide relief, and sometimes an adhesive patch containing lidocaine is helpful. If these are not successful, cortisone shots to reduce the swelling around the nerve, or surgery to release nerve compression may be considered. If rheumatoid arthritis is causing tarsal tunnel syndrome, specific treatment prescribed by a rheumatologist will reduce swelling in the area, and reduce the pain.