(See also Overview of Foot Problems.)
The posterior tibial nerve runs down the back of the calf, through a fibrous canal (tarsal tunnel) near the heel, and into the sole of the foot. When tissues around the tarsal tunnel become inflamed, they can swell and press on the nerve (nerve compression), causing pain.
Disorders that can cause or contribute to tarsal tunnel syndrome include fracture, ankle swelling caused by heart failure or kidney failure, and an underactive thyroid gland (hypothyroidism). Also, disorders such as gout or rheumatoid arthritis cause inflammation in the joints. Poor foot posture may also contribute if the ankle rolls too far inward and stresses the nerve within the tarsal tunnel.
Pain, the most common symptom of tarsal tunnel syndrome, usually has a burning or tingling quality that may occur when a person stands, walks, or wears a particular type of shoe. Pain located around the ankle (usually on the inner side) and extending to the toes usually worsens during walking and is relieved by rest. As the disorder progresses, pain also may occur during rest.
To diagnose tarsal tunnel syndrome, a doctor manipulates the affected foot during a physical examination. For example, tapping the injured or compressed area just below the ankle bone often causes tingling (referred to as the Tinel sign), which may extend to the heel, arch, or toes.
Nerve conduction studies may be useful to determine the cause or extent of the injury, especially if foot surgery is being considered.
Injections of a corticosteroid/anesthetic mixture into the area may relieve pain. Nonsteroidal anti-inflammatory drugs (NSAIDs) may be used at first and may relieve some symptoms.
Other treatments include wrapping the foot and placing specially constructed devices in the shoe (orthoses).
When other treatments do not relieve the pain, surgery to relieve pressure on the nerve may be necessary.