Tarsal Tunnel Syndrome
Last updated: October 30, 2014
ICD9 Code: 355.5
ICD10 Code: G57.51 right lower limb; G57.52 left lower limb
Definition: To enter the foot, the posterior tibial nerve must pass through the tarsal tunnel beneath a flexor retinaculum located just below the medial malleolus of the ankle. Compression of the nerve at this location may lead to local pain or numbness.
Risk Factors: Local trauma (e.g., fracture), body habitus (e.g., valgus foot deformity), and repetitive use or injury are risk factors.
Demographics: Women are affected slightly more frequently than men.
Cardinal Findings: Patients typically present with numbness, burning pain, or paresthesias of the toes or the sole of the foot. Symptoms may be noted after a night’s sleep or even awaken the patient. A positive Tinel test is suggested by repetitive tapping over the flexor retinaculum (posterior to the medial malleolus) to reproduce symptoms.
Diagnostic Tests: Definitive diagnosis may be made by demonstration of prolonged motor and sensory latencies on nerve conduction testing.
Differential Diagnosis: Other peripheral neuropathies (e.g., those related to diabetes mellitus and alcoholism) are in the differential diagnosis. In those conditions, symptoms and findings at examination more commonly affect the entire foot, in the so-called stocking-glove pattern typical of diffuse neuropathies.
Therapy: Initial treatment may involve conservative measures, such as selecting optimal footwear or orthoses. Some physicians use injections of corticosteroids directly into the flexor retinaculum in an attempt to decrease local swelling and thereby relieve the compression. In refractory patients, surgical decompression is indicated.
Kuritz HM, Sokoloff TH. Tarsal tunnel syndrome. J Am Podiatry Assoc 1975;65:825–840.PMID:1159278