Tarsal tunnel syndrome (TTS) refers to an entrapment neuropathy of the posterior tibial nerve or of its branches within the tarsal tunnel. This condition is analogous to carpal tunnel syndrome. While carpal tunnel syndrome is usually bilateral, tarsal tunnel syndrome is unilateral.
The most common symptoms are pain and paresthesia in the toes, sole, or heel and the main finding at physical examination is the Tinel sign (distal paresthesias produced by percussion over the affected portion of nerve).
Electromyography and nerve conduction studies are useful in confirming the diagnosis.
Because the tarsal tunnel is a tight space, volume-occupying lesions can cause symptoms.
- idiopathic (50% cases) 1
- ganglion cysts
- bone deformity after calcaneal fractures
- tenosynovitis of the flexor tendons
- tumours (e.g. neurilemmoma 6, lipoma)
- accessory or hypertrophied abductor hallucis muscle
- synovial hypertrophy
- hind-foot valgus 1
- post-traumatic fibrosis
- os trigonum 2
May be able to demonstrate the presence of some of the aetiological factors listed above.
MR imaging clearly depicts the bones, soft-tissue contents, and boundaries of the tarsal tunnel as well as the different pathologic conditions responsible for tarsal tunnel syndrome.
MR imaging can also aid in determining whether treatment should be conservative (e.g. tenosynovitis) or surgical (e.g. space-occupying lesions).
History and etymology
The term was first specifically described by C Keck and S J S Lam in 1962 3.
Treatment and prognosis
Conservative management - orthosis, local injection, anti-inflammatory medications, and tricyclic antidepressants (TCA).
Surgical management - decompressive surgery.
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- 4. Fantino O, Coillard JY, Borne J et-al. Ultrasound of the tarsal tunnel: Normal and pathological imaging features. J Radiol. 2011;92 (12): 1072-80. doi:10.1016/j.jradio.2011.03.026 - Pubmed citation
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