Tarsal tunnel syndrome

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.

For better understanding of normal anatomy of tarsal tunnel, please refer article - "tarsal tunnel".

Clinical presentation

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.

Pathology

Because the tarsal tunnel is a tight space,  volume-occupying lesions can cause symptoms.

Aetiology

• idiopathic (50% cases)¹
• ganglion cysts
• bone deformity after calcaneal fractures
• varicosities
• tenosynovitis of the flexor tendons
• tumours (e.g. neurilemmoma ⁶, lipoma)
• accessory or hypertrophied abductor hallucis muscle
• synovial hypertrophy
• hind-foot valgus¹
• post-traumatic fibrosis
• os trigonum²

Radiographic features

Ultrasound

May be able to demonstrate the presence of some of the aetiological factors listed above.

MRI

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.

See also

• medial ankle tendon mnemonic
• carpal tunnel syndrome
• sinus tarsi syndrome