Definition:

  • Compressive neuropathy of posterior tibial nerve behind medial malleolus

Symptoms & Signs:

  • Poorly localized dysesthesias in plantar aspect of foot
  • Aggravated by activity, alleviated by rest
  • Often nocturnal pain
  • Burning
  • Tapping over tarsal tunnel = worsening symptoms (Tinel’s sign)
  • Decreased two-point discrimination sensation

Etiology:

  • Space occupying lesion in tarsal tunnel
  • Ganglion
  • Synovial cyst
  • Lipoma
  • Typically following severe
  • trauma from scarring or edema
  • Severe venous varicosities
  • Tenosynovitis
  • Tumor within nerve
  • Unknown, >50% cases idiopathic

Contents of the tarsal tunnel

Diagnosis:

  • History of tingling pain, burning in posterior tibial nerve distribution distribution
  • Positive Tinel’s sign
  • Electrodiagnostic studies –
  • sensory nerve conduction
  • velocity most sensitive
  • +/- MRI to demonstrate
  • space-occupying lesion
  • within tarsal tunnel

MRI demonstrating enhancing lesion within tarsal tunnel (arrows)

Treatment:

  • Anti-inflammatory medications
  • Steroid injection into tarsal tunnel
  • Aspiration of cyst or ganglion, recurrence is common
  • Immobilization in ankle-foot orthosis
  • Surgical release of tarsal tunnel for refractory cases