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