Description

Tarsal tunnel syndrome is a compression neuropathy of the posterior tibial nerve as it passes behind the medial malleolus and under the flexor retinaculum (laciniate ligament) in the medial ankle, a region commonly known as “the tarsal tunnel.”
Pregnancy Considerations

• Tarsal tunnel syndrome can occur during pregnancy, typically secondary to local compression caused by fluid retention and volume changes.
• Care usually is supportive until after delivery because many cases resolve after pregnancy.

Epidemiology

• Women are slightly more affected than men (56%).
• Individuals in all postpubescent ages can be affected.

Risk Factors

• Several authors have associated tarsal tunnel syndrome with certain occupations and activities, especially those that involve repetitive weight bearing on the foot and ankle, like jogging (1) or dancing (2).
• Other possible risk factors include (3):
  • Diabetes
  • Systemic inflammatory arthritis
  • Connective tissue disorders
  • Obesity
  • Varicosities
  • Heel varus or valgus

Pathophysiology

• Tarsal tunnel syndrome is caused by compression of the tibial nerve within the tarsal tunnel, resulting in decreased blood flow and ischemic damage.
• Increased pressure in the confined space of the tarsal tunnel is caused by a variety of mechanisms, both mechanical and biochemical, all of which result in increased pressure on the posterior tibial nerve.
• Chronic compression can destroy endoneurial microvasculature, leading to edema and eventually fibrosis and demyelination (4).

Etiology

• The specific cause is identifiable in only 60–80% of patients (5); causes can be grouped into 3 categories: Trauma, space-occupying lesion, and deformity.
• Most common causes include (5):
  • Trauma
  • Varicosities
  • Hindfoot varus or valgus
  • Fibrosis of the perineurium
• Other causes of compression include:
  • Osseous prominences
  • Ganglia
  • Lipoma
  • Neurolemmoma
  • Inflammatory synovitis
  • Pigmented villonodular synovitis
  • Tarsal coalition
  • Accessory musculature
• In patients with a systemic disease such as diabetes, “double-crush” syndrome should be considered; this refers to the development of a 2nd compression along the same nerve at a site of anatomic narrowing in patients with previous proximal nerve damage (3).