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Tarsal Tunnel Syndrome
Jeff Wang, MD, MPH
J. Herbert Stevenson, MD
image BASICS
DESCRIPTION
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 (the tarsal tunnel)
Pregnancy Considerations
  • Tarsal tunnel syndrome can occur during pregnancy, typically secondary to local compression caused by fluid retention and volume changes (1).
  • Care is supportive. Most cases resolve after pregnancy.
EPIDEMIOLOGY
  • Women are slightly more affected than men (56%).
  • All postpubescent ages are affected.
ETIOLOGY AND PATHOPHYSIOLOGY
  • The posterior tibial nerve passes through the tarsal tunnel, which is formed by three osseus structures—sustentaculum tali, medial calcaneus, and medial malleolus—covered by the laciniate ligament.
  • Compression of the posterior tibial nerve within the tarsal tunnel results in decreased blood flow, ischemic damage, and resultant symptoms (1).
  • Chronic compression can destroy endoneurial microvasculature, leading to edema and (eventually) fibrosis and demyelination (2).
  • Increased pressure in the tarsal tunnel is caused by a variety of mechanical and biochemical mechanisms. The specific cause for compression is identifiable in only 60-80% of patients (1).
  • Three general categories: trauma, space-occupying lesions, deformity (1)
    • Trauma including displaced fractures, deltoid ligament sprains, or tenosynovitis
    • Varicosities
    • Hindfoot varus or valgus
    • Fibrosis of the perineurium
  • Other causes:
    • Osseous prominences
    • Ganglia; lipoma; neurolemmoma
    • Inflammatory synovitis
    • Pigmented villonodular synovitis
    • Tarsal coalition
    • Accessory musculature
  • In patients with systemic disease (e.g., diabetes), the “double crush” syndrome refers to the development of a second compression along the same nerve at a site of anatomic narrowing in patients with previous proximal nerve damage (3).
  • Tarsal tunnel decompression may improve sensory impairment and restore protective sensation in diabetic peripheral neuropathies if there is nerve entrapment at the tarsal tunnel.
RISK FACTORS
  • Tarsal tunnel syndrome is associated with certain occupations and activities involving repetitive weight bearing on the foot and ankle (jogging, dancing).
  • Other possible risk factors include (4):
    • Diabetes
    • Systemic inflammatory arthritis
    • Connective tissue disorders
    • Obesity
    • Varicosities
    • Heel varus or valgus
    • Bifurcation of the posterior tibial nerve into medial and lateral plantar nerves proximal to the tarsal tunnel
image DIAGNOSIS
Tarsal tunnel syndrome is largely a clinical diagnosis, characterized by pain and paresthesias in a predictable distribution along the medial aspect of the ankle and plantar surface of the foot (1).
PHYSICAL EXAM
  • Foot alignment
    • Examine for hindfoot varus or valgus deformity.
    • Exaggerating heel dorsiflexion, inversion, or eversion may reproduce symptoms by stretching or compressing the posterior tibial nerve.
  • Palpate the tarsal tunnel and the course of the tibial nerve for tenderness and swelling.
  • Tinel sign: Percussion over the the tibial nerve may reproduce paresthesias that radiate distally.
  • Valleix sign: Percussion over the tibial nerve may produce paresthesias that radiate proximally.
  • Cuff test: Inflating a pneumatic cuff engorges varicosities and reproduces symptoms.
  • Compression test: Applying pressure to the tarsal tunnel for 60 seconds may reproduce symptoms.
  • Sensory examination
    • The medial calcaneal nerve usually is spared, but numbness and altered sensation may be present in the distribution of the medial or lateral plantar nerves.
    • Vibratory sensation and two-point discrimination are decreased early in the disease process.
  • Motor examination
    • Intrinsic foot muscle weakness (difficult to assess)
    • Rarely, weakness of toe plantar flexion may be present.
    • Atrophy of the abductor hallucis or abductor digiti minimi may be seen late in the disease process.
DIFFERENTIAL DIAGNOSIS
  • Peripheral neuropathies (diabetes, alcoholism, HIV, or drug related)
  • Inflammatory arthritis (rheumatoid arthritis)
  • Morton neuroma
  • Metatarsalgia
  • Subtalar joint arthritis
  • Tibialis posterior tendinitis/dysfunction
  • Plantar fasciitis
  • Plantar callosities
  • Peripheral vascular disease
  • Lumbar radiculopathy
  • Proximal injury or compression of the tibial branch of the sciatic nerve
DIAGNOSTIC TESTS & INTERPRETATION
Initial Tests (lab, imaging)
Routine lab tests help rule out other conditions that may mimic tarsal tunnel syndrome, including diabetic neuropathy, rheumatoid arthritis, thyroid dysfunction, or other systemic illnesses (5).
  • Routine weight-bearing radiographs, followed by CT (if necessary) to assess for fracture or structural abnormality
  • Consider evaluation of lumbar spine x-ray if double crush (injury to lumbar nerve results in compensatory injury to posterior tibial nerve) is suspected (5).
  • MRI: helps assess the tarsal tunnel for soft tissue masses or other sources of nerve compression before surgery (1)
  • Ultrasound: Gaining importance and with several advantages over MRI (6); can assess for tenosynovitis, ganglia, varicose veins, or lipomas (1)
Pediatric Considerations
MRI is recommended for evaluating pediatric tarsal tunnel syndrome to exclude neoplastic mass.
P.1013

Diagnostic Procedures/Other
Electrodiagnostic studies
  • Electromyography (EMG) of the intrinsic muscles of the foot can confirm the diagnosis of tarsal tunnel syndrome (7). A normal EMG does not exclude the diagnosis (false-negative rate is ˜ 10%) (1).
  • Nerve conduction studies may reveal slowed conduction of the tibial nerve.
  • Evaluate for proximal nerve compression, including a lumbar radiculopathy or a double crush phenomenon.
image TREATMENT
Conservative management is recommended, except for acute onset tarsal tunnel syndrome or in the setting of a known space-occupying lesion (excluding synovitis).
MEDICATION
First Line
  • Analgesics and anti-inflammatory medications
  • Local corticosteroid injection
  • Medications that alter neurogenic pain (tricyclic antidepressants, antiepileptic drugs, nerve blockers)
ADDITIONAL THERAPIES
  • Rest/immobilization
  • Taping and bracing
  • Orthotics or shoe modification
  • Physical therapy to strengthen the intrinsic and extrinsic muscles of the foot and to restore the medial longitudinal arch
  • Other modalities (stretching, US, massage, icing)
  • Compression stockings to decrease swelling
  • Weight loss for obese patients
SURGERY/OTHER PROCEDURES
  • Surgery is indicated (1,2,8).
    • If nonoperative measures fail following a 3- to 6-month trial
    • In the setting of acute tarsal tunnel syndrome
    • If a space-occupying lesion is identified
  • The surgical outcome is dependent on technique and postoperative management. 50-95% of cases have good to excellent outcomes.
  • At the time of surgery, assess focal swelling, scarring, or nerve abnormalities and look for a pathologic source of compression.
  • Postoperative management includes:
    • Non-weight-bearing splint until incision heals (2 to 3 weeks), followed by progressively increased weight-bearing and range of motion exercises
    • Rest, ice, compression, elevation to limit swelling
image ONGOING CARE
PATIENT EDUCATION
  • Discuss conservative and surgical options based on individual patient circumstance and preference.
  • A decision about surgical intervention should be made with a clear understanding risks, benefits, and potential adverse outcomes.
PROGNOSIS
Surgery is most helpful for:
  • Patients with a positive Tinel sign (3)[B]
  • Young patients
  • Short period between occurrence of symptoms and surgery <1 year (9)[B].
  • Localized space-occupying lesion (1)
  • No motor neuron involvement
REFERENCES
1. Ahmad M, Tsang K, Mackenney PJ, et al. Tarsal tunnel syndrome: a literature review. Foot Ankle Surg. 2012;18(3):149-152.
2. Dellon AL. The four medial ankle tunnels: a critical review of perceptions of tarsal tunnel syndrome and neuropathy. Neurosurg Clin N Am. 2008;19(4): 629-648.
3. Dellon AL, Muse VL, Scott ND, et al. A positive Tinel sign as predictor of pain relief or sensory recovery after decompression of chronic tibial nerve compression in patients with diabetic neuropathy. J Reconstr Microsurg. 2012;28(4):235-240.
4. Franson J, Baravarian B. Tarsal tunnel syndrome: a compression neuropathy involving four distinct tunnels. Clin Podiatr Med Surg. 2006;23(3):597-609.
5. Fantino O. Role of ultrasound in posteromedial tarsal tunnel syndrome: 81 cases. J Ultrasound. 2014;17(2):99-112.
6. Patel AT, Gaines K, Malamut R, et al. Usefulness of electrodiagnostic techniques in the evaluation of suspected tarsal tunnel syndrome: an evidencebased review. Muscle Nerve. 2005;32(2):236-240.
7. Sung KS, Park SJ. Short-term operative outcome of tarsal tunnel syndrome due to benign space-occupying lesions. Foot Ankle Int. 2009;30(8):741-745.
8. Reichert P, Zimmer K, Wnukiewicz W, et al. Results of surgical treatment of tarsal tunnel syndrome. Foot Ankle Surg. 2015;21(1):26-29.
9. Gould JS. Recurrent tarsal tunnel syndrome. Foot Ankle Clin. 2014;19(3):451-467.
Additional Reading
&NA;
  • Abouelela AA, Zohiery AK. The triple compression stress test for diagnosis of tarsal tunnel syndrome. Foot (Edinb). 2012;22(3):146-149.
  • Allen JM, Greer BJ, Sorge DG, et al. MR imaging of neuropathies of the leg, ankle, and foot. Magn Reson Imaging Clin N Am. 2008;16(1):117-131.
  • Gondring WH, Tarun PK, Trepman E. Touch pressure and sensory density after tarsal tunnel release in diabetic neuropathy. Foot Ankle Surg. 2012;18(4):241-246.
  • Imai K, Ikoma K, Imai R, et al. Tarsal tunnel syndrome in hemodialysis patients: a case series. Foot Ankle Int. 2013;34(3):439-444.
See Also
&NA;
Algorithm: Foot Pain
Codes
&NA;
ICD10
  • G57.50 Tarsal tunnel syndrome, unspecified lower limb
  • G57.51 Tarsal tunnel syndrome, right lower limb
  • G57.52 Tarsal tunnel syndrome, left lower limb
Clinical Pearls
&NA;
  • Tarsal tunnel syndrome typically presents with pain and tingling of the medical ankle and plantar foot.
  • Tinel sign is the most sensitive and specific physical examination test for diagnosing tarsal tunnel.
  • EMG cannot independently diagnose tarsal tunnel syndrome; it is used to confirm a clinical diagnosis.
  • Conservative management is recommended, except for patients with an acute onset tarsal tunnel syndrome or known space-occupying lesion.