Can a calcaneal (heel bone) spur cause tarsal tunnel syndrome?

Can a Calcaneal Spur Cause Tarsal Tunnel Syndrome?

While a calcaneal spur can potentially contribute to tarsal tunnel syndrome by causing compression of the tibial nerve or its branches within the tarsal tunnel, it is not a common direct cause of this condition.

Understanding Tarsal Tunnel Syndrome

Tarsal tunnel syndrome (TTS) is a compressive neuropathy of the posterior tibial nerve or its branches within the tarsal tunnel, which is formed by the flexor retinaculum with the floor composed of the distal tibia, talus, and calcaneal bones 1.

• TTS can present with numbness, burning, and painful paresthesia in the heel, medial ankle, and plantar surface of the foot 1, 2
• Diagnosis is typically made through a combination of clinical history, imaging tests, nerve conduction studies, and electromyography 1
• A positive Tinel's sign (tingling sensation when tapping over the nerve) is often present 2, 3

Relationship Between Calcaneal Spurs and TTS

• Focal compressive neuropathy of TTS can originate from anything that physically restricts the volume of the tarsal tunnel 2
• Bony lesions, including calcaneal spurs, can potentially cause compression of the tibial nerve within the tarsal tunnel 2
• The American College of Foot and Ankle Surgeons guidelines recognize that neurologic heel pain can occur due to irritation or entrapment of nerves innervating the heel 4

Documented Cases of Bony Structures Causing TTS

• Case reports have documented TTS caused by bony abnormalities such as:
  • Posterior facet talocalcaneal coalition 5
  • Uncommon ossicles of the talus 6
• These cases demonstrate that bony structures can indeed cause compression of the tibial nerve leading to TTS 5, 6

Diagnostic Approach for Suspected TTS

When TTS is suspected in a patient with heel pain:

• Radiography of the foot is usually the appropriate initial imaging study 4
• If neurologic heel pain is suspected, subspecialist referral for evaluation and diagnostic testing should be considered 4
• Diagnostic studies may include electromyography, nerve conduction velocity studies, and MRI 4
• MRI allows visualization of both the bony structures (including calcaneal spurs) and the soft tissues, making it valuable for assessing nerve compression 4

Management Options

If TTS is diagnosed and a calcaneal spur is identified as a contributing factor:

• Conservative treatment is typically the first approach, including:

  • Activity modification 1, 2
  • NSAIDs for pain relief 7
  • Physical therapy 7, 2
  • Orthotic devices 7
  • Corticosteroid injections into the tarsal tunnel 1, 2

• Surgical intervention may be considered when:

  • Conservative treatment fails 1, 2
  • There is clear identification of the cause of entrapment (such as a calcaneal spur) 1
  • Surgical treatment involves releasing the flexor retinaculum and addressing any compressive structures 1, 2

Important Considerations and Pitfalls

• TTS is often underdiagnosed, with symptoms potentially overlapping with other causes of heel pain 1, 3
• A differential diagnosis should include plantar fasciitis, lumbosacral radiculopathy, rheumatologic diseases, and stress fractures 1
• Delayed diagnosis can lead to permanent nerve damage in severe or long-standing cases 3
• A positive Tinel's sign before surgery is a strong predictor of surgical relief after decompression 1

Conclusion

While calcaneal spurs can theoretically contribute to tarsal tunnel syndrome by causing compression of the tibial nerve, this is not among the most common causes. When evaluating a patient with heel pain and neurological symptoms, a comprehensive diagnostic approach including appropriate imaging and nerve conduction studies is essential to determine if a calcaneal spur is directly involved in causing TTS.