What Causes Heel Spurs
Heel spurs develop as a bony response to chronic mechanical stress and inflammation at the calcaneal tuberosity, most commonly from repetitive trauma, abnormal foot biomechanics (particularly excessive pronation), and chronic plantar fascia tension. 1, 2
Primary Causative Mechanisms
The etiology of calcaneal spurs involves multiple interconnected theories:
- Repetitive microtrauma from chronic mechanical stress at the plantar fascia insertion site triggers reactive bone formation 3
- Abnormal pronation creates excessive tension and pulling forces at the calcaneal attachment, leading to inflammation and subsequent bone deposition 2
- Chronic plantar fasciitis with persistent inflammation at the heel stimulates osteoblastic activity and spur formation 4, 3
- Vertical compression forces from weight-bearing activities contribute to bone remodeling at the calcaneal tuberosity 3
Key Risk Factors and Associations
Several factors increase the likelihood of developing heel spurs:
- Age-related changes in tissue elasticity and bone metabolism make spurs more common in older adults 3
- Increased body weight places greater mechanical stress on the plantar fascia insertion 3
- Inflammatory arthritides (including ankylosing spondylitis) can trigger spur formation through systemic inflammatory processes 3, 5
- Altered foot biomechanics from improper footwear, flat feet, or high arches create abnormal stress distribution 2
- Increased walking activity or changes to harder walking surfaces can precipitate symptoms 6, 7
Important Clinical Distinctions
The spur itself is not necessarily the source of pain—rather, inflammation of surrounding soft tissues and possible nerve compression cause the symptoms. 1 This is a critical concept because:
- Many patients have radiographically visible heel spurs without any pain 1, 3
- The pain typically originates from plantar fasciitis and associated soft tissue inflammation rather than the bony prominence itself 4
- Treatment focuses on addressing the inflammatory process and biomechanical abnormalities, not the spur 1, 2
Anatomical Considerations
- Inferior calcaneal spurs project forward from the plantar aspect of the calcaneal tuberosity, typically associated with plantar fascia tension 3, 5
- Posterior calcaneal spurs develop at the Achilles tendon insertion on the back of the heel 5
- The spurs represent fibrocartilaginous and bony outgrowths at areas of chronic tensile stress 3, 8
Common Clinical Pitfall
Do not assume that the presence of a heel spur on radiograph automatically explains a patient's heel pain—always evaluate for other causes including calcaneal stress fracture (positive calcaneal squeeze test), nerve entrapment (burning/tingling symptoms), Achilles tendonitis, or retrocalcaneal bursitis based on specific pain location and examination findings. 6, 7