What is Plantar Fasciitis?
Plantar fasciitis is a degenerative condition of the plantar fascia at its origin on the calcaneus, not primarily an inflammatory process as the name suggests. 1, 2
Definition and Pathology
Plantar fasciitis is a musculoskeletal disorder affecting the fascial enthesis (the attachment point of the plantar fascia to the heel bone). Despite its "-itis" suffix implying inflammation, histological evidence consistently shows chronic degenerative processes with fibrosis and granulomatous changes rather than active inflammation 3, 1. This is a critical distinction that affects treatment approaches.
The condition manifests as heel pain and represents one of the most common orthopedic syndromes affecting both athletes and nonathletes 3.
What Causes Plantar Fasciitis?
Mechanical Factors (Primary)
The etiology is multifactorial but predominantly mechanical in origin 3, 1:
- Repetitive stress and overuse: The most commonly cited mechanism, involving microscopic tears at the fascial origin from repeated loading 1, 2
- Biomechanical abnormalities:
Patient-Related Risk Factors
- Obesity: Increases mechanical load on the plantar fascia 4
- Middle age: Peak incidence occurs in this demographic 4
- Increased walking activity: Many patients report heightened activity just before symptom onset 5
Alternative Mechanisms (Emerging Evidence)
Beyond the traditional tensile strain theory, newer research suggests additional pathomechanical factors 1:
- Stress-shielding phenomena
- Vascular and metabolic disturbances
- Free radical formation
- Hyperthermia effects
- Genetic factors: Increasingly recognized as contributory 2
Associated Conditions
- Rheumatologic diseases: PF can be linked to systemic inflammatory conditions 2
- Calcaneal apophysitis: The most common cause of heel pain specifically in adolescents 5
Important Clinical Caveat
The scientific support for arch mechanics as the sole cause remains equivocal despite abundant anecdotal clinical evidence 1. This reflects both the difficulty in measuring arch mechanics in vivo and suggests that tensile failure may not be the predominant pathomechanical feature. The true cause in individual patients may remain obscure or involve multiple contributing factors 4.
The condition's resistance to treatment and variable response to interventions likely reflects this multifactorial etiology, where no single causative mechanism explains all cases 4.