What is Plantar Fasciitis?
Plantar fasciitis is a common, self-limiting condition characterized by chronic degenerative changes (not primarily inflammation) of the plantar fascia at its origin on the medial tubercle of the calcaneus, resulting from repetitive stress and mechanical overload. 1, 2
Pathophysiology and Nature of the Condition
- The condition involves chronic degenerative processes rather than acute inflammation, as demonstrated by histologic findings in affected patients 2
- It results from repetitive stress to the plantar fascia at its origin on the medial tubercle of the calcaneus 3
- The plantar fascia is the connective tissue structure extending from the heel bone through the arch to the toes 1
Epidemiology and Risk Factors
- Plantar fasciitis affects more than 1 million persons per year in the United States, with two-thirds seeking care from their family physician 1
- It is the most common cause of chronic heel pain in adults and accounts for 10% of running injuries 4, 3
- The condition affects both sedentary and athletic populations, primarily afflicting middle-aged and elderly individuals as well as athletes 1, 4
Key risk factors include:
- Obesity 1
- Excessive foot pronation 1
- Excessive running and prolonged standing 1
- Gastrocnemius (calf muscle) tightness 3
- Reduced ankle dorsiflexion 2
- Rheumatologic diseases and genetic factors 2
Clinical Presentation
The hallmark symptom is aching plantar heel pain that is worst with the first steps in the morning or after prolonged sitting. 1, 3
Diagnostic clinical features include:
- Sharp pain with palpation of the medial plantar calcaneal region (point tenderness at the origin of the plantar fascia on the medial tubercle of the calcaneus) 1, 3
- Discomfort in the proximal plantar fascia elicited by passive ankle/first toe dorsiflexion 1
- Pain that can be triggered and aggravated by prolonged standing, walking, and running 5
Diagnostic Approach
- Diagnosis is primarily clinical, based on history and physical examination 1, 3
- Diagnostic imaging is rarely needed for initial diagnosis 1
- If diagnosis is unclear or symptoms persist beyond 3 months, obtain weightbearing radiographs (85% sensitivity, 95% specificity) to exclude other pathologies 6
- MRI is the most sensitive imaging study when diagnosis remains uncertain, allowing accurate characterization of the plantar fascia and adjacent structures 7, 6
- Ultrasound shows good sensitivity (80%) and specificity (88%), with findings of increased plantar fascia thickness and hypoechoic changes 7, 6, 2
Important caveat: MRI findings should always be correlated with clinical symptoms, as some imaging abnormalities can be seen in asymptomatic patients 6