What are the signs and assessment findings of plantar fasciitis?

Signs and Assessment Findings of Plantar Fasciitis

The most definitive signs of plantar fasciitis include sharp pain with the first steps in the morning or after prolonged sitting, point tenderness at the origin of the plantar fascia on the medial tubercle of the calcaneus, and pain that can be elicited by passive ankle/first toe dorsiflexion. 1, 2

Clinical Presentation

• Sharp, stabbing, nonradiating pain in the proximal medioplantar surface of the foot that is worst with the first steps in the morning or after periods of rest 3
• Pain typically worsens at the end of the day after prolonged standing or activity 2
• Point tenderness at the origin of the plantar fascia on the medial tubercle of the calcaneus (primary diagnostic finding) 2
• Discomfort in the proximal plantar fascia can be elicited by passive ankle/first toe dorsiflexion 1

Risk Factors

• Obesity or increased body mass index 1, 3
• Limited ankle dorsiflexion and gastrocnemius tightness 2, 3
• Excessive foot pronation 1
• Excessive running or prolonged standing 1, 3
• Affects both sedentary individuals and athletic populations 1, 2

Diagnostic Imaging

• Weightbearing radiographs should be the initial imaging study for painful heel, with 85% sensitivity and 95% specificity when evaluating for thickened plantar fascia and fat pad abnormalities 4, 5
• MRI is the most sensitive imaging study for definitive diagnosis, especially in cases that don't respond to initial treatment 4
• Ultrasound shows good diagnostic accuracy with 80% sensitivity and 88% specificity compared to MRI 4
• US elastography demonstrates even higher sensitivity (95%) and specificity (100%) than conventional ultrasound 4
• Diagnostic imaging is rarely needed for initial diagnosis and should be reserved for recalcitrant cases or to rule out other heel pathologies 1

Diagnostic Algorithm

1. Clinical diagnosis based on history and physical examination findings 1, 2
2. If diagnosis is unclear or symptoms persist beyond 3 months despite treatment:
   • Obtain weightbearing radiographs to exclude other pathologies 4
   • Consider MRI for definitive evaluation when diagnosis remains uncertain 4
3. Ultrasonography findings that support diagnosis include:
   • Abnormal focal echogenicity within plantar fascia (69% accuracy) 4
   • Edema around plantar fascia (60% accuracy) 4
   • Perifascial edema (78% accuracy) 4
   • Increased plantar fascia thickness (>4mm is abnormal) 4, 1

Differential Diagnosis Considerations

• Calcaneal stress fracture 4
• Tarsal tunnel syndrome 5
• Fat pad atrophy 2
• Nerve entrapment 3
• Plantar fascia rupture 4

Common Pitfalls and Caveats

• MRI findings should always be correlated with clinical symptoms to avoid overcalling plantar fasciitis, as some findings can be seen in asymptomatic patients 4
• Plantar fasciitis is often incorrectly considered an inflammatory condition, when "plantar fasciopathy" is a more appropriate descriptor as the condition is primarily degenerative rather than inflammatory 3
• Diagnostic imaging should not replace a thorough clinical examination, as the diagnosis is predominantly clinical 3
• Failure to identify and address contributing factors (such as gastrocnemius tightness or excessive pronation) may lead to treatment failure 2