How is plantar fasciitis diagnosed and treated?

Diagnosis of Plantar Fasciitis

Plantar fasciitis is predominantly a clinical diagnosis based on characteristic history and physical examination findings, with imaging reserved only for cases persisting beyond 3 months or when the diagnosis is uncertain. 1, 2, 3

Clinical Diagnosis

Key History Features

• Stabbing, nonradiating heel pain that is worst with the first steps in the morning or after prolonged sitting/rest 3, 4
• Pain located on the proximal medioplantar surface of the foot (inferior heel) 3
• Pain that worsens at the end of the day with prolonged activity 3
• Risk factors include obesity, excessive foot pronation, prolonged standing, running, and limited ankle dorsiflexion 2, 3

Physical Examination Findings

• Point tenderness to palpation at the medial plantar calcaneal region, specifically at the proximal plantar fascial insertion on the anteromedial calcaneus 2, 3, 4
• Discomfort elicited by passive ankle/first toe dorsiflexion (windlass test) 2, 5
• Heel squeeze test can be performed to support diagnosis 5

Imaging Studies (When Indicated)

Initial Imaging

If diagnosis is unclear or symptoms persist beyond 3 months despite treatment, obtain weightbearing radiographs first. 1, 6, 7

• Weightbearing radiographs have 85% sensitivity and 95% specificity for evaluating thickened plantar fascia and fat pad abnormalities 6, 7
• Radiographs help exclude other pathologies such as calcaneal stress fractures 1, 6

Advanced Imaging for Persistent Cases

MRI is the most sensitive imaging study for definitive diagnosis when uncertainty remains after initial evaluation. 8, 1, 7

• MRI allows accurate characterization of the plantar fascia and adjacent soft tissues/bones 8, 1
• Key MRI findings include increased plantar fascia thickness and abnormal tissue signal 2

Ultrasound is an excellent alternative with 80% sensitivity and 88% specificity compared to MRI. 8, 1, 7

• US findings supporting diagnosis include:
  • Plantar fascia thickness >4mm (abnormal) 1
  • Abnormal focal echogenicity within the plantar fascia (69% accuracy) 7
  • Perifascial edema (78% accuracy) 7
  • Edema around the plantar fascia (60% accuracy) 7
• US elastography demonstrates even higher accuracy with 95% sensitivity and 100% specificity compared to conventional ultrasound 1, 7

Nuclear Medicine (Limited Role)

• Bone scan with SPECT/CT can differentiate plantar fasciitis from calcaneal stress or avulsion fractures through characteristic uptake patterns 8, 7
• However, MRI and ultrasound remain the most frequently used imaging modalities for heel pain 8

Critical Differential Diagnoses to Exclude

• Calcaneal stress fracture: presents with similar symptoms, requires imaging to differentiate 1, 6
• Tarsal tunnel syndrome: neurologic heel pain from nerve entrapment, may require electromyography or nerve conduction studies 1, 6
• Plantar fascia rupture: potential complication diagnosed with MRI or ultrasound 1, 6
• Calcaneal apophysitis: most common cause of heel pain in adolescents 1

Common Pitfalls

Always correlate MRI findings with clinical symptoms to avoid overcalling plantar fasciitis, as some imaging findings (such as plantar fascia thickening) can be seen in asymptomatic patients. 8, 1, 7 This is the most important caveat when interpreting imaging studies.

Do not routinely order imaging for typical presentations—diagnosis is clinical in the vast majority of cases, and imaging should be reserved for atypical presentations, diagnostic uncertainty, or failure to respond to 3 months of conservative treatment. 1, 2, 3