What is the recommended assessment and treatment approach for plantar fasciitis?

Assessment for Plantar Fasciitis

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

Clinical Diagnosis

History

• Stabbing, nonradiating pain on the proximal medioplantar surface of the foot, worst with first steps in the morning or after prolonged sitting 1
• Pain typically worsens at the end of the day after prolonged standing or walking 1
• Risk factors to identify include obesity, excessive foot pronation, excessive running, prolonged standing, limited ankle dorsiflexion, and middle age 2, 1

Physical Examination

• Tenderness to palpation of the proximal plantar fascial insertion at the anteromedial calcaneus is the primary physical finding 1, 3
• Discomfort can be elicited by passive ankle and first toe dorsiflexion, which stretches the plantar fascia 2
• Examine for biomechanical abnormalities including tight Achilles tendon, pes cavus, and pes planus 4

Imaging Studies

Initial Imaging Approach

• Diagnostic imaging is rarely needed for initial diagnosis 2
• If diagnosis is unclear or symptoms persist beyond 3 months despite treatment, obtain weightbearing radiographs first 5, 6
  • Radiographs have 85% sensitivity and 95% specificity for evaluating thickened plantar fascia and fat pad abnormalities 5, 6
  • This helps exclude other pathologies such as calcaneal stress fracture or tarsal tunnel syndrome 5

Advanced Imaging for Recalcitrant Cases

• MRI is the most sensitive imaging study for definitive diagnosis when uncertainty persists 5, 6

  • MRI allows accurate characterization of the plantar fascia and adjacent soft tissues/bones 6
  • Important caveat: MRI findings must be correlated with clinical symptoms, as some findings can be seen in asymptomatic patients 6

• Ultrasound is a reasonable and inexpensive alternative for patients with pain persisting beyond 3 months 1

  • Sensitivity of 80% and specificity of 88% compared to MRI 5, 6
  • Diagnostic findings include abnormal focal echogenicity within plantar fascia, perifascial edema, and increased plantar fascia thickness >4mm 5
  • US elastography shows even higher accuracy with 95% sensitivity and 100% specificity 5, 6

Differential Diagnosis to Exclude

• Calcaneal stress fracture (can present with similar symptoms) 5
• Tarsal tunnel syndrome (neurogenic cause of heel pain) 5
• Plantar fascia rupture (potential complication) 5
• Other causes of subcalcaneal pain 4

Diagnostic Algorithm Summary

1. Start with clinical diagnosis based on characteristic morning pain and medial calcaneal tenderness 2, 1
2. No imaging needed if presentation is typical and patient responds to initial conservative treatment 2
3. If symptoms persist >3 months or diagnosis uncertain: obtain weightbearing radiographs 5, 6
4. If radiographs are negative but suspicion remains high: proceed to ultrasound or MRI 5, 6, 1