Workup for Right Heel Pain in a Marathon Runner
Start with weightbearing radiographs of the foot as your initial imaging study, which should be obtained in all marathon runners presenting with heel pain to exclude fractures, bone pathology, and establish a baseline for plantar fasciitis diagnosis. 1
Clinical Assessment Focus
Before imaging, identify the specific pain location and characteristics:
- Plantar heel pain (most common in runners): Suggests plantar fasciitis, characterized by pain with first steps in morning or after prolonged sitting, with tenderness at the calcaneal tuberosity that increases with passive toe dorsiflexion 1, 2
- Posterior heel pain: Indicates Achilles tendinopathy or retrocalcaneal bursitis 1
- Lateral heel pain: Consider calcaneal stress fracture, particularly in athletes with recent increased training volume 1
- Diffuse heel pain with compression tenderness: Highly suspicious for calcaneal stress fracture 1
Initial Imaging: Weightbearing Radiographs
Weightbearing radiographs are mandatory as the first imaging study, with sensitivity of 85% and specificity of 95% for plantar fasciitis when showing thickened plantar fascia and fat pad abnormalities. 1, 3 This modality also effectively excludes:
- Calcaneal stress fractures (sensitivity 12-56%, specificity 88-96%) 1
- Bone tumors or infections 1
- Haglund's deformity 1
- Calcaneal spurs 3
Advanced Imaging When Radiographs Are Negative or Equivocal
For Suspected Plantar Fasciitis (Most Common in Runners)
Order MRI foot without IV contrast as the next study if symptoms persist beyond 6-8 weeks of conservative treatment or if diagnosis remains uncertain. 1, 3, 4 MRI is the most sensitive imaging modality for plantar fasciitis, allowing accurate characterization of the plantar fascia thickness, focal echogenicity changes, perifascial edema, and excluding plantar fascia tears. 3, 4
Ultrasound is an acceptable alternative with 80% sensitivity and 88% specificity compared to MRI, offering the advantage of dynamic examination and direct clinical correlation. 1, 3, 4 US elastography demonstrates even higher accuracy (95% sensitivity, 100% specificity) compared to conventional ultrasound. 3
For Suspected Stress Fracture
If clinical examination suggests calcaneal stress fracture (compression tenderness at lateral calcaneal wall, recent training increase), and radiographs are negative:
- MRI without contrast is the preferred study, as stress fractures often appear on MRI before becoming visible on radiographs 1
- Three-phase bone scan with SPECT/CT is an alternative that can differentiate plantar fasciitis from calcaneal stress/avulsion fractures based on characteristic uptake patterns 3
For Suspected Nerve Entrapment
If symptoms include tingling, burning, or numbness suggesting Baxter's neuropathy (inferior calcaneal nerve entrapment):
- MRI without contrast is the primary study, demonstrating denervation changes in the abductor digiti minimi muscle 1, 5
- Ultrasound can visualize the nerve anterior to the calcaneus and assess for compression 1
Critical Pitfalls to Avoid
Do not routinely order MRI as the initial study. A retrospective study of 141 patients with clinical plantar fasciitis found MRI was normal in 20.7% of cases, and only 1.3% had diagnoses other than plantar fasciitis, with no sinister pathology identified. 6 This demonstrates that careful clinical assessment with initial radiographs is sufficient in most cases.
Always correlate MRI findings with clinical symptoms, as some imaging findings can be present in asymptomatic individuals. 3 MRI should be reserved for recalcitrant cases or when other pathology needs exclusion. 4
Avoid non-weightbearing radiographs, as they may underestimate the degree of pathology and malalignment. 5
When to Escalate Imaging
Proceed to advanced imaging if: