Next Step: Advanced Imaging with MRI
Order MRI of the ankle without contrast immediately to evaluate for occult calcaneal fracture or bone bruise, as this is the reference standard for detecting injuries missed on radiographs in patients with persistent pain beyond one week. 1, 2
Why MRI Now
Your patient has failed the typical 2-week boot immobilization period with persistent calcaneal tenderness despite negative radiographs. This clinical scenario demands advanced imaging:
- MRI is the reference standard for identifying occult fractures with associated bone marrow edema patterns, particularly after trauma with persistent localized pain 1, 2
- Radiographs miss significant injuries: Studies show radiography has only 87% sensitivity for calcaneal fractures compared to CT, and MRI detects bone bruises and stress injuries that are completely invisible on plain films 1
- Timing matters: The American College of Radiology specifically recommends MRI when radiographs are negative but pain persists >1 week post-injury 2
What You're Looking For
The MRI will identify:
- Occult calcaneal fractures (stress fractures, trabecular injuries) that don't show cortical disruption on X-ray 1
- Bone bruises with bone marrow edema patterns from the high-energy MVC mechanism 1, 2
- Subtalar joint injuries including osteochondral fractures that are notoriously difficult to detect on radiographs 1
- Soft tissue pathology including ligamentous injuries, tendon tears, or bursitis that could explain persistent symptoms 1
Referral Timing
Do not refer to orthopedics or podiatry yet — get the MRI first to guide appropriate subspecialty referral:
- If MRI shows occult fracture or significant bone bruise: Refer to orthopedic surgery or podiatric foot and ankle surgery with imaging in hand 1
- If MRI shows isolated soft tissue injury: Continue conservative management with possible physical therapy referral 2
- The American College of Foot and Ankle Surgeons recommends referral at 6-8 weeks for heel pain only after appropriate conservative treatment has failed 1, 2
Critical Management Points While Awaiting MRI
- Continue boot immobilization until MRI results are available — do not advance weight-bearing with unexplained calcaneal tenderness 2
- NSAIDs for pain control (ibuprofen 400mg every 4-6 hours) 2
- Avoid complete non-weight-bearing unless pain is severe, as this causes muscular atrophy 2
Common Pitfall to Avoid
Never assume "just a bruise" with focal calcaneal tenderness after high-energy trauma (MVC) and negative X-rays. Calcaneal fractures from axial loading mechanisms are frequently occult on initial radiographs, and delayed diagnosis leads to prolonged disability and potential malunion 1. The 2-week mark with persistent focal tenderness is your clinical trigger for advanced imaging, not your trigger for discharge.