What imaging should be ordered if pain persists after a fall with negative X-rays (radiographs) for fractures?

Imaging for Persistent Pain After Negative X-rays for Fractures

For patients with persistent pain after a fall and negative radiographs, CT without contrast should be the next imaging study, followed by MRI if clinical concern persists despite negative CT findings. 1

Diagnostic Algorithm for Persistent Post-Traumatic Pain

Step 1: Initial Assessment

• Negative radiographs but persistent pain suggests possible occult fracture
• Location of pain should guide imaging selection
• Weight-bearing status and functional limitations are key clinical indicators

Step 2: Next Imaging Study Selection

For Hip/Pelvic Pain:

1. CT without IV contrast as the first advanced imaging study

   • Advantages: Faster acquisition, greater availability, lower cost 1
   • Detects occult fractures in 24.1% of cases with negative radiographs 1
   • Changes management in approximately 20% of cases 1
   • Sensitivity 79-94%, specificity 100% 1, 2

2. MRI without contrast if CT is negative but clinical suspicion remains high

   • Superior sensitivity (99%) for detecting occult fractures 2
   • Better visualization of bone marrow edema and soft tissue injuries 2
   • Required when CT findings are negative or equivocal but clinical concern persists 1

For Foot/Ankle Pain:

• MRI without IV contrast is the preferred next imaging study 1
• CT without contrast is an alternative, particularly for midfoot pain of suspected osseous origin 1

Step 3: Interpretation and Follow-up

• Positive findings: Implement appropriate treatment based on fracture characteristics
• Negative advanced imaging with persistent symptoms: Consider other pain generators (soft tissue injury, nerve entrapment)

Important Clinical Considerations

Strengths of Different Modalities

• CT: Excellent for detecting cortical disruption and fracture lines, faster acquisition time 1
• MRI: Superior for detecting bone marrow edema, soft tissue injuries, and early stress reactions 2
• Bone scan: Generally not recommended as initial advanced imaging due to delay in positivity (24-72 hours) and lower specificity 1, 3

Common Pitfalls to Avoid

1. Relying solely on radiographs when clinical suspicion is high

   • False-negative rates of plain radiographs can be significant 4
   • Occult fractures may not be visible on initial radiographs

2. Stopping at CT if negative but symptoms persist

   • CT may miss non-displaced fractures and bone marrow edema 2
   • MRI should follow negative CT when clinical suspicion remains high 1, 2

3. Delaying advanced imaging

   • Early diagnosis decreases fracture-related morbidity 1
   • Prompt diagnosis allows for appropriate weight-bearing instructions and treatment planning

4. Using bone scans as first-line advanced imaging

   • Initial bone scans can be falsely negative 3
   • Requires 24-72 hours for optimal sensitivity 2

By following this evidence-based approach, clinicians can efficiently diagnose occult fractures, reduce patient morbidity, and optimize outcomes through appropriate and timely management.