Imaging Guidelines for Foot Trauma

Initial Imaging Approach

The American College of Radiology recommends radiographs as the mandatory first-line study for acute foot trauma, with weight-bearing views essential when possible 1, 3
Weight-bearing radiographs have 99% sensitivity for detecting foot fractures when Ottawa rules are positive 3
Non-weight-bearing films are unreliable for detecting subtle injuries, particularly Lisfranc injuries 1, 2, 4
Bilateral imaging helps identify subtle malalignment by comparison with the uninjured side 3, 2, 4

The American College of Radiology suggests CT as the primary advanced imaging technique for acute hyperflexion injuries and high-energy polytrauma, especially when patients cannot bear weight 1, 2, 4
CT is recommended for complex fractures requiring preoperative planning, particularly involving multiple metatarsal and cuneiform fractures 1, 4
CT is useful for demonstrating the full extent of osseous injury and associated fractures in Lisfranc injuries 1, 2, 4
Approximately 25% of midfoot fractures identified on CT are missed on radiographs alone in polytrauma patients 4
CT is superior to MRI for detecting nondisplaced fractures and subtle osseous injuries, and for identifying water-rich fresh wood foreign bodies (63% sensitivity, 98% specificity) 4, 5, 6

The American College of Radiology recommends MRI for suspected Lisfranc injury with normal radiographs, particularly for purely ligamentous injuries without diastasis 1, 2, 4
MRI is useful for detecting occult fractures and bone stress injuries not visible on radiographs 1
MRI is the preferred modality for evaluating soft tissue injuries, including ligaments, tendons, and the capsuloligamentous complex 1
MRI has high correlation with intraoperative findings for unstable Lisfranc injuries, and 3-D volumetric acquisitions are superior to standard orthogonal imaging for Lisfranc ligamentous complex evaluation 1, 2, 4
MRI demonstrates osseous injuries not visible radiographically, including high-grade contusions associated with prolonged recovery in athletes, and is excellent for evaluating osteomyelitis in diabetic foot complications (77-100% sensitivity, 80-100% specificity) 1, 2

Obtain weight-bearing radiographs, including AP view with 20° craniocaudal angulation for suspected Lisfranc injuries, and bilateral views for comparison 3, 2, 4
If radiographs show complex fractures or polytrauma, proceed directly to CT for complete osseous evaluation and surgical planning 1, 2, 4
If radiographs are negative but clinical suspicion remains high, choose CT for suspected occult fractures in high-energy mechanisms or inability to bear weight, or choose MRI for suspected soft tissue injuries, ligamentous Lisfranc injuries, or when tendon/plantar plate pathology is suspected 1, 4, 5, 2

Never rely solely on non-weight-bearing radiographs for suspected Lisfranc injuries, as this leads to missed diagnoses 1, 2, 4
In diabetic patients with neuropathy, standard clinical tests are unreliable and patients may bear weight despite fractures—image more liberally 3, 2, 7
Do not use CT or MRI as first-line imaging when radiographs are appropriate and sufficient 1, 3
Remember that conventional radiographs including weight-bearing images are not sufficient for routine workup of acute hyperflexion injuries—CT should be primary 1, 4

For foreign body detection, CT is superior to MRI (63% vs 58% sensitivity), particularly for radiopaque materials 5, 6
MRI and ultrasound have similar sensitivity for acute soft-tissue trauma including ligamentous and tendinous disruption 1
Post-traumatic arthritis occurs in approximately 25% of Lisfranc injuries despite anatomic reduction, requiring long-term radiographic surveillance 2