What is the appropriate management for a suspected missed fracture?

Management of Suspected Missed Fracture

When a fracture is suspected but initial radiographs are negative, MRI without contrast is the preferred next imaging study for most anatomic sites, offering near 100% sensitivity for occult fractures and superior soft-tissue evaluation compared to all other modalities. 1

Initial Imaging Approach

• Standard radiographs remain the mandatory first-line imaging for any suspected fracture, despite their limited sensitivity (30-70% even after 10-14 days of symptom onset). 1
• If initial radiographs are conclusive for fracture, no further imaging is needed. 1
• Most missed fractures result from perceptual errors rather than technical limitations, with commonly missed sites including the scaphoid, elbow, calcaneus, navicular, ribs, and cervical spine transverse/spinous processes. 2, 3, 4

Site-Specific Advanced Imaging Recommendations

Hip and Pelvis Fractures

• MRI without contrast is the gold standard with 99-100% sensitivity for radiographically occult proximal femoral and pelvic fractures. 1
• Coronal STIR sequence alone achieves 100% sensitivity, with coronal T1 adding specificity and confidence. 1
• CT has variable sensitivity (69-87% in comparative studies) and misses a significant proportion of fractures that MRI detects, particularly nondisplaced fractures. 1
• For high-risk femoral neck fractures (lateral "tension-type"), immediate MRI is critical to prevent displacement, nonunion, and avascular necrosis. 1

Wrist and Scaphoid Fractures

• MRI without contrast or CT without contrast are both usually appropriate for suspected occult scaphoid fractures after negative radiographs. 1
• Additional radiographic views (carpal tunnel, semipronated oblique "scaphoid view") may reveal occult fractures before proceeding to advanced imaging. 1
• For hook of hamate fractures specifically, CT may be preferable to MRI. 1
• Most scaphoid fractures are missed due to failure to clinically examine for scaphoid tenderness (71% had no documented examination), not imaging limitations. 5

Stress Fractures (All Sites Excluding Vertebrae)

• MRI without contrast is the procedure of choice after negative radiographs, demonstrating stress abnormalities as early as bone scintigraphy but with considerably greater specificity. 1
• Fluid-sensitive sequences (STIR) and T1-weighted images are the favored screening sequences. 1
• Repeat radiographs at 10-14 days increase sensitivity to 30-70% and may be appropriate if immediate diagnosis is not required. 1
• For "need-to-know" immediate diagnosis scenarios, proceed directly to MRI. 1

Thoracolumbar Spine

• CT is the gold standard with 94-100% sensitivity for thoracolumbar fractures. 1
• Sagittal and coronal reformats from existing chest/abdomen/pelvis CT data are effective and radiation-sparing. 1
• MRI is indicated when spinal cord injury, cord compression, or ligamentous instability is suspected. 1

Alternative Modalities and Their Limitations

CT Without Contrast

• Advantages: Speed, utility in confused/agitated patients, excellent for cortical bone detail. 1
• Disadvantages: Lower sensitivity than MRI (69% vs 99% in one large study), poor soft-tissue evaluation (13% sensitivity for edema vs 99% for MRI), misses bone marrow edema patterns. 1
• Use when: MRI is contraindicated, unavailable, or for specific sites like hook of hamate. 1

Bone Scintigraphy

• Historically the reference standard but now superseded by MRI due to lower specificity (positive for bone contusions, arthritis, any osteoblastic process). 1
• May be reasonable alternative in claustrophobic patients. 1
• SPECT/CT increases specificity but still inferior to MRI overall. 1

Ultrasound

• Not appropriate for comprehensive fracture evaluation despite ability to detect periosteal changes, cortical irregularity, and soft-tissue edema. 1
• Cannot evaluate subcortical or trabecular bone. 1
• Sensitivity for hip fractures only 65% in available studies. 1

Clinical Decision Algorithm

1. Obtain appropriate initial radiographs with site-specific views (e.g., scaphoid series for wrist, AP pelvis for hip). 1

2. If radiographs are negative but clinical suspicion remains high:

   • High-risk fractures requiring immediate diagnosis (femoral neck, femoral head, anterior tibial diaphysis, navicular, fifth metatarsal base): Proceed directly to MRI without contrast. 1
   • Lower-risk fractures without urgent treatment implications: Consider repeat radiographs in 10-14 days OR proceed to MRI if earlier return-to-activity decision needed. 1
   • Hip/pelvis fractures in elderly: MRI without contrast is mandatory given near-perfect sensitivity and treatment implications. 1

3. If MRI is contraindicated or unavailable:

   • CT without contrast is the second-line option, accepting lower sensitivity. 1
   • For stress fractures, bone scintigraphy is an alternative but less specific. 1

Critical Pitfalls to Avoid

• Do not rely on clinical examination alone: Sensitivity is only 81% and specificity 68% for spine fractures; scaphoid fractures are frequently missed due to inadequate clinical assessment. 6, 5
• Do not add IV contrast for fracture detection: It provides no additional diagnostic value for identifying fractures on either CT or MRI. 1
• Do not use ultrasound as a primary modality for suspected occult fractures given poor sensitivity and inability to evaluate deep bone. 1
• Do not assume negative CT excludes fracture: Studies show CT misses 13-31% of fractures detected by MRI, particularly nondisplaced and trabecular fractures. 1
• For sacral fractures, always image the entire pelvis: Concomitant pelvic fractures occur frequently, and standard sacrum radiographs miss approximately 35% of sacral fractures. 6

Prognostic Value of MRI

• MRI grading of stress fracture severity (based on periosteal and marrow edema patterns) predicts return-to-play timing in athletes. 1
• Dynamic contrast-enhanced MRI can assess femoral head perfusion after hip fractures to predict osteonecrosis risk, though not routinely indicated for fracture detection alone. 1
• MRI accurately depicts fracture line extent, guiding conservative versus surgical management decisions for incomplete intertrochanteric fractures. 1