Will a CT (computed tomography) scan without contrast show a hip fracture?

CT Without Contrast for Hip Fracture Detection

Yes, CT without contrast will show most hip fractures, with a sensitivity of 79-94%, but it can miss up to 21% of occult fractures, so MRI should follow if clinical suspicion persists despite negative CT. 1

Diagnostic Performance of Non-Contrast CT

Sensitivity and Specificity

• CT without IV contrast has a sensitivity of 79-94% and specificity approaching 100% for detecting hip fractures when radiographs are negative but clinical suspicion remains high 1, 2
• The American College of Radiology (ACR) 2024 guidelines support CT as the next imaging examination after negative radiographs when there is persistent clinical concern for hip fracture, given its relative speed compared to MRI 1
• A meta-analysis of 1,248 patients found 50 false-negative CT examinations, meaning CT missed fractures in approximately 10% of cases 1, 2

Clinical Impact

• CT after negative radiographs found occult hip fractures in 24.1% of patients and led to a change in management in 20% of cases 1
• Among patients with negative radiographs, 39% had surgical hip fractures that required detection 1

When CT is Most Useful

Primary Indications

• CT without contrast is the preferred next step after negative radiographs when MRI is unavailable or contraindicated (e.g., pacemakers, patient confusion, claustrophobia) 1
• CT excels at characterizing known fractures for surgical planning, including measuring impaction angles and posterior tilt that predict fracture stability 1, 3
• CT improved interobserver agreement for surgical decision-making and altered treatment plans in 21% of non-displaced femoral neck fractures 1, 3

Post-Reduction Evaluation

• CT is indicated after hip dislocation reduction to evaluate for intraarticular fragments, joint congruence, and acetabular fractures 1, 4
• CT has 87.3% sensitivity for detecting intraarticular fracture fragments, though 43.3% of patients with negative CT may still have small fragments at arthroscopy 1, 4

Critical Limitations and Pitfalls

False-Negative Rate

• The most important caveat: patients with persistent clinical concern for hip fracture after negative or equivocal CT still need MRI 1
• CT sensitivity (79-94%) is significantly lower than MRI sensitivity (99-100%) for occult fractures 1
• One study reported CT sensitivity as low as 86%, missing 14% of occult hip fractures 5

Timing Considerations

• CT can delay time to diagnosis and surgery, with mean delays of 2.0-3.2 days from initial radiograph to CT scan 6
• Rapid diagnosis is crucial because delays increase fracture-related morbidity and risk of complications like osteonecrosis 1

Algorithmic Approach

Step 1: Initial Imaging

• Start with AP pelvis radiograph plus cross-table lateral view of symptomatic hip 1, 3
• Approximately 90% of proximal femoral fractures are visible on initial radiographs 1, 3

Step 2: If Radiographs Negative but Clinical Suspicion High

• Order CT without IV contrast if MRI unavailable or contraindicated 1
• There is no evidence supporting CT with IV contrast for hip fracture evaluation 1

Step 3: If CT Negative but Clinical Suspicion Persists

• Proceed to MRI without IV contrast, which has near 100% sensitivity 1
• A negative MRI allows confident discharge and reduces unnecessary admissions 1

Step 4: If Fracture Confirmed on CT

• Use CT for surgical planning to measure impaction angles (>135 degrees predicts 11.73 times higher odds of secondary displacement) and assess fracture morphology 1, 3
• CT improves classification reliability and surgical decision-making compared to radiographs alone 1, 3

Contrast Administration

• Never use IV contrast for hip fracture evaluation—there is no evidence supporting its use and it adds cost and risk without diagnostic benefit 1, 7
• Non-contrast CT provides all necessary information for fracture detection and characterization 1, 3