What is the best next step in diagnosing hip pain in an 82-year-old woman with osteopenia and limited range of motion after a mechanical fall, with initial radiography (x-ray) showing no evidence of fracture or dislocation?

Best Next Step in Diagnostic Evaluation of Hip Pain After a Fall with Negative Radiographs

CT scan of the right hip is the best next diagnostic step for this 82-year-old woman with hip pain and limited range of motion after a mechanical fall with negative initial radiographs but clinical suspicion for fracture. 1

Rationale for CT Scan

• Multiple studies over the past two decades have demonstrated the importance of cross-sectional imaging in revealing radiographically occult hip fractures in patients with acute traumatic hip pain 1
• Given the importance of rapid diagnosis in decreasing fracture-related morbidity, the relative speed in obtaining CT (versus MRI or bone scan) supports CT as the next imaging examination after negative radiographs when there is persistent clinical concern for hip fracture 1
• A recent meta-analysis demonstrated that CT after negative radiographs found occult hip fractures in 24.1% of cases and led to a change in management in 20% of cases 1

Diagnostic Algorithm for Hip Pain After Fall with Negative X-rays

1. First-line imaging: Standard radiographs (already completed, negative)
2. Second-line imaging: CT scan without contrast of the affected hip
3. Third-line imaging (if needed): MRI without contrast if CT is negative or equivocal but clinical suspicion remains high

Comparison of Diagnostic Options

Option	Appropriateness	Advantages	Disadvantages
CT scan	Recommended [1]	- Rapid availability - High specificity (100%) - Good sensitivity (79-94%) - Detects occult fractures	- Lower sensitivity than MRI
MRI	Alternative if CT unavailable [2]	- Highest sensitivity - Detects soft tissue injuries	- Limited availability - Time-consuming - Contraindications in some patients
Bone scan	Insufficient evidence [1]	- High sensitivity (87%)	- Delay in diagnosis (24-72 hours) - Lower specificity
Repeat X-ray in 1-2 weeks	Not recommended	- Low cost	- Significant delay in diagnosis - Risk of fracture displacement
DXA scan	Not recommended	- Diagnoses osteoporosis	- Not useful for acute fracture detection

Important Clinical Considerations

• In elderly patients with osteopenia and hip pain after a fall, occult fractures are common even with negative initial radiographs
• Delayed diagnosis of hip fractures increases morbidity, mortality, and reduces quality of life 1
• A study of elderly patients with hip or pelvic pain after low energy trauma found that 32% had fractures diagnosed on advanced imaging despite negative initial radiographs 3
• While the American College of Radiology gives MRI without contrast the highest appropriateness rating (9/9) for detecting occult fractures 2, CT is often more readily available and has been shown to be effective in this clinical scenario

Pitfalls to Avoid

• Do not delay advanced imaging in elderly patients with persistent hip pain after a fall, even with negative radiographs
• Do not rely solely on plain radiographs to rule out fracture in elderly patients with limited mobility after a fall
• CT may miss some occult fractures that would be detected on MRI, so if clinical suspicion remains high after a negative CT, consider MRI 1
• Patients with persistent clinical concern for hip fracture after a negative or equivocal CT will still need an MRI 1