In an 82-year-old woman with hypertension and epilepsy (on phenytoin and losartan) who fell onto her right side and now has right hip pain with normal plain radiographs, which imaging study should be obtained now in addition to pain management?

CT Hip Without IV Contrast Should Be Ordered Now

In this 82-year-old woman with persistent hip pain after a fall and negative plain radiographs, CT of the hip without IV contrast is the appropriate next imaging study. 1

Clinical Reasoning

This patient has a classic presentation for occult hip fracture:

• Age 82 with osteopenia (high-risk population)
• Mechanical fall onto the right side
• Persistent pain limiting ambulation despite walker use
• Pain with internal rotation of the hip
• Normal plain radiographs

The 2025 ACR Appropriateness Criteria explicitly state that CT without IV contrast is the next imaging examination after negative radiographs when there is persistent clinical concern for hip fracture. 1

Why CT Is the Right Choice

Speed and Availability

CT is faster to obtain than MRI, which is critical because:

• Delayed diagnosis increases morbidity from prolonged immobility
• Risk of osteonecrosis increases with delayed treatment
• Early surgical intervention improves outcomes 1

Diagnostic Performance

Recent meta-analyses demonstrate:

• CT sensitivity of 94% and specificity of 100% for occult hip fractures 1
• CT detects occult fractures in 24.1% of patients with negative radiographs 1
• CT changes management in 20% of cases 1

Clinical Impact

In patients with negative radiographs but persistent clinical suspicion, 39% have surgical hip fractures that require operative management 1

Important Caveats

If the CT is negative or equivocal but clinical suspicion remains high, MRI will still be needed. 1 However, CT should be performed first due to its speed, availability, and excellent diagnostic performance.

What NOT to Order

• MRI without contrast: Not first-line despite higher sensitivity; reserve for negative/equivocal CT 1
• Bone scan: Insufficient evidence to support its use 1
• CT with IV contrast: No evidence to support this 1
• Ultrasound: Insufficient evidence for acute traumatic hip pain 1

Additional Considerations for This Patient

Phenytoin and Fracture Risk

This patient is on phenytoin, which increases fracture risk through:

• Vitamin D metabolism acceleration leading to osteomalacia
• Increased risk of osteoporosis and bone fractures 2

This makes occult fracture even more likely in this clinical scenario.

Management Priorities

While awaiting imaging:

1. Aggressive pain management
2. Maintain non-weight bearing status on the affected side
3. Avoid hip manipulation that could displace an occult fracture
4. Expedite CT scheduling (ideally within hours, not days)

The key principle: In elderly patients with fall-related hip pain and negative radiographs who cannot ambulate normally, assume occult fracture until proven otherwise. The clinical examination findings (pain with internal rotation, inability to walk despite walker) strongly suggest intra-articular pathology that warrants immediate cross-sectional imaging 1.