How to rule out hip fracture after a fall in an elderly patient?

Ruling Out Hip Fracture After Fall in Elderly Patients

When an elderly patient presents with hip pain after a fall, MRI should be obtained if initial radiographs are negative but clinical suspicion for fracture remains high. 1

Initial Evaluation

Clinical Assessment

• Look for specific signs that suggest hip fracture:
  • Inability to bear weight on the affected limb
  • Pain in the groin, buttock, knee, thigh, or back
  • External rotation and shortening of the affected limb
  • Tenderness over the greater trochanter or with hip rotation 2, 3

Risk Factors to Consider

• Age over 65 years
• Osteoporosis
• Previous fractures
• Polypharmacy
• Visual impairment
• Neurological disorders
• Side-impact falls (highest risk for hip fracture) 4, 5

Diagnostic Algorithm

Step 1: Initial Imaging

• Radiographs are the first-line imaging modality 1
  • Standard views: Anteroposterior (AP) pelvis and cross-table lateral view of the affected hip
  • AP view should be taken with approximately 15° internal rotation

Step 2: If Radiographs Are Negative But Clinical Suspicion Remains

• Proceed directly to MRI - this is the preferred advanced imaging modality 1
  • MRI has the highest sensitivity for detecting occult hip fractures
  • As demonstrated in the AAOS guideline case study, MRI can detect fractures not visible on plain radiographs 1

Step 3: If MRI Is Unavailable

• CT scan can be considered as an alternative
• Bone scan may be used if both MRI and CT are unavailable, but has limitations:
  • Lower sensitivity in the first 24-72 hours after injury
  • Less anatomic detail than MRI or CT

Important Clinical Considerations

Urgency of Diagnosis

• Delayed diagnosis of hip fracture increases:
  • Mortality
  • Morbidity
  • Length of hospital stay
  • Medical costs 1

High Index of Suspicion

• Even when patients can walk and have no documented trauma, localized hip pain, or typical deformity, maintain suspicion for hip fracture 2
• Remember that approximately 1% of falls in the elderly result in hip fracture, but these account for significant disability, death, and medical costs 4

Common Pitfalls to Avoid

1. Relying solely on physical examination - hip fractures cannot be reliably diagnosed or excluded on physical examination alone 1
2. Failing to obtain advanced imaging when radiographs are negative - up to 10% of hip fractures may not be visible on initial radiographs
3. Discharging patients who can bear weight - some patients with hip fractures can still walk and present with vague symptoms 2
4. Delaying diagnosis - delays increase mortality and morbidity 1

Post-Diagnosis Management

• If fracture is confirmed, prompt orthogeriatric comanagement is recommended 1
• Surgery should be performed within 48 hours of injury 1
• Appropriate rehabilitation program should be implemented early 1, 6

By following this systematic approach to ruling out hip fracture in elderly patients after a fall, clinicians can ensure timely diagnosis and treatment, ultimately improving patient outcomes and reducing mortality and morbidity.