When should a patient with a rolled ankle and possible risk factors such as osteoporosis or previous fractures be referred for an x-ray?

When to Refer for X-Ray After Rolling an Ankle

Apply the Ottawa Ankle Rules to determine if x-ray is needed: order ankle radiographs if the patient cannot bear weight immediately after injury, cannot take 4 steps in the emergency department, or has point tenderness over the posterior edge or tip of either malleolus, the navicular bone, or the base of the fifth metatarsal. 1, 2

Ottawa Ankle Rules Criteria

The decision to obtain x-rays should be based on these specific clinical findings:

• Inability to bear weight both immediately after the injury AND in the emergency department (unable to take 4 steps) 1, 3
• Point tenderness over the posterior edge or inferior tip of the lateral malleolus 1
• Point tenderness over the posterior edge or inferior tip of the medial malleolus 1
• Point tenderness over the navicular bone 1
• Point tenderness over the base of the fifth metatarsal 1

If ANY of these criteria are positive, obtain three-view ankle radiographs (anteroposterior, lateral, and mortise views). 1

Sensitivity and Safety of the Ottawa Ankle Rules

The Ottawa Ankle Rules have a sensitivity of 92-99% for detecting ankle fractures, meaning they correctly identify nearly all fractures while safely avoiding unnecessary x-rays in patients without these findings. 1, 3, 4

If the patient does NOT meet any Ottawa Ankle Rules criteria, x-rays are not routinely indicated. 1

Special Populations and Exclusion Criteria

When Ottawa Ankle Rules DO NOT Apply:

The rules are validated for adults and children ≥5 years of age, but should NOT be used in patients with: 1

• Peripheral neuropathy (including diabetic neuropathy) - these patients may have no pain despite fracture and require x-rays regardless of examination findings 1
• Neurological compromise of the lower extremity 1
• Intoxication that prevents reliable examination 1
• Distracting painful injuries elsewhere 1
• Children under 5 years of age 1

For patients with osteoporosis or previous fractures who are neurologically intact, the standard Ottawa Ankle Rules still apply - these conditions alone do not mandate x-rays if the rules are negative. 1

If Initial X-Rays Are Negative But Pain Persists

Order MRI without IV contrast if pain persists beyond 3 weeks despite appropriate immobilization, as up to 15% of fractures may not be visible on initial radiographs. 5, 3

MRI is superior to CT for detecting occult fractures, stress fractures, osteochondral injuries, and ligamentous damage that may not appear on standard radiographs. 1, 5, 3

Common Pitfalls to Avoid

• Do not order x-rays based solely on inability to bear weight if this is the ONLY positive finding - consider reassessing the patient in several days if symptoms persist, as this approach can prevent unnecessary radiation exposure. 4
• Do not rely on clinical examination alone in the first 48 hours - excessive swelling and pain limit accurate assessment of ligament integrity. 2, 3
• Do not miss high ankle (syndesmotic) sprains - test with the crossed-leg maneuver, as these require different management and longer recovery. 2, 3
• Weight-bearing radiographs should be obtained when possible to assess fracture stability, particularly for malleolar fractures where a medial clear space <4 mm confirms stability. 1