Ottawa ankle rules: radiographs indicated in acute ankle injury when?

• A. Radiographs if tenderness at the posterior edge/tip of either malleolus or inability to bear weight both immediately and in the ED.
• B. Radiographs only if swelling.
• C. Radiographs always for ankle pain.
• D. Radiographs never.

Answer: (A)

The test is about applying the Ottawa ankle rules, which guide when to obtain radiographs after an acute ankle injury. The essential point is that X-rays are not routine for every ankle pain; they’re indicated only when clinical features suggest a fracture risk.

Two key criteria trigger imaging: tenderness at the posterior edge or tip of either malleolus, and the inability to bear weight both immediately after the injury and in the ED (typically meaning the patient cannot take four steps). If any of these signs are present, a fracture cannot be ruled out confidently from a simple exam, so radiographs are warranted. If none are present, the likelihood of fracture is low enough that radiographs can be avoided, reducing unnecessary radiation and healthcare costs. The rule’s strength lies in its high sensitivity—few fractures are missed when these criteria are followed.

Swelling alone doesn’t mandate imaging, and imaging every time or never imaging would not align with the evidence-based approach. The correct statement reflects the targeted criteria that identify patients at meaningful risk for fracture while sparing those with low risk from unnecessary radiographs.