Ottawa ankle rules
Need for ankle or foot radiographs after acute ankle injury in adults
Sources last checked: 2026-10-13
Ottawa ankle rules
Need for ankle or foot radiographs after acute ankle injury in adults
Palpate the posterior edge of the distal 6 cm of each malleolus, not just the tip. 'Unable to bear weight' means unable to take four steps (limping counts as bearing weight). The rule rules out fractures; it does not grade ligament injury.
Interpretation
| Rule not applicable | The patient is outside the population the rule was derived in, so the rule makes no statement about imaging for this patient. |
|---|---|
| No radiograph required by the rule | In the 1993 validation the probability of a fracture with a negative rule was 0 % (95 % CI 0–0.8 % ankle, 0–0.4 % foot). The rule addresses fracture at presentation only. |
| Ankle radiograph series indicated by the rule | Malleolar-zone pain with malleolar bone tenderness or inability to bear weight. |
| Foot radiograph series indicated by the rule | Midfoot-zone pain with tenderness at the fifth metatarsal base or navicular, or inability to bear weight. |
| Ankle and foot radiograph series indicated by the rule | Both the ankle and the foot rule are positive. |
What is the Ottawa ankle rules?
The Ottawa ankle rules decide which adults with acute ankle injuries need ankle or foot radiographs. Stiell and colleagues derived them in Ottawa and refined and validated them in 1993 (JAMA), with 100 % sensitivity for malleolar and midfoot fractures. Applying them can reduce ankle radiography by about a third.
When to use it
- Adults with an acute inversion or twisting ankle injury in the emergency department or primary care.
- Deciding between ankle series, foot series, both or no imaging.
When not to use it
- Patients who cannot be examined reliably — intoxication, altered sensation, head injury.
- Children, unless a paediatric validation is used locally.
How it is calculated
Ankle series if malleolar-zone pain AND (tenderness posterior edge/tip of lateral malleolus OR of medial malleolus [distal 6 cm] OR unable to bear weight immediately and in ED). Foot series if midfoot-zone pain AND (tenderness at base of 5th metatarsal OR navicular OR unable to bear weight immediately and in ED).
Clinical pearls and limitations
- Palpate the posterior edge of the distal 6 cm of each malleolus, not just the tip. 'Unable to bear weight' means unable to take four steps (limping counts as bearing weight). The rule rules out fractures; it does not grade ligament injury.
- Palpate the posterior edge of the distal 6 cm of both malleoli, not just the tips.
- Weight-bearing means four steps, limping allowed, both immediately after injury and in the ED.
- Pain in the midfoot zone with tenderness at the base of the fifth metatarsal is the classic Jones/avulsion fracture setting.
- A negative rule does not exclude ligament injury.
Frequently asked questions
When is an ankle X-ray needed according to the Ottawa rules?
With malleolar-zone pain plus tenderness at the posterior edge or tip of either malleolus, or inability to bear weight both immediately and in the ED.
How reliable are the Ottawa ankle rules?
Sensitivity was 100 % in the 1993 validation; systematic reviews confirm sensitivity close to 100 %.
Do the Ottawa ankle rules apply to the foot?
Yes, a separate foot rule covers midfoot pain with tenderness at the fifth metatarsal base or navicular, or inability to bear weight.
Evidence and guidelines
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