Ottawa Ankle Rules Calculator
The Ottawa Ankle Rules decide whether an X-ray is needed after an acute ankle or midfoot injury. An ankle X-ray is indicated for malleolar-zone pain with bone tenderness at either malleolus or an inability to bear weight; a foot X-ray for midfoot-zone pain with tenderness at the fifth-metatarsal base or navicular, or an inability to bear weight.
Quick answer
The Ottawa Ankle Rules say an ankle X-ray is needed for pain in the malleolar zone with bone tenderness at the posterior edge or tip of either malleolus, or an inability to bear weight for four steps both immediately and at assessment. A foot X-ray is needed for midfoot-zone pain with tenderness at the fifth-metatarsal base or navicular, or the same inability to bear weight.
Ankle (malleolar) zone
Foot (midfoot) zone
Weight-bearing
No ankle or foot X-ray indicated by the Ottawa rules
By the Ottawa Ankle Rules: no ankle or foot x-ray indicated by the ottawa rules.
The rules are highly sensitive for clinically significant fractures and are used to safely reduce unnecessary radiographs. They are applied with caution in young children, intoxicated or distracted patients, and those with reduced sensation. A clinician confirms.
How to use the Ottawa Ankle calculator
- 1Mark the zones of pain. Tick whether there is pain in the malleolar zone and/or the midfoot zone.
- 2Mark the tenderness and weight-bearing findings. Tick tenderness at the lateral malleolus, medial malleolus, fifth-metatarsal base or navicular, and whether the patient cannot bear weight for four steps both immediately and at assessment.
- 3Read whether X-rays are indicated. The tool reports whether an ankle X-ray, a foot X-ray, both, or neither are indicated by the rules β to confirm with a clinician.
Medical disclaimer: This is general health information, not medical advice. It does not diagnose or treat any condition, and the results are estimates based on public reference formulas. Always consult a qualified doctor about your individual health. If you think you may have a medical emergency, contact your local emergency services immediately.
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Book a consultationFrequently asked questions
What are the Ottawa Ankle Rules used for?β
They are a validated decision rule that helps decide whether an X-ray is needed after an acute ankle or midfoot injury, safely reducing unnecessary radiographs. They are highly sensitive for clinically significant fractures.
What counts as "unable to bear weight"?β
In the rule, inability to bear weight means the patient cannot take four steps (two on each leg) both immediately after the injury and at the time of assessment, regardless of limping. Being able to limp four steps counts as able to bear weight.
Do the Ottawa Ankle Rules apply to everyone?β
They were validated in adults and are widely applied, but they are used with caution in young children, intoxicated or distracted patients, those with reduced sensation, or after a delayed presentation. A clinician decides whether the rule applies.
Is my data stored?β
No. The calculator runs entirely in your browser; nothing you enter is sent to a server.
Sources & validation
This calculator reproduces the published Ottawa Ankle score, validated for whether an ankle or foot X-ray is needed after acute injury.
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