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Calculator · Does this ankle need an X-ray?
Ottawa ankle and foot rules
A rule-out tool, and one of the few that genuinely earns the description — sensitivity near 100% for clinically significant fractures. Any single positive means image; all negative means you can safely not.
What it asks
| Criterion | Points |
|---|---|
| Pain in the malleolar zone? The rules only apply if there is pain here or in the midfoot | No — 0 Yes — 0 |
| Bone tenderness — posterior edge or tip of the LATERAL malleolus Distal 6 cm | No — 0 Yes — 1 |
| Bone tenderness — posterior edge or tip of the MEDIAL malleolus Distal 6 cm | No — 0 Yes — 1 |
| Bone tenderness — base of the 5th metatarsal | No — 0 Yes — 1 |
| Bone tenderness — navicular | No — 0 Yes — 1 |
| Unable to weight-bear 4 steps, both immediately and now | No — 0 Yes — 1 |
How to read the score
| Score | Means | What to do |
|---|---|---|
| 0 | No X-ray indicated | All criteria negative. The rule is a rule-out and it is a good one — but it assumes an alert, cooperative patient you have actually palpated. |
| 1–5 | X-ray indicated | At least one positive. Ankle series if the tenderness is malleolar, foot series if it is the 5th metatarsal or navicular — and both if both. |
Before you use it
Not validated below 18 (some evidence down to 5, but it is not the same rule), and unreliable in intoxication, distracting injury, head injury, reduced sensation and pregnancy — all of which blunt the tenderness the rule depends on. Isolated distal fibular tenderness above 6 cm is outside the rule: think Maisonneuve, and examine the knee.
Source: Stiell et al, JAMA 1993; validated repeatedly since
Checked, and shown
Every threshold on this page was checked against its primary source by a practising doctor. Here is what that involved, and what it found.