Calculators · Emergency Medicine · Criteria
Ottawa ankle rules
Also called Ottawa ankle and foot rules, OAR
Which adults with acute ankle injury need an ankle or foot X-ray series.
Ankle X-ray series
Not required
- Foot X-ray series
- Not required
Neither series is indicated. The refined rules were 100% sensitive for malleolar and midfoot fractures in the 1993 validation.
Formula and scoring
Ankle series if malleolar-zone pain AND (lateral or medial malleolar tenderness, or inability to bear weight). Foot series if midfoot pain AND (5th metatarsal base or navicular tenderness, or inability to bear weight).
Exam and ward pearls
- Palpate the posterior edge of the distal 6 cm of each malleolus, not just the tip.
- The rules cut ankle radiographs by about one third.
When not to rely on it
- Derived and validated in adults; use with care in children, intoxicated patients and those with reduced sensation.
Source
- Stiell IG, Greenberg GH, McKnight RD, et al. Decision rules for the use of radiography in acute ankle injuries. Refinement and prospective validation. JAMA. 1993;269(9):1127-32. doi:10.1001/jama.269.9.1127 · PMID 8433468
- Bessen T, Clark R, Shakib S, Hughes G. A multifaceted strategy for implementation of the Ottawa ankle rules in two emergency departments. BMJ. 2009;339:b3056. (Box 1 reproduces the rules.) doi:10.1136/bmj.b3056 · PMID 19675080
Formula and cut-offs checked against these sources on 8 Nov 2026. Educational tool for clinicians; it does not replace clinical judgement.