Ottawa ankle rules

How it is done

For a patient with pain in the malleolar zone (around the ankle bones) after an acute ankle injury. An ankle X-ray is needed if ANY of these is present: (1) bone tenderness along the distal 6 cm of the posterior edge, or at the tip, of the lateral malleolus (fibula); (2) bone tenderness along the distal 6 cm of the posterior edge, or at the tip, of the medial malleolus (tibia); (3) unable to bear weight for four steps both immediately after the injury and at the time of assessment. If none is present, no X-ray is needed.

What the studies found

Decision rule for ankle X-ray — a rule-out tool. A negative rule makes an ankle fracture very unlikely; a positive rule means 'X-ray', not 'fracture' (LR+ about 1.6). Bachmann et al. 2003 (systematic review, 27 studies, 15,581 patients): pooled sensitivity 98% (95% CI 96.3–99.3%) and LR− 0.08 (95% CI 0.03–0.18) for the ankle. Specificity was not pooled; 39.8% is the median across studies (interquartile range 27.9–47.7%). Only 13 of the 27 pooled studies X-rayed every patient. Accuracy was lower when ankle and foot were assessed together (LR− 0.17). In children (ankle and midfoot together), LR− 0.07. A later meta-analysis (Barelds 2017) pooled LR− 0.12 for the ankle rules. The rules were derived by Stiell 1992 and refined and validated by Stiell 1993.

What the numbers mean

• Positive result: barely informative: a positive result changes little.
• Negative result: a strong rule-out: a negative result makes the diagnosis very unlikely.

The ladder: what a result does to your estimate

Calculated from the likelihood ratios above. For any other starting estimate, use the probability calculator.

Work out what a result means for your patient: probability calculator

Source

Bachmann LM, Kolb E, Koller MT, Steurer J, ter Riet G. Accuracy of Ottawa ankle rules to exclude fractures of the ankle and mid-foot: systematic review. BMJ. 2003;326(7386):417. Review summary (NCBI Bookshelf) · systematic review
Also cited: Stiell IG, Greenberg GH, McKnight RD, Nair RC, McDowell I, Worthington JR. A study to develop clinical decision rules for the use of radiography in acute ankle injuries. Ann Emerg Med. 1992;21(4):384–390. Journal article (DOI)
Also cited: 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):1127–1132. PubMed
Also cited: Barelds I, Krijnen WP, van de Leur JP, van der Schans CP, Goddard RJ. Diagnostic accuracy of clinical decision rules to exclude fractures in acute ankle injuries: systematic review and meta-analysis. J Emerg Med. 2017;53(3):353–368. Journal article (DOI)

Website-only page, added to the library on 9 October 2026. Rule It In, Rule It Out discusses this but has no separate test card for it. Figures independently checked against the sources cited above; any note above says where only the abstract could be checked.