Ottawa Ankle Rules
- Fysiobasen
- Oct 4
- 3 min read
The Ottawa Ankle Rules (OAR) are a set of clinical decision-making guidelines developed to determine the need for radiographic imaging in acute ankle injuries. Their main purpose is to reduce unnecessary X-rays while maintaining high diagnostic accuracy for detecting fractures.
Ankle sprains are among the most common musculoskeletal injuries. In the U.S., it is estimated that 25,000 ankle sprains occur daily, equating to one sprain per 10,000 people per day¹. A meta-analysis by Doherty et al. (2014) found higher rates of ankle sprains in:
Women vs. men: 13.6 vs. 6.94 per 1000 exposures.
Children vs. adolescents: 2.85 vs. 1.94 per 1000 exposures.
Adolescents vs. adults: 1.94 vs. 0.72 per 1000 exposures¹.
When to Order Radiographs
Ankle X-ray if pain is present in the malleolar zone and any of the following:
Bone tenderness along the distal 6 cm of the posterior tibia or at the tip of the medial malleolus.
Bone tenderness along the distal 6 cm of the posterior fibula or at the tip of the lateral malleolus.
Inability to bear weight immediately after the injury and for four steps during initial evaluation.
Foot X-ray if pain is present in the midfoot zone and any of the following:
Bone tenderness at the base of the 5th metatarsal.
Bone tenderness at the navicular bone.
Inability to bear weight immediately after the injury and for four steps during initial evaluation⁶.
Special Considerations
Excluded groups: pregnant women and patients with impaired ability to follow instructions (e.g., head injury, intoxication).
Children: OAR can be used safely in children over 6 years with sensitivity of 98.5%, though evidence in younger children is limited⁷.
Evidence and Accuracy
High sensitivity: Nearly 100% for ruling out ankle and midfoot fractures.
Moderate specificity: Leads to some false positives, but minimizes missed fractures.
Reduction in imaging: OAR reduces unnecessary radiographs by 30–40%.
Systematic review findings:
Sensitivity = 97.6%
Median specificity = 31.5%
Probability of fracture after negative OAR < 1.4%⁸.
Reliability:
Sensitivity for malleolar fractures = 1.0 (95% CI 0.95–1.0).
Sensitivity for midfoot fractures = 1.0 (95% CI 0.82–1.0)⁹.
Validation in pediatrics:
Children aged 2–16 years: sensitivity = 1.0 for both malleolar and midfoot fractures¹⁰.
Clinical Significance
Reduced imaging: Use of OAR has been shown to decrease ankle radiographs by 28% and foot radiographs by 14% in hospital settings⁹.
Cost savings: Lower healthcare costs by reducing unnecessary imaging and associated consultations (p < .001)⁹.
Conclusion
The Ottawa Ankle Rules provide an evidence-based, efficient, and safe method to determine when radiographs are indicated in acute ankle injuries. With near-perfect sensitivity and strong clinical validation, OAR serve as an essential screening tool in emergency and sports medicine. However, due to moderate specificity, clinical judgment and additional tests may still be required in ambiguous cases.
References
Doherty, C., Delahunt, E., Caulfield, B., Hertel, J., Ryan, J. and Bleakley, C., 2014. The incidence and prevalence of ankle sprain injury: a systematic review and meta-analysis of prospective epidemiological studies. Sports medicine, 44(1), pp.123-140.
Brooks SC, Potter BT, Rainey JB. Inversion injuries of the ankle: clinical assessment and radiographic review. BMJ 1981; 282: 607-608
Stiell IG, Greenberg GH, McKnight RD, Nair RC, McDowell I, Reardon M, Stewart JP, Maloney J. Decision rules for the use of radiography in acute ankle injuries. JAMA 1993;269:1127-32.
Kerkhoffs, G.M., van den Bekerom, M., Elders, L.A., van Beek, P.A., Hullegie, W.A., Bloemers, G.M., de Heus, E.M., Loogman, M.C., Rosenbrand, K.C., Kuipers, T. and Hoogstraten, J.W.A.P., 2012. Diagnosis, treatment and prevention of ankle sprains: an evidence-based clinical guideline. British journal of sports medicine, 46(12), pp.854-860.
Stiell IG, McKnight RD, Greenberg GH, McDowell I, Nair RC, Wells GA, Johns C, Worthington JR. Implementation of the Ottawa Ankle Rules. JAMA 1994;271:827-32. [1]
Dowling S, Spooner CH, Liang Y, et al. (April 2009). "Accuracy of Ottawa Ankle Rules to exclude fractures of the ankle and midfoot in children: a meta-analysis". Acad Emerg Med. 16 (4): 277–87
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;326:417-23.
Stiell IG, McKnight RD, Greenberg GH, McDowell I, Nair RC, Wells GA, et al. Implementation of the Ottawa ankle rules. JAMA 1994; 271: 827-832
Plint AC, Bulloch B, Osmond MH, et al. Validation of the Ottawa Ankle Rules in children with ankle injuries. Acad Emerg Med. 1999 Oct;6(10):1005-9
