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    Ottawa Ankle Rule

    Rules out clinically significant foot and ankle fractures to reduce use of x-ray imaging.
    When to Use
    Why Use

    Patients ≥2 years old with ankle or midfoot pain/tenderness in the setting of trauma.

    The Ottawa Ankle Rule was derived to aid efficient use of radiography in acute ankle and midfoot injuries.

    • Rules have been prospectively validated on multiple occasions in different populations and in both children and adults.
    • Sensitivities range from the high 90-100% range for “clinically significant” ankle and midfoot fractures, defined as fracture or avulsion >3 mm.
    • Specificities are approximately 41% for the ankle and 79% for the foot, though the rule is not designed or intended for specific diagnosis.
    • The Ottawa Ankle Rule is useful for ruling out fracture (high sensitivity), but poor for ruling in fractures (many false positives).

    Tips from the creators at University of Ottawa:

    • Palpate the entire distal 6 cm of the fibula and tibia.
    • Do not neglect the importance of medial malleolar tenderness.
    • “Bearing weight” counts even if the patient limps.
    • Use with caution in patients under age 18.

    Precautions from the creators at University of Ottawa:

    • Clinical judgment should prevail if examination is unreliable for any of the following reasons:
      • Intoxication.
      • Uncooperative patient.
      • Distracting painful injuries.
      • Diminished sensation in legs.
      • Gross swelling which prevents palpation of malleolar tenderness.
    • Always provide written instructions.
    • Encourage follow-up in 5-7 days if pain and ability to walk are not better.
    • Patients without criteria for imaging by the Ottawa Ankle Rule are highly unlikely to have a clinically significant fracture and do not need plain radiographs.
    • Application of the Ottawa Ankle Rule can reduce the number of unnecessary radiographs by as much as 25-30%, improving patient flow in the ED.


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    Creator Insights
    Dr. Ian Stiell

    From the Creator

    Why did you develop the Ottawa Ankle Rule? Was there a clinical experience that inspired you to create this rule for clinicians?

    We found that emergency doctors were ordering many imaging studies for ankle injuries that were then found to be normal. I thought if there were a set a rules with criteria developed by emergency physicians, for emergency physicians, they would help this problem and shorten emergency department wait times and costs.

    What pearls, pitfalls and/or tips do you have for users of the Ottawa Ankle Rule? Are there cases when it has been applied, interpreted, or used inappropriately?

    As a general rule in the emergency department, x-rays are rarely useful because most injuries are soft tissue, and an x-ray does not show ligament injury.

    What recommendations do you have for health care providers once they have applied the Ottawa Ankle Rule besides imaging, or when imaging is negative?

    If the rule states imaging is required, rarely does a patient need both an ankle and foot x-ray, just one or the other or neither. If negative, most patients will heal quickly from a soft tissue ankle injury, but some may require physical therapy.

    What are some situations in which you see clinicians interpreting the rule improperly or incorrectly leading to inappropriate x-ray utilization?

    Sometimes doctors don't properly assess the patient's ability to bear weight on their injured ankle. Most patients can and will walk, but it may take a little encouragement from the physician.

    About the Creator

    Ian Stiell, MD, MSc, FRCPC, is Professor and Chair, Department of Emergency Medicine, University of Ottawa; Distinguished Professor and University Health Research Chair, University of Ottawa; Senior Scientist, Ottawa Hospital Research Institute; and Emergency Physician, The Ottawa Hospital. He is internationally recognized for his research in emergency medicine with a focus on the development of clinical decision rules and the conduct of clinical trials involving acutely ill and injured patients treated by prehospital services and in emergency departments. He is best known for the development of the Ottawa Ankle Rule, the Canadian C-Spine Rule, and Canadian CT Head Rule and as the Principal Investigator for the landmark OPALS Studies for prehospital care. Dr. Stiell is the Principal Investigator for 1 of 3 Canadian sites in the Resuscitation Outcomes Consortium (ROC) which is funded by CIHR, NIH, HSFC, AHA, and National Defence Canada. Dr. Stiell is a Member of the Institute of Medicine of the U.S. National Academies of Science.

    To read more about Dr. Stiell's work, visit his website.

    To view Dr. Ian Stiell's publications, visit PubMed

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