This is an unprecedented time. It is the dedication of healthcare workers that will lead us through this crisis. Thank you for everything you do.

      Calc Function

    • Calcs that help predict probability of a diseaseDiagnosis
    • Subcategory of 'Diagnosis' designed to be very sensitiveRule Out
    • Disease is diagnosed: prognosticate to guide treatmentPrognosis
    • Numerical inputs and outputsFormula
    • Med treatment and moreTreatment
    • Suggested protocolsAlgorithm





    Chief Complaint


    Organ System


    Patent Pending

    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.


    Please fill out required fields.

    Next Steps
    Creator Insights


    • If ankle pain is present and there is tenderness over the posterior 6 cm or tip of the lateral or medial malleolus, then ankle x-ray is indicated.
    • If midfoot pain is present and there is tenderness over the navicular or the base of the fifth metatarsal, then foot x-ray is indicated.
    • If there is ankle or midfoot pain and the patient is unable to take four steps both immediately and in the emergency department, then x-ray of the painful area is indicated.


    • X-ray.
    • RICE plan (Rest, Ice, Compression, Elevation).
    • Splinting/crutches and pain medication, pending outcome.

    Critical Actions

    • Patients who fulfill none of the Ottawa Ankle Rule criteria do not need an ankle or foot x-ray. Those fulfilling either the foot or ankle criteria need an x-ray of the respective body part.
    • Many experts would consider this score “one directional.” Because the rule is sensitive and not specific, it provides a clear guide of which patients not to x-ray if all criteria are met. However, if a patient fails the criteria, need for x-ray can be left to clinical judgment.
    Content Contributors
    About the Creator
    Dr. Ian Stiell
    Are you Dr. Ian Stiell?
    Partner Content
    Content Contributors