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    Ottawa Ankle Rule

    Shows areas of tenderness to be evaluated in ankle trauma patients to determine need for imaging.
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    When to Use
    Pearls/Pitfalls
    Why Use

    The Ottawa ankle rule should be applied to all patients aged 2 and older with ankle or midfoot pain/tenderness in the setting of trauma.

    The Ottawa ankle rules were derived to aid in the 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 for the Ottawa ankle rule range from the high 90%-100% range for “clinically significant” ankle and midfoot fractures. This is defined as a fracture or an avulsion greater than 3 mm.
    • Specificities for the Ottawa ankle rules are approximately 41% for the ankle and 79% for the foot, though the rule is not designed/intended for specific diagnosis.
    • The Ottawa ankle rules are useful in 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 6cm of the fibula and tibia;
    • Do not neglect the importance of medial malleolar tenderness;
    • “Bearing weight” counts even if the patient limps;
    • Be caution in patients under age 18.

    Precautions from the creators at University of Ottawa:

    • Clinical judgment should prevail if examination is unreliable:
      • 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 is not better

    Patients without criteria for imaging by the Ottawa ankle rules are highly unlikely to have a clinically significant fracture and do not need plain radiographs.

    Application of the Ottawa ankle rules can reduce the number of unnecessary radiographs by as much as 25-30%, improving patient flow in the ED.

    ottawa ankle rule
    ottawa ankle rule
    About the Creator
    Dr. Ian Stiell
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    Next Steps
    Evidence
    Creator Insights

    Advice

    • If ankle pain is present and there is tenderness over the posterior 6 cm or tip of the posterior or lateral malleolus, then an ankle-ray is indicated.
    • If midfoot pain is present and there is tenderness over the navicular or the base of the fifth metatarsal, then a foot-xray is present.
    • 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.

    Management

    • 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 criteria do not need an ankle or foot x-ray. Those that fulfill 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 judgement.

    Facts & Figures

    • An ankle x-ray series is only required if there is pain in the malleolar zone AND any of these findings:
      • Bone tenderness at A (posterior edge or tip of lateral malleolus), OR
      • Bone tenderness at B (posterior edge or top of medial malleolus), OR
      • Inability to bear weight both immediately after injury and in ED.
    • A foot x-ray series is only required if there is pain in the midfoot zone AND any of these findings:
      • Bone tenderness at C (base of 5th metatarsal), OR
      • Bone tenderness at D (navicular), OR
      • Inability to bear weight both immediately after injury and in ED.

    Evidence Appraisal

    Original derivation study in 1992

    • Included non-pregnant patients over age 18 who presented to Ottawa Civic and General Hospitals with a new injury < 10 days old.
    • Initial pilot study with 155 patients while full-scale study included 750 patients.
    • Clinically significant fracture = any fracture that was not an avulsion of 3 mm or less across
    • Initial rules: Age 55 years or greater, inability to bear weight immediately after the injury and for four steps in the emergency department, or bone tenderness at the posterior edge or tip of either malleolus for the ankle. For the foot, criteria included pain in the midfoot and bone tenderness at the navicular bone, cuboid, or the base of the fifth metatarsal.

    Further validation and refinement in 1993

    • Prospective study of 1032 patients in the validation and refinement phase of the study with 121 clinically significant fractures.
    • Sensitivity of 100% for significant malleolar zone fractures and 98% for significant midfoot fractures.
    • Rules further refined by removing age cut-off from ankle rule and cuboid tenderness from foot rule, but also added weightbearing criteria to foot rule.
    • Sensitivity of refined rule for both foot and ankle fractures was 100%, but increased ankle specificity to 41% and foot specificity to 79%.
    • An additional 453 patients were then prospectively enrolled in the second phase of the study, where they validated their refined rules, yielding a sensitivity of 100% for both ankle and midfoot fractures.

    Ottawa ankle rules (OAR) in children.

    • A study of 670 children age 2 to 16 at two separate sites found that the OAR again had a sensitivity of 100% for both clinically significant ankle and midfoot fractures.
    • Study also found that ankle x-rays could be reduced by 16% and foot x-rays by 29% if the rules were in use at the time of the study.
    • Subsequent meta-analysis of the OAR in children found 12 studies with 3,130 patients and 671 fractures, with a pooled sensitivity of 98.5% and