Ottawa Ankle Rule
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:
- 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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- 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.
- RICE plan (Rest, Ice, Compression, Elevation).
- Splinting/crutches and pain medication, pending outcome.
- 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.