Ottawa Ankle Rule
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:
- 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.