Ottawa Ankle Rules

The Ottawa Ankle Rule aids in the judicious use of radiography in acute and midfoot injuries. Indicated in patients ≥ 2 years with ankle or midfoot pain or tenderness in the setting of trauma but ought to use caution in ages < 18 years. Implementation of the Ottawa Ankle Rule may reduce unnecessary radiographs and radiation exposure while improving patient flow. Additionally, patients without criteria for imaging are unlikely to have a clinically significant fracture.

Using the Ottawa Ankle Rule can reduce the number of unnecessary radiographs, limit radiation exposure, and improve patient flow.

Notes

• Ottawa Rules are good at ruling out fracture (high sensitivity) but poor for ruling in fractures (many false positives).
  • High Sensitivity (90-100%) for ruling out clinically significant ankle and midfoot fractures (fracture/avulsion > 3 mm)
  • Lower Specificity (41% for ankle & 79% for Foot) for ruling in facture, and not intended for specific diagnosis.

Considerations

• Palpate the entire distal 6 cm of the fibula and tibia.
• Weight bearing counts even if the patient limps.
• Precautions: Use clinical judgment if examination may be compromised for any of the following circumstances:
  • Intoxication
  • Distracting painful injuries
  • Gross swelling which prevents palpation of tenderness
  • Diminished sensation in legs
  • Uncooperative patient 

Rules

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

Indication: Patients ≥ 2 years with ankle or midfoot pain or tenderness in the setting of trauma

Precautions: Use clinical judgment if examination may be compromised for any of the following circumstances:

• Intoxication
• Distracting painful injuries
• Gross swelling which prevents palpation of tenderness
• Diminished sensation in legs
• Uncooperative patient