EXPLODING BACTERIAMed Decision Speed Tools
ED Decision Tools

Ottawa Ankle Rule

Determines which ankle/midfoot injuries need X-rays — two independent decisions: an ankle series, a foot series, both, or neither.

Ankle X-ray (malleolar zone)
No ankle X-ray required
No malleolar-zone criteria met
Foot X-ray (midfoot zone)
No foot X-ray required
No midfoot-zone criteria met
Ankle X-ray criteria (malleolar zone)
Bone tenderness at posterior edge or tip of LATERAL malleolus
Bone tenderness at posterior edge or tip of MEDIAL malleolus
Foot X-ray criteria (midfoot zone)
Bone tenderness at base of 5th metatarsal
Bone tenderness at navicular bone
Shared criterion (applies to BOTH zones)
Inability to bear weight (4 steps) immediately after injury AND in the ED
Stiell IG, et al. 1992 · Sensitivity ~98–99.6% for clinically significant fractures · Adults and children ≥5 years. Does NOT assess the proximal fibula (Maisonneuve) or Achilles tendon — examine those separately.