Ottawa Ankle Rules: Areas of Tenderness Requiring X-ray
An ankle x-ray is required if there is bone tenderness along the distal 6 centimeters of the posterior edge or inferior tip of either the medial or lateral malleolus. 1
Specific Anatomical Locations for Ankle X-ray
The Ottawa Ankle Rules mandate radiography when point tenderness is present at:
- Posterior edge or inferior tip of the lateral malleolus (distal 6 cm) 1
- Posterior edge or inferior tip of the medial malleolus (distal 6 cm) 1
Additionally, x-ray is indicated if the patient has inability to bear weight both immediately after injury AND in the emergency department (defined as inability to walk 4 steps). 1
Specific Anatomical Locations for Foot X-ray
A foot x-ray series is required if there is pain in the midfoot AND any of the following:
- Point bone tenderness at the navicular bone 1
- Point bone tenderness at the base of the fifth metatarsal 1
- Inability to bear weight or walk 4 steps (immediately after injury or in the emergency department) 1
Clinical Performance
The Ottawa Ankle Rules demonstrate excellent sensitivity (92-100%) with moderate specificity (16-51%) for detecting fractures, making them highly reliable for ruling out fractures when negative. 1 The rules have been validated in both adults and children over 5 years of age. 1
Important Caveats
The Ottawa Ankle Rules should NOT be applied in the following situations:
- Patients with peripheral neuropathy or altered sensorium 1
- Pregnancy 1
- Penetrating trauma or open wounds 1
- Injuries more than 10 days old 1
- Return visits for the same injury 1
- Polytrauma patients 1
- Patients with underlying bone disease 1
In these exclusionary scenarios, clinical judgment should guide imaging decisions rather than strict adherence to the rules. 1
Age Consideration
For patients ≥65 years of age, consider a lower threshold for imaging as the specificity of the Ottawa Ankle Rules drops significantly in geriatric populations (33% versus 60% in younger patients), though sensitivity remains high. 2