Ottawa Ankle Rules
The Ottawa Ankle Rules are clinical decision guidelines designed to determine when radiographs are necessary for patients with acute ankle and foot injuries, with 99% sensitivity for detecting fractures while reducing unnecessary imaging by approximately 30%. 1
Foot Rules
A series of foot radiographs is required only if there is pain in the midfoot AND any one of the following:
- Point bone tenderness of the navicular 1
- Point bone tenderness of the base of the fifth metatarsal 1
- Inability to bear weight or walk 4 steps (immediately after injury or in the emergency department) 1
Ankle Rules
An ankle radiograph series is required only when:
- Bone tenderness along the distal 6 cm of the posterior edge of either malleolus 1, 2
- Inability to bear weight immediately after injury and in the emergency department 1, 2
Clinical Performance
- Sensitivity: 96.8-100% for detecting clinically significant fractures 1, 3
- Specificity: 26-45.8% for combined evaluation of ankle and midfoot 1, 3
- Adding swelling as a criterion increases sensitivity to 100% for the malleolar zone 1
- Can reduce unnecessary radiographs by 31-34% 2, 3
Exclusionary Criteria
The Ottawa Rules should not be used or should be used with great caution in the following situations:
- Penetrating trauma 1
- Pregnancy 1
- Skin wounds 1
- Patients transferred with radiographs already taken 1
- Injuries >10 days old 1
- Return visits for continued traumatic foot pain 1
- Polytrauma 1
- Altered sensorium 1
- Neurologic abnormality affecting the foot 1
- Underlying bone disease 1
- Age considerations: may need modification for geriatric patients (≥65 years) 4
Clinical Scenarios Not Addressed by Ottawa Rules
- Trauma to metatarsal heads and toes 1
- Penetrating trauma with concern for foreign body in soft tissues 1
Modifications and Alternative Rules
- Buffalo modification: improves specificity for malleolar fractures without sacrificing sensitivity 5
- Bernese ankle rules: alternative approach but with lower sensitivity (69-86%) 1
Implementation Pitfalls
- Ensure proper assessment of all criteria before ruling out the need for imaging 1, 3
- Be aware that occult fractures may be present despite negative radiographs in patients with positive Ottawa Rules (consider 3D-CT in these cases) 3
- The rules are validated for patients >5 years of age 1
- Consider age-specific modifications for elderly patients to improve sensitivity 4
Clinical Application
- Apply the rules systematically to all eligible patients with acute ankle or foot injuries 1, 2
- Document findings clearly, particularly weight-bearing ability and point tenderness 1, 2
- When properly applied, these rules can significantly reduce healthcare costs and patient waiting times without missing clinically significant fractures 2, 3, 6