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Ottawa knee rule
Determines need for knee radiography after acute injury.
Ottawa knee rule
Age ≥ 55 years
Tenderness at the head of the fibula
Isolated tenderness of the patella
Unable to flex the knee to 90°
Unable to bear weight 4 steps (immediately and in ED)
ResultNo radiograph needed
No criteria met — clinically significant fracture is very unlikely.
When to use
- Excluding fracture in acute knee injury to reduce unnecessary radiography.
Formula
Knee x-ray if any of: age ≥ 55, isolated patellar tenderness, fibular-head tenderness, inability to flex to 90°, inability to bear weight for 4 steps.