🦵 Ottawa Knee Rule
Decide whether a knee X-ray is needed after acute injury with the Ottawa Knee Rule.
Ottawa Knee Rule
Age ≥ 55
Isolated tenderness of the patella
Tenderness at the head of the fibula
Unable to flex to 90°
Unable to bear weight 4 steps (then & now)
When to use
Reduce unnecessary knee radiography in the ED.
How it works
X-ray if any: age ≥ 55, isolated patellar tenderness, fibular head tenderness, inability to flex to 90°, or inability to bear weight 4 steps.
Key points
- Highly sensitive for clinically significant fractures.
- Apply to alert adults with acute isolated injury.
- Inability to bear weight = both immediately and in the ED.
References
Decision support for licensed clinicians only; not a substitute for clinical judgement, diagnosis or local protocols.