• Patients with acute knee pain following trauma (blunt or fall).
• Screening for clinical indicators of fracture to reduce unnecessary imaging.
• Initial triage in the Emergency Department or sports clinic.

• Age ≥ 55 years.
• Isolated tenderness of the patella (no other bone tenderness).
• Tenderness at the head of the fibula.
• Inability to flex to 90 degrees.
• Inability to bear weight both immediately and in the ER (4 steps).

The Ottawa Knee Rule is designed to have nearly 100% sensitivity for detecting clinically significant fractures. A negative result effectively rules out fracture without the need for an X-ray.

• Weight bearing counts even if the patient limps; inability means complete inability to put weight on the limb.
• If the rules are applied correctly, they can reduce radiography rates by up to 26%.
• Always perform a thorough neurovascular exam regardless of the rule outcome.

• Any Criterion Present: Order Knee Radiograph (AP/Lateral/Sunrise).
• No Criteria Present: No X-ray required. Focus on soft tissue evaluation (Lachman, Thessaly, etc.).
• Symptom Progress: If pain fails to improve after 5–7 days, reconsider imaging.