Ottawa Knee Rules

Describes criteria for knee trauma patients so low risk as not to warrant knee imaging.

Age ≥ 55

Isolated tenderness of the patella (no other bony tenderness)

Tenderness at the fibular head

Unable to flex knee to 90°

Unable to bear weight both immediately and in ED (4 steps, limping is okay)


Source: Stiell IG, et al. Derivation of a decision rule for the use of radiography in acute knee injuries. Annals of Emergency Medicine. 1995; 26(10): 405-13.