Ottawa Knee Rule

Stiell IG, Greenberg GH, Wells GA, et al. Derivation of a decision rule for the use of radiography in acute knee injuries. Age ≥ 55, isolated patellar tenderness, fibular head tenderness, inability to flex to 90°, or inability to bear weight identified all clinically important fractures.

Stiell IG, Greenberg GH, Wells GA, et al. Prospective validation of a decision rule for the use of radiography in acute knee injuries. The rule was 100% sensitive for fractures and could have reduced knee radiography by ~28%.

Widely used for acute knee trauma in adults; like the ankle rules, apply with caution when the examination is unreliable (intoxication, distracting injury, altered sensation) or presentation is delayed.