For adults with acute blunt knee trauma. Apply with caution if the examination is unreliable (intoxication, distracting injury, altered sensation) or the presentation is delayed.
Age ≥ 55 years
Isolated tenderness of the patella (no other bony knee tenderness)
Tenderness at the head of the fibula
Unable to flex the knee to 90°
Unable to bear weight (4 steps) both immediately and in the department
Evidence
Original publication
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.
Annals of Emergency Medicine, 1995
Open source
Validation
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%.
JAMA, 1996
Open source
Guideline
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.
Last reviewed: 2026-09
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