Ottawa and Pittsburgh Knee Rules

Units: US SI

Ottawa

Patient should receive knee films if:

Blunt trauma or a fall as mechanism of injury AND either of the following:
- Age younger than 12 years or older than 50 years
- Inability to walk four weight-bearing steps in the emergency department

Stiell IG, Wells GA, Hoag RH, Sivilotti MLA, Cacciotti TF, Verbeek PR, Greenway KT, McDowell I, Cwinn AA, Greenberg GH, Nichol G, Michael JA. Implementation of the Ottawa Knee Rule for the Use of Radiography in Acute Knee Injuries. Journal of the American Medical Association 1997; 278:2075-2079.
Stiell IG, Greenberg GH, Wells GA, McDowell I, Cwinn AA, Smith NA, Cacciotti TF, Sivilotti MLA. Prospective validation of a decision rule for use of radiography in acute knee injury. Journal of the American Medical Association 1996; 275:611-615.
Stiell IG, Wells GA, McDowell I, Greenberg GH, McKnight RD, Cwinn AA, Quinn JV, Yeats, A. Use of Radiography in Acute Knee Injuries: Need for Clinical Decision Rules. Academic Emergency Medicine 1995; 2:966-973.
Stiell IG, Greenberg GH, Wells GA, McKnight RD, Cwinn AA, Cacciotti T, McDowell I, Smith NA. Derivation of a decision rule for the use of radiography in acute knee injuries. Annals of Emergency Medicine 1995; 26:405-413.

Age ≥ 55?	Yes
Isolated tenderness of the patella (no other bony tenderness)?	Yes
Tenderness at the fibular head?	Yes
Inability to flex knee to 90° ?	Yes
Inability to bear weight both immediately and in ED (4 steps, limping is okay).	Yes
Score	points
If none of the above criteria are met, according to the Ottawa Knee rules, imaging is not indicated.