Pittsburgh Knee Rules


A clinical decision rule used to indicate the use of radiography of the knee following an injury.


Radiographs of the knee should performed if the mechanism of injury is a fall or blunt trauma and either one of the following:

1) Patient is younger than 12 or older than 50

2) Inability to walk four weight-bearing steps

These rules do not apply to individuals who present more than 6 days after injury, those with only superficial lacerations and abrasions, those with a previous history of knee injury or surgery on the affected knee, and those being reassessed for the same injury. [1]


Diagnostic Accuracy

In a study by Seaberg et al., of 934 patients evaluated the Pittsburgh knee rules applied to 745 with a sensitivity of 0.99 and a specificity of 0.60.  There was the potential to reduce radiography by 52% with one missed fracture. [2]

In a more recent study by Cheung et al., the Pittsburgh knee rules had a pooled sensitivity of 0.86 and a pooled specificity of 0.51. [3]

Recommendations for Clinical Practice

The Pittsburgh knee rules are often compared to the Ottowa knee rules.  While the Pittsburgh knee rules have a higher specificity, each have almost identical sensitivities. [2][3] The ability of these rules to rule out a condition, and thus avoid a radiograph is important and their most valuable characteristics.  With proper training either set of rules could be adopted for use. [1]


  1. 1.0 1.1 Hawley C, Rosenblatt R. Ottowa and Pittsburgh rules for acute knee injuries. The Journal of Family Practice 1998;47(4):254-255. http://www.ncbi.nlm.nih.gov/pubmed/9789509. (Accessed 25 Apr 2013).
  2. 2.0 2.1 Seaberg DC, Yealy DM, Lukens T, Auble T, Mathias S. Multicenter comparison of two clinical decision rules for the use of radiography in acute, high-risk knee injuries. Annals of Emergency Medicine 1998;32(1):8-13. http://www.ncbi.nlm.nih.gov/pubmed/9656942. (Accessed 25 Apr 2013).
  3. 3.0 3.1 Cheung TC, Tank Y, Breederveld RS, Tuinebreijer WE, de Lange-de Klerk ES, Derksen RJ. Diagnostic accuracy and reproducibility of the Ottawa Knee Rule vs the Pittsburgh Decision Rule. American Journal of Emergency Medicine 2013;31(4):641-5. http://www.ncbi.nlm.nih.gov/pubmed/23399332. (Accessed 25 Apr 2013).