Pittsburgh knee rules

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The Pittsburgh knee rules are medical rules created to ascertain whether a knee injury requires the use of X-ray to assess a fracture.


  • 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.

If the patient satisfies the above criteria, they should receive an X-ray to assess for a possible fracture.


The sensitivity of using the Pittsburgh knee rules is 99% with a specificity of 60%. That means the use of the above rules has a false negative result of 1% and a false positive result of 40%.[1]

The false positive result is less important as if the patient is positive, they should receive an X-ray to assess for a possible fracture, which has a much higher specificity. However, the Pittsburgh knee rules offer less false positives than do the Ottawa knee rules, though the Ottawa knee rules are more commonly used. [2]

The use of the Pittsburgh knee rules reduces the use of knee radiographs by 52%.[3]

See also[edit]


  1. ^ Seaberg DC, Jackson R (1994). "Clinical decision rule for knee radiographs.". Am J Emerg Med 12 (5): 541–3. PMID 8060409. 
  2. ^ MDCalc. "Pittsburgh Knee Rules". MDCalc. Retrieved 2014-10-15. 
  3. ^ Tandeter HB, Shvartzman P (December 1999). "Acute knee injuries: use of decision rules for selective radiograph ordering". Am Fam Physician 60 (9): 2599–608. PMID 10605994.