Pittsburgh Knee Rule

Assist with detection of knee fractures and decision to x-ray


The Pittsburgh Knee rule was derived by Seaberg et al. 1994 as a sensitive clinical decision rule to help clinicians determine when an x-ray is required for patients presenting with acute knee pain. The rule has been externally validated to provide a 99% sensitivity and 60% for the detection of knee fractures in patients with knee pain in the setting of blunt trauma or fall injuries.

This rule is one of two commonly used clinical tools for acute knee pain, the other being the Ottawa Knee rule. These have been compared head to head since their derivation including in the initial external validation for the Pittsburgh rule. That study (Seaberg et al. 1998) found that the Pittsburgh Knee rule had a greater sensitivity and specificity (99% and 60%) compared to the Ottawa Knee rule (97% and 27%). One advantage to the Pittsburgh rule is that unlike the Ottawa rule, it can be applied to patients less than 18 years old.

Variable & Associated Points

  • Mechanism blunt trauma or fall
  • Age < 12
  • Age > 50
  • Inability to walk 4 weight bearing steps in the ED

If "Yes" to the mechanism criteria:

  • Radiography recommended if any other criteria satisfied
  • Radiography not recommended if no other criteria satisfied

If "No" to the mechanism criteria:

  • Rule does not apply if mechanism criteria is not met


Seaberg DC and Jackson R.

American Journal of Emergency Medicine 1994, 12 (5): 541-3

Seaberg DC, Yealy DM, Lukens T, Auble T, Mathias S.

Annals of Emergency Medicine 1998, 32 (1): 8-13

The Pittsburgh Knee Rule calculator is created by QxMD.

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1. Mechanism of injury blunt trauma or fall?

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