Pittsburgh knee rules

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

Criteria

• 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.

Accuracy

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%.

The false positive result is less important as if the patient is positive, they should receive an Xray to assess for a possible fracture which has a much higher specificity.

The use of the Pittsburgh Knee rules reduces the use of knee radiographs by 52%.^[1]

References