Purpose: The Pittsburgh Knee Rules were developed in order to determine the need for radiographs after acute knee injury secondary to the risk of fracture.
Rule:
Blunt trauma or a fall as mechanism of injury PLUS either of the following:
1. Age older than 50 years or Younger than 12 years
2. Inability to walk 4 weight-bearing steps in the emergency department
| Item | |
| SN | 0.99 |
| SP | 0.60 |
SN = sensitivity – ‘SnOut’ helps rule out a disease (higher number is better – >0.9 is excellent)
SP = Specificity – ‘SpIn’ helps rule in a disease (higher number is better – greater than 0.90 is excellent))
+LR = positive likelihood ratio – ratio of positive test results in a patients with the pathology (true positives) higher number is better (> 10 is excellent)
-LR = negative likelihood ratio – ratio of negative test results in a patients with the pathology (false negatives) lower number is better (< 0.1 is excellent)
PPV = positive predictive value – percentage of patients who both test positive & have the disease (true positives)
NPV = negative predictive value – percentage of patients who both test negative & do not have disease (true negatives)
References:
1. Bauer SJ, et al. A clinical decision rule in the evaluation of acute knee injuries. J Emerg Med. 1995; 13(5): 611-5.
2. Cheung TC, et al. Diagnostic accuracy and reproducibility of the Ottawa Knee Rule vs the Pittsburgh Decision Rule. Am J Emerg Med. 2013; 31(4): 641-5.
3. Seaberg DC, et al. Clinical decision rule for knee radiographs. Am J Emerg Med. 1994; 12(5): 541-3.
4. Seaberg DC, et al. Multicenter comparison of two clinical decision rules for the use of radiography in acute, high-risk knee injuries. J Emerg Med. 1995; 13(5): 611-5.
