Following up from last week’s post on the Ottawa ankle rules, we’ll be reviewing the two popular knee protocols; the Ottawa knee rules and the Pittsburgh knee rules.

 

Knee fractures are terrible injuries likely requiring surgery and serious rehabilitation time before the patient is able to return to the community and return to play. Similarly to the ankle situation, knees were being x-rayed far too often with only 6% of x-rays positive for fracture. This costs time and money all around.

 

In 1995, Doctors in Ottawa began reviewing cases where fractures were found and determined a pattern. Following a 5-point procedure they reduced the frequency of knee x-rays in their initial study by 28%! The original 5 point procedure was found to have 100% sensitivity and 79% sensitivity.

At the same time, doctors in Pittsburgh were performing a similar study with similar aims. They developed a 3 point protocol which results in results of 99% sensitivity and 60% specificity.

 

10 year reviews of these protocols have produced the following results; the Ottawa knee rules have 97% sensitivity and 27% specificity. The Pittsburgh knee rules were 99% sensitive and 60% specific. Radiographic imaging was cut by 50%. If both rules indicated a fracture was present, 25% of the time one was. If they indicated a fracture was not present, 0.2% one was missed. These basic protocols can be easily implemented and should be used wherever possible.

 

Ottawa knee rules: X-ray is indicated if any of the following accompanies a history of blunt trauma or falling;

Younger than 12 or older than 50

Tenderness at the head of the fibula

Isolated tenderness on the patella

Inability to flex to 90 degrees

Cannot weight bear for 4 steps

 

Pittsburgh knee rules: X-ray is indicated if any of the following accompanies a history of blunt trauma or falling;

Younger than 12 or older than 50

Cannot weight bear for 4 steps.

 

Clearly the Pittsburgh protocol is shorter and easier to recall. On field therapists, coaches and anyone involved in athletics should take note if post-fall, an athlete can’t weight bear for 4 steps, a drive over to a hospital for assessment is strongly indicated.