The Ottawa knee rules are a set of rules used to help physicians determine whether an x-ray of the
knee
In humans and other primates, the knee joins the thigh with the leg and consists of two joints: one between the femur and tibia (tibiofemoral joint), and one between the femur and patella (patellofemoral joint). It is the largest joint in the hu ...
is needed.
They state that an X-ray is required only in patients who have an acute knee injury with one or more of the following:
* Age 55 years or older
* Tenderness at head of
fibula
The fibula (: fibulae or fibulas) or calf bone is a leg bone on the lateral side of the tibia, to which it is connected above and below. It is the smaller of the two bones and, in proportion to its length, the most slender of all the long bones. ...
* Isolated tenderness of
patella
The patella (: patellae or patellas), also known as the kneecap, is a flat, rounded triangular bone which articulates with the femur (thigh bone) and covers and protects the anterior articular surface of the knee joint. The patella is found in m ...
* Inability to flex the knee greater than 90°
* Inability to bear weight both immediately and in the emergency department (4 steps)
The Ottawa knee rules were derived to aid in the efficient use of radiography in acute knee injuries and have since been prospectively validated on multiple occasions in different populations and in both children and adults. Some studies found the
sensitivity of the Ottawa knee rules is 98-100% for clinically significant knee fractures, meaning that 98-100% of all patients with a fracture will meet the criteria for X-ray. However,
specificity for the Ottawa knee rules is typically poor, meaning that a significant proportion of those who meet Ottawa knee criteria will have no knee fracture on X-ray. The
Pittsburgh knee rules
The Pittsburgh knee rules are medical rules created to ascertain whether a knee injury requires the use of an 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 y ...
have been found to be more specific in diagnosis.
Clinical decision guidelines such as these not only avoid
unnecessary health care
Unnecessary health care (overutilization, overuse, or overtreatment) is health care provided with a higher volume or cost than is appropriate.
In the United States, where health care costs are the highest as a percentage of GDP, overuse was the ...
and its costs but also help minimize exposure to ionizing radiation. Such radiation is necessary for radiography but may raise risk for cancer, so physicians
try to avoid using it whenever practical.
See also
*
Ottawa Ankle Rules
In medicine, the Ottawa ankle rules are a set of guidelines for clinicians to help decide if a patient with foot or ankle pain should be offered X-rays to diagnose a possible bone fracture. Before the introduction of the rules most patients with a ...
*
Pittsburgh knee rules
The Pittsburgh knee rules are medical rules created to ascertain whether a knee injury requires the use of an 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 y ...
External links
Pittsburgh Knee Rules
Diagram of Ottawa knee rules
References
Emergency medicine
Orthopedic clinical prediction rules
Examination of the knee
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