Radiographs
In the absence of reliable evidence, it is the opinion of the work group that in the initial evaluation of a person with a knee injury and associated symptoms [giving way, pain, locking, catching] and signs [effusion, inability to bear weight, bone tenderness, loss of motion, and/or pathological laxity] that the practitioner obtain AP and lateral knee xrays to identify fractures or dislocations requiring emergent care.

Rationale
While recognizing that various criteria for performing knee radiographs have been published, the consensus opinion recommends that practitioners initially evaluating a patient with an acute knee injury should obtain AP and lateral radiographs of the knee.  In the setting of acute knee injury, radiographs may lead to the diagnosis of fracture, dislocation, ligament disruption, neoplasm, foreign body, and/or soft tissue injury that could lead to loss of the limb or limb function. Early diagnosis of these disorders may decrease morbidity from the injury.

If a MRI or CT scan is already available additional radiographs may not be necessary. This recommendation is consistent with current practice.

Benefits of Implementation
Potential early recognition of clinically important knee injury enhances patient care.

Possible Harms of Implementation
X-ray exposure.

Future Research
Adequately powered study to evaluate the sensitivity and specificity of methods used in the initial evaluation of acute knee injury; symptoms and physical signs, plain radiographs, MRI scan, and CT scan.
 

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