An elderly person p/w R-knee pain after stepping off the curb a few days ago. There is  mild swelling and the patient does not like to bear weight on the extremity. You order a plain film of the knee and it looks okay. When you present to your seasoned attending, she tells you’ve missed a fracture. Where?

 

 

Tibial plateau fracture.

The plain films can be misleading, particularly in the elderly (who are at high risk for such an injury w/minimal mechanism) who have confounding OA findings as well. Sometimes the fracture can be quite subtle (like this one: http://www.bing.com/images/search?q=tibial+plateau+fracture+xray&view=detail&id=91E8318D88A5C593A3F0BD338712F0A8499F29AD&first=61&FORM=IDFRIR)
CT may/not be helpful. MRI is the best but you probably can’t get that…

Tips to diagnosing:
Look for it.
If there is bloody aspirate, check for floating fat; fat = fracture.

 If the fracture is signifcantly depressed or displaced, call ortho, as the patient probably needs surg. Otherwise or when in doubt, knee immobilizer w/strict non-wt bearing, RICE, PO pain control, prompt ortho f/up.

 

Ref:

Roberts, J. High Risk Orthopedic Injuries: Tibial Plateau Fracture. Emergency Medicine News. April 2012. Vol 34, No. 4;14-15.