February 13, 2013 by EmerJencyWEBB
What are you worried about when you look at the radiograph above?
This radiograph demonstrates a medial tibial plateau fracture. Hopefully, 100% of Emergency Physicians will pick up on this. But we shouldn’t stop here, as this injury pattern is not cut and dry. This film should cause us to think MORE about potential associated injuries. Let’s talk about what those injuries could be.
The tibial plateau is one of the major weight bearing areas of the lower extremity, with the medial component responsible for a majority of the load at the knee. Also, as opposed to lateral tibial plateau fractures, the medial plateau injury is typically associated with higher energy mechanisms. The most common cause is a high force combination varus and axial load.
This injury is frequently associated with cruciate ligament disruption due to avulsion of the intercondylar eminence. Due to the common varus injury mechanism, the lateral collateral ligament may be injured as well. At this point, we are talking about a very unstable knee.
This is key to understanding why this fracture can be so devastating. With the amount of force required to create this injury, in addition to the instability created, you have to worry about potential knee dislocation. This is most important, as most of these injuries tend to have normalized alignment prior to obtaining a film.
Why do we worry about a knee dislocation that has already relocated?
The answer is, significant trauma to the neurovascular supply to the lower leg can occur at the time of injury. Dislocation or subluxation can create injury through traction on the peroneal nerve and may cause an intimal injury to the popliteal artery, which can lead to devastating thrombosis down the road. Compartment syndrome must always be in the back of your mind as well with knee dislocations.
So what do we do?
Re-examination of the limb is key, with emphasis on knee stability and neurovascular status of the lower leg if this has not already been performed.
Assess the Peroneal Nerve
Assess for Arterial Injury
Perform ABI or API Measurements on patients to rule out occlusive flow limiting lesion. (Remember, these measurements may be normal initially if a non-occlusive intimal tear has occurred)
Have a low threshold for advanced arterial imaging such as duplex ultrasonography or CT angiography, especially with abnormal ABI/API measurements.
Call your orthopedist and strongly consider admission for serial exams of both neurovascular status as well screening for compartment syndrome in the affected extremity.
I invite you to leave your thoughts, comments, and criticisms below.