UMEM Educational Pearls

Title: Posterolateral knee injuries

Keywords: Knee instability (PubMed Search)

Posted: 7/23/2017 by Brian Corwell, MD
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PCL injuries can sometimes have involvement of the posterolateral corner (PLC)

The dial test can be used to diagnose posterior lateral instability and help differentiate it from isolated PCL injuries

The dial test involves comparing the amount of external rotation of the lower leg at the knee while the knees are in 30° and in 90° of knee flexion.

https://www.youtube.com/watch?v=rnk62Y-nDSQ

An isolated injury to the posterolateral corner will result in more than 10° of external rotation in the injured knee that is present at 30° but not at 90° of knee flexion.

http://www.kneejointsurgery.com/wp-content/uploads/2015/06/DIAL-TEST.jpg

http://www.kneejointsurgery.com/wp-content/uploads/2015/06/DIAL-TEST-90.jpg

References

http://www.kneejointsurgery.com/ligament-injuries/posterolateral-corner/