per ESPN:
"Washington Redskins quarterback Robert Griffin III suffered a partially torn lateral collateral ligament in his right knee, a source told ESPN's Brett McMurphy.
Griffin also likely tore at least part of his anterior cruciate ligament (ACL), but it's unknown how severe it is because a previous knee injury he suffered at Baylor in 2009 required two screws and a rubber band to hold it together.
Because of the previous injury, doctors initially could not determine Monday if his ACL was partially or completely torn and doctors don't know what surgery should be performed.
The Washington Post reported earlier that Griffin's MRI suggested partial tears to the ACL and LCL."
For the rest of the article,
Link:http://espn.go.com/nfl/playoffs/2012/story/_/id/8822363/source-robert-griffin-iii-washington-redskins-partially-torn-lcl