Not sure what these guys are trying to do in putting this 'research' and news out, but this ligament is well known. It's the anterior oblique band of the LCL, and it's already known to be associated with ACL injuries.
Here's an example of it being studied 12 years ago:
http://www.ncbi.nlm.nih.gov/pubmed/11323461
There's nothing new about this - it's very misleading if they're acting as though it's a novel finding.
Edit: I read the journal article. They didn't say they discovered a new ligament, they just renamed the anterior oblique band and described it a bit more. Media providing misinformation as usual.