First I have heard anyone say he tore ligaments.
I was under the impression he tore his meniscus. The typical care for this is to cut the torn part out and recovery is very short. Here is info on Jack's surgery:
http://www.insidesocal.com/ucla/201...s-recovery-timetable-after-his-meniscus-tear/
In this case, this is rehabilitating a meniscus injury.
The long term issue is with the cartilage in his knee. He has an osteochondral defect, where the cartilage is separating from the bone. Per this article.
http://www.nfl.com/news/story/0ap30...ble-to-draft-slide-due-to-concerns-about-knee
As far as the Dr. Andrews report, my understanding is that Dr. Andrews is saying he doesn't need microfracture surgery now. It doesn't mean he won't need it in the future, and given the documented osteochondral defect, it is more likely that he will need it compared to someone without it. As far as I am concerned, it makes no difference because we didn't draft him.