This is an excellent 3D graphics video that explains the entire process of anterior cruciate ligament (ACL) reconstruction. The video explains what an ACL is, and why it is important to the knee. It shows you a lot about how the human knee works, where its weaknesses are, and how far surgery has come in recent years.
It's amazing to think that as recently as the late 1980's, a ruptured ACL use to be the end of a sports career. The only way to repair such an injury was by open knee surgery, which had a very long and painful recovery. The surgery itself was such a traumatic insult to the knee that it was almost as bad as the injury. I have seen horrible scars from reconstructive knee surgery from back in that era.
It reminds me of an old Star Trek movie:
Well, we're not quite there yet, but you get the idea. Faster, please. And get well soon, Nerlens.