That brings back nightmares for me. About a year and a half ago I was playing basketball and went to jump up and my patellar tendon ruptured. When I hit the ground my kneecap was on the side of my knee. This totally screwed up all of the MMA and BJJ progress that I made. I was in a full leg cast for 10 weeks and when the cast came off my leg was half of it's normal size. Anytime you sustain this type of injury getting your strength, coordination and flexability back takes a long time.
Anyways, I am just now getting my pre-injury status back. I started training BJJ and MMA again. My doctor told me that I can resume my pre-injury activities and I'm actually starting to hang once again in training.
The hardest thing about this type of injury is that it really messes with you MENTALLY. This whole thing made me realize that your physical ability can be taken away at any time. I got a small taste of what its like to be disabled and I never want to experience that again.
Anyways, I'm now injury free (knock on wood) and back at it. Train safe and cherish that you are able to train.