Sorry to hear of such a serious injury.
In replies to this recent thread I put together some information that I found related to tight/short rectus femorus muscles and how they stress the knees.
I believe that often the OPs think that I'm saying that this has caused their injury. I'm not. Of the many causes that may have caused or contributed to your injury this is just one to become aware of. It is simple, the fixes should normally be simple, so keep it in mind.
Have your posture evaluated and discuss this issue with your Dr and physical therapist. You will have a lot of physical therapy and evaluations so you should be well connected to some great information sources.
Good luck with your recovery, let us know how you do.