My experience with Knee Injuries
I blew my knee out when I was 15 years old playing highschool football. I didn't tear any ligaments (The way the doctor explained it to me was that instead of the ACL tearing, the section of bone where it was connected broke off,leaving a peice of bone partially broken off.) Instead of surgically correcting it, they opted to put a stove-pipe cast from my hip to ankle. Looking back I really wish they had given me surgery since I'm still having a lot of problems with my knee. Occasionally when I run hard,pivot, job,walk etc I get a sharp pain in my knee and it locks for a few seconds.
Anyways,on to the reason I posted this,
When I got my cast taken off (only 6 weeks) I still had a reasonably strong leg but my knee felt terribly unstable. (most of it was probably mental)
Doctor told me Physiotherapy wasn't necessary (what a guy) so I went to my local gym and asked a trainer to hlep make up a program that would loosen up and strengthen my knee.
I found stationary bike a great way to regain my range of motion without putting and pressure on my knee.
For leg exercises I started using simple machines, Leg Extension,Leg Curl,Hip Sled with 0 weight (Not even the bar for extensions or Curls,just sitting on the machine and going through the motions). I could do these exercises with weight but it would cause a great deal of tightness in my knee. After a few weeks my knee loosened up and I cuold go back to training hard.
This post was probably completely useless, aw well,I tried.