First, I recommend getting reevaluated by a orthopedic surgeon or physical therapist, since the injury occured in 2009. You do not know what the extent of the injury is after 6 years. If you have medical insurance, I would suggest going to a orthopedic "sports performance center" since they focus on athletes.
Having said that: I have had the same injury in my left knee (no surgery) and caught a small bit of shrapnel in my right knee( surgery, but, not major). So, yes, I have an idea what you are going through. On the advise of a good PT, I started riding a stationary bike for about three months, then switched over to a "spinning bike", began incline walks, later added weight for about 3 months, after 6 months started light land mine squats. I was lucky on both injuries and got back to fighting shape. To this day, I am a big believer in keeping your knees (tendons , ligaments) in shape and still use the same routine whenever I can. IMH and uneducated opinion, land mine squats are the safest way to bring a knee up to working order. They worked for me and I now have full range of motion with my MT and TKD kicks.
Sento, who is a regular here, is much more knowledgeable than me on human kinetics and I know he has encountered those injuries in some of his students, so, he may see this and offer you a more professional opinion. Good luck.