probably exercises will do it. get ankle weights, not too heavy. start out with the hamstring stretch on your back. then do 20 reps per leg, alternating, every two days of the following:
1. on back, left knee bent 30 degrees and raised (foot on floor), bring bent right knee back to your chest and then forward until your foot hits the floor.
2. on back, left knee in same position. holding right leg straight, lift up to height of right knee and down (the slower the better on this one, as you get stronger).
3. on right side, left knee in roughly the same position, bring straight right leg up to left knee height.
still on right side, bend right knee, leaving flat on ground, lift straight left leg to about the same height as before (the left leg will be in the horizontal plane of the left hip, while you lie on your side).
4. repeat those on the left side.
5. on stomach, with left leg straight, bend right knee and lift up, making sure that lower right leg is vertical.
6. sitting, with both legs straight on floor, tense both quads at the same time and hold for 3-5 seconds. x20.
7. sitting in a chair, high enough for your feet not to touch the ground, bring right knee slowly up to horizontal (or close to it, this exercise is hard on the knee, so be careful) and back down. x20.
8. standing, using your hand on the ankle, bring right foot back to rear and hold 30-40 seconds. once per day.
9. standing, try to bring right foot back with your hand while using your hamstrings to try to bring the foot forward. hold 30-40 seconds.
10. squats with a large elastic band on one side of the knees, the end of the band tossed on the other side of a door and the door closed to hold the band. these were tough for me to do because my left knee was so weak.
11. pretty key to break up the scar tissue, find the bone about two inches below the knee cap of the bad knee and push hard back and forth with your thumb or forefinger for a minute--only do this one every two days at most, and maybe less frequently.
this worked for me to run again, but maybe it's inappropriate for your injury.