Along with maintaining a good healthy lifestyle, here are a few simple and easy moves (from greatist.com by Erin Kelly) that you can try to eliminate knee pain for good. Obviously, use caution with these moves and you may want to ask your therapist which move is the best for your knee situation.
6. Straight Leg Raise
For more in depth reasoning on why these stretches will help your knee, and the proper way to perform each one click on the link below.