If injury prevention is something that's been on your mind, adopting a good knee program should be a priority. A solid knee program will include both strengthening and stretch aspects to it to ensure the muscles are capable of dealing with not only the daily stressors that are placed on this joint but also that the joint itself can maintain a broad range of movement.
Some good exercises to perform in your knee program are squats, lunges and if you are currently not suffering any knee pain, leg extensions. Note that that exercise can be troublesome for a few individuals so if that is the case for you then you may want to avoid it.
Always remember to perform a proper warm-up before doing your plan because this joint in particular is prone to being stiff, especially in the mornings. When you first wake up you often hear cracks coming from inside the joint and this would be a good signal to you that you're a candidate who needs a thorough warm-up. The warm-up could be as simple as going on a treadmill for ten to fifteen minutes or else doing some gentle leg bends and squats.
If you are currently injured then it would be a smart idea to speak to a physiotherapist as they will likely have additional exercises for you to perform as part of your joint plan. Often these will include quad tenses with a towel. This is performed by placing a rolled up towel underneath the joint and then tensing the quad muscle so that it lifts the foot off the floor.
Don't forget as well the importance of rest and ice in your program. Along with the strengthening and stretching exercises it is always a good plan for both injury prevention and management.