You would just know that you need VMO exercises as the muscle above your kneecap is just not there anymore after surgery. I'm supposed to do as many as I can whenever I think of it....... Sitting on the edge of my chair I have to put the instep of my right foot into the heel of my left foot and push my instep/right leg into the left heel. You can see the VMO switch on. They are one vital exercise to help the knee track correctly especially as the out muscles of the quad will definitely be stronger.