There are also regular, sticky bandages made specifically for knees. Since the knee has a unique structure and bends, regular bandages do not fit well. They usually fall off or crease and prevent movement. So some bandage manufacturers have made bandages with a unique shape to suit the knee area. The same type of bandages are also used for the elbows.
I bought a box of knee bandages after seeing my boys come home with lots of scrapes on their knees from playing and riding the bicycle. I bought the cushion type so that the bandage also serves as protection in case they fall again.