The patella rests within a groove on top of the femur known as the trochlear groove. Whenever you bend and straighten your knee, the patella moves backwards and forwards inside of this groove. This differs from a total knee replacement, in which bone and cartilage from your entire joint are changed. Your http://knee cap replacement https://www.theorthopaedicandpainpractice.com/knee-cap-replacement-understanding-the-basics-of-this-orthopaedic-surgery/