The patella (knee cap)  is a flat, rectangular bone that protects the knee joint and helps the leg move more efficiently. A healthy patella glides up and down a groove at the head of your femur (thighbone). Overuse, muscle imbalances or weaknesses can cause the kneecap to become misaligned

The video below will give you a general overview of the procedure to remove damaged cartilage that can cause patella pain.  Your own surgery may vary depending on the extent of the damage and the judgment of your surgeon.