By gliding over cartilage where the shinbone and thigh, the kneecap (patella) offers important protection for the knee joint. With heavy stress induced by running and jumping, it is possible for the kneecap to fall out of alignment, putting abnormal pressure on surrounding cartilage around the front of the knee.
As the following video on patella realignment surgery demonstrates, the kneecap can become "off track" when lateral retinacula — bands of fibrous tissue surrounding the kneecap — pull the kneecap to one side. In patella realignment surgery, part of a retinaculum is cut, releasing the kneecap back to its normal position.
The orthopedics departments of John C. Lincoln Hospitals invite you to watch the following overview of patella realignment surgery.