Kneecap pain is a common problem and occurs when it is out of alignment.
There are several causes for the kneecap, or patella, to become misaligned including: flat feet, weak hip muscles (which cause the femur to move out of its precise alignment), leg length differences, tight muscles on the front and back of the upper leg, weak quadriceps, or tight tendons.
Treatment involves identifying and addressing the cause and modifying activities accordingly. Applying ice to the knee for 15 to 20 minutes several times a day can help, as well as taking acetaminophen (Tylenol, others) as directed.
A doctor or physical therapist can recommend at-home exercises and stretches that can help most people reduce knee pain, including hamstring stretches and exercises that strengthen leg muscles. Doing the recommended activities twice daily for four to six weeks is generally suggested. After that a maintenance program of exercises and stretches 3 to 4 times a week helps stabilize the knee.
As reported by the Mayo Clinic Newsletter.