Sports Medicine

Patellofemoral Pain Syndrome

Signs and Symptoms
Diagnosis
Treatment

Signs and Symptoms

The kneecap or patella is a small, triangular bone in the front of your knee that moves with the knee as it flexes. It glides up and down along a track at the end of the thighbone (femur) and gives the front thigh muscles (quadriceps) extra leverage for straightening the leg. The patella also protects the other bones in the knee against collisions and falls.

Patellofemoral pain syndrome occurs when the patella cartilage becomes overloaded due to overuse (often caused by high-impact activities) or as a result of poor alignment. High-impact sports -- such as football, basketball, soccer, tennis and running -- can aggravate existing abnormal kneecap alignment. In addition, running on uneven surfaces, like hills or trails, or playing on multiple surfaces (such as going from a grass to a hard court in tennis) also may increase the likelihood of patellofemoral pain.

The most common symptom of patellofemoral pain syndrome is a dull ache underneath the kneecap while walking down stairs, squatting or getting up after sitting for long periods of time. In addition, your knee may catch when bending, and you may experience a painful grating or creaking sensation.

Although many active people notice symptoms when starting new activities or increasing their level of intensity, especially with respect to high-impact sports, non-active people can suffer patellofemoral pain during routine daily activities as well.

Reviewed by health care specialists at UCSF Medical Center.
Last updated May 8, 2007