Patellofemoral Pain Syndrome - (Runner's Knee)

Patellofemoral pain syndrome (PFPS) is one of the most common knee disorders and is commonly referred to as “runner’s knee.” The patellofemoral joint is made of the kneecap (patella), thigh bone (femur), and soft tissues that provide support. The pain of runner's knee usually comes from these supporting structures. Among adolescents, 20 to 45 percent experience runner's knee. It is more than twice as likely to affect females as males. 

What Causes Runner's Knee? 

Runner's knee is usually caused by a combination of direct trauma, overuse, and abnormal kneecap movement (patellar tracking). The most frequent causes of abnormal patellar tracking include weakness in the thigh and hip muscles, too much movement of the kneecap, inadequate flexibility, and abnormalities of alignment between the hip, knee, and foot. Training errors, poor shoes, and running surface abnormalities can also aggravate runner's knee. 

What are the symptoms of Runner's Knee? 

The most common symptoms are pain during and/or after activity, and pain or stiffness after prolonged sitting or standing. Some people may also notice a grinding or popping feeling under the kneecap, and may experience mild swelling. The pain is usually dull and achy, and may shift from one side of the kneecap to the other. The athlete may have pain in both knees or only in one knee. The pain is usually worse when kneeling, walking downhill, or going up and down stairs.    

How is Runner's Knee diagnosed? 

The doctor will review the patient's history and physical examination.  X-rays, MRIs, and other imaging tests are usually not needed, unless the doctor needs to rule out another cause of the patient's symptoms. 

How is Runner's Knee treated? 

Treatment includes modifying activities and taking a breaking from those that cause symptoms. The mainstay of treatment is a customized physical therapy program to strengthen and stretch the hip and thigh muscles so they can help the kneecap move smoothly through its groove. Ice and anti-inflammatory medication can also reduce pain and inflammation. 

The doctor may recommend shoe inserts (orthotics) to redistribute pressures during activity. Some patients benefit from a brace or taping to support the kneecap and reduce pain during activity. Rarely, surgery may be necessary to help improve kneecap mobility if rest and physical therapy fail to relieve symptoms. 


Boling M, Padua D, Marshall S, Guskiewicz K, Pyne S, Beutler A. Gender differences in the incidence and prevalence of patellofemoral pain syndrome. Scand J Med Sci Sports. 2010;20(5):725-30. 

Anderson SJ and Harris SS, eds. Care of the Young Athlete, 2nd ed. Elk Grove Village, IL: American Academy of Pediatrics; 2010. 

Sarward JF and LaBella CR, eds. Pediatric Orthopaedics and Sports Injuries. Elk Grove Village, IL: American Academy of Pediatrics; 2010.