Knee Pain in Active People

Patellofemoral Pain Syndrome: Patellofemoral pain syndrome is the most common cause of knee pain among active people between the ages of 15 and 30. It is commonly known as "Runner’s Knee" because of its high incidence in runners. According to the American Academy of Orthopaedic Surgeons, patellofemoral pain syndrome is felt as a dull, aching pain at the front of the knee and is usually felt during exercise, going up and down stairs, kneeling, squatting, or even sitting in a chair for a long period of time. Traditionally, doctors and other healthcare professionals have assumed that patellofemoral pain occurs more often in females than males. However, few studies have been done over the last thirty years to prove this assumption. Recently, researchers at the University of North Florida, the University of North Carolina at Chapel Hill, and the United States Naval Academy decided to investigate the prevalence and incidence of patellofemoral pain in both males and females in the 2009, 2010, and 2011 classes at the United States Naval Academy.

The investigators enrolled 1525 students, both athletes and non-athletes, from the United States Naval Academy into the study. The participants were enrolled as freshmen and were free of any injury that prevented them from taking part in the study’s functional tests. The investigators hypothesized that women would have higher rates of incidence and prevalence of patellofemoral pain than men. The investigators tracked each participant through their medical records and through the health care providers at the Naval Academy over the summers of 2005, 2006, and 2007. At the conclusion of the study, the investigators discovered that was a significant difference in the incidence of patellofemoral pain in women than in men. Females were more than twice as likely to develop patellofemoral pain during the study than men.

Why are women more likely to feel knee pain than men?

Women may have larger knee joint angles or "Q-angles" as shown in the picture to the left. Larger Q angles place more stress on the knee joint than the smaller Q angles. Women may have differences in movement patterns in the hip and knee, and may also have lower hip and thigh muscle strength in women than men. The American Academy of Orthopaedic Surgeons offers a few suggestions for prevention of patellofemoral pain syndrome: keep active, stretch before any exercise, increase your physical activity gradually, make sure your exercise equipment is right for your body, and use proper running form.

Examine your strength and running form using strength testing and motion analysis to see if there are mechanical factors affecting your running kinematics.

References:

• Boling M, Padua D, Marshall S, Guskiewicz K, Pyne S, Beutler A. Gender differences in the incidence and prevalence of patellofemoral pain syndrome. Scandinavian Journal of Medicine and Science in Sports. Sept 2009. DOI: 10.1111|j.1600-0838.2009.00996.x
• "Runner’s Knee (Patellofemoral Pain)" American Academy of Orthopaedic Surgeons. 2007. 29 Sept 2009.