Running Series: What is Patellofemoral Pain?

Anyone who has taken up running is likely to encounter knee pain at some point during their running journey. There can be several causes of knee pain, but let’s start with an intro to the anatomy. 

The knee is a hinge joint that involves three bones: the femur, tibia, and patella. The fibula is not directly involved in the knee joint, but due to several muscle and tendon attachments, it is also an important bone in the function of the knee. These bones come together to make two joints, the tibiofemoral and the patellofemoral joints. We will focus on discussing patellofemoral pain as it accounts for up to 25% of the running-related injuries.

Patellofemoral pain Syndrome (PFPS)

The patella is a bone that is not connected to any other bones by the usual means. Most joints in the body are connected via ligaments, but the patella floats over a groove in the femur and is completely dependent on the leg muscles to control its movement. It acts like a pulley for our quadriceps muscles which allows for greater force production. As the demands on our legs increase, the patella relies heavily on the surrounding muscles to maintain proper function. When it comes to running, we require our lower body to absorb up to 3 times our body weight with each step. This is a significant jump from simply walking and if our muscular coordination and endurance is not sufficient, our bodies compensate to complete the task. If the knee muscles fatigue, or become weak, then the patella is susceptible to excessive forces which causes inflammation and pain. 

The role of the hip in patellofemoral pain has been confirmed as a major cause of knee pain by recent studies that used advanced imaging to observe that irregular movement of the femur causes the femur and patella to make excessive contact. The hip is also the most powerful part of the human body. Just about every complex sporting activity heavily relies on the hip to generate power. Some examples are: jumping, spriniting, throwing, swinging, punching and kicking. With these activities, the hip acts like the accelerator in our cars. However, when it comes to endurance running, the hip has an additional role. The hip muscles are used to minimize the flexion and rotation of the femur to help stabilize our pelvis and knee. Without this, our pelvis would drop and our knees would buckle inwards with every step. In this aspect, think of the hip muscles acting the brakes in your car. 

Thus, when dealing with knee pain, these factors highlight the importance of a thorough assessment that checks the joints/structures to locate the source of dysfunction. Once the cause of the injury is found, it is more effective to treat and create a preventative plan of action.

To learn more about how Ace Sports Clinic can help you with your knee pain and running goals, contact us today and book an initial assessment with one of our expert Ace Certified Practitioners such as Chiropractors, Physiotheraspists and Osteopathic Manual Practitioners.

Written by Dr. Mike Rumeo, DC for Ace Sports Clinic

Sources:

1. Devereaux M, Lachman S. Patellofemoral arthralgia in athletes attending a sports injury clinic. Br J Sports Med,1984;18:18-21.

2. Nilsson J, Thorstensson A. Ground reaction forces at different speeds of human walking and running. Acta Physiol Scand. 1989 Jun;136(2):217-27. doi: 10.1111/j.1748-1716.1989.tb08655.x. PMID: 2782094.

3. Souza R, Draper C, Fredericson M, et al. Femur rotation and patellofemoral joint kinematics: a weight-bearing magnetic resonance imaging analysis. J Orthop Sports Phys Ther, 2010;40:277-285.