Patellofemoral syndrome is a common overuse injury for people who are runners. Females have a higher risk and most frequent in teenagers and young adults. The condition develops from too much running especially downhill but also occur in people who do excessive knee bending like jumpers, skiers, cyclist, weight lifters, and soccer players. The primary symptom is dull pain around the posterior part of the knee including the area under the patella. The pain usually occurs when running, walking, climbing up and down a stairs, kneeling, squatting, or sitting with knee bent for a long period of time.
Runner’s knee may be triggered by various causes which includes the shape and motion of the patella, physical impact to the patella, or excessive running with improper shoes. These factors may cause disparity in the muscle that pulls the patella and allows it to drift towards the lateral side of the patellar surface on the distal femur.
Females have wider pelvis which results in a greater Q-angle (see photo) than males. When the knees are extended, the quadriceps femoris muscle pulls the patella upward and laterally, but the lateral pull is greater in females due to their large Q-angle which makes them more susceptible in developing the syndrome.
The lateral side of the patellar surface of the femur has a lip that makes up for the lateral pull on the patella and helps maintain its normal tracking. But, if the pull of the quadriceps femoris muscle by the medial and lateral sides is not balanced, the patella may drift towards the lateral side. If this happens all the time such as in excessive running, pain will occur and damages the articulating surface of the patella and femur. People with patellofemoral syndrome have a higher risk in developing arthritis. Treatment includes ceasing the activity that causes knee pain for a period of time and then gradually resuming the activity. Additionally, correcting the pull imbalances which includes strengthening of the quadriceps femoris is necessary to avoid reoccurence.
OpenStax Anatomy and Physiology. Runner’s Knee. Homeostatic Imbalances. Accessed November 10, 2019