What causes patellofemoral pain syndrome?
For most growing athletes with patellofemoral pain syndrome, there are a collection of factors that cause the pain. Anything that increases the strain on the soft tissue supporting structures around the kneecap can lead to a problem with how the kneecap moves through its groove in the thigh bone as you bend and straighten the knee.
Patellofemoral pain syndrome can also result from direct trauma such as falling onto the kneecap or hitting the knee. It most commonly occurs from overuse of the knee in sports or activities that involve intense and repetitive running and jumping.
Activities of daily living such as prolonged sitting or standing, and going up and down steps, create extra pressure between the kneecap and the femur causing more stress and irritation. Some variants of normal hip, knee and foot alignment can put additional strain on the patellofemoral joint and supporting structures.
Growing athletes who are “flat-footed,” “knock-kneed,” or “pigeon-toed” tend to have higher rates of patellofemoral pain syndrome. Weak hip and thigh muscles are an important cause of patellofemoral pain. These muscles support the kneecap. When they are weak, the kneecap will not glide smoothly through its groove. This increases the strain on the kneecap’s supporting structures which causes pain.
A tight IT band (a tendon that runs along the outside of your thigh from your hip to your shin bone) is another risk factor for patellofemoral pain since it also helps to control the movement of the kneecap in its groove.
Finally, tight hamstrings are a frequent cause of patellofemoral pain, especially in growing bodies. Since muscles grow faster than bones, it is common for larger muscles to become relatively tight during growth spurts. Tight hamstrings increase the pressure behind the kneecap, which can lead to pain.