Understanding the knee: Patellofemoral syndrome

Do you ever experience pain in the front of your knee that occurs during or after a sporting activity? There are several causes that can explain the presence of such pain. Among these we find patellofemoral syndrome.  


What it is?  

Patellofemoral syndrome is characterized by symptoms that originate from the joint in front of the knee which is located between the kneecap and the femur (the patellofemoral joint). This is usually an irritation of the cartilage that lines the surface of the joint.  

When you bend and unfold your knee, the kneecap slides into a small groove located at the front of the femur. The quadriceps, the large muscle in the front of the thigh, passes above the kneecap to attach to the front of the leg. When the quadriceps contracts, the patella experiences compression in its groove on the femur. If we start a new activity or sport that involves strong, repeated contractions of the quadriceps, sometimes the resulting compression and friction exceed our capacity. Thus, the cartilage under the kneecap can become irritated and patellofemoral syndrome can appear.  


Who could have it? 

Patellofemoral syndrome mainly occurs in individuals practicing sports that use the quadriceps muscles of the thigh, such as running, jumping or hiking. This syndrome often occurs when there is a change in activities, including the practice of a new sport, a new training surface, an increase in training volume, etc. It can also affect some people during activities of daily living that involve repeated bending and extension of the knees, such as going up and down stairs or during squat movements. People of all ages can suffer from patellofemoral syndrome, but young girls in their teens are particularly likely to be affected by this syndrome. This could possibly be explained in part by the physical changes linked to the growth spurt of girls which would lead to certain muscular imbalances in the pelvis and lower limbs.  


What does it look like?  

This is a deep knee pain, often in the front, that occurs during or after sporting activity. Symptoms can be felt in different places, for example in the soft tissues around the kneecap.  


How can physiotherapy help?  

You must first identify the movements or activities that trigger the symptoms in order to properly control the intensity of stress on the patellofemoral joint. To improve your capacity and strengthen your joint, it is essential to regularly impose load on the joint, but in a less intense manner. The right mix of intensity and duration of activities is the key to success.  

It may also be relevant to identify movement defects and muscle weaknesses that lead to overload in the knee. Your physiotherapist could help you by teaching you motor control, strengthening and proprioception exercises. The latter will guide you throughout your progress towards resuming your favourite activities and sports!