Patellofemoral pain syndrome is pain in the front of the knee, originating from the region of the patella (kneecap) and femur (thigh bone). It frequently occurs in teenagers, manual laborers, and athletes. It sometimes is caused by wearing down, roughening, or softening of the cartilage under the kneecap.
Patellofemoral pain syndrome may be caused by overuse, injury, excess weight, a patella (kneecap) that is not properly aligned (called patellar tracking disorder), or changes to the patella.
When bending and straightening the knee, several muscles surrounding the joint act together to cause the patella to run in a straight line within the intercondylar groove, formed by the Femur and Tibia. If any of the structures are particularly tight or weak, this causes an imbalance which can result in the patella mal-tracking.
Patellofemoral pain syndrome can also occur following a knee injury if the muscles of the quadriceps, especially the vastus medialis on the inside become inhibited or considerably weakened. Other factors which can cause patellofemoral pain include:
You are more prone to this if you have a small kneecap or one that sticks out
If you suffer with tight muscles.
If you have weak quadriceps muscles.
Athletes who do a lot of long distance running or hill running.
Those who have had a previous knee dislocations
Symptoms of patellofemoral pain syndrome are an aching pain in the knee joint, particularly at the front of the knee around and under the patella. There will be tenderness along the inside border of the kneecap and swelling will sometimes occur after exercise.
The main symptom of patellofemoral pain syndrome which is knee pain is felt especially when sitting with bent knees, squatting, jumping, or using the stairs (especially going down stairs). You may also experience occasional knee buckling, in which the knee suddenly and unexpectedly gives way and does not support your body weight. A catching, popping, or grinding sensation when walking or with knee movement is also common.