What is patellofemoral pain syndrome?

Patellofemoral pain syndrome is pain in the front of the knee. 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.

What causes patellofemoral pain syndrome?

Patellofemoral pain syndrome may be caused by overuse, injury, excess weight, a kneecap that is not properly aligned (patellar tracking disorder), or changes under the kneecap.

What are the symptoms?

The main symptom of patellofemoral pain syndrome is knee pain, 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.

How is patellofemoral pain syndrome diagnosed?

Your health professional will conduct a medical history and physical exam to determine the cause of your pain. In some cases, imaging tests including X-rays or magnetic resonance imaging (MRI) may be done. These tests allow a doctor to view the tissues inside your knee to rule out damage to the structure of the knee and the tissues connected to it.

How is it treated?

Patellofemoral pain syndrome can be relieved by avoiding activities that make symptoms worse.

• Avoid sitting or kneeling in the bent-knee position for long periods of time.
• Adjust a bicycle or exercise bike so that the resistance is not too great and the seat is at an appropriate height. The rider should be able to spin the pedals of an exercise bike without shifting weight from side to side, and the legs should not be fully extended at the lowest part of the pedal stroke.
• Avoid bent-knee exercises, such as squats, deep knee bends, or 90-degree leg extensions.

Other methods to relieve pain include:

• Taking nonprescription anti-inflammatory drugs (NSAIDs), such as ibuprofen or naproxen sodium, to decrease swelling, stiffness, and pain.
• Ice and rest.
• Physical therapy exercises. Exercises may include stretching to increase flexibility and decrease tightness around the knee, and straight-leg raises and other exercises to strengthen the quadriceps muscle.
• Taping or using a brace to stabilize the kneecap.
• Surgery.