Chronic pain in the front and center of the knee (anterior knee pain) is common among active, healthy young people, especially girls.

It is usually not caused by any particular abnormality in the knee and does not mean that the knee will be damaged by continuing to do activities.

Pain located in the upper shinbone area below the kneecap is a different problem, and information about this can be found at Osgood-Schlatter Disease (Knee Pain)Osgood-Schlatter Disease (Knee Pain) (topic.cfm?topic=A00411)

In many cases, the true cause of anterior knee pain may not be clear. The complex anatomy of the knee joint that allows it to bend while supporting heavy loads is extremely sensitive to small problems in alignment, activity, training, and overuse. Pressure may pull the kneecap sideways in its groove, causing pain behind the kneecap.

In teenagers, a number of factors may be involved.

• Imbalance of thigh muscles (quadriceps and hamstrings) that support the knee joint
• Poor flexibility
• Problems with alignment of the legs between the hips and the ankles
• Using improper sports training techniques or equipment
• Overdoing sports activities

The pain usually begins gradually. You might experience these common symptoms:

• Popping or crackling sounds in the knee when you climb stairs or stand up and walk after prolonged sitting.
• Pain at night
• Pain during activities that repeatedly bend the knee (i.e., jumping, squatting, running, and other exercise, especially involving weight-lifting).
• Pain that causes your knees to give way (buckle), although this is uncommon
• Pain related to a change in activity level or intensity, playing surface, or equipment.

Thigh muscle (quadriceps) weakness may develop if the pain persists and limits your normal activity.

If your knee pain is lasting, see your doctor to diagnose the cause of the pain and to get treatment.

The adolescent anterior knee pain syndrome is not usually associated with symptoms like clicking, locking, snapping, or giving way of the knee. These symptoms suggest a mechanical problem in the knee and are reasons to see your doctor.

A standard knee examination will help your doctor determine the cause of pain behind your kneecap and rule out other problems. He or she may ask you to stand, walk, jump, squat, sit, and lie down. It is important to relax as best you can during the examination!

Your doctor may check:

• Alignment of the lower leg and the position of the kneecap
• Knee stability, hip rotation, and range of motion of knees and hips
• Under the kneecap for signs of tenderness
• The attachment of thigh muscles to the kneecap
• Strength, flexibility, firmness, tone, and circumference of front thigh muscles (quadriceps) and the back thigh muscles (hamstrings)
• Tightness of the heel cord and flexibility of the feet

If your pain is modest, but not severe enough for you to visit the doctor, then you can try the following conservative steps to help ease the discomfort. Ice, rest, and simple exercises are often helpful for teenagers with pain behind the kneecap. Non-steroidal anti-inflammatory drugs (NSAIDs), like ibuprofen, may also help particularly painful episodes.

If pain behind the kneecap is severe and persists, it is important to see your doctor so that a proper diagnosis can be made. However, if your pain has gone away but you have concerns about it returning, you may be able to prevent recurrences. Recommendations include:

• Wear shoes appropriate to your activities.
• Warm up with stretching exercises before physical activity.
• Stop or reduce any activity that used to hurt your knees.
• Limit the total number of miles you run in training and competition.