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Patellofemoral Pain Syndrome


What is patellofemoral pain syndrome? Patellofemoral (pah-tel-o-FEM-or-al) pain syndrome, also called PFPS, is a condition marked by pain under or around the patella (kneecap). The pain usually occurs or worsens with activity or after sitting for a long time. The patella moves in different directions and comes into contact with the femur (thigh bone) when moving the knee. PFPS may happen due to the frequent contact and rubbing of the patella on the femur. It may also happen when the patella gets out of place. PFPS most commonly affects adolescents and young adults.

What causes patellofemoral pain syndrome? PFPS may be caused by any of the following conditions:

  • Foot problems, such as having a flat foot or high-arched foot. A flat foot has a tendency to roll inwards when walking or running. This causes the front thigh muscles to pull the kneecap outwards. A high-arched foot puts more stress on the leg as it provides less support when the foot touches the ground.

  • Increased activity, such as when doing heavy lifting or weight-bearing exercises.

  • Knocked-knee condition, where the legs curve inward at the knees.

  • Muscle problems, such as tight muscles in the back of the thigh or calf (back of the lower leg). Weak thigh muscles, which normally help keep the knee stable, may also lead to PFPS.

What are the signs and symptoms of patellofemoral pain syndrome? You may have any of the following:

  • A feeling that your knee is giving way.

  • Crepitus (creaking) when moving the knees.

  • Knee pain that is worse when going up or down the stairs, squatting, running, or cycling. Pain may also occur when you sit for a long time with the knees bent.

  • Swelling under the kneecap.

How is patellofemoral pain syndrome diagnosed? Your caregiver will check your knee to look for fractures (broken bones) or other problems. He may also look for swelling, warm skin, and the presence of crepitus. Your thighs or legs may be moved in different directions to test their range of motion. You may also have any of the following tests:

  • Arthroscopy: Your caregiver may want to look inside your knee to check for injuries or other problems. He will make a small incision (cut) on your knee and insert a scope through it. The scope is a long tube with a magnifying glass, a camera, and a light on the end.

  • Computerized tomography scan: This is also called a CT or CAT scan. An x-ray machine uses a computer to take pictures of your hips, thighs, or legs.

  • Magnetic resonance imaging: This is also called MRI. During the MRI, pictures of your knee or the area around it are taken. An MRI may be used to look for other problems that may be causing the knee pain.

  • X-rays: These are pictures of the bones and tissues in a part of your body. You may need x-rays of your hips, thighs, knees, or legs to look for fractures, arthritis, and other problems.

How is patellofemoral pain syndrome treated? Treatment aims to ease pain, keep the patella in the correct position with the femur, and prevent further problems. Activities that increase knee pain may need to be avoided. Ice may be applied on the knee to help ease pain and swelling. You may also have any of the following:

  • Assistive devices: Your knee may be taped into a certain position to decrease rubbing and pressure on your patellofemoral joint. A knee brace or sleeve may also be used. Your caregiver may want you to use crutches if putting weight on your leg causes pain. Using proper footwear or arch support may also be needed if a foot problem is causing your PFPS.

  • Medicines: Your caregiver may give you certain medicines to decrease the pain and swelling. Medicines that help increase bone thickness and build supporting muscles may also be given.

  • Rehabilitation: This is a program that helps your knee heal faster. You may do exercises to stretch and strengthen your hip, thigh, and calf muscles. These may include low impact activities, such as cycling, swimming, and walking. Exercises that bear weight and increase range of motion may also be done as the pain decreases.

  • Surgery: Surgery to correct a problem that is causing the PFPS may be done. Your caregiver may smooth out the back of the patella to decrease rubbing. A ligament in the knee may be cut to allow the knee to return to its normal position.

With treatment, such as rehabilitation and medicine, you may be able to fully recover and continue your normal daily activities.

Where can I find more information? Having a patellofemoral pain syndrome may be hard. Contact the following for more information:

  • American Academy of Family Physicians
    11400 Tomahawk Creek Parkway
    Leawood , KS 66211-2680
    Phone: 1- 913 - 906-6000
    Phone: 1- 800 - 274-2237
    Web Address:
  • American Academy of Orthopaedic Surgeons
    6300 North River Road
    Rosemont , IL 60018-4262
    Phone: 1- 847 - 823-7186
    Web Address:


You have the right to help plan your care. Learn about your health condition and how it may be treated. Discuss treatment options with your caregivers to decide what care you want to receive. You always have the right to refuse treatment.

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The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

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