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Regional Medical Center of San Jose
Good Samaritan Hospital

Patellofemoral Pain Syndrome


Patellofemoral pain syndrome is a condition in which pain is felt under the kneecap. The patella is the bone that makes up the kneecap. The femur is the thigh bone. This bone forms the upper part of the knee. In patellofemoral pain syndrome, the patella rubs painfully against the femur.

This pain occurs during exercise or movement. It is most common during weight bearing activities such as running.

The Kneecap
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The pain is the result of inflammation of soft tissues around the kneecap. It can be due to a number of different factors or conditions, such as overuse and improper use of the legs.

Risk Factors

The following factors increase your chance of developing patellofemoral pain syndrome.

  • Malalignment of the knee joint caused by:
    • Rolling your feet outward during walking or running—can pull the kneecap out of line and cause painful rubbing of the kneecap against the bones of the knee
    • The kneecap being located too high or too low in the knee joint
    • Loose ligaments
    • Poorly-aligned bones
  • Weak or tight thigh muscles causing:
    • Inability to hold the kneecap in the correct position
    • The kneecap to rub against the femur during movement
  • Overuse and overloading the knee joint from:
    • High-impact sports or activities, such as running that result in pounding on the feet
    • Knock knees
    • Flat feet
    • High arches
    • Hip dysfunction
    • External rotation of the lower leg
  • Trauma, such as an automobile accident where the kneecap hits the dashboard


The first symptom is pain around or under the kneecap. The pain may first occur during high-impact activities. As the condition gets worse, the pain may be triggered by squatting, kneeling, or long periods of sitting. It is thought to be caused by the pressure on the kneecap while the leg is flexed. It is often increased by going down stairs or down hills. If you have knee or joint pain during activity, call your doctor.

Other symptoms may include:

  • Swelling of the knee
  • Popping or grinding sounds in the knee joint during activity
  • A snapping sensation in the knee


You will be asked about your symptoms and medical history. A physical exam will be done. Images may be taken of your knee.

Your doctor may refer you to a specialist. Orthopedic surgeons focus on bone and joint disorders.


The initial step is to rest the knee. High-impact activities should be switched for lower impact exercise. For example, choose swimming instead of running (except breaststroke). Your doctor may suggest that you apply ice to the kneecap after activity.

Longer-term treatment involves a number of different strategies, including:

Physical Therapy

A physical therapist will assess the injury. An exercise program will be created to help recovery and to strengthen the muscles around the knee. This includes the quadriceps muscles in the thigh as well as other muscles near the hip.


Over-the-counter medication may be advised to reduce pain.

External Devices

Some people find relief from knee braces or knee sleeves. These devices typically have a cutout in the kneecap area. They are designed to hold the kneecap in place during activity. Some are designed to hold the patella from going too far laterally.

Certain methods of taping the patella in position may also be helpful.

Special shoe inserts, called orthotics, may also be helpful. They work best when the condition is due to dysfunction in the foot, such as flat feet or excessive pronation.


In rare cases, people who do not respond to other forms of treatment may be recommended for surgery. This will be done to correct malalignment of the patella.


It may not be possible to totally prevent this condition. There are steps you can take to reduce your risk and avoid making the condition it worse, including:

  • Warm-up before exercising.
  • Vary the types of activities that you participate in. For example, rather than running or jogging every day, alternate between running and swimming.
  • Use appropriate footware for your sport.
  • Increase the amount and effort of activities slowly over time.
  • Use proper form and technique for any sport.
  • Take care of injuries right away. This includes getting first aid and resting the injury until it is healed before beginning an activity again.

Revision Information

  • Family Doctor—American Academy of Family Physicians

  • OrthoInfo—American Academy of Orthopaedic Surgeons

  • Canadian Orthopaedic Association

  • Health Canada

  • Juhn MS. Patellofemoral pain syndrome: a review and guidelines for treatment. Am Fam Physician. 1999; (60)7: 2012-2022.

  • Labella C. Patellofemoral pain syndrome: evaluation and treatment. Prim Care Clin Office Pract. 2004; 31: 977-1003.

  • Patellofemoral pain syndrome. Am Fam Physician. 1999 Nov 1;60(7):2019-2022. Available at: Accessed March 9, 2015.

  • Patellofemoral pain syndrome. EBSCO DynaMed website. Available at: Updated June 24, 2014. Accessed March 9, 2015.

  • 1/24/2011 DynaMed's Systematic Literature Surveillance Fukuda TY, Rossetto FM, Magalhães E, Bryk FF, Lucareli PR, de Almeida Aparecida Carvalho N. Short-term effects of hip abductors and lateral rotators strengthening in females with patellofemoral pain syndrome: a randomized controlled clinical trial. J Orthop Sports Phys Ther. 2010;40(11):736-742.