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Femoroacetabular Impingement (FAI)

hip pain caused by FAI

Cam impingement FAI

Treatment of FAI varies, based on your symptoms, joint health and lifestyle. 

Our sports medicine doctors can work with you to decide on a treatment plan. Typically, you will first try physical therapy and modified activity. If this does not resolve your issues, you may discuss treatment options with a surgeon. We have surgeons with expertise in hip arthroscopy and the treatment of athletic hip injuries. Our expertise can help improve your chances of fully returning to sports.

What Is FAI?

The hip is a ball (femur) and socket (acetabulum) joint, which allows motion in nearly all directions. In hip impingement, or FAI, the ball and socket of the hip do not fit together correctly, resulting in abnormal mechanics and eventual joint damage. Long-standing, untreated FAI is a very common cause of hip osteoarthritis.

There are two types of FAI: 

  • Cam impingement, which occurs when the ball of the hip joint is not perfectly round
  • Pincer impingement, which occurs when the socket of the hip overhangs and impinges (presses) against the ball.

In both cases, the eventual result is labral tears, cartilage damage and hip pain. A Mayo Clinic study recently found that bone abnormalities were present in greater than 85 percent of patients with labral tears. This shows the close link between labral tears and FAI.

What are the symptoms of FAI?

People with FAI or hip impingement generally have deep pain in the groin and limited hip rotation. Pain is usually triggered by activity. It may also occur when the hip is bent, such as with prolonged sitting. Because the bone changes that occur in FAI often lead to labral tears, the symptoms of FAI and labral tears are very similar.

How is FAI diagnosed?

Femoral head reshaped for normal hip joint movement

Head of hip reshaped for normal hip movement.

FAI is usually diagnosed by a detailed examination by your sports medicine physician. Specialized x-rays are also necessary to evaluate the bone structure of the hip. A specialized MRI is used to diagnose labral tears, which often occur in people with FAI. In some patients, a hip injection may be considered to verify the diagnosis of FAI and labral tear and also to treat symptoms.

How is FAI surgically treated?

Surgery usually involves reshaping the head of the hip bone. This helps create a normal joint surface, improving symptoms and flexibility. 

Sports Medicine Appointments & Referrals


Sports Medicine Locations

UC San Diego Health offers expertise in sports medicine within family medicine, orthopedics, surgery and rehab. Not all services are available at all locations.

La Jolla



Scripps Ranch