Femoral Acetabular Impingement


Femoral acetabular impingement (FAI) is a condition where the bones of the hip are abnormally shaped. Because they do not fit together perfectly, the hip bones rub against each other and cause damage to the joint.

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Patients can be seen by Texas Children's experts in Orthopedics.

Causes & Risk Factors

FAI occurs because the hip bones do not form normally during childhood. It is the deformity that leads to joint damage and pain when the hip bones are shaped abnormally.

Because athletically active people may work the hip joint more vigorously, they may begin to experience pain earlier than those who are less active. Exercise does not cause FAI, however.

Symptoms & Types

People with FAI usually have pain in the groin area, although the pain sometimes may be more toward the outside of the hip.

In FAI, bone spurs develop around the femoral head and/or along the hip socket. The bone overgrowth causes the hip bones to hit against each other, rather than to move smoothly. Over time, this can result in the tearing of the labrum (a fibrous ring of cartilage attached to the rim of a joint) and breakdown of articular cartilage (osteoarthritis).

There are three types of FAI: pincer, cam, and combined impingement.

Pincer. This type of impingement occurs because extra bone extends out over the normal rim of the hip socket. The labrum can be crushed under the prominent rim of the hip socket.

Cam. In cam impingement, the femoral head is not round and cannot rotate smoothly inside the hip socket. A bump forms on the edge of the femoral head that grinds the cartilage inside the hip socket.

Combined. Combined impingement means that both the pincer and cam types are present.

Diagnosis & Tests

A physical exam and x-rays are the first steps in a diagnosis. A physician may also ask for CT scans or MRI scans to make a diagnosis.

Treatment & Care

Nonsurgical treatment can include changes in activity levels, the use of non-steroidal anti-inflammatory medications and physical therapy.

Surgery may also be an option if non-surgical treatments don't relieve the pain.

References & Sources