Understanding Femoroacetabular Impingement (FAI)
The hip is often called a ball-and-socket joint. The top part of the femur or thighbone is the ball. It fits into the socket called the acetabulum. Normally, soft tissue called cartilage covers the ball and socket of the hip. This helps the bones move smoothly against each other during movement. The cartilage lining the hip socket is called the labrum. With excess bone growth, the bones rub against each other, causing pain. This is femoroacetabular impingement or FAI. FAI can also cause the labrum to tear.
How to say it
FEHM-er-oh-as-uh-TAB-yoo-ler
ihm-PIHNJ-mihnt
Types of FAI
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Pincer. Extra bone grows over the rim of the acetabulum.
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Cam. Bone grows on the femoral head and can’t rotate smoothly
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Mixed. Some people have a combination of both.
What causes FAI?
FAI develops when there is a deformity of the ball of the joint or the socket. The cause it not exactly known. But studies suggest that genetics may contribute to this deformity. When hip bones don’t form normally as a child grows, it can result in FAI. Evidence also suggests that teens who take part in high-intensity sports or are athletic are more likely to have FAI.
Symptoms of FAI
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Pain, often in the groin. It occurs when flexing the hips especially when sitting for long periods, twisting or squatting, or walking. Pain may be a dull ache or sharp and stabbing.
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Pain may occur toward the outside of the hip
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Pain may radiate to the thigh
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Decreased range-of-motion
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Joint stiffness
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Clicking, popping, and catching of the hip
Some people have no symptoms and FAI may be found when they are checked for another condition.
Diagnosis
If you have hip pain, your healthcare provider will do a physical exam and check your form when walking or running. This is called gait assessment. You may also be asked to balance on 1 leg and demonstrate your hip’s range of motion. You may also have X-rays and other imaging (such as MRI or CT scan.) You may also have an anesthetic shot (injection). This is a numbing medicine injected into the joint.
Treatment for FAI
Treatment for FAI includes
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Adapting your lifestyle and activities
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Physical therapy
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Surgery to remove the excess bone and possibly to repair a torn labrum
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Pain and anti-inflammatory medicines
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Cortisone shot to reduce inflammation
Possible complications of FAI
Complications of FAI include a future risk of developing arthritis, arthritic pain, and need for a hip replacement, regardless of treatment.
When to call your healthcare provider