Femoracetabular Impingement (FAI)

Diagnosis & Treatment of Hip Pain

It’s a long and complicated-sounding name, but the premise behind femoroacetabular impingement (FAI) is pretty simple: FAI occurs when one or both bones that comprise the hip joint grow abnormally, resulting in a poor “fit” inside the joint. In a healthy hip, the ball and socket portions of the joint fit snugly, but still allow ample room for joint movement and function without friction. In FAI, the irregular shape of one or both bones increases friction and bumping inside the joint, and that leads to pain and other symptoms that can take a significant toll on your mobility and overall quality of life. Without treatment of hip pain, repetitive bumping inside the joint can lead to inflammation, arthritis and pain; substantially increasing the likelihood that you’ll need a joint replacement surgery in the future. (The name “femoroacetabular impingement” is from the names of the two bones that form the joint – the femur or thigh bone, which forms the ball portion of the joint, and the acetabulum, which forms the socket portion of the joint.)

What causes femoroacetabular impingement?

FAI develops when bony growths called bone spurs form along the edge of the bones that form the hip joint. These bones “catch” and cause impingement between the femur and the acetabulum, interfering with normal, smooth movement. Bone spurs can form as a part of normal bone growth and development or following a traumatic joint injury.

There are three types of FAI:

• Cam impingement is caused by irregularities in the shape of the femoral head (the ball portion of the joint) which prevents the ball from moving smoothly in the socket. These irregularities grind against the socket, damaging the cartilage that lines the joint.
• Pincer impingement occurs when bony growths form on the rim of the socket part of the joint. These growths can wind up damaging the cartilage ring (the labrum) that surrounds the socket and holds the ball portion in place.
• Combined impingement involves irregular bone growth on both parts of the hip joint.

If you have FAI, you may have symptoms of pain and joint stiffness that can result in a limp or other gait problems. Discomfort can range from a dull ache to a stabbing, sharp pain, and it can occur in the groin or toward the outer portion of the hip. Turning or pivoting the hip can cause symptoms to become worse.

How is FAI diagnosed and treated?

FAI is diagnosed with a physical exam and a review of your symptoms, along with imaging tests like MRIs, X-rays or CT scans. During your exam, Dr. Van Thiel may perform what’s known as an “impingement test,” a simple passive exercise where your hip is raised and gently pivoted or rotated while you lie on your back. The aim of the test is to see if the movements cause symptoms to occur; if they do, it’s more likely your symptoms are due to impingement.

Once the diagnosis of FAI is confirmed, mild symptoms may first be treated with medication and physical therapy. More severe symptoms probably require surgery to correct the source of the impingement and repair any damage to the labrum and the cartilage. In most cases, FAI can be treated with a minimally-invasive surgery called hip arthroscopy. In this procedure, a special instrument called an arthroscope is inserted into the joint through a small incision. The scope includes a small camera that enables Dr. Van Thiel to view the joint without the need for a large incision. Another small incision will be made to admit the surgical instruments used in hip arthroscopy.

During a hip arthroscopy procedure, bony overgrowths will be removed from the acetabulum and the femoral head may be shaved and smoothed as well, depending on the type of FAI that’s present. Following surgery, you’ll need to wear a brace and use crutches for several weeks, physical therapy during the weeks and months that follow will help restore normal, pain-free range of motion in the hip. Treatment of hip pain can seem extensive, but greater mobility and less discomfort is possible.

Find out what is causing your hip pain.

Although it’s not as common as knee pain, hip pain can have effects that are just as serious. If you’re having hip pain, stiffness or other symptoms, call OrthoIllinois at 815-398-9491 and schedule a consultation with Dr. Geoffrey Van Thiel today.