Femoroacetabular Impingement (FAI)

What is femoroacetabular impingement (FAI)?

The hip joint has a femoral head which is a ball attached at the top of the femur (thigh bone) and an acetabulum which is a socket cup in the pelvic bone. When a normal hip joint moves, the femoral head and acetabulum that are covered in cartilage glide past each other smoothly. The hip joint depends on the spherical shape of the femur head for normal motion. The roundness of the femoral head and the amount of coverage of the acetabulum play a critical role in normal motion. Disturbances in the shape of the femoral head or the coverage of the acetabulum can lead to limitations in normal motion—a condition called femoroacetabular impingement (FAI).

The acetabulum is surrounded by cartilage—the labrum—which forms a seal around the socket and helps to stabilize the joint. Femoroacetabular impingement can cause a labral tear in the hip joint. It is also associated with the early onset of osteoarthritis because of repeated damage to the hip joint cartilage.

FAI can lead to significant discomfort and activity limitations, and it can be debilitating. The common symptoms from femoroacetabular impingement include pain and stiffness (loss of joint movement). Pain typically occurs in the groin but can be non-specific in the hip region. Pain is also activity-related, particularly during deep flexion (squatting), twisting and turning. Because of the pain, patients may be forced to give up certain activities.

What causes femoroacetabular impingement (FAI)?

There are multiple causes for femoroacetabular impingement. Conditions that make the shape of the hip joint irregular potentially can cause the condition. Common childhood hip diseases that can cause FAI are hip dysplasia (abnormal formation of the hip joint), Perthes disease (disruption of blood supply to femoral head), or slipped capital femoral epiphysis (growth plate slippage in femoral head). Other causes of femoroacetabular impingement include infection and trauma.

How common is femoroacetabular impingement (FAI)?

The percentage of people affected by femoroacetabular impingement is unknown because not all patients have symptoms. FAI can affect both males and females. The symptoms of the condition are more commonly seen in younger individuals because they tend to have higher activity levels. It is being increasingly recognized as a cause for increased risk for early arthritis and joint replacement.

How is femoroacetabular impingement (FAI) diagnosed?

If femoroacetabular impingement is suspected, a doctor will typically start with a detailed history and thorough physical examination. If the history and physical examination correlate to the diagnosis of FAI, the doctor will proceed to obtain X-ray images to confirm the diagnosis. X-ray is the first line option to assess the shape of the hip joint. If a labral tear or joint cartilage damage is suspected because of FAI, an MRI (magnetic resonance imaging) scan with or without contrast (dye) can be used. MRI with contrast is better to assess the labral tear than the MRI without contrast, but some patients may be allergic to the contrast agent.

What are the treatment options for femoroacetabular impingement (FAI)?

The treatment options for femoroacetabular impingement consist of both non-surgical and surgical methods. Non-surgical treatment is the first line option because it is less invasive and easy to obtain. Non-surgical treatments include but are not limited to pain relief (anti-inflammatories), activity modification (avoiding activities that aggravate the pain) and physical therapy. Steroid injections into the hip joint can help provide pain relief.

Surgical treatments of FAI include reshaping the hip joint and hip joint replacement. Reshaping the joint by removing impinging bone spurs can be done either through arthroscopy (keyhole surgery) or open surgery depending on the location and size of the impinging bone spurs. In arthroscopic surgery, the surgeon makes a smaller incision, and then inserts a small camera into the hip joint. The camera shows pictures on a video monitor, and these help guide the surgeon. Arthroscopic surgery often is less painful, and it shortens the time necessary to recover and return to a normal activity level. Repositioning of the acetabulum can also be done in many cases. Joint replacement surgery is typically reserved for patients whose hip joints are already arthritic.

Why choose the International Center for Limb Lengthening for treatment of femoroacetabular impingement (FAI)?

Doctors who treat femoroacetabular impingement (FAI)