What is femoroacetabular impingement, or FAI?

Two bones in the hip rub against each other due to an abnormally shaped hip joint. The pressure causes friction both at the top of the femur and at the acetabulum-the part of the pelvis from which it protrudes-and can limit motion and be painful.

Left untreated, FAI damages the cartilage cushion in the hip. Inevitably, this damage causes arthritis, or painful joint wear. Some people must have surgery to fix the damage. FAI is also known as hip impingement.

What causes femoroacetabular impingement (FAI)?

The hip joint is a ball-and-socket type between the femur and the pelvis. All those patients who suffer from FAI have either an abnormality in the ball or the socket (groove in the hip bone). Such abnormalities cause friction during movement and damage the surrounding cartilage and labrum, which is the cartilage lining the hip socket.

The abnormalities associated with FAI are usually present since birth, although it often develop later, especially during adolescence. Doctors classify FAI into one of the three categories depending upon the cause:

Cam: This kind is the outcome of a bone growth near the femur's head. Physical exertion may occasionally be the source of this development.
Pincer: This form of FAI is due to bone overgrowth on the rim of the acetabulum and primarily occurs in a growing child.
Combined: Both forms of cam and pincer combine to form FAI

FAI may result in a person who is highly active in life to experience pain sooner than those who are not. Most importantly, exercise does not cause FAI.

What are the signs of femoroacetabular impingement (FAI)?

In some cases, the individuals with FAI do not have any symptoms. The signs and symptoms of the disease start to present as the damage in the hip worsens. Below are the manifestations of FAI and the symptoms developed by the patients with the disease:

Hip pain at the side that worsens with activities or long periods of sitting
Limping
Stiffness of the hip

Your doctor will ask you about your family history and your activity level. To confirm the diagnosis of FAI, your physician may use the following:

Imaging tests include X-rays and MRIs, which help a doctor view abnormalities and signs of damage within the hip joint.
Impingement test: The doctor will hold your knee up toward your chest and move it so that the femoral head impinges against the acetabulum. This movement reproduces the same type of pain in a patient with FAI.
Local anesthetic: Doctors can diagnosis FAI by injecting numbing medicine into the joint. The doc can then see if the injection helps to relieve the pain.
Physical exam: Your doctor can assess the hip joint's functionality with a physical examination that measures your walking style, muscular strength, and range of motion.

What are the treatments for femoroacetabular impingement (FAI)?

This treatment depends on the individual and the extent of damage. Some treatments for FAI include the following:

Corticosteroids decrease inflammation (swelling) inside and outside the hip joint. Doctors typically administer this treatment via injection.
Nonsteroidal anti-inflammatory drugs (NSAIDs) reduce inflammation and are most commonly taken orally in pill form.
Physical therapy: Certain exercises will help strengthen the joint and improve mobility.
Rest: Less activity minimizes the friction present in the hip joint.

Surgery: Doctors may take several surgical routes to repair the joint.

Arthroscopic hip surgery is a highly minimally invasive procedure in which a doctor repairs or removes damaged bone or cartilage.
Traditional hip surgery: In worse situations, doctors carry out an open operation where a wider incision is made to repair the damage.

Complications of Femoroacetabular impingement (FAI)

Some individuals with FAI who do not get treated degenerate into hip osteoarthritis, which can be described as the breakdown of cartilage surrounding the hip. Such complications may cause severe pain and movability. How do you prevent femoroacetabular impingement (FAI)?

Most cases of FAI cannot be prevented. Early treatment is therefore essential to prevent the damage that FAI can cause to the hip from deteriorating further.

Who is at risk for developing femoroacetabular impingement (FAI)?

For some cases, athletes or those with active lifestyles are often at risk of developing FAI.

Doctors often are successful in treating many cases of FAI. Many who have treatment for FAI lead active lives with little to no discomfort in the hip.