Femoro-acetabular Impingement (FAI)

What is it?

The hip joint is comprised of the upper end of the thighbone, or femoral head and neck, and the hip socket or acetabulum. Cartilage, called labrum, lines the rim of the hip socket. Femoro-acetabular impingement (FAI) is a disease of the hip that results in labrum and cartilage injury.

Patients with FAI, have an abnormal relationship between the femur and the hip socket, resulting in increased hip contact forces with motion. This abnormal relationship is often because of the shape of the upper femur or the shape of the hip socket.

There are many theories for what may cause an abnormal relationship between the femur and hip socket. It can be due to a previous childhood disease such as Perthes, or SCFE (slipped capital femoral epiphysis) or the patient’s natural anatomy that results in injury once the hip is stressed in sports. Hip impingement is a common cause of hip osteoarthritis in young adults.

Why come to The Children’s Hospital for treatment of this condition? 

Our doctors routinely see and treat pediatric, adolescent and young adults with hip problems. Our team of experts at The Children’s Hospital and its affiliate, the University of Colorado, are specially trained in diagnosis and treatment of FAI, along with other hip disorders, such as dysplasia. The surgeons at Children’s and the University are nationally recognized and often participate in national teaching, research and study groups regarding hip disease.

Since this condition typically begins in adolescence and continues to affect patients into adult ages, it is important to evaluate patients affected with this condition into young adulthood. Therefore, we will evaluate and often treat patients into their young adult years (greater then 18 years of age). The Children’s Hospital works closely with the University of Colorado Hospital to ensure coordination of care as a patient grows older. Our surgeons perform evaluation and surgery at both centers to assure continuity of care.

What are the signs and symptoms?  

The symptoms of hip impingement and cartilage tears include pain and/or stiffness in the groin region in front of the hip. This pain is often worse after athletic activities that involve hip movement such as dance. Pain and stiffness may worsen during and after periods of sitting. Occasionally the pain can be on the side of the hip or in the buttocks. Symptoms such as catching or locking of the hip are also common.

Patients who have hip impingement may experience limits to hip motion, such as flexion and rotation.

How do you diagnose it? 

We examine a patient to see if they experience pain with hip motion, have a limited range of motion in the hip and have a history of common symptoms such as groin stiffness or pain. A special series of hip x-rays are analyzed for characteristics of hip impingement, such as a non-spherical upper femur or a mis-shaped hip socket.

Hip symptoms will be recreated with hip motion of flexion and rotation, in something known as the impingement test.

Magnetic resource imaging (MRI) of the hip will often be performed to confirm the diagnosis, look for other causes of pain, and analyze the stage of injury to the labrum and cartilage. 

How do we treat it? 

The first recommended treatment is physical therapy, along with modifying activities that cause pain. If the pain continues after a period of rest and therapy, surgery will be considered. The goal of surgery is to reshape the upper femur to decrease the bone impingement and to repair the labrum tear if required. This procedure is typically performed through a procedure known as a “surgical dislocation of the hip.” Surgeons at The Children’s Hospital have lots of experience with this treatment. They are often involved in teaching other surgeons the technique and results of the surgery.

Some patients with more limited hip injuries are candidates for hip arthroscopy. If surgery is recommended, your surgeon at The Children’s Hospital will thoroughly discuss the options depending on the characteristics specific to the patient.

Who gets it, and can it be prevented? 

It is difficult to prevent hip impingement from occurring. It is our goal to prevent hip cartilage damage from worsening and eventual hip arthritis. It is common in individuals that are involved in a sport or activity where the hip is placed in extremes of motion. Sports that can bring out symptoms of impingement are dance, swimming, track, basketball and volleyball. However, any sport could cause this in any individual.