Hip Impingement (Femoroacetabular Impingement)

 

What is hip impingement?

Hip impingement, also called femoroacetabular impingement (FAI), happens when the ball and socket of the hip joint do not fit together normally. This can cause the bones to rub against each other during movement, leading to hip or groin pain. Over time, this repeated contact between the bones can damage the cartilage or labrum (a ring of tissue around the hip socket) and can contribute to changes in the hip joint. Hip impingement can occur with or without osteoarthritis. 

Hip impingement can affect people of all ages, including teens and young adults.

What causes hip impingement?

Hip impingement can develop for several reasons:

Shape of the hip joint and development: Hip impingement may occur when the ball or socket of the hip joint has an abnormal shape. The top of the thigh bone (femoral head) or the area just below it (femoral neck) may be misshapen, or the hip socket may cover too much of the femoral head. Some people are born with these differences, while others develop them as they grow.                     

Repetitive activity or injury: Repetitive activities that move the hip beyond the normal range of motion may contribute to hip impingement. This can occur in athletes who participate in football, baseball, soccer, tennis, hockey, lacrosse, dance and golf. An injury may also cause symptoms of hip impingement.

Childhood hip conditions: Certain conditions, including Perthes disease and slipped capital femoral epiphysis (SCFE), may also lead to hip impingement.

What are the types of hip impingement?

Cam impingement

Cam impingement occurs when the ball-shaped top of the thigh bone (femoral head) is not perfectly round. This can prevent the ball from moving smoothly within the hip socket and cause it to rub against the edge of the socket.

Pincer impingement

Pincer impingement occurs when the hip socket (acetabulum) covers too much of the femoral head. When the hip bends, the thigh bone can come into contact with the edge of the socket.

Combined impingement

Combined impingement occurs when a person as both cam and pincer impingement in the same hip. 

What are the symptoms of hip impingement?

In the early stages, hip impingement may cause no symptoms, or symptoms may be mild and hard to pinpoint. Common symptoms include:

• Stiffness in the thigh, hip or groin.
• Difficulty bending the hip past a 90-degree angle.
• Groin pain after bending the hip, such as during running, jumping or sitting for long periods.
• Pain in the hip, groin or lower back during activity or rest

How is hip impingement diagnosed?

Our WashU Medicine hip and knee orthopedic surgeons offer comprehensive diagnostic services for hip impingement. Diagnosis begins with a complete medical history and a physical examination. During the physical exam, your doctor will check your hip's the range of motion and look for signs of impingement.

Additional imaging tests may be needed, including:

• X-rays: Provide images of the bones and structure of the hip joint.
• Magnetic resonance imaging (MRI): Provides detailed images of the hip joint, including soft tissues such as the cartilage and labrum.
• Computed tomography (CT) scan: Combines images taken from different angles to create a detailed 3D image of the hip. This can help your doctor better understand the shape and structure of the joint. 

How is hip impingement treated?

Nonsurgical treatment for hip impingement

We will discuss appropriate treatment options with you. Some patients are able to successfully manage hip impingement with conservative therapies, including:

• Reducing certain types of physical activity.
• Physical therapy.
• Pain management.
• Injections.

Surgical treatment for hip impingement

For some patients, surgery may be recommended to treat hip impingement. Surgery may be minimally invasive (arthroscopic) or open, depending on the type and severity of the hip deformity.

Arthroscopic surgery is the most common and can correct most types of hip impingement. More severe or complex hip impingement deformities may require open surgery to fully correct the shape of the joint. In some cases, an osteotomy may be performed to cut and realign the bone. This can improve the position of the hip joint and reduce or eliminate abnormal contact between the bones.

An abnormally shaped femoral head or hip socket may also be reshaped through osteoplasty or debridement. During these procedures, the surgeon reshapes the ball or socket to create a smoother fit and improve movement of the hip joint. 

Both arthroscopic and open procedures can provide excellent clinical results. After surgery, patients typically complete a course of physical therapy that can last three to four months.

In some cases, especially when there is significant arthritis damage to the hip joint, total hip replacement may be recommended.

How do I know what hip impingement treatment is right for me? 

The right treatment depends on several factors, including the type and severity of your condition, amount of arthritis in the joint, your age and activity level and your treatment goals and preferences. We will help you understand the risks and benefits of each option and determine which treatment is right for you.

Why choose WashU Medicine Orthopedics for hip impingement treatment?

Our fellowship-trained orthopedic surgeons have expertise in diagnosing and treating hip impingement and other complex hip conditions in teens and adults. Our hip preservation specialists use both nonsurgical and surgical treatments, with a focus on preserving the natural hip joint, bone and function whenever possible. Our goal is to reduce pain, improve hip function and help you return to the activities you enjoy.

For teens and young adults, our Adolescent and Young Adult Hip Disorders Center provides specialized care for hip impingement and other hip conditions. Our orthopedic surgeons work with specialists in pediatric orthopedics, physical medicine and rehabilitation, and physical therapy to provide a complete evaluation and personalized treatment plan focused on preserving the natural hip joint.

Frequently asked questions (FAQs)

Who is affected by hip impingement?

Hip impingement commonly affects active adolescents and young adults. 

Can I exercise or play sports with hip impingement? 

Many people with hip impingement can continue to exercise and stay active, but you may need to modify activities that cause hip pain. Activities that put more stress on the hip may make symptoms worse. Talk with your doctor about which activities are safe for you and when you can return to sports.

What happens if hip impingement is left untreated?

If hip impingement is not treated, it may lead to cartilage damage and osteoarthritis.

How successful is surgery for hip impingement?

About 80% of patients have successful outcomes in the short term after surgery for hip impingement.