Femoroacetabular (hip) Impingement (FAI)

Overview

Hip impingement, also known as femoroacetabular impingement (FAI), is a mechanical and structural hip condition. FAI can occur when increased friction prevents the smooth movement of the ball in the hip socket.

For people under the age of 40, hip impingement can be a cause of osteoarthritis of the hip.

Symptoms of hip impingement are often not noticeable for the first few years, but as your condition progresses, symptoms may worsen.

The most common symptom of hip impingement is a pain in the groin when flexing the hip or walking.

In many patients, resting, nonsteroidal anti-inflammatory medications, and physical therapy can alleviate symptoms. 

Hip impingement causes

The two leading causes for hip impingement include:

• Cam impingement: When the ball of your hip is deformed at the top of the femur.
• Pincer impingement: When the socket of your hip is deformed.

Cam and Pincer impingement can occur at the same time resulting in combined impingement.

Other conditions, such as Legg-Calve-Perthes disease, slipped capital femoral epiphysis, or Coxa vara, can cause hip impingement.

Hip impingement symptoms

Hip impingement is often painless in the early stages; therefore, many people do not experience symptoms until the condition progresses.

When symptoms develop, the most common symptoms include:

• During the early stages, you may only notice the pain when your hip is overused. Later, you may feel pain during day to day activities such as walking up a hill.
• Pain at night
• Limping
• Stiffness

Sometimes the pain is dull and can be felt in the groin or outside of the hip. Sharp pain can occur when twisting, squatting, or turning.

Hip impingement complications

If left untreated, hip impingement can lead to osteoarthritis.

Hip impingement risk factors

• Trauma to the hip
• Bone structure abnormalities in the hip
• Repetitive hip flexion
• Some sports may also put you at risk of developing hip impingement, including:
  • Football
  • Hockey
  • Weightlifting
  • Running

Hip impingement prevention

Some precautionary measures you can take to reduce your risk of developing hip impingement include:

• Rest
• Modify activities to avoid heavy stress on the hips
• Strengthen the muscles around the hip

Hip impingement diagnosis

Your doctor will perform a physical examination to diagnose hip impingement. During your physical exam, your doctor will review your full medical history to determine when your symptoms began and potential activities that might have caused the tears or strain.

Your doctor may also order an X-ray, MRI, or CT scan to rule out other possible conditions.

Hip impingement treatment

As first-line therapy, your doctor will prescribe rest, ice, exercise modification, and nonsteroidal anti-inflammatory medications.

If conservative treatments are not effectively relieving your symptoms, your doctor may recommend hip impingement surgery. Hip impingement surgery may be performed arthroscopically so that the recovery time is shorter. The earlier you have surgery, the more likely you are to have a full recovery.

As a last resort option, hip replacement may be necessary to treat hip impingement.

When should I seek care?

If you are experiencing symptoms related to hip impingement, contact your doctor to make an appointment.

Next Steps

Your doctor will recommend the most appropriate treatment for your case. Depending on the severity of your condition, your doctor may prescribe rest and nonsteroidal anti-inflammatory medications. If medications are not relieving your symptoms, your doctor may recommend surgery.

If you participate in activities that put stress on your hips, try exercises that strengthen your hips, and improve your flexibility.

Follow your doctor’s recommended treatment plan and schedule an appointment if your symptoms change or worsen.