Hip Impingement (Femoroacetabular Impingement or FAI)

Hip impingement is painful pinching that happens when the bones in your hip don’t fit together like they should. Healthcare providers also call it femoroacetabular impingement or FAI.

FAI is painful. It can make it hard to walk or move. You might feel stiff or sore all the time on one side. Over time, the impingement can damage the cartilage that cushions your hip joint.

Visit a healthcare provider if you’re experiencing hip pain, stiffness or other symptoms that don’t get better in a week or two.

Types of FAI

Healthcare providers classify hip impingement as one of three types. Each type is based on why your hip doesn’t fit together like it should:

• Cam impingement: This happens when extra bone grows on the top of your thigh bone.
• Pincer impingement: This is extra bony growth in your hip socket.
• Combined impingement: This is when you have cam and pincer impingement at the same time.

Symptoms of hip impingement

The most common femoroacetabular impingement symptoms include:

• Hip pain
• Stiffness
• Limping or trouble moving

Some people with FAI never experience symptoms. You might notice worsening symptoms over time. This is especially true if impingement damages the cartilage in your hip joint.

What does femoroacetabular impingement feel like?

Hip impingement usually feels like a constant, dull ache in your hip. The pain might spread to your:

• Groin
• Butt
• Thighs

It might feel like there’s a bruise deep inside your body that someone is constantly pressing on.

FAI pain typically gets worse during physical activities. You may notice it more during motions like:

• Squatting
• Lunging
• Jumping

Lying on your side or sitting still for a long time can also make the pain worse. These activities or positions can make the pain feel sharp or stabbing.

Femoroacetabular impingement causes

FAI happens when the bones in your hip joint rub, catch or put extra pressure on each other. It’s usually because of a bone spur on your thigh bone or in your hip socket. Most people with unusually shaped joints are born with them. Bone spurs can develop throughout your life.

Risk factors

Anyone can be born with or develop hip impingement. Males are more likely to have cam impingement. Females are more likely to have pincer or combined impingement.

Athletes are more likely to experience symptoms. Especially if they play sports that put lots of pressure on their hips. This doesn’t mean that playing sports makes you more likely to develop impingement. But athletes are more likely to notice symptoms. That’s because they use their hips more often and more intensely than most people.

Complications of FAI

Hip impingement can damage your hip joint if it’s not treated. The most common complications include:

• Worsening symptoms: This can make it harder to move or use your hip.
• Labral tears: The extra pressure and friction from FAI can gouge the cartilage lining in your hip socket. This can lead to a tear.
• Osteoarthritis: Impingement increases your risk of arthritis in that hip.

How doctors diagnose femoroacetabular impingement

A healthcare provider will diagnose FAI with a physical exam and imaging tests. Tell your provider when you first noticed symptoms. Let them know if any movements, activities or positions make the symptoms better or worse.

Your provider will use imaging tests to take pictures of your hip. These tests may include:

• X-ray
• MRI
• CT scan

Your provider may inject a small amount of local anesthetic into your hip to numb it. The medication might temporarily relieve symptoms. This can be a sign you have FAI. They may use other medications to manage hip impingement. But this is usually a good way to help diagnose it.

Hip impingement test

An FAI test will help your provider check for hip impingement. You’ll lie on your back, and your provider will lift your leg up toward your chest. Then, you’ll bend your knee so your leg forms an L shape. Your provider will twist your upper leg in, toward the center of your body.

These positions let your provider put light pressure in places you might have FAI. You might have hip impingement if you feel pain during these movements. The test may be uncomfortable. But it’s safe. Tell your provider if you feel any severe pain during the test.

What are FAI treatments?

Common femoroacetabular impingement treatments include:

• NSAIDs: Over-the-counter NSAIDs reduce inflammation and relieve pain.
• Corticosteroids: These are prescription anti-inflammatory medications. Your provider may give you a cortisone shot directly into your hip joint.
• Physical therapy: Physical therapy will help you strengthen the muscles around your hip. This can relieve pressure on your joint. It will also improve your mobility.
• Activity modification: You might need to avoid certain movements that make the pain worse. You’ll be able to stay active. But you might have to change how you exercise or train.
• Surgery: Your provider will suggest surgery if you have severe symptoms that affect your quality of life. You might need surgery if other treatments don’t work or if you have a hip labral tear. Hip arthroscopy is the most common surgery to repair hip impingement. Your surgeon will tell you what to expect.

When should I see my healthcare provider?

Visit a healthcare provider if you’re experiencing FAI symptoms for more than a few weeks. Tell your provider if the symptoms make it hard to move or use your hip.

Talk to your provider if treatments like NSAIDs or physical therapy aren’t working as well as they used to.

Will hip impingement go away?

FAI won’t go away unless you have surgery to correct the shape of your hip. But most people can manage symptoms with other treatments.

Talk to your provider about which treatments are right for you. Ask them when you should consider surgery.

Surgery to repair femoroacetabular impingement has a very high success rate. Many people have no long-term side effects. You might have to avoid or modify certain exercises or movements. But you should still be able to stay active and play sports.