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What is hip impingement?

The hip joint is a ball and socket formed by the femoral head (ball) at the top of the thigh bone and the acetabulum (socket), which is part of the pelvis. The labrum is a special layer of tissue around the acetabulum critical for proper function of the hip. The femoral head and acetabulum are covered with a thick layer of cartilage that allows for smooth motion between the two surfaces. In some people, the femoral head and the acetabulum may have an abnormal shape. This can lead to abnormal contact between the two structures and a condition known as femoroacetabular impingement (FAI) or hip impingement can develop. Because of the abnormal shape of the bones, over time, the labrum and the cartilage of the hip can be damaged, which can lead to the development of hip arthritis.

Types of hip impingement

There are several types of femoroacetabular impingement:

  • Cam impingement is when the femoral head does not have a normal round shape and may have more of an oval shape 
  • Pincer impingement results when the acetabulum is too deep or has extra bone in the front of the socket 
  • Combined Cam and Pincer impingement can often occur together

What are hip impingement symptoms?

Pain and stiffness are the most common symptoms caused by hip impingement. Patients may experience pain in various locations including the groin, the front of the thigh, the outside of the hip, and occasionally the buttocks. Some people may notice mechanical symptoms such as catching, locking, and snapping that can occur during activities. For some patients, the pain can occur with prolonged sitting, with participation in sports, or even with other normal activities of life.

What causes hip impingement?

There are several theories about the causes of hip impingement including:

  • Inheriting genes that cause the femoral head and acetabulum to grow abnormally 
  • Stress on the growing bones of high-level athletes can lead to the development of FAI

How is hip impingement diagnosed?

A thorough history and careful physical exam by our hip specialists are the first steps towards understanding the cause of hip pain. Special X-rays are necessary to help see the shape of the femoral head and acetabulum to identify any abnormalities that may be associated with hip impingement. A physical examination to diagnose the cause of hip pain often includes: 

  • Watching patients walk 
  • Evaluating the range of motion of the injured and normal hip 
  • Checking strength and neurologic function 
  • Performing special exam maneuvers to reproduce the pain 
  • Examining the knee, and spine when indicated 

In addition to X-rays, your health care provider may recommend an MRI scan to show the condition of the soft tissues around the hip, and in some circumstances, a CT scan may demonstrate the bony abnormalities in 3D views.

Request an appointment with a Mass General Brigham sports medicine specialist to learn more.

Hip impingement treatment

Modifying or avoiding activities that cause pain to help reduce inflammation and alleviate the symptoms is the first step in femoroacetabular impingement treatment. Physical therapy treatments may improve range of motion, strength, stability, and function. For some patients, there may be a benefit to a hip injection with cortisone or possibly an injection of your own platelets to help heal damaged tissues.

Surgery for hip impingement

If a nonsurgical approach to hip impingement treatment doesn't alleviate symptoms, your hip specialist may recommend minimally invasive arthroscopic surgery to repair the damaged tissue and correct bone abnormalities around the hip.

Recovering from hip impingement surgery

The recovery time following arthroscopic surgery for hip impingement is typically about six months as patients need crutches for 3-6 weeks, followed by physical therapy exercises and treatments for several months. It's important not to overstress the joint by doing too much too soon.

Preventing hip impingement

Genetic bone conditions cannot be prevented but limiting repetitive twisting and squatting can help stave off hip issues. Strength training and stretches can improve hip function if you are prone to experiencing hip pain.


Rest, activity modification, and medication can sometimes improve the painful symptoms of hip impingement, but arthroscopic surgery is often needed to repair soft tissue damage and fix bone issues if patients have persistent pain.

Any movement of the hip can cause pain, including walking. Proper stretching and warmup can help limit pain when walking.

Proper X-ray views may show the abnormal bone shapes (cam and pincer lesions) associated with FAI.

No, arthritis and hip impingement are different issues, but patients with hip pain and X-rays that show FAI are at risk of developing hip arthritis.

Physical therapy and stretching can be helpful for some patients suffering from femoroacetabular impingement symptoms.

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