Hip impingement, also known as Femoroacetabular Impingement (FAI), is a condition of the hip where the hip is malformed upon birth. The hip is a ball and socket joint. In a normal hip, the femoral head (ball), which is the rounded top of the thigh bone, fits into the acetabulum (socket), in the lower pelvis. Cartilage lines the bones, provides a smooth gliding surface and helps keep the femoral head in place.
What is hip impingement?
In hip impingement, the femoral head or acetabulum are malformed, causing friction that can damage the joint over time. According to Dr. Vladimir Alexander, Founding Partner of Alexander Orthopaedics, “Hip impingement exists on a continuum of congenital dysplasia of the hip. There’s no black and white, meaning some hips aren’t perfect and some hips are very abnormal. If you're not very abnormal, you may have hip impingement, where the hip is slightly misshapen from normal.”
Types of hip impingement
There are three types of hip impingement:
- Cam: The femoral head of the hip joint is not round and it cannot rotate smoothly inside the acetabulum.
- Pincir: Bone overgrowth causes the acetabulum to overextend over the femoral head.
- Combined: While most people experience a single type of hip impingement, it’s possible to experience combined impingement in which both conditions are developed in the same hip joint.
What does hip impingement feel like?
Hip impingement typically feels like pain in the deep buttock, pain in the groin, and pain on the outside of the thigh, which are all typical of any hip pain.
- Symptoms for hip impingement include:
- Pain after sitting for a long time
- Pain while rotating the hip
- Pain while getting into or out of a chair or a car
- Stiffness in the groin, thigh or hip
- Pain or aching after running or jumping
- Pain while walking uphill
What causes hip impingement?
Hip impingement is typically present from birth. However, it is possible to develop an abnormal shape over time, as is sometimes the case for young athletes who do sports involving lots of squatting and twisting of the hip.
According to Dr. Alexander, “The age presentation of these patients is generally younger, so it can happen somewhere between your 20s and your 50s.”
Hip impingement complications
Hip impingement & osteoarthritis
When the hip’s ball and socket do not fit together properly, this can cause the articular cartilage to undergo friction, wearing away at the cartilage. The degeneration of this cartilage is a key characteristic of hip osteoarthritis. In fact, both forms of hip impingement can lead to hip osteoarthritis, according to an article published in The Bone & Joint Journal.
How can this be prevented? Another study, published in Clinical Orthopaedics and Related Research, proposed that early surgical intervention for treatment of hip impingement can decelerate the degenerative process for young people.
Hip impingement & torn labrum
In addition to damaging the articular cartilage, hip impingement injures the labrum. According to Dr. Alexander, “Hip impingement can lead to tearing of the lining of the hip called the labrum, so a labral tear in the hip can be caused by hip impingement.” A hip labral tear can be repaired surgically.
How is hip impingement diagnosed?
The first step in diagnosing hip impingement is a medical history exam, in which doctors ask about where the pain is located, when did symptoms begin and how severe the symptoms are. The doctor may also perform a physical exam to assess the hip’s range of motion. Part of this exam may be the impingement test. In this test, the doctor brings the knee towards the chest and rotates it inward. If this recreates the existing hip pain, it’s indicative of impingement.
After the medical history and physical exam, you may need imaging tests
to confirm the presence of joint damage or bone spurs caused by impingement.
- X-rays can demonstrate whether the hip has abnormally shaped bones, as well as signs of arthritis.
- CT scans provide more detail than X-rays and can display the exact abnormal shape.
- MRI scans show soft tissue, which can help the doctor identify damage to the labrum and cartilage.
What is the treatment for hip impingement?
Acetaminophen and nonsteroidal anti-inflammatory drugs (NSAIDs), including ibuprofen, naproxen, and aspirin, can help limit aching pain and discomfort. While taking these medications can help alleviate aching and stiffness, making movement easier, taking them long-term can cause various side effects.
Some activities that involve repeated rotation of the hip, such as ballet, baseball, or golf, can increase friction between the ball and socket and cause pain in the hip or groin area. Avoiding these activities can help you reduce pain and stiffness.
According to the American Academy of Family Physicians (AAFP), physical therapy should aim to improve “hip muscle flexibility and strength, posture, and other muscle or joint deficits identified in the physical examination.” Our experienced physical therapists can help relieve your hip impingement symptoms by identifying movements you should avoid and building up strength to improve your hip joint function.
If activity modification, physical therapy, and medications do not ease symptoms, your doctor can inject corticosteroids into the hip joint, which reduce inflammation and provide pain relief.
If symptoms persist, then a hip arthroscopy can be performed to repair or remove injured tissue, alleviate impingement and prevent or delay osteoarthritis, according to the AAFP. A hip arthroscopy allows surgeons to access the hip joint through very small incisions, which minimizes the potential damage to muscle and soft tissue.
Labral tears can also be repaired during a hip arthroscopy, according to Dr. Alexander. “We go into the hip arthroscopically, we clean up the labrum or stitch the labrum back together depending one what the findings are, and we reshape the socket and/or the head of the femur.”
After the hip is treated arthroscopically, patients have to limit weight-bearing for 2-4 weeks, and receive physical therapy after that. People typically recover from a hip arthroscopy 8-12 weeks after surgery.
What is the hip impingement recovery process?
If you are experiencing pain and stiffness that interfere with your daily life, we can help. Our highly experienced physicians and physical therapists will work with you to create a personalized treatment plan from diagnosis to recovery.