Femoroacetabular Impingement (FAI)

Approximately 10-15% of adults have femoroacetabular impingement, making it exceptionally common.¹ To understand this condition, we need to review the anatomy of the hip joint. The acetabulum of the pelvic bone is connected to the head of the femur or thighbone with a ball and socket joint. For the two bones to move past each other smoothly and without pain, the ball and socket surfaces are covered in articular cartilage. The synovium, a thin lining over the joint, produces small amounts of fluid to lubricate the cartilage and allow smooth movement.

Causes

Femoroacetabular Impingement is caused by an irregularly formed hip joint. This can be from additional bone growth (bone spurs) to the pelvis (pincer impingement) and/or femoral head (cam impingement). These bone spurs create friction and damage healthy tissue, which can result in labral tears or osteoarthritis. Those who participate in aggressive physical activities like athletes, may notice symptoms more frequently. However, physical activity does not cause femoroacetabular impingement.

Symptoms

If you are experiencing hip pain, visiting a qualified orthopedic specialist early on is important. A proper diagnosis can ensure the right treatment plan going forward. The most common symptoms of femoroacetabular impingement include:

Pain in the groin area that can radiate into the outer thigh.
Activities that involve twisting or squatting cause sharp pain.
Stiffness and decreased range of motion.
Ambulation may be painful and cause limping.

Diagnosing

The diagnostic process begins with a physical examination. During the exam, your orthopedic surgeon will perform an impingement test. In this test, your knee is bent and brought up toward your chest; then, the leg is rotated inward. Pain indicates a positive impingement test. X-rays can show bone spurs, CT scans show the abnormalities in better detail, and an MRI can show tissue damage, such as in the case of a labral tear or cartilage breakdown.

Treatments

Unfortunately, there is no cure for femoroacetabular impingement, only treatment of the symptoms. You should visit a qualified orthopedic specialist if you experience prolonged or significant hip pain.

Conservative Treatment Options

Activity modification is the first step in symptom relief. Avoiding aggravating activities can reduce instances of pain.

Physical therapy, rest, elevation, and ice can reduce inflammation in the joint and protect it from further damage. Your orthopedic surgeon will create a customized physical therapy plan, including exercises that strengthen the muscles surrounding the joint.

Oral nonsteroidal anti-inflammatory medications (NSAIDs) such as ibuprofen or naproxen can reduce inflammation in the joint and improve range of motion.

Surgical Treatment

If nonsurgical treatment fails to offer sufficient relief, we may have to consider surgery. Often, femoroacetabular impingement can be treated with arthroscopy. Small incisions are made to allow for tiny instruments and a camera (scope). Bone spurs are shaved down, and repairs are made to the damaged tissues as needed. More significant repairs may require a larger open incision, and when FAI leads to osteoarthritis, patients may benefit from a total hip replacement.

Resource:

Lee WY, Kang C, Hwang DS, Jeon JH, Zheng L. Descriptive Epidemiology of Symptomatic Femoroacetabular Impingement in Young Athlete: Single Center Study. Hip Pelvis. 2016 Mar;28(1):29-34. doi: 10.5371/hp.2016.28.1.29. Epub 2016 Mar 31. PMID: 27536641; PMCID: PMC4972876.