What is a hip impingement?
Femoroacetabular impingement (FAI), also known as hip impingement, is a mechanical or structural disorder of the hip. It can occur in people of all ages, including adolescents and young adults. The hip is a “ball and socket” joint: the rounded top of thigh bone (femoral head) “plugs into” the hip socket (acetabulum) in such a way that the femoral head can move smoothly within the socket. The joint is lined with a thin layer of smooth cartilage that cushions and protects the bones, preventing them from rubbing or grinding against each other. The rim of the hip socket is lined with a special ring of cartilage called the labrum that further helps to secure the femoral head in place inside the hip socket. The labrum functions as an “O-ring” or “gasket” for the hip, suction sealing the ball inside the socket. Hip impingement occurs when something prevents the smooth, painless, and free movement of the ball-and-socket joint. Dr. Austin Chen, a hip specialist serving the greater Boulder, Colorado communities, specializes in impingement of the hip.
What are the causes of hip impingement?
There are two main causes of hip impingement:
1. Cam Impingement – a deformity of the ball at the top of the femur. If the head is not shaped normally, the abnormal, or “non-rounded” part of the head can pinch against the rim of the socket and labrum when the hip is moved in certain ways. This may occur during activities such as tying your shoes, or getting into or out of a car.
2. Pincer Impingement – a deformity of the socket. If the rim of the socket (called the acetabulum) sticks out too far, the area of the thigh bone (femur) just below the ball, called the neck of the femur, may bump into the rim of the socket during normal hip movement.
In most cases, there is a problem with both the ball and the socket. Other problems that can cause hip impingement include conditions such as:
- Legg-Calve-Perthes disease, a disease in which the ball part of the hip joint doesn’t get enough blood during growth and development causing a misshappen femoral head or even femoral head death.
- Slipped capital femoral epiphysis, a separation or “slip” of the ball from the thigh bone at the upper growing end (growth plate) of the bone in adolescents. It is more common in children with obesity or endocrine abnormalities.
- Coxa vara, an unusual condition in which the thigh bone and ball do not grow at the same pace in children. This discrepancy leads to deformity of the hip joint.
What are the symptoms of hip impingement?
Patients often complain of pain in the groin after prolonged sitting or walking. Many athletes often describe pain in the groin with deep flexion or rotation of the hip during activity. Occasionally, snapping, popping or clicking in the front of the hip is described. Pain may also radiate along the side of the thigh and into the buttocks. It is important to rule out other causes of pain in this area which may originate in the low back or abdomen.
Symptoms:
- Pain and or stiffness in the thigh, hip, or groin
- The inability to flex the hip beyond a right angle
- Pain in the groin area, particularly after the hip has been flexed (such as after running or jumping, extended periods sitting down, getting into or out of a car)
- Pain in the hip, groin, or lower back that can occur at rest as well as during activity
What are the treatment options of a hip impingement?
Treatment of hip impingement/femoroacetabular impingement begins with conservative, non-surgical methods. Rest, activity modifications, careful use of anti-inflammatory medications, and a course of physical therapy are often successful in alleviating or reducing symptoms. An injection of the hip joint with anesthetic and/or steroid can also provide some relief, as well as diagnostic information in patients with symptoms that are unresponsive to treatment. When surgery is necessary, femoroacetabular impingement can usually be treated with arthroscopic hip surgery.
