Hip Impingement (Femoro-Acetabular Impingement)
The hip joint is formed by the thighbone that presents as a round ball (called the femoral head) to a socket on the side of the pelvis called the acetabulum. The normal shape of the ball and the socket allow close contact through a large range of motion.
What Is Impingement?
As we all need to bend the hip forwards more than in any other direction, the normal socket and ball are turned forwards allowing more motion to bend the hip forward before they jam. Due to congenital and developmental factors, the shape of the ball and the socket may not be ideal, and can cause limitation of hip motion from premature jamming.
Most active people do not feel the jamming and force their hips beyond the possible range to continue their activities. Repetitive forceful jamming of the ball against the socket wall is the most common cause of hip labral tears. Continued jamming causes further damage to the joint cartilage and leads to arthritis at a young age.
Femoro-Acetabular Impingement (FAI)
This jamming is called Femoro-Acetabular Impingement (FAI) as described by Professor Reinhold Ganz from Switzerland in the early nineties. This phenomenon explains the previously unknown causes of hip pain and premature arthritis in young adults.
Repetitive jamming can also thicken the ball and the socket and lead to jamming at lesser range of hip motion. This condition does not cause significant pain in the early stages when treatment can prevent arthritis.
Cam Impingement
Caused by an abnormal bump on the femoral head (ball) that jams against the socket during movement.
Pincer Impingement
Caused by over-coverage of the femoral head by the acetabulum (socket), causing the rim to pinch the labrum.
Current Treatment Options
The current treatment options are limited to simple observation or surgical intervention. There are no known medications to correct the impingement and physiotherapy can do more damage. Surgery is an option if the surgeon can safely identify and correct the bony abnormalities without causing further damage.
This can be done with arthroscopic, open, or combined techniques. Each of these techniques has unique advantages and disadvantages.