FAI: Hip Impingement Syndrome
FAI stands for Femoral Acetabular Impingement or more commonly called hip impingement syndrome. It primarily affects young and middle-aged adults, often showing up as chronic groin pain and decreased range of motion when you bend forward or internally rotate your hip.
There are only two anatomical reasons you can develop impingement syndrome because we have only two things to talk about when it comes to the hip: the ball and the socket. If the ball is shaped more like a mushroom head than a billiard ball, it doesn't fit as nicely in the socket. That is called the "cam" phenomenon where the ball is almost too big for the socket. It pinches the labrum and tears it. The second bony reason the labrum can tear is because the socket is too big compared to the ball. In that case, extremes of motion, such as kicking in front or to the side or rotating in certain ways can cause the edge of the socket to indent into the ball with the labrum stuck in between. That is called the "pincer" phenomenon. Today's MRI shows us the torn labrum, but now with our better analysis, we can say, "The labrum is torn. Is it a cam or a pincer problem?" Once we know that, we can treat the torn labrum correctly. It allows the surgeon to file down the bony bump that is the problem, either the bump coming from the ball side of the joint or the bump crushing the labrum from the socket side of the joint.
When the labrum is torn, this beautiful, rubbery cushion protecting the cartilage of the ball and socket joint begins to act like a piece of sandpaper wedged in between and it starts speeding up the process or arthritis. A labral tear can actually cause the delamination of the cartilage - that is, it can cause the cartilage to "unglue" itself off of the bone. Yet with arthroscopy, we can clean away the torn labrum or surgically repair it through two small puncture sites. At the same time we can file down the bony bump, the beginnings of a bone spur that may have caused the labral tear in the first place. This may postpone or completely prevent the need for a hip replacement for a lifetime. This is why Dr. Klapper is so interested in continuing to pioneer hip arthroscopy procedures.
Ten years ago, we used the scope merely to clean up labral tears. Now we have learned why the labrum is torn and we know we must fix the reason the labrum was torn by filing down the bump on the bone so another tear will not occur.
