Femoroacetabular impingement (FAI) is a condition where the bones of the hip are abnormally shaped and because of this they do not fit together properly. This causes the hip bones to impinge on each other in an abnormal way causing damage to the joint. This causes bone spurs to develop around the femoral head and/or along the acetabulum resulting in even greater impingement. Over time, this can result in the tearing of the cartilage rim around the joint (labrum) and breakdown of the articular cartilage, resulting in arthritis.
There are three types of FAI:
- cam, and
- combined impingement.
Pincer. This type of impingement occurs because extra bone extends out over the normal rim of the acetabulum. The labrum can be crushed under the prominent rim of the acetabulum.
Cam. In cam impingement the femoral head is not round and cannot rotate smoothly inside the acetabulum. A bump forms on the edge of the femoral head that grinds the cartilage inside the acetabulum.
Combined. Combined impingement just means that both the pincer and cam types are present.
Activity changes. Your doctor may first recommend simply changing your daily routine and avoiding activities that cause symptoms.
Non-steroidal anti-inflammatory medications. Drugs like ibuprofen can be provided in a prescription-strength form to help reduce pain and inflammation.
Physical therapy. Specific exercises can improve the range of motion in your hip and strengthen the muscles that support the joint. This can relieve some stress on the injured labrum or cartilage.
If tests show joint damage caused by FAI and your pain is not relieved by nonsurgical treatment, your doctor may recommend surgery.
Many FAI problems can be treated with arthroscopic surgery. Arthroscopic procedures are done with small incisions and thin instruments. The surgeon uses a small camera, called an arthroscope, to view inside the hip.
During arthroscopy, your doctor can repair or clean out any damage to the labrum and articular cartilage. He or she can correct the FAI by trimming the bony rim of the acetabulum and also shaving down the bump on the femoral head. Some severe cases may require an open operation with a larger incision to accomplish this.
(Left) During arthroscopy, your surgeon inserts an arthroscope through a small incision about the size of a buttonhole. (Right) Other instruments are inserted through separate incisions to treat the problem.
Surgery can successfully reduce symptoms caused by impingement. Correcting the impingement can prevent future damage to the hip joint. However, not all of the damage can be completely fixed by surgery, especially if treatment has been put off and the damage is severe. It is possible that more problems may develop in the future.
While there is a small chance that surgery might not help, it is currently the best way to treat painful FAI.