FAI is a condition that occurs in that hip that can lead to hip pain, snapping and occasional early degenerative arthritis of the hip. The condition occurs in mostly men between the ages of 40 -60 but women are also affected. Essentially FAI is an anatomic condition that occurs because the hip bones are not shaped properly. The abnormal shape leads to “impingement” which can result in damage to the surface of the hip (articular cartilage) or the supporting structures of the hip socket(labrum).
There are two types of FAI. The cam type occurs when the hip ball is tilted backward causing the neck of the hip ball to “impinge” or hit up against the socket (acetabulum). This abnormality may cause damage to the hip and result in pain as well as early wear of the hip socket. The other type is a pincer hip. This is less common and occurs when the socket of the hip (acetabulum) points backward leading to an overhang of bone that can impinge. As with the cam type, pain and arthritis can result. It is possible to have both cam and pincer type hip FAI.
Symptoms are usually at first vague hip pain. Later on, stiffness, loss of motion and pain with activities occurs. If the condition progresses, pain will begin to occur with walking and stair climbing. Occasionally, patients will have a feeling of “catching” or “clicking” in the hip. The typical patient presents to the primary care physician or orthoapedic surgeon without any history of previous problems of the hip who now has begun to not discomfort in the groin or thigh area.
The diagnosis is usually made with good x-rays taken by an orthoapedic surgeon. There are several special findings such as an “alpha angle” and a “cross over sign” that the orthoapedic surgeon will use to distinguish cam from pincer hips. MRI is also a useful tool. Frequently, the MRI study is performed with contrast which involves the radiologist placing a needle into the hip before the study to inject “contrast” into the hip joint. Occasionally, a “high field machine” such as a 3T MRI, which is a strong magnet MRI ,is used. Computerized Cat Scans (CT)with “reconstruction”, which is a computer program to animate the CT scan into a 3D picture, are very useful.
The treatment for most patients begins with physical therapy and anti-inflammatory agents. Although this will not correct their abnormal anatomy , the inflammation may be permanently reduced. A cortisone injection into the hip is also of value. If the non-operative treatments do not work the patient may elect to undergo arthroscopic surgery or a “mini-open decompression”. The objectives of these surgeries whether done through arthroscopic techniques or by open techniques is to reduce the impingement by shaving the bone spurs from around the hip. This approach is most useful in the cam type hip. The pincer hip will sometimes need more dramatic surgery whereby the surgeon rearranges the position of the hip socket bone (acetabulum). This type of surgery is known as an osteotomy.
Whether FAI is treated by surgery or by non-operative means the primary goal is the relief of the symptoms. There is very little evidence that correcting the anatomic abnormality of FAI will prevent the occurrence of arthritis in the future. Fortunately, the association between FAI and the development of osteoarthritis of the hip is not direct. There are many individuals walking around with this abnormality who never develop pain or findings of arthritis.
