Hip Pain – Femoroacetabular Impingement (FAI)

WHERE DOES IT HURT? HIP/GROIN

My apologies for skipping around the body a bit, but this month I wanted to write about something that has been coming up frequently as it is gaining a foothold in the Sports Medicine community.  Femoroacetabular Impingement or FAI is considered the diagnosis du jour.  Mayer et al. (1999) first described FAI in a clinical study that supports a strong association between FAI and early onset hip osteoarthritis.  This basically means that you are born with a ball and socket malformation and it leads to arthritis earlier than expected.  To describe this condition in words is difficult so I will defer to the image for a better understanding.  This is a schematic that details your hip joint which is essentially a ball and socket.  The striated area denotes the bone morphology which was a congenital deformation.  For example, imagine that when you go into certain position like a deep squat, you will get a pinching sensation in the front of the hip or the groin.  It is a distinct possibility that the “cam” or “pincer” lesion is the reason for the pain.  The cam lesion exists on the actual femur head.  The femur head is normally spherical in form.  Any change in this shape into a dome-like structure could impinge the joint during  provocative movements.  The pincer lesion exists on the actual socket or acetabulum.  It creates the same pinching sensation.  Most of the time, in fact 86% of the time, there will be a mixed presentation of both the cam and pincer variations that are found in varying degrees together.  

How do you know if you have FAI?  There is an orthopedic test which, when performed and interpreted correctly is a fairly good predictor of the condition.  However, the best way to definitively diagnose FAI is through x-ray.  Unfortunately, x-rays are not the most popular choice for prophylactic diagnostic imaging.  As a result, FAI is not considered until symptoms are already present.  Usually the patient will feel a “groin” pull or pain with or without referred pain down the front of the leg to the knee.  In addition, because of restricted range of motion, the SI joint on the same side can also become affected creating back pain.  As you can see, a whole slew of compensatory problems can therefore manifest.  The most serious of which is a labral tear of the acetabulum.  Labral tears can be diagnosed with an MRI, but our choice is an actual MR Arthrogram.  It has been shown that traditional MRI’s are only about 17% effective in diagnosing a labral tear.  That is not a good enough number for us.  An Arthrogram is upwards of 90% accurate in the diagnosis.  

What to do if you have FAI?  Currently the literature and research dictates that following a conservative care protocol normally produces poor outcomes and surgery is a more probable option.  I personally believe that in the next several years, there will be a more successful conservative approach to resolve these issues.  I hope to be a part of the solution as I continue to research and develop new strategies to combat the problem.  As far as surgery is concerned, new techniques have allowed surgeons to correct the impingement through arthroscopy.  In years past, this was not an option.  Patients would suffer with the discomfort until a hip replacement was inevitable.  Arthroscopy is now believed to help prevent the progression of hip osteoarthritis and if caught early enough, has a fairly good outcome.