Femoroacetabular impingement (FAI), is a condition of the hip where the bones of the hip joint are not shaped anatomically and there is a resultant impingement of soft tissues in the hip as a result of bone deformity. The most common form of FAI is a cam deformity wherein the femoral head has a “bump” (CAM) and does not fit appropriately into the hip socket. This type of deformity can be compared to trying to place a square peg into a round hole. As a result of FAI and improper biomechanics, damage to the hip articular cartilage or labrum can occur.
What are the Symptoms of FAI?
Patient’s with FAI will often complain of hip stiffness and groin pain and may at times be incorrectly diagnosed as having a groin pull or hernia. Activities requiring hip flexion (e.g. sitting, squatting) can aggravate FAI symptoms. I have found that in an active New York population – cycling around central park, spin class, certain yoga positions and high intensity events like Crossfit can be triggers of hip pain. In less active patients, things like sitting for extended periods of time can trigger hip pain.
FAI and Professional Sports
FAI related hip injuries and their treatment are now being increasingly recognized in professional sports. A recent case series of hip arthroscopies performed at Hospital for Special Surgery alone reported excellent outcome with FAI surgery performed on 40 National Football League (NFL) players. An intriguing question is though: are we picking up the diagnosis of FAI too late in our professional, amateur and even recreational athletes?
The general prevalence of FAI is not well known and it is theorized that many people have this condition but it does not cause problems. Epidemiological studies have suggested a prevalence of CAM deformities as high as 60% – however the majority of those CAM deformities are symptomatic in the hip. In most cases, patients will only end up in my office when their FAI has reached the point of causing problems – i.e. tear of the hip labrum, cartilage wear or general joint inflammation (synovitis).
We don’t conclusively know why femoral head abnormalities develop but the available evidence suggests that FAI is the body’s adaptive response to stress seen at the femoral head growth plate during youth sports. Some have even gone as far as saying that these CAM deformities confer a strength and propulsive advantage. Others have argued that femoral head deformities are a precursor to hip osteoarthritis. Regardless of the etiology, we know that there are a lot of athletes walking around with stiff hips – whether symptomatic or asymptomatic.
What Should We Do When Athletes Report Hip Stiffness and Groin Pain?
I believe that an important first step when a patient complains of hip stiffness and groin pain is simply recognizing that FAI exists and increasing awareness of this condition. By reading this blog you are already ahead of the curve. Beyond that, I think that understanding the basic hip range of motion for our high level and recreational athletes is important. In particular, decreased (or even absent) hip internal rotation can be a sensitive screen for hips at risk for impingement.
As alluded to earlier, decreased hip range of motion can have effects on non-hip regions. We now understand that hip impingement and limited hip range of motion can lead to increased risk for anterior cruciate ligament injury and can contribute to hip-spine syndrome (increased stress through the lumbar spine due to restricted hip motion). Given the interconnectedness of the hip with the core, lumbar spine and lower extremities, I believe that addressing early and/or asymptomatic hip impingement may be beneficial for reducing general spine/lower extremity injury risk and progression to symptomatic FAI. In our athletes with asymptomatic diminished hip range of motion it is especially important to emphasize core & pelvic strengthening, overall flexibility and maintenance of mobility in adjacent joints. I work with a number of qualified therapists in Manhattan, Brooklyn, Bronx, Queens, Long Island, Staten Island, New Jersey and the surrounding Tri-State area.
Understanding the role of the hip joint in overall athlete performance and injury prevention is key and starts with an understanding of femoroacetabular impingement. Ultimately, for athletes that progress to symptomatic impingement, it is important that these individuals are evaluated by healthcare professionals with an understanding of the various possible causes of hip stiffness and groin pain.