Femoroacetabular Impingement (FAI) / Labral tear
The hip joint is a ball-and-socket joint, that allows for a large amount of hip motion. It is also a very stable joint, due to the femoral head (ball) sitting deep within the acetabulum (socket).
The native hip joint is covered with cartilage on both the ball and socket side, that allows the joint to glide with almost no friction. The socket also has a cartilage labrum, that sits on the edge circumferentially, and functions like a gasket, or “O” ring, creating a suction-seal in the joint.
FAI describes a shape mismatch of the bone between the femoral head (ball) and acetabulum (socket). This shape mismatch creates a physical stress between the neck of the femur and the edge of the acetabulum. This stress results in damage to the labrum and the cartilage that lines the joint. When the labrum is damaged or torn, it causes pain. When the cartilage that lines the socket is damaged, it results in a cartilage flap, or cartilage thinning that is difficult to treat.
Both labral tears and cartilage damage can occur in young people. In fact, they mostly occur in active, otherwise healthy people. The damage can be from a specific trauma, although is most often a result of “wear and tear” in patients with FAI.
There are two main types of FAI that have been described, “cam” and “pincer”.
Cam deformities are more common in males and refer to a bony bump on the femoral neck, or the femoral head being “out of round”. An analogy is that of a car tire that is out-of-round, rubbing against the wheel well every time it spins. In this case, the “wheel well” is the edge of the socket. This causes damage to the labrum and a peeling back of the cartilage that lines the socket through the sheer force.
Pincer deformities are more common in females and refer to a socket that is extra deep (coxa profunda, protrusio), or tilted towards the back (retroverted). In this case, the labrum gets crushed by the femoral neck in extremes of hip motion, particularly hip flexion, causing tearing within the substance of the labrum itself.
Most patients with FAI, with have some component of both cam and pincer, but one more significant than the other
Typical symptoms of FAI and labral tear are groin pain, and/or lateral hip pain, that is worse with hip flexion, prolonged sitting or standing, worse with exercise, or getting into or out of a vehicle. Some people describe the pain by making a “C” with their hand and grabbing the side of their hip. This is because the pain is from deep within the hip and difficult to precisely localize.
Other symptoms include a painful snapping in the front, or side, of the hip or a catching sensation when going from a seated to standing position.
The pain is typically characterized as sharp/stabbing, but there can be a baseline dull/achy pain as well.
Treatment for FAI and a labral tear can be either surgical or non-surgical, depending on the severity of symptoms and the success of early non-surgical treatment.
Initial treatment includes avoiding painful activities, pain medication such as anti-inflammatory medications, and physical therapy for muscular conditioning and balancing.
If these treatments fail, and the symptoms significantly interfere with quality of life, hip arthroscopy can be performed to repair the labral tear and treat the cam and/or pincer deformity.
Hip arthroscopy is typically performed as an outpatient procedure, requires 3-6 weeks of using crutches after surgery, and involves formal physical therapy. Return to work/school can be as early as 2-3 weeks, but a full recovery typically takes 3-4 months.
For more information on what hip arthroscopy entails, please see my “Hip arthroscopy booklet”, also in the “Patient Education” section of the website.
Hip Dysplasia refers to the socket (acetabulum) of the hip joint being too shallow. This is essentially the opposite of FAI, but can present with similar signs/symptoms.
In dysplasia, the femoral head (ball) tends to escape out the side of the socket, which damages the labral because the labrum sits on the edge of the socket. This can cause a labral tear, and further hip instability due to breaking the suction seal of the hip joint.
Initial treatments are similar to those of FAI, as detailed above, but with an emphasize on strengthening the hip stabilizing muscles.
Hip arthroscopy can be helpful in mild cases of dysplasia by repairing the labral tear and possibly tightening the ligament in the front of the hip, but cannot correct the shallow socket.
Arthritis can be from osteoarthritis or rheumatoid/inflammatory arthritis. Osteoarthritis is far more common, and is typically what people refer to when they talk about “arthritis”.
The hallmark feature of hip arthritis is damage to, and loss of, the cartilage that lines the socket and caps the ball of the hip joint. This sets off a sequence of pain and inflammation that gradually worsens over time.
Light aerobic forms of exercise, such as walking, cycling, and swimming, can be helpful for symptoms. High impact exercise, such as distance running, often makes symptoms worse.
Arthritis typically progresses in a step-wise fashion, where symptoms will be at a certain level of a period of time, then suddenly increase, often for no apparent reason.
The non-surgical treatment for arthritis is activity modification, pain medication and possibly injections.
Surgical treatment for arthritis is a hip replacement. There are three main surgical approaches for hip replacement: anterior, posterior, and antero-lateral. Each approach offers certain advantages and disadvantages. My preferred surgical approach is the anterior approach.
For more information about hip replacements, please see “joint replacement” in the “specialities” section of the website.
For more education videos related to hip arthroscopy check out: https://www.youtube.com/channel/UCFWEPxGCTEEL-etZWZ5wesg