Normal Hip Anatomy

The hip is a ball-and-socket joint made up of the femur (ball) and acetabulum (socket) (Figure 1).

Although the deep socket makes the hip inherently stable, it is further reinforced by a lining (capsule) and a ring of supporting fibrocartilage (labrum). In a normal hip joint, all of these structures function together to allow for movement of the joint without conflict or instability (Figure 2A).


Figure 1 – Normal Hip Anatomy

Figure 2 – Impingement Free Motion

























































What are the typical symptoms for FAI?

Patients with FAI typically present with activity related groin pain and/or mechanical symptoms such as painful clicking and catching deep in the hip. Over time, the pain may become constant and significantly limit the patient’s ability to participate in both recreational activities and activities of daily living.


What is the treatment for FAI?

The first line of treatment is conservative management, consisting of activity modification to avoid positions of impingement, physical therapy to strengthen the surrounding musculature, and various injections to reduce inflammation and provide temporary relief. When these measures fail to provide adequate relief of symptoms, the next step is to surgically correct the underlying structural abnormality.

Surgery for FAI has evolved over the past 15 years, from open surgical dislocation to minimally invasive hip arthroscopy. The goal of surgery is to repair the torn labrum with the use of anchors, reshape the ball and socket by removing excess bone to resolve the impingement conflict, and address any surface cartilage damage by cartilage regeneration techniques. Ideally, surgery for impingement should be performed prior to the onset of significant surface cartilage damage, as this is irreversible and, when present, may result in inferior outcomes.



Can all forms of FAI be treated with minimally invasive hip arthroscopy?

For cam-FAI and pincer-FAI, hip arthroscopy alone is sufficient to completely address all injured structures and reconstitute a normal shape to the hip. Rarely, another developmental parameter (rotational alignment of the femur – or femoral torsion) may contribute to and exacerbate the impingement in the hip, requiring additional treatment. When the femur bone is mal-rotated (femoral retrotorsion), there is excessive hip external rotation and limited hip internal rotation. This shift in the hip’s rotation arc further compounds the negative effects of cam- or pincer-FAI and may require a realignment procedure (derotational femoral osteotomy – or DFO) to restore normal femoral rotational alignment. Although a DFO is performed in a minimally invasive way, the combined surgery results in a more prolonged recovery.


Am I a good candidate for hip arthroscopy?

Whether hip arthroscopy is a worthwhile option for you depends on a number of factors, including:

•  Your age

•  Your particular diagnosis or pattern of injury

•  The extent of arthritis or cartilage damage

In general, the outcomes of hip arthroscopy are best in patients < 50 years of age with focal or discrete structural damage and minimal arthritis. Dr. Mei-Dan will guide you through the various considerations in helping you decide whether hip arthroscopy is right for you.


Choosing the treatment option that is right for you involves careful consideration of your diagnosis, duration and severity of symptoms, desired level of activity, as well as social and financial elements.  You are not alone in this process.


As you research your condition, please write down all of your questions and bring them with you to your next appointment.  Dr. Mei-Dan and his team at CU Sports Med Hip Clinic will take time to address all of your concerns, until you are completely satisfied with your treatment plan.


We look forward to helping you get your life back.

What is FAI?

The term femoroacetabular impingement (or FAI) refers to a condition in which movement of the hip joint is restricted due to abnormal bony contact between the ball and acetabulum socket. A common cause of FAI is a developmental abnormality of the ball resulting in bony overgrowth (cam lesion), which abuts against the rim of the socket during deep flexion (Figure 2B). Alternatively, FAI may come about due to an excessively deep or abnormally oriented socket (pincer lesion) with a similar painful restriction in motion. Sometimes, the bony abnormality is quite subtle and impingement is due to the high demands placed on the hip (ballet, hockey, soccer, etc.). Over time, repetitive impingement can cause tearing of the labrum, surface cartilage damage, and early arthritis.

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Femoroacetabular Impingement (FAI)
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