Femoroacetabular Impingement (Hip FAI)

What causes hip impingement?

The hip is a ball and socket joint covered in a slippery tissue called articular cartilage. This cartilage helps protect the joint and allows the joint to move smoothly with very little friction. In patients who have hip impingement, this cartilage is worn away quicker than in normal hips because the abnormally-shaped bones move rigidly against each other causing the breakdown of cartilage. Femoroacetabular impingement (FAI) can also lead to tearing of the labrum, a collagenous structure that surrounds the socket of the hip. The labrum is important to protect the articular cartilage and to provide stability to the hip joint. Femoroacetabular impingement may begin in childhood and is a major contributing factor of early degenerative joint disease of the hip in young, active patients.

Are there different kinds of femoroacetabular impingement (FAI)?

There are several distinct types of femoroacetabular impingement. Patients may be diagnosed with one specific type, or a combination of these conditions:

• Cam Impingement: This type of hip impingement occurs because of a misshaped femoral head and neck junction. If the ball of the femur is not round and smooth, it cannot rotate correctly inside the socket (acetabulum) – Cam deformities of the hip are often referred to as placing a square peg in a round hole. This anatomic abnormality causes excessive grinding against the cartilage inside the joint and can tear the labrum.
• Pincer Impingement: This type of hip impingement occurs when the front rim of the hip socket (called the acetabulum) sticks out too far. The neck of the femur (thigh bone) bumps into the protruding rim of the socket during normal hip flexion. This may cause damage to the articular cartilage and may crush the labrum.
• Cam and Pincer Impingement: Some patients exhibit a combined impingement where both the pincer and cam impingements are present.

How common is FAI?

While FAI is somewhat common, it is unknown how many people have it. Some individuals have femoroacetabular impingement and will never know as long as they remain asymptomatic. In most cases, when symptoms do appear, it is because damage to the articular cartilage or labrum has begun and this can be a red-flag signaling that degeneration may continue to progress without proper treatment.

What are the symptoms of femoroacetabular impingement?

Patients in New York typically report the following symptoms of FAI:

• Sharp, ongoing pain in the groin area, especially when the hip is flexed and internally rotated (turned inward).
• Pain that radiates to the outside of the hip.
• Pain that can vary from a dull ache to stabbing and intense.
• A limp when starting to walk.
• Stiffness and decreased range of motion

How is FAI diagnosed?

Dr. Nwachukwu will examine the hip to determine if femoroacetabular impingement is the cause of a patient’s symptoms. He will conduct a detailed physical exam, consisting of multiple tests. One specific maneuver is called an impingement test, where he moves the knee closer to the chest and then rotates it in towards the shoulder. If this causes groin pain, FAI may be the diagnosis. In almost all cases, Dr. Nwachukwu will also use imaging to evaluate the joint. X-rays provide the opportunity to look at the bone itself and determine if they are misshapen. In many cases, Dr. Nwachukwu will also utilize an MRI (magnetic resonance imaging) scan to examine the soft tissues and cartilage within the hip in order to evaluate the hip labrum, cartilage and other soft tissue structures around the hip.

How is femoroacetabular impingement treated?

Non-surgical Treatment:

Treatment for femoroacetabular impingement will depend on the severity of symptoms. Some patients will be able to be treated conservatively with the first recommendation being a change of activity and physical therapy. If certain activities such as sports or lifting are causing the pain, Dr. Nwachukwu may recommend avoiding these activities for a short period of time. Non-steroidal anti-inflammatory drugs (NSAIDs) can also be of benefit along with activity modification. In some cases, Dr. Nwachukwu will recommend a hip joint injection. Hip injections can be useful for providing pain relief and in some patients can provide sustained long-term relief. If long-term relief is obtained then injections can be safely administered periodically. Adequate pain relief from a hip joint injection can also be useful for identifying the hip joint as the primary source of pain. You should expect to have a detailed conversation with Dr. Nwachukwu about your non-operative treatment options.

Strengthening Exercises to avoid surgery for FAI:

Dr. Nwachukwu has a series of hip mobility and strengthening exercises to help patients avoid surgery for femoroacetabular impingement. This series of videos can be found here: Hip Exercise Videos.

Surgical Treatment:

Dr. Nwachukwu will only recommend surgery after an adequate trial of non-operative treatment. In patients requiring surgery for the treatment of femoroacetabular impingement, Dr. Nwachukwu will use an arthroscopic surgical approach. Femoroplasty is done using small incisions and thin, small surgical instruments. Dr. Nwachukwu will use a small camera to view the inside of the hip and he will repair any damage to the labrum and articular cartilage. In addition, part of the surgery will involve re-shaping the hip joint to remove anatomic abnormalities and mechanical impingement.

To address the different types of impingement, there are various surgical procedures that may be utilized. For instance, in cases of pincer impingement, Dr. Nwachukwu may trim the bony rim of the socket (acetabulum). In cases of cam impingement, he may shave down the bump on the ball (femoral head). Surgery for FAI usually helps to reduce the symptoms caused by the impingement as well as helping to slow down or prevent future damage to the hip joint. It is important to note that patients with FAI are potentially at risk for future joint damage. That is why seeking treatment as soon as symptoms appear from a qualified orthopedic hip specialist, has been shown to yield better long-term results. Hip problems can be difficult to diagnose and treat, therefore, it is important to seek treatment from Dr. Nwachukwu who has specific training and expertise in hip arthroscopy.

What is the recovery like after FAI surgery?

It is absolutely essential that patients follow the protocol for post-op recovery as set forth by Dr. Nwachukwu. He will provide a well-supervised physical therapy program following arthroscopic hip surgery so that a normal range of motion and mobility can be achieved. He will start each patient out on a program with highly skilled therapists immediately following surgery so that rehabilitation can begin without delay. For patients who have to travel far to have surgery, the same protocol will be provided so therapy can continue locally once back home.

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For more information on femoroacetabular impingement (FAI) or for additional resources on hip pain and general hip impingement, please contact the office of Benedict Nwachukwu, MD, orthopedic hip specialist serving Manhattan, New York City and surrounding New York boroughs.