Femoroacetabular Impingement (FAI): Comprehensive Guide to Causes and Management

Femoroacetabular impingement (FAI) is a condition that occurs when there is abnormal contact between the femoral head and the acetabulum in the hip joint. This can lead to damage to the cartilage and labrum, resulting in pain and restricted movement. FAI is increasingly recognised as a significant cause of hip pain, particularly in active individuals.

What is Femoroacetabular Impingement?

The hip joint is a ball-and-socket structure, with the femoral head (ball) fitting into the acetabulum (socket). In FAI, structural abnormalities cause these components to rub against each other abnormally, leading to joint damage over time.

There are three types of FAI:

Cam Impingement: Excess bone growth on the femoral head causes it to lose its spherical shape, leading to impingement during hip movement.
Pincer Impingement: Excess bone extends over the acetabulum, causing it to pinch the femoral head.
Combined Impingement: A combination of cam and pincer abnormalities.

Causes of FAI

FAI develops due to a combination of genetic, developmental, and lifestyle factors. Common causes include:

Congenital abnormalities: Irregular bone shapes present from birth.
Repetitive movements: High-impact or repetitive activities, such as running or ballet, can stress the hip joint and exacerbate structural abnormalities.
Trauma or injury: Previous hip injuries can contribute to irregular bone growth.
Developmental issues: Growth plate injuries or conditions such as slipped capital femoral epiphysis (SCFE) can predispose individuals to FAI.

Symptoms of FAI

The symptoms of FAI can vary but often include:

Hip or groin pain: Worsened by activities such as walking, running, or sitting for extended periods.
Reduced range of motion: Difficulty in rotating or flexing the hip joint.
Clicking, locking, or catching: Sensations in the hip during movement.
Stiffness: Especially noticeable after periods of inactivity.

Symptoms often develop gradually but can be exacerbated by physical activity.

Diagnosing FAI

Accurate diagnosis of FAI is essential for effective management. The process typically involves:

Medical history and physical examination: Identifying symptoms and assessing hip movement.
Imaging studies: X-rays, MRI, or CT scans to identify bone abnormalities and assess cartilage or labrum damage.
Special tests: Physical manoeuvres such as the impingement test, where the hip is flexed, internally rotated, and adducted to reproduce pain.

Treatment Options for FAI

Treatment aims to alleviate pain, improve function, and prevent further joint damage. Options include:

1. Conservative Management

Physical therapy: Exercises to strengthen the hip muscles, improve flexibility, and alleviate symptoms.
Activity modification: Avoiding movements that exacerbate pain, such as deep squats.
Medications: Non-steroidal anti-inflammatory drugs (NSAIDs) to reduce pain and inflammation.
Injections: Corticosteroid or platelet-rich plasma (PRP) injections for pain relief and inflammation control.

2. Surgical Intervention

Surgery is recommended for cases that do not respond to conservative treatment or where there is significant joint damage. Procedures include:

Arthroscopy: A minimally invasive procedure to reshape the femoral head or acetabulum and repair the labrum.
Open surgery: Used for more complex cases to address extensive abnormalities.

Recovery and Rehabilitation

Recovery from FAI depends on the severity of the condition and the treatment approach:

Post-surgery rehabilitation: Physical therapy is crucial for restoring hip strength and mobility.
Gradual return to activity: Patients are advised to avoid high-impact activities during recovery.
Long-term management: Regular exercise and weight management to minimise stress on the hip joint.

Typical recovery timelines range from a few weeks for conservative treatments to several months following surgery.

Preventing FAI

While congenital factors cannot be prevented, the risk of developing FAI can be reduced by:

Maintaining good hip flexibility and strength.
Avoiding repetitive high-impact activities.
Addressing hip pain early to prevent further damage.
Using proper techniques during physical activities and sports.

FAQs

What are the early signs of FAI?

Early signs include groin or hip pain, especially during activities like running or sitting for extended periods. Reduced range of motion and stiffness may also occur.

Can FAI go away on its own?

FAI does not resolve without intervention. However, symptoms can often be managed effectively with conservative treatments like physical therapy and activity modification.

Is surgery always necessary for FAI?

No, many cases of FAI can be managed conservatively. Surgery is typically reserved for severe cases or when conservative treatments fail to provide relief.

How long does it take to recover from FAI surgery?

Recovery from arthroscopic surgery usually takes 3 to 6 months. Full recovery from open surgery may take longer, depending on the extent of the procedure and individual factors.

What activities should I avoid with FAI?

Activities that involve deep hip flexion, such as squats, lunges, or prolonged sitting, should be avoided if they worsen symptoms.

Can FAI lead to arthritis?

Yes, untreated FAI can increase the risk of developing hip osteoarthritis due to continued joint damage over time.

Understanding femoroacetabular impingement is key to managing symptoms and preventing long-term complications. With early diagnosis, appropriate treatment, and preventive measures, individuals can maintain healthy hip function and an active lifestyle.