Femoroacetabular impingement (FAI) is a condition where there is too much friction in the hip joint from bony irregularities, causing pain and decreased range of hip motion.
The hip joint is a ball and socket joint. In FAI, the ball of the long leg bone may rub up against the socket, damaging cartilage or tissue and causing pain. Over time, more cartilage and tissue is lost until the ball and socket impact on one other. This bone-on-bone friction is commonly referred to as osteoarthritis.
There are two kinds of FAI:
Cam Impingement. The femoral head is not perfectly round, due to excess bone that has formed. This causes unnatural contact between the surfaces.
Pincer Impingement. The socket has overgrown or is too deep and covers too much of the femoral head, resulting in the cartilage being pinched. It may also be caused when the socket is angled backwards.
Most diagnoses of FAI include a combination of the Cam and Pincer forms.
What are the symptoms of FAI?
Symptoms of FAI can include:
• Groin pain associated with hip activity
• Complaints of pain in the front, side or back of the hip
• A dull ache or sharp pain
• Locking, clicking or catching sensation in the hip
• Pain in the inner hip or groin area after prolonged sitting or walking
• Difficulty walking uphill
• Restricted hip movement
• Low back pain
• Pain in the buttocks or outer thigh area
How is FAI treated?
Non-operative treatments may relieve pain and immobility and may include:
• Activity modification and limitations
• Anti-inflammatory medications
• Physical therapy
• Steroid and analgesic injections
Surgery such as a hip arthroscopy can be done when conservative treatment measures fail to provide relief.