What is Femoroacetabular Impingement (FAI)?
Femoral Acetabulum Impingement (FAI) is a condition where the bones of the hip are abnormally shaped causing too much friction. The ball (head of the femur) and the socket (acetabulum) move abnormally with one another which may cause damage to the articular cartilage or labrum (fibrous rim around the socket).
FAI usually occurs in two types forms – Cam and Pincer. In the Cam impingement, the head of the femur is not round and cannot rotate inside the acetabulum. A bump forms on the edge of the femoral head that may grind the articular cartilage. Pincer impingement occurs because of extra bone extending around the rim of the socket, causing the acetabulum to be deeper than normal. The labrum may be damaged due to the prominent ring of the acetabulum. Cam and Pincer type impingement may occur simultaneously.
What Causes FAI?
The exact cause of femoral acetabulum impingement is yet to be found however, it is believed to be a combination of genetic and environmental factors. During puberty, abnormal hip bone growth may contribute to being more at risk of developing FAI. Athletically active people may work their hip more vigorously and move the joint into more extreme ranges of movement, and so may start to experience pain than those who are less active; however exercise does not cause FAI.
Symptoms of Femoral Acetabulum Impingement:
- Pain in the groin area, or towards the outside of the hip and restricted range of movement
- Sharp stabbing pain occur with certain movements – turning, twisting, squatting
- Low back pain
- Gluteal pain
- Referred pain into leg
- Movement restricted in high flexion or trying to cross legs – pain may be provoked by these movements
How is FAI treated?
Non-operative management is possible however it involves a change to a less active lifestyle, and long-term commitment to maintaining hip strength. Conservative management will not change the underlying hip biomechanics and the resulting damage of the cartilage, but it may help manage the pain. Non-steroidal inflammatory medicine may be prescribed to reduce pain and inflammation.
Operative management may be recommended by your doctor and physiotherapist if your pain is not relieved by non-surgical treatment and tests have found joint damage caused by FAI. During hip arthroscopy (surgery), the surgeon may clean or remove any damaged labrum or cartilage. FAI may be corrected by trimming the bony rim around the acetabulum or shaving down the bump on the femoral head. Although physiotherapy cannot change the biomechanics of the hip joint itself, it may help to reduce inflammation, improve core stability, improve range of movement and help avoid pain being provoked by certain movements. To discuss what our physiotherapists can do for you, please contact us for an appointment.