Femoral acetabular impingement (FAI) is a condition that describes damage to the hip joint due to too much friction caused by the abnormal rubbing of the ball (femoral head) and socket (acetabulum). Damage can occur to the articular cartilage (smooth white surface of the ball or socket) or the labral cartilage (soft tissue bumper of the socket).

FAI is generally caused by one of two ways:

  • Cam impingement – Lack of roundness of the femoral head contributes to abnormal contact between the ball and socket.
  • Pincer impingement – The socket has too much coverage of the ball.

FAI is common in high-level athletes, but also occurs in active individuals. It is believed to be a major cause of early osteoarthritis of the hip in those younger than 40 years in age.

Signs and Symptoms

FAI is not painful in its early stages, meaning a person can have the condition for years and not know it. The main symptoms of FAI are pain in the low back and stiffness in the groin or front of the thigh. If left untreated, FAI is associated with the following:

  • Cartilage damage.
  • Labral tears.
  • Joint laxity.
  • Early hip arthritis.
  • Sports hernias.
  • Subspinous AIIS impingement.
  • Ischiofemoral impingement.
  • Low back pain.

Treatment Options

  • Rest.
  • Modifying activity levels.
  • Exercise.
  • Anti-inflammatory and pain medications.
  • Arthroscopic hip surgery.
  • Open hip surgery.