Femoroacetabular Impingement

Femoroacetabular Impingement

Femoroacetabular impingement (FAI) is a condition characterised by excessive friction in the hip joint from bony irregularities, causing pain and decreased range of hip motion. The femoral head and acetabulum rub against each other, creating damage and pain to the hip joint. The damage can occur to the articular cartilage (smooth tissue that cushions ends of bones to facilitate smooth joint movement) or the labral tissue (the lining of the edge of the socket) during normal movement of the hip. The articular cartilage or labral tissue can fray or tear after repeated friction. Over time, more cartilage and labrum is lost, until eventually the femur and acetabulum painfully impact on one other.

FAI impingement generally occurs as two forms:

Cam impingement

The cam form of impingement is when the femoral head and neck are not perfectly round, most commonly due to excess bone that has formed. This lack of roundness and excess bone causes abnormal contact between the surfaces.

Pincer impingement

The pincer form of impingement occurs when the socket or acetabulum rim has overgrown and is too deep. It covers too much of the femoral head, resulting in the labral cartilage being pinched. The pincer form may also be caused when the hip socket is abnormally angled backwards, causing abnormal impact between the femoral head and the rim of the acetabulum.

Symptoms of FAI

The symptoms of femoroacetabular impingement can include the following:

  • Groin pain with hip activity
  • Complaints of pain in the front, side or back of the hip
  • Pain, that may be described as a dull ache or sharp pain
  • Locking, clicking or catching sensation in the hip
  • Pain often occurring to 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

Risk factors

A risk factor is something that is likely to increase your chance of developing a disease or condition. Risk factors for developing femoroacetabular impingement may include the following:

  • Athletes including football players, weight lifters and hockey players
  • Heavy labourers
  • Repetitive hip flexion
  • Congenital hip dislocation
  • Anatomical abnormalities of the femoral head or angle of the hip
  • Legg-Calves-Perthes disease, a form of arthritis in children where blood supply to a bone is impaired, causing bone breakdown
  • Trauma to the hip
  • Inflammatory arthritis


Your doctor will review your

  • medical history and perform
  • a thorough physical examination.
  • Diagnostic studies including X-rays, MRI scans and CT scan may also be ordered to confirm on the diagnosis.
  • Most diagnoses of FAI include a combination of the cam and pincer forms.

Treatment options

FAI can be treated with nonsurgical or surgical methods.

Nonsurgical management of FAI will probably not change the underlying abnormal biomechanics of the hip causing the FAI, but may offer pain relief and improved mobility.

Conservative treatment measures may include:

  • Rest
  • Activity modification and limitations
  • Anti-inflammatory medications
  • Physiotherapy
  • Injection of steroid and analgesic into the hip joint

When conservative treatment measures fail to provide relief, surgery is recommended. Hip arthroscopy is performed where the FAI is surgically treated with the help of an arthroscope, a narrow lighted tube with a camera. This is a minimally invasive surgery that is performed through two or more small incisions.

Luton and Dunstable University Hospital
  • Spire Healthcare
  • OSD Healthcare
  • The London Clini
  • One Hatfield Hospital
  • http://cobhamclinic.co.uk/
  • The Royal College of Surgeons of Edinburgh