Femoroacetabular Impingement

What is Femoroacetabular Impingement?

Femoracetabular Impingement (FAI) is a hip condition that occurs when the ball (femoral head) and socket (acetabulum) rub abnormally creating damage to the hip joint. The 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) resulting in painful hip movements. Research suggests that there is an association with FAI and development of hip osteoarthritis.

Types of Femoracetabular Impingement

cam lesion

Cam Type

In Cam type FAI the usually spherical femoral head (ball) is abnormally shaped resulting in jamming of the femoral head against the rim of the socket (acetabulum).

This type of FAI is most commonly seen on young athletic men.

Pincer Type

In Pincer type FAI bone spurs formed on the end of the cartilage on the socket of the hip joint (acetabulum) cause painful pinching during activities where the hip is flexed. This occurs in the area of the thigh bone (femur) just below the ball, called the neck of the femur, may bump into the rim of the socket. This type of impingement is more commonly seen in middle aged women.

Mixed Type

In many cases there is a combination of both Cam and Pincer impingement and this is called mixed impingement.

What Causes Femoracetabular Impingement?

FAI occurs when the hip bones do not form normally during childhood. Over time the deformity of a cam bone spur, pincer bone spur, or both, leads to joint damage and pain.

Studies suggest that many people who have no symptoms of hip impingement show findings of FAI on X-Ray. This suggests that the hip needs to be aggravated in some way for symptoms to develop and this explains the tendency for athletes, sporting professionals and active people to be more susceptible to this form of injury.

Sports that may commonly aggravate FAI include: gymnastics, cycling, football, soccer and dancing.


  • Pain is typically felt deep in the groin (at the front of the hip) but may be felt to the side of the hip or in the buttock.
  • Restricted or painful range of hip motion
  • Onset is often insidious, and may be associated with increased activity.
  • Onset can be acute or following injury.
  • Typically pain is provoked by: prolonged sitting, walking, crossing legs, getting in and out of the car and pivoting in sports.


Assessment of hip pain involves the physiotherapist taking a case history and then performing a thorough physical examination. This will include assessment of functional activities such as walking and sitting as well as range of motion, strength and screening of other joints including the lumbar spine.

In the clinic the most accurate test to diagnose FAI is the hip impingement test. This test involves the physiotherapist moving your hip into hip flexion, adduction and internal rotation. A positive test occurs when pain is reproduced.

Your physiotherapist may also refer you for a radiograph (X-Ray) or MRI of your hip to confirm the diagnosis of a FAI.


In most patients it is recommended that a period of conservative (non-operative) management is trialled before considering surgical correction.

Techniques your physiotherapist may use to help treat this injury include:

  • soft tissue massage and joint mobilisation
  • dry needling
  • the use of crutches (if the pain is very severe)
  • ice or heat treatment
  • biomechanical correction (e.g. the use of orthotics)
  • activity modification advice
  • weight loss advice where appropriate
  • education
  • progressive exercises to improve flexibility, balance and strength
  • clinical Pilates, hydrotherapy or gym based rehabilitation
  • a gradual return to running program
  • a gradual return to sport or activity program

Your physiotherapist may also recommend you consult your doctor for advice regarding anti-inflammatory medication and pain killers to help manage your pain, particularly in the early stages.

Hip Surgery for Femoroacetabular Impingement?

If a period of conservative management fails to improve your symptoms then a referral to an orthopaedic surgeon may be indicated. You will need to see your GP for a referral to an orthopaedic surgeon.

Surgical treatment for FAI is most commonly performed arthroscopically, but sometimes involves open debridement. Surgery for FAI aims to correct any bony abnormalities to the ball or socket of the hip joint as well as repairing any associated labral tear.

Following surgical correction of FAI you will need to undergo a supervised rehabilitation program with your physiotherapist.

Your rehabilitation time will depend on the level of activity you wish to return to but most patients resume normal activities after FAI surgery within six weeks. Full recovery and return to sport will be guided by your surgeon and physiotherapist and may take up to six months. Studies show that 80-90% of patients return to athletic activity after surgery.

For more advice about femoroacetabular impingement, book now with one of our Physiotherapists at Total Physiocare!

Post compiled by Claire Devos (Physiotherapist)

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