Femoro-Acetabular Impingement (FAI)

WHAT IS IT?

Femoro-Acetabular Impingement… Yeahit is a bit of a mouthfulso let’s break it down a bit. The femoro-acetabular joint is the medical term for the hip which is a ball and socket joint.Femoro refers to the femur (the thigh bone). The upper part of the femur is called the femoral head which is the ball of the hip joint. The acetabulum is part of the pelvis and it forms the socket of the hip joint.

In a normal hip joint, the head of the femur is a round ball which fits into a matching spherical cup shaped socket. Articular cartilage covers the surface of the ball & the socket and helps the joint to glide smoothly.The socket (acetabulum) of the hip joint is also ringed by a layer of strong fibrocartilage called the labrum. The labrum helps to create more stability and reduces impact forces in the hip joint.

Impingementis a term which is used to describe the pinching or catching of tissues in the body. In FAI, this is the premature contact between the neck/head of the femur (the ball) and the rim of the acetabulum (the socket). Over time, this impingement can result in increased risk of damage to the labrum or the cartilage of the hip joint.

THE TYPES OF FAI:

There are three types of FAI - Cam, Pincer and Mixed.

Cam:

• Extra bone growth on the neck or head of the femur

Pincer:

• Increased depth of acetabulum (the socket)
• “Over-coverage” -The socket therefore covers too much of the femoral head

Mixed:

• Combination of both cam and pincer lesions

WHAT CAUSES IT?

For most people, there is no known cause for the development of femoro-acetabular impingement however it is thought it may sometimes be related to developmental causes, after trauma/surgery or if there is a history of childhood orthopaedic conditions such as Perthes Disease or Slipped Upper Femoral Epiphysis (SUFE).It tends to be more common in the young athletic population, especially those that are highly active or involved in sports that require a lot of hip flexion and rotation and/or contact(e.g. gymnastics, dance, hockey, football). It can however also occur in older and more sedentary people.

WHAT ARE THE SYMPTOMS?

• Pain in the front of the hip or groin
• Pain can sometimes also be felt in the back, buttock or thigh
• Pain that is related to a specific movement or position of the hip (usually involving flexion and internal rotation)
• Pain that worsens with physical activity or prolonged sitting
• Clicking, catching, locking or giving way/feeling of instability
• Stiffness or restricted range of movement
• Onset can either be gradual or sudden

DIAGNOSIS:

• A confirmed diagnosis requires either an x-ray and/or MRI
• Sometimes an image guided local anaesthetic injection into the hip joint is used to determine whether the pain is coming from the hip or if it isreferred from another structure (e.g. Lumbar spine)

TREATMENT:

Treatment of symptomatic FAI may include conservative management, physiotherapy led rehabilitation and/or surgery.

Conservative management is a wait & see approach involvingeducation, lifestyle & activity modification,oral analgesia (non-steroidal anti-inflammatories) and intra-articular steroid injections.

Physiotherapy led rehabilitation can have a place in the treatment of FAI by identifying the factors that may be contributing to the issue and addressing these.

The aim of physiotherapy is to:

• Improve hip range of motion
• Increase strength of hip/pelvic muscles (e.g. glutes, ‘core’ muscles)
• Improve control of movement around the lumbar spine, pelvis& hip

Physiotherapy treatment may include:

• Activity modification
• Gentle stretching exercises
• Gluteal & Core strengthening exercises
• Manual therapy: hip joint mobilisations, massage, dry needling

For those people with confirmed FAI and labral tears, a trial of physio-led rehabilitation is a short term option to consider before heading down the surgery pathway. If after a period of consistent rehab there is no change then it is unlikely that further efforts will make a huge difference. This lack of improvement, despite addressing the potential contributing factors, is usually because there are significant bony changes in the hipthat needs to be addressed that no amount of rehabilitation will change.  In this case, an opinion from an orthopaedic surgeon should be sought to determine whether surgery is an appropriate treatment option.

SURGERY:

Surgical intervention can vary on a case by case basis, but it is now mostly done arthroscopically (key-hole surgery). The aim of surgery is to improve the hip morphology (i.e. correcting the abnormalities of the bone) and to either resect, repair or reconstruct the damaged tissue (labrum/cartilage) to allow impingement free motion. Post-operatively, physiotherapy can assist to restore hip range of motion, strength and stability to facilitate return to sport and normal activities.

It is important to note that preventative surgery to correct deformities is not recommended in individuals with evidence of bony abnormalities but no hip symptoms.

PROGNOSIS:

Symptoms of FAI frequently improve with treatment and most people are able to return to full activity including sport.After surgical correction of FAI, it is generally recommended that return to sports does not occur until 4-6 months post operatively but this can depend on the type of surgery and the condition of the hip joint. Without any treatment, there is the potential for symptoms to worsen over time. Current research does not provide enough evidence on what the long term outlook is for people with FAI and it is unknown at this stage whether getting treatment for FAI syndrome can prevent hip osteoarthritis in the future.

If you are experiencing pain or symptoms like these, have your hip assessed by a Made To Move Physiotherapist today. You can call us at our Warwick clinic on (08) 6244 0345 or send us an email via [email protected]

REFERENCES:

Griffin DR, Dickenson EJ, O'Donnell J, et al. The Warwick Agreement on femoroacetabular impingement syndrome (FAI syndrome): an international consensus statement. Br J Sports Med 2016;50:1169-1176.

Byrd, J. W. T. (2010). Femoroacetabular Impingement in Athletes, Part 1: Cause and Assessment. Sports Health, 2(4), 321–333.

https://doi.org/10.1177/1941738110368392

Byrd, J. W. T. (2010). Femoroacetabular Impingement in Athletes, Part II: Treatment and Outcomes. Sports Health, 2(5), 403–409. https://doi.org/10.1177/1941738110378987