What is FAI?

FAI is anatomically described as a subtle abnormality in either or both – the proximal femur and the acetabulum. Femur is the long bone along the length of one’s thigh whereas acetabulum is the cup shaped socket which articulates with the femoral head to form the hip joint. This abnormality causes interference in the normal hip joint motion and is a reason for painful symptoms clinically described as femoroacetabular impingement.

What are the causes and types?

Primarily, there are two major types of impingement – Pincer and Cam.

Pincer type –

For starters, pincer is a tool with blunt concave jaws that are used for gripping and pulling things. Thus, the mechanism of a pincer type FAI is global over coverage of the femoral head circumferentially by the acetabulum and it leads to impingement and gradual degeneration of the hip joint cartilage.

On the other hand, cam is a rotating part in machinery designed to make sliding contact with another part while rotating. In cam mechanism, there is an extra bone formation which renders the usually spherical femoral head to be non-spherical. As a result, during hip motion, there is repetitive friction/abrasion leading to inflammatory changes

Who is affected with FAI?

Usually an active young adult –

  • Football and soccer players as involved in repetitive hip loading and kicking activities
  • Ballet dancers.

What are the symptoms of FAI?

  • Hip and groin region pain along with limited motion is the most common presentation.
  • There could be associated complaints of stiffness, clicking, catching, locking.

How to diagnose FAI?

A radiograph (X-ray) of the symptomatic hip is a useful tool for diagnosing and identifying whether pincer or cam type mechanism is the reason for symptoms. A physical assessment is the clinical key to diagnosis. Physical assessment tests like anterior impingement test, posterior impingement test, FADDIR test are useful clinical tools for the same.

What is the treatment for FAI?

FAI can be managed with physiotherapy or surgical intervention.

Physiotherapy management includes:

  • activity modifications
  • load management strategies
  • improving hip-stability
  • strengthening and
  • range of motion improvement.

Surgical intervention aims to correct the morphological changes in the bone causing FAI; aggressive physiotherapy post operatively is a crucial aspect to recovery.

What is the long term outcome of treatment?

In patients who are treated tend to improve with their activity levels and can aim at returning to previous levels However, evidence suggests, no treatment results in gradual worsening with time with a significant drop in sport/activity participation.