Femoroacetabular Impingement (FAI) is a rarely diagnosed and often a misunderstood cause of hip pain. 

For many years, if you sought treatment for the hip pain, you may have been given a diagnosis ranging from a hip sprain or strain to a sportsman’s hernia based on X-rays what were considered normal at that time. For many years, this has likely been a source of misdiagnosed, undertreated and debilitating hip pain for people.

What is FAI?

FAI is caused by a bony growth abnormality of either the femur (thigh bone) called a CAM, acetabulum (socket) called a pincer or both. These abnormalities often cause an abutment of the hip joint during certain movements, namely flexion and rotation, resulting in a pinching sensation or pain in the hip or groin region.

What are the different types of FAI?

There are multiple types of Femoroacetabular Impingement:

  • In CAM-type impingement, the misshapen femoral head (ball) creates friction when you move your hip, especially during squatting motions. This friction will cause bone spurs to develop which damage the hip cartilage leading to hip arthritis.
  • In Pincer-type impingement, an overhang of the acetabulum or socket portion of the hip joint, pinches the labrum cartilage within the hip socket, causing its damage.
  • Finally, a Mixed-type impingement is a combination of the two. 

Is it just a new craze?

The concept of hip impingement has been appreciated since at least 1936. Ganz et al discussed femoroacetabular impingement (FAI) in more detail in 2001, reporting a new surgical approach, and then presenting a hypothesis linking FAI with osteoarthritis in 2003. The number of patients identified with FAI has risen rapidly over the past 10 years due to advancements in the technologies to diagnose the condition.

Who is prone to develop?

It is commonly found in high-level athletes and active individuals. I doubt it may ever be diagnosed in an individual with a sedentary lifestyle.

What are the symptoms of FAI?

Common symptoms of FAI include: 

  • Pain with sitting 
  • Pain caused due to limited squatting
  • Pain, often in the groin, with hip flexion and rotation 
  • Locking or catching with certain activities 
  • Decreased range of motion

Why is it largely undiagnosed?

Many conditions may cause hip pain as well such as low back pain, sacroiliitis, groin strain, iliopsoas tendonitis, etc. So a careful history, exam and plain films are necessary to confirm the diagnosis. Less awareness about the condition among medical personnel is also the reason for delayed diagnosis.

How is it diagnosed?

A careful history and examination by an orthopaedic surgeon, who is trained in diagnosing and treating the FAI are needed to diagnose the condition. The plain films are usually necessary to confirm the diagnosis. 

If suspected, an MR Arthrogram is usually ordered to confirm if there are any labral tears. Physicians also use an injection with an anaesthetic to see if the pain is truly coming from the hip joint. Early diagnosis and treatment are very important to prevent cartilage damage, joint deterioration and arthritis in future.

What are FAI treatment options?

FAI can be treated conservatively or with surgery if necessary.

Conservative (non-operative) treatments can include:

  • Activity modification
  • NSAIDs
  • Physical therapy
  • Intraarticular injections

Surgical treatments can include:

  • Hip arthroscopy
  • Open surgery