Femoroacetabular Impingement

What is Femoroacetabular Impingement?

Femoroacetabular Impingement (FAI) is a medical condition primarily involving the hip joint. It occurs when there is abnormal contact between the femur (thigh bone) and the acetabulum (hip socket). This abnormal contact can lead to pain and discomfort and, over time, can cause damage to the hip joint.


How Does FAI Impact Your Anatomy and Health?

FAI can significantly impact the anatomy of the hip joint and a person's overall health.


In a healthy hip joint, there is a smooth and frictionless movement between the femur and the acetabulum. In FAI, the shape of either the femur head, acetabulum, or both may be irregular. This can lead to friction and abnormal contact when the hip is moved, causing pain and potentially damaging the joint.


One of the most common effects of FAI is hip pain, especially during activities that involve hip movement, such as walking, running, or even sitting for extended periods.


FAI can restrict the normal range of motion in the hip joint, making it difficult to perform daily activities and participate in physical activities.


Over time, the abnormal contact and friction in the hip joint can lead to hip osteoarthritis, a degenerative condition that can cause further pain and disability.


The pain and limitations caused by FAI can negatively impact a person's overall quality of life, affecting their ability to work, exercise, and enjoy daily activities.


Risk Factors for Femoroacetabular Impingement

FAI can affect people of various ages and backgrounds, but certain factors can increase the risk of developing this condition. These risk factors include:

  • Age: FAI is often seen in young adults and adolescents but can also affect older individuals.
  • Gender: Studies have shown that males are more commonly affected by FAI than females.
  • Genetics: There is evidence to suggest that genetics may play a role in the development of FAI, as it can run in families.
  • Physical Activity: Individuals who engage in repetitive hip movements or high-impact sports may have an increased risk of FAI.


Causes of Femoroacetabular Impingement

Structural abnormalities in the hip joint primarily cause FAI. 


Symptoms of Femoroacetabular Impingement

Common symptoms include:

  • Hip Pain: Persistent pain in the groyne, hip, or lower back, especially during physical activities or after prolonged periods of sitting.
  • Stiffness: Difficulty moving the hip joint with a reduced range of motion.
  • Clicking or Catching Sensation: Some individuals may feel a clicking or catching sensation in the hip joint during movement.
  • Painful Activities: Pain and discomfort during walking, running, squatting, or climbing stairs.
  • Limping: In severe cases, FAI can lead to an altered gait, resulting in a noticeable limp.
  • Pain at Rest: In advanced cases, hip pain may also be present when at rest, affecting sleep and overall comfort.


Types of Femoroacetabular Impingement

FAI can be categorised into three main types based on the underlying structural abnormalities within the hip joint:

  • Cam Impingement:
  • In cam impingement, there is an abnormality in the shape of the femoral head (the hip joint ball). It may have a non-round or aspherical contour, which can cause friction and impingement when the hip is moved.
  • Cam impingement typically leads to damage on the acetabular side of the joint, specifically the labrum (a ring of cartilage that lines the hip socket) and the acetabular cartilage.
  • Pincer Impingement:
  • Pincer impingement occurs when there is an over-coverage of the acetabulum (the hip socket) over the femoral head. This excessive coverage can lead to impingement when the hip is flexed or rotated.
  • Pincer impingement often results in labral tears and damage to the acetabular cartilage.
  • Mixed Impingement:
  • Mixed impingement is a combination of both cam and pincer types. In this case, abnormalities in both the femoral head and the acetabulum increase the risk of impingement.
  • This type of FAI can lead to a broader range of symptoms and may require a tailored treatment approach.


Stages of Femoroacetabular Impingement

FAI can progress through stages of severity, which helps in determining the appropriate treatment approach:

  • Asymptomatic: In the early stages, individuals may have structural abnormalities in the hip joint, but they do not experience any significant symptoms.
  • Mild to Moderate: At this stage, individuals may experience occasional hip pain or discomfort, especially during physical activities.
  • Severe: The symptoms become more pronounced and persistent in the severe stage. Pain and limited hip function are common, impacting daily life and physical activities.


Diagnosis of Femoroacetabular Impingement

Medical History and Physical Examination

Your doctor will begin by discussing your medical history and any symptoms you're experiencing. They will perform a physical examination to assess hip range of motion, pain, and overall function.


Imaging Studies

X-rays are often the initial imaging modality used to assess the hip joint. They can reveal structural abnormalities, such as cam or pincer deformities, and the extent of joint damage.


MRI (Magnetic Resonance Imaging) is useful for assessing soft tissues, including the labrum and cartilage. It can detect labral tears and cartilage damage.


CT (Computed Tomography) Scan may be ordered to provide a detailed three-dimensional view of the hip joint, which can help in surgical planning.


Diagnostic Injections

In certain cases, your doctor may recommend a diagnostic injection of a local anaesthetic into the hip joint. If the pain is significantly reduced or eliminated after the injection, it can help confirm that it originates from the hip joint, indicating FAI.


Specialised Hip Examination

A specialised hip examination, often performed by a hip specialist or orthopaedic surgeon, may include specific tests to assess impingement, instability, and other hip joint issues.


Discussion of Findings and Treatment Options

After a thorough evaluation, your doctor will discuss the findings with you and recommend appropriate treatment options. These may include conservative approaches such as physical therapy and medication or surgical intervention for more severe cases.


Treatment Options for Femoroacetabular Impingement

Conservative Treatment

  • Physical Therapy: Physical therapy focuses on strengthening the hip muscles and improving flexibility and joint stability. It can help alleviate pain and improve hip function.
  • Activity Modification: Avoiding or modifying activities that exacerbate FAI symptoms can be beneficial. This may include reducing high-impact sports or activities that involve repetitive hip movements.
  • Medication: Non-steroidal anti-inflammatory drugs (NSAIDs) or pain relievers may be prescribed to manage pain and inflammation.


Injections

  • Corticosteroid Injections: In some cases, corticosteroid injections into the hip joint can temporarily relieve pain and inflammation.
  • Viscosupplementation: Hyaluronic acid injections can help lubricate the hip joint and reduce discomfort.


Surgical Treatment

  • Hip Arthroscopy: This minimally invasive surgical procedure is often recommended for individuals with moderate to severe FAI. The surgeon can reshape the hip joint during arthroscopy to reduce impingement and repair damaged tissues, such as the labrum.
  • Open Hip Surgery: In rare cases or when the hip anatomy is exceptionally complex, open hip surgery may be necessary to address FAI.
  • Osteotomy: In cases of severe deformity, an osteotomy may be performed to reposition the hip joint, which can alleviate impingement.


What if Femoroacetabular Impingement is Untreated?

Leaving FAI untreated can result in the progression of symptoms, hip osteoarthritis, chronic pain, reduced mobility, joint damage, and a lower quality of life. Therefore, seeking timely medical evaluation and treatment is essential if you suspect you have FAI to prevent these potential long-term consequences and maintain optimal hip joint health.

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