Femoroacetabular Impingement

What is Femoroacetabular Impingement?

Femoroacetabular Impingement (FAI), sometimes called hip impingement, is a condition where the bones of the hip joint do not move smoothly together. This occurs when there is abnormal contact between the femoral head (ball of the thigh bone) and the acetabulum (hip socket). Over time, this repeated friction can damage the cartilage and labrum within the hip joint, leading to pain, stiffness, reduced movement, and, if untreated, hip arthritis.


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:

  • Young Active Adults: Particularly individuals aged 15–40 years.
  • Athletes: Sports that involve repetitive hip movement increase the risk.
  • Dancers and Gymnasts: Extreme hip flexibility and repetitive motion may contribute.
  • People with Previous Hip Conditions: Childhood hip disorders may alter hip shape.
  • Individuals with Family History: Genetics may influence hip anatomy.
  • People with Repetitive Hip Loading: Heavy physical work or frequent squatting may contribute.


Causes of Femoroacetabular Impingement

FAI develops due to abnormal hip bone anatomy and repetitive mechanical stress within the joint.


Common causes include:

  • Abnormal Bone Development: Extra bone growth around the femoral head or acetabulum.
  • Childhood Hip Disorders: Conditions such as slipped upper femoral epiphysis (SUFE) or Perthes disease can increase risk.
  • Genetic Factors: Some hip shapes may be inherited.
  • Repetitive Sporting Activities: High-impact activities during adolescence may influence hip development.
  • Hip Overuse: Repeated bending and twisting motions may worsen impingement.
  • Previous Hip Injuries: Trauma may alter joint mechanics.


The condition often develops gradually over time rather than from a single injury.


Symptoms of Femoroacetabular Impingement

Common symptoms include:

  • Hip Pain: Persistent pain in the groin, 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.


Preventing Femoroacetabular Impingement

Preventative measures may include:

  • Early Assessment of Hip Pain: Prompt evaluation may help identify problems before significant damage occurs.
  • Maintaining Hip Strength and Flexibility: Balanced muscle support can improve joint mechanics.
  • Avoiding Repetitive Overloading: Limiting excessive deep squatting or repetitive twisting may help.
  • Proper Sporting Technique: Good movement patterns may reduce stress on the hip.
  • Graduated Training Programs: Avoiding sudden increases in training intensity.
  • Cross-Training Activities: Reducing repetitive strain through varied exercise.
  • Core and Pelvic Stability Training: Improving hip control during movement.
  • Managing Childhood Hip Conditions Early: Appropriate treatment may reduce later complications.


Athletes with persistent groin pain, stiffness, or reduced hip movement should seek assessment early to help prevent progression to labral tears or hip arthritis.


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 of the hip joint but do not experience 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.


A 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.


FAQs About Femoroacetabular Impingement (FAI)

Can Femoroacetabular Impingement heal on its own?

FAI does not usually heal on its own because the condition is related to the shape of the hip bones. However, symptoms may improve with activity modification, physiotherapy, strengthening exercises, and avoiding movements that trigger pain. In more severe cases, medical treatment or surgery may be required to prevent ongoing joint damage.


Is Femoroacetabular Impingement the same as hip arthritis?

No. FAI and hip arthritis are different conditions, although FAI can contribute to the development of arthritis over time. FAI involves abnormal contact between the hip bones, while hip arthritis refers to degeneration and wear of the joint cartilage. Untreated FAI may increase the risk of developing early osteoarthritis.


Can I still play sports if I have Femoroacetabular Impingement?

Many people with FAI can continue participating in sports with appropriate management. Mild cases may improve with physiotherapy, stretching, strengthening, and modifications to training routines. However, continuing high-impact activities despite significant pain may worsen joint damage. A medical assessment can help determine safe activity levels.


How long does recovery take after surgery for Femoroacetabular Impingement?

Recovery times vary depending on the severity of the condition and the type of surgery performed. After hip arthroscopy, many patients return to light activities within several weeks, while full recovery and return to sport may take several months. Rehabilitation and physiotherapy are important parts of recovery.


When should I see a doctor about hip impingement symptoms?

You should seek medical assessment if you experience persistent groin or hip pain, reduced hip movement, pain during sport or exercise, clicking sensations in the hip, or difficulty performing daily activities. Early diagnosis and treatment may help reduce the risk of long-term joint damage and arthritis.

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