FABER Hip Test: Purpose, Procedure, Interpretation, and Limitations

What is the Faber hip test?

The FABER (Flexion, Abduction, External Rotation) hip test is a common orthopedic special test used to assess hip joint pathology, particularly sacroiliac joint dysfunction, hip intra-articular issues, or iliopsoas tightness, by placing the hip in a specific, provocative position.

Understanding the FABER Acronym

The name FABER is an acronym describing the three primary movements the hip joint undergoes during the test:

• Flexion: The hip is bent, bringing the knee towards the chest.
• Abduction: The leg is moved away from the midline of the body.
• External Rotation: The leg is rotated outwards, away from the body's center.

When combined, these movements place the hip in a "figure-4" position, which stresses various structures around the hip and pelvis.

Purpose and Clinical Significance

The FABER test is primarily performed to:

• Screen for Hip Joint Pathology: This includes conditions such as hip osteoarthritis, femoroacetabular impingement (FAI), labral tears, or capsular restrictions. Pain originating from the anterior hip or groin during the test often suggests an issue within the hip joint itself.
• Assess Sacroiliac (SI) Joint Dysfunction: The position of the test can place stress on the SI joint. Pain experienced in the posterior gluteal or sacral region during the test may indicate SI joint involvement.
• Identify Iliopsoas Spasm or Tightness: The flexed and abducted position can stretch the iliopsoas muscle.
• Evaluate Adductor Muscle Tightness: Limited range of motion or pain can indicate tightness in the adductor muscle group on the medial thigh.

It is a valuable component of a comprehensive physical examination but rarely used as a standalone diagnostic tool due to its broad indications.

Anatomy Involved

The FABER test stresses and evaluates several key anatomical structures:

• Hip (Acetabulofemoral) Joint: This ball-and-socket joint, formed by the femur and the acetabulum of the pelvis, is the primary focus. The test assesses the integrity of the articular cartilage, labrum, and joint capsule.
• Sacroiliac (SI) Joint: This joint connects the sacrum to the ilium. The FABER position can create shear forces across the SI joint, making it a useful screen for SI joint pain.
• Muscles:
  • Adductor Group: (e.g., adductor longus, magnus, brevis, gracilis, pectineus) are stretched.
  • Hip Flexors: (e.g., iliopsoas, rectus femoris) are placed in a shortened or stretched position depending on the specific component of the test.
  • External Rotators: (e.g., piriformis, gemelli, obturators) are engaged.
• Ligaments: The hip joint capsule and its reinforcing ligaments (iliofemoral, pubofemoral, ischiofemoral) are stressed. Ligaments of the SI joint are also implicated.

How to Perform the FABER Test

The test is typically performed with the patient lying on their back (supine).

1. Patient Positioning: The patient lies supine on an examination table.
2. Examiner Positioning: The examiner stands on the side of the hip being tested.
3. Test Leg Positioning (FABER):
   • The examiner passively flexes the patient's hip.
   • The ankle of the test leg is then placed onto the opposite knee, creating a "figure-4" position. This automatically places the hip in flexion, abduction, and external rotation.
4. Pelvic Stabilization: The examiner places one hand on the anterior superior iliac spine (ASIS) of the opposite (contralateral) hip to stabilize the pelvis and prevent it from rotating.
5. Application of Overpressure: With the other hand, the examiner gently applies downward pressure to the medial aspect of the flexed knee of the test leg, pushing it towards the examination table.
6. Observation and Assessment: The examiner observes the patient's response, noting any pain, its location, and the range of motion achieved (specifically, how far the knee drops towards the table relative to the opposite ASIS).

Interpreting the Results

Interpretation of the FABER test relies heavily on the patient's reported pain location and the observed range of motion.

• Positive Test (Pain in the Anterior Hip/Groin): If the patient experiences pain in the anterior hip, groin, or deep within the hip joint, it often suggests intra-articular hip pathology, such as:

  • Hip osteoarthritis
  • Labral tear
  • Femoroacetabular impingement (FAI)
  • Capsular tightness or inflammation
  • Iliopsoas bursitis or tendinopathy

• Positive Test (Pain in the Posterior Gluteal/Sacral Region): If the patient experiences pain in the posterior aspect of the hip, buttocks, or specifically over the sacroiliac joint, it is highly suggestive of sacroiliac joint dysfunction.

• Positive Test (Restricted Range of Motion): If the knee of the test leg does not drop below the level of the contralateral leg (or to the examination table), it indicates limited hip mobility. This could be due to:

  • Tightness of the hip adductor muscles
  • Tightness of the hip joint capsule
  • Internal hip joint pathology limiting motion

• Negative Test: A negative test occurs when the patient can achieve full range of motion (the knee drops close to or below the level of the contralateral leg) without experiencing any pain.

Limitations and Considerations

While a valuable test, the FABER test has limitations:

• Non-Specific: A positive FABER test can indicate several different conditions, requiring further evaluation to pinpoint the exact diagnosis. Pain location is critical for differentiation.
• Subjectivity: Interpretation relies on the patient's pain report.
• Technique Dependent: Proper stabilization of the pelvis and correct application of overpressure are crucial for accurate results.
• Not Definitive: It is one piece of the diagnostic puzzle and should always be used in conjunction with a thorough history, other physical examination findings, and potentially imaging studies.

Who Should Perform and Interpret the Test?

The FABER hip test is an orthopedic special test that should be performed and interpreted by qualified healthcare professionals. This includes:

• Physical Therapists
• Chiropractors
• Osteopathic Physicians
• Orthopedic Surgeons
• Sports Medicine Physicians

These professionals possess the anatomical knowledge, clinical reasoning skills, and diagnostic expertise necessary to accurately perform the test, interpret its findings in the context of a patient's overall presentation, and formulate an appropriate treatment plan. It is not a test intended for self-diagnosis.