The FABER test is a common orthopedic screening tool used by healthcare professionals to evaluate potential sources of pain in the hip, groin, and lower back region. This maneuver, also known as Patrick’s test or the Figure-Four test, is a non-invasive way to assess the function of two major joints and the surrounding soft tissues. The name FABER serves as an acronym that describes the specific combination of movements: Flexion, ABduction, and External Rotation. This specific positioning helps a clinician identify whether a patient’s pain is originating from the hip joint itself or the nearby sacroiliac joint.
The Anatomical Focus of the FABER Test
The movements of flexion, abduction, and external rotation are specifically chosen to apply mechanical stress to the hip and sacroiliac (SI) joints and the structures that cross them. The hip joint is a ball-and-socket joint, and the combination of these movements brings the thigh bone’s head to the outer limit of its range of motion within the hip socket. This extreme position compresses or stretches the tissues around the hip joint, including the hip capsule, the labrum, and various ligaments.
The test also simultaneously stresses the sacroiliac joint, which connects the sacrum at the base of the spine to the pelvis. As the hip is moved into external rotation and abduction, the force is transferred through the pelvis, creating a rotational torque on the SI articulation. This maneuver is designed to provoke pain if the SI joint is inflamed or dysfunctional. Furthermore, the test stretches soft tissue structures, such as the iliopsoas muscle and adductor muscles, which can also be sources of pain.
How the FABER Test is Performed
The procedure begins with the patient lying flat on their back (supine). The clinician tests one leg at a time, moving the patient’s hip and knee into the starting position. This initial movement involves flexing the hip and placing the foot of the tested leg onto the opposite knee, creating a distinctive “figure-four” shape.
The examiner then stabilizes the pelvis on the side not being tested, typically by placing one hand over the anterior superior iliac spine (ASIS). This stabilization prevents the pelvis from tilting or rotating, ensuring that the stress is accurately applied to the hip and SI joint of the tested side. With the other hand, the clinician applies gentle, sustained downward pressure to the inside of the bent knee, pushing the thigh toward the examination table. The test is complete when the clinician observes the range of motion achieved or when the patient reports the reproduction of their familiar pain.
Interpreting Positive Results
A positive FABER test is characterized by either the reproduction of the patient’s pain or a significant limitation in the range of motion, where the knee cannot drop down toward the table. The interpretation of the result depends on where the patient reports feeling the discomfort. If the pain is localized to the front of the hip or the groin area, it suggests an issue within the hip joint itself, such as intra-articular pathology.
Conversely, if the patient reports pain in the posterior pelvic region, it points toward sacroiliac joint dysfunction. In cases where the knee is significantly restricted from dropping but without marked pain, the finding may indicate tightness in the surrounding soft tissues, such as the hip flexors or adductor muscles. A difference of four centimeters or more in the distance from the table between the two knees is often considered a significant restriction.
Specific Conditions Indicated
A positive FABER test, when interpreted according to the pain location, helps narrow down the potential diagnoses. Pain localized to the groin suggests conditions affecting the hip joint’s internal mechanics or structure. These can include hip osteoarthritis, which causes joint stiffness and pain, or an acetabular labral tear, which is a tear in the cartilage rim of the hip socket.
The test can also indicate femoroacetabular impingement (FAI), a condition where abnormal bone growth causes premature contact between the ball and socket of the hip. When the pain is localized to the back of the pelvis, sacroiliac joint dysfunction or sacroiliitis are common indications. A positive test may also suggest extra-articular conditions, such as iliopsoas tendonitis, which involves inflammation of the major hip flexor tendon.