The FABER test is a common screening maneuver used in orthopedic and physical therapy examinations to help isolate the source of pain in the lower body. The name is an acronym for the three movements involved: Flexion, ABduction, and External Rotation of the hip. This simple, non-invasive assessment is also called Patrick’s Test or the Figure-4 test, based on the shape the leg forms during the procedure. It provides a quick way for clinicians to determine if a patient’s discomfort in the groin, hip, or lower back originates from the hip joint itself or from the nearby sacroiliac joint.
Anatomy Assessed by the Test
The FABER test positioning stresses multiple anatomical structures around the pelvis and hip, allowing for differential diagnosis. The combination of flexion, abduction, and external rotation places a rotational and compressive force directly onto the hip joint capsule. This maneuver is designed to compress or stretch structures within the hip socket, such as the articular cartilage and the acetabular labrum.
The figure-4 position also transmits significant force across the sacroiliac (SI) joint, which links the sacrum to the pelvis. The stress on the SI joint helps to provoke pain if there is inflammation or dysfunction in that area. Beyond the joints, the test stretches surrounding soft tissues, including the iliopsoas muscle, a powerful hip flexor, and the hip adductor muscles located on the inner thigh. Pain elicited from these muscular structures can sometimes mimic joint pain, providing important information to the clinician.
Performing the FABER Test
The test begins with the patient lying supine on an examination table. The clinician then guides the leg being tested into the figure-4 shape by flexing the hip and knee. The ankle of the tested leg is placed just above the knee of the opposite, straight leg, achieving the required flexion, abduction, and external rotation.
Once the leg is in this configuration, the examiner uses one hand to stabilize the patient’s pelvis on the opposite side, typically over the anterior superior iliac spine (ASIS). This stabilization prevents the pelvis from rotating, ensuring the force is concentrated on the hip and SI joint.
The clinician then applies a gentle, gradual downward pressure to the inside of the bent knee, pushing it toward the examination table. This downward pressure, called overpressure, further stresses the hip and SI joint to reproduce the patient’s familiar pain. The examiner carefully observes both the patient’s physical reaction and the degree to which the knee drops toward the table. A restricted range of motion or a sudden report of pain indicates a positive result, and the exact location of that pain is crucial for interpretation.
Clinical Meaning of a Positive Result
A positive FABER test, defined by the reproduction of the patient’s pain, points toward the general location of the pathology. The interpretation is highly dependent on where the patient reports feeling the discomfort. Pain reported anteriorly, in the groin area, strongly suggests a problem originating from the hip joint itself.
This anterior pain can be a sign of intra-articular hip conditions, such as hip osteoarthritis, which involves degradation of the joint cartilage. It may also indicate a labral tear, a common injury to the ring of cartilage that lines the hip socket, or femoroacetabular impingement (FAI). In these cases, the FABER position compresses the inflamed or damaged tissue within the joint, causing the characteristic groin pain.
Conversely, if the patient reports pain posteriorly, in the buttock region or lower back, the finding is more indicative of pathology within the sacroiliac (SI) joint. The stress applied during the test torques the SI joint, and pain in this area often suggests inflammation or dysfunction. A healthcare provider will often combine this positive finding with other specific SI joint tests to confirm the diagnosis.
If the patient experiences limited range of motion (the knee does not drop close to the table) but reports no significant joint pain, this suggests tightness in the surrounding muscles. Restricted movement without pain can be attributed to tightness in the hip flexors, like the iliopsoas, or the adductor muscles of the inner thigh. Given the non-specific nature of the FABER test, a positive result necessitates further diagnostic evaluation, such as specialized imaging or injections, to confirm the precise underlying cause of the patient’s pain.