The FABER test is a physical exam maneuver used to identify problems in the hip joint, the sacroiliac (SI) joint, or both. The name is an acronym for the four movements involved: Flexion, ABduction, and External Rotation. It’s also called Patrick’s test or the “figure-4 test” because of the shape your leg makes during the exam. Clinicians use it as a quick screening tool when someone comes in with hip pain, groin pain, buttock pain, or persistent low back pain.
How the Test Is Performed
You lie flat on your back on an exam table. The clinician takes the ankle of your affected leg and places it across your opposite thigh, just above the knee. This creates a figure-4 position with your leg bent, angled outward, and rotated. The clinician then applies gentle downward pressure on the bent knee while stabilizing your opposite hip with their other hand. The whole thing takes about 10 seconds per side.
The test is considered positive if it reproduces your pain or if your knee on the tested side can’t drop down to the level of the opposite leg, indicating restricted motion. Where the pain shows up matters just as much as whether it shows up at all.
What Pain Location Tells Your Clinician
The FABER test is unusual among orthopedic tests because the location of pain during the maneuver points toward different underlying problems:
- Pain in the back or buttock: suggests sacroiliac joint dysfunction. This is the most classically cited positive result.
- Pain in the groin: can indicate a hip flexor problem, irritation where the hip flexor presses against the femoral head, or inflammation of the front of the hip capsule.
- Pain on the side of the hip: points toward femoroacetabular impingement (FAI), a condition where the ball and socket of the hip joint don’t fit together smoothly.
- Pain in the back-side area of the hip: suggests impingement between structures near the sit bone and the outer hip bone, particularly in people whose thighbone angles inward more than usual.
This is why clinicians will often ask you to describe exactly where the discomfort is rather than simply noting whether the test hurt.
Conditions the FABER Test Screens For
The test primarily screens for two broad categories: hip joint problems and sacroiliac joint problems. Within those categories, specific conditions include hip osteoarthritis, labral tears and other intra-articular hip damage, sacroiliitis (inflammation of the SI joint), and spondyloarthritis, a family of inflammatory conditions that often affects the spine and SI joints.
For detecting sacroiliitis in people with low back pain, a 2023 study found the FABER test had a sensitivity of about 76% and a specificity of 66%, with an overall diagnostic accuracy of 70%. That means it catches most cases of SI joint inflammation but also flags some people who turn out not to have it. Its negative predictive value was roughly 82%, so a pain-free FABER test is fairly reliable at ruling sacroiliitis out.
For detecting problems inside the hip joint itself, sensitivity runs around 82%, meaning it picks up most intra-articular hip issues. However, its positive predictive value in that context is lower, around 46%, so a positive result alone isn’t enough to confirm a diagnosis. It’s a starting point, not a final answer.
How It Compares to the FADIR Test
If your clinician suspects a hip problem, you’ll likely get both the FABER and the FADIR test. Where FABER moves your hip into flexion, abduction, and external rotation, FADIR does the opposite: flexion, adduction (bringing the leg inward), and internal rotation. The two tests stress different parts of the hip joint and serve slightly different roles.
For femoroacetabular impingement specifically, FADIR is the more sensitive test at around 80%, compared to FABER’s 54%. But FADIR’s specificity is low (about 24%), meaning it produces a lot of false positives. FABER’s specificity for FAI is somewhat better at 38% but still modest. In practice, FADIR is better at ruling FAI out when negative, while neither test alone is strong enough to confirm the diagnosis. That’s why imaging often follows when clinical suspicion is high.
Where the FABER Test Fits in a Workup
The FABER test remains a standard part of clinical guidelines for evaluating hip pain. The 2025 revision of the clinical practice guidelines for hip osteoarthritis, published in the Journal of Orthopaedic & Sports Physical Therapy, lists it as a recommended component of the physical exam alongside range-of-motion and strength testing. It’s considered a best practice measure for assessing joint irritability.
No single physical exam test is definitive for hip or SI joint conditions. The FABER test works best as one piece of a larger picture that includes your symptom history, other provocation tests, range-of-motion measurements, and, when needed, imaging like X-rays or MRI. Its real strength is as a quick, no-cost screening tool that helps clinicians narrow down which structure is causing your pain and decide what to investigate next.