The FABER test is one of the most commonly used physical examination maneuvers for evaluating hip, groin, and sacroiliac joint pain. Its name is an acronym for the position it puts your leg in: Flexion, ABduction, and External Rotation. Clinicians also call it the Patrick’s test or Patrick-FABER test, after the physician who described it. The test stresses multiple structures at once, which makes it useful as a screening tool but also means a positive result can point to several different problems, from labral tears in the hip to sacroiliac joint inflammation.
How the Test Is Performed
You lie on your back on an examination table. The clinician takes your affected leg, bends the knee, and places your ankle or foot on top of the opposite knee so that your leg forms a figure-four shape. From there, the examiner gently presses down on the bent knee, lowering it toward the table while stabilizing your opposite hip with their other hand. Two things are being assessed simultaneously: whether the movement reproduces your pain, and where that pain shows up.
Pain felt deep in the groin or front of the hip suggests a problem inside the hip joint itself, such as a labral tear or cartilage damage. Pain in the back of the pelvis, near the dimples above your buttocks, points toward the sacroiliac joint. Some patients feel pain in both locations, and the examiner notes each one separately. The test takes only a few seconds per side, and comparing the symptomatic leg to the other leg is a standard part of the process.
What the Test Tells You About Hip Problems
When used to detect labral tears and other problems inside the hip joint, the FABER test casts a reasonably wide net. A systematic review looking at studies that compared the test to surgical or imaging findings reported sensitivity ranging from about 41% to 82% and specificity from 18% to 100%, depending on the study and the exact condition being evaluated.1PubMed Central. Sensitivity and Specificity for Physical Examination Tests in Diagnosing Prearthritic Intra-Articular Hip Pathology Are Highly Variable: A Systematic Review That is a wide spread, and it reflects a real limitation: no single bedside test nails the diagnosis of a labral tear with high confidence.
One study that specifically measured how well the FABER test identified confirmed hip pathology found a sensitivity of 0.82, meaning it correctly flagged roughly four out of five people who truly had an intra-articular problem. But the positive predictive value was only 0.46, so fewer than half the people who tested positive actually had the condition the clinician was looking for.2PubMed. The diagnostic validity of hip provocation maneuvers to detect intra-articular hip pathology In practical terms, the test is better at ruling a problem in than at confirming one on its own.
For femoroacetabular impingement (FAI), a condition where abnormal bone shape causes the hip to pinch during movement, the sensitivity numbers look similar, around 81% to 82%. But specificity drops dramatically, ranging from 0% to 25% in the studies reviewed.3PubMed Central. Sensitivity and Specificity for Physical Examination Tests in Diagnosing Prearthritic Intra-Articular Hip Pathology Are Highly Variable: A Systematic Review A near-zero specificity means the test flags almost everyone as positive, including people without FAI. That does not make the test useless for impingement, but it does mean a positive FABER alone cannot distinguish FAI from other causes of hip pain. Clinicians pair it with imaging and other exam maneuvers before settling on a diagnosis.
Why a “Gold Standard” Comparison Is Tricky
One reason the FABER test’s accuracy numbers bounce around so much is that researchers do not agree on what counts as a confirmed positive. Some studies compare the test result to MRI findings, others to what the surgeon sees during arthroscopy, and still others use a diagnostic injection as the standard, checking whether numbing the joint takes the pain away. Each method tells a slightly different story.
A study that used intra-articular injection as the reference found that the FABER test was not useful in distinguishing patients who got substantial pain relief from the injection from those who did not.4PubMed. The diagnostic accuracy of a clinical examination in determining intra-articular hip pain for potential hip arthroscopy candidates That sounds damning, but it highlights an important nuance: the test stresses so many structures at once that even when pain comes from inside the joint, the signal can be muddied by contributions from muscles, the joint capsule, and the sacroiliac joint nearby. The FABER test works best as part of a cluster of tests rather than a standalone verdict.
Screening the Sacroiliac Joint
The same maneuver doubles as a sacroiliac (SI) joint test, and for many clinicians this is its more valuable role. When the examiner presses the knee down, the pelvis is torqued in a way that stresses the SI joint on the same side. If your pain is felt in the back of the pelvis rather than the groin, the SI joint moves to the top of the suspect list.
A study comparing several SI joint provocation tests found that the FABER test had the highest specificity and positive predictive value of the physical tests evaluated. Combining the FABER with the thigh thrust test improved diagnostic ability more than any other two-test combination.5PubMed Central. Accuracy of the Diagnostic Tests of Sacroiliac Joint Dysfunction This pairing is a practical tip worth knowing if you are being evaluated for SI joint pain: if your clinician runs only the FABER and stops, asking whether they also performed the thigh thrust is reasonable, because the two together give a meaningfully clearer picture.
The FABER Test in Inflammatory Back Pain and Spondyloarthritis
Beyond mechanical injuries, the FABER test has a role in detecting inflammatory conditions that affect the sacroiliac joints, particularly spondyloarthritis. In people with chronic low back pain who might have an inflammatory cause, a positive Patrick-FABER test had a sensitivity of about 76% and specificity of roughly 66% for the diagnosis of sacroiliitis, with an overall diagnostic accuracy of 70%.6Clinical and Experimental Rheumatology. Role of Patrick-FABER test in detecting sacroiliitis and diagnosing spondyloarthritis in subjects with low back pain The negative predictive value was about 82%, meaning a negative result is fairly reassuring that sacroiliitis is not present.
In patients already diagnosed with non-radiographic axial spondyloarthritis, where standard X-rays look normal but MRI shows inflammation, the FABER test performed best among the clinical tests studied: sensitivity of 71%, specificity of 75%, and a positive likelihood ratio of 2.9.7PubMed. Assessing the construct validity of clinical tests to identify sacroiliac joint inflammation in patients with non-radiographic axial spondyloarthritis These numbers are not high enough to replace imaging, but they help rheumatologists decide which patients with low back pain should get an MRI of the SI joints in the first place.
Measuring the FABER Distance
Some clinicians go beyond a simple positive-or-negative call and measure the FABER distance, sometimes called the FABER distance test (FDT). Instead of just noting whether the test hurts, the examiner measures how far the bent knee sits above the table at the end of the maneuver. You can think of it as a flexibility measurement: a stiffer or more painful hip lets the knee drop less.
A positive FABER distance test is typically defined as a side-to-side difference of four centimeters or more.8PubMed. Positive FABER distance test is associated with higher alpha angle in symptomatic patients This quantitative approach adds an objective data point that the standard pain-based version of the test lacks. It is especially useful for tracking changes over time, because a number is easier to compare across visits than a subjective pain response. One study also found that patients with a positive FABER distance test tended to have higher alpha angles on imaging, a radiographic marker associated with cam-type impingement of the hip.9PubMed. Positive FABER distance test is associated with higher alpha angle in symptomatic patients
Separately, a study correlating the FABER test with alpha angle found that its sensitivity for cam-type FAI was as high as 93% when using the alpha angle as the reference, with a positive predictive value of about 85%.10Journal of Orthopaedics Trauma Surgery and Related Research. Reliability of FABER test in correlation with alpha angle in diagnosis of cam type femoroacetabular impingement These numbers are substantially better than the systematic review figures for FAI, which suggests that when the condition in question is specifically a bony cam lesion and the reference standard is well defined, the FABER test performs more consistently.
How Consistent Is the Test Between Examiners
A bedside test only matters if two different clinicians would agree on the result. The FABER test does reasonably well on this front. A study of interrater reliability among clinicians assessing musculoskeletal hip pain found a kappa coefficient of 0.63 for the FABER test, which falls in the “substantial agreement” range.11PubMed. The interrater reliability of 4 clinical tests used to assess individuals with musculoskeletal hip pain Bias between raters was low, indicating that disagreements were not systematic in one direction.
A separate reliability study of hip examination tests for femoroacetabular impingement found that about six out of ten tests achieved adequate reliability, defined as agreement above 0.75. Positive agreement across all tests ranged from 0.35 to 0.84.12PubMed. Reliability of hip examination tests for femoroacetabular impingement The overall picture is that the FABER test is reproducible enough for clinical use, but not so airtight that you should be surprised if two different providers reach different conclusions, especially in borderline cases. How hard the examiner presses, the angle of your pelvis at the time, and even your ability to relax can all shift the result.
Pregnancy and Pelvic Girdle Pain
Pregnancy-related pelvic girdle pain is a common condition that can persist well after delivery, and the FABER test is one of the standard provocation tests used to evaluate it. European guidelines for diagnosing and treating pelvic girdle pain list the FABER alongside the thigh thrust, Gaenslen’s test, and the modified Trendelenburg test as recommended pain provocation tests.13PubMed Central. European guidelines for the diagnosis and treatment of pelvic girdle pain
A positive FABER test during pregnancy also has prognostic value. A longitudinal study found that a positive FABER test was a predictor of long-term pelvic girdle pain, roughly doubling the odds that pain would persist years after delivery.14PubMed Central. Predictors and consequences of long-term pregnancy-related pelvic girdle pain: a longitudinal follow-up study Other predictors in that same study included a history of low back pain and positive results on other provocation tests. The takeaway is that the FABER test during pregnancy is not just confirming a diagnosis in the moment; it may also flag women who are more likely to need ongoing treatment and support for pelvic pain after the baby arrives.
What Is Actually Happening Inside the Joint
Imaging studies using dual fluoroscopy have started to reveal what happens inside the hip during the FABER maneuver. In one study that compared people with FAI to asymptomatic volunteers, patients with impingement showed less abduction and external rotation during the test than healthy hips, as you would expect from a joint that runs into a mechanical block.15PubMed Central. In-vivo hip arthrokinematics during supine clinical exams: Application to the study of femoroacetabular impingement But the study also found something less obvious: substantial pelvic motion occurred during the test in everyone, symptomatic or not. Your pelvis does not stay flat on the table the way textbook diagrams imply. It tilts and rotates as the examiner pushes the knee down, and this extra movement varies from person to person.
Dual fluoroscopy paired with model-based tracking can measure these tiny motions with sub-millimeter precision and rotational accuracy under one degree.16Journal of Applied Biomechanics. Accuracy and Feasibility of Dual Fluoroscopy and Model-Based Tracking to Quantify in Vivo Hip Kinematics During Clinical Exams This level of detail is mostly a research tool at this point, not something used in routine clinical care. But it explains why two examiners might judge the same hip differently: if the pelvis compensates more or less depending on how relaxed the patient is, the apparent range of motion in the hip changes even though the actual joint stiffness has not.
Self-Administered Versions and Telehealth
The rise of telehealth prompted researchers to ask whether patients could reliably perform FABER-like maneuvers on themselves, at home, guided by a clinician over video. A proof-of-concept study explored a patient-performed examination designed to diagnose femoroacetabular impingement syndrome and found promising initial agreement with in-person clinical examination.17PubMed Central. Concurrent validity of a patient self-administered examination and a clinical examination for femoroacetabular impingement syndrome The self-examination cannot fully replace the nuance of a trained examiner’s hands, particularly the ability to stabilize the pelvis and control the force applied. But for situations where an in-person visit is not practical, such as rural settings, early screening, or post-surgical monitoring between follow-ups, a guided self-FABER could help clinicians triage who needs to come in.
The concept remains early-stage. The study authors described their results as satisfying a first phase, establishing that the idea is feasible, and called for further validation before the approach could be adopted broadly. If you try the position at home out of curiosity, be aware that without an examiner stabilizing your pelvis, the motion may feel different and the results are harder to interpret. Pain during the movement is worth mentioning to your provider, but do not treat a self-assessed positive or negative as a diagnosis.
When the FABER Test Is Most and Least Useful
The FABER test earns its place in clinical practice not because it gives definitive answers but because it is quick, requires no equipment, and provides a first-pass assessment of several structures at once. It performs best when used as part of a cluster of tests. For SI joint problems, pairing it with the thigh thrust improves accuracy.18PubMed Central. Accuracy of the Diagnostic Tests of Sacroiliac Joint Dysfunction For hip pathology, combining it with the FADIR (flexion-adduction-internal rotation) test and patient history narrows the differential more than any single test.
The test is least helpful in two situations. The first is when you are looking for a single definitive diagnosis and expect the test to deliver one. Its specificity for most conditions is modest, meaning a positive result starts a conversation rather than ending one. The second is when multiple pain generators exist in the same region, such as a labral tear and an inflamed SI joint, because the test may light up for reasons that overlap and confuse the picture. In these cases, imaging and possibly a diagnostic injection become necessary to sort things out. None of that makes the FABER test a bad test. It makes it exactly what it is: a reliable, fast screening tool that tells a clinician where to look next.