The most commonly used clinical test for femoroacetabular impingement (FAI) is the FADIR test, which stands for flexion, adduction, and internal rotation. A clinician moves your hip into a specific position to see if it reproduces your groin or hip pain, and a positive result suggests that something inside the joint is being pinched or compressed. But FAI testing rarely stops with a single maneuver. Because no individual physical exam test is accurate enough on its own, diagnosing FAI syndrome typically requires a combination of clinical tests, imaging, and sometimes an injection to confirm the pain source.
How the FADIR Test Works
You lie on your back while the examiner bends your hip to about 90 degrees, then guides the knee inward across your body (adduction) while rotating the thigh inward (internal rotation). The test is considered positive if this movement reproduces your familiar hip or groin pain. The idea is that the combined position jams the femoral head against the front rim of the hip socket, compressing the labrum and any abnormal bony prominences between the two surfaces.
Cadaver research helps explain why this position provokes symptoms. During the FADIR maneuver, pressure in the lateral compartment of the hip joint rises significantly compared to what happens during the opposite movement pattern (flexion, abduction, and external rotation). That pressure difference is substantial enough that researchers have cautioned clinicians to interpret pain during the test carefully, since the high intracapsular pressure alone could cause discomfort even in a normal hip.1PubMed. Intracapsular pressures in the flexion-abduction-external rotation and flexion-adduction-internal rotation tests and their comparison with classic hip range of motion: A cadaveric assessment
How Sensitive and Specific Is FADIR
The FADIR test catches a high percentage of people who actually have FAI, but it also flags many who do not. Across studies, sensitivity tends to be high, often around 80% or above, meaning it rarely misses true cases.2PubMed Central. Combining results from hip impingement and range of motion tests can increase diagnostic accuracy in patients with FAI syndrome A systematic review of studies looking at cam and pincer morphology found that the FADIR test could reach sensitivity as high as 1.00 in some study populations.3BMJ Open. Diagnostic accuracy of clinical tests for cam or pincer morphology in individuals with suspected FAI syndrome: a systematic review
Specificity is where the test falls short. In one analysis, FADIR had a specificity as low as 11%, meaning nearly nine out of ten people without FAI still tested positive.4BMJ Open. Diagnostic accuracy of clinical tests for cam or pincer morphology in individuals with suspected FAI syndrome: a systematic review Other studies have placed specificity in the 24–51% range when combined with different test batteries.5PubMed Central. Combining results from hip impingement and range of motion tests can increase diagnostic accuracy in patients with FAI syndrome In practical terms, a negative FADIR test is somewhat reassuring that FAI is less likely, but a positive result tells you only that something in the hip is irritated. It does not confirm FAI on its own.
Other Physical Exam Tests Used Alongside FADIR
Clinicians rarely rely on the FADIR test in isolation. Several other maneuvers target different aspects of hip joint mechanics, and combining them improves overall diagnostic confidence.
- FABER test: The hip is placed into flexion, abduction, and external rotation, essentially a figure-four position. One study found a sensitivity of 82% for detecting intra-articular hip problems, though its specificity remains low.6PubMed. The diagnostic validity of hip provocation maneuvers to detect intra-articular hip pathology
- Internal rotation overpressure (IROP): The examiner pushes internal rotation past the point of natural resistance with the hip flexed. This maneuver showed a sensitivity of 91% and the highest negative predictive value among provocative tests in one study, meaning a negative result was relatively good at ruling out intra-articular problems.7PubMed. The diagnostic validity of hip provocation maneuvers to detect intra-articular hip pathology
- Stinchfield test: You lift your straightened leg against resistance while lying on your back. This test had the highest specificity of the provocative maneuvers in one comparison, though that number was still only 32%.8PubMed. The diagnostic validity of hip provocation maneuvers to detect intra-articular hip pathology
- Scour test: The examiner compresses and rotates the hip through its arc of motion, essentially grinding the femoral head against the acetabulum. This test is particularly associated with detecting labral tears.9PubMed Central. Physical Examination of the Hip: Assessment of Femoroacetabular Impingement, Labral Pathology, and Microinstability
One study found that combining impingement tests with range-of-motion measurements improved diagnostic accuracy beyond what any single test could achieve. When the FADIR or a similar maneuver was paired with measured reductions in hip rotation, clinicians could better distinguish FAI from other causes of hip pain.10PubMed Central. Combining results from hip impingement and range of motion tests can increase diagnostic accuracy in patients with FAI syndrome
Reliability Between Examiners
One concern with physical exam tests is whether two different clinicians performing the same maneuver on the same patient would reach the same conclusion. Research on inter-examiner reliability found moderate agreement for the main hip tests. The FABER test had a kappa of 0.63, meaning the two examiners agreed more often than chance but not overwhelmingly so. The flexion-internal rotation-adduction impingement test had a kappa of 0.58, which is considered moderate reliability. Bias between examiners was low across all four tests studied, but the impingement test had a very high prevalence of positive results (prevalence index of 0.76), which can inflate apparent agreement.11Journal of Orthopaedic & Sports Physical Therapy. The interrater reliability of 4 clinical tests used to assess individuals with musculoskeletal hip pain Translation: two examiners usually agree on whether your test is positive, but “usually” is not “always,” and finding a different result from a second opinion is not uncommon.
Measuring Range of Motion as a Diagnostic Clue
Restricted internal rotation of the hip is one of the hallmark findings in FAI, and simply measuring how far the hip moves can be as informative as a provocative test. A meta-analysis comparing people with FAI syndrome to healthy controls found that internal rotation at 90 degrees of hip flexion was reduced by roughly 8 degrees, internal rotation with the hip straight was reduced by about 6 degrees, and adduction at 90 degrees of flexion was reduced by around 5 degrees.12British Medical Bulletin. Does femoroacetabular impingement syndrome affect range of motion? A systematic review with meta-analysis Those reductions might sound small, but they are clinically meaningful, especially during demanding activities like deep squatting or kicking.
The type of bony morphology matters here too. After surgical correction, internal rotation improved by an average of about 5 degrees in pincer-type hips, about 9 degrees in cam-type hips, and about 16 degrees in mixed-type impingement, suggesting that combined morphology restricts motion the most.13Clinical Orthopaedics and Related Research®. Range of Motion in Anterior Femoroacetabular Impingement People with imaging findings of FAI morphology but no symptoms tend to have range of motion similar to healthy controls, which reinforces the idea that restricted motion is part of what makes FAI a syndrome rather than just a radiographic appearance.14British Medical Bulletin. Does femoroacetabular impingement syndrome affect range of motion? A systematic review with meta-analysis
Imaging Tests for FAI
Physical exam findings point toward FAI, but imaging confirms the bony morphology causing it. The initial imaging step is usually a set of plain radiographs. Three views are commonly used: an anteroposterior (AP) pelvis film, a cross-table lateral, and a Dunn view, which positions the hip at either 45 or 90 degrees of flexion to profile the front of the femoral head-neck junction.
The alpha angle is the key measurement on these images. It quantifies how much the femoral head deviates from a perfect sphere, with higher values indicating more cam-type deformity. Angles above roughly 50–55 degrees are generally considered abnormal. However, the measured angle varies significantly depending on which imaging technique is used. A comparison of four methods found that the Dunn 45-degree radiograph yielded the highest alpha angle (averaging about 66 degrees), significantly greater than the Dunn 90-degree view (about 58 degrees), MRI (about 53 degrees), and CT (about 55 degrees). Because of this, the Dunn 45-degree radiograph has been recommended as the most sensitive screening tool for cam morphology.15PubMed. Comparison of MRI, CT, Dunn 45° and Dunn 90° alpha angle measurements in femoroacetabular impingement
For pincer morphology, radiographs look for signs of excessive acetabular coverage: a crossover sign on the AP pelvis, a positive posterior wall sign, or evidence of acetabular protrusion. These markers can be subtle and depend on how well the pelvis is positioned during the X-ray.
MRI and MR Arthrography
When clinicians need to see the soft tissue damage caused by FAI, especially labral tears and cartilage injuries, MRI is the standard next step. Conventional MRI at 3 Tesla picks up labral tears with sensitivity around 88–90% when compared to arthroscopic findings.16PubMed Central. Comparison of 3.0-T MR vs 3.0-T MR arthrography of the hip for detection of acetabular labral tears and chondral defects in the same patient population MR arthrography, where contrast is injected directly into the hip joint before scanning, tends to perform slightly better, particularly for cartilage damage. A meta-analysis found that MR arthrography had a sensitivity of 87% and conventional MRI had a sensitivity of 66% for labral tears, though the MRA specificity (64%) was actually lower than that of unenhanced MRI (79%).17PubMed. The diagnostic accuracy of acetabular labral tears using magnetic resonance imaging and magnetic resonance arthrography: a meta-analysis
A review of the radiologic literature concluded that direct MR arthrography is overall the preferred imaging method for detecting labral and cartilage abnormalities in the hip.18PubMed. MRI of Labral and Chondral Lesions of the Hip That said, the injection itself adds discomfort, cost, and a small amount of radiation exposure from the fluoroscopic guidance used to place the needle. Many clinicians reserve MR arthrography for cases where conventional MRI leaves the picture unclear or when surgical planning requires more detailed soft-tissue information.
Diagnostic Injections
When the clinical picture is still ambiguous after physical examination and imaging, a diagnostic injection can help localize the source of pain. A numbing agent (sometimes combined with a corticosteroid) is injected directly into the hip joint under image guidance. If the injection substantially reduces your pain, that confirms the hip joint itself as the pain generator, which supports the diagnosis of an intra-articular problem like FAI.
One review found that local anesthetic injections relieved pain in about 93% of patients, and corticosteroid injections provided relief ranging from roughly 61% to 82%.19PubMed. Outcomes After Diagnostic Hip Injection The injection also carries prognostic value: patients who do not respond to the injection tend to have worse outcomes if they proceed to surgery, making a failed injection a meaningful red flag before committing to an operation.20PubMed. Outcomes After Diagnostic Hip Injection
The evidence on injection accuracy is mixed, though. A systematic review focused specifically on FAI found that two of four included studies reported high diagnostic accuracy for intra-articular injections, while the other two found limited ability to distinguish FAI from healthy hips or other conditions. All the studies were judged to be at risk of bias, and there was substantial variation in how researchers defined a “positive” response.21Clinical Journal of Sport Medicine. Diagnostic Capability of Intra-Articular Injections for Femoroacetabular Impingement Syndrome: A Systematic Review So while a clearly positive or negative injection response is useful, borderline results still leave room for uncertainty.
Why Imaging Alone Does Not Diagnose FAI Syndrome
One of the most common misunderstandings about FAI is that seeing cam or pincer morphology on an X-ray or MRI means you have FAI syndrome. In reality, these bony shapes are surprisingly common in people who have no hip pain at all. A population-based study of over 2,000 healthy young adults found cam-type features in up to 22% of men and pincer-related findings in over half of men when looking at crossover signs on AP pelvis X-rays.22PubMed. Prevalence of radiographic findings thought to be associated with femoroacetabular impingement in a population-based cohort of 2081 healthy young adults A study of asymptomatic hips in an Indian population found that about 15% of radiographs showed features of FAI.23International Journal of Research in Orthopaedics. The prevalence of femoroacetabular impingement in asymptomatic hips in Indian population: a radiomorphometric analysis Cam and pincer morphology is highly prevalent across different ages, sexes, ethnicities, and levels of athletic activity.24PubMed. The Prevalence of Cam and Pincer Morphology and Its Association With Development of Hip Osteoarthritis
This is why the 2016 Warwick Agreement, an international consensus statement, emphasized that diagnosing FAI syndrome requires the combination of symptoms, clinical signs, and imaging findings. Yet a scoping review of surgical studies found that only 56% used all three criteria together.25British Journal of Sports Medicine. Surgical criteria for femoroacetabular impingement syndrome: a scoping review The practical takeaway for patients: if your imaging shows cam or pincer morphology but you have no symptoms and normal physical exam findings, that alone is not a reason for treatment.
Functional Movement Tests
Beyond the exam table, some clinicians use dynamic tasks like squatting to assess how FAI affects real-world movement. Research has found that biomechanical differences between people with FAI syndrome and those without hip pain become more pronounced during a single-leg squat compared to a two-legged squat.26PubMed. Hip Biomechanics During a Single-Leg Squat: 5 Key Differences Between People With Femoroacetabular Impingement Syndrome and Those Without Hip Pain People with FAI also tend to have slower squat velocities and slower sit-to-stand times, along with altered hip mechanics during walking.27PubMed Central. Physical Examination of the Hip: Assessment of Femoroacetabular Impingement, Labral Pathology, and Microinstability
A recently developed tool called SIMPLI-FAI attempts to standardize single-leg squat assessment for this population. It uses six yes-or-no questions about overall and segmental movement quality, and initial testing showed adequate reliability and content validity.28JOSPT Open. Is It Time to SIMPLI-FAI? Development of the SIngle-Leg Squat Movement Performance scaLe for Individuals With FemoroAcetabular Impingement Syndrome Codesigned With End Users Tools like this are more commonly used in rehabilitation settings to track progress than as primary diagnostic instruments, but they reflect the broader trend of evaluating how FAI affects function, not just anatomy.
Conditions That Mimic FAI
Groin and hip pain have a long list of potential sources, and several conditions produce symptoms that overlap with FAI. Athletic pubalgia (sometimes called a sports hernia) is a particularly important mimic because it frequently coexists with FAI. Research suggests FAI is present in anywhere from 12% to 94% of patients with sports hernias or adductor-related groin pain. The proposed link is mechanical: a cam deformity may increase motion at the pubic symphysis, overloading the soft tissues around the groin. When both problems are present, addressing both surgically has led to better outcomes than treating either one alone.29PubMed Central. Sports hernia and femoroacetabular impingement in athletes: A systematic review
Deep gluteal syndrome is another diagnostic trap. Pain that seems to come from the hip can actually originate from irritation of the sciatic nerve in the buttock, from hamstring tendon problems, or from ischiofemoral impingement (pinching of soft tissue between two pelvic bones). These conditions share overlapping symptoms with FAI but can often be sorted out through careful examination and strategically placed diagnostic injections.30Journal of the American Academy of Orthopaedic Surgeons. Deep Gluteal Pain in Orthopaedics: A Challenging Diagnosis
What a Positive Test Means for Treatment
Getting a positive FADIR or a confirming set of imaging findings does not automatically point you toward surgery. Physical therapy has shown meaningful short-term benefits for FAI. A meta-analysis found moderate to large improvements in both pain and function with conservative treatment.31PubMed Central. Short-Term Outcomes of Conservative Treatment for Femoroacetabular Impingement: A Systematic Review and Meta-Analysis One clinical study that started all patients on conservative management found that after an average follow-up of about two and a half years, roughly 55% of hips could perform normal daily activities without needing surgery. The other 45% eventually had arthroscopic surgery, which also led to significant improvement.32PubMed Central. Clinical Outcomes of an Initial 3-month Trial of Conservative Treatment for Femoroacetabular Impingement
Conservative management typically involves activity modification, strengthening of the hip and core muscles, and manual therapy to improve joint mechanics. For many people, especially those with mild symptoms or who are not trying to return to high-level sport, this approach is a reasonable first step before considering surgery. The diagnostic injection plays a dual role here: if a hip injection relieves your pain, it both confirms the diagnosis and tells the surgical team that the joint is likely to respond well to arthroscopy. If it does not help, reconsidering the diagnosis or expecting a less favorable surgical outcome is warranted.
Patient-Reported Outcome Questionnaires
Part of the testing process for FAI, especially when deciding about surgery or tracking progress, involves standardized questionnaires that ask you to rate your pain, stiffness, and ability to do various activities. A reliability study of six commonly used hip questionnaires found that most reached acceptable consistency when used to track groups of patients, with measurement error at the group level staying small. At the individual level, however, the amount of change needed to be confident a real improvement had occurred (as opposed to just measurement noise) was much larger, ranging from about 12 to 36 points on a 100-point scale.33BMJ Journals. Which is the most useful patient-reported outcome in femoroacetabular impingement? Test–retest reliability of six questionnaires For patients, this means that a small shift in your questionnaire score after treatment may not reflect a real change in your hip, and clinicians need to see a fairly large improvement before concluding that an intervention worked.