Hip Femoroacetabular Impingement Examination
FAI examination focuses on reproducing impingement symptoms through provocative testing. The FADIR test (anterior impingement test) is most sensitive. Examiners expect you to understand cam vs pincer morphology, recognize the typical presentation in young active patients, and differentiate from other causes of hip pain.
Quick Reference One-Pager
Key Presentation
- Young active patient (20-40 years)
- Groin pain (anterior)
- Pain with prolonged sitting, squatting
- Mechanical symptoms (clicking, catching)
- C-sign: Patient cups hand around hip/groin
Provocative Tests
- FADIR (anterior impingement) - most sensitive
- FABER (posteroinferior)
- Log roll (irritability)
- Fitzgerald test (dynamic)
- Internal rotation in flexion limited
Cam vs Pincer
- Cam: Young male, aspherical femoral head, IR limited
- Pincer: Middle-aged female, over-covered acetabulum
- Combined: Most common (86%)
Imaging
- AP pelvis + Dunn 45° lateral
- Alpha angle (cam greater than 55°)
- MRA for labral tears
- CT for bony morphology
Pathophysiology
Understanding FAI
Femoroacetabular Impingement:
- Abnormal contact between femoral head-neck and acetabulum
- Occurs at extremes of motion (flexion, internal rotation)
- Causes labral tears and chondral damage
- May progress to early osteoarthritis if untreated
Types of FAI:
- Morphology
- Aspherical femoral head-neck
- Demographics
- Young males, athletes
- Pathoanatomy
- Bump on anterior head-neck junction shears into acetabulum
- Morphology
- Over-covered acetabulum
- Demographics
- Middle-aged females
- Pathoanatomy
- Labrum crushed between rim and femoral neck
- Morphology
- Both cam and pincer
- Demographics
- Most common (86%)
- Pathoanatomy
- Both mechanisms
Alpha Angle:
- Measured on lateral X-ray (Dunn view) or MRI
- Normal: less than 50-55°
- Cam morphology: greater than 55°
- Higher angle = larger bump = more impingement
Clinical Presentation
History Clues
Typical Patient:
- Young adult (20-40 years)
- Active/athletic
- Groin pain (anterior, may radiate to lateral thigh)
- No history of trauma (insidious onset)
Aggravating Factors:
- Prolonged sitting (e.g., driving, desk work)
- Squatting, deep flexion activities
- Pivoting, twisting movements
- Getting in/out of car
C-Sign:
- Patient cups hand around anterolateral hip/groin
- Indicates deep anterior hip pain
- Classic sign of intra-articular hip pathology
Physical Examination
Range of Motion
ROM Assessment
Key Findings in FAI:
- Internal rotation limited (especially in 90° flexion)
- Compare with opposite side
- Normal IR in flexion: 30-45°
- FAI: Often less than 15-20° IR
Flexion:
- May be limited (normally 120°)
- Pain at end range as impingement occurs
DEXRIT and DIRI:
- DEXRIT: Decreased External Rotation In Extension
- DIRI: Decreased Internal Rotation (in flexion)
- Both suggest intra-articular pathology
Provocative Tests
Special test
FADIR Test (Anterior Impingement Test)
Femoroacetabular impingement, labral tear
Technique
- 1Patient supine
- 2Hip flexed to 90°
- 3Adduct hip across midline
- 4Internally rotate the hip
Positive Sign
Groin pain reproduced
Indicates
Anterior/anterosuperior impingement, labral pathology (most sensitive FAI test)
Diagnostic Accuracy
Ability to detect true positives
Ability to exclude false positives
FADIR Test Interpretation:
- Highly sensitive but NOT specific
- A negative FADIR essentially rules out FAI
- A positive FADIR requires further evaluation (imaging) to confirm
- Pain should be in the groin (not trochanteric)
Special test
FABER Test (Patrick's Test)
Hip pathology, SI joint
Technique
- 1Patient supine
- 2Flex, ABduct, Externally Rotate hip
- 3Place ankle on opposite knee (figure-4 position)
- 4Gently push down on knee
Positive Sign
Groin pain = hip pathology. Posterior pain = SI joint pathology
Indicates
Hip pathology (OA, FAI, labral tear) or SI joint dysfunction
Diagnostic Accuracy
Ability to detect true positives
Ability to exclude false positives
Special test
Log Roll Test
Hip joint irritability
Technique
- 1Patient supine, leg extended and relaxed
- 2Roll the leg gently in internal and external rotation
- 3Only rotation occurs at hip (no flexion/extension)
Positive Sign
Pain or apprehension with rotation
Indicates
Hip joint irritability (any intra-articular pathology: FAI, OA, infection, AVN)
Diagnostic Accuracy
Ability to detect true positives
Ability to exclude false positives
Special test
Fitzgerald Test (Dynamic Impingement)
Differentiate anterior vs posterior labral tear
Technique
- 1ANTERIOR: Hip flexed, externally rotated, then extend while internally rotating
- 2POSTERIOR: Hip extended, internally rotated, then flex while externally rotating
Positive Sign
Pain or click during maneuver
Indicates
Anterior test positive = anterior labral tear (more common). Posterior test positive = posterior labral tear
Diagnostic Accuracy
Ability to detect true positives
Ability to exclude false positives
Special test
Internal Rotation Over Pressure (IROP)
Anterior impingement
Technique
- 1Patient supine, hip flexed to 90°
- 2Apply internal rotation force at end range
- 3Add slight adduction
Positive Sign
Groin pain reproduced
Indicates
Anterior impingement, similar to FADIR
Diagnostic Accuracy
Ability to detect true positives
Ability to exclude false positives
Special test
Posterior Impingement Test
Posterior FAI (less common)
Technique
- 1Patient supine at edge of bed
- 2Affected hip in extension off edge
- 3Apply external rotation force
Positive Sign
Posterior hip/buttock pain
Indicates
Posterior impingement (rare, seen in posterior pincer)
Diagnostic Accuracy
Ability to detect true positives
Ability to exclude false positives
Additional Tests
Special test
Resisted Straight Leg Raise (Stinchfield)
Intra-articular hip pathology
Technique
- 1Patient supine, knee extended
- 2Lift leg to 30° against resistance
- 3Note location of pain
Positive Sign
Groin pain reproduced
Indicates
Intra-articular hip pathology (flexor compartment loading)
Diagnostic Accuracy
Ability to detect true positives
Ability to exclude false positives
Special test
Scour Test (Flexion-Adduction-Compression)
Labral or chondral pathology
Technique
- 1Patient supine, hip flexed to 90°
- 2Apply axial compression through femur while circumducting hip
- 3Rotate through flexion, adduction, extension, abduction
Positive Sign
Pain, clicking, or catching during motion
Indicates
Labral tear or chondral defect
Diagnostic Accuracy
Ability to detect true positives
Ability to exclude false positives
Differential Diagnosis
- presentation
- Young, groin pain, activity-related
- tests
- FADIR +, limited IR in flexion
- imaging
- Cam/pincer on X-ray, MRA labral tear
- presentation
- Older, groin pain, stiffness
- tests
- Global ROM loss, groin pain
- imaging
- Joint space narrowing, osteophytes
- presentation
- Clicking, mechanical symptoms
- tests
- Scour test +
- imaging
- MRA best
- presentation
- Lateral hip pain
- tests
- Greater trochanter tender, FABER lateral pain
- imaging
- Usually clinical diagnosis
- presentation
- Groin pain, snapping
- tests
- Resisted hip flexion painful
- imaging
- Ultrasound/MRI
- presentation
- Groin pain, athletes
- tests
- Pubic symphysis tender, resisted sit-up
- imaging
- MRI pelvis
Cam vs Pincer Clinical Differentiation
- cam
- Young males, athletes
- pincer
- Middle-aged females
- cam
- Aspherical head-neck junction
- pincer
- Over-covered acetabulum
- cam
- IR most limited
- pincer
- May have global restriction
- cam
- Anterosuperior chondral damage (outside-in)
- pincer
- Labral crush, circumferential damage
- cam
- Pistol grip deformity, alpha angle elevated
- pincer
- Crossover sign, protrusio
- cam
- Higher risk of OA progression
- pincer
- May be more indolent
Summary Presentation
“28-year-old male recreational footballer with 12-month history of right groin pain, worse with prolonged sitting and squatting.”
Examination Sequence
Systematic Approach
- Observation: Gait, leg length, muscle bulk
- C-sign: Ask patient to show where it hurts
- ROM: Compare flexion, IR, ER bilaterally
- Log roll: Assess irritability
- FADIR: Key test for anterior impingement
- FABER: Assess posteroinferior and SI joint
- Fitzgerald: Dynamic impingement if positive above
- Stinchfield: Confirm intra-articular pathology
- Trochanteric palpation: Exclude lateral causes
- Lumbar spine: Exclude referred pain
Examiner Tips
Do
- Perform FADIR correctly (flex, adduct, internally rotate)
- Quantify internal rotation and compare sides
- Ask about C-sign
- Differentiate cam vs pincer conceptually
- Mention imaging (alpha angle, MRA)
Don't
- Forget to examine lumbar spine
- Miss the log roll test for irritability
- Confuse FADIR with FABER
- Ignore lateral hip pathology in differential
- Accept pain anywhere as positive FADIR (must be groin)