Focused examination for femoroacetabular impingement (FAI) including FADIR, FABER testing, and differentiation of cam vs pincer morphology.
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.
High-Yield Exam Summary
Femoroacetabular Impingement:
Types of FAI:
| Type | Morphology | Demographics | Pathoanatomy |
|---|---|---|---|
| Cam | Aspherical femoral head-neck | Young males, athletes | Bump on anterior head-neck junction shears into acetabulum |
| Pincer | Over-covered acetabulum | Middle-aged females | Labrum crushed between rim and femoral neck |
| Combined | Both cam and pincer | Most common (86%) | Both mechanisms |
Alpha Angle:
Typical Patient:
Aggravating Factors:
C-Sign:
Key Findings in FAI:
Flexion:
DEXRIT and DIRI:
Femoroacetabular impingement, labral tear
Groin pain reproduced
Anterior/anterosuperior impingement, labral pathology (most sensitive FAI test)
Ability to detect true positives
Ability to exclude false positives
FADIR Test Interpretation:
Hip pathology, SI joint
Groin pain = hip pathology. Posterior pain = SI joint pathology
Hip pathology (OA, FAI, labral tear) or SI joint dysfunction
Ability to detect true positives
Ability to exclude false positives
Hip joint irritability
Pain or apprehension with rotation
Hip joint irritability (any intra-articular pathology: FAI, OA, infection, AVN)
Ability to detect true positives
Ability to exclude false positives
Differentiate anterior vs posterior labral tear
Pain or click during maneuver
Anterior test positive = anterior labral tear (more common). Posterior test positive = posterior labral tear
Ability to detect true positives
Ability to exclude false positives
Anterior impingement
Groin pain reproduced
Anterior impingement, similar to FADIR
Ability to detect true positives
Ability to exclude false positives
Posterior FAI (less common)
Posterior hip/buttock pain
Posterior impingement (rare, seen in posterior pincer)
Ability to detect true positives
Ability to exclude false positives
Intra-articular hip pathology
Groin pain reproduced
Intra-articular hip pathology (flexor compartment loading)
Ability to detect true positives
Ability to exclude false positives
Labral or chondral pathology
Pain, clicking, or catching during motion
Labral tear or chondral defect
Ability to detect true positives
Ability to exclude false positives
| condition | presentation | tests | imaging |
|---|---|---|---|
| FAI | Young, groin pain, activity-related | FADIR +, limited IR in flexion | Cam/pincer on X-ray, MRA labral tear |
| Hip OA | Older, groin pain, stiffness | Global ROM loss, groin pain | Joint space narrowing, osteophytes |
| Labral Tear (no FAI) | Clicking, mechanical symptoms | Scour test + | MRA best |
| Trochanteric Bursitis | Lateral hip pain | Greater trochanter tender, FABER lateral pain | Usually clinical diagnosis |
| Iliopsoas Tendinitis | Groin pain, snapping | Resisted hip flexion painful | Ultrasound/MRI |
| Athletic Pubalgia | Groin pain, athletes | Pubic symphysis tender, resisted sit-up | MRI pelvis |
| feature | cam | pincer |
|---|---|---|
| Demographics | Young males, athletes | Middle-aged females |
| Pathology | Aspherical head-neck junction | Over-covered acetabulum |
| ROM Pattern | IR most limited | May have global restriction |
| Damage Pattern | Anterosuperior chondral damage (outside-in) | Labral crush, circumferential damage |
| X-ray Finding | Pistol grip deformity, alpha angle elevated | Crossover sign, protrusio |
| Natural History | Higher risk of OA progression | May be more indolent |
"28-year-old male recreational footballer with 12-month history of right groin pain, worse with prolonged sitting and squatting."
High-Yield Exam Summary