import { HighYieldBox, ExamCheatSheet, Tabs, Tab, ComparisonTable, VivaScenario, ContentSection, SpecialTestCard , MedicalImage} from '@/components/content' # 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 ## Pathophysiology **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:** | 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:** - 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 **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 **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 **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) ### Additional Tests ## Differential Diagnosis ## Cam vs Pincer Clinical Differentiation ## Summary Presentation ## Examination Sequence 1. **Observation**: Gait, leg length, muscle bulk 2. **C-sign**: Ask patient to show where it hurts 3. **ROM**: Compare flexion, IR, ER bilaterally 4. **Log roll**: Assess irritability 5. **FADIR**: Key test for anterior impingement 6. **FABER**: Assess posteroinferior and SI joint 7. **Fitzgerald**: Dynamic impingement if positive above 8. **Stinchfield**: Confirm intra-articular pathology 9. **Trochanteric palpation**: Exclude lateral causes 10. **Lumbar spine**: Exclude referred pain ## Examiner Tips