How to differentiate and treat a labral tear versus Femoroacetabular Impingement (FAI) syndrome?

Differentiating and Treating Labral Tear vs Femoroacetabular Impingement (FAI) Syndrome

For optimal patient outcomes in terms of morbidity, mortality, and quality of life, diagnosis and treatment should integrate clinical examination, imaging findings, and patient symptoms, as neither labral tears nor FAI syndrome should be diagnosed based on imaging alone.1

Diagnostic Differentiation

Clinical Examination

• A negative flexion adduction internal rotation (FADIR) test helps rule out both conditions, while a positive test may indicate either condition but has limited diagnostic specificity 1
• Restricted internal hip rotation in 0° hip flexion with or without pain suggests FAI syndrome (though with low diagnostic effectiveness) 2
• No pain in FADIR test or no restricted range of motion in Flexion Abduction External Rotation test compared to the unaffected side may help rule out FAI syndrome 2
• Slow-onset, persistent groin pain is the most common presenting symptom for FAI syndrome 3
• Common symptoms for both conditions include pain, clicking, catching, buckling, stiffness, giving way, and limited hip range of motion 4

Imaging

• Initial diagnostic imaging should include anteroposterior (AP) pelvis and lateral femoral head-neck radiographs 1
• For labral tears, MR arthrography is superior to CT arthrography and non-contrast MRI 1
• For FAI syndrome, radiographs can measure alpha angle and lateral center edge angle to quantify severity 3
• Advanced imaging (MRI/MRA or CT) should be used when three-dimensional morphological assessment is needed or to evaluate intra-articular structures like the labrum, cartilage, and ligamentum teres 1
• Caution: Incidental intra-articular findings are common in asymptomatic individuals 1

Classification After Imaging

Hip-related pain may be categorized into three main conditions 1:

1. FAI syndrome - characterized by specific bony morphology
2. Acetabular dysplasia and/or hip instability
3. Other conditions causing hip-related pain (including isolated labral tears) - soft-tissue conditions without specific bony morphology

Treatment Approaches

Conservative Management

• Initial treatment for both conditions should be conservative 4

• Prescribed physiotherapy consisting of:

  • Hip strengthening
  • Hip joint manual therapy techniques
  • Functional activity-specific retraining
  • Education

  This approach shows a small to medium effect size compared to passive modalities, stretching, and advice alone 2

• Intra-articular injections can be both diagnostic and therapeutic 1, 4

• Activity modification may help reduce symptoms 4

Surgical Management

• Hip arthroscopy is currently the preferred surgical management for both conditions 5, 4
• For FAI syndrome, arthroscopy aims to:
  • Correct bony abnormalities
  • Repair or reconstruct labral lesions
  • Address other intra-articular and extra-articular derangements 4
• Hip arthroscopy shows superior outcomes compared to prescribed physiotherapy for FAI syndrome (small effect size; moderate quality of evidence) 2
• Surgical intervention has demonstrated excellent results for moderate to severe cases 3

Important Considerations and Pitfalls

• Never diagnose based on imaging alone - diagnosis should combine clinical signs, symptoms, and imaging findings 1
• Beware of incidental findings - labral, chondral, and ligamentum teres pathology are common on imaging in asymptomatic people 1
• Limited diagnostic accuracy of physical tests - current physical tests have low diagnostic accuracy and validity for confirming or discarding FAI and/or labral pathology 6
• Consider coexisting conditions - many hip-related pain conditions, especially labral and chondral conditions, coexist with FAI syndrome 1
• Exclude other causes - both non-musculoskeletal and serious hip pathological conditions (tumors, infections, stress fractures) and competing musculoskeletal conditions (lumbar spine) should be excluded 1