What special tests are likely to be positive for a suspected hip labral tear?

Hip Labral Tear Special Testing: Diagnostic Approach

The FADIR (Flexion-Adduction-Internal Rotation) test is the most appropriate clinical special test for detecting hip labral tears, though it has limited diagnostic accuracy when used alone.

Primary Special Tests for Hip Labral Tears

FADIR Test (Most Recommended)

• Performed by flexing the hip to 90°, adducting, and internally rotating the hip
• Considered the primary screening test for hip-related pain 1
• Positive test reproduces the patient's pain
• Limitations:
  • Limited specificity (can be positive in other hip conditions)
  • Sensitivity of 43% and specificity of 56% when used alone 2

Arlington Test (High Sensitivity)

• Novel test with superior sensitivity compared to traditional FADIR
• Technique: Range the hip from flexion-abduction-external rotation to FADIR while applying subtle internal/external rotation motion
• Diagnostic value:
  • Sensitivity: 94% (significantly higher than FADIR)
  • Specificity: 33%
  • Positive predictive value: 95% 2

Twist Test (High Specificity)

• Novel test with better specificity than FADIR
• Technique: Internal rotation and external rotation of the hip while weightbearing
• Diagnostic value:
  • Sensitivity: 68%
  • Specificity: 72% (significantly higher than Arlington test)
  • Positive predictive value: 97% 2

Additional Supportive Tests

FABER Test

• Flexion, Abduction, and External Rotation of the hip
• Positive in approximately 71% of patients with labral tears 3
• Moderate interrater reliability (κ = 0.63) 4

McCarthy Test

• Patient supine, examiner extends and externally rotates the hip from a flexed position
• Positive in approximately 43% of patients with labral tears 3

Scour Test

• Combines hip flexion, adduction with circumduction
• Useful for detecting labral tears 5

Diagnostic Algorithm

1. Initial Screening: Perform FADIR test as primary screening tool

   • If positive, proceed with additional special tests
   • If negative, consider other sources of hip pain (FADIR has high negative predictive value)

2. Confirmatory Testing: Combine multiple tests for improved accuracy

   • Arlington test (for high sensitivity)
   • Twist test (for high specificity)
   • FABER test (as supplementary test)

3. Imaging Confirmation: If special tests suggest labral tear

   • First imaging: Plain radiographs of pelvis and hip 1
   • If radiographs negative/equivocal: MR arthrography (gold standard, rated 9/9 for suspected labral tears) 1, 6
   • Alternative: High-resolution 3T MRI without contrast may be sufficient 6

Clinical Considerations

• No single test has perfect diagnostic accuracy; combining multiple tests improves diagnostic yield 1, 2
• Clinical diagnosis should never be made on special tests alone but combined with:
  • Patient symptoms (typically anterior hip or groin pain)
  • Imaging findings 1, 6
• Incidental labral tears are common in asymptomatic individuals and should be managed with appropriate clinical sensitivity 6
• Special tests may be affected by coexisting conditions like femoroacetabular impingement (FAI) 3, 5

Common Pitfalls to Avoid

• Relying on a single special test for diagnosis (combine multiple tests)
• Making diagnosis based solely on imaging without correlating with clinical findings 1, 6
• Failing to consider other causes of hip pain that may produce similar symptoms
• Not performing tests with proper technique, which can lead to false results
• Overlooking associated conditions like FAI that frequently coexist with labral tears 3

By systematically applying these special tests in combination with appropriate imaging, clinicians can improve their diagnostic accuracy for hip labral tears and guide appropriate treatment decisions.