What is the initial examination and imaging protocol for a labral tear?

Initial Examination and Imaging Protocol for Labral Tear

MR arthrography is the gold standard for diagnosing labral tears, with a rating of 9/9 (usually appropriate) according to ACR Appropriateness Criteria. 1, 2

Clinical Examination

• The most consistent physical examination finding for labral tears is a positive anterior hip impingement test (FADIR test) 3
• Common clinical presentations include:
  • Anterior hip or groin pain (most common) 4
  • Mechanical symptoms including clicking, locking, and giving way 5
  • Buttock pain (less common) 5
• Specific clinical tests with moderate diagnostic value:
  • O'Brien test (63% sensitive, 73% specific) 6
  • Jobe relocation test (44% sensitive, 87% specific) 6
  • Apprehension test (approaching statistical significance) 6
• Using all three tests together and accepting a positive result for any increases sensitivity to 72% and specificity to 73% 6
• Note that clinical testing alone is not sufficient for definitive diagnosis of labral tears 6

Initial Imaging Protocol

• Plain radiographs should be the first imaging study for any acute shoulder pain 1

  • Standard views should include:
    • Frontal (anteroposterior) view 1
    • At least two orthogonal views for trauma cases 1
    • Grashey projection (30° posterior oblique) to profile the glenohumeral joint 1

• For suspected labral tears with negative or indeterminate radiographs in patients under 35 years:

  • MR arthrography is the preferred imaging study (rating 9/9) 1
  • Standard MRI without contrast is less optimal (rating 7/9) 1
  • CT arthrography is an alternative (rating 5/9) if MRI is contraindicated 1

Advanced Imaging Considerations

• MR arthrography with intra-articular injection of dilute gadolinium solution provides superior visualization compared to standard MRI 1, 7
• MR arthrography shows superior sensitivity for:
  • Detecting labral tears (96% vs 93% for standard MRI) 7
  • Identifying detached labral fragments (96% vs 46% for standard MRI) 7
  • Visualizing labral degeneration (56% vs 11% for standard MRI) 7
• In acute trauma settings, standard MRI may be sufficient as posttraumatic joint effusion can provide natural contrast 1
• High-resolution 3T MRI may improve visualization in some cases 2

Important Considerations and Pitfalls

• Diagnosis should never be based on imaging alone but should integrate clinical examination, imaging findings, and patient symptoms 3
• Labral tear patterns are highly variable - ten distinct patterns have been identified 8
• Posterior labral tears (47.9% of cases) are more common than previously recognized and typically present with pain rather than instability 8
• Anterior labral tears (25.7% of cases) more commonly present with instability 8
• Combined anterior-posterior tears account for 26.4% of cases 8
• Accurate preoperative diagnosis by both radiologists and surgeons occurs in only 30% of cases 8

Diagnostic Algorithm

1. Begin with plain radiographs to rule out fractures, dysplasia, and degeneration 1, 5
2. Perform clinical examination with specific tests (O'Brien, Jobe relocation, apprehension) 6
3. For patients under 35 with suspected labral tear, proceed to MR arthrography 1
4. For patients with acute trauma, standard MRI may be sufficient due to natural joint effusion 1
5. Consider diagnostic intra-articular anesthetic injections for both diagnostic and therapeutic purposes 2, 3