What are the steps for a physical exam for a suspected meniscus injury?

Physical Examination for Meniscus Injury

The most effective physical examination for a suspected meniscus injury should include joint line tenderness assessment, McMurray's test, Apley's test, and the Thessaly test, as these tests in combination provide the highest diagnostic accuracy when compared to arthroscopic findings. 1, 2

Initial Assessment

1. Compare with uninjured knee first - Always examine the uninjured knee first to establish a baseline for comparison 3

2. Joint Line Tenderness

   • Palpate along the medial and lateral joint lines with the knee flexed to 90°
   • Positive finding: Pain along the joint line
   • Sensitivity: 70-73%, Specificity: 53-67% 2

3. McMurray's Test

   • Position: Patient supine with knee fully flexed
   • Technique:
     • For medial meniscus: Externally rotate the foot while extending the knee
     • For lateral meniscus: Internally rotate the foot while extending the knee
   • Positive finding: Audible/palpable click or pain during the maneuver
   • Sensitivity: 69-80%, Specificity: 73-75% 2

4. Apley's Grind Test

   • Position: Patient prone with knee flexed to 90°
   • Technique: Apply downward pressure on the foot while rotating the tibia
   • Positive finding: Pain during rotation
   • Sensitivity: 65-69%, Specificity: 70% 2

5. Thessaly Test

   • Position: Patient standing on one leg with knee flexed at 20°
   • Technique: Patient rotates body internally and externally while maintaining weight on the affected leg
   • Positive finding: Pain or locking sensation
   • Sensitivity: 70-73%, Specificity: 75-77% 2

6. Bounce Home Test

   • Position: Patient supine with examiner holding the heel
   • Technique: Fully flex the knee, then allow it to passively extend
   • Positive finding: Lack of smooth, complete extension 3

Composite Testing Approach

Research shows that using a composite approach with at least two positive tests significantly improves diagnostic accuracy:

• Medial meniscus: Sensitivity 85%, Specificity 73.3%, Accuracy 78% 2
• Lateral meniscus: Sensitivity 92.3%, Specificity 87.5%, Accuracy 90% 2

Additional Assessment Elements

• Range of Motion Testing - Both passive and active 3
• Effusion Assessment - Check for joint swelling
• Stability Testing - Assess for associated ligament injuries:
  • Valgus/varus stress tests for collateral ligaments
  • Lachman and pivot shift tests for anterior cruciate ligament
  • Posterior drawer test for posterior cruciate ligament 3

Common Pitfalls and Considerations

• The "Duck Walk" test (squatting and waddling) has poor specificity (39%) and should not be used alone for diagnosis 4
• Physical examination tests individually have limited diagnostic accuracy, with sensitivities ranging from 60-80% and specificities from 53-77% 5
• Medial meniscus tears are more common due to attachment to the medial collateral ligament 6
• Older patients may present without a specific injury mechanism due to degenerative processes 6

Next Steps After Physical Examination

If meniscal injury is suspected based on physical examination:

• MRI is the gold standard for confirmation (sensitivity 96%, specificity 97%) 1
• Initial radiographs (X-rays) should be performed to rule out fractures 1

Remember that while physical examination is essential for initial assessment, MRI remains necessary for definitive diagnosis, especially when meniscal injuries are associated with cruciate ligament injuries 2.