Lateral Meniscus Tears Are More Common in Acute ACL Injuries
Yes, the assertion is correct - lateral meniscus tears are more common than medial meniscus tears in acute ACL injuries, as confirmed by modern MRI studies and surgical findings.
Prevalence of Meniscal Tears in ACL Injuries
- Meniscal tears are frequently associated with ACL injuries, occurring in 21-66% of cases 1
- In acute ACL injuries:
- In chronic ACL injuries (>8 weeks post-injury):
- The pattern shifts, with medial meniscus tears becoming more common
- Bilateral meniscal tears increase significantly (41.4% in chronic cases vs 19.9% in acute cases) 2
Types of Lateral Meniscus Tears in Acute ACL Injuries
- Lateral meniscus oblique radial tears (LMORTs) of the posterior horn are particularly common:
- Found in 12% of all acute ACL injuries
- Represent 18% of all meniscal tears associated with acute ACL injuries 3
- Other common lateral meniscus tear patterns include:
- Root tears
- Vertical tears
- Bucket handle tears (though less common in lateral meniscus compared to medial) 2
Diagnostic Considerations
- MRI is the gold standard for diagnosing meniscal tears associated with ACL injuries 4
- MRI diagnostic performance varies by meniscus location:
- Higher sensitivity for medial meniscus tears (90%)
- Lower sensitivity for lateral meniscus tears (67%) 5
- Timing matters for MRI accuracy:
- Higher diagnostic performance for lateral meniscus tears when surgery is performed within 30 days of imaging 5
- False positives and negatives can occur, requiring careful clinical correlation
Clinical Implications
- Recognition of lateral meniscus tears in acute ACL injuries is crucial for proper management
- Untreated meniscal tears can lead to:
- Increased rotational laxity
- Meniscal extrusion
- Higher risk of progressive osteoarthritic degeneration 1
- Early ACL reconstruction is recommended to prevent secondary meniscal tears, particularly medial meniscus tears that develop in chronic cases 2
Treatment Considerations
- Meniscal repair at the time of ACL reconstruction is increasingly recommended to:
- Restore knee biomechanics
- Reduce the risk of osteoarthritic changes 1
- Patients with lateral meniscus injuries treated during ACL reconstruction may have:
- Higher odds of meniscal injuries at time of ACL revision surgery
- Higher odds of cartilage injuries if meniscectomy was performed 6
Understanding this pattern of lateral meniscus predominance in acute ACL injuries is clinically relevant for surgical planning and can indeed be a valuable point to know for both examinations and clinical practice.