Meniscal Extrusion Measurements After Posterior Medial Meniscus Root Tears: A Systematic Review and Meta-analysis

Area of Science:

• Orthopedics
• Radiology
• Biomedical Engineering

Background:

• Meniscal extrusion is increasingly used to assess meniscus root abnormalities.
• No standardized definition or measurement approach currently exists for meniscal extrusion.

Approach:

• Systematic review of 45 studies evaluating meniscal extrusion in posterior medial meniscus root tears (PMMRTs).
• Included clinical and cadaveric studies reporting quantitative extrusion data.
• Excluded studies lacking full extension data, semiquantitative analyses, or comparative data only.

Key Points:

• Magnetic resonance imaging was the predominant imaging modality (89%).
• Common landmarks for coronal imaging included the medial collateral ligament (38%), meniscus midpoint (23%), and medial femoral condyle (19%).
• Pooled mean meniscal extrusion was 3.2 ± 2.0 mm, with variations based on measurement location.

Conclusions:

• Significant heterogeneity exists in meniscal extrusion measurement techniques, particularly reference points.
• Further research should focus on clear descriptions and uniform methodologies for meniscal extrusion measurements.
• Standardization will enable better comparison and pooling of data across studies.