Evaluation of Medial Meniscal Extrusion Using Radiography

Area of Science:

• Orthopedics
• Radiology
• Biomedical Engineering

Background:

• Medial meniscal extrusion (MME) is gaining attention in orthopedic research.
• Current evaluation methods for MME primarily rely on MRI, limiting accessibility.
• Limited studies have explored the utility of X-ray imaging for MME assessment.

Purpose of the Study:

• To evaluate the feasibility of measuring medial meniscal extrusion (MME) using X-ray.
• To develop and validate a novel index, the meniscal extrusion ratio, derived from X-ray measurements.
• To assess the correlation between X-ray-based MME measurements and MRI findings.

Main Methods:

• Medial meniscal extrusion (MME) and meniscal height were measured on X-ray images using gradation processing.
• The meniscal extrusion ratio was calculated by dividing extrusion length by meniscal height.
• Absolute medial meniscal extrusion was measured on MRI for comparative analysis.

Main Results:

• A strong correlation (r=0.860, p<0.0001) was found between the meniscal extrusion ratio derived from X-ray and MME measured by MRI.
• The cut-off value of 0.50 for the meniscal extrusion ratio on X-ray demonstrated high diagnostic performance (AUC=0.9825, sensitivity=0.9063, specificity=0.8663) for identifying MME on MRI.
• X-ray with gradation processing allows for reliable measurement of MME and calculation of the meniscal extrusion ratio without MRI.

Conclusions:

• The meniscal extrusion ratio calculated from X-ray is a reliable and strongly correlated indicator of medial meniscal extrusion (MME) compared to MRI.
• This X-ray-based method provides a non-invasive, accessible, and accurate approach for assessing MME.
• The developed meniscal extrusion ratio holds potential as a valuable tool in clinical practice for evaluating meniscal health.