Sonographic evaluation of lateral meniscal extrusion: implementation and validation

Area of Science:

• Orthopedics
• Radiology
• Musculoskeletal Imaging

Background:

• Lateral meniscal extrusion (ME) is a key indicator and prognostic factor for knee pathologies.
• A standardized ultrasound protocol for lateral ME assessment is currently lacking.
• This study addresses the need for a reliable ultrasound examination protocol for lateral ME.

Purpose of the Study:

• To develop and validate a standardized ultrasound-based examination protocol for measuring lateral meniscal extrusion (ME).
• To assess the reliability and validity of ultrasound measurements of lateral ME.

Main Methods:

• Healthy volunteers (n=11) and patients post-lateral meniscal repair (n=10) were included.
• Lateral ME was measured using ultrasound (US) and MRI (patients only) under unloaded and loaded (50% body weight) conditions.
• Interrater and intrarater reliability (US) and validity (US vs. MRI) were assessed.

Main Results:

• Ultrasound demonstrated excellent intrarater (ICC=0.942) and good interrater (ICC=0.904) reliability for lateral ME measurements.
• Agreement between ultrasound and MRI measurements was poor (ICC=0.439).
• Ultrasound systematically overestimated lateral ME by an average of 1.1 mm compared to MRI.

Conclusions:

• Ultrasound is a reliable, rapid, and cost-effective tool for measuring lateral meniscal extrusion.
• The current ultrasound protocol provides reliable measurements but results are not directly interchangeable with MRI data.