Quantifying extensibility of rotator cuff muscle with tendon rupture using shear wave elastography: A cadaveric study

Area of Science:

• Orthopedic Surgery
• Biomechanical Engineering
• Medical Imaging

Background:

• Large rotator cuff tears present surgical challenges due to tear size, altered muscle mechanics, and limited musculotendinous extensibility.
• Poor extensibility can lead to incomplete reconstruction and repair failure from excessive post-operative stress.
• Accurate pre-surgical estimation of muscle extensibility is crucial for effective surgical planning and preventing intraoperative complications.

Purpose of the Study:

• To determine if quantified mechanical properties of the supraspinatus muscle measured by shear wave elastography (SWE) can predict musculotendinous unit extensibility.
• To assess the correlation between SWE modulus and supraspinatus muscle extensibility in cadaveric shoulders.

Main Methods:

• Utilized 45 fresh-frozen cadaveric shoulders (25 intact, 20 with rotator cuff tears).
• Measured passive stiffness in four anatomical regions of the supraspinatus muscle using SWE.
• Axially pulled the detached supraspinatus muscle under fixed scapula at 30N and 60N loads, correlating SWE modulus with experimental extensibility.

Main Results:

• A significant negative correlation was found between SWE measurements and experimental muscle extensibility.
• The SWE modulus in the anterior-deep region of the supraspinatus showed the strongest correlation with extensibility under both 30N (r=0.70, P<0.001) and 60N (r=0.68, P<0.001) loads.
• Quantitative SWE assessment demonstrated a high correlation with musculotendinous unit extensibility in cadaveric shoulders.

Conclusions:

• Quantitative SWE assessment of the supraspinatus muscle is highly correlated with the extensibility of the musculotendinous unit.
• This non-invasive technique shows potential for predicting muscle extensibility in rotator cuff tears.
• SWE can be a valuable tool for pre-surgical planning in rotator cuff repair, aiding in anticipating and managing intraoperative challenges.