The Coraco-Gleno-Scapular line: A simple tool for assessing glenoid bone defects

Area of Science:

• Orthopedic surgery
• Radiology
• Anatomy

Background:

• Shoulder instability often requires surgery, with glenoid bone loss being a critical factor.
• Current methods for identifying glenoid bone loss have limitations.
• The Coraco-Gleno-Scapular (CGS) line is introduced as a novel tool for assessing critical glenoid bone defects.

Purpose of the Study:

• To define the Coraco-Gleno-Scapular (CGS) line.
• To evaluate the CGS line's utility in guiding clinical decisions for shoulder instability based on glenoid bone loss.
• To propose that posterior CGS line defects indicate critical bone loss requiring surgery.

Main Methods:

• Analysis of 50 normal right shoulders (ages 18-40) using 3D en face glenoid views.
• Definition of the CGS line from the coracoid process to the anteroinferior pole of the scapula.
• Calculation of the anterior glenoid bone area relative to the CGS line using best-fit circle and glenoid index methods.

Main Results:

• The best-fit circle method showed a mean of 22.19% of glenoid surface area anterior to the CGS line.
• The glenoid index linear method indicated a mean of 27.2% of glenoid surface area anterior to the CGS line.
• 14 shoulders had <20% anterior glenoid area by the best-fit circle method; none were below 17.5%.

Conclusions:

• The Coraco-Gleno-Scapular (CGS) line is a reliable and simple method for assessing glenoid bone loss.
• The CGS line offers valuable guidance for managing shoulder instability.
• Its ease of use suggests potential for routine clinical application.