Increased Glenoid Retroversion Is Associated With Increased Rotator Cuff Strength in the Shoulder

Area of Science:

• Orthopedics
• Sports Medicine
• Biomechanics

Background:

• Rotator cuff muscles are key secondary stabilizers of the shoulder.
• Increased glenoid retroversion and rotator cuff strength are linked to posterior shoulder instability risk.
• The relationship between increased glenoid retroversion and rotator cuff strength is not well understood.

Purpose of the Study:

• To investigate the association between glenoid version and rotator cuff strength in young, healthy individuals without shoulder instability.
• To test the hypothesis that increased glenoid retroversion correlates with enhanced rotator cuff muscle strength.

Main Methods:

• Cross-sectional study (Level of evidence, 3) analyzing baseline data from a prospective cohort.
• 574 healthy freshmen underwent magnetic resonance imaging for glenoid version measurement.
• Rotator cuff strength (internal and external rotation) was assessed using a handheld dynamometer in neutral and abducted positions.

Main Results:

• Mean glenoid version was 7.79° ± 4.85° of retroversion.
• Increased glenoid retroversion showed a significant association with increased internal and external rotation strength (P < .001).
• These associations remained significant in multivariable models controlling for confounders.

Conclusions:

• In young, healthy athletes, greater glenoid retroversion is associated with increased rotator cuff strength.
• These findings suggest compensatory muscular adaptations may improve dynamic glenohumeral stability in the presence of increased retroversion.