Increased Glenoid Retroversion Is Associated With Increased Rotator Cuff Strength in the Shoulder.
Contributing USMA Research Unit(s)
Faculty Learning Innovation Collaboration and Research
The American journal of sports medicine
BACKGROUND: The rotator cuff muscles are critical secondary stabilizers in the shoulder. Increased glenoid retroversion and rotator cuff strength have been associated with the risk of posterior shoulder instability; however, the effect of increased glenoid retroversion on rotator cuff strength remains unclear.
PURPOSE/HYPOTHESIS: The purpose was to examine the association between glenoid version and rotator cuff strength in the shoulder in a young and healthy population with no history of shoulder instability. The hypothesis was that increased glenoid retroversion would be associated with increases in rotator cuff muscle strength.
STUDY DESIGN: Cross-sectional study; Level of evidence, 3.
METHODS: A prospective cohort study was conducted over a 4-year period within a high-risk population to identify the risk factors for shoulder instability. Analyzed participants included 574 freshmen entering a United States service academy. Baseline data collected upon entry into the study included magnetic resonance imaging measurements of glenoid version. Rotator cuff strength was also assessed at baseline using a handheld dynamometer. Internal and external rotation strength were assessed with the glenohumeral joint positioned in neutral and in 45° of abduction. The current study represents an analysis of the baseline data from this cohort.
RESULTS: The mean age, height, and weight of participants was 18.77 ± 0.97 years, 176.81 ± 8.48 cm, and 73.80 ± 12.45 kg, respectively. The mean glenoid version at baseline was 7.79°± 4.85° of retroversion. Univariate linear regression analyses demonstrated that increased glenoid retroversion was associated with increased internal and external rotation strength of the rotator cuff in neutral and 45° of abduction (
CONCLUSION: The results of this study demonstrate that as glenoid retroversion increases, internal and external rotation strength of the rotator cuff also increase in a young and healthy athletic population. These compensatory changes may contribute to increased glenohumeral dynamic stability in the presence of worse static stability with increasing retroversion.
Cameron, Kenneth L; Tennent, David J; Sturdivant, Rodney X; Posner, Matthew A; Peck, Karen Y; Campbell, Scot E; Westrick, Richard B; and Owens, Brett D, "Increased Glenoid Retroversion Is Associated With Increased Rotator Cuff Strength in the Shoulder." (2019). West Point Research Papers. 596.
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