Characterization of glenoid bone remodeling in professional baseball pitchers

  • Jonathan Rassi
  • Naveen Subhas
  • Jennifer Bullen
  • Michael Forney
  • Joshua PolsterEmail author
Scientific Article



To characterize the appearance, location, severity, and prevalence of focal glenoid retroversion on shoulder MRI in professional baseball pitchers versus age-matched controls.

Materials and methods

In this retrospective review, two musculoskeletal radiologists evaluated shoulder MRI examinations from 40 professional baseball pitchers and 40 age-matched controls. Images were scored for the presence of a focal posterior glenoid convexity and the clock face positions involved. A consensus interpretation was also performed. A third reader identified the presence of additional shoulder abnormalities.


After consensus, 60% (24/40) of pitchers were found to have focal glenoid retroversion versus 20% (8/40) of controls (p = 0.001). The most apparent location was posterior or posterior-superior, from 7.75 o’clock to 10.5 o’clock (median, 9.75 o’clock; interquartile range, 9.25–10 o’clock). The median clock angle of involvement was greater in pitchers than in controls (30° vs. 0°; p < 0.001). Interreader agreement regarding the presence or absence of focal glenoid retroversion was moderate (Cohen’s kappa, 0.49). Focal glenoid retroversion was more prevalent among subjects with additional shoulder abnormalities (p = 0.014).


Glenoid remodeling occurs in the throwing shoulder of professional baseball pitchers and manifests as focally convex morphology of the posterior or posterior-superior glenoid. This type of remodeling does not appear to be associated with a lower prevalence of injuries related to posterior-superior impingement.


Glenoid Retroversion Shoulder Baseball Pitcher Enchondral ossification 



The authors would like to thank Dr. Anwar Ashraf for assistance with initial study design, Ms. Megan Griffiths for review of the manuscript, and Mr. Joseph Kanasz, Ms. Kathleen Miller, and Ms. Bernastine Buchanan for assistance with the figures.

Compliance with ethical standards

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.

Conflict of interest

The authors declare that they have no conflict of interest.


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Copyright information

© ISS 2019

Authors and Affiliations

  • Jonathan Rassi
    • 1
  • Naveen Subhas
    • 1
  • Jennifer Bullen
    • 2
  • Michael Forney
    • 1
  • Joshua Polster
    • 1
    Email author
  1. 1.Imaging InstituteCleveland ClinicClevelandUSA
  2. 2.Quantitative Health SciencesCleveland ClinicClevelandUSA

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