Influence of radiographic viewing perspective on the Reverse Shoulder Arthroplasty (RSA) angle

This data quantifies the Reverse Shoulder Arthroplasty (RSA) Angle on digitally reconstructed radiographs (DRRs) that were generated from computed tomography (CT) scans of cadaveric scapulae. The RSA Angle was first described by Boileau in 2019 (https://pubmed.ncbi.nlm.nih.gov/30935825/). To measure the RSA Angle, the floor of the supraspinatus fossa provides the horizontal reference axis, R is the point of intersection of this line and the glenoid, S is the most inferior point on the glenoid rim, and A is the point creating a line perpendicular to the floor of the fossa passing through S. The angle between points R, S and A is the RSA angle. When viewed as a true anterior-posterior (AP) radiograph only one RSA angle is calculated since the glenoid is viewed in profile, but when the viewing perspective is altered the glenoid face is visible to varying degrees. Thus, the RSA angle could be calculated at multiple locations of intersection, notably the medial rim of the glenoid (red), lateral rim of the glenoid (green), or glenoid midline (blue). This study quantified the effect of viewing perspective on perceived measures of the RSA Angle in 2D, as well as on 3D models of the respective scapulae to determine the relationship between 2D and 3D RSA angles. Note that most of the 3D models used in the present analysis can be found in a prior data release on Zenodo.org (https://doi.org/10.5281/zenodo.14590062). A key linking the present specimen IDs to those in the prior release can be found in Appendix1_RSA_angles_EXPANDED.xlsx, Sheet ‘2D vs. 3D’, column M. Those models missing from the prior release (i.e., listed as ‘NA’ in Appendix1) are provided here using the naming convention consistent with the present release.