Comparison of two- and three-dimensional implant-based scapulohumeral rhythm measurements derived from two radiographic images in shoulders with reverse total shoulder arthroplasty

This study demonstrated a significantly strong positive correlation between 2 measures of SHR. However, both fixed bias and proportional bias were observed. Consequently, while a 2D measurement of SHR may offer some clinical utility, it is crucial to recognize its tendency to underestimate the mean SHR compared to 3D measurement.