Shoulder joint angles in supine and upright imaging of the pre-operative reverse total shoulder arthroplasty patient

This code analyzes scapulothoracic and glenohumeral joint angles from subjects pre-operative to reverse total shoulder arthroplasty (rTSA) using anatomic landmark data from supine CT scans and upright seated biplane fluoroscopy/optical motion capture. Anatomical coordinate systems for the torso, scapula, and humerus are defined based on landmark positions, guided by ISB recommendations (https://pubmed.ncbi.nlm.nih.gov/15844264/) but with variances to generate consistent analyses unaffected by posture and limitations of clinical medical imaging. Notably, the sternum is used as the definitive thorax Y-axis as it should be self-consistent between both supine and upright data collections. The data is formatted in the same manner as prior releases of data from: - healthy shoulders (https://doi.org/10.5281/zenodo.14889478) - shoulders after rTSA (https://doi.org/10.5281/zenodo.16537557)