Reliable interpretation of scapular kinematics depends on coordinate system definition.

The method was built and tested in healthy cadaver scapulae and healthy living subjects, so it may not apply to people with shoulder instability, arthritis, or rotator cuff tear. The living-subject data came from a small research study, and the participants were younger than the cadaver population. The glenoid center coordinate system cannot be tracked with skin markers, so this method may not transfer directly to routine surface-marker motion capture. The study used biplane fluoroscopy and CT, which are not ordinary clinical tools, and the authors caution against applying the method to less accurate motion capture until error is quantified. Coordinate system conversion does not remove the separate problem that decomposition sequence also changes reported shoulder blade angles.

Publication types indicate NIH extramural and non-U.S. government research support. The authors declared no financial or personal relationships with other people or organizations related to the research.

Do not read this as a clinical test or treatment for shoulder patients. It is a research method for converting coordinate systems in healthy scapulae, and the authors caution against applying it to abnormal scapular morphology or less accurate skin-marker motion capture.