Proximal humeral coordinate systems can predict humerothoracic and glenohumeral kinematics of a full bone system.
Hema J Sulkar, Jared L Zitnay, Klevis Aliaj and 1 others
PMID 34564010WHAT IT FOUND
Shoulder motion measured from proximal-only scans can be translated into whole-bone shoulder coordinates with small errors for arm elevation and the plane of arm elevation.
Axial rotation was less reliable.
Key findings
01Shoulder elevation and plane of arm elevation could be converted from proximal-only coordinate systems to the standard whole-bone system with mean errors no greater than 1.6°.
02Axial rotation was predicted less accurately, with mean errors up to 7°, although this was better than the 11-21° errors seen without conversion.
03The three proximal coordinate-system conversions performed similarly, with no significant differences in error between them.
STILL TO COME
How it was doneWhat they found
Read the rest of this summary
You get three full summaries a month, free, and we do not ask for a card. Search, the TL;DRs and your library stay unlimited either way.
What it does not show
The matrices were built from healthy cadaver humeri, so severe shoulder pathology may make landmark selection less reliable. Axial rotation error was higher than the study's 5° target because humeral twist cannot be predicted from proximal anatomy alone. The motion data came from biplane fluoroscopy, not ordinary skin-marker motion capture, so the error in common clinic tracking methods is unknown. The paper reports coordinate-system conversion errors, not symptoms, function, or treatment response.
Declared interests
The supplied text does not include a conflict-of-interest declaration. The article is marked as NIH extramural research support.
The easy way to misread this
Do not conclude that this method validates everyday clinical shoulder motion tracking. It was tested with research bone-tracking imaging, not ordinary skin-marker motion capture, and axial rotation remained less accurate.