The Impact of Decreased Scapulothoracic Upward Rotation on Subacromial Proximities.

The study was cross-sectional and grouped people by movement rather than symptoms, so it cannot show that decreased upward rotation causes pain or rotator cuff pathology. The low and high upward rotation groups had similar proportions of symptomatic and asymptomatic participants, so the kinematic groups did not line up with symptoms. The low upward rotation group had greater mass and body mass index than the high group, and symptomatic participants in the low group had higher maximum pain, so these differences may contribute to the findings. The mid upward rotation group was not analyzed. Mean participant age was 32 years, so the findings may not apply to older adults. Single-plane fluoroscopy can create out-of-plane errors that may affect subacromial distance measurements. The coracoacromial ligament was modeled as a plane, and rotator cuff thickness was measured at one articular-margin slice. Group classification used upward rotation at 30° of humerothoracic elevation, but there is no validated clinical classification for decreased upward rotation. The study investigated only subacromial compression, not other mechanisms of rotator cuff injury or shoulder pain.

Do not conclude that decreased scapulothoracic upward rotation causes shoulder pain or rotator cuff pathology. This was a cross-sectional imaging study that grouped people by motion, did not track outcomes, and found no difference in contact prevalence or proximity area between groups. The suggestion to increase upward rotation is an expert recommendation, not a tested intervention.