The Law of Use and Disuse: Critical Shoulder Angle and Rotator Cuff Tears-Association Does Not Imply Causation.

The critical shoulder angle has been associated with the development of rotator cuff lesions. Over time, this association has been interpreted as a cause-effect relation without scientific evidence. Beyond the controversies that exist on the reliability and relevance of this radiographic parameter, the critical shoulder angle per se may not be responsible for rotator cuff tears because patient activities throughout several decades could induce not only cuff lesions but also bone remodeling at the acromial level.