Editorial Commentary: Is Your Critical Shoulder Angle Accurate? Only If You Can Verify That You Have the Correct Images.

The critical shoulder angle (CSA) has been the focus of significant research related to the etiology and prognosis of rotator cuff tears in recent years, but the accuracy of CSA measurements on plain anteroposterior (Grashey) radiographs has been questioned. Research to better understand what qualifies as a "tolerable" radiograph for reliable measurement of the CSA can inform best practices for obtaining plain radiographs. Optimal measurements rely on optimal images, and knowing how much room for error there is regarding malrotation provides surgeons with unbiased criteria to rule out inadequate images.