Surgically repaired rotator cuff tears fail at surprisingly high rates, approaching 20-94% as determined by MRI 3, 9, 13, 20, 28, 40, 52, 58. Non-modifiable variables associated with rotator cuff repair failure include: duration of symptoms 9, 19, 39, fatty infiltration of the atrophied muscle 6, 15, 17, larger rotator cuff tears 6, 9, 19, 20, 21, 26, 39, 47, older age 9, 20, 22, 48, 55, co-morbidities 48, and workers compensation claims 2, 22, 23. Potentially modifiable variables include: tobacco use 11, 38, limited preoperative range of motion 45, and surgeon volume 48.