 Third, most partial-thickness cuff tears do not occur on bursal surface fibers, where mechanical abrasion from the acromion does occur.Fourth, it has been suggested that bursal surface cuff tears could be responsible for subacromial spurs and not the opposite.And finally, there is growing evidence that routine acromioplasty may not be required for successful rotator cuff repair, which would be an unexpected finding if acromial shape had a major role in generating tendon lesions.