An acromioplasty is when bone on the acromion, which is above the rotator cuff
, is shaved down.
This is typically done if there is a large bone spur coming off the acromion. The rotator cuff attaches to the humerus, and the muscles of the rotator cuff pull on the cuff to elevate the shoulder. If the cuff is torn, it is repaired back to the humerus.