Shoulder subacromial decompression (also called acromioplasty) is a surgical procedure to treat shoulder impingement, a common condition that causes weakness in your shoulder and pain when you raise your arm above your head. It is performed using keyhole surgery.
Shoulder impingement occurs when the tendons that support the rotator cuff muscles become dysfunctional and damaged.
Sometimes the shape of the bones at the top of your shoulder blade (the acromion) genetically predisposes you to irritation of the tendons. Bony spurs on the acromion can also cause damage to the tendons.