There are two common types of shoulder replacements:
Standard Total Shoulder Arthroplasty: Designed for patients with an intact rotator cuff.
Reverse Total Shoulder Arthroplasty: Designed for patients with severe and complete rotator cuff tears.
The shoulder joint is a ball-and-socket joint, much like the hip joint. The ball is the top of the arm bone (humerus), and the socket is within the shoulder blade (scapula). This joint allows people an enormous range of motion at the shoulder.
When shoulder replacement surgery is performed for severe arthritis, the ball is removed from the top of the humerus and replaced with a half-moon shaped metal implant. The implant is attached to a stem inserted down the center of the arm bone. The socket portion of the joint is shaved clean and replaced with a plastic socket that is cemented into the scapula.