The shoulder joint is comprised of three main bones: the collarbone (clavicle), the shoulder blade (scapula) and the upper arm bone (humerus). The glenoid (part of the scapula) and humeral head (part of the humerus) are normally the parts of the shoulder that have to be replaced because they rub together when you move your arm.
In a healthy shoulder, these portions of bone are covered with cartilage, which allows for painless motion—lifting, pushing and pulling. But arthritis can damage this protective cartilage, which makes these motions painful.
Arthritis is one of the most common conditions that causes wear and tear to your joint cartilage and develops after years of constant motion and pressure on the joints. If non-surgical treatment options such as medication, physical therapy or lifestyle changes fail to provide relief, your surgeon may recommend shoulder replacement surgery.
Shoulder replacement surgery replaces the damaged part of your shoulder to recreate the natural contours of the bones in a healthy shoulder.
During surgery, an incision is made in the front of the shoulder. Once the surgeon exposes the shoulder joint, the surgeon will remove the damaged bone and cartilage. The head of the humerus is then removed and a metal stem is placed into the humeral canal. This provides a stabilizing anchor for the new humeral head.
If the rotator cuff is no longer functioning normally, a surgeon may opt to perform a reverse total shoulder replacement. In this procedure, the anatomy of the shoulder is reversed by attaching a metal ball (glenosphere) to the glenoid and the plastic socket (humeral liner) to the upper humerus. A reverse shoulder replacement empowers the deltoid to become the main functioning muscle in the absence of a healthy rotator cuff.