The Shoulder Joint

The shoulder joint is a connection between two bones, which form the ball and the socket. The shoulder is the most flexible of all the joints in the body. The rounded head or ball of the upper arm bone (humerus) and the cup like formation of the shoulder blade (scapula) meet to form the shoulder.

The rotator cuff is a group of muscles and tendons in the shoulder, connecting the upper arm to the shoulder blade. The rotator cuff helps to lift the arm over the head and also helps to hold the ball (humeral head) in the socket (glenoid) of the shoulder.

A healthy shoulder has smooth cartilage covering where the bones of the upper arm and the shoulder meet. Cartilage can wear over time from arthritis or injury. This causes the ends of the bones to rub against each other and leads to pain, stiffness, limited movement, and a decreased ability to perform activities of daily living.

Why Choose Shoulder Replacement?

The main reason to have a shoulder replacement is to relieve pain. If you need a shoulder replacement, Dr. Burns will choose one of the following procedures to repair your shoulder arthritis: anatomic total shoulder replacement, reverse shoulder replacement, or hemiarthroplasty (partial replacement, recommended in certain circumstances).

Anatomic Total Shoulder Replacement

Anatomic total shoulder replacement is a surgical procedure that removes the damaged ball and socket and provides a new metal and plastic ball and socket. This replaces the arthritic or “worn out” cartilage. This procedure works best for patients who have a normal and intact rotator cuff, and who have not excessively ground down the remaining bone. Dr. Burns will make an incision on the front of your shoulder and remove the cartilage and bone that has been damaged by arthritis or injury. The upper arm bone (humerus) is resurfaced with a metal stem and ball made of titanium and cobalt chrome. The socket (glenoid) is resurfaced with a plastic liner. Often, this plastic liner will have a metal pin or tray to support it.

Reverse Total Shoulder Replacement

Reverse total shoulder replacement is a surgical procedure for patients who have arthritis and/or damage to their rotator cuff that cannot be repaired. Reverse shoulder replacement also works well for people who have significant bone loss around their shoulder, that can occur from years of bone-on-bone grinding of the ball and socket. Reverse shoulder replacement also can be used to treat severe shoulder fractures. This procedure is called a “reverse” because the position of the ball and the socket are switched in this type of replacement. The socket (glenoid) is resurfaced with a metal base and a ball made of cobalt chrome. The upper arm bone (humerus) is resurfaced with a metal stem and plastic cup liner. To watch a video of reverse shoulder replacement, click here.

Partial Shoulder Replacement (Hemiarthroplasty)

Occasionally, Dr. Burns may select an option called hemiarthroplasty, which is a replacement of the ball at the upper end of the arm bone (humerus) only. The socket is not replaced in this procedure with a metal and plastic part, although Dr. Burns will often rebuild or cushion the area with cadaver donated tissue, called allograft.