What's the difference between shoulder replacement and resurfacing?

Shoulder replacement is the removal of the shoulder socket and head of the humerus (upper arm bone). These parts are replaced with an artificial implant.

On the shoulder socket side, a cup-shaped metal or ceraminc implant is pressed or cemented into the bone. On the humeral side, an implant shaped like the head of a humerus with a long stem is inserted down into the shaft of the humerus. New bone from the humerus grows into and around the implants.

With joint resurfacing, the surgeon removes any bone spurs and smooths the joint surface. Then the joint surface is covered with tissue from some other part of the body. This could be a piece of tendon, flap of muscle, or rim of meniscus. The tissue usually comes from a donor bank.

Biologic resurfacing is also known as interpositional arthroplasty. It has been around in one form or another since the mid-1800s. It is one alternative to a total joint replacement for young, active adults. Less bone is removed. This makes it possible to convert to a total shoulder replacement later, if needed.