Anatomic Shoulder Arthroplasty

Who is a candidate?
Anatomic shoulder arthroplasty (sometimes called an “anatomic shoulder replacement”) is usually recommended for people with severe shoulder arthritis, in which the smooth cartilage that cushions the joint has worn away. Candidates often have pain that limits their daily activities, stiffness that makes lifting the arm difficult, and damage seen on X-rays. For this surgery to work well, the rotator cuff tendons (the group of muscles and tendons that help move and stabilize the shoulder) need to be healthy and intact.

What does the surgery involve?
In this procedure, the worn-out parts of the shoulder joint are replaced with artificial components that mimic the shoulder’s natural anatomy. The ball of the humerus (upper arm bone) is replaced with a metal ball attached to a stem, and the socket (glenoid) is resurfaced with a smooth plastic piece. Together, these components allow the shoulder to glide more smoothly, reduce pain, and restore motion.

How is it different from reverse shoulder replacement?
In anatomic replacement, the surgeon rebuilds the joint in its normal orientation—ball on the arm side, socket on the shoulder blade side. This type of replacement relies on the rotator cuff to function well.
A reverse shoulder replacement, in contrast, switches the ball and socket positions: the ball is placed on the shoulder blade and the socket is placed on the arm. This design gives the deltoid muscle more power to lift the arm when the rotator cuff is torn or not working.

What are some of the long-term downsides?
While anatomic replacements can provide excellent pain relief and improved function, they are not perfect. Over time, the plastic socket (polyethylene component) can loosen or wear out, especially in younger, more active patients. If this occurs, a revision surgery may be needed. As with all joint replacements, there are also risks of stiffness, instability, or infection, though these are less common.

What is recovery like?
Recovery is a gradual process. The arm is usually supported in a sling for the first few weeks to protect the joint as it heals. Physical therapy begins soon after surgery to restore range of motion, followed by strengthening exercises. Most people can resume basic activities within a few weeks, but full recovery—including return to sports or heavy lifting—often takes 4–6 months. The goal is long-lasting pain relief and improved use of the shoulder in daily life.