A reverse shoulder replacement is a type of joint replacement surgery that flips the normal anatomy of the shoulder. Instead of placing a ball on the upper arm bone and a socket on the shoulder blade (as in a conventional shoulder replacement), the surgeon attaches a metal ball to the shoulder blade and a plastic socket to the upper arm. This swap allows the large deltoid muscle to power arm movement, bypassing the rotator cuff entirely. It’s the go-to surgery when the rotator cuff is too damaged to support a standard replacement.
How It Differs From a Standard Replacement
In a healthy shoulder, four small rotator cuff muscles hold the ball of the upper arm bone centered in the socket while the larger deltoid muscle lifts the arm. A conventional shoulder replacement recreates this same arrangement with artificial parts, so it still depends on a working rotator cuff to function properly.
A reverse replacement changes the physics of the joint. By placing the ball on the shoulder blade side and the socket on the arm side, the center of rotation shifts inward, closer to the body. This increases the mechanical leverage of the deltoid muscle, giving it a longer “lever arm” to lift and rotate the arm. The posterior part of the deltoid, which normally pulls the arm downward, actually switches roles and helps with lifting in a reverse replacement. The result is a shoulder that can raise and move without any contribution from the rotator cuff at all.
Who Needs a Reverse Replacement
The most common reason is a condition called cuff tear arthropathy, where a massive, irreparable rotator cuff tear has been present long enough that the shoulder joint has developed severe arthritis. Without a functioning rotator cuff, the ball of the upper arm migrates upward and grinds against the bone above it, causing pain and progressive joint destruction. A conventional replacement would fail in this situation because there’s no rotator cuff to stabilize it.
Reverse replacements are also used for complex fractures of the upper arm bone near the shoulder, particularly in older patients where the bone fragments are too damaged to reconstruct reliably. Other candidates include people whose previous conventional shoulder replacement has failed and those with severe shoulder arthritis combined with significant rotator cuff weakness.
What the Implant Looks Like
The implant has two main sides. On the shoulder blade, a flat metal baseplate is secured directly into the bone of the socket (the glenoid) with screws. A smooth metal half-sphere called a glenosphere attaches to the baseplate, creating the new “ball” of the joint. On the arm side, a metal stem fits down into the hollow canal of the upper arm bone. A plastic cup sits on top of the stem, forming the new “socket” that glides over the glenosphere. Surgeons choose from a range of sizes and angles to match each patient’s anatomy.
What Happens During Surgery
The procedure typically takes one to two hours under general anesthesia, often combined with a nerve block to manage pain afterward. The surgeon makes an incision at the front or side of the shoulder and works between muscles to reach the joint.
On the shoulder blade side, the damaged socket surface is smoothed with a reamer to create a flat, even surface for the baseplate. A central hole is drilled, the baseplate is tapped into place, and screws lock it to the bone. The glenosphere is then pressed onto the baseplate. On the arm side, the surgeon removes the damaged ball of the upper arm bone and hollows out the bone canal with progressively larger reamers. A trial implant is placed first to check fit, stability, and tension. Once everything looks right, the final stem is cemented into position and the plastic socket is secured on top. The joint is then reduced (put back together) and the incision is closed.
Recovery Timeline
You’ll wear a sling full time for the first six weeks, including while sleeping. Recovery moves through distinct phases.
During the first two weeks, the focus is on protecting the repair while gently preventing stiffness. A physical therapist will guide you through passive range of motion exercises, where your arm is moved for you rather than by your own muscles. Early goals include reaching about 130 degrees of forward arm elevation and 25 degrees of outward rotation, all performed while lying on your back.
Between weeks two and six, you begin active-assisted exercises. This means you start using your own muscles with help from a pulley system or a cane to guide the movement. Forward arm elevation is initially limited to about 90 degrees (shoulder height) during this phase. The sling stays on whenever you’re not doing exercises.
At six weeks, the sling comes off. From weeks six through twelve, the goal shifts to gradually building strength and increasing range of motion. Most people notice significant improvement in pain and function by three months, though full recovery continues for several months beyond that.
What You Can and Can’t Do Afterward
Most people who have a reverse shoulder replacement can lift their arm above shoulder height, but not always fully overhead. A realistic expectation is being able to reach to about neck level or slightly higher. Activities like reaching a shelf at eye level, washing your hair, and getting dressed become manageable again. Lifting your arm straight up to cover your ear with your upper arm may not be possible.
Your surgeon will likely set a permanent or semi-permanent limit on how much weight you can lift with that arm. Intense physical activities, heavy lifting, and contact sports are generally off the table long-term to protect the prosthesis and the deltoid muscle that now does all the work. Low-impact activities like swimming, golf, and light gardening are typically fine once you’ve fully healed.
How Long the Implant Lasts
Modern reverse shoulder implants have strong longevity. A systematic review published in The Lancet Rheumatology found that the 10-year implant survival rate was about 94% for patients with osteoarthritis and about 94% for patients with cuff tear arthropathy. These numbers mean that roughly 19 out of 20 implants are still functioning well a decade after surgery. Younger, more active patients may face higher revision rates over time simply because they put more cumulative stress on the prosthesis.
Possible Complications
The most talked-about complication specific to reverse replacements is scapular notching, where the plastic socket component repeatedly contacts the edge of the shoulder blade during movement, gradually wearing a groove into the bone. In one mid-term study, notching appeared in about 27% of patients, though the majority of cases were mild (grades 1 and 2 on a four-point scale) and didn’t cause symptoms or require further surgery. Newer implant designs have reduced notching rates by adjusting the position and angle of the components.
Dislocation is another risk, though less common than with conventional replacements because the deeper socket design provides inherent stability. Infection occurs in a small percentage of cases and sometimes requires a staged revision, where the implant is removed, the infection is treated, and a new implant is placed weeks or months later. Other possible complications include nerve injury, fractures around the implant, and loosening of the baseplate over time.
Outcomes for Most Patients
For people with a destroyed rotator cuff who’ve been living with significant shoulder pain and an inability to raise their arm, a reverse replacement is often transformative. Pain relief is the most consistent benefit. Functional improvement varies, but most patients regain enough motion to handle daily tasks that had become impossible. The combination of reliable pain reduction, a 10-year survival rate above 90%, and expanding implant design options has made reverse shoulder replacement one of the fastest-growing orthopedic procedures worldwide.