A shoulder replacement does not repair a torn rotator cuff, but a specific type of replacement, called a reverse shoulder replacement, is designed to work without one. It bypasses the damaged tendons entirely by redesigning the joint so a different muscle powers your arm. This distinction matters because the type of replacement you need depends heavily on whether your rotator cuff is intact.
Why a Standard Replacement Needs an Intact Cuff
A traditional (anatomic) shoulder replacement recreates the natural ball-and-socket shape of your joint. It replaces worn-out cartilage and bone surfaces, but it still relies on your rotator cuff tendons to hold the ball centered in the socket and lift your arm. If those tendons are torn, the artificial joint has nothing stabilizing it. The humeral head (the ball) can migrate upward, and the replacement loosens or fails. For this reason, an anatomic replacement has historically been reserved for people with shoulder arthritis whose rotator cuff is still functional.
How a Reverse Replacement Works Around the Tear
A reverse shoulder replacement flips the anatomy. It places the ball on the shoulder blade and the socket on the upper arm bone. This seemingly simple swap changes the physics of the joint in a powerful way: it shifts the center of rotation downward and inward, giving the deltoid muscle (the large muscle capping your shoulder) a longer lever arm. With that extra mechanical advantage, the deltoid can lift and rotate your arm on its own, substituting for the missing rotator cuff.
The design also adds built-in stability. Because the socket wraps around the ball more tightly than in a natural shoulder, the joint stays in place even when the surrounding soft tissues are damaged or imbalanced. This semi-constrained design is what makes the reverse replacement viable for people whose rotator cuff is beyond repair.
When a Replacement Is the Right Choice
Not every torn rotator cuff leads to a shoulder replacement. Most tears, especially acute ones in younger patients, are treated with surgical repair, reattaching the torn tendons to the bone. A replacement enters the picture when the tear is irreparable and has already caused joint damage.
Surgeons classify a rotator cuff tear as irreparable based on several factors: the tear involves two or more tendons or measures larger than 5 cm, the muscle has been replaced by fatty tissue (meaning it can no longer contract effectively), or the patient has pseudoparalysis, where they physically cannot lift their arm despite trying. When an irreparable tear goes on long enough, the humeral head migrates upward and grinds against the bone above it. The joint surfaces erode, and the socket develops a scooped-out deformity. This combination of a destroyed cuff and a worn-out joint is called rotator cuff tear arthropathy, and a reverse replacement is the primary surgical solution.
The procedure tends to be recommended for older, lower-demand patients. Younger patients with irreparable tears but no arthritis may first try other options like tendon transfers or partial repairs before considering replacement.
Pain Relief and Functional Gains
The reverse replacement is particularly effective at reducing pain. Data from Johns Hopkins Medicine indicates that 85 to 90% of patients who undergo the procedure achieve excellent pain relief. The results are strongest for first-time replacements; patients who need a revision of a prior replacement tend to get less relief, likely due to accumulated scar tissue and long-term joint damage.
Functionally, most people regain the ability to lift their arm overhead and perform daily tasks like reaching a shelf, dressing, and washing their hair. The range of motion after a reverse replacement is typically less than what a healthy shoulder provides, and internal rotation (reaching behind your back) tends to recover the least. But for someone who could barely lift their arm before surgery, the improvement is significant.
What Recovery Looks Like
Recovery follows a structured timeline over roughly three to four months. For the first six weeks, you wear a sling at all times, including while sleeping, removing it only for guided exercises and physical therapy. During the first two weeks, movement is entirely passive: a therapist moves your arm for you to protect the healing tissues. From weeks two through six, you begin assisted exercises, using a pulley or cane to help raise your arm to about 90 degrees.
At six weeks, the sling comes off and you start actively moving your arm under your own power. This phase, from six to twelve weeks, focuses on building range of motion in all directions. After twelve weeks, therapy progresses toward strengthening and restoring as much movement as possible. Most people return to light daily activities by three months, though full recovery and strength gains can continue for six months or longer.
How Long the Implant Lasts
Data from the Norwegian Arthroplasty Register, tracking nearly 5,500 reverse shoulder replacements over up to 15 years, found a 10-year survival rate of 94%. That means roughly 19 out of 20 implants were still functioning a decade after surgery, which compares favorably with hip and knee replacements.
Over the long term, the overall complication rate is about 36%, though many of these are managed without major surgery. The most common complications include instability (the joint dislocating), which occurs in about 9% of cases, infection at a similar rate, and loosening of the socket-side component in about 6%. Stress fractures of the shoulder blade happen in roughly 4% of patients. About 23% of patients eventually need some form of revision surgery, most often for infection or instability.
Repair vs. Replacement: The Key Distinction
If your rotator cuff is torn but the tendons are still healthy enough to reattach and your joint surfaces are intact, a cuff repair is the better path. It preserves your natural anatomy and avoids the limitations and risks of an artificial joint. A shoulder replacement does not stitch torn tendons back together. It either works alongside an intact cuff (anatomic replacement) or works around a destroyed one (reverse replacement). The reverse design is a solution for the end stage of rotator cuff disease, when both the tendons and the joint have deteriorated past the point of direct repair.