I’ve been looking on-line for surgical options to a bum shoulder. I have a badly damaged rotator cuff and now arthritis that isn’t getting any better. I see the latest is a reverse shoulder replacement. That looks pretty cool. Would it work for me?

Reverse replacements put the ball of the joint just off the shoulder blade with the socket off the upper arm rather than the usual ball at the top of the bone and the socket on the shoulder blade. This design is especially helpful for patients who no longer have a stable shoulder.

The soft tissue envelope of muscles and tendons holding the shoulder joint in the socket is called the rotator cuff. The reverse shoulder replacement by its design is more stable and requires less soft tissue support to hold it in place. It seems ideal for people who have injuries of the rotator cuff resulting in degenerative changes in the joint progressing to arthritis.

The reverse shoulder joint isn’t a perfect solution. It comes with problems of its own. For example, some patients end up with pain, loss of motion, and a problem called impingement. Impingement results in an inability to put the arm all the way down at the side. The implant design, location, and angle result in the two parts of the implant bumping up against each other, preventing full motion.

Specifically, the medial (inside) edge of the socket (now located at the top of the humerus) bumps up against the lateral outside edge of the scapula (shoulder blade) where the new round ball (glenosphere) is located. This creates a problem called scapular notching. Depending on the location of the glenosphere, motion can range from zero degrees (no impingement) up to 38 degrees of impingement (in other words, the arm is 38 degrees away from the body).

When reverse shoulder replacements were first introduced, the glenosphere was placed in the middle of the glenoid (anatomic shoulder socket). But these problems developed and surgeons recognized the benefit of changing their surgical technique to avoid complications. Despite changes made, scapular notching is still a problem.

The best person to answer your question is the surgeon. After completing a patient interview with history and clinical exam, the surgeon will be able to advise you as to the best treatment plan for your particular situation. If surgery is indicated, the type of procedure, pros and cons, and advantages and disadvantages will be discussed. Don’t hesitate to ask about a reverse shoulder replacement during your visit. That will be the best way to see if it’s for you.