A reverse total shoulder replacement is designed for individuals with large rotator cuff tears with cuff tear arthropathy — a complex type of shoulder arthritis. This type of shoulder replacement is designed to use different muscles to move the arm. For these patients, conventional total shoulder replacement may result in pain and limited motion, and so reverse total shoulder replacement is a far better option.
Normally in a shoulder, the rotator cuff muscles help position and power the arm during range of motion. A conventional replacement device also uses the rotator cuff muscles to function properly. When someone has a large tear in their rotator cuff and/or cuff tear arthropathy, these muscles can no longer be put to use. The reverse total shoulder replacement relies on the deltoid muscle, instead of the rotator cuff, to power and position the arm.
Every year, thousands of conventional total shoulder replacements are successfully done in the U.S. for patients suffering from arthritis in the shoulder. A conventional shoulder replacement device mimics the normal anatomy of the shoulder: a plastic “cup” is fitted into the shoulder socket (glenoid), and a metal “ball” is attached to the top of the upper arm bone (humerus). In a reverse total shoulder replacement, the socket and metal ball are switched. The metal ball is fixed to the socket and the plastic cup is fixed to the upper end of the humerus.