In my professional opinion, reverse shoulder replacement represents
one of the greatest innovations in orthopedic surgery. Originally
developed in Europe in the 1990s, reverse shoulders have been used in
the United States for almost twenty years. Originally used for
patients with non-repairable rotator cuff tears and shoulder
arthritis, the indications have broadened significantly over time.
Some of the indications for a reverse shoulder include shoulder
arthritis with a non-repairable rotator cuff tear, a massive rotator
cuff tear without arthritis, select shoulder fractures, shoulder
arthritis associated with a large amount of glenoid (socket) bone
loss, instability of the joint surface, and revision cases.
In a reverse shoulder, a small metal baseplate is attached to the
glenoid (socket) with medical screws. This metal baseplate is coated
with a special material that allows bone to grow into the implant
which is how it stays attached in the long-term. Compared to an
anatomic shoulder replacement where cement is routinely used to attach
the glenoid (socket) implant, in a reverse replacement cement is not
used on this socket implant. After the metal baseplate is in place, a
round sphere, called a glenosphere, is inserted onto it. This makes
the socket side, which used to be “cup” shaped, now round.
The below two images are edited to illustrate the
differences between the anatomic and reverse shoulder implants. In
reality, the implants shouldn’t have a gap between them. The left
image shows the anatomic shoulder implanted; on the right shows the
reverse shoulder implanted.