Reverse Shoulder Replacement Surgery
A reverse shoulder replacement is a design in which the positions of the ball and socket are switched: A metal ball implant is placed where the patient’s own natural socket was, and a plastic socket implant is placed on the head of the humeral head.
The design reasoning for the reverse shoulder replacement is as follows: In a healthy person, the shoulder ball rests against the socket (rather than being firmly embedded within the socket, as in a hip joint. Because of this location, the ball depends on the tendons that surround the socket to both hold it in place and push it.
But for other forms of arthritis these tendons are badly weakened, broken or unable to function. The ball implant used in a conventional shoulder replacement will in such situations have no soft tissue to keep it in place and/or push it.