In this procedure, both the ball (humeral head) and the socket (glenoid) of the shoulder joint are replaced with prosthetic components. It is most commonly performed in cases of osteoarthritis or rheumatoid arthritis where the joint cartilage has worn away.

Only the humeral head (ball) is replaced with a prosthesis, while the glenoid (socket) is left intact. This is usually done when the glenoid is in relatively good condition, but the humeral head is damaged due to arthritis or trauma.

This procedure is used when the rotator cuff muscles, which are responsible for shoulder movement, are severely damaged or torn beyond repair. The positions of the ball and socket are reversed, with the ball placed on the shoulder blade and the socket on the arm bone. This allows the deltoid muscle to compensate for the damaged rotator cuff, restoring shoulder function.