What is the definition or description of: total shoulder joint replacement?

Ball and Socket : More information is here: http://www.Theshouldercenter.Com/shoulder-replacement.Htm there are different types of total shoulder replacements where both the ball and socket are replaced or resurfaced. A standard total shoulder replacement and the newer reversed total shoulder replacement seen in the image.

Shoulder Replacement: In shoulder replacement surgery, the damaged parts of the shoulder are removed and replaced with artificial components, called a prosthesis. The treatment options are either replacement of just the head of the humerus bone (ball), or replacement of both the ball and the socket (glenoid).

Total Shoulder : In a total shoulder arthroplasty, the arthritic parts of the shoulder are replaced. A metal ball is used to replace the humeral head and the glenoid (socket) is resurfaced with a piece of plastic.