There are both cemented and noncemented shoulder prostheses.
A noncemented prosthesis is tapped into the humerus bone place during the surgery, and it is initially held steady by forces called hoop stresses–like a cork being pressed into the top of a bottle. Noncemented prostheses have a roughened surface, and eventually the surrounding bone will grow into the rough metal surface to provide additional stability.
Sometimes the humeral component is cemented into place. This technique is more common for revision surgery.
The polyethylene glenoid component (the socket) is almost always cemented into place at the time of surgery.