Final answer:
After a total shoulder arthroplasty, the shoulder should be placed in abduction position to prevent scar tissue formation and improve mobility.
Step-by-step explanation:
After a total shoulder arthroplasty, the shoulder should be placed in a specific position called abduction. Abduction means that the arm is moved away from the body, in a sideways direction. This position helps to prevent the formation of scar tissue and increases shoulder mobility during the healing process.