During a shoulder manipulation under anesthesia, can it dislocate? (had prior surgery for severe arthritis, trying to avoid replacement) thank you

Possible: But unusual. Trying to rotate and break up adhesions i suspect. Enhance mobility and range of motion for you.

Rare: Manipulation is done for frozen shoulder, not for arthritis. Will not help arthritis. Would be extremely unlikely to dislocate, and by the same token extremely unlikely to help you regain and maintain rom.

Theoretically yes.: Once a patient is under general anesthesia they cannot tell a surgeon when the shoulder is reaching its tolerance. The surgeon should be able to tell by tension and knowledge of the surgery beforehand, but it is theorectically possible that they might discloate the shoulder during the procedure. The chance of this is very small, and the surgeon will try to relocate the shoulder before you wake.