Good evening @changu0, Thanks for taking care of your Mom. I can imagine that you would like to help relieve her of pain and discomfort. Were you with her when she was released from the surgical center? Did you receive any information or have a conversation with any of the medical staff about how best to handle this situation? It might have been entitled, "What to do when I have pain.?"

And one more question, did your Mom have physical therapy either in-home or in a treatment facility? That might also be helpful. Somehow it seems like there might be some inflammation or something causing the pain. Does she elevate the knee during the day? When your Mom goes to bed, do you place a pillow under her knees? I still do that whenever my TKR knee gets cranky. And they can do that occasionally.

Do you use ice packs? Can you feel any swelling? What else have you noticed or your Mom has mentioned that could be helpful?
May you be safe and protected.
and
May your Mom be safe and protected.
Chris