I had this wonderful device for my first knee replacement last summer. I was able to press a little button that delivered pain killing medicine directly into my knee. You have it with you in a little fanny pack. On the day I checked out of the hospital, I told my surgeon I really hated to see that device go, and he gave me the good news that I could keep it if I wanted. Before I left for home, they filled the thing up with medicine, and that lasted two more days at home. The very minor down side is that I was anxious to have a shower, and the only reason I couldn't is that you can't get that thing wet. The anesthesiologist put this in before surgery, and surprisingly it didn't hurt a bit. Once it was empty at home, I was worried about two things: what I'd feel like when it was gone, and how I was going to get it out. Neither was an issue. I felt fine when it was gone, and unbelievably I pulled it out myself, based on instructions with the kit. Then you mail the device back in to the manufacturer. Mine was a different brand, but it sounds like the same thing. I am definitely requesting this again when I have my second TKR in July!