I had a full knee replacement this past summer and I did not have much pain. I had to wear a brace the first 5 weeks because of instability. I almost always cut sitting down. I just make sure my table is lower or my chair is higher so I am looking down on my cut. Also you do have to watch the angle of your rotary cutter to make sure it is going through all layers. I also could not do it for a long time when my knee was bad because of swelling, I braced it up on something when I could but not always. Good Luck