I had replacement surgery on one knee in Feb 2010 and found that eventually I could stand longer--but need to do my knee exercises daily still in order to be able to stand--or anything--for very long. I cut at a table that is high enough that it hits at about 3" above my navel--it's an old drafting board, but have friends that use bed risers under the legs of their tables. That also allows me to use a stool if I want and need some relief for my knees. after my surgery, it took a good 6 months to get back to normal, and now the other knee needs replacement! My PT also recommended a gel ice pad that allows me to use when the knee gets swollen--even if I'm doing stuff. good luck and don't give up.