I had total knee replacement surgery on the 12th of Dec. I came home on the 14th and now I m on Percoset - 1 every 4 hours. I have two pain problem issues: after an hour on the CPM machine, sharp knife slicing kind of pain develops just to the right of my knee cap and that whole area. I then have to get off the CPM machine. Also during the night in bed, in my calf, there develops pain similar to boiling heat. Only walking gets anywhere near to relieving these pains. Percoset doesn t seem to make much of a difference either way. I m wondering if this is normal in the recovery process or maybe there is something else going on.