Getting it done due to stiffness/lack of bending/arthritis- only one knee, other is fine. Confused about the continuous passive motion (CPM) machine. Don't I need to use it at night too when I sleep? The rep for the CPM machine said they don't recommend using it at night (they don't recommend putting it in the bed in case you move a lot normally during sleep). I'll check with Doctor, I thought he said to use it as much as possible both night & day, while also doing the PT exercises as much as possible. Anyone have a Total Knee Replacement recently?