I am 3½ weeks out of a patello-femoral replacement. I have done very well so far, except for pain in my quad muscle and then random stabbing pains in my knee. I have almost full range of motion back already. However when I bend my knee, it hurts to straighten it out. I don't know what is normal. There are times I am almost in tears. I try not to take painkillers unless absolutely needed due to allergy to NSAIDs. My quad muscle hurts almost constantly. Is this normal? I have trouble sleeping and seem to be getting depressed due to this.