Did you have a drain after surgery? I find that folks who don't have a drain have increased pain about a week after surgery as the bruising starts to come to the surface. The bruising sometimes starts fromt the toes all the way up to the back of the thigh. Also, sometimes patients have increased pain as the MD's close the wound with an anesthetic that gradually wears off.
Nonetheless,call the doctor. When do you go to your PT? They might be able to assess also. Keep icing your knee. Place a pillow between your knees when lying on your side operated leg up.
What medication were you taking at the hospital? Perocet only or were you having Morphine/Dilaudid for breakthrough pain?