Hi, i have been having a pulsating feeling behind both knees for a long time now. it generally feels as though it is throbbing but in time with my heart beat, and along with this comes very deep pain. it is normally worse at night and is virtually not there dduring earlier hours of the day. my knees are also purple in colour with darker purple patches , which flow out to the sides of my knees in a way that makes it look like corned beef skin . i dont know if its relevant but i also get very deeply rooted thigh pain, where it feels as though it could be my bones that are aching because it is not on the surface. not too long ago i also got a place near my shin that felt like a bruise and was very painful to touch even when bedsheets were passed over it. this left over night and did not leave any form of mark to indicate that a bruise was ever there, however once again i dont know whether this is related to my knee problem im just trying to give you better ingisht.