I am 65 years old, and this is the third time I ve had a bruise (blood pool) around my knee with no preceding injury. 3 days ago, I awoke in the middle of the night to a severe burning pain in my upper thigh. The next morning, I had a bruise about 4 inches long by 2 inches around the interior portion of my knee cap. The next day, the bruise had grown to completely under the knee cap and around the bottom of my knee, and the bruise is now about 4-5 inches in a circular pattern under and around my knee. I have had two hip replacements and have had consideral trouble with this particular thigh since the surgery, 5 years ago. Should I worry about this bruise? my Doctor or Dr s assistant. looked at me stumped, and said he had no idea what it was. Should I be concerned? or is this just a vericose vein?