What Causes Pain And Knot Under Knee After Femur Fracture?

Hi, I broke the end of my femour ten years ago. My doc from the says I'm close to a full knee replacement. In the meantime I am recieving sinvist shots for pain. I asked my doctor why my leg has a large not under my knee that looks like my shin bone. My pain is not stopping my question is why the knot and the increased pain?