What Causes Red Sore Bump On Tibia After Treating Fracture?

Eight years ago, I broke my tibia and fibula in a car accident. Four days later they did surgery and put a rod through my tibia from knee to ankle. Additionally, and likely unrelated to the current problem, 2 weeks after surgery they found that my heel and ankle were shattered and a metatarsal bone was also broken. I ve always had a small bump (little bigger than a pea) on my tibia where the break was, but figured it was scar tissue. In the past month, however, it s gotten very sore, very red and blackish, it swells to about the size of a small lemon and is warm to the touch. It hurts whether I m walking or just sitting. Walking doesn t seem to make it hurt worse. I have an appt. with ortho surgeon who did the original surgery but that s not until Monday. I m hoping I could get an idea of whether you think this is more serious.