I sprained my ankle really bad, during a snowstorm I slipped on a storm drain and turned over on it as I was walking to my office. I had to spend the whole day on my feet. I kept a pair of hightop sneakers in my office so I changed out of my boots. By the time I was ready to go home my foot had swollen so much I could not get the boot back on. Later I saw my toenails turned black.