Why can people with diabetes develop problems with their feet?

So the main problem is neuropathy. A minor element, sorry to say, because you are a vascular surgeon is poor blood supply. So if you can imagine what it's like when you've been sitting with your legs crossed or sitting, you know, kneeling for a long time, and then you try standing up, you can't feel things properly for a while, and then you get a bit of tingling and your sensation comes back. Well, that's basically what happens to people with diabetic retina, with neuropathy. They don't feel pain or sensation, they can sometimes describe it as if they were walking on cotton wool. Now pain is a very important protective sensation. You can be walking around and someone's left a Lego bit on the floor and if any of you've stepped on the Lego bit you know how painful that is. Well patients with diabetic retinopathy can have nails go through their foot. I know of one case that I looked after who had a horseshoe nail through their foot and had no idea that they had a horseshoe nail through their foot. This is the level of numbness that you have. Now that then comes to the next problem. Your skin is a very important barrier to entry of infection and if you have have diabetic neuropathy, you don't feel things. So for example, say for example, you're playing a sport such as tennis, and you can get a blister on your hand, you'll feel that blister because the racket is moving around in your hand. If you are wearing, say, sandals, your foot will move around in there and you'll get a blister but you won't feel it because you've got neuropathy and then that blister will break down or you'll get hard skin building up on there and that will then put pressure internally and then you'll get an ulcer forming. An ulcer is just a break in the skin surface. Once that skin surface is broken all sorts of bugs get in which aren't supposed to be there that may sit on the outside of your skin but once they get in the problem is they cause inflammation and they can get into the bone. Once they get into the bone, your bone can become very fragile and it can break and you need a long course of antibiotics, at least four weeks, usually about six weeks, but the bone is also quite fragile at that time so it can become misshapen. The other issue is that your nerve supply tells your body or tells your feet about their position. So you can have problems with walking and your gait being very unsteady because you don't know where you're putting your feet. Also your foot can move in areas that it normally would not do and that can cause small breaks, minor fractures that you don't feel and then that sets off a process where you get further breaks and what's called remodelling and you get a misshapen foot and the bones come out of their normal alignment that then puts extra pressure on your foot and that can lead to ulceration and again leading to infection and unfortunately with infection it can be very serious and sometimes it doesn't respond to antibiotics and you end up having amputations.