First of all, allow me to offer my condolences. Diabetes in unfortunately the leading cause of limb gangrene and amputation in the developed world today. It is caused by the vasculopathy that diabetes causes. When there is excess sugar in the bloodstream, the molecules attach to the lining of blood vessels and cause damage. Over time, this leads to poor blood supply and oxygenation of the tissues, predominantly of the lower extremities simply because they are farthest from the heart. Because of the poor tissue oxygenation, bacteria can set up camp and begin to divide. The natural ability of the body to fight off this infection is further impaired because due to the lack of blood flow, few white blood cells of the immune system can get to the site.
If the tissue is clearly dead and unsalvageable, it will need to be amputated. Often, if it looks damaged but with potential for healing, a vascular surgeon
will perform one of any number of types of interventions to restore blood flow to the injured extremity, including ballooning open a vessel or bypassing a section of the vessel entirely by sewing in a graft. Nonetheless, if there is no blood flow to an area (which they will check by ultrasound) and you have no sensation there, it is likely that no amount of intervention will save that part of the extremity and it will need to be amputated. As for what kind of prosthesis you will need, it really depends on where the level of your gangrene ends. As I cannot evaluate you in person, I cannot say where this would be, or even if your tissue is truly irreparably gangrenous.
If your vascular surgeon feels that it is basically restricted to a couple of small toes, there is a chance that no intervention will be necessary, as these will fall off on their own without intervention, provided there is no evidence of gross infection that could spread to the rest of your foot. You would likely not need a prosthesis in this case because it would not significantly affect your balance or ability to walk.
If he feels that it involves all of your toes he will likely perform a "trans-metatarsal" amputation, meaning he will amputate the front half of your foot. In this case you would likely want to get special shoes with blocks in the front so that the space is not hollow. These improve balance and the natural stride in a person with a transmetatarsal amputation.
If the gangrene has progressed any farther than this, a below-the-knee amputation will likely be required, in which case you would need a special prosthesis that simulates an ankle joint and has a cup into which the remaining top portion of your shin would fit. Over the years we have found that this is the amputation which provides the best quality of life and return of natural stride as opposed to trying to preserve the ankle joint.
If the gangrene is any higher, you will need an above knee amputation and a prosthesis with both ankle and knee joints. This requires significant rehabilitation and increased morbidity. It is done only if there is risk to the patient's life if the extremity is not removed. It doesn't sound like this is your case just from the brief couple sentences you wrote.
You should talk to a vascular surgeon regarding your options and possible interventions and what kind if any amputation you will need. If you do need to undergo the surgery
, there are a number of models of prostheses available and in general the medical systems are very streamlined in terms of getting you in touch with physical therapists
and prosthesis specialists after the operation to find the model that will be right for you.