At which level should the amputation be done? continued...
A below-the-knee amputation is usually preferable. It provides better mobility. Even if a person is very unlikely to be able to walk because of their general health or other medical conditions, a below-the-knee amputation provides for easier transfers and movement while in bed. Walking on an above-the-knee prosthesis (artificial limb) requires a lot more energy than walking on a below-the-knee prosthesis, although young, relatively healthy people manage much better than older, more frail people do. But when a below-the-knee amputation cannot be done, an above-the-knee amputation has the advantage of easier healing.
Sometimes a bypass grafting operation may be done to allow a below-knee amputation site to heal adequately. The most important thing in deciding whether a below-knee amputation will heal is the clinical judgment of a knowledgeable surgeon.
When is the right time to operate?
In general, amputations for sudden ischemia (when a clot develops and completely blocks blood supply to an extremity) are done to control pain soon after the preoperative evaluation is finished, if possible.
Bypass surgery or angioplasty is always done when possible. Amputation is the last option.
Noninfected gangrene of the fingers and toes can be treated by amputation or can be allowed to "autoamputate" (tissue dies and sloughs off on its own) over a period of time, usually months. Gangrene of other extremities requires amputation.
Infected gangrene should be treated with the goal of getting rid of the infection yet preserving as much of the extremity as possible. Dead or dying infected tissue should be removed (debridement) as quickly as possible. Tissue that is infected but may likely heal should be left. And the person should receive intravenous antibiotics.
If a person is not stable or does not respond to antibiotic treatment and debridement, amputation must be done rapidly. A first emergency amputation is often done with the goal of stabilizing the person. And a second elective operation may be done to remove any further dead tissue and to improve the function of the remaining limb.