Amputation is necessary when parts of the foot die – the toes or even the whole foot. That way, the area is not going to heal unless you cut the foot back or the leg back to a point where there’s good blood flow, then the skin and the muscle and the bone will heal. Otherwise, you’re just going to have areas of dead tissue that might be sources of infection and also it’s not a useful foot anymore because those dead tissues can’t be used, the muscles can’t be used, so you really need to cut that off and then fit the patient for an artificial limb – either an artificial foot or an artificial lower leg – that enables them to walk again.