Few surgical procedures have as high a patient benefit to procedure time benefit ratio as ankle disarticulation and guillotine below-knee amputations for foot sepsis. In contemporary major amputation series about 15% of patients necessitate an initial guillotine procedure before conversion to higher closed amputation level. Usual indications, contraindications, and considerations (ankle disarticulation vs. guillotine below-knee amputation) for a staged below-knee amputation include:

True foot sepsis (undrained infection with systemic symptoms/signs such as rigors, fevers, altered mental status, tachycardia, hypotension, ascending cellulitis and lymphangitis, leukocytosis, hyperglycemia, etc.) must be addressed emergently with parallel medical and surgical interventions. Often the initial surgical assessment focuses on determination of amputation level (above vs. below knee). Pulse examination is important even in this setting since occasionally a staged revascularization after the sepsis drainage is indicated to save the knee. As patients are directed toward emergent surgical drainage, they also undergo resuscitation, administration of parental broad spectrum antibiotics, aggressive correction of metabolic abnormalities, etc.

Not infrequently patients may arrive pharmacologically anticoagulated for various indications. On a case-by-case basis, most disarticulations and guillotine amputations can be performed without full reversal and without a tourniquet.

The patient is positioned supine and prepped/draped to the knee since occasionally unexpected ascending calf sepsis is encountered. No knives are necessary on the field since the electrocautery offers good hemostasis safely for the skin and soft tissues, and the eventual healing goal is not at the initial first-stage amputation level. The pace of the procedure should be rapid in view of the acuity of setting and patient illness. Not infrequently there is hypotension after induction of anesthesia due to the septic hemodynamic state, thus time under anesthetic agents should be minimized. If unusual organisms are suspected, then cultures can be obtained from deep tissues once the specimen is on the back table, but not infrequently these infections are polymicrobial and demand broad coverage empirically.