Amputation is the removal of a body extremity through trauma or surgery. Amputations are named in reference to the nearest joint; i.e. a below-knee amputation or an above-elbow amputation. If an amputation is performed through a joint space, it is referred to as a disarticulation.
Amputation is used to control pain or disease in the affected limb. It is typically a treatment of last resort. If a disease process has proceeded to the point that the tissue of a limb dies, a combination of inflammatory changes and bacterial action can result in the dead tissue being sloughed off in a process called autoamputation. A surgical amputation is normally planned so as to leave a thick flap of skin and muscle tissue that can be folded over to cover the cut end of the bone and produce the best possible cosmetic and functional result. In cases of infected wounds or critically ill patients, a 'guillotine' amputation is performed, in which the limb is divided in a single plane, without forming complex flaps, and the wound is left open. Further surgeries are then performed to revise the stump once the patient is stabilized.
Side-effects of amputation can include psychological trauma and discomfort. Patients sometimes report phantom limb pain, in which nerve activity in the stump is perceived as pain in a body part that is no longer present.
Non-medical amputation is used as a form of punishment or as an act of terrorism.
A particularly controversial form of amputation is known as the Van-ness rotationplasty. In most cases, it is performed in the case of a femoral osteosarcoma. The procedure consists of an above-knee amputation above the level of the sarcoma. Keeping the blood vessels intact, the surgeon then severs the amputated limb below the knee. The lower leg —the tibia, fibula, ankle, and foot—is then rotated 180 degrees. The lower leg, still rotated, is then attached to the stump so that the heel is at the anterior aspect of the leg. The ankle is now used as a knee joint, to which a prosthesis is attached. This supposedly makes ambulation much easier.