Congenital limb difference is when the limb(s) does not completely form or grow at all as the baby develops in the uterus. The exact cause of the congenital limb difference is not known. The chances of this birth defect happening can increase if the infant presents with genetic abnormalities, growth restriction, exposure to certain viruses or chemicals while in utero, specific medications, or exposure to tobacco smoke.
A traumatic amputation occurs after an experience from a motor vehicle, occupational or industrial accident, or combat injury. The limb that is lost is cut off or separated in a severe accident and cannot be saved for several different reasons (burns, crush injury, damage). Traumatic amputation is the most common and accounts for about 45% of the amputee population.
A surgical amputation occurs when the tissue of a limb is destroyed due to infection or disease and is impossible to repair or endangers the individual's life. Diseases or traumatic events that cut off blood flow to the limb for extended periods also cause the need for surgical amputation due to the tissue dying (i.e. frostbite, diabetes, septic shock, etc.)
An elective amputation occurs because an individual would rather not be in the position they are in due to specific injuries or other difficulties. The most common injuries that result in an elective amputation are stroke, failed surgeries, brachial plexus injury, etc. Before the amputation, the individual should meet with their physician and a prosthetist to assess the best amputation level given the individual's occupation.
https://www.armdynamics.com/upper-limb-library/elective-amputation-of-an-upper-limb