What causes diabetic to need amputation?

Low blood flow: Calcification & narrowing or blockage of the very smallest arteries results in low blood flow, low oxygen, and low nutrition to the site. Most common affected are feet & toes. Low blood flow, tissue trauma, skin ulcer formation & infections result in infected, dead, or gangrenous tissue at the site. Serious infections or gangrenous tissue can lead to amputation if unable to be corrected or healed.

Many factors: Diabetics often have issues with sensation or feeling and may not appreciate repetitive trauma. Diabetics also have more difficulty with infection, and may have decreased books flute as well

Lack of sensation: Diabetics loose the normal sensation in the feet. This makes them prone to small trauma that, left unattended, results in infection potentially threatening the limb. Also, uncontrolled diabetes makes people more prone to circulation problems and infection (and infections getting out of control). Foot protection (always wearing protective shoes) and careful daily foot inspection is critical.