You might think your HMO plan is scary, but at least it doesn't use these vintage surgical instruments...hopefully.

Amputation Knife (1700s)
Knives used for amputations during the 18th century were typically curved, because surgeons tended to make a circular cut through the skin and muscle before the bone was cut with a saw. By the 1800s, straight knives became more popular because they made it easier to leave a flap of skin that could be used to cover the exposed stump.