This may sting just a bit.

This, my friends, is an Amputation Knife, c. 1750.

At this point in medical history amputations were the recommended cure for gangrene, infected limb, fractured bone and charley horse.

The procedure would go something like this:
First, both the patient and surgeon socked away several slugs of the strongest grog in town. Next, the patient would be secured to a table – either by leather straps or a few muscular assistants. Then the surgeon – whose qualifications included ownership of a sharp saw and reputation for hasty work – would get down to business, doing his best to ignore the screaming and the stray dogs lapping blood off his floorboards.

This instrument of medical carnage is curved because surgeons of the era 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 de rigueur because they made it easier to leave a flap of skin that could be used to cover the exposed stump.

Personally, when I look at the thing I can't help thinking of Toucan Sam.