Wikipedia editors must have gotten really pissed off that the 300% stuff is apocryphal. They only mention it at the very, very bottom of his page.

Robert Liston

Liston’s most famous case

Although Richard Gordon’s 1983 book pays tribute to other aspects of Liston’s character and legacy as noted elsewhere in this article, it is his description of some of Liston’s most famous cases which has primarily made its way into what is known of Liston in popular culture. Gordon describes what he calls Liston’s most famous case in his book, as quoted verbatim below.

Amputated the leg in under 21⁄2 minutes (the patient died afterwards in the ward from hospital gangrene; they usually did in those pre-Listerian days). He amputated in addition the fingers of his young assistant (who died afterwards in the ward from hospital gangrene). He also slashed through the coat tails of a distinguished surgical spectator, who was so terrified that the knife had pierced his vitals he fainted from fright (and was later discovered to have died from shock).

— Richard Gordon

This episode has since been dubbed as the only known surgery in history with a 300 percent mortality rate. The situation that Gordon labels “Liston’s most famous case” has been described as apocryphal. No primary sources confirm that this surgery ever took place.

I think some Wikipedia editors must hate Reddit more than Hexbear does.