Infection for knee replacements is rare, 1%, and even that can be treated with IV antibiotics. For hip replacements, the rate of infection is even lower.

Infection rate is a function of how long the surgery takes. Infection is more likely to happen during a three-hour surgery than a one-hour surgery. But death resulting from an infection during surgery is extremely rare. It certainly does happen, and it's tragic, but IMO it should not prevent anyone from having a necessary surgery.