Our sincere condolences in your loss. Any and all operations (even the simplest) have a certain risk. Death is always one of those risks.
A recent study of Medicare claims for adults age 65 and older lists death rate for primary total knee revision as 0.7 percent. This is a very low figure. The death rate after a revision surgery was almost double that (1.1 percent) but still very low.
Complications during the 90 days after surgery are low but serious. Pneumonia, blood clots, infection, and heart attack are the most common.
As more and more people have this operation there will be fewer overall complications but more people affected.