Annabelle Williams, who is missing part of her left arm, will be the stunt double, and Charlize Theron will portray a character with a similar physical trait. Here are some excerpts from the article:
"In December last year, the producers of the yet-to-be-completed film were looking for an athletic, blonde woman with half an arm to be the stunt double for one of Hollywood's most glamorous women. It was a perfect match for Williams, whose left arm ends just below the elbow. In the film, Theron's character will have part of one arm missing. Williams will fill in for the Academy Award-winner during a fight scene."
Annabelle Williams had this to say:
"They are going to film me from a very long distance for the fighting so that they don't have to CGI out her arm. I will be her, but just not [in] the face."
Williams also told the site she has been training for Mad Max: Fury Road for the past six months.