BOSTON — The younger sister of the 8-year-old boy killed in the Boston Marathon bombings has undergone what her family calls a "milestone" 11th operation on her left leg, lost below the knee.The family said in a statement the operation Wednesday on 7-year-old Jane Richard at Boston Children's Hospital closed the wound and will allow for the fitting of a prosthesis.Her brother, Martin Richard, died.The family says Jane has also had to deal with infections and faces more operations.