DH
".........your question sounds like a typical journo trawl (not a criticism, only an observation), because it is impossible to answer, except to say that if there were any "known structural issues" as you say, the aircraft would not be certified to operate."
Before making such a comment, maybe you should have researched these aircraft and the significant maintenance AD's. As KK has said, there is a major spar inspection program for these types.
Sorry to disappoint you, but definitely NOT a journo - been flying heavy aircraft for over 30 years.
Whatever the cause, it is a terrible tragedy.