3-Tut could not have died due to the break to the leg bone (this cannot cause death) and no sign of infection was detected in the soft tissues in the area, so he could not died for such an infection.
That's not what the report says actually.
The part of the team that subscribes to this theory also notes a fracture of the right patella and right lower leg. Based on this evidence, they suggest the king may have suffered an accident in which he broke his leg badly, leaving an open wound. Although the break itself would not have been life-threatening, infection might have set in.
There is no agreement among the researchers. Some say that there may have been an infection. Others claim there wasn't.
The report doesn't say this, but a wound could cause "blood poisening" (I don't know what the english term is). This would not show up as an infection at the wound site, but is actually lethal. (I actually know someone who had something like this happen. On his arms you could only see scratches, but there was this bright red line on the interior of his arm. He needed medical treatment for this. In the old days I think this would have killed him.)
But you are right I think in pointing out that he still could have been poisened.
I thought it was rather interesting that the scans answered some questions and then turned right around and posed some more questions