I agree that most fighters do not come in at 100% and almost all fighters have pre-existing injuries they put up with. A broken rib is something else though and had it not been so close to fight-day we would have seen it post-poned for sure.
Also, OC 335i, I'm not sure if that pic of Sonnen's face is from the Silva fight or not. I distinctly remember Anderson slicing a cut open over his left eyebrow which looked very nasty and it's not visible in the pic you've posted. I could be wrong though.