By now the injury must have been dealt already and overtime its already cured. If its not the fist that's broken, it wouldn't be a big deal in the fight. Inoue is not old yet, there is no way he can't get used to the weight after few months.
One more advantage with this fight is that Fulton vs Inoue fight will be held in Japan. He'll do his best to impress his fellow country men to give them an spectacular KO.
On paper, it seems that almost all advantages are pointing towards Naoya Inoue, leaving the current 2-belt champion, Steph Fulton, as the underdog in their upcoming bout.
Personally, I cannot really bring myself to oppose whatever is laid in-front of us now and favor the champion because even if Inoue is just the challenger here in Fulton's division and this is his first fight at 122, it's just real hard to go for the opposite way and bet against the crowd favorite.
It might be hard to think about the possible outcome for now because I also don't want to underestimate Fulton, but in this instance, I will go with the Japanese monster.