Heck, how do they explain how Rocky hurt his eye in the first fight, has the operation, is told he could go blind if he fights again, fights anyways, beats Creed in spite of Adrian's initial misgivings.
Then, Adrian is totally silent about the eye as Rocky then has 10 title defenses, gets KOed by Clubber, beats Clubber, then beats Drago. 13 fights, and not a word about the eye.
And don't get me started on how he sucks at commercials in the second movie, does American Express and other commercials in the third movie, then says he's "not a commercial-type of guy," in the fifth movie.