Well usually when they do this type of surgery, they tend to notice right away if something else is wrong, so I doubt there was any kind of tendon damage at least. Cartilage, might be a different story, but I don't think we would have seen as much of KG even on the bench if that was the case, and especially not playing in a couple more games in the regular season.
My guess is that somehow when we played Utah a bone spur broke off or something and got lodged in the knee somewhere. Then again, I don't know much about bone injuries and I'm probably talking out my ass.