It's hard to make windows into men's souls where injuries are concerned. Don't know Mikus' history, and you just can't tell if someone is injured or not from the outside.
Yet there is no question that this was a terrible play by Getzlaf, who put his leg right out there in a classic knee-on-knee pose, locking his leg. It was an awful time of the game to do it. Lack of poise and absolutely a major, to these eyes. Intent to injure isn't the important factor.
As for Mikus, I don't hope he's injured, but I do hope he wasn't just embellishing the play either. It certainly looked like a bad injury. Hopefully he can come back and play in the SF. It looks like it could be a serious ACL/MCL injury.