I'm not talking about a scripted quest sequence, but something that happens in any combat. You may lose a limb or get disfigured, and you go the rest of the game with a makeshift prosthetic or just go without it, and your dog can help you out. Unless you're able to find/afford a cyborg replacement limb from some doctor of the Institute or other high-tech organization? Think of it as a super cripple feature, the new limb you get has advantages/disadvantages depending on what type you get (a robot hand may make you stronger but less agile).