In combat, situational aspects sometimes tend to interfere with consequences. In theory, the "create advantage" action allows an opponent to create virtually any aspect, from "Stabbed in the hand" to "Head lobbed off". While these extreme cases might be quite clear, it's the intermediate aspects that I'm wondering about.
For example, a character wielding a war hammer wants to create "Broken Hand" on an enemy. This seems fairly plausible in the situation, but it would also circumvent the entire stress track system to create what is essentially a consequence in nature, if not in name.
Is there anything in the official or any accepted house rule on how to deal with that? What is the best rule of thumb to avoid this dilemma?