I would avoid translating this as a term and think of the overall context. I would avoid using "post-traumatic pain syndrome" unless there was more information. It sounds a little unnatural in this context and a syndrome is a group of symptoms.

For the sentence provided I would go with something like; "there is strong and persistent pain associated with broken ribs and post-traumatic symptoms of the head and neck"

http://medical-dictionary.thefreedictionary.com/post-traumat...