New to ortho - HELP!!

Hello there! I am new to ortho surg and trying to figure out a claim... Pt had surgery (25606 & 29105), then came for post op - 20680 was coded w mod 55 eventhough our provider was the surgeon... as far as I know, 55 mod will be appended only if our provider is taking over post op management only! If any mod is to be used I would say it's 59.... Am I correct or should do some more research? Any input would be much appreciated! :)