if his meniscus was left in then yes it could be that. I don't think those fixes "break" so it may just be sore and not related to the knee as well. I don't think it's unsual for some limping to happen in the future but generally not related to a break in the surgery (or need to re-do it). Other than meniscus. My friend has TPLO on her dog's knees and they did end up going back in to have the meniscus removed (and then back again to remove the plate, it was like 4-5 surgeries total on both knees).
hopefully he is just sore from the fall and it's nothing that needs "fixing". Crappy way to spend a vacation though (worrying about your pup)