
He probably is still a little stiff & sore & it probably aches when he's tired, but he may also have got into the habit of not putting his weight on that leg because it hurt him to do so. Also it will take time to build up the muscle he hasn't been using. Once he's fully recovered he'll forget all about it.
Why don't you take him back to the Vet, just for a check up & to ease your mind?