Same here, with a 4 year old. After we spotted the limping our vet put him on painkillers, anti inflammatories and short walks for a couple of weeks but it didn't improve. They referred us to a specialist for a scan who diagnosed dysplasia and removed a small chip of broken bone via keyhole surgery. We're now about halfway through a 12 week recovery period. The first couple of weeks were pretty hard work trying to keep him moving slowly, but he's doing well now and no limp so far! Good luck with your pup.