My senior has had it now for a few years. It started with his walk being off. He wasn't what I would call limping but he was also not being very steady on his hind legs when I stood him on them while rinsing him off during a bath. He only has it in one of his legs so far and sometimes the joint pops out of place and then he cries terribly. I then pop it back in place by slowly rotating the affected hind leg. Let your vet show you how to do it!
LP can later lead to arthritis as well. I give him Glucosamine. That will help stage 1 and 2 LP. State 3 and 4 will need surgery. If your dog got it when he was older and if it pops out only sometimes than it's probably stage 1. Hope this helps