Hello and welcome to the forum. I did once have a read up on this as I have a terrier who hops. She does not seem to do it as much these days thankfully and the vet thinks her patella are okay. From what I can remember when researching, it is one of those conditions which should be monitored and treated according to severity.
If I recall once it gets to stage 4, surgery is required as it will be painful for the dog. Your vet should be able to advise better as beyond some research on the web, I do not have any experience with this condition. I would advise speaking to the vet ASAP though. As with the cruciate ligament problem, which Dottie's dogs suffered from, delaying surgery could cause more complications. Good luck.