I’m not sure about the Ortho, but have you taken him in to get checked by the Vet?- They can determine what stage he is. Your local Vet might also know of a well known Ortho in your area.
My 5 year old has LP in the back right. Well he has it in both knees but one is worse than the other.
You can start him on some Glucosamine supplement. It will help a little. Peanut has been on it and doesn't “skip” as much as he did off of it.
Cosequin for Dogs | Combines Glucosamine & Chondroitin