One of my dogs had grade IV LP diagnosed as a young dog in both of her legs. She had surgery at age 2 on one of her legs, but the other leg never required it and she is 11.5 years old. I recently (like 3 days ago) started her on Cosequin but have not give her any supplements in all these years. I also did not really restrict her activity all these years. On xray, she shows no signs of arthritis despite the condition. It really depends on the dog.
I agree that I'd only let a boarded veterinarian do LP surgery on my dogs. You can find out if one is a diplomat of the American College of Veterinary Surgeons by visiting their website at
American College of Veterinary Surgeons