My dog has avascular necrosis. Is it Legg-Calvé-Perthes disease?

You are correct those names are used for the same condition. It is typically more common in young, small breed dogs, especially Terrier breeds, but can also occur after trauma. I am assuming your kid has some lameness of the affected limb which is what prompted the vet visits and the xrays. Unfortunately I cannot provide additional comment on the x-rays because it is not legal for us as pet coach experts to diagnose without having examined the pet. But, I hope to provide some information that will be helpful. If the x-rays have not been evaluated by a radiologist this could be very helpful in determining the need for surgery. If this is Legg calve Perthes, in patients that don't respond to medical management within 4 weeks, surgery is typically recommended. For small dogs this typically means removing the head of the upper leg bone (femur, an FHO). For large dogs sometimes a total hip replacement is required. I have attached a link that hopefully will help to explain a little bit about this disease. This is not something your environment caused so it is safe for Boo to stay in AC. I also think the other supportive care that you are providing at home is still a great idea for overall joint health and his other joints. I hope this helps and thank you for using Petcoach!

https://www.petcoach.co/article/legg-calve-perthes-disease-in-dogs-avascular-necrosis-of-th/