John, I don't know why you ask this question but I will say that ED is a SOB of a problem. Mine has it bilateral, diagnosed at 7 months surgery at 9 months and a real PIA since. complicated joint AND they carry the majority of the weight. Add that to a high, high energy dog and it's really heartbreaking, that is if you get attached like i do.
From reading - 4-6 moths of age is fastest growth, bone plates are very soft and succeptable to injury. Don't let the dogs jump from truck , ever, hell my knees hurt when i jump outa the bed and i'm only 40. just not worth the chance.
I should add breeder was great - gave me purchase price back, and worked out a deal that a verbal promise that i not breed him and me sending the papers back to them without requiring neutering him. I didn't want to neuter because of the potential of added weight.