So very sorry to hear about Katie's leg problem. I hope it can be fixed quickly.
In the past, my RB Great Pyr Avalanche had an ACL rupture and had the surgery to repair it. The hard part is recovery. Keeping them off the leg is almost impossible. My parents present rescue Great Pyr, Smilie, had the luxating patella surgery done in both legs before my parents adopted her.
My prayers are with Katie!