Kimeo, I am so sorry for your recent loss of your dear girl.
When they pass, it seems we all feel we may have done something wrong, especially at the end.
There are always some "what-ifs" and heart rending questions which go round and round in our minds.
The truth is -stage 4 kidney failure is very serious. And sadly, there is no cure by that stage. Kidneys can never repair themseves and the disease can never be turned around.
The end is not far away, it may be days or it may be weeks...and if they are allowed to live to the very end, they become horribly sick, as their whole systems are literally poisoned by substances in the blood which the kidneys can no longer remove or filter.
They have constant nausea, sometimes painful mouth and stomach ulcers, apart from other symptoms including confusion, and end-stage patients often will not be able to even hold down water.
So there always comes a time when euthanasia is necessary in order to prevent further suffering.
You let her go before she got to that stage, so she never had to experience it.
Dogs are very stoical and can behave pretty normally even when they have a terminal illness (as indeed, your girl had)
She hadn't yet got to the stage of being unable to eat or feeling desperately bad , and you protected her against that.
Blessings to her Soul. She won't be suffering where she is, her leg will be fine again and she will be well now she's free. She will continue to love you and will be waiting for you, believe me. My dog has already shown me that is the case, and that they do live on in Spirit.
My condolences to you.