I know with Luke, there were times that he couldn't get up at all....he was over 100lbs at the time....But with the meds that he is on and gluco. pills and supplement mixed in his food, he is doing soooo well! I think you may be surpised at how well she does on meds. BUT it is up to you...if the meds don't work, and others don't work, etc. OR if it is just too much for you...that is your choice.
With Luke....I told myself that if these pills don't work, and there is nothing else....as I know $5000 for surgery is too much for us....we would have to let him go. OR if he gets to where he can't even move or play or enjoy his life, we will let him go.
It is so sad and I feel your pain!

She is older and most bigger dogs don't make it up there in age.
My thoughts and prayers are with you and her!