I have a English Springer Spaniel who is nerly 4 and needs double knee surgery, has anyone experience of this?

I have just been told by my vet that my ESS has major issues with both knees, small pieces of bone seem to have broken off and obviously she is in pain, walking seems ok, but going up stairs or jumping on setee is impossible, squeels with pain, this has only just become evident as a problem, although vet said probably been like it for 6 - 12 months, presumably just got a lot worse, hense pain. Has anyone else experienced this problem, vet tells us this could cost �10 k to put right, he can't do it she would need to go to specialist, we don't have pet insurance or �10 k so may have to have her put down, which would be truly heartbreaking. Can anyone help? We are desperate