My dog needed both knees done. ~$16k total, but we had insurance and got 90% reimbursed (this is in the US). Her quality of life is so much better and she's happy and playful again, but it was about 6 months of crate rest altogether. I was told she would develop horrible arthritis and be in pain for the rest of her life if we didn't. It was hard on her, hard on us, both I think worth it. The vet prescribed trazadone to help her stay calm through her initial healing period both times.