WSK

What the vets are telling you was true in my case. Your story is virtually identical to what we went through. Backyard, age, and options. We chose the lateral Suture procedure and it worked well, but within a year of recovery, his other leg went. Fixed that one too, but he was never the same playful dog. Absolutely no regrets about any of it. He was with us another year and a half.
Don’t know where you are, but prices seem very high compared to what we paid here in Cincinnati. We called around and found large differences here in town. Suggest you do likewise and see what you find.
Good luck.