One of my dogs had a version of the CCL (ACL in humans) correction surgery, so I did quite a bit of research online looking at the options. She's the first dog I've ever had, so putting her to sleep without first picking up a second and third job to pay for whatever she needed just wasn't an option for me (of course, we've also got ferrets and routinely drop big $$$ on their vet bills, so perhaps I'm just nuts).
I'd hazard a guess that the surgery your vet is suggesting is the NTPL.....basically it's patented by the inventor and the surgeon must go thru one of the inventor's certification courses to perform them. It's typically used for larger dogs because the other surgeries don't tend to last because of the weight. It involves actually flattening the bottom bone of the knee being repair, so that the top bone doesn't slip off, which is what happens when the CCL ligament is torn (or in our dog's case, just plain gone....three tiny strands left).
The cons of the surgery are a longer recovery time, the expense, and the crowd that says modifying the bone is just plain wrong. On the plus side, it *seems* to be about the only thing that lasts for larger/heavier dogs.
Other surgeries tend to construct a new ligament with artificial filament or similar material. There's a couple of varieties, but essentially the surgeon constructs a new ligament like structure to keep the knee in it's place. Our dog (a ~50 lb pitbull) had this surgery. The pros are a quicker recovery and lower price, cons are that it probably isn't sufficient for a larger dog and you *must* keep your dog from blowing out his/her new knee by over-exertion.
A friend of my wife had their larger dog repaired using the non-NTPL technique and I can tell that the repair just isn't doing the trick.....it still limps around and often doesn't put any weight on the knee at all.
Doing nothing is actually recommended by some websites online, who believe that strengthening the leg muscles will correct the problem. As much as I wanted to believe them, I came to conclude it just isn't true.....but rehab after whichever surgery is very important and muscle strength there does help quite a bit. I try to take my dog for walks or short and *slow* runs, which she loves. Just not too much too soon.
Just FYI, I also investigated braces......there's many types and kinds but most appear to be a crutch, not a fix. We opted out of them because we figured they'd get chewed off
.
Oh, and it is true if you don't get the knee fixed up, the other will likely get worse, often quickly. Actually, our dog went in for one knee and wound up getting the other knee done instead as it was worse when the surgeon did his tests on it. After getting the one knee fixed, the other knee seemed to work better and we've been able to hold off on surgery for that one.....I think it was just one would hurt and cause her to put more weight on the other one, which would then hurt and cause her to put more weight on the first, rinse and repeat.
Lastly, getting your dog back down to a healthy weight if he/she is overweight is critical......ours went on a diet and has been on one for quite some time now, which she is *not* at all happy about. But, since she's lost the weight, most days there's not even the hint of a limp on either leg. Shame on us for letting her get that way, I know, but she looks downright skinny at her ideal weight.
Hope the info is useful. Good luck.