
My boy had TPLO in 2006. This
surgeon has a nice description of the surgery. (he's also a very nice vet that answered some questions for a distressed owner in the UK!)
Glucosamine on its own does nothing for me (bad knees myself). I always make sure I take it with chondroitin and that the dosage is high enough. I get 1500mg a day; that's about how much I'd be giving a 78Kg dog. I use the human stuff as it's cheaper. But I buy quality human supplements, not just the supermarket stuff. That does nothing for me so I've assumed it wouldn't be as helpful to my dog either.
Find a pool. Hydrotherapy post surgery was a godsend for my boy. Discuss it with your surgeon and find a good hydrotherapist. He started with only a couple minutes of swimming but we increased it slowly and it encouraged him to start using the leg again. It was very helpful in rebuilding his muscle tone (he'd been off that leg for about 5 months)
It took months before he was able to run hard without limping afterwards but he got there. He's a 40Kg golden retriever and dashes around the woods like nothing ever happened to his leg.
Good luck with your boy.