Ok thanks. That is the preferred method.
Most dogs are walking within a day or two of the surgery. I would wonder whether there is a torn meniscus that is causing the chronic pain. The other thing to consider is whether the implant itself is causing pain or there could even be an infection at the site of the plate.
I'm surprised the surgeon doesn't want to look deeper into this and find out what's causing the chronic pain. These dogs should not be holding up the leg. They will get arthritis in the joint, but that's usually years down the road, not this quickly.
I would talk with the surgeon about why there is a chronic lameness and whether or not the meniscus was removed. If they're not all that receptive, then I would find another surgeon in the area and get a second opinion. They can look at the previous x-rays to determine if it's a problem with the implant.
Any time we see a lameness or holding up the leg, those are signs of pain. I would probably have him on an anti-inflammatory like Rimadyl or something for more chronic pain like Gabapentin or Tramadol. That should help with his comfort while this gets figured out. Ultimately, I think he'll need the knee re-explored to either remove the meniscus or remove the implant to see if that resolves the lameness.
I hope this helps, let me know if you have any other questions.