Hmmm. Well, I've broken several of MY bones, and in my experience, a "clean" break is NOT a good thing. It makes healing harder, as the edges of the bones broken are SMOOTH. They have nothing to hold them in place, which is why they're talking surgery, to put plates and/or screws in there to keep it stable so it can re-knit.
I almost had to have surgery on my arm for the very same reason, but my Mom was very vigilant about keeping my arm very very still so that the bones could heal. Lucky for me, my doc saw improvement after a few weeks and no surgery was needed. It's much harder to do with a doggie, since they have no idea why you want them to be so still and you'd have to drug them for them not to move that limb
After 5 weeks, there should be some bone knitting going on there. What I dont' get is why they told you that things were good with the Xray, then the doc says no, they're not
I'd ask to see the xrays. If it's healing well, you should see it's all blurry and looks almost knot-like at the break, meaning that the bones are knitting themselves together.