Thank you for using JustAnswer.com, I'm Dr. Dan and I'll try to help you.
Is this what your pooch's paw pad looks like? Or close too it?
I "have a picture of your dog's paw" because it is very common with many dogs. It is called hyperkeratosis (Hyper = a lot or more than usual, keratosis = skin production) literally means extra skin growth. This can happen for many reasons. If that is on the leg that had the TPLO I strongly suspect that it is due to the fact that your pooch has not been using his leg as much as usual and doesn't wear down the tissue (makes sense during a post surgical recovery). This can even be seen around the edges of all paw pads in some "normal" dogs and not in others depending on the manner in which they walk on their paws. For most dogs this is technically abnormal but not due to disease and usually requires no treatment. I suspect that once your pooch recovers 100% it will wear down again and disappear.
Now, there are diseases that can cause this like lupus and lupus-like diseases, so it is a good idea to have your vet check it but it can wait for an open appointment in my opinion. Best Wishes.
Dostor Dan; Thank you for taking the time for the "feedback" and for the well wishes. We'll need those as Fiona is a dog to whom "if it can happen-it will". I'd looked at several websites for something to help identfy this and I suspected the hyperkeratosis description. I'm very glad I tried the Just Answer and feel like I have good back up when I can't reach my own vets. Thanks again and kudos for your service. Customer/p>
Absoultely, it's clients like you who make this website and our profession rewarding.