Hi @cmquigley Welcome to Connect.

The first thing I thought of when I read your post was a possibly allergy to the cement used in the TKR. There is a discussion about this type of sensitivity here:
https://connect.mayoclinic.org/discussion/need-tkr-and-had-positive-allergy-testing-bone-cement-and-metals/
Also a discussion on swelling and stiffness here:
https://connect.mayoclinic.org/discussion/swelling-and-stiffness-3-years-after-total-knee-replacement/
I hope one of these will resonate with you and that you might be able to find the cause of this. From what I have heard here, most doctors expect a patient to wait a year after a TKR to get a second opinion. You are getting close to that. If the surgeon who did your TKR is not supplying any answers I would seek that second opinion from a doctor at a different medical center -- doctors at the same medical center often will not contradict a colleague. If you live within reach of a major medical center the doctors there have seen virtually everything so they often are better at figuring out unusual problems.

I have had two TKRs and never had anything like that. I had a normal amount of swelling initially but it subsided fairly quickly. It is definitely not typical to still be having it at 9 months.
I am definitely interested in hearing what you can find out about this, I hope you keep us up to date.
JK