Good morning @janieben. I think I have the same issues with my TKR from 2011. The one from 2021 is moving through life with me painlessly and supportive. And no......I haven't talked to anyone about it...yet. So it was informative to read your post.

Although I have no medical background or experience, I have learned a lot from you and other members of Connect. Here is my unprofessional thinking at this time. The culprit is aging. I think we forget that 12 years ago....our bodies were younger and more able to accommodate the elements of post-surgery recovery. We were more active and resourceful.

Then some of us undergo a second TKR for our other knee. That can put a lot of pressure on the first TKR knee to remain strong and responsive. However, it has aged normally and resists some of the pressure we put on it to support the second TKR. The resistance after "13 years" reveals itself as pain that we think is caused by a new condition.

My memory tells me that there are other issues......like using a cane for support. I had to stop grabbing a cane because the support is not equal for both sides. And in addition, I noticed that my shoulder which had undergone a reverse replacement began to resist the extra pressure from using the cane. So I moved to a rollator and the pressure from using that just ensured that both shoulders were reacting from the strain. Why? Because I had to have rotator cuff surgery on the second shoulder.

We are all facing aging discomfort. I am 81 and suffer rather miserably from SFN (small fiber neuropathy). However, my MFR (myofascial release) therapists spend a great deal of time keeping my knees and shoulders functional.

Let me know how this information sits with you. You may want to check out MFR information to see how others have found it helpful. Here is the link to that discussion.
https://connect.mayoclinic.org/discussion/myofascial-release-therapy-mfr-for-treating-compression-and-pain/
I will be waiting for your response.......especially your own suggestions.

May you be safe, protected and free of inner and outer harm.
Chris