Had my TKR in 2017 too. I have scar tissue and my mobility after a manipulation 2 or 3 months after the TKR was only at 65. I did feel numbness for a long time, probably at least for a year. The numbness eventually dissipated but I do still have scar tissue. I have most recently been applying pressure to my knee while using magnesium oil topically. I do this on my bus commute to and from work (which is about 100 miles each way) as well as when I am reclining at home before bed. I have also been sitting in a jetted tub with Epsom salts (magnesium) for about 12 to 15 minutes 1 or 2 times a week and sitting in a hot tub for 30 minute sessions, while flexing and bending my knees about twice a week. After the hot tub, I find my knees more flexible so push myself into squats. Initially this caused a lot of pain and discomfort but I am currently experiencing some minor improvement in terms of slightly less stiffness in the TKR knee and miniscule improvement in mobility (putting on socks and shoes). For the last several days I have been taking one 500 mg Bayer aspirin daily so have not really felt any pain in either knee (I also massage both knees), and the left knee is bone-on-bone. The movement of warm/hot water around the knee joint seems to facilitate being more flexible but you can ask your doctor. My surgeon said the rehab facility where I was for about 15 days did not do the aggressive therapy, so go figure. I have decided no more surgery for me and I stopped physical therapy some time ago. If you can do water aerobics and swim, they are also helpful.