It can take a full year for a TKA to fully heal and just as long for the swelling to go down. As long as you can fully straighten your knee and get at least 90 degrees Physicians (everywhere) consider that a great outcome. You really have to do the work. Stretching, heel slides with a sheet, having somebody push that knee back for you when you hit your own plateau. Hold that stretch for up to 10 minutes and do sets of 5 up to 3 times per day. Roll on an exercise ball. Sit on a porch swing and slowly keep bending your knee and increase your time. Google exercises. There are 2 PT guys that do YouTube videos showing advanced stretching. Are people going to the gym and riding a bike? Forward/back increasing and holding the stretch until a full revolution forward or backward can be done. Lower the seat, move the seat forward to increase the stretch. Stretch the hamstrings, soleus and gastronomic muscles (these all prevent a full ROM if they are tight). I think doing a MUA within that first 3-mths is extreme unless there is a medical condition that warrants it. Nobody knows scar tissue is solely the problem. We all get it after surgery and injury. You can loosen it on one part and have it sticking on another. It comes loose in pieces and sometimes not all of it ever loosens. Just keep doing aggressive therapy on your own and you'll get there.