I'm now 19 weeks post-op and thought I would give a short update. The new knee seems to be settling in now, and the various muscles and ligaments are also finding life easier. The latest strain appears to be healing.
There is still some residual stiffness, especially after sitting for long periods (more than 2 hours) at work. Unforced ROM is an easy 0 to 125. The knee will bend quite a bit further with assistance, but the additional bend is painful and neither my physiotherapist nor I think this is a good idea. We're waiting for the joint to be able to do it under its own steam, without pain, which I think will be achieved over time.
I still have occasional pain in the joint, usually after lots of exercise, but it doesn't generally get much above a 2 or 3 on the scale, which is light-years better than the constant 8 or 9 I was having before the operation. I'm off all painkillers completely, but will sometimes take Tylenol for the sake of comfort (usually after agility trials, when I've overdone things). I still elevate the leg in the evening, and use ice after exercise.
The leg is gradually becoming stronger, and while I don't think I could handle a hike in the mountains just yet, I'm hopeful that I can do so by the fall. However, on reasonably flat terrain I can walk for several miles with no problem. I can mow our lawn (it takes an hour with a heavy electric mower) and do all the yardwork. The dog training activities, which involve running, changing direction and so forth, are getting easier, but there's still much to be achieved here. I'm not pushing things too much because I don't want to have any more pulled muscles or strained tendons, and I don't want to twist the joint either. I'm confident that I can get to where I want to be, in terms of speed, over time.
I also think about the knee much less in everyday activities. The other day I ran downstairs (using the handrail for support) without realizing what I was doing until I was at the bottom. We're planning a family vacation in August that will involve lots of walking and a day of wild bird photography for me - I haven't been able to do that for a long time, because of the need to crouch and sit on the ground. I'm looking forward to it.
I'm keeping my fingers crossed that things continue to go well.
I do wish I'd had the TKR sooner. I put it off for at least a couple of years because I have an innate fear of hospitals, but in the end it has given me my life back. As for the hospital, I was able to do the operation on an outpatient basis (no overnight stay), so it was much less stressful.
United States
And your dog is amazing. I can’t tell who loves doing this course more, you or your beautiful dog.
Sitting for long periods was one of the last things to become pain-free for me. Before having this surgery I would have thought sitting was a no-brainer (no-painer?) but I sure learned otherwise! Like you, I sit for long periods. I'm a writer. Fortunately, after about 10 months for me, the pain and then the stiffness after sitting for long periods finally went away. 
