Here's the rest of my medical history, because it is relevant to the discussion.
I am an ex-professional horsewoman. In my twenties and thirties I rode 5 - 10 horses a day, for brief periods when I was working with TBs bound for the track, it was 10 - 14. I had a career ending injury when I was 39; I shattered my right ankle so badly it took 5 surgeries, including 2 bone grafts, pins and screws and a lot of rehab to put it back together again. I spent a lot of time on crutches and in a wheelchair and I believe that contributed to the accelerated degeneration of my left knee.
After that, I rode on the average amateur's or pleasure rider's schedule. Late forties, my knees started to bother me a LOT. I went through the entire gamut of non-prescription and prescription NSAIDs. I had fluid drawn off the left knee several times. I had cortisone shots every 3 months for 4 - 5 years (had them on a less agressive schedule in the right knee and right ankle as well) tried the hyluranic acid injections, and had two surgeries previous to the TKR - a standard arthroscopy and clean up of the meniscus and a lateral release - cutting the lateral patellar tendons on one side to allow the knee cap to track differently. During this period, I frequently walked with a pronounced limp and sometimes had to use a cane. I started taking non-narcotic prescription painkillers, with narcotic ones for break through pain. In order to ride, I iced before and after and doubled up on meds.
After all of that, my doctor finally agreed to TKR at 51. I had to go off the presciption NSAIDs and pain meds beforehand, and could barely walk well enough to walk into pre-op on my own.
So I loved my TKR. They gave me a spinal block to perform the surgery, and I woke up after surgery in less pain than I had been in *years*. The pain relief from the spinal block carried over for the first few days of PT, a huge advantage.
One year out, my functional level is much, much higher, but I still take the NSAIDs and pain meds for my right knee. I still sleep with a pillow between my knees. The only limitation on my left knee is that I can't kneel directly on the prothesis. Also, if I overdo it, the left knee swells dramatically.
To sum up? If I could control the pain with OTC meds, and I was relatively functional, I'd wait for the surgery. Even thought my result was incredibly positive, I'm in no hurry to do the right knee. I will manage my right knee with cortisone injections and oral meds for as long as possible before considering the second TKR.
BUT the big good news is that you absolutely can ride, and ride well, after TKR.