You will never heal any faster than the current time simply due to age progression.
Before I had my TKR at 59 I was doing 2/3 of Triathlon---i.e., Aquabike. Now I do the whole nine yards, but I walk (though I can short of run/shuffle if I want to, which I don't). I wish I had done mine earlier.
FWIW, my ortho doc rates TKR success at about 90+%, much better than many other knee procedures.
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