Hi Mate,
With regards to having a total knee replacement, I had mine done 6 years ago when i was 59 years young.!!
The operation was a success, i had the epidural in the back so was awake the whole time.
After spending the night in hopspital i was allowed home after completing certain tasks.
The one bit of advice i can offer is work hard at the excercise regime they give you,
myself after five days i put my mountain bike on a turbo trainer and did some gentle cycling for about
5 mins a day. by the time i went back to see the surgeon i was walking ok without the help of a walking stick
the surgeon couldnt believe what he saw and asked what i did.
Good luck with the Operation