good luck rudey.
dont worry you will be fine. i had 2 knee ops on my left knee and had morphine for the second one as it was open knee surgery. but i recovered as will you.
a colleague at work just had a op on his 2 knees and they put staples in

but in a few months he is now walking around as if nothing ever went wrong.
So chin up fella.
Oh and fook blazing u wanna make sure u get the morphine

i had it on a drip and was pressing the button every 5 mins

and the od'd in the morning and puked everywhere