Most importantly hit the exercises hard as you can from the beginning.
"I cant even hit a bucket anymore/ knee replacement"
Create and suffer pain in getting that knee to bend. I used my pyjamas, either top or bottom, as the strap to do the lying on your back, wrap it around foot and pull it toward you exercise. Pyjama top or bottom works the exercise sitting in a chair too.
The quicker you untangle the mess the op left the muscles, tendons/whatever et al around your new knew the better.
Gotta get it all stretched back to how it was. Suffer the pain early to make it better later.
Works out fine in most all cases, but a guy in hospital told me a friend of his didn't push hard on the basic exercises and was still suffering some pain a year after his op.
I didn't have any pain at all, except when still doing the flex exercise, after about three months.
Doc said on first visit back to him, "You have done all the hard work. Cruise now with the exercises. Do a lot of walking."
Riding a bike is a good one, i didn't get to it.
It was Plato who said, “He, O men, is the wisest, who like Socrates, knows that his wisdom is in truth worth nothing”
