Can't talk about knee replacement, but I have a lot of experience with hips. I had my left hip replaced in 1996 and went back to work in 4 weeks. Would have been faster, but I got a urinary tract infection that slowed me down.
Had to have that hip redone in 2003-4 because it turned out that I was allergic to the bone cement used in '96. It ate into the pelvis as well as having to split the femur to remove all of it. I was without a hip for about 9 months due to other problems. Had the redaction done at Stanford and was up and about in a couple of months. Main reason for being slow was no hip, which caused me to have to start walking over again.
Had my right hip done in 2006 and was up and out in 3 weeks again.
since that time, I have had no issues with either hips and do very well.
I did go out in my MH while I was sans left hip. Used crutches and did pretty well.
Overall, I highly recommend repairing the hip because the pain you have now willo be a thing of the past. Most people say "Why did I wait so long!"
Get it done as soon as you are able.