First off, my deep sympathy to you over your knee problems! I always feel SO bad about anyone who injures a knee!
I had ACL surgery about 5 years ago.
I had originally injured my knee in 1993. I jumped off a wall and landed bad (I could feel the bones in my knee moving in ways that bones Are Not Supposed To Move.) I went to a doc-in-the-box and had it x-rayed, nothing broken. Walked with a cane for a few weeks, and took about a year before I could bend it completely (for example., while squatting), but it finally got so it felt pretty normal. (I theorized after the fact that I had maybe partially torn my ACL, or did some other cartilege damage at this time, but It Got Better By Itself.)
Then, at flyball practice with my dog one night, another dog got loose and ran in front of me. As I tripped over the dog, I felt the bones in my knee do the same thing they’d done when I’d jumped off the wall. I tried the same routine as before, but this time it didn’t get better. I’d sit in my chair at work and cry from the pain in my leg. And my knee was very unstable. Even when swimming (kicking while in the water), I could feel the bones in my knee slipping in bad ways.
I finally broke down and went to the doctor, got properly diagonsed, and decided to have the surgery. I had an auto-graft (they used the middle part of my patellar tendon to replace the ACL. I think these days they’re mostly using a bit of the hamstring as replacement tissue.)
I was non-weight-bearing (on crutches) for 6 weeks. I was out of work for 2 weeks, back on crutches after that. Luckily I have a sitting job. I did NOT have the passive-motion machine. I DID have the machine that circulates ice-water in a cuff that’s strapped around my knee – HIGHLY recommended!
I went through physical therapy for about 3 months, I think, going once or twice a week. The hardest part for me was getting back flexion (being able to bend the knee.) FOR ME, physical therapy was the most excruciating thing I have ever endured. I was SO HAPPY the first day I went through a whole session without crying in pain most of the hour. But you REALLY have to do it anyway.
Keep in mind I was about 45 when I had the surgery. I think the time he kept me on crutches was a VERY conservative treatment based on my age and condition. I was not very fit at the time. I believe that many people who are more fit and athletic get through the surgery and rehab more easily that if you’re not-so-fit.
I got a LOT of information and advice (and encouragement) from the folks on Bob’s WWW ACL board (http://factotem.org/cgi-bin/kneebbs.pl). You can read stuff here from folks who had the surgery and were back riding bikes and exercising in about a month.
I DON’T regret having the surgery. My knee is more stable now, and my pain is less. (Pain is not completely gone, but I’m 50 now, and I’m sure I have arthritis to deal with as well. I’ve also got some weird structural issue in my left leg, because my hip joint has hurt almost as much as my knee since I injured it the second time.) But that’s me. Most folks do NOT have this problem.
It was all much harder than I had thought it would be. But it was still the right thing to do. And now I know that I can deal with this kind of hard thing, which is useful in its own right.
Very good luck, and very best wishes!!!