Pixie has had several surgeries for this. Her right leg was grade 4 & permanently dislocated. They fixed it in April. Recovery was about 8 weeks. I am pretty weak about those type things, and I wasn't sure I could handle it, but really, it wasn't so bad. Not at all.
Then a couple weeks ago, they did her left leg. At that time, they noticed that her pin in her right was coming out, so they opened it back up, too. They said they don't normally have to go back in and take the pin out or anything, but they felt it was necessary with her. She is doing remarkable now (about 2 weeks later).
She is still on limited movement, but she is getting around excellent. We have started physical therapy on both back legs - it's not so bad. We started with range of motion and massages until she could walk. Now she's able to walk, so we do massages and short walks. We will graduate on up to doing water therapy one of these days, but we need some more walks first
Going into it, I was scared, upset, confused, etc. You name it, that was me. I was really dreading having to take care of her and keep her confined. I had no idea how to handle her post-surgery, either. Now we've had 4 surgeries (including getting fixed), and the vet knows us so well and we've done such a good job, he doesn't do checkups. By now, he tells me, "You know what you're doing. Call if you have questions or if something doesn't look right."
In sum, the surgery really isn't that bad. Recovery isn't bad either. It's so good to see them learn to walk again on their leg and this time, not hurt.
If you opt to NOT do surgery, or if you choose to put it off, remember that any damage done is irreversible. Once the cartilage is damaged/gone, it doesn't come back. I highly suggest getting it fixed while you still can. We were very lucky with Pixie. Hers was grade 4 (right leg) and she couldn't walk on it at all. Often times once it gets so far, they can't do much.
Talk to your vet, research, talk to others, but if it's a grade 3, it needs surgery soon. Don't wait.