I am now about 7 months post-op from my microfracture. I had two good sized lesions in my right knee. This was my second surgery. The first was just to clean it out.
I was having a very hard time riding for the first part of last year. Lots of pain an swelling. I also couldn't walk very well. I tried physical therapy, getting fit on the bike, the Shimano heat molded shoes and everythign else my doctor said. We finally did the MRI and found the cartilage problems.
The loose pieces were contributing to the swelling, but the bone on bone was a source for a lot of the pain. My body was reacting to the problems which caused the other conditions.
Anyway, it is a long process, and I am not done yet. I am still primarily on the trainer, but I am going to start riding outside soon. If I get good results, I think I will be getting myself a new ride with a compact crank set.
There are a lot of sites out there where you can learn about Microfracture. google for "microfracture woo hoo". I also created a blog of my diagnoses and experience. http://www.podilato.com/category/microfracture/
If your lesions are in a weight bearing spot, you need to keep all of your weight off it. That means crutches for 6-8 weeks. Don't skimp on it. That means you will loose all of your muscle which will take a long time to build back up.
The basic theory behind the procedure is that for small lesions (less than 3cm), you can naturally repair them. Basically, cartilage doesn't regrow. That said, the blood in your bone which has bone-marrow, will for a "scab" that is very similar to the good cartilage you should have. It is not the best, but it is yours and they are having good luck with it.
What they do is clean out the area so it is like a pot-hole in the street. Clean to the bone with steep walls. Then they drill holes in the bone deep enough to get blood out. The blood fills the pot hole. As the blood sets up and becomes a "scab" it actually forms cartilage. This is your patch.
This "patch" takes time to set up properly. Then, it takes time to become hard enough to actually work. This is the hard part of the surgery; time. It is arthroscopic which is the best part. The rough time for recovery is 6 months. The other procedures are full open knee with 12 month recoveries.
So, I am 7 months post-op and doing very well. I am not pain free, but I am getting better. I do have much less pain than before the surgery.