Boy, when you exercise, you don't mess around, do you! Once your knee is all better, start with some light stretches. There are some in Fibro 101. Then start walking. Honestly, that will help kick in the metabolism. It did for me. That and counting carbs helped me lose 85 pounds.
Check out the walking in place videos by Leslie Sansone. (There are videos by others out there too but I'm familiar with this video.) The one I use is the 1,2,3 Mile Super Fat Burner...or something like that. Exercising 15 minutes by walking in place and moving your arms is equivilent to 1 mile of walking. You can do it for 45 minutes if you want to be equivilent to 3 miles but I never did that. I HATE to exercise. Fifteen minutes was it for me. But, I usually walked around the neighborhood instead of using the video. It comes in handy when you can't get outside.
You rest up that knee and feel better soon. You'll make it!
Sherrine