Ruthie, first let me say that I'm so happy that you made it through your surgeries and are healing well.
Second, as a dancer who knits, I like thigh high leg warmers myself with a fabric that is breatheable, cotton or cotton blend is good. You could use a wool blend, too, depending on the climate but I live in Savannah. I found several thigh high leg warmer patterns from Lion Brand and they have child sizes, too. I got this one by typing in "thigh high" but some show up under "leg warmers", too. Don't use all acrylic yarn--it is suffocating for dance class.
Here is one that uses sock yarn but Lion has them in worsted, too.
You need to sign up but all the patterns are free.
If you are looking at knee high, ChicKnits has one that is free also:
There are also tons of leg warmer patterns listed here:
If you are on Ravelry, there are tons of patterns there, too. Some are free and some are not:
But Lion has the only thigh high pattern i could find.