Hi Andrea, sorry to learn of your fractures. I empathize with you regarding the full leg plaster cast you are in. I'm in a plaster splint as I only broke my leg 5 days ago, its got a gap down one side to allow for swelling but its huge - goes from toes to my hip almost, uncomfortable beyond belief.
I posted on the discussion board today about also feeling claustrophobic in the splint so know how you are feeling. Its also incredibly difficult not being able to bend my knee, like you say.
I find out this week if I need an operation or if I'm going to just get another cast (I'm praying if I do it will end below my knee for obvious reasons).
I hope you soon start to get to grips with your situation and heal quickly,

Best wishes rob