Exercises that don't involve the knee?

My sister has a torn pcl and meniscus and has developed OCD in her cartilage (all in her right knee) and she just had surgery for the meniscus and OCD and will be having another in a couple months for her pcl, so she won't be able to move her knee at all for about a year. If you know of any exercises that can help her remain fit that don't involve the use of one of her legs, that would be a great help!! Thank you and God bless:)