You might try exercising your upper body to some of the FREE videos offered on Spark's CHAIR EXERCISE TEAM's YOU TUBE channel, accessed by clicking on their Logo on their team home page. You will find hundreds of movement ideas that don't use your legs, as well as others that use legs without leaving your chair or bearing weight. These can help you maintain much of your hard earned fitness level while you recouperate. You may also find these exercises helpful as you begin to put your new knee back into action, which as I recall, requires considerable work (my sis had her knees done). Everyone is welcome on this team, regardless of fitness level, permanent or temporary. God Bless your efforts!