There have been numerous threads on reel mowers, so you might read through those first. The search engine works well.

If you have a broken back and a bad knee I would think that pushing a reel mower would not be a good idea. With a broken back you should laying flat I would think.....

Thanks for your suggestion, but I did not find one with current recommendations and there is a new product every day. Meanwhile, I still have a garden - 30 x 10 and 1 1/2 acre to mow. I absolutely love gardening and want to be able to continue for a long time! I do not let those disabilities hold me back but as you can tell, I try to take care of myself by eating fresh foods and being active!

What kind of grass are you cutting? Most reel mowers are designed to cut at 2" or less. I have a Brill, which is very light and never requires sharpening, but the max height is 1.8"
http://www.peoplepoweredmachines.com/products/brill_luxus33.htm

Cool season grasses (and SA) do better when cut 3" or higher.