Walking, The ONLY thing I could do for quite some time post-surgery. I started by walking real short distances 3 times a day. Each day picked up the distance. After being healthy and active for my entire life, it was an eye opener to have trouble with even making it up a moderate hill!!!!
My dog would just look at me and wonder what was going on? (I was an avid runner)
Walking kept me sane, no doubt. Little by little I felt better and better.
I am back to running etc now, but I know walking is a better exercise overall.
I went through some fitness training recently (CrossFit). One of the big things the instructor impressed on me was that your body will get use to doing the same thing every day, and that increasing speed, or just changing up the routine is better for you. IE walking shorter distance faster, intervals, walking backwards, sideways, hills..... any kind of variances.