I will echo the usefulness of physical therapy. Show the therapists that you are willing to work very hard, and they will work extra hard with you. You can gain strength and fitness in your 70's and beyond. Each day try to discover what you can do and do not dwell on what you can't do. Be patient, but do ALL that you can. Exercise the muscles that will bear it, let the others heal. Make sure your diet is very healthy to encourage your body to heal itself quickly.