I've backpacked w/ a 60 lb pack, and it was HARD! But that was about what I lost too, so I see the concept, and how it would work.
that said, there are lots of ways to lighten your pack, and I would really recommend that if you decide to try backpacking. Especially if you don't have the equipment yet, it would be good to go somewhere (like REI) where they can measure you, fit you, and advise you on packs that will work for what you want to do, and let you know the best way to load it up for weight distribution. that will really help avoid back, shoulder and neck issues. I think this would be especially important w/ your hip issue, as most packs rest on the hip so that is where you are carrying most of the weight (it keeps the strain off your neck and shoulders...)
highest weight ever:202, SP starting weight: 143
New goal: 125 lbs, just to see what that looks and feels like! Hit it: Feb 2013!
H: 5''4" 49 y.o.
"Don''t let yesterday use up too much of today." Will Rogers
"Eat Food, Not Too Much, Mostly Plants" Michael Pollan
| current weight: 10.4 over