Oh, and, Dorothy, I'm glad you brought up Glucosamine (and MSM).

I know at least one MD (with a background in kinesiology and knowledge of holistic medicine too) who says that Glucosamine has been shown to help rebuild cartilege sometimes.   She says there's not much evidence that Chondroitin can and that MSM is mainly for pain relief (which can also be important).   What I have decided to do -- and hope it's not too late -- is to undertake a serious program of getting a lot of calcium and vitamin D plus glucosamine, plus exercises and phys. therapy -- with emphasis on frequent short walking and exercise sessions, slow stretching of the legs, back, etc., and on exercises that will build up the quads, glutes, and calf muscles.    This plus getting the kind of mattress that will allow the right kind of rest and sleep.   (I may even invest in a back swing or slant board so that I can use my inversion boots again and stretch out the lower vertebrae.   When I used to do this sort of thing back in the '80s and '90s, it really made my back feel better.)   
As I said above, if I'm going to have to undergo a serious physical therapy regimen, why not try it out BEFORE having the hip replacement? At least then, if I have to have the surgery, my muscles and bones should be in better shape to deal with the surgery and its aftermath.