A frequent cause of problems is Femara (or aromatase inhibitors generally) as these are known to reduce bone density, but if you haven't been taking these I am not sure what may be causing it. I had my bone density tested near the end of chemo (because I was going on Femara and to serve as a reference point) and it was excellent (which was good because it will take a bit of a beating!) and no osteo-arthritis so chemo didn't have any impact on me as far as I can tell. Good question though, be interesting to see if others have experienced the same effects.
