Hi , Both of my legs were bowed due to my advanced osteoarthritis which is one of the reasons I did not wait any longer to have my knee replacements done 5 months ago. Both of my legs are straight now. It sounds like the cause of my osteoporosis in my left femur ( or technically called osteopenia at T score -2.1 ) could be the result of the bowed legs.
Did you have a bone scan on your left femur where you have your erosion? Did they prescribe osteoporosis meds for that?