When my cham had MBD (a pretty severe case...) we did the following:
oral calcium (calciumgluconate or however it's spelled) daily.
Vitamin D3 injections weekly (you can easily do this at home once shown how)
after a few weeks to boost his calcium levels we added in calcitonin injections (prevents his bones from having MORE calcium leached from them during tx ... can't do this right away though because imp. organs like their hearts NEED calcium).
Casted his broken legs. These were changed every 2 weeks.
It took months of intensive care (he had to be put on "bed rest" so that he couldn't continue to climb and fall, break more bones, fall more etc. )
After about 3 months his legs healed and 6-9 months the bone density in his legs returned to normal.
Although bloodwork and xrays are not NEEDED to dx MBD in a case like yours (it's pretty obvious that leg is broken and he will probably always have the "double elbow" bc it will probably heal crooked) they can be helpful. One -- blood work allows you to look at his ca

hos levels to see where they are and how bad they are. It allows you to look at organ function to see if he has any other problems (and if you have good husbandry this would be suspect ... they shouldn't develop MBD for no reason). An xray allows you to check his spine and head integrity bone structure wise -- my cham had NO bone density in his extremeties (they looked like cartilage) but great spine/head density which gave us hope. It will also, if you have enough bone density to SEE his bones allow you to find more fractures and act appropriately.
Just my experiences.