Your mother is a victim of rebound fracture of Prolia. By googling I found that Prolia is less effective than bisphosphonates for reducing fractures and increases infection risk. Now Aclasta contains zolendronic acid (sometimes called zolendronate) and it belongs to bisphosphonates group. I think it is more effective than Prolia. Remember to check urea, creatinine before Aclasta injection and also take 1-2 glasses of plain water 1(one) hour before injection.

My mother Sobha Ghoshal has taken Bonmax Pth (teriparatide) injection for 2 years for Osteoporosis. But it failed to increase the bone density in the hips and so the risk of hip fracture is still there after completion of 2 years course. The T-score in the femur neck right as well as left in the hips did not improve at all from the first BMD Test done on 19.09.2018 although there is drastic improvement of bone density in AP Spine. Please see the chart below.

BMD TEST done on 19.09.2015
BMD Test Done on 18.09.2017
  Region
T-Score
Region
T-Score
Femur Neck Left
-2.2
Femur Neck Left
-2.2
Femur Neck Right
-2.1
Femur Left Right
-1.8
AP Spine L1-L4 is 1.007  g/cm2
-2.2
AP Spine L1-L4 is 0.920  g/cm2
-1.4

Did you ask your mother's doctor that prolia induces rebound fracture and one will be addicted to it.