Bones may seem like such solid, unchanging objects. In reality, they're very dynamic. New bone tissue is constantly being laid down while old bone is being removed. This works something like the deposits and withdrawals in a bank account. The system usually works well. This changes as people get older. Withdrawals exceed deposits; bones become less dense and more fragile. They fracture more easily and when they do, fractures heal much more slowly and poorly. This weakening of the bones is known as osteoporosis. The problem is most severe in post-menopausal women. The lack of estrogen tilts the balance in favor of withdrawals from the bone account.
This effect was strongest at the hip, where denosumab increased bone density over thirty-three percent more than alendronate did.