How effective is Fosamax? In one year, for example, how much bone density will I recover?

The use of Alendronate (e.g. Fosamax) causes a shift of bone balance toward bone formation by inhibiting bone resorption and has been shown to increase bone mass.
Two studies about Alendronate include
1.Lieberman et al — 10 mgs of Alendronate per day over a three-year period of time built bone mass in 96% of patients and decreased the risk of fracture significantly.
2.Fracture Interventional Trial by Black et al — with the use of Alendronate, there was a 47% decrease in new vertebral fractures, a 50% decrease in hip fractures, a 55% decrease in the risk of symptomatic vertebral fractures, a 48% decrease in wrist fractures, and a 28% decrease in the risk of all clinical fractures.