This study demonstrated an additive effect of combining once-weekly parathyroid hormone with ongoing alendronate therapy on fracture healing in ovariectomized rats, even after long-term use of alendronate for anti-osteoporosis. This combined therapy resulted in improved mechanical strength of the fracture callus, driven largely by a significant increase in BV callus/TV callus and Tb.Th. These preliminary findings in an ovariectomized rodent model suggest that this combined treatment may benefit fracture healing in osteoporotic patients who used alendronate for long-term anti-osteoporosis therapy.