Local and Systemic Factors in the Pathogenesis of Osteoporosis

OSTEOPOROSIS is defined as a decrease in bone mass and strength leading to an increase in fractures, particularly of the vertebral bodies, proximal femur, and distal radius. According to this definition, the disorder must exist before the fracture occurs, but at present we cannot reliably diagnose osteoporosis before a fracture. Moreover, most hip and wrist fractures occur after a fall, and if there is no trauma the osteoporosis may never become clinically apparent. Even in vertebral crush fractures, which usually occur with little or no trauma, the defect in bone mass and strength may exist for years before fracture occurs. . . .