ABSTRACT
Osteoporosis has been characterized as a disease of decreased bone mass. Bones were considered to fracture due to a reduction in their mass. Accordingly, osteoporosis has been diagnosed based on a surrogate for bone mass, the areal bone mineral density (BMD). Treatments have been developed to prevent bone loss or restore bone lost, and their efficacy measured by how well these outcomes are achieved. However, several observations from large clinical trials have exposed the limitations of BMD measurement. Many fractures occur among patients with normal BMD1, small changes in BMD result in greater than expected reductions in fracture risk2, reductions in fracture risk are evident before maximal changes in BMD are achieved3
and changes in BMD following antiresorptive treatment explain only a small proportion of the variance in fracture risk reduction4. The term bone quality has been used to explain these and other clinical findings that cannot be explained by BMD measurements. During the past decade, interest in bone quality has increased dramatically, but the use of the term has been inconsistent, mainly due to the lack of a consensus on an operational definition.
