A biomechanical perspective on bone quality

Observations that dual-energy X-ray absorptiometry (DXA) measures of areal bone mineral density cannot completely explain fracture incidence after anti-resorptive treatment have led to renewed interest in bone quality. Bone quality is a vague term but generally refers to the effects of skeletal factors that contribute to bone strength but are not accounted for by measures of bone mass. Because a clinical fracture is ultimately a mechanical event, it follows then that any clinically relevant modification of bone quality must change bone biomechanical performance relative to bone mass. In this perspective, we discuss a framework for assessing the clinically relevant effects of bone quality based on two general concepts: (1) the biomechanical effects of bone quality can be quantified from analysis of the relationship between bone mechanical performance and bone density; and (2) because of its hierarchical nature, biomechanical testing of bone at different physical scales (