LAUSR

Bone matrix exhibits great complexity in its composition, structure and mechanics. Here, we provide a review of recent research articles and appraise the evidence that bone matrix quality is clinically important and possibly targetable for fracture prevention. Deformation of mineralised collagen fibrils determines bone fracture mechanics. Slipping and separation at the mineral-fibril and fibril-fibril interfaces, respectively, are the structural mechanisms for plastic deformation and microcrack nucleation. Existing technologies for assessing bone tissue in vivo cannot measure matrix structure or fracture mechanics but have shown limited use in clinical settings for identifying fragility or following treatment outcomes based on composition. Matrix is biomechanically and clinically important, but the knowledge has not translated into clinical practice. The structural mechanisms by which a load is transferred from mineralised collagen fibrils to the whole bone via microcracking have been proven too complex to measure in vivo. The mineral-fibril or fibril-fibril interfaces might be suitable targets for diagnosing fragility or delivering molecules that reduce fracture risk by strengthening the mineral bonds while maintaining flexibility in the fibrils.