Measuring fracture toughness of mouse bone

Bone is a composite material that develops its mechanical properties from its complex hierarchical structure composed principally by type I collagen and a mineral, hydroxyapatite. Bone fracture toughness is currently the most accurate measure of bone fragility, thus representing a critical bone quality property to assess bone resistance to fracture in aging and disease bone, and for the development of effective clinical treatments. This study focuses firstly on the assessment of the effect of ketamine treatment on healthy and brittle bone with osteogenesis imperfecta (OI). The quantitative assessment of bone fracture toughness is performed exploiting the linear elastic fracture mechanics stress intensity factor, 𝐾𝑐, method on bones notched on the posterior side. Secondly, the study focuses on the assessment of the effect of bone heterogeneity on fracture toughness, thus fracture toughness of bone notched in medial side were compared to those of bone notched in the posterior side. Our results show that ketamine administration does not improve bone fragility in OI bones, but rather makes healthy bones more fragile. Furthermore, there is no difference between healthy bone fracture toughness calculated with the notch on the posterior or medial side. What we show here add new insight on the effect of treatments and anatomical characteristics on bone fracture toughness and fragility, paving the way for new studies to be conducted.