Comparison of nanoindentation measurements between osteogenesis imperfecta Type III and Type IV and between different anatomic locations (femur/tibia versus iliac crest).

Nanoindentation was used to compare the intrinsic mechanical properties of bone tissue (iliac crest biopsy) from children with type III and type IV osteogenesis imperfecta (OI). Young's modulus and hardness values were not significantly different between the two clinical severity groups on either cortical or trabecular measurement. In comparing the ratio of modulus over hardness (E/H) between OI type III and IV. The type III bone showed a marginally significant decrease for cortical bone and significant decrease for trabecular bone, which indicated that the OI type III bone was more brittle than OI type IV bone at the tissue level. In addition, nanoindentation measurements of the bone tissue harvested at femur/tibia from the same patients were compared with the results from the iliac crest biopsy. Young's modulus and hardness values were not significantly different between the two anatomic locations in either cortical or trabecular measurements. The ratio of E/H was not significantly different between the two groups. Results indicate that intrinsic modulus, hardness, and indentation deformation pattern (E/H) of OI bone tissues are not significantly different at long bone (midshaft of femur/tibia) and iliac crest. We observed that age (1.9 to 13.2 years) did not influence OI bone tissue intrinsic mechanical properties.