Osteomalacia is a pathological bone condition consisting in a deficient primary mineralization of the matrix, leading to an accumulation of osteoid tissue and reduced bone mechanical strength. The amounts, properties and organization of bone constituents at tissue level, are known to influence its mechanical properties. It is then important to investigate the relationship between mechanical behavior and tissue composition at this scale in order to provide a better understanding of bone fragility mechanisms associates with this pathology.

Our purpose was to analyze the links between ultra-structural properties and the mechanical behavior of this pathological bone tissue (osteomalacia) at tissue level (mineral and osteoid separately, or global). Four bone biopsies were taken from patients with osteomalacia, and subsequently embedded, sectioned, and polished. Then nanoindentation tests were performed to determine local elastic modulus E, contact hardness Hc and true hardness H for both mineralized and organic bone phases and for the global bone. The creep of the bone was also studied using a special indentation procedure in order to assess visco-elasto-plastic (creep) bone behavior. This allowed a detailed study of the rheological models adapted to the bone and to calculate the parameters associated to a Burgers model. Ultra-structural parameters were measured by Fourier Transform InfraRed Microspectroscopy (FTIRM) on the same position as the indents.

The use of rheological models confirmed a significant contribution from the organic phase on the viscous character of bone tissue. The elastic E and the elasto-plastic H_c deformation were correlated to both collagen maturity and Mineral/Matrix. The pure plastic deformation H was only correlated to the mineral phase. Our data show that mineral phase greatly affects mechanical variables (moduli and viscosities) and that organic phase (as illustrated in osteoid tissue) may play an important role in the creep behavior of bone. In conclusion, this study brings mechanical and physicochemical values for osteoid and mineral phases.

骨软化症是一种病理性骨病，其特征在于基质的主要矿化不足，导致类骨组织的积累和骨机械强度降低。已知在组织水平上骨成分的数量，性质和组织会影响其机械性质。然后，重要的是要研究这种程度的机械行为与组织组成之间的关系，以便更好地了解与这种病理学相关的骨脆性机制。

我们的目的是在组织水平（分别为矿物和类骨质或整体）上分析这种病理性骨组织（骨软化症）的超微结构特性与机械行为之间的联系。从骨软化症患者中取出四份骨活检，然后进行包埋，切片和抛光。然后进行纳米压痕测试，以确定矿化和有机骨相以及整体骨的局部弹性模量E，接触硬度Hc和真实硬度H。还使用特殊的压痕程序研究了骨的蠕变，以评估粘弹塑性（蠕变）的骨行为。这允许对适用于骨骼的流变模型进行详细研究，并计算与Burgers模型相关的参数。

流变模型的使用证实了有机相对骨组织粘性特征的重要贡献。弹性E和弹塑性H _c变形与胶原蛋白成熟度和矿物质/基质有关。纯塑性变形H仅与矿物相相关。我们的数据表明，矿物相极大地影响机械变量（模量和粘度），而有机相（如类骨组织所示）可能在骨骼的蠕变行为中起重要作用。总之，这项研究为类骨质和矿物相带来了机械和物理化学值。