Mechanical effects on the skeleton: Are there clinical implications?
Mechanical effects on the skeleton: Are there clinical implications?
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DOI：
10.1007/s001980170161
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发表时间：
2001-01-01
影响因子：
4
通讯作者：
Forwood, MR
中科院分区：
文献类型：
--
作者：
Forwood, MR
骨骼的基本形态是由遗传决定的，但其最终的质量和结构是由对机械因素敏感的适应机制调节的。当承受载荷时，骨抵抗骨折的能力取决于其质量、材料特性、几何形状和组织质量。骨几何结构改变对骨折风险的贡献在临床评估中没有得到吸收测定法的重视，因为它不能区分几何结构和密度。例如，对于相同的骨面积和密度，骨干半径的小幅增加对骨的扭转强度产生不成比例的影响。力学因素具有临床相关性，因为它们能够影响生长、建模和重塑活动，这些活动可以最大限度地提高或维持抗骨折性的决定因素。机械负荷，大于那些经常遇到的骨骼，影响适应皮质骨和松质骨，降低骨转换率，并激活新骨形成的皮质和骨小梁表面。在这样做的过程中，它们通过组织的几何尺寸和材料特性的有益适应来增加骨强度。没有直接证据证明机械载荷的抗骨折功效，但所产生的几何变化无疑增加了骨作为器官的结构特性，增加了抗骨折性。与所有干预措施一样，安全问题也会出现。涉及高应变率、举重或冲击负荷的体力活动可能对关节有害，导致骨关节炎;可能刺激疲劳损伤，导致一些应力性骨折;或可能与药物干预相互作用，增加皮质骨或骨小梁内的微损伤率。
The basic morphology of the skeleton is determined genetically, but its final mass and architecture are modulated by adaptive mechanisms sensitive to mechanical factors. When subjected to loading, the ability of bones to resist fracture depends on their mass, material properties, geometry and tissue quality. The contribution of altered bone geometry to fracture risk is unappreciated by clinical assessment using absorptiometry because it fails to distinguish geometry and density. For example, for the same bone area and density, small increases in the diaphyseal radius effect a disproportionate influence on torsional strength of bone. Mechanical factors are clinically relevant because of their ability to influence growth, modeling and remodeling activities that can maximize, or maintain, the determinants of fracture resistance. Mechanical loads, greater than those habitually encountered by the skeleton, effect adaptations in cortical and cancellous bone, reduce the rate of bone turnover, and activate new bone formation on cortical and trabecular surfaces. In doing so, they increase bone strength by beneficial adaptations in the geometric dimensions and material properties of the tissue. There is no direct evidence to demonstrate anti-fracture efficacy for mechanical loading, but the geometric alterations engendered undoubtedly increase the structural properties of bone as an organ, increasing the resistance to fracture. Like all interventions, issues of safety also arise. Physical activities involving high strain rates, heavy lifting or impact loading may be detrimental to the joints, leading to osteoarthritis; may stimulate fatigue damage leading with some to stress fractures; or may interact pharmaceutical interventions to increase the rate of microdamage within cortical or trabecular bone.