应力遮挡对延长骨力学性能的影响

Effect of stress shielding on the mechanical nature of lengthened bone

通过２８只幼龄绵羊胫骨上干骺端截骨延长肢体动物实验，采用组织学及生物力学等方法，着重探讨外固定器的应力遮挡作用对延长骨力学性能的影响。结果表明，外固定器进行骨延长，其应力遮挡作用在骨延长期间和延长结束后早期，能够保持骨断端的牢固稳定，有利于骨的再生与修复，但如果固定时间过长，将会影响骨的正常改建，导致两端皮质骨的骨量丧失，从而引起延长骨抗弯强度的下降。

Limb Lengthening experiments were carried out at the level of upper tibia of 28juvenile sheeps by performance of metaphyseal osteotomy. Using histogical and biochemicalmethods, We emphatically explored and discussed the stress shielding effect of external fixatoron the mechanical nature of the lengthened bones. The results showed that the external fixatorcan maintain the stability and immobilization of the segments in the lengthening period and in theearly stages at the end of lengthening. These effects are beneficial to the regeneration and repairofthe bone tissur. However,if the fixation time goes too long, it will surely affect the normal re-modIing of the bone loss of the cortex,as well as a decrease in the anti一bending strength of thelengthened bone.