微孔涂层植人物与骨组织界面的生物力学关系

目的：探讨两种弹性模量不同的钛、钴合金微孔支植入物，对界面损伤的影响和裂纹扩展的规律，比较微孔涂层植入物在松质骨和皮质骨内的生物学固定界面的差异，方法：将标准钛、钴俣金材料的微孔涂层试件，分别植入犬股骨大粗隆左右侧，２４ＷＫ后取村，测定静态剪切强度极限和观察裂纹扩展规律。将标准的钛合金孔涂层试件植入犬股骨上段，试件上１／２端位于粗隆部的松质骨同内，下１／２位于股骨的皮质骨内。不同时间取村后，测定松

Biomechanical relationship between bone interface and porous coated implants

AIM: To investigate the effects of porous coatedtitanium alloy and porous coated cobalt alloy, which are of e-lastic modulus, on the bone interface injury as well as propa-gating rules of cracks, and to compare the biological fixationof porous coated implants in cancellus bones and corticalbones. METHODS: In the experiment, the two coated im-plants were implanted into the greater trochanter of the fe-mur (left, right) of the adult dogs for 24 weeks. Then theultimate strength of static shear was measured and the crackinitiation and propagation were observed- The porous coatedimplants were implanted into the proximal femoral canal-The proximal implants were closed by cancellus bone and thedistal implants were closed by cortical bone. After the im-plantation, the ultimate strength of static shear on the inter-face of biological fixation was measured in different time peri-ods. RESULTS: The u1timate strength of static shear ofporous coated titanium alloy implants was greater than thatof cobalt a1loy implants (P<0. 05), and under the interfaceof the static loads, the crack initiation, propagation andbreaking occurred later compared with cobalt al1oy implants.The u1timate strength of the static shear in cancellus boneand cortical bone showed significant difference (P<0. O1 ),which became greater with the passage of time after implan-tation. CONCLUSION: Because the elastic modulus ofporous coated implants is different, the ultimate strength ofstatic shear and crack initiation, propagation are different-When pro8theses with elastic modulus similar to that of bonytissues are hsed, the stress concentration of the interface wi1ldescend. The' ultimate strength of the static shear in cancel-lus bones is significantly greater than that in cortical bones.The biological fixation of porous coated implants needs lesstime in cancellus bones than in cortical bones and the fatiguelife increases with the passage of time after implantation.