Medical Device Research Institute, College of Science and Engineering, Flinders University, Adelaide, South Australia, Australia.
Medical Device Research Institute, College of Science and Engineering, Flinders University, Adelaide, South Australia, Australia; Flinders Microscopy and Microanalysis, College of Science and Engineering, Flinders University, Adelaide, South Australia, Australia.
J Mech Behav Biomed Mater. 2024 Mar;151:106347. doi: 10.1016/j.jmbbm.2023.106347. Epub 2023 Dec 28.
Primary stability, the mechanical fixation between implant and bone prior to osseointegration, is crucial for the long-term success of cementless tibial trays. However, little is known about the mechanical interplay between the implant and bone internally, as experimental studies quantifying internal strain are limited. This study employed digital volume correlation (DVC) to quantify the immediate post-implantation strain field of five cadaveric tibiae implanted with a commercially available cementless titanium tibial tray (Attune, DePuy Synthes). The tibiae were subjected to a five-step loading sequence (0-2.5 bodyweight, BW) replicating stair descent, with concomitant time-elapsed micro-CT imaging. With progressive loads, increased compression of trabecular bone was quantified, with the highest strains directly under the posterior region of the tibial tray implant, dissipating with increasing distance from the bone-implant interface. After load removal of the last load step (2.5BW), residual strains were observed in all of the five tibiae, with residual strains confined within 3.14 mm from the bone-implant interface. The residual strain is reflective of the observed initial migration of cementless tibial trays reported in clinical studies. The presence of strains above the yield strain of bone accepted in literature suggests that inelastic properties should be included within finite element models of the initial mechanical environment. This study provides a means to experimentally quantify the internal strain distribution of human tibia with cementless trays, increasing the understanding of the mechanical interaction between bone and implant.
初始稳定性，即在骨整合发生之前种植体与骨之间的机械固定，对于非骨水泥胫骨托的长期成功至关重要。然而，对于种植体与骨内部之间的机械相互作用知之甚少，因为定量内部应变的实验研究有限。本研究采用数字体相关（DVC）技术来量化 5 个尸体胫骨在植入市售非骨水泥钛胫骨托（Attune，DePuy Synthes）后的即刻植入后应变场。胫骨经历了一个五步加载序列（0-2.5 体重，BW），模拟楼梯下降，同时进行时变 micro-CT 成像。随着负荷的增加，骨小梁的压缩量增加，胫骨托植入物后部区域的应变最高，随着与骨-植入物界面距离的增加而消散。在最后一个加载步骤（2.5BW）的负荷去除后，在所有 5 个胫骨中都观察到残余应变，残余应变局限于距骨-植入物界面 3.14mm 以内。残余应变反映了临床研究中观察到的非骨水泥胫骨托初始迁移。在文献中接受的骨屈服应变以上的应变的存在表明，在初始机械环境的有限元模型中应包括非弹性特性。本研究提供了一种实验量化非骨水泥胫骨托中人类胫骨内部应变分布的方法，增加了对骨与植入物之间机械相互作用的理解。
