Machining-induced thermal damage in cortical bone: Necrosis and micro-mechanical integrity
Machining-induced thermal damage in cortical bone: Necrosis and micro-mechanical integrity
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DOI：
10.1016/j.matdes.2020.109215
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发表时间：
2021
影响因子：
8.4
通讯作者：
Jose A. Robles-Linares;D. Axinte;Z. Liao;A. Gameros
中科院分区：
文献类型：
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作者：
Jose A. Robles-Linares;D. Axinte;Z. Liao;A. Gameros
在骨切割中，组织由于温度升高而暴露于坏死，这会显著影响骨科手术的术后结果。这种损伤通常通过组织学分析显示，以显示坏死程度;然而，这种技术不能捕获机械损伤，这对于完整的材料完整性评估至关重要。在这里，与微观力学，它表明，机械加工引起的骨损伤超出坏死区域。对离体牛皮质骨进行不同条件的钻孔，造成不同程度的损伤。微柱压缩试验进行了机加工的次表面，以确定性能的变化和破坏模式所造成的钻孔。结果表明，在高切削温度下，加工表面附近的骨具有较低的模量（-42%），强度（-41%）和脆性行为，而大块骨保持原始特性和韧性行为。还进行了组织学检查以评价坏死，令人惊讶的是，发现与坏死层相比，脆性和较弱的骨层大三倍以上，清楚地表明钻孔热机械效应不仅会影响生物学，而且还会影响微观机械。因此，这些结果揭示了另一种迄今为止被忽视的骨损伤。
In bone cutting, the tissue is exposed to necrosis due to temperature elevation, which can significantly influence postoperative results in orthopaedic surgeries. This damage is usually revealed through histological analysis to show the necrotic extent; however, this technique does not capture mechanical damage, which is essential for a full material integrity assessment. Here, with micro-mechanics, it is demonstrated that machining-induced damage in bone extends beyond the necrotic region. Drilling with different conditions was performed on ex-vivo bovine cortical bone, inducing different damage degrees. Micro-pillar compression tests were performed in the machined sub-surface to identify changes in properties and failure modes caused by drilling. It was revealed that at high cutting temperatures, the bone near the machined surface suffers from lower modulus (−42%), strength (−41%) and brittle behaviour, whereas the bulk bone remains undamaged with pristine properties and ductile behaviour. Histology was also performed to evaluate necrosis and, surprisingly, it was found that the brittle and weaker bone layer is more than three times larger when compared to the necrotic layer, clearly showing that the drilling thermo-mechanical effect could affect not only biologically, but also micro-mechanically. Consequently, these results reveal another kind of bone damage that has so far been neglected.