Orthopedic bone plates are most commonly used for bone fracture fixation for more than 100 years. The bone plate design had evolved over time overcoming many challenges such as insufficient strength and excessive plate–bone contact affecting the blood circulation. However, it is only made of two materials, either stainless steel (AISI 316L) or titanium (Ti–6Al–4V). There are two main limitations of metallic bone implants, namely stress shielding and the problem of malocclusion caused by the displacement of the fracture site during healing. To overcome the two problems, a new bone plate design with the incorporation of auxetic structures is proposed in this work. This study aims to use auxetic structure section in the bone plate that would decrease the stiffness of the region, thereby mitigating the stress-shielding effect and at the same time act as a deformable section to enable intra-operative bending for effective alignment while having enough bending strength and stiffness. Two different auxetic structures namely re-entrant honeycomb and missing rib structures were considered. The auxetic structure incorporated bone plates were designed, finite element analysis was done, fabricated using direct metal laser sintering technique, and tested. The results indicate that the re-entrant honeycomb structure incorporated bone plates serve as an effective bone design compared to the conventional bone plate design, in terms of stress shielding and intra-operative bending while offering similar mechanical and bending strength.

中文翻译：

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一种3D打印的具有膨胀结构的矫形骨板的新设计，可减轻应力屏蔽并改善术中弯曲

骨科骨板最常用于骨折固定100多年。随着时间的推移，骨板的设计已经发展起来，克服了许多挑战，例如强度不足以及板骨接触过多，影响血液循环。但是，它仅由两种材料制成，即不锈钢（AISI 316L）或钛（Ti-6Al-4V）。金属骨植入物有两个主要局限性，即应力屏蔽和由愈合过程中骨折部位的移位引起的错牙合问题。为了克服这两个问题，在这项工作中提出了一种新的骨板设计，该设计结合了肿胀结构。这项研究旨在利用骨板中的肿胀结构截面来降低该区域的硬度，从而减轻了应力屏蔽效果，同时还充当了可变形部分，可在有效弯曲的同时进行术中弯曲，同时具有足够的弯曲强度和刚度。考虑了两种不同的膨胀结构，即凹状蜂窝和缺失的肋骨结构。设计并结合了骨板的膨胀结构，进行了有限元分析，使用直接金属激光烧结技术进行了制造和测试。结果表明，与传统的骨板设计相比，结合有骨板的凹入蜂窝结构可作为有效的骨设计，在应力屏蔽和术中弯曲方面，同时提供相似的机械强度和弯曲强度。