Liu Bingchuan, Li Xingcai, Qiu Weipeng, Liu Zhongjun, Zhou Fang, Zheng Yufeng, Wen Peng, Tian Yun
Department of Orthopaedics, Peking University Third Hospital, Beijing, China.
Engineering Research Center of Bone and Joint Precision Medicine, Ministry of Education, Peking University Third Hospital, Beijing, China.
Front Bioeng Biotechnol. 2022 Jun 3;10:921545. doi: 10.3389/fbioe.2022.921545. eCollection 2022.
Critical metaphyseal bone defects caused by nonunion and osteomyelitis are intractable to repair in clinical practice owing to the rigorous demanding of structure and performance. Compared with traditional treatment methods, 3D printing of customized porous titanium alloy prostheses offer feasible and safe opportunities in repairing such bone defects. Yet, so far, no standard guidelines for optimal 3D printed prostheses design and fixation mode have been proposed to further promote prosthesis stability as well as ensure the continuous growth of new bone. In this study, we used a finite element analysis (FEA) to explore the biomechanical distribution and observed new bone regeneration in clinical practice after implanting 3D printed prostheses for repairing metaphyseal bone defects. The results reflected that different fixation modes could result in diverse prosthesis mechanical conductions. If an intramedullary (IM) nail was applied, the stress mainly conducted equally along the nail instead of bone and prosthesis structure. While the stress would transfer more to the lateral bone and prosthesis's body when the printed wing and screws are selected to accomplish fixation. All these fixation modes could guarantee the initial and long-term stability of the implanted prosthesis, but new bone regenerated with varying degrees under special biomechanical environments. The fixation mode of IM nail was more conducive to new bone regeneration and remodeling, which conformed to the Wolff's law. Nevertheless, when the prosthesis was fixed by screws alone, no dense new callus could be observed. This fixation mode was optional for defects extremely close to the articular surface. In conclusion, our innovative study could provide valuable references for the fixation mode selection of 3D printed prosthesis to repair metaphyseal bone defect.
由于结构和性能要求严格，临床实践中由骨不连和骨髓炎引起的关键干骺端骨缺损修复起来很棘手。与传统治疗方法相比，定制多孔钛合金假体的3D打印为修复此类骨缺损提供了可行且安全的机会。然而，到目前为止，尚未提出关于最佳3D打印假体设计和固定方式的标准指南，以进一步提高假体稳定性并确保新骨持续生长。在本研究中，我们使用有限元分析（FEA）来探索生物力学分布，并观察在植入3D打印假体修复干骺端骨缺损后的临床实践中的新骨再生情况。结果表明，不同的固定方式会导致假体机械传导不同。如果应用髓内（IM）钉，应力主要沿钉均匀传导，而不是通过骨骼和假体结构。而当选择打印翼和螺钉来完成固定时，应力会更多地转移到外侧骨骼和假体主体上。所有这些固定方式都可以保证植入假体的初始和长期稳定性，但在特殊生物力学环境下新骨再生程度不同。IM钉固定方式更有利于新骨再生和重塑，这符合沃尔夫定律。然而，当仅用螺钉固定假体时，未观察到致密的新骨痂。这种固定方式对于极其靠近关节面的缺损是可选的。总之，我们的创新性研究可为3D打印假体修复干骺端骨缺损的固定方式选择提供有价值的参考。
