Liu Bolun, Wang Huizhi, Zhang Ningze, Zhang Min, Cheng Cheng-Kung
Key Laboratory of Biomechanics and Mechanobiology, Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China.
School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China.
Front Bioeng Biotechnol. 2021 Nov 17;9:772539. doi: 10.3389/fbioe.2021.772539. eCollection 2021.
Cementless femoral stems are prone to stress shielding of the femoral bone, which is caused by a mismatch in stiffness between the femoral stem and femur. This can cause bone resorption and resultant loosening of the implant. It is possible to reduce the stress shielding by using a femoral stem with porous structures and lower stiffness. A porous structure also provides a secondary function of allowing bone ingrowth, thus improving the long-term stability of the prosthesis. Furthermore, due to the advent of additive manufacturing (AM) technology, it is possible to fabricate femoral stems with internal porous lattices. Several review articles have discussed porous structures, mainly focusing on the geometric design, mechanical properties and influence on bone ingrowth. However, the safety and effectiveness of porous femoral stems depend not only on the characteristic of porous structure but also on the macro design of the femoral stem; for example, the distribution of the porous structure, the stem geometric shape, the material, and the manufacturing process. This review focuses on porous femoral stems, including the porous structure, macro geometric design of the stem, performance evaluation, research methods used for designing and evaluating the femoral stems, materials and manufacturing techniques. In addition, this review will evaluate whether porous femoral stems can reduce stress shielding and increase bone ingrowth, in addition to analyzing their shortcomings and related risks and providing ideas for potential design improvements.
非骨水泥型股骨柄容易导致股骨的应力遮挡，这是由股骨柄与股骨之间的刚度不匹配引起的。这会导致骨吸收以及植入物随之松动。使用具有多孔结构和较低刚度的股骨柄可以减少应力遮挡。多孔结构还具有允许骨长入的次要功能，从而提高假体的长期稳定性。此外，由于增材制造（AM）技术的出现，制造具有内部多孔晶格的股骨柄成为可能。几篇综述文章讨论了多孔结构，主要集中在几何设计、力学性能以及对骨长入的影响。然而，多孔股骨柄的安全性和有效性不仅取决于多孔结构的特性，还取决于股骨柄的宏观设计；例如，多孔结构的分布、柄的几何形状、材料以及制造工艺。本综述聚焦于多孔股骨柄，包括多孔结构、柄的宏观几何设计、性能评估、用于设计和评估股骨柄的研究方法、材料以及制造技术。此外，本综述将评估多孔股骨柄是否能够减少应力遮挡并增加骨长入，同时分析其缺点和相关风险，并为潜在的设计改进提供思路。
