Schumacher Thomas C, Tushtev Kamen, Wagner Ulrich, Becker Caroline, Große Holthaus Marzellus, Hein Sebastian B, Haack Janne, Heiss Christian, Engelhardt Markus, El Khassawna Thaqif, Rezwan Kurosch
Advanced Ceramics, University of Bremen, 28359 Bremen, Germany.
Advanced Ceramics, University of Bremen, 28359 Bremen, Germany.
Knee. 2017 Oct;24(5):933-939. doi: 10.1016/j.knee.2017.07.005. Epub 2017 Jul 26.
Rupture of the anterior cruciate ligament (ACL) is one of the most common injuries of the knee. Common techniques for ACL reconstruction require a graft fixation using interference screws. Nowadays, these interference screws are normally made of titanium or polymer/ceramic composites. The main challenge of application of a fixation device made entirely of bioactive ceramic is in relation to the low strength of such materials. The purpose of this study was to evaluate a novel geometry for a fixation device made of pure hydroxyapatite for ACL reconstructions that can overcome some problems of the titanium and the polymer/ceramic screws.
Finite Element Analysis was used for optimization of the stress distribution in conventional interference screw geometry. For experimental evaluation of the new fixation device, ex vivo tests were performed.
The innovative screw-like fixation device is characterized by multiple threads with a large thread pitch. The novel design enabled the insertion of the screw into the bone without the application of an external torque or a screwdriver. In turn, it also allowed for the use of low-strength and high-bioactivity materials, like hydroxyapatite. Ex vivo tests showed that the novel screw can sustain pull-out forces up to 476 N, which is comparable to that of the commercially available BioComposite™ interference screws (Arthrex Inc., Germany), as a reference.
In summary, the novel screw design is a promising strategy to develop all-ceramic fixation devices for ACL reconstructions, which may eliminate some drawbacks of the current interference screws.
前交叉韧带（ACL）断裂是膝关节最常见的损伤之一。ACL重建的常用技术需要使用干涉螺钉进行移植物固定。如今，这些干涉螺钉通常由钛或聚合物/陶瓷复合材料制成。完全由生物活性陶瓷制成的固定装置应用的主要挑战在于此类材料强度较低。本研究的目的是评估一种用于ACL重建的由纯羟基磷灰石制成的固定装置的新型几何形状，该形状可克服钛螺钉和聚合物/陶瓷螺钉的一些问题。
使用有限元分析来优化传统干涉螺钉几何形状中的应力分布。为了对新的固定装置进行实验评估，进行了体外测试。
这种创新的螺钉状固定装置的特点是具有大螺距的多螺纹。这种新颖的设计使得螺钉无需施加外部扭矩或螺丝刀即可插入骨中。反过来，它也允许使用低强度和高生物活性的材料，如羟基磷灰石。体外测试表明，这种新型螺钉能够承受高达476 N的拔出力，作为参考，这与市售的BioComposite™干涉螺钉（德国Arthrex公司）相当。
总之，这种新颖的螺钉设计是开发用于ACL重建的全陶瓷固定装置的一种有前景的策略，这可能消除当前干涉螺钉的一些缺点。
