Drillable magnesium phosphate cements in biomechanical evaluation: bone adhesive and bone substitute at same time.

矿物陶瓷作为骨替代物应用于临床已有一段时间。目前市场上可用的骨洞填充物的标准是羟基磷灰石水泥，它可以注射到骨缺损中，在很短的固化时间后已经变得非常坚固，可以继续进行外科骨折治疗。然而，这些骨水泥显示出缺乏对骨骼的重塑，这就是为什么以磷酸镁为基础的水泥是一种令人兴奋的替代选择。近年来，这些骨水泥在纯材料加载试验、真实骨折模型和活体动物模型中表现出令人信服的性能，表现在它们的力学性能、生物相容性和对骨的重塑方面。使用植酸(IP-6)作为液体成分，可以在本研究项目的初步研究中检测到两种磷酸镁粘固剂成分，除了这些理想的特性外，还针对临床应用进行了优化：除了可以在不同温度下注射外，它们还可以钻孔，甚至在钻孔过程和放置螺丝后，也进一步显示出高的轴向承载能力。当用植酸测试不同组成的磷酸镁水泥时，注意到一个有趣的副作用是这些水泥的所有表面都有粘结效应。这是一种副作用，对骨水泥的进一步临床应用非常有趣。该项目的目标是进一步将这些可钻孔和粘结剂粘结剂描述为适用于骨的“万能”粘结剂，集粘结剂和填充剂于一体。如果这两种特性可以结合在一种骨水泥中，这将彻底改变外科骨折治疗，尤其是关节多段骨折的治疗。为了更详细地研究这一非常有趣的潜在临床应用的新方面，首先建立了一个接近临床的骨折模型，该模型除了骨缺损外，还有一个用于粘合的间隙组件。利用猪的胫骨，对这种骨折模型进行评估，并分析一种新的手术技术，即一期解剖复位填充和粘合骨折。使用骨水泥和钢板接骨器组合的生物力学测试，将评估新的手术方法与以前使用的既定方法的强度差异。此外，还将在人骨骨折模型上对新型粘结剂和可钻性磷酸镁水泥的性能进行研究。本研究结果对植酸型磷酸镁骨水泥的可转移性和临床应用具有一定的参考价值。

Mineral ceramics as bone substitutes have been in clinical use for some time. The current commercially available standard for bone void fillers are hydroxyapatite cements, which can be injected into bony defects and after a short setting time already become so strong that surgical fracture treatment can be continued. However, these cements show a lack of remodeling to bone, even over years, which is why magnesium phosphate-based cements represent an exciting alternative. In recent years, these cements demonstrated convincing performance in loading tests as pure material tests, in realistic fracture models and in in vivo animal models with regard to their mechanical properties, their biocompatibility and their remodeling to bone. Using phytic acid (IP-6) as a liquid component, two compositions of magnesium phosphate cements could be detected in the preliminary study for this research project, which, in addition to these desirable properties, are optimized for clinical use: In addition to being injectable at different temperatures, they are drillable and further exhibit, even after the drilling process and placement of a screw, a high axial load-bearing capacity. An interesting side effect that was noticed when testing different compositions of the magnesium phosphate cements with phytic acid was the adhesive effect on all surfaces of these cements. This is a side-effect that is extremely interesting for further clinical application of the cements. The aim of this project is now to further characterize these drillable and adhesive cements as "all-rounders" for application to bone, as an adhesive and filler in one. If both properties can be combined in one cement, this would revolutionize surgical fracture treatment, especially for articular multi-fragment fractures. In order to investigate this highly interesting new aspect of potential clinical application in more detail, a close to clinic fracture model is first established, which has beside a bony defect and a gap component for bonding. Using porcine tibia bones, this fracture model will be evaluated and a new surgical technique of filling and gluing this fracture with primary anatomic reduction will be analyzed. Using biomechanical tests of combinations of bone cements and plate osteosyntheses, the new surgical method will be evaluated for strength differences from the previously used, established method. In addition, the properties of the new adhesive and drillable magnesium phosphate cements will be investigated in the fracture model on human bone. Valuable results for the transferability and clinical application of magnesium phosphate cement with phytic acid are expected from the findings.