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

矿物陶瓷作为骨代用品在临床应用已有一段时间。目前市面上可获得的骨空隙填充物标准是羟基磷灰石水泥，它可以注射到骨缺损中，在短暂的凝固时间后已经变得非常坚固，可以继续进行骨折手术治疗。然而，这些水泥缺乏骨重塑，即使经过几年，这就是为什么磷酸镁基水泥是一个令人兴奋的选择。近年来，这些骨水泥在纯材料加载试验、真实骨折模型和体内动物模型中表现出令人信服的力学性能、生物相容性和骨重塑性能。使用植酸（IP-6）作为液体成分，在本研究项目的初步研究中可以检测到两种磷酸镁胶结物，除了这些理想的性能外，它们还被优化用于临床应用：除了在不同温度下可注射外，它们还可钻孔，并且即使在钻孔过程和放置螺钉之后，也具有较高的轴向承载能力。在用植酸测试磷酸镁水泥的不同成分时，我们注意到一个有趣的副作用，那就是在这些水泥的所有表面上都有粘合作用。这一副作用对水泥的进一步临床应用非常有趣。该项目的目的是进一步将这些可钻孔和粘合的水泥作为“全能”应用于骨骼，作为粘合剂和填充物于一体。如果这两种特性可以结合在一种水泥中，这将彻底改变外科骨折治疗，特别是关节多碎片骨折。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成分。我们将以猪胫骨为研究对象，对这种骨折模型进行评估，并分析一种新的手术技术，即通过初次解剖复位来填充和粘合这种骨折。通过对骨水泥和钢板接骨术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中研究新型黏结性和可钻性磷酸镁胶结物的性能。该研究结果有望为植酸磷酸镁骨水泥的可转移性和临床应用提供有价值的结果。

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.