2nd Orthopaedic Department, Aristotle University of Thessaloniki, Thessaloniki, Macedonia 54124, Greece; E-Mails:
Int J Mol Sci. 2011;12(10):6597-618. doi: 10.3390/ijms12106597. Epub 2011 Oct 10.
In the present work, the crystallization behavior and in vitro-in vivo hydrolysis rates of PLA absorbable reinforcement ligaments used in orthopaedics for the repair and reinforcement of articulation instabilities were studied. Tensile strength tests showed that this reinforcement ligament has similar mechanical properties to Fascia Latta, which is an allograft sourced from the ilio-tibial band of the human body. The PLA reinforcement ligament is a semicrystalline material with a glass transition temperature around 61 °C and a melting point of ~178 °C. Dynamic crystallization revealed that, although the crystallization rates of the material are slow, they are faster than the often-reported PLA crystallization rates. Mass loss and molecular weight reduction measurements showed that in vitro hydrolysis at 50 °C initially takes place at a slow rate, which gets progressively higher after 30-40 days. As found from SEM micrographs, deterioration of the PLA fibers begins during this time. Furthermore, as found from in vivo hydrolysis in the human body, the PLA reinforcement ligament is fully biocompatible and after 6 months of implantation is completely covered with flesh. However, the observed hydrolysis rate from in vivo studies was slow due to high molecular weight and degree of crystallinity.
在本工作中，研究了用于矫形修复关节不稳定的可吸收增强韧带的结晶行为和体内外水解速率。拉伸强度测试表明，这种增强韧带具有与阔筋膜相似的机械性能，阔筋膜是一种同种异体移植物，来源于人体的髂胫束。PLA 增强韧带是一种半结晶材料，玻璃化转变温度约为 61°C，熔点约为 178°C。动态结晶表明，尽管材料的结晶速率较慢，但比经常报道的 PLA 结晶速率要快。质量损失和分子量降低测量表明，50°C 下的体外水解最初以较慢的速度进行，在 30-40 天后逐渐升高。从 SEM 显微照片中发现，在此期间 PLA 纤维开始恶化。此外，从人体内的水解发现，PLA 增强韧带是完全生物相容的，植入 6 个月后完全被肉覆盖。然而，由于高分子量和结晶度，体内研究观察到的水解速率较慢。
