Park K D, Park J B
Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa 52242-1527, USA.
J Biomed Mater Res. 2000;53(6):737-47. doi: 10.1002/1097-4636(2000)53:6<737::aid-jbm17>3.0.co;2-5.
The interface between bone cement and ultra-high molecular weight polyethylene (UHMWPE) has been considered a weak link of cemented UHMWPE acetabular cup in total hip replacement (THR). For the improvement of this weak interface, adhesion between the UHMWPE acetabular cup and bone cement made of polymethylmethacrylate (PMMA) has been investigated in our laboratory. Virgin UHMWPE powders were treated with methyl methacrylate (MMA) monomer and PMMA/MMA solution. The treated UHMWPE powders were then compression-molded with virgin UHMWPE powders or PMMA powders, creating two different interfaces, i. e., treated/virgin UHMWPE powder and treated UHMWPE/PMMA powder. For the present study, the interfacial strengths between PMMA powder and the treated UHMWPE power were investigated following the same protocol previously set. The maximum interfacial strength was 17.0 +/- 0.25MPa with the same molding condition of 166.5 degrees C, 38.7 MPa and l h. In addition to the molding condition, we tested the strengths for the treated UHMWPE powders, which have different ratios between PMMA/MMA solution and MMA-treated UHMWPE powders. Significant differences on the interfacial strengths resulted due to the ratio change; more PMMA in the PMMA/MMA solution-treated UHMWPE powder exhibited higher interfacial strength. Scanning electron microscopic (SEM) pictures showed that the interface is composed of three major portions: PMMA powder, UHMWPE, and coated PMMA, indicating strong mechanical interlocking of UHMWPE and PMMA powder matrix and chemical bonding between PMMA powder and the precoated PMMA onto the UHMWPE. In addition, another interfacial strength between PMMA powder, which is equivalent to the outermost part of the cup, and bone cement was investigated. The average strength reached up to 42.4 +/- 3.6 MPa, close to the tensile strength of bone cement itself.
在全髋关节置换术（THR）中，骨水泥与超高分子量聚乙烯（UHMWPE）之间的界面一直被认为是骨水泥型UHMWPE髋臼杯的薄弱环节。为了改善这个薄弱界面，我们实验室对UHMWPE髋臼杯与聚甲基丙烯酸甲酯（PMMA）制成的骨水泥之间的附着力进行了研究。将原始UHMWPE粉末用甲基丙烯酸甲酯（MMA）单体和PMMA/MMA溶液处理。然后将处理过的UHMWPE粉末与原始UHMWPE粉末或PMMA粉末进行压缩成型，形成两种不同的界面，即处理过的/原始UHMWPE粉末界面和处理过的UHMWPE/PMMA粉末界面。在本研究中，按照先前设定的相同方案研究了PMMA粉末与处理过的UHMWPE粉末之间的界面强度。在166.5℃、38.7MPa和1小时的相同成型条件下，最大界面强度为17.0±0.25MPa。除成型条件外，我们还测试了处理过的UHMWPE粉末的强度，这些粉末在PMMA/MMA溶液与MMA处理过的UHMWPE粉末之间具有不同的比例。由于比例变化，界面强度产生了显著差异；PMMA/MMA溶液处理过的UHMWPE粉末中PMMA含量越高，界面强度越高。扫描电子显微镜（SEM）照片显示，界面由三个主要部分组成：PMMA粉末、UHMWPE和包覆的PMMA，表明UHMWPE与PMMA粉末基体之间有很强的机械互锁，以及PMMA粉末与预涂覆在UHMWPE上的PMMA之间有化学键合。此外，还研究了与髋臼杯最外层等效的PMMA粉末与骨水泥之间的另一种界面强度。平均强度达到42.4±3.6MPa，接近骨水泥本身的拉伸强度。
