Affatato Saverio, Erani Paolo, Fersini Maurizio, Contaldi Vincenzo, Terrizzi Anna Rita, Licciulli Antonio
Laboratorio di Tecnologia Medica, IRCCS Istituto Ortopedico Rizzoli, 40136 Bologna, Italy.
SALENTEC s.r.l., 73100 Lecce, Italy.
Materials (Basel). 2021 Apr 22;14(9):2112. doi: 10.3390/ma14092112.
Success of total knee replacement (TKR) depends on the prosthetic design and materials. The use of metal components is well established with the disadvantage of allergic reactions. Ceramics have been recently proposed because of high wear resistance, excellent biocompatibility, wettability, and suitable mechanical properties. This study was aimed at investigating in vitro wear resistance of Zirconia Toughened Alumina (ZTA)/Ultra-high-molecular-weight polyethylene (UHMWPE) of TKR femoral components. An in vitro protocol was designed with the application of relevant load profile, 6-degrees-of-freedom knee simulator, and 8 × 10 cycles on the ZTA/UHMWPE configuration under bovine calf serum. Before and after wear test, the femoral components were investigated by using the Scanning Electron Microscope (SEM) and the X-Ray Diffraction (XRD) analyses, and stylus surface roughness measurements. The proposed pre-clinical test yielded repeatable results. In particular, gravimetric results showed that, after 8 × 10 cycles, the mean weight loss of the polyethylene mobile components is 5.3 ± 1.1 mg. The surface roughness measurements (Ra) performed after the wear test showed no significant variation on the UHMWPE menisci. A slight increase of roughness has been found on the ZTA (0.02 µm before wear test, 0.28 µm after the test). SEM observations did not show significant modification of the surface morphology. Tetragonal to monoclinic phase ratio was measured by XRD before and after wear test to evaluate stability of tetragonal ZrO phase. Minimal conversion of tetragonal to monoclinic phase was found from 5.4 to 8%. Although this study is a preliminary evaluation limited to in vitro tests, it provides novel pre-clinical indications about the potential of ceramic TKR femoral components.
全膝关节置换术（TKR）的成功取决于假体设计和材料。金属部件的使用已很成熟，但存在过敏反应的缺点。由于具有高耐磨性、优异的生物相容性、润湿性和合适的机械性能，陶瓷材料最近被提出来。本研究旨在调查TKR股骨部件的氧化锆增韧氧化铝（ZTA）/超高分子量聚乙烯（UHMWPE）的体外耐磨性。设计了一种体外实验方案，在牛犊血清中对ZTA/UHMWPE组合施加相关载荷曲线、六自由度膝关节模拟器，并进行8×10次循环。在磨损试验前后，通过扫描电子显微镜（SEM）、X射线衍射（XRD）分析和触针表面粗糙度测量对股骨部件进行研究。所提出的临床前试验产生了可重复的结果。特别是，重量分析结果表明，在8×10次循环后，聚乙烯活动部件的平均重量损失为5.3±1.1毫克。磨损试验后进行的表面粗糙度测量（Ra）显示，UHMWPE半月板没有显著变化。在ZTA上发现粗糙度略有增加（磨损试验前为0.02µm，试验后为0.28µm）。SEM观察未显示表面形态有显著改变。通过XRD在磨损试验前后测量四方相到单斜相的比例，以评估四方ZrO相的稳定性。发现四方相到单斜相的转化率最低，从5.4%到8%。尽管本研究是仅限于体外试验的初步评估，但它提供了关于陶瓷TKR股骨部件潜力的新的临床前指标。
