Dai Huiyong, Zheng Nan, Zou Diyang, Zhu Zhemin, Liow Ming Han Lincoln, Tsai Tsung-Yuan, Wang Qi
Department of Orthopedics, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China.
School of Biomedical Engineering and Med-X Research Institute, Shanghai Jiao Tong University, Shanghai, China.
Front Bioeng Biotechnol. 2021 May 20;9:666435. doi: 10.3389/fbioe.2021.666435. eCollection 2021.
While wear simulation of unicompartmental knee arthroplasty (UKA) showed outstanding long-term wear performance, studies reported that polyethylene (PE) wear was responsible for 12% fixed-bearing (FB) UKA failure. This paper aimed to quantify the 6-degrees-of-freedom (6-DOF) knee kinematics and contact positions of FB UKA during daily activities and compare with the previous results of wear simulator.
Fourteen patients following unilateral medial FB UKA received a CT scan and dual fluoroscopic imaging during level walking, single-leg deep lunge, and sit-to-stand motion for evaluating 6-DOF FB UKA kinematics. The closest point between surface models of the femoral condyle and PE insert was determined to locate the medial compartmental articular contact positions, which were normalized relative to the PE insert length. The contact area was compared with the wear region in previous simulator studies.
The contact positions during daily activities were more anterior than those in the previous wear simulator studies ( < 0.001). Significant differences in the femoral anteroposterior translation and tibial internal rotation during the stance phase were observed and compared with those in lunge and sit-to-stand motions ( < 0.05). The contact position located anteriorly and medially by 5.2 ± 2.7 and 1.8 ± 1.6 mm on average for the stance phase, 1.0 ± 2.4 and 0.9 ± 1.5 mm for the lunge, and 2.1 ± 3.3 and 1.4 ± 1.4 mm for sit-to-stand motion. The contact position was in the more anterior part during the stance phase ( < 0.05).
The current study revealed that the contact position of FB UKA was located anteriorly and medially on the PE insert during weight-bearing activities and different from previous findings of the wear simulator. We should take 6-DOF knee kinematics and contact patterns of FB UKA into account to reproduce realistic wear performance for wear simulator and to improve implant design.
虽然单髁膝关节置换术（UKA）的磨损模拟显示出出色的长期磨损性能，但研究报告称，聚乙烯（PE）磨损是导致12%的固定平台（FB）UKA失败的原因。本文旨在量化FB UKA在日常活动中的六自由度（6-DOF）膝关节运动学和接触位置，并与先前磨损模拟器的结果进行比较。
14名单侧内侧FB UKA患者在平步行走、单腿深蹲和从坐到站运动期间接受了CT扫描和双荧光透视成像，以评估6-DOF FB UKA的运动学。确定股骨髁表面模型与PE垫片之间的最近点，以定位内侧间室关节接触位置，并相对于PE垫片长度进行归一化。将接触面积与先前模拟器研究中的磨损区域进行比较。
日常活动中的接触位置比先前磨损模拟器研究中的更靠前（P<0.001）。观察到站立期股骨前后平移和胫骨内旋的显著差异，并与深蹲和从坐到站运动中的差异进行比较（P<0.05）。站立期接触位置平均向前和向内分别为5.2±2.7和1.8±1.6mm，深蹲时为1.0±2.4和0.9±1.5mm，从坐到站运动时为2.1±3.3和1.4±1.4mm。站立期接触位置更靠前（P<0.05）。
当前研究表明，FB UKA在负重活动期间的接触位置位于PE垫片的前内侧，与先前磨损模拟器的结果不同。我们应考虑FB UKA的6-DOF膝关节运动学和接触模式，以便为磨损模拟器再现逼真的磨损性能并改进植入物设计。
