Affatato Saverio, Merola Massimiliano, Ruggiero Alessandro
Laboratorio di Tecnologia Medica, IRCCS-Istituto Ortopedico Rizzoli, 40136 Bologna, Italy.
Department of Industrial Engineering, University of Salerno, 84084 Salerno, Italy.
Materials (Basel). 2018 Jul 25;11(8):1282. doi: 10.3390/ma11081282.
A hip joint replacement is considered one of the most successful orthopedic surgical procedures although it involves challenges that must be overcome. The patient group undergoing total hip arthroplasty now includes younger and more active patients who require a broad range of motion and a longer service lifetime of the implant. The current replacement joint results are not fully satisfactory for these patients' demands. As particle release is one of the main issues, pre-clinical experimental wear testing of total hip replacement components is an invaluable tool for evaluating new implant designs and materials. The aim of the study was to investigate the cup tensional state by varying the clearance between head and cup. For doing this we use a novel hard-on-soft finite element model with kinematic and dynamic conditions calculated from a musculoskeletal multibody model during the gait. Four different usual radial clearances were considered, ranging from 0 to 0.5 mm. The results showed that radial clearance plays a key role in acetabular cup stress-strain during the gait, showing from the 0 value to the highest, 0.5, a difference of 44% and 35% in terms of maximum pressure and deformation, respectively. Moreover, the presented model could be usefully exploited for complete elastohydrodynamic synovial lubrication modelling of the joint, with the aim of moving towards an increasingly realistic total hip arthroplasty in silico wear assessment accounting for differences in radial clearances.
髋关节置换术被认为是最成功的骨科手术之一，尽管它面临着一些必须克服的挑战。接受全髋关节置换术的患者群体现在包括更年轻、更活跃的患者，他们需要广泛的活动范围和更长的植入物使用寿命。目前的置换关节结果对于这些患者的需求来说并不完全令人满意。由于颗粒释放是主要问题之一，全髋关节置换组件的临床前实验磨损测试是评估新植入物设计和材料的宝贵工具。该研究的目的是通过改变股骨头与髋臼杯之间的间隙来研究髋臼杯的张力状态。为此我们使用了一种新型的硬对软有限元模型，其运动学和动力学条件是根据步态期间的肌肉骨骼多体模型计算得出的。考虑了四种不同的常见径向间隙，范围从0到0.5毫米。结果表明，径向间隙在步态期间髋臼杯的应力应变中起关键作用，从0值到最高的0.5，最大压力和变形分别相差44%和35%。此外，所提出的模型可有效地用于关节的完整弹性流体动力滑膜润滑建模，目的是在考虑径向间隙差异的情况下，朝着越来越逼真的全髋关节置换术计算机模拟磨损评估发展。
