Edge loading in ceramic-on-ceramic total hip joint replacement is an adverse condition that occurs as the result of a direct contact between the head and the cup rim. It has been associated with translational mismatch in the centres of rotation of the cup and head, and found to cause severe wear and early failure of the implants. Edge loading has been considered in particular in relation to dynamic separation of the cup and head centres during a gait cycle. Research has been carried out both experimentally and computationally to understand the mechanism including the influence of bearing component positioning on the occurrence and severity of edge loading. However, it is experimentally difficult to measure both the load magnitude and duration of edge loading as it occurs as a short impact within the tight space of hip joints. Computationally, a dynamic contact model, for example, developed using the MSC ADAMS software for a multi-body dynamics simulation can be particularly useful for calculating the loads and characterising the edge loading. The aim of the present study was to further develop the computational model, and improve the predictions of contact force and the understanding of mechanism in order to provide guidance on design and surgical factors to avoid or to reduce edge loading and wear. The results have shown that edge loading can be avoided for a low range of translational mismatch in the centres of rotation of the cup and head during gait at the level of approximately 1.0 mm for a cup at 45 °inclination, keeping a correct cup inclination at 45 °is important to reduce the edge loading severity, and edge loading can be avoided for a certain range of translational mismatch of the cup and head centres with an increased swing phase load.

陶瓷-陶瓷全髋关节置换术中的边缘负荷是由于头部与杯缘直接接触而产生的不利条件。它与杯和头的旋转中心的平移不匹配有关，并被发现会导致严重的磨损和植入物的早期失效。尤其在步态周期中考虑到边缘载荷与杯子和头部中心的动态分离有关。已经通过实验和计算方式进行了研究，以了解这种机理，包括轴承部件定位对边缘载荷的发生和严重性的影响。但是，在实验上很难同时测量负荷大小和边缘负荷的持续时间，因为它是在髋关节狭窄空间内的短暂撞击而发生的。计算上 例如，使用MSC ADAMS软件开发的用于多体动力学仿真的动态接触模型对于计算载荷和表征边缘载荷特别有用。本研究的目的是进一步开发计算模型，改善对接触力的预测和对机构的理解，从而为避免或减少边缘载荷和磨损的设计和手术因素提供指导。结果表明，对于步态在45°倾斜的杯子来说，步态期间杯和头部的旋转中心的平移不匹配范围较小，可以避免边缘载荷，在大约1.0 mm的水平上，保持了正确的杯倾斜度。 45°对于降低边缘载荷的严重性很重要，