National Engineering Laboratory for Highway Maintenance Equipment, Chang'an University, 710064 Xi'an, Shaanxi, China.
State Key Laboratory for Manufacturing System Engineering, School of Mechanical Engineering, Xi'an Jiaotong University, 710049 Xi'an, Shaanxi, China.
J Healthc Eng. 2020 Mar 14;2020:8103523. doi: 10.1155/2020/8103523. eCollection 2020.
Dual mobility hip implants have been widely introduced to overcome dislocation in recent years. However, the potential influence of different gaits on kinematics and contact mechanics for dual mobility hip implants is still unclear. Furthermore, a large range of motion coupling with the implant position, especially high inclination or anteversion angle, may result in poor kinematics and contact mechanics. A previously developed dynamic finite element method was adopted in this study to examine the kinematics and corresponding stability of dual mobility hip implants under different gaits coupling with different inclinations or anteversion angles. The results showed only inner relative sliding under knee-bending for dual mobility hip implants under moderate inclination and anteversion angles, whereas an anteversion angle of 25° induced both impingement and consequent relative sliding of the outer articulation. However, the impingement (between the stem neck and the liner inner rim) indeed happened under stair-climbing and sitting-down/stand-up as well as combined movements when inclination and anteversion angles were set as 45° and 0°, respectively, and this finally led to relative sliding at the outer articulation. A high inclination angle did not worsen both the impingement and related outer sliding compared to modest inclination and anteversion angles of the liner, but a high anteversion angle prolonged the period of both the impingement and the outer relative sliding. The extreme motions and high anteversion angles are hardly inevitable, and they indeed lead to motions at both articulations for dual mobility hip implants.
近年来，双动髋关节假体广泛应用于临床以降低髋关节脱位的发生率。然而，不同步态对双动髋关节假体的运动学和接触力学的潜在影响仍不清楚。此外，大范围的运动与假体位置相关联，特别是高倾斜或前倾角，可能导致不良的运动学和接触力学。本研究采用先前开发的动态有限元方法，研究了不同倾斜或前倾角与不同步态耦合时双动髋关节假体的运动学及其相应的稳定性。结果表明，在中度倾斜和前倾角下，双动髋关节假体在膝关节弯曲时仅发生内相对滑动，而前倾角为 25°时会导致外关节撞击和随之而来的外关节相对滑动。然而，在倾斜和前倾角分别设置为 45°和 0°的情况下，在爬楼梯、坐下/站立以及组合运动时，确实会发生撞击（在柄颈和衬里内缘之间），最终导致外关节相对滑动。与适度的衬里倾斜和前倾角相比，高倾斜角并不会增加撞击和相关的外滑动，但高前倾角会延长撞击和外相对滑动的时间。极端运动和高前倾角很难避免，它们确实会导致双动髋关节假体在两个关节处运动。
