目的 采用计算机模拟方法对比研究 ISO 14243 - 1 ∶ 2009 力控制标准测试条件下单髁膝关节置换术(unicompartmental knee arthroplasty,UKA)活动式与固定式衬垫的接触力学和磨损性能。 方法 采用有限元方法分析两种衬垫在测试条件下的接触应力和 von Mises 应力,并采用磨损预测模型模拟 5 MC(million cycles, 百万次循环)步态周期工况获得两种衬垫的线性磨损深度、磨损体积。 结果 磨损前活动式与固定式衬垫的最大接触应力分别为 15. 7、44. 3 MPa,最大 von Mises 应力分别为 11. 94、23. 33 MPa。 随着磨损加剧,活动式衬垫的最大接触应力和 von Mises 应力先减小后趋于稳定,而固定式衬垫的基本保持不变。 固定式衬垫的线性磨损深度为活动式的1. 5 倍,但活动式衬垫的磨损体积是固定式的 5. 4 倍,且活动式衬垫的背部磨损体积占其总磨损体积的 70% 。 结论 与固定式 UKA 衬垫相比,活动式 UKA 衬垫具有较低的接触应力与 von Mises 应力,但有较大的磨损体积。 活动式衬垫背部磨损是磨屑增加的另一个重要来源。

Objective To compare and study contact mechanics and wear performance of mobile- and fixed-bearing unicompartmental knee arthroplasty (UKA) under ISO 14243-1:2009 force control standard test condition by computational simulation. Methods The contact stress and von Mises stress of mobile- and fixed-bearing UKAs under the test condition were analyzed by finite element methods. The linear wear depth and wear volume of both UKA inserts were obtained after simulating gait with 5 million cycles (MCs) using wear prediction model. Results The maximum contact stresses of mobile- and fixed-bearing UKAs before wear were 15.7 MPa and 44.3 MPa respectively, and the maximum von Mises stresses were 11.94 MPa and 23.33 MPa respectively. With the increase of wear, the maximum contact stress and von Mises stress of the mobile-bearing UKA decreased first and then became stable, while that of the fixed-bearing UKA remained basically unchanged. The linear wear depth of fixed-bearing UKA was 1.5 times that of mobile-bearing UKA. But the wear volume of mobile-bearing UKA was 5.4 times that of fixed-bearing UKA, and the wear volume on backside surface accounted for 70% of the total wear volume of mobile-bearing UKA. Conclusions Compared with the fixed-bearing UKA, the mobile-bearing UKA had lower contact stress and von Mises stress, but larger wear volume. The backside wear of mobile-bearing UKA was an important source of increased wear debris.

国家自然科学基金项目（11902048，12102065，52035012），陕西省自然科学基金项目（2022JQ-529），长安大学中央高校基本科研业务费专项资金（300102252106）