UKA假体后倾角安装位置对衬垫磨损的影响

目的 研究单髁膝关节置换(unicompartmental knee arthroplasty, UKA)假体不同后倾角度安装对膝关节承载、运动及衬垫磨损的影响。方法 联合UKA骨肌多体动力学模型、有限元模型和磨损模型，分析固定式UKA假体5种后倾角安装位置情况对术后膝关节力和运动、衬垫接触应力、线性磨损深度和体积磨损量的影响。结果 后倾角0°时，衬垫的最大von Mises等效应力为24.84 MPa,接触应力为47.61 MPa, 5百万次循环(million cycle, MC)周期的磨损量为47.29 mm³。随着UKA胫骨假体后倾角的增加，步态周期内旋和后移运动均增大，摆动相的内侧关节力增大，5 MC磨损周期后衬垫von Mises等效应力与接触应力显著减小，衬垫的磨损面积、最大线性磨损深度和体积磨损量随之减少。相对于后倾角0°,后倾角为3°、5°、7°时衬垫的线性磨损深度分别减小了17.8%、19.2%、20.6%;衬垫体积磨损量分别下降了24.5%、30.9%、34.3%。结论 UKA假体考虑后倾角安装超过3°时会显著增加步态周期内旋运动和后移运动，...

Effects of Posterior Slope Installation Position of UKA Prosthesis on Insert Wear

Objective To study the effects of different posterior slope installations of unicompartmental knee arthroplasty (UKA) prostheses on the loading and motion of the knee joint and insert wear. Methods A combined approach involving The UKA musculoskeletal multibody dynamic, finite element, and wear prediction models was used to investigate the effects of five different posterior slope installation positions of the UKA prosthesis on the postoperative knee joint force and motion, insert contact stress, linear wear depth, and wear volume. Results At a 0° posterior slope, the maximum von Mises stress of the insert was 24.84 MPa, maximum contact stress was 47.61 MPa, and volumetric wear after 5 million cycles (MC) was 47.29 mm3. As the posterior slope angle of the UKA prosthesis increased, the internal rotation and posterior translation during the gait cycle increased, the medial joint force during the swing phase increased, the von Mises and contact stresses of the insert after 5 MC decreased significantly, and the wear area, maximum linear wear depth, and volumetric wear volume of the insert were consequently reduced. Compared to the 0° posterior slope, the linear wear depths of the insert at the 3°, 5°, and 7°posterior slopes decreased by 17.8%, 19.2%, and 20.6%, respectively. The volumetric wear volumes of the inserts decreased by 24.5%, 30.9%, and 34.3%, respectively. Conclusion Installing a UKA prosthesis with a posterior slope exceeding 3° significantly increases internal rotation and posterior translation during the gait cycle, further reducing the articular volumetric wear of the polyethylene insert.