Castellarin Gianluca, Bori Edoardo, Menon Alessandra, Innocenti Bernardo
II Unit Orthopaedic Department, Ospedale di Suzzara, Mantova, Italy.
Université Libre de Bruxelles, École Polytechnique de Bruxelles, BEAMS Department (Bio Electro and Mechanical Systems), Brussels, Belgium.
J Orthop. 2022 Aug 10;34:89-93. doi: 10.1016/j.jor.2022.07.018. eCollection 2022 Nov-Dec.
Total knee arthroplasty has proved to be a safe, effective and reproducible surgical treatment for patients with serious/advanced degenerative joint disease of the knee, but the optimal results after these implants can be achieved only if the joint kinematics and kinetics are carefully respected and not significantly altered after the replacement. In order to enhance the capability of matching the healthy configuration, therefore, different prosthesis models in terms of constraints and designs are available for the surgeons to choose among. As an example of this variety, mobile bearing models allow the surgeon to choose among different insert designs in terms of geometry and relative biomechanical approaches, with the relative performances depending on which one is adopted.This article aims to analyse the effect of different levels of congruency of mobile bearing inserts through an experimental activity performed on an ultra-congruent insert design, also referred as deep-dished.
The experimental activity followed the same protocol used in a previous study focused on the effect of symmetricity/asymmetricity (in order to allow a comparison among the results obtained), i.e. it analysed passive squat on 5 cadaveric knee specimens; internal-external rotations of femur and tibial insert respect to the tibia tray were thus measured via a motion capture system in order to compare the insert-femur relative rotation among the different congruency configurations.
The overall knee kinematic (in terms of flexion-extension and internal-external rotation ranges of motion) with an ultra-congruent insert did not differ from the ones found for the other inserts; the insert-femur rotation values, instead, returned to be between the ones obtained with the other two inserts.
In terms of adaptability to tibio-femoral rotation, therefore, this insert represents a valid option for the surgeon seeking for an intermediate solution among the opposed approaches of the other two.
全膝关节置换术已被证明是治疗严重/晚期膝关节退行性关节疾病患者的一种安全、有效且可重复的手术治疗方法，但只有在关节运动学和动力学得到仔细尊重且置换后未发生显著改变的情况下，才能获得这些植入物的最佳效果。因此，为了提高匹配健康结构的能力，外科医生可以在不同约束和设计的不同假体模型中进行选择。作为这种多样性的一个例子，活动轴承模型允许外科医生根据几何形状和相对生物力学方法在不同的插入物设计中进行选择，其相对性能取决于所采用的设计。本文旨在通过对一种超贴合插入物设计（也称为深盘状）进行的实验活动，分析活动轴承插入物不同贴合程度的影响。
实验活动遵循了先前一项关于对称性/非对称性影响的研究中使用的相同方案（以便能够比较所获得的结果），即分析了5个尸体膝关节标本上的被动下蹲；通过运动捕捉系统测量股骨和胫骨插入物相对于胫骨托的内外旋转，以便比较不同贴合配置下插入物与股骨的相对旋转。
使用超贴合插入物时的整体膝关节运动学（在屈伸和内外旋转运动范围内）与其他插入物所发现的运动学没有差异；相反，插入物与股骨的旋转值回到了用其他两种插入物获得的值之间。
因此，就对胫股旋转的适应性而言，对于寻求在其他两种相反方法之间找到中间解决方案的外科医生来说，这种插入物是一个有效的选择。
