Brendle Saskia A, Krueger Sven, Grifka Joachim, Müller Peter E, Mihalko William M, Richter Berna, Grupp Thomas M
Research & Development, Aesculap AG, 78532 Tuttlingen, Germany.
Department of Orthopaedic and Trauma Surgery, Musculoskeletal University Center Munich (MUM), Campus Grosshadern, LMU Munich, 81377 Munich, Germany.
Bioengineering (Basel). 2025 Jan 19;12(1):87. doi: 10.3390/bioengineering12010087.
Instability remains one of the most common indications for revision after total knee arthroplasty. To gain a better understanding of how an implant will perform in vivo and support surgeons in selecting the most appropriate implant design for an individual patient, it is crucial to evaluate the implant constraint within clinically relevant ligament and boundary conditions. Therefore, this study investigated the constraint of three different implant designs (symmetrical implants with and without a post-cam mechanism and an asymmetrical medial-stabilized implant) under anterior-posterior shear forces and internal-external rotation moments at different flexion angles in human cadaveric knees using a six-degrees-of-freedom joint motion simulator. Both symmetrical designs showed no significant differences between the anterior-posterior range of motion of the medial and lateral condyles. In contrast, the medial-stabilized implant exhibited less anterior-posterior translation medially than laterally, without constraining the medial condyle to a fixed position. Furthermore, the post-cam implant design showed a significantly more posterior position of the femoral condyles in flexion compared to the other designs. The results show that despite the differences in ligament situations and individual implant positioning, specific characteristics of each implant design can be identified, reflecting the different geometries of the implant components.
膝关节置换术后不稳定仍然是最常见的翻修指征之一。为了更好地了解植入物在体内的性能，并帮助外科医生为个体患者选择最合适的植入物设计，在临床相关的韧带和边界条件下评估植入物的约束力至关重要。因此，本研究使用六自由度关节运动模拟器，在人体尸体膝关节的不同屈曲角度下，研究了三种不同植入物设计（有无后凸轮机制的对称植入物和不对称内侧稳定植入物）在前-后剪切力和内-外旋转力矩作用下的约束力。两种对称设计在内侧和外侧髁的前-后运动范围内均未显示出显著差异。相比之下，内侧稳定植入物在内侧的前-后平移比外侧少，且未将内侧髁限制在固定位置。此外，与其他设计相比，后凸轮植入物设计在屈曲时股骨髁的位置明显更靠后。结果表明，尽管韧带情况和个体植入物位置存在差异，但每种植入物设计的特定特征是可以识别的，这反映了植入物组件的不同几何形状。
