Kinematic Alignment in Cruciate Retaining Implants Improves the Biomechanical Function in Total Knee Arthroplasty during Gait and Deep Knee Bend

Abstract

Kinematic alignment (KA), which co-aligns the rotational axes of the components with three kinematic axes of the knee by aligning the components to the prearthritic joint lines, has been a recently introduced surgical technique. However, whether KA and cruciate retaining (CR) implants provide better biomechanical function during activities than mechanical alignment (MA) in posterior stabilized (PS) implants is unclear. We evaluated the biomechanical functions during the stance phase gait and deep knee bend, with a computer simulation and measured forces in the medial and lateral collateral ligaments and medial and lateral contact stresses in the polyethylene insert and patellar button. The forces on the medial collateral ligament in KA were lower than those in MA in both CR and PS TKA in the stance phase gait and deep knee bend conditions, whereas those on the lateral collateral ligament did not show any difference between the two surgical alignment techniques in the stance phase gait condition. The maximum contact stresses on the medial PE inserts in KA were lower than those in MA in both CR and PS TKA in the stance phase gait and deep knee bend conditions. However, the maximum contact stresses on the lateral PE inserts and the patellar button did not differ between MA and KA. The biomechanical function was superior in KA TKA than in MA TKA, and KA was more effective in CR TKA. This comparison could be used as a reference by surgeons to reduce the failure rates by using KA TKA instead of MA TKA.

Kinematic Alignment in Total Knee Arthroplasty Reduces Polyethylene Contact Pressure by Increasing the Contact Area, When Compared to Mechanical Alignment—A Finite Element Analysis

“…Recent studies corroborate our findings, which might be due to better models, but also due to a better understanding of KA philosophy by respecting the patient-specific anatomy. Kang et al [ 10 ] investigated a cruciate retaining implant in a single patient and found improved kinematics of KA over MA, with reduced pressure due to the increased area, as observed in the present study. Von Mises stresses observed in the present study might indicate the reason for loosening in some valgus knees, since the stresses are increased on the polytheylene metal interface.…”

“…Similarly, earlier finite element (FE) analyses found improved kinematics of KA over MA, but with increased contact stresses [ 9 ]. More recent FE studies have shown decreased stresses [ 10 ] or no difference [ 11 ].…”

Application strategy of finite element analysis in artificial knee arthroplasty

“…Thus, the artificial knee joint can simulate the normal biomechanical state of the human knee joint as much as possible after the operation. Kang et al (2020) studied ligament-preserving prostheses and found that KA had better mobility and even stress distribution than MA. Klasan et al (2022) established a finite element model for 10 patients with knee osteoarthritis to simulate TKA with mechanical alignment and kinematic alignment.…”

Computational biomechanics of knee joint arthroplasty : a review

“…Computational studies have been performed in the field on aspects other than misalignment of components (Fitzpatrick et al, 2016;Kang et al, 2019a;Nakamura et al, 2017). Nakamura et al investigated the kinematics, contact forces and stress, and bone strain in kinematically aligned (KA) and mechanically aligned (MA) TKA using computational simulation (Nakamura, Tian, Tanaka, Kuriyama, Ito, Furu and Matsuda, 2017).…”