Importance of joint line preservation in unicompartmental knee arthroplasty: Finite element analysis

Abstract

Unicompartmental knee arthroplasty (UKA) is an effective surgical technique for pain relief and functional restoration in patients with localized osteoarthritis of the knee joint. However, the role of the joint line in UKA, especially its biomechanical effect, has not been previously investigated. This study numerically evaluates the effects of the joint line on the contact stresses in polyethylene (PE) inserts, articular cartilage, and lateral meniscus using the finite element (FE) analysis. The FE model for joint line was modeled as the orthogonal projection line from the medial tibial plateau to the anatomical axis. The joint line was varied from -6 to +6 mm in 2 mm intervals, and the seven FE models were analyzed and compared under ISO gait loading conditions. The contact stresses in the PE insert, articular cartilage, and lateral meniscus matched those of the reference joint line (0 mm) in the ±2 and ±4 mm joint line cases but significantly differed from the reference in the ±6 mm joint line cases. On the +6 mm joint line, the contact stress was greater on the PE insert than on the articular cartilage, whereas the reverse occurred on the -6 mm joint line. This study confirms the post-operative significance of joint line preservation in UKA implantation surgery. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:347-352, 2017.

Finite Element Study on the Preservation of Normal Knee Kinematics with Respect to the Prosthetic Design in Patient-Specific Medial Unicompartmental Knee Arthroplasty

“…Six pairs of TF contact between the femoral cartilage and the meniscus, the meniscus and the tibial cartilage, and the femoral cartilage and the tibial cartilage were modeled for both the medial and lateral sides of the joint [18,21]. The heights of the tibial insert for three different designs were matched to the original bone anatomy using a sagittal cross-sectional image, then aligned with the mechanical axis, and positioned at the medial edge with a square (0°) inclination in the coronal plane of the tibia [18,21,34]. The rotating alignment was defined as the line parallel to the lateral edge of the tibial baseplate passing the center of the femoral component fixation peg.…”

“…The femoral component, PE insert, and tibial baseplate materials were cobaltchromium alloy (CoCr), UHMWPE, and titanium alloy (Ti6Al4V), respectively. According to previously published data, the material properties, in terms of Young's Modulus : E = 110 GPa, ν = 0:3 [34][35][36]. Solid modelling and meshing were performed by using Hypermesh 11.0 (Altair Engineering, Inc., Troy, Michigan).…”

Computational biomechanics of knee joint arthroplasty : a review

“…However, recent studies have focused not only on stress or strain on bone, but also looked at stress on soft tissue. Therefore, modeling not only of the femur, but also of cartilage and the lateral meniscus became required (Innocenti et al, 2014;Innocenti et al, 2016;Kang et al, 2018f;Kang et al, 2019c;Kang et al, 2018h;Kang et al, 2018i;Kang et al, 2018j;Kwon et al, 2014;Kwon et al, 2017;Park et al, 2019;Simpson, Price, Gulati, Murray and Gill, 2009;Wen et al, 2017;Zhu et al, 2015).…”

Computational analysis of customized cruciate retaining total knee arthroplasty restoration of native knee joint biomechanics

“…The interfaces between the articular cartilage and the bones were considered to be fully bonded (22)(23)(24). Six pairs of tibiofemoral contacts between the femoral cartilage and the meniscus, the meniscus and the tibial cartilage, and the femoral cartilage and the tibial cartilage were modeled for both the medial and lateral sides (25). A finite sliding frictionless hard contact algorithm with no penetration was applied to all contacts in all articulations (25).…”

“…Six pairs of tibiofemoral contacts between the femoral cartilage and the meniscus, the meniscus and the tibial cartilage, and the femoral cartilage and the tibial cartilage were modeled for both the medial and lateral sides (25). A finite sliding frictionless hard contact algorithm with no penetration was applied to all contacts in all articulations (25). Convergence was defined as a relative change of >5% between two adjacent meshes.…”