Biomechanical comparison of fixed‐ and mobile‐bearing for unicomparmental knee arthroplasty using finite element analysis

Abstract

Unicomparmental knee arthroplasty (UKA) is a popular alternative to total knee arthroplasty (TKA) and high tibial osteotomy for unicompartmental knee conditions, especially in young patients. However, failure of UKA occurs due to either progressive osteoarthritis (OA) in the other compartment or wear on the polyethylene (PE) insert. This study used finite element (FE) analysis to investigate the effects of PE insert contact pressure and stress in opposite compartments for fixed-and mobile-bearing UKA. Analysis was performed using high kinematics displacement and rotation inputs, which were based on the kinematics of the natural knee. ISO standards were used for axial load and flexion. The mobile-bearing PE insert had lower contact pressure than the fixed-bearing PE insert. With the mobile-bearing UKA, lower stress on the opposite compartment reduces the overall risk of progressive OA in the knee. The fixed-bearing UKA increases the overall risk of progressive OA in the knee due to higher stress on the opposite compartment. However, the PE insert of mobile-bearing showed pronounced backside stress at the inferior surface. ß

Probabilistic Approach for Determining the Material Properties of Meniscal AttachmentsIn VivoUsing Magnetic Resonance Imaging and a Finite Element Model

“…Specifically, we believe that our results will be useful not only for establishing diagnoses, but also for surgery in allowing for evaluation of the material properties of a patient's soft tissue in vivo using MRI. In many previous computational studies, MR images have been primarily used to generate intact FE models, followed by validation in cadavers (Haut Donahue et al, 2003;2004;Pena et al, 2006;Baldwin et al, 2009;Dhaher et al, 2010;Kwon et al, 2014). However, we hypothesize that data from evaluation of material properties in vivo using MR images will be useful for both damaged and normal knees.…”

“…Briefly, the FE models were imported into Hypermesh (version 8.0; Altair Engineering, Inc., Troy, MI) to generate an enhanced FE mesh that was subsequently analyzed with ABAQUS software (version 6.11; Simulia, Providence, RI). Rigid structured bone models had minimal influence in this study due to the decreased stiffness compared to relevant soft tissues (Pena et al, 2006;Kwon et al, 2014). Subject-specific FE models of the soft tissue included articular cartilage, all eight of the major ligaments, the menisci, and the menisci horn attachments.…”

“…4). Subject-specific FE models were created according to the method introduced in a previous study (Kwon et al, 2014). Briefly, the FE models were imported into Hypermesh (version 8.0; Altair Engineering, Inc., Troy, MI) to generate an enhanced FE mesh that was subsequently analyzed with ABAQUS software (version 6.11; Simulia, Providence, RI).…”

In vivo evaluation of the subject-specific finite element model for knee joint cartilage contact area

“…Most of these models lack validation or verification against data from the same subjects. [4][5][6][7][8] The purpose of the present study was to apply easily adaptable validation methods to study the ability of a subject-specific FE model to reproduce close to the in vivo loading condition using the subject's own data. Verification was conducted by comparing the results from the model with either literature data or in vitro cadaveric data.…”

“…4 Most of these studies have been validated or verified with published cadaveric testing references followed by in vivo FE modeling. [5][6][7][8] Furthermore, a method of subject-specific modeling has been introduced using MRI data from cadavers, validated using subject-specific cadaver testing. 9 Validation or verification is a crucial step before interpreting model predictions or using the model for clinical applications.…”