Author: Haoqian Qian
Qian, Haoqian, 2019 Finite element analysis of implanted proximal tibia, Flinders University, College of Science and Engineering
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Despite the poor initial stability of the cementless fixation, the osteointegration of an uncemented knee replacement is still the ultimate destination of a desired total knee replacement solution for knee osteoarthritis (OA) at the moment. To achieve bone ingrowth onto the implants, micromotion has been an inevitable parameter to interrogate in the study of knee implant primary stability. Considering that the complexity of the contact issues, coupled with uncemented fixation, could result in different magnitude of micromotion or micromotion patterns, we can have a hypothesis that such surface morphological parameters as flatness is likely to have an effect on micromotion. Therefore, the aim of this thesis is to incorporate the uneven surgical tibial cut into the finite element models and try to find out the effect of flatness of the surgical cut on micromotion at the tibial-bone interface. This study generates finite element models from nine surgical resected proximal tibiae and a commercial available tibial tray design from DePuy, and simulates loadings from level gait to examine the effect of flatness on the micromotion between the implant and the bone. What is found is that the flatness of the resected proximal tibia is moderately correlated with the peak micromotion at the interface during level gait. Moreover, the peak micromotion occurs at minimal ML loads, moderate axial loads, AP loads and FE moment but maximal IE moment and minimal VV moment in one cycle. Finally, loadings have a more dominant effect on when the micromotion occurs, while surface morphology is likely to have a more dominant effect on where the micromotion occurs and its corresponding magnitude in an uneven surface. This brings flatness as a variable to consider into the finite element model and the needs to also explore more activities, implant designs, cycles, sample groups to further investigate the relationship between the flatness of the surgically resected surface and the micromotion at the interface of the implant and the bone.
Keywords: cementless, knee replacement, finite element analysis, flatness, micromotion
Subject: Health Sciences thesis
Thesis type: Masters
Completed: 2019
School: College of Science and Engineering
Supervisor: Mark Taylor