Calculation of the elastic properties of prosthetic knee components with an iterative finite element-based modal analysis: quantitative comparison of different measuring techniques

Abstract

Abstract:With the aging but still active population, research on total joint replacements relies increasingly on numerical methods, such as finite element analysis, to improve wear resistance of components. However, the validity of finite element models largely depends on the accuracy of their material behavior and geometrical representation. In particular, material properties are often based on manufacturer data or literature reports, but can alternatively be estimated by matching experimental measurements and structural predictions through modal analyses and identification of eigenfrequencies. The aim of the present study was to compare the accuracy of common setups used for estimating the eigenfrequencies of typical components often used in prosthetized joints. Eigenfrequencies of cobalt-chrome and ultra-high-molecular weight polyethylene components were therefore measured with four different setups, and used in modal analyses of corresponding finite element models for an iterative adjustment of their material properties. Results show that for the low-damped cobalt chromium endoprosthesis components, all common measuring setups provided accurate measurements. In the case of high-damped structures, measurements were only possible with setups including a continuously excitation system such as electrodynamic shakers. This study demonstrates that the iterative backcalculation of eigenfrequencies can be a reliable method to estimate the elastic properties for finite element models.

Posterior cruciate ligament balancing in total knee arthroplasty: a numerical study with a dynamic force controlled knee model

“…Linear elastic material properties were defined for the prosthesis after they had been verified in a former study [19]. Also, the unresurfaced patella cartilage was considered to behave linear elastically which was described by Pena et al [14] (Table  1A).…”

TKA design-integrated trochlea groove rotation reduces patellofemoral pressure

“…This model was validated with an experimental weight‐bearing knee rig in a former study and, therefore, is described here only briefly [56]. A further validation step, described in Woiczinski et al, was completed to verify the material properties of the TKA components used in this in silico model [57].…”