Finite Element Simulations of Hard-On-Soft Hip Joint Prosthesis Accounting for Dynamic Loads Calculated from a Musculoskeletal Model during Walking

Abstract

The hip joint replacement is one of the most successful orthopedic surgical procedures although it involves challenges to overcome. The patient group undergoing total hip arthroplasty now includes younger and more active patients who require a broad range of motion and a longer service lifetime for the replacement joint. It is well known that wear tests have a long duration and they are very expensive, thus studying the effects of geometry, loading, or alignment perturbations may be performed by Finite Element Analysis. The aim of the study was to evaluate total deformation and stress intensity on ultra-high molecular weight polyethylene liner coupled with hard material head during one step. Moving toward in-silico wear assessment of implants, in the presented simulations we used a musculoskeletal multibody model of a human body giving the loading and relative kinematic of the investigated tribo-system during the gait. The analysis compared two frictional conditions -dry and wet and two geometrical cases- with and without radial clearance. The loads and rotations followed the variability of the gait cycle as well as stress/strain acting in the UHWMPE cup. The obtained results allowed collection of the complete stress/strain description of the polyethylene cup during the gait and calculation of the maximum contact pressure on the lateral edge of the insert. The tensional state resulted in being more influenced by the geometrical conditions in terms of radial clearance than by the variation of the friction coefficients due to lubrication phenomena.

A Critical Analysis of TKR In Vitro Wear Tests Considering Predicted Knee Joint Loads

“…These studies also point out that different people, with similar weight and height, show different load configurations due to their different ways to run specific movements. From a clinical point of view, given the high variability of loads, direct measurement of joint reaction forces is generally not feasible in a clinical setting; there is a great interest to develop a new in silico approach, based on musculoskeletal modelling [39], in order to assess the loads acting on the knee joint and define which loads are appropriate for mechanical tests of TKR. The results of this study might provide advantages from a tribological point of view; we investigated the ability of a multibody model to effectively predict knee joint forces for in vitro wear tests.…”

Editorial: Biotribology and Biotribocorrosion Properties of Implantable Biomaterials

“…Considering the above, to date, in-silico wear prediction models of artificial human implants attract the attentions of researchers to obtain complete tribological theoretical and numerical models useful for the in-silico testing (O'Brien et al, 2015;Mattei et al, 2016;Affatato et al, 2018), which could avoid the standard in-vitro time-consuming investigation procedures (simulators) and could contribute as tool for a more and more accurate tribological design of human prostheses. Obviously, the accurate wear prediction of artificial joints requires to develop detailed tribological models accounting for the complexity and the multiscale of wear phenomenon (Vakis et al, 2018) which requires scientific knowledge in many fields, such as contact mechanics (Popov, 2010), topographic contact surfaces characterization (Merola et al, 2016), new materials formulations (Affatato et al, 2015), stress-strain analysis and FEM/BEM simulations (Ruggiero et al, 2018;Ruggiero and D'Amato R, 2019), musculoskeletal multibody modeling (Zhang et al, 2017), unsteady synovial lubrication modeling (boundary/mixed, hydro-dynamic and EHD) (Ruggiero and Sicilia, 2020), tribo-corrosion (Tan et al, 2016), metal transfer phenomena (Affatato et al, 2017), biomaterials characterizations (Ruggiero et al, 2016), etc. Moreover, innovative biomaterials and manufacturing procedures (e.g., 3D printing), novel surface modification (coatings) constitute new and exciting research areas (Ten Kate et al, 2017).…”

A Perspective on Biotribology in Arthroplasty: From In Vitro toward the Accurate In Silico Wear Prediction

“…The experimental tribological devices for the simulation of hip and knee prostheses have been improved over the years in order to make them able to reproduce tribological wear tests in kinematic and dynamic conditions very close to the real ones [30][31][32][33]. The new trend of an in silico approach to the evaluation of the articular prostheses' wear represents, nowadays, a fascinating scientific challenge, which involves many disciplinary fields and which requires a deep collaboration between scientists from different areas [41][42][43][44].…”

“…O'Brien et al proposed an interesting theory based on energy dissipation: the process of wear is inherently dynamically adaptive, and localized high wear can result in faster deformation in The in silico procedure starts by evaluating the human motion kinematics in the framework of inverse dynamic analysis (motion capture) with reference both to normal gait and other desired daily activities [32,45]. The obtained data are used for the calculation of the unsteady joint forces which are used as load conditions in joint Finite Element Analysis (FEM) [42][43][44]. The resulting stress-strain behavior of the artificial coupling have to be joined with the lubrication model for taking into account the complex synovial phenomena acting in the joint [41,46].…”