Bone remodelling around uncemented metallic and ceramic acetabular components

Abstract

Stress shielding-induced bone resorption around cementless acetabular components has been indicated as a potential failure mechanism that may threaten long-term fixation. Using a bone remodelling algorithm in combination with threedimensional finite element models of intact and implanted pelvises and musculoskeletal loading during normal walking, the objectives of the study were to investigate the deviations in load transfer due to implantation and bone adaptation around cementless metallic and ceramic acetabular components. Variations in implant-bone interfacial condition affected strain shielding and bone remodelling; strain shielding was higher for the bonded condition as compared to the debonded condition. For bonded interfacial condition, severe bone resorption, 20%-50% bone density reduction, was observed within the acetabulum. Considering debonded implant-bone interface, bone density increase of 50%-60% was observed around the supero-posterior part of acetabulum, whereas bone density reductions were low (2%-15%) in other locations. The implant-bone interface appeared less likely to fail, post-operatively and after bone remodelling. Moreover, the implant-bone micromotion was found to be low, less than 100 mm. Strain shielding and bone remodelling were almost similar for the metallic and ceramic components. Based on the results of this study, the ceramic acetabular component appeared to be a viable alternative to metal.

Towards the optimal design of an uncemented acetabular component using genetic algorithms

“…Three-dimensional FE models of the intact and implanted pelvises were generated from data from computed tomography (CT) scans of a 62-year-old female patient, similarly to an earlier study (Ghosh, Mukherjee, and Gupta 2013;Ghosh et al 2013b). The generation procedure of the FE model was verified and experimentally validated (Ghosh et al 2012(Ghosh et al , 2013a.…”

“…An augmented Lagrange contact algorithm was used for the contact simulation between the femoral head and the acetabular component. The effects of variable implant-bone interface conditions on bone remodelling around uncemented metallic and ceramic acetabular components were investigated by Ghosh, Mukherjee, and Gupta (2013), who observed that the decrease in bone density was maximum for the fully bonded implant-bone interface condition. Accordingly, the fully bonded interface condition was assumed between the bone and implant.…”

“…Thereafter, the hip joint force was resolved along three orthogonal directions in the FE coordinate system and applied through the centre of the femoral heads (intact and implanted). Some fixed constraints were prescribed at the pubic symphysis and the sacroiliac joint (Dalstra and Huiskes 1995;Ghosh, Mukherjee, and Gupta 2013). A submodelling technique, similar to the previous study (Ghosh, Mukherjee, and Gupta 2013) was employed, wherein displacements at the cut boundaries in the submodel were transferred from the corresponding full model of the implanted pelvis ( Figure 1).…”

“…Employing hard-on-hard bearing surfaces, such as metal-on-metal, ceramic-on-ceramic and metal-on-ceramic, reduces wear but increases peri-prosthetic bone resorption (Wilkinson et al 2001;Laursen, Nielsen, and Soballe 2007;Ghosh, Mukherjee, and Gupta 2013). On the other hand, using a polyethylene acetabular cup leads to minimal changes in bone density but excessive generation of wear debris (Harris 1995).…”

Activity intensity, assistive devices and joint replacement influence predicted remodelling in the proximal femur

“…A mechanostat principle was applied, based upon the strain history stimulus required to produce a bone volume change (Carter 1984), and implemented using Euler forward integration to calculate iterative changes in the thickness of cortex elements (external remodelling), or the heterogeneous density-and hence the Young's modulus-of trabecular elements (internal remodelling). This method has been applied to femoral implants in THR (Kerner et al 1999;Turner et al 2005), RHR (Gupta et al 2006;Pal et al 2009;Rothstock et al 2011;Dickinson et al 2012;Perez et al 2014), to acetabular cups (Ghosh et al 2013), and in other joints (van Lenthe et al 1997). Advanced approaches have combined strain adaptive bone remodelling with other associated mechanobiological processes, including cementless implant ingrowth (Tarala et al 2011) and periprosthetic defect healing (Dickinson et al 2012).…”