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

Abstract

Bone morphology and density changes are commonly observed following joint replacement, and may contribute to the risks of implant loosening and periprosthetic fracture, and reduce the available bone stock for revision surgery. This study was presented in the "Bone and Cartilage Mechanobiology across the scales" WCCM symposium to review the development of remodelling prediction methods and to demonstrate simulation of adaptive bone remodelling around hip replacement femoral components, incorporating intrinsic (prosthesis) and extrinsic (activity and loading) factors.An iterative bone remodelling process was applied to finite element models of a femur implanted with a cementless THR (total hip replacement) and a hip resurfacing implant. Previously developed for a cemented THR implant, this modified process enabled the influence of pre-to postoperative changes in patient activity and joint loading to be evaluated. A control algorithm used identical pre-and postoperative conditions, and the predicted extents and temporal trends of remodelling were measured by generating virtual x-rays and DXA scans.The modified process improved qualitative and quantitative remodelling predictions for both the cementless THR and resurfacing implants, but demonstrated the sensitivity to DXA scan region definition and appropriate implant-bone position and sizing. Predicted remodelling in the intact femur in response to changed activity and loading demonstrated that in this simplified model, although the influence of the extrinsic effects were important, the mechanics of implantation were dominant. This study supports the application of predictive bone remodelling as one element in the range of physical and computational studies, which should be conducted in the pre-clinical evaluation of new prostheses.

Does a PEEK Femoral TKA Implant Preserve Intact Femoral Surface Strains Compared With CoCr? A Preliminary Laboratory Study

“…There are established theories that bone’s mechanical adaptation stimulus is related to the strain it experiences [ 7 ]. Numerical modeling and in vitro experimental work has indicated general correspondence between the change in the bone strain field after implantation and the progressive remodeling changes observed in clinical measurements [ 3 , 5 , 27 , 32 ]. Digital image correlation (DIC) is a noncontact image analysis technique increasingly used in biomechanics for full-field strain assessment of complex three-dimensional surface geometry, including heterogeneous, anisotropic materials such as bone tissue [ 24 ].…”

Foreword to the special issue on Bone and cartilage mechanobiology across the scales

“…The first paper in this series deals with the development of a computational modeling tool, which allows to better understand and control the growth process of in vitro cultured neotissues toward obtaining functional tissues (Guyot et al 2015). The second paper on orthopedics deals with finite-element simulations of the bone remodeling process of a femur implanted with a cementless total hip replacement and a hip resurfacing implant (Dickinson 2015). This study supports the application of predictive bone remodeling algorithms as one element in the range of physical and computational studies, which should be conducted in the preclinical evaluation of new prostheses.…”