0
Research Papers

Experimental Validation of a Finite Element Model of a Human Cadaveric Tibia

[+] Author and Article Information
Hans A. Gray

Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, UKhans.gray@stcatz.oxon.org

Fulvia Taddei

Laboratorio di Tecnologia Medica, Istituti Ortopedici Rizzoli, Via di Barbiano 1/10, 40136 Bologna, Italytaddei@tecno.ior.it

Amy B. Zavatsky

Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, UKamy.zavatsky@eng.ox.ac.uk

Luca Cristofolini

DIEM, Engineering Faculty, University of Bologna, Viale Risorgimento 2, 40136 Bologna, Italy; Laboratorio di Tecnologia Medica, Istituti Ortopedici Rizzoli, Via di Barbiano 1/10, 40136 Bologna, Italyluca.cristofolini@unibo.it

Harinderjit S Gill

Nuffield Department of Orthopaedic Surgery, University of Oxford, Nuffield Orthopaedic Centre NHS Trust, Oxford OX3 7LD, UKrichie.gill@ndos.ox.ac.uk

J Biomech Eng 130(3), 031016 (May 01, 2008) (9 pages) doi:10.1115/1.2913335 History: Received April 26, 2007; Revised April 02, 2008; Published May 01, 2008

Finite element (FE) models of long bones are widely used to analyze implant designs. Experimental validation has been used to examine the accuracy of FE models of cadaveric femurs; however, although convergence tests have been carried out, no FE models of an intact and implanted human cadaveric tibia have been validated using a range of experimental loading conditions. The aim of the current study was to create FE models of a human cadaveric tibia, both intact and implanted with a unicompartmental knee replacement, and to validate the models against results obtained from a comprehensive set of experiments. Seventeen strain rosettes were attached to a human cadaveric tibia. Surface strains and displacements were measured under 17 loading conditions, which consisted of axial, torsional, and bending loads. The tibia was tested both before and after implantation of the knee replacement. FE models were created based on computed tomography (CT) scans of the cadaveric tibia. The models consisted of ten-node tetrahedral elements and used 600 material properties derived from the CT scans. The experiments were simulated on the models and the results compared to experimental results. Experimental strain measurements were highly repeatable and the measured stiffnesses compared well to published results. For the intact tibia under axial loading, the regression line through a plot of strains predicted by the FE model versus experimentally measured strains had a slope of 1.15, an intercept of 5.5 microstrain, and an R2 value of 0.98. For the implanted tibia, the comparable regression line had a slope of 1.25, an intercept of 12.3 microstrain, and an R2 value of 0.97. The root mean square errors were 6.0% and 8.8% for the intact and implanted models under axial loads, respectively. The model produced by the current study provides a tool for simulating mechanical test conditions on a human tibia. This has considerable value in reducing the costs of physical testing by pre-selecting the most appropriate test conditions or most favorable prosthetic designs for final mechanical testing. It can also be used to gain insight into the results of physical testing, by allowing the prediction of those variables difficult or impossible to measure directly.

FIGURES IN THIS ARTICLE
<>
Copyright © 2008 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 1

Anterior, lateral, posterior, and medial views of strain rosette attachments on the tibia. Level 1 is proximal and Level 4 is at mid-diaphysis. A=anterior, P=posterior, M=medial, L=lateral.

Grahic Jump Location
Figure 2

Transverse view of proximal end of the tibia showing the nine points at which the 300N axial load was applied. The first letter of each label indicates the condyle, and the second letter the location within the condyle: A=anterior, P=posterior, M=medial, L=lateral, C=central.

Grahic Jump Location
Figure 3

Experimental setup for torsional loading with enlarged view of proximal pot assembly. The distal pot was rigidly fixed on the load transducer (not shown), which was fixed on the testing machine. The proximal end was twisted through the crosshead, a sliding joint, and a cross (universal) joint.

Grahic Jump Location
Figure 4

The distribution of axial Young’s modulus along the tibia. Each point represents an element

Grahic Jump Location
Figure 5

The intact cadaveric tibia FE model together with the boundary conditions used to simulate four-point bending in the mediolateral direction

Grahic Jump Location
Figure 6

FE model principal strains plotted against experimental principal strains for all nine axial load cases combined, along with the best fit regression line for the intact cadaveric tibia

Grahic Jump Location
Figure 7

FE model principal strains plotted against experimental principal strains for all five axial load cases combined, along with the best fit regression line for the implanted cadaveric tibia

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In