Using Design of Experiments Methods for Assessing Peak Contact Pressure to Material Properties of Soft Tissue in Human Knee.

Marjan Bahraminasab,Mahmoud Shamsborhan,Barkawi Sahari,Ali Jahan,Mohd Roshdi Hassan,Manohar Arumugam

doi:10.1155/2013/891759

Abstract

Contact pressure in the knee joint is a key element in the mechanisms of knee pain and osteoarthritis. Assessing the contact pressure in tibiofemoral joint is a challenging mechanical problem due to uncertainty in material properties. In this study, a sensitivity analysis of tibiofemoral peak contact pressure to the material properties of the soft tissue was carried out through fractional factorial and Box-Behnken designs. The cartilage was modeled as linear elastic material, and in addition to its elastic modulus, interaction effects of soft tissue material properties were added compared to previous research. The results indicated that elastic modulus of the cartilage is the most effective factor. Interaction effects of axial/radial modulus with elastic modulus of cartilage, circumferential and axial/radial moduli of meniscus were other influential factors. Furthermore this study showed how design of experiment methods can help designers to reduce the number of finite element analyses and to better interpret the results.

Highlights

Knee joint contact pressure is of critical importance in the mechanisms of knee pain and osteoarthritis [1, 2]
The adjusted R2 demonstrates that 95.8% of variation in peak contact pressure can be explained by Interaction plot for peak contact pressure (Mpa) 6.97 6.96 6.95 6.94 6.93 6.92 6.91 6.9 6.89 6.88
A sensitivity analysis of tibiofemoral peak contact pressure to the material properties of soft tissue was performed and design of experiments methods was used to reduce the number of program runs and to minimize the contact pressure error

Summary

Introduction

Knee joint contact pressure is of critical importance in the mechanisms of knee pain and osteoarthritis [1, 2]. Computational models and finite element analyses (FEA) have been utilized to study contact characteristics of normal and injured knees, as well as total knee replacements (TKR) [3,4,5,6,7,8] The purpose of these studies was to determine peak contact pressure in order to predict either tissue degradation of the knee or wear of ultra-high molecular weight polyethylene (UHMWPE) in TKR. Some biomechanical factors, such as material properties and geometries of tissues [9, 10], and knee kinematic [11] can affect the contact behavior of the knee and the design of TKR. In order to better interpret the effects of variations in the material properties of soft tissue, a powerful statistical approach is required to design computational experiments

Objectives

Methods

Results

Discussion

Conclusion