3D MODELLING AND FINITE ELEMENT ANALYSIS OF KNEE JOINT USING COMPUTED TOMOGRAPHY (CT) DATA

Abstract

Knee joint consists of different components, tibia, femur, patella, ligaments, menisci and tendons. They make it one of the most complicated structures, experiencing different critical loads in human body along with movement, locomotion and performing physical activities. Present study focuses on the analysis of maximum principal stress, Maximum principal elastic strain and total deformation on knee joint when for various loads applied on it with different boundary conditions. The idea is to first of all present a graphical modeling methodology of human anatomical constructs like the bones, the tibia, the femur and the patella. Secondly, it involves performing a FE analysis of the human knee joint under static loading conditions. The 3-D CAD model of the human knee joint is generated by the use of CT images transformed into geometric model with the help of Simpleware ScanIP. The models are then imported to ANSYS 15.0 to obtain the results of the stress magnitude by finite element analysis. A study of load range of 540N to 790 N at standing position and at flexion angle of 900 is carried out. The mechanical properties like Poisson’s Ratio and Young’s Modulus of the human bones differ from individual to individual, usually according to age, weight and gender. The most important purpose of FEA (Finite Element Analysis) in orthopedic biomechanics is to predict and understand the mechanical nature of bones, develop design of implants with improvement, and eliminate/minimize the cost and time required in vivo and in vitro experimentation. Finite Element modeling is also used for bone remodeling and healing phenomena of conventional and biomimetic devices, such as hip replacements. Of late, computational modeling along with bone biology, biochemistry, and thermodynamics is being used to create new therapeutic strategies related to bone loss and other bone related diseases. The study helps in the design of implant by giving emphasis on different types of material to be used depending upon the amount of stress experienced at different locations in knee joint. Overall, the study provides a relation in the stress magnitude in different components of knee joint and will be helpful in providing a guideline for fabrication of prosthetic implant in the line of intimation with reduced number of experiments so that implants with better stress management and enhanced load bearing capacity can be designed.