Stress analysis of knee joint and knee prosthesis

Abstract

Knee joint consists of different components, i.e. femur, tibia, patella and menisci which make it a complex structure, undergoing different critical loads in human body performing motions and physical activities. The present study focuses on the analysis of stress magnitude on knee joint and knee implant when these are introduced with different loads acting upon it with varying angles of inclination. 3-D model of the knee joint and knee implant were designed using 3-D modeling softwarei.e. CAD. These models were imported to ANSYS to get the specific results of stress magnitude using finite element analysis. This study has revealedthat with a load range of 540N to 790 N and change in angle from 10° to 90°, the knee implant could be able to sustain a load of 540-640 N at an angle of 10°-50° demonstrating a stable stress value of 1.27E+08 – 6.11E+08 Pa. At steady state of the knee i.e. when the knee is at 90° position, stress value reaches to 1.28E+08 Pa. When this study was compared with stress analysis of the knee joint without implant it was observed that there is wide variation in the stress magnitude with the increase in load values and changing angles. At load of 690-790 N, the wearing effect become lesser at 10°, 70 ° and 90° angle. At an angle of 50°, stress value attains a high peak bar with 7.47E+08 Pa when 690 N load is applied on the knee joint without an implant. The study depicts that the load and stress can be better managed by the application of implant rather than without an implant. Hence the design of implant must give emphasis on different types of material depending upon the amount of stress experienced at different location. Overall, the study provides 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.