Finite Element Optimization of Hip Implant Geometrical Parameters to Determine Safe Zones and Resist Dislocation
Tarun Goswami (Advisor), S. Narayanan (Committee Member), David Reynolds (Committee Member)
Master of Science in Engineering (MSEgr)
A computational study was performed using finite element analysis (FEA) of three dimensional solid hip implant models. Twelve different hip implant models were designed to investigate the performance of geometrical parameters affecting hip stability. The parameters examined were head diameter, neck diameter, head-to-neck ratio, neck angle and acetabular liner thickness. Component orientations included cup anatomical inclination and cup anteversion, which should be accounted for during total hip implant design as well as in the practice of arthroplasties. A static analysis was performed for all 12 hip designs using stainless steel 316L. von Mises stress, contact stress, contact penetration, and sliding displacement were correlated with the geometrical parameters as well as with anatomical orientations of acetabular component.
Analytical results were used to define safe zones for a combination of geometrical parameters that provided maximum hip stability. Head diameters from 26 mm to 32 mm were found within safe ranges. Lower head diameters showed comparatively higher contact penetration increasing risk of dislocation in vivo. The preeminent stress results were found with combinations of 26 mm head and 14 mm neck diameters with 35 degrees of neck angle. Lower cup anatomical inclination tends to provide higher contact surface with femoral head during articulations developing lower contact stresses. The safe combination for cup orientation was observed with cup anatomical inclinations ranging from 35 to 50 degrees and cup anteversion below 20 degrees. New generic and specific equations were developed using the data from FE analysis to predict penetration. Evaluated penetration can then be used to determine the linear wear rate (in vivo).
Department or Program
Department of Biomedical, Industrial & Human Factors Engineering
Year Degree Awarded
Copyright 2008, all rights reserved. This open access ETD is published by Wright State University and OhioLINK.