Effect of Geometric Parameters in the Design of Hip Implants Paper IV

The effect of geometric parameters has been studied in this paper on the development of stress in hip implants. The parameters include: head diameter, neck diameter, and neck angle. Two three-dimensional models were drawn, one modular and one integrated implant. These models were then altered geometrically one variable at a time, and finite element analysis (FEA) was performed on the models. In total, twenty assemblies of implant/bone cement/bone were tested. Stress spectrum was drawn for each case under a combination of hip dimensions. It is shown that as the head diameter increases, the stress at a given location reduces, however, as the surface area from increased head diameter increases, the wear rate increases. Neck angle has been found to concentrate stresses in the select regions of the hip implant. In that an angle of 40° showed low stress combinations. Therefore, a particular combination offering the best performance has not been identified and constitutes a part of an on going research activity in Mechanical Engineering Department at Ohio Northern University.