Research Article - Biomedical Research (2019) Volume 30, Issue 1
Numerical study of stress shielding evaluation of hip implant stems coated with composite (carbon/PEEK) and polymeric (PEEK) coating materials.
The forces applied to the prosthesis during human activity produce dynamic stresses varying in time and may causing stress shielding in prosthesis-bone system. Therefore, it is important to reduce stress shielding effect. This study aimed to investigates, using finite element analysis, how a PEEK and carbon/PEEK composite coating materials on a titanium alloy hip implant stem could reduce stress shielding effect corresponding to different human activities: standing up, normal walking and climbing stairs under dynamic loadings to find out which of all these models have a better performance. A 3D finite element model of femur, hip implants, coating layers with composite (carbon/PEEK) and polymeric (PEEK) coating materials were constructed for finite element analysis. A time-dependent cycling load was applied on the prosthesis head. The maximum increase in load transfer to the bone was 207% for the prosthesis coated with carbon/PEEK configuration I (fibers orientated with 0, +45, -45, and 90 degrees) in average compared to uncoated one. Numerical result showed that the carbon/PEEK composite material (configuration I) seems to be a good solution to distribute the applied load and transfer it to the bone, thus to reduce stress shielding problems and to prolong lifetime of the prosthesis-bone system. It will prevent aseptic loosening and enhance the stability of the system.Author(s): Ayham Darwich, Hasan Nazha, William Abbas