The treatment for end stage osteoarthritis of the knee is replacement of the natural joint with a total knee replacement prosthesis. A primary cause of failure of these devices is wear of the polyethylene tibial insert that acts as a bearing surface. While advances in materials science and engineering, as well as better implant designs, have led to a decrease in failures attributable to polyethylene wear, it remains a leading cause of long term failure of total knee replacements. Once a device has failed, it requires a revision procedure that can be both costly and risky for the patient. If total knee replacements are to last past the second decade, a better understanding of the factors that lead to wear is required. This is especially true once one considers the growing demand for total knee replacement surgeries, as well as the demographics of patients becoming younger.

Currently, wear of total knee replacements is investigated primarily using mechanical knee simulators. These devices, while required for preclinical testing, are limited in their ability to investigate a large number of parameters due to the time and cost associated with running them. Computer modeling, in particular finite element analysis and analytical wear modeling, offers a way to perform large scale parametric studies of total knee replacement wear as a complementary tool to mechanical testing.

In this dissertation, a computational workflow is developed using a frictional energy based model of polyethylene wear coupled to a finite element model of a total knee replacement. This model is validated against multiple mechanical tests. The computational workflow is capable of investigating many of the factors that may be contributors to polyethylene wear in a total knee replacement, including surgical component alignment and patient specific kinematic and loading parameters.

The utility of the model is first demonstrated by comparing two versions of the International Standards Organization standard for displacement controlled wear testing of total knee replacements. Using the computational model, it is demonstrated that differences in total volumetric wear and distribution of wear exist between the version of the standard released in 2004 and the version released in 2014. This finding serves as a caution to researchers and regulatory entities that comparisons between results that used different versions of the standard should be approached with caution.

The computational workflow was utilized to investigate the influence on wear of several component alignment factors. It was demonstrated that component alignment can have a large impact on wear, and in particular, proper alignment of the internal/external rotation of the components is critical. The workflow was further utilized to study the effects of kinematics and loading on wear. Using modified inputs from a standard wear testing protocol, it was demonstrated that flexion/extension pattern, and not loading as may be expected, has the highest effect on wear in a total knee replacement. This method was also applied to the average walking gait of a patient population, where the focus was on secondary motions. It was demonstrated that wear is most affected by anterior/posterior translation and internal/external rotation during the end of stance phase.

In conclusion, the tools developed throughout the course of this project enable researchers and designers to conduct large scale and comprehensive analyses of the various factors that contribute to wear in total knee replacements. These tools were utilized in several studies and led to a greater understanding of the factors that contribute to wear of polyethylene in total knee replacements.