Aseptic loosening from polyethylene wear debris is the leading cause of failure for metal-on-polyethylene total hip implants. Outlier implant patients also experience increased wear compared to the general patient population. Third body debris ingress into the joint is one suspected culprit because it results in roughening of the metal femoral head, increasing wear. To study the effect of third body debris on total hip implant wear, a hip implant finite element model was used to calculate wear for in vivo total hip use under nonroughened and roughened femoral head conditions. Femoral head roughening locations were parametrically varied to determine the locations of roughening on the femoral head that result in maximal wear. With these most critical regions of femoral head roughening known, a computational model was developed to find the areas on the polyethylene acetabular cup articular surface where if debris were embedded, could roughen the femoral head in the critical regions. Also investigated with the finite element model were the effect of implant parameters and alternate activities of daily living on wear. It is hypothesized that ingress of third body debris is facilitated by fluid transport during hip subluxation. The manner by which third bodies gain access to the joint was investigated by the development and parametric exercise of a 3D computational fluid dynamics model of total hip subluxation. A study of retrieved total hip implants to determine the relationship between impingement damage (suggesting subluxation/dislocation) and embedded debris (indicating third body ingress) was undertaken to corroborate computational fluid dynamics model findings.