Wear Outcomes of a Metal on Metal Disc Arthroplasty – A Computational Model

Earlier efforts in areas of hip and knee arthroplasties suggest that wear debris, could initiate inflammatory responses leading to peri-prosthetic osteolysis and bone resorption at the implant-bone interface. Aseptic loosening of implants due to particle induced osteolysis is the primary cause of revision surgeries. Bench top wear tests as well as bioreactivity studies have emerged as a powerful preclinical tool. However there is still a gap between the in vitro bench-top wear tests and the retrieval test cases. Predict ive fin ite element modeling based on wear-laws serve as an excellent design tool for parametric analyses. In such models, the effect of individual variables can be judged independently leading to an understanding of the role of that parameter on the final outcome. Comparative wear data for art ificial cervical discs are sparse. The purpose of this study is to characterize the wear performance of a metal-on-metal (MOM) ball and trough artificial d isc and compare the wear performance of this device to metal-on-polymer (MOP) ball-on-trough artificial disc in an in-v itro and in-vivo simulation using FE modeling. Our hypothesis is that wear rates and patterns in an in-vivo scenario d iffers from machine simulated data and is also dependent on the material combination chosen.