The Effect of Different Material Combinations on Wear of an Artificial Cervical Disc as Standalone vs. Placed in a Ligamentous Motion Segment

Earlier efforts in areas of hip and knee arthroplasties suggest that wear debris, especially from polymeric components, 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. Metal based implants are considered superior in terms of wear resistance.^1–2 However metal-on-metal articulation leads to much smaller sized particulates in comparison to metal-on-polymers. Thus for an equal volume of wear debris from both polymer and metal, the number of metallic particulates can be up to 100 times greater³. Accumulation of metallic debris in the periprosthetic tissue leads to the formation of a fibrous membrane, which might act as a channel for polymeric particulates⁴. 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. Additionally, these experiments are time consuming, expensive, and labor-intensive procedures. In spite of the fact that experimental data are indispensable, alternatives need to be explored. Predictive finite 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.