Changing the Mechanical Properties of PMMA Bone Cement with Nano and Micro Particles

Total joint arthroplasty is a highly successful way to restore pain free function to patients afflicted with arthritis. Poly(methylmethacrylate) (PMMA) bone cement is commonly used as a fixing agent in artificial joints. The historical success rate on patients over 60 years (in a ten year time frame) exceeds 90%. Loosening is often preceded by the fracture of the bone cement, which will inevitably lead to a prosthesis failure and require a revision surgery. Bone cement used for total joint surgeries has not changed significantly since first introduced in the 1960's. This research seeks to improve the fracture resistance of bone cement by introducing changes in the fundamental microstructure of the cement, thus increasing the fracture resistance of bone cement and the life of the artificial joint. Novel cements were created by replacing a percentage (10%) of the solid phase using 4 different additives. Fracture toughness tests were performed as the primary indicator of improved mechanical performance. The cross-linked additives showed an increase of 33% when compared to the fracture toughness of the control group. Scanning Electron Microscope (SEM) imaging and nanoindentation were used to further characterize the properties of the new bone cements. This research suggests that the fracture properties of existing bone cement may be improved by microstructural changes. Such changes may eliminate or reduce bone cement failure and thereby prevent prosthesis failures that require costly revision surgeries. The ultimate outcome of this research is to improve the quality of life for people with arthritis