Impact of different dosages of e-beam irradiation on mechanical strength of vitamin E-blended ultra-high-molecular-weight polyethylene and the osteolytic activities of its wear debris

Global medical implant manufacturing has been extensively focused on the development of materials with high mechanical strength, fatigue resistance and reduced biologically osteolytic activity in vivo. Electron beam (e-beam) irradiation has been widely used for creating a highly crosslinked vitamin E blended UHMWPE. Here, we evaluated the mechanical properties of VE-UHMWPE irradiated by e-beam with dosages of 150 and 300 kGy, and the biological responses to the material wear debris. Oxidation index values for VE-UHMWPE irradiated by 300 kGy were significantly higher than these irradiated by 150 kGy. Although VE-UHMWPE irradiated by 300 kGy exhibited significantly reduced values of the impact strength values and elongation as compared to these irradiated by 150 kG, wear productions in hip simulator test were comparable in both types of VE-UHMWPE. Furthermore, both types of VE-UHMWPE particles induced comparable inflammatory responses and osteolytic activities in vitro and in vivo. The better mechanical properties of 150-irradiated VE-UHMWPE suggest that this dosage is appropriate for crosslinking UHMWPE material of the prostheses.