Methods

Study groups: 1). Radiation cross-linked VE-UHMWPE, 0.8% by weight, diffused after 100 kGy; 2). Radiation cross-linked virgin UHMWPE (virgin UHMWPE); 3). Shams. Particle generation and implantation: UHMWPE was sent to Bioengineering Solutions for particle generation. After IACUC approval, C57BL/6 mice (n = 12 for each group) received 3 mg of particulate debris overlying the calvarium and euthanized after 10 days. Micro-CT scans: Performed using an X-Tek-HMX-ST-225 with 70 kV voltage and 70 μA current. Topographical Grading Scale: Each calvarial bone was blindly scored with the following scale: 0 = No osteolysis, defined as intact bone; 1 = Minimal osteolysis, affecting 1/3 or less of the bone area; 2 = Moderate osteolysis, affecting at least 2/3 of the bone area; 3 = Severe osteolysis, defined as completely osteolytic bone. Histology H&E and TRAP staining was performed. Statistical Analysis: Inter-rater analysis was performed using Cohen's kappa analysis. Inter-rater coefficient >0.65 was considered as high inter-rater agreement. Comparison between groups was made using one-way ANOVA with post hoc Bonferroni correction for multiple comparisons. Correlations are reported as Spearman's rho. A p-value<0.05 was considered statistically significant.