Animal Model Of Infection After Total Knee Arthroplasty

Objectives To establish the animal model of total knee arthroplasty and to evaluate the value of application.Methods 54 new Zealand male rabbits weighing 3.0-3.5 kg were randomly divided into three groups in this study: the control group(n=18),the model group(n=18), the arthroplasty uninfection group(n=18). The swanson flexible hinge toe implants were used for knee prothesises.After 3 days of operation, 105 cfu of a clinical strain of methicillin-susuceptible staphylococcus aureus( MSSA) was injected into the operated knee in the model group,the rabbit in the arthroplasty uninfection group were injected the sterile saline. X ray, 3.0T MRI,18F-FDG-PET,WBC, C Reactive Protein, Erythrocyte Sedimentation Rate,pathological examination and microbiologic studies were performed on 1st and 3rd week after surgery.Results 88.8%(16/18) survival rate after 3 days of operation was achieved;Magnetic resonance imaging show evidence of prosthetic infection;There is periprosthetic activity present on 18F-FDG of the operated knee in the arthroplasty infection group, There was statistical significances for operated-to-normal-knee activity ratios(ONKR) between the model group and the arthroplasty uninfection group after 3 days of operation(P<0.05);The level of WBC and Erythrocyte Sedimentation Rate were statistical significances in the arthroplasty infection group compared with the control group after 1st and 3rd week of operation(P<0.05),There was statistical significances for the level of WBC between the model group and the arthroplasty uninfection group after 3 days of operation(P<0.05);Histological examination show abscess formation and scattered poly-morphonuclear leukocyte infiltration were present inside the joint.Cultures of all samples from the model group and 2 samples from the arthroplasty uninfection group were septic.Conclusion This method can produces prosthetic infection models that is effective,reproducible and close to the situation of human prosthetic infection.