Antibacterial Activity And Drug Concentrationg Monitoring Of Joint Fluid In Primary Total-Knee Arthroplasty

Objective To Evaluate the antibacterial activities and drug concentration monitoring of joint fluids of patients undergoing primary total-knee arthroplasty(TKA)and compare the differences between bone cement loaded with 0.5g vancomycin and that loaded with 1g vancomycin on drug concentration and antibacterial activites.Methods Thirty patients who were scheduled for primary cemented TKA were enrolled in the study.The patients were grouped on the basis of the cement loaded with 0.5g vancomycin and 1g vancomycin.The former is control group,the latter is treatment group.Cefuroxime was administered to every patient as the perioperative prophylactic antibiotic.Samples of joint fluids were collected from the knee joints at 8,16,24,32,40,and 48 h after prosthesis implantation.We assessed the bioactivities of the joint fluids against methicillin-susceptible Staphylococcus aureus(MSSA)and methicillinresistant S.aureus(MRSA).The antibiotic contents of the joint fluid samples were further evaluated by using high-performance liquid chromatography.Results Against MSSA,all antibiotics exhibited significantly bacterial inbibition activity.However,antibacterial activity against MRSA was observed only in the vancomycin.The control group and the treatment group show no significantly differences on all drug concentration.Neither of the bioactivities of the joint fluids.Conclusions Cefuroxime and gentamycin,which were respectively adminnistered as system and local prophylactic antibiotic in TKA,were sufficient to inhibit MSSA during its administration.Vancomycin-loaded cement had antibacterial activity against MRSA.The 40 g bone cement loaded with 0.5g vancomycin and that loaded with 1g vancomycin had the same bioactivities.The cement loaded with 0.5g vancomycin / 40 g PMMA is worth popularizing in clinical.