| Background:Bone cement spacers are widely used in two-stage revision surgeries for periprosthetic joint infection（PJI）.Current spacer design results in insufficient release of drugs,therefore,current spacers have low efficacy.In this study,we evaluated the antibiotic elution performance,ultimate compressive strength,biocompatibility and antibacterial effect of clinically common vancomycin-loaded bone cement.we explored a set of alternative articular spacer using 3D printing technology.This novel spacer will increase effectiveness of revision surgery for PJI.Methods:In vitro experiment,two kinds of vancomycin in different doses were mixed into the two kinds of bone cement to make a standard bone cement discs or cylinders;Vancomycin release was measured by fluorescence polarization immunoassay.Ultimate compressive strength is measured by axial compression;The L929 mouse fibroblasts were co-cultured with material eluent.The cytotoxicity was evaluated by cell proliferation kit CCK-8 and cell morphology staining,and the antibacterial effect in vitro was evaluated by blood Agar plate,bacteriostatic experiment,live bacterial fluorescence staining.In the clinical trial,the spacer was designed using CAD software and constructed on site using 3D-printed silicone mold during debridement surgery.We carried out a retrospective study among patients undergoing treatment using traditional static and new articular spacers.Infection control rate,bone loss,difficulty of revision surgery,knee joint range of motion,function evaluation,and subjective satisfaction of the patients in the two groups were compared.Results:In vitro study results showed that Palacos R bone cement was superior to Osteobond bone cement in terms of antibiotic elution performance,and sterile vancomycin（Hospira Inc.,USA）was superior to Vanco（Gentle Pharmaceutical Co.,Taiwan）,with statistical significance（P < 0.05）.The mechanical strength of bone cement in the low dose antibiotic group was not significantly different from that in the control group,while the ultimate compressive strength in the high dose antibiotic group was significantly lower than that in the control group,and the difference was statistically significant（P < 0.05）.There was no significant difference in cytotoxicity of vancomycin bone cement with common dose.Compared with the control group,vancomycin-loaded bone cement had obvious bactericidal ability,and there was significant difference in antibacterial effect between low-dose and high-dose antibiotics（P < 0.05）;The clinical study included 42 patients who underwent secondary revision knee surgery between January 2014 and November 2019.Twenty-two patients were treated with static antibiotic cement spacers,with a mean age of 67.2 years and a mean follow-up of 43 months.The other 20 patients were treated with a 3D printing-assisted antibiotic loaded articulating spacers,with a mean age of 65.5 years and a mean follow-up of 18 months.Patients in the articular group showed significantly lower bone loss on the femur site and tibial site compared with patients in the static group,and the difference is statistically significant（P <0.05）.In addition,patients in the articular group showed significantly less operation time,intraoperative blood loss,and improved knee function and patient overall satisfaction compared with patients in the static group.Conclusion:The commonly used dose of vancomycin bone cement has good biocompatibility and antibacterial ability.Different doses and different brands of vancomycin and bone cement have great influence on the elution effect and mechanical strength of antibiotic bone cement.The 3D printing-assisted articular spacer provides satisfactory range of motion during the interim period,prevents bone loss,facilitates second-stage reimplantation and postoperative rehabilitation,and results in low reinfection and complication rates. |
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