Treatment And Basic Research Of Prosthetic Joint Infection After Total Knee Arthroplasty

Background and purpose:This article includes two parts:clinical research and experimental research.The clinical research is treatment and effect analysis of prosthetic joint infection after total knee arthroplasty.Prosthetic joint infection?PJI?is a serious complication after total knee arthroplasty?TKA?.If the infection control is not ideal,it may lead to serious consequences such as amputation and even life threatening.It is of great significance to perform timely and effective treatment for PJI.Selecting different treatment methods will affect the success rate and prognosis of treatment.We reviewed and analyzed the patients with PJI after TKA from January 2012 to October 2017 in the bone and joint department of the first Bethune hospital of Jilin University,and followed up to study the infection type,infection treatment strategy and prognosis.The experimental research is 3D printed porous titanium rods equipped with vancomycin-loaded hydrogels and Polycaprolactone?PCL?membranes for intelligent antibacterial drug release.Implant-related infections are catastrophic complications of orthopaedic surgery.It is of great significance to perform antibacterial coating on the surface of orthopedic implants to prevent implant-related infections.Among them,coating could intelligently release antibiotics for active killing bacteria in the presence of bacterial infections is the most clinically useful.The purpose of this experiment is to explore the effect of PEG-b-PCL as a drug carrier and the feasibility of applying PCL to intelligent antibacterial coating of orthopaedic implants.Methods:The clinical research part include retrospective analysis of 24 cases of PJI after TKA from January 2012 to October 2017 in bone and joint department of the first Bethune hospital of Jilin University.The patient's age,gender,etiology for the initial TKA surgery,duration of infection,bacteriological data,treatment modalities,revision interval,antibiotic use,and treatment effect were collected.The infection was classified according to the Tsukayama classification;The follow-up of the curative effect included:the patient's knee HSS score,knee range of motion,inflammation indicators,and the knee X-ray.In the experimental research,porous titanium rods were fabricated using3D printing technology.Vancomycin was implanted in the pores of the implant,and mPEG₇₅₀-b-PCL₂₅₀₀ gel was used as a drug carrier to improve the drug burst phenomenon.The titanium rods'pores adsorbed the gel.The PCL membrane was coated on the surface and the lipase solution was used to simulate bacterial infection,the antibacterial effect of the system was verified by the paper antibacterial experiment.Results:Retrospective analysis of 24 cases of PJI after TKA,the average time of infection was 8.3 months after primary TKA surgery?1 week-48 months?.There were 0 patients with type I infection,4 patients with type II infection,1patient with type III infection,and 19 patients with type IV infection.A total of 13patients were found to have pathogenic bacteria.The detection rate of pathogenic bacteria was 54.2%,mainly gram-positive bacterial infection.8patients underwent debridement and implant retention surgery,6 were successful,1 patient failed and undergo a second-stage revision,1 patient was lost;14 patients underwent two-stage revision?including one patient who had failed debridement and implant retention surgery?.Among them,9 patients completed the second-stage revision,and no recurrence of infection occurred at the final follow-up.2 patients had recurrence of infection after primary resection.3 patients were lost;2 patients have prosthesis loosing and were proposed revision surgery,because of personal reasons they chose knee arthroplasty.1 patient with severe infection chose amputation.Experimental results show that PEG-b-PCL gel can improve drug burst phenomenon and PCL membrane can be rapidly degraded in lipase solution.Conclusions:Tsukayama classification is important for guiding the treatment of PJI after TKA.In addition to Tsukayama classification,different factors should be considered when choose the treatment plan such as the degree of infection,whether the prosthesis is loose,and the patient's wishes.The second-stage revision surgery is effective in the treatment of PJI after TKA;The debridement and implant retention surgery has a good therapeutic effect on early infection and has a certain curative effect on chronic infection.For chronic infection,under the premise of thoroughly debridement,it is also optional for debridement and implant retention surgery.Drug release and antibacterial experiments in vitro demonstrated that the temperature-sensitive PEG-b-PCL gel can improve the phenomenon of drug burst and does not destroy the vancomycin,so it could be used as drug carrier.The PCL membrane can be rapidly degraded when the lipase concentration is as low as 0.2 mg/ml,so that the encapsulated vancomycin can be stably released to achieve the purpose of inhibiting bacterial.