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

Background and purpose:Periprosthetic joint infection（PJI）is a serious complication of orthopedic implants and is often referred to as a"catastrophic complication."If the infection cannot be controlled in time,it will not only increase the mental and economic burden of the patient,may even lead to serious consequences and threatening the patient’s life.Therefore,timely and effective treatment of infection is of great significance.Different treatment methods can be selected according to the patient’s economic condition,physical quality and different degrees of disease,and the success rate and prognosis of the treatment are also different.In order to clarify the differences in various treatment methods,we retrospectively analyzed the patients diagnosed as"infection after total hip arthroplasty"from January 2010 to January 2018 in the Department of Joint Surgery,Bethune First Hospital,Jilin University.Follow up to understand infection classification,treatment strategy,and prognosis.On the other hand,how to effectively prevent postoperative infection of orthopedic implants or effectively remove bacteria in the early stage of infection is very important to reduce the incidence of PJI.There are many related studies at home and abroad,in which antibiotics can be preserved in non-bacterial infections.Related studies on the intelligent release of antibiotics to kill bacteria when bacteria are infected have clinical utility.In this experiment,we combined a 3D printed porous titanium scaffold with a polyethylene glycol-b-polycaprolactone（PEG-b-PCL）hydrogelvancomycinanda polycaprolactone（PCL）membrane.Through the previous drug release experiments,PCLmembranedissolutionexperimentsandinvitro bacteriostatic experiments,we confirmed that the drug release of the composite material remained stable and no burst release,the PCL membrane dissolved rapidly and the antibacterial activity in vitro was obvious.Based on the preliminary work,this reasearch further studied the biocompatibility of the composite and the control the infection effectively.Methods:The clinical research section reviewed 53 cases of the joint surgery of the Bethune First Hospital of Jilin University from January 2010 to January 2018,diagnosed as"infection after artificial total hip arthroplasty".The age,sex,whether the initial replacement surgery,the cause of the primary replacement surgery,the time of the infection from the replacement surgery,the time from the onset of infection,the type of bacteria,the treatment method,the interval between revisions,the use of antibiotics,and the therapeutic effect were collected.Efficacy follow-up included:patient hip Harris score,inflammation index,pelvic orthotopic X-ray film.The experimental research includes MTT method to detect the cytocompatibility of composite materials,muscle bag method to detect the biocompatibility of composite materials.The infection model was made and the anti-infective effect of the composite was evaluated.Results:A total of 53 patients with periprosthetic infection after total hip arthroplasty were retrospectively analyzed.All patients underwent bacterial culture and 42cases were positive for pathogenic bacteria.The detection rate of pathogenic bacteria was 79.2%.Among them,34 cases（80.95%）of Gram-positive bacteria and 8 cases（19.05%）of Gram-negative bacteria,the most common pathogens were Staphylococcus aureus（13 cases）and Staphylococcus epidermidis（9 cases）.Twenty-three patients with two-stage revision and 12patients with debridement retention prosthesis.Among the patients who underwent second-stage replacement therapy,there were 1 case of Conventry type I infection,10 cases of type II infection,12 cases of type III infection,4patients were lost.The average follow-up time was 41.72 months.Two patients with Conventry type I infection,4 cases of type II infection and 6 cases of type III infection were treated with debridement and prosthesis treatment,2patients lost follow-up,one patient died of liver cancer,an average follow-up time of 56.29 months,and the operation failed in 4 cases,with a success rate of 55.6%.In the experimental study,it was found that the results of MTT detection of cell co-culture with original titanium material and titanium+PCL film material have no significantly different except for the 14th day.The biocompatibility in vivo find that none of titanium,titanium+mPEG₇₅₀-b-PCL₂₅₀₀hydrogel and titanium+mPEG₇₅₀-b-PCL₂₅₀₀+PCL film showed obvious immunological rejection,and pathological examination of liver and kidney morphology without obvious abnormalities.The anti-infective properties of Ti+mPEG₇₅₀-b-PCL₂₅₀₀hydrogel and Ti+mPEG₇₅₀-b-PCL₂₅₀₀hydrogel with vancomycin+PCL firm were significantly better than those of Ti+vancomycin+PCL film.Compared with pure titanium,the Ti+vancomycin+PCL film had a mild inflammatory response in the early stage of the experiment,and the inflammatory reaction was similar at the end of the experiment.Conclusions:PJI treatment depends on local soft tissue conditions,bone conditions,prosthesis stability,different stages of infection,bacterial type and general condition of the patient to choose different treatment options.Factors that affect the success rate of debridement retention prosthesis include:duration of infection symptoms,preoperative WBC,ESR,CRP levels,early use of sensitive antibiotics after bacterial culture and intraoperative exchange of mobile parts.Nonprimary THA infection of PJI patients is not recommended for debridement and retention prosthesis treatment.The two-stage replacement is stable and reliable,and the joint pain and function improvement before and after surgery are the preferred treatment for Conventry type III infection and severe PJI.The 3D printed titanium material equipped with the mPEG₇₅₀-b-PCL₂₅₀₀hydrogel coated PCL film has good biocompatibility in vitro and in vivo,and the PCL film can gradually degrade and release antibiotics when infection occurs around the implant.mPEG₇₅₀-b-PCL₂₅₀₀hydrogel exhibits sustained and stable antibiotic release both in vitro and in vivo,which can effectively prevent the release of antibiotics.