Candidal periprosthetic joint infection after primary total knee arthroplasty combined with ipsilateral intertrochanteric fracture: A case report

BACKGROUND Candidal periprosthetic joint infection is a rare and difficult to diagnose complication of total knee arthroplasty.The treatment of such complications is inconclusive and may include prosthesis removal,debridement,arthrodesis,and extensive antifungal therapy to control the infection.CASE SUMMARY A 62-year-old male with a history of total knee arthroplasty(TKA)in his left knee presented with ipsilateral knee pain and a sinus discharge 20 mo after TKA.The patient was previously evaluated for left knee pain,swelling,and a transient fever one month postoperatively.Prothesis removal and insertion of a cement spacer were performed in a local hospital six months prior to the current presentation.Medical therapy included rifampicin and amphotericin which were administered for 4 wk following prosthesis removal.A second debridement was performed in our hospital and Candida parapsilosis was detected in the knee joint.Fourteen weeks following the latter debridement,the patient suffered a left intertrochanteric fracture and received closed reduction and internal fixation with proximal femoral nail anterotation.Two weeks after fracture surgery,a knee arthrodesis with autograft was performed using a double-plate fixation.The patient recovered adequately and was subsequently discharged.At the two-year follow-up,the patient has a stable gait with a pain-free,fused knee.CONCLUSION Fungal periprosthetic joint infection following TKA may be successfully and safely treated with prosthesis removal,exhaustive debridement,and arthrodesis after effective antifungal therapy.Ipsilateral intertrochanteric fractures of the affected knee can be safely fixated with internal fixation if the existing infection is clinically excluded and aided by the investigation of serum inflammatory markers.

Good accuracy of the alpha-defensin lateral flow test for hip periprosthetic joint infection: A pilot study in a retrospective cohort of 52 patients

BACKGROUND The alpha-defensin lateral flow(ADLF)test is a new diagnostic tool for periprosthetic joint infection(PJI).Test accuracy for combined cohorts of hip and knee PJI has been reported to be good.AIM To assess the accuracy of the ADLF test for hip PJI,and to compare three different diagnostic criteria for PJI.METHODS A cohort of 52 patients was identified,with a painful or poor-functioning total hip-or hemi-arthroplasty,that underwent aspiration and a subsequent ADLF test.PJI was diagnosed with Musculoskeletal Infection Society(MSIS)criteria,and sensitivity,specificity,overall accuracy,positive predictive value and negative predictive value were calculated.Furthermore,test specifics were compared with the European Bone and Joint Infection Society(EBJIS)and 2018 International Consensus Meeting(ICM)criteria for PJI.RESULTS Using MSIS criteria,sensitivity was 100%(CI:54%-100%)and specificity was 89%(CI:76%-96%).Six true positives and 5 false positives were found,including one case of metallosis.Using EBJIS criteria,more PJIs were found(11 vs 6),sensitivity was lower(71%,CI:42%-92%)and specificity was higher(97%,CI:86%-100%),with 4 false negatives and one false positive result.Using 2018 ICM criteria,sensitivity was 91%(62%-100%)and specificity 100%(91%-100%).The results in this cohort are comparable to previous studies.CONCLUSION Overall test accuracy of the ADLF test was good in this cohort,with a sensitivity of 100%and specificity of 89%.Using different PJI definition criteria,sensitivity and specificity changed slightly but overall accuracy remained around 90%.Using the ADLF test in metallosis cases can result in false positive results and should be performed with caution.

Analysis of the clinical efficacy of two-stage revision surgery in the treatment of periprosthetic joint infection in the knee:A retrospective study

BACKGROUND Periprosthetic joint infection(PJI)is a catastrophic complication that can occur following total knee arthroplasty(TKA).Currently,the treatment for PJI mainly includes the use of antibiotics alone,prosthetic debridement lavage,primary revision,secondary revision,joint fusion,amputation,etc.AIM To explore the clinical effect of two-stage revision surgery for the treatment of PJI after TKA.METHODS The clinical data of 27 patients(3 males and 24 females;age range,47–80 years;mean age,66.7±8.0 years;27 knees)with PJI treated with two-stage revision surgery in our hospital between January 1,2010 and December 31,2020 were analyzed retrospectively.The following outcomes were compared for changes between preoperative and last follow-up results:Erythrocyte sedimentation rate(ESR),C-reactive protein(CRP),visual analogue scale(VAS)scores,Hospital for Special Surgery(HSS)scores,knee range of motion(ROM),and infection cure rates.RESULTS All 27 patients were followed up(range,13–112 mo).The ESR(14.5±6.3 mm/h)and CRP(0.6±0.4 mg/dL)of the patients at the last follow-up were significantly lower than those at admission;the difference was statistically significant(P<0.001).The postoperative VAS score(1.1±0.7),HSS score(82.3±7.1),and knee ROM(108.0°±19.7°)were significantly improved compared with those before the surgery;the difference was statistically significant(P<0.001).Of the 27 patients,26 were cured of the infection,whereas 1 case had an infection recurrence;the infection control rate was 96.3%.CONCLUSION Two-stage revision surgery can effectively relieve pain,control infection,and retain good joint function in the treatment of PJI after TKA.

Preoperative and postoperative risk factors for periprosthetic joint infection in primary total hip arthroplasty:A 1-year experience

BACKGROUND Periprosthetic joint infection(PJI)in primary total hip replacement(THR)is one of the most important threats in orthopedic surgery,so one important surgeon’s target is to avoid or early diagnose a PJI.Although the incidence of PJI is very low(0.69%)in our department,with an average follow-up of 595 d,this infection poses a serious threat due to the difficulties of treatment and the lower functional outcomes after healing.AIM To study the incidence of PJI in all operations occurring in the year 2016 in our department to look for predictive signs of potential infection.METHODS We counted 583 THR for 578 patients and observed only 4 cases of infection(0.69%)with a mean follow-up of 596 d(min 30,max 1451).We reviewed all medical records to collect the data:duration and time of the surgery,presence,type and duration of the antibiotic therapy,preoperative diagnosis,blood values before and after surgery,transfusions,presence of preoperative drugs(in particularly anticoagulants and antiaggregant,corticosteroids and immunosuppressants),presence of some comorbidities(high body mass index,blood hypertension,chronic obstructive pulmonary disease,cardiac ischemia,diabetes,rheumatological conditions,previous local infections).RESULTS No preoperative,intraoperative,or postoperative analysis showed a higher incidence of PJI.We did not find any class with evident major odds of PJI.In our study,we did not find any border value to predict PJI and all patients had similar values in both groups(non-PJI and PJI).Only some categories,such as female patients,showed more frequency of PJI,but this difference related to sex was not statistically significant.CONCLUSION We did not find any category with a higher risk of PJI in THR,probably due to the lack of few cases of infection.

Two-stage revision in periprosthetic knee joint infections

Periprosthetic joint infection(PJI)following total knee arthroplasty is one of the most catastrophic and costly complications that carries significant patient wellness as well as economic burdens.The road to efficiently diagnosing and treating PJI is challenging,as there is still no gold standard method to reach the diagnosis as early as desired.There are also international controversies with respect to the best approach to manage PJI cases.In this review,we highlight recent advances in managing PJI following knee arthroplasty surgery and discuss in depth the two-stage revision method.

Synovial Fluid C-reactive Protein as a Diagnostic Marker for Periprosthetic Joint Infection： A Systematic Review and Meta-analysis

Background： Periprosthetic joint infection （PJI） is the main cause of failure following total joint arthroplasty. Until now, the diagnosis of PJI is still confronted with technical limitations, and the question of whether synovial fluid biomarker, C-reactive protein （CRP）, can provide high value in the diagnosis of PJl remains unanswered and, therefore, was the aim of the study. Methods： First, we conducted a systematic review on CRP in the diagnosis of PJI by searching online databases using keywords such as ＂periprosthetic joint infection＂, ＂synovial fluid＂, and ＂C-reactive protein＂. Eligible studies providing sufficient data to construct 2 × 2 contingency tables were then selected based on the list of criteria and the quality of included studies was assessed subsequently. Finally, the reported sensitivity, specificity, diagnostic odds ratio （DOR）, summary receiver operating characteristic （SROC） curve, and the area under the SROC （AUSROC） were pooled together and used to evaluate overall diagnostic performance. Results： Seven studies were included in our review, six of which comprising a total of 456 participants were further investigated in our meta-analysis. The pooled sensitivity, specificity, and DOR were 0.92 （95% confidence interval [CI]： 0.86-0.96）, 0.90 （95% CI： 0.87-0.93）, and 101.40 （95% CI： 48.07-213.93）, respectively. The AUSROC was 0.9663 （standard error, 0.0113）. Conclusions： Synovial fluid CRP is a good biomarker for the diagnosis of PJI with high sensitivity and specificity.

Treatment of periprosthetic knee infection and coexistent periprosthetic fracture:A case report and literature review

BACKGROUND Periprosthetic joint infection(PJI) and periprosthetic fracture(PPF) are among the most serious complications following total knee arthroplasty. Herein, we present one patient with these two complications with details on the characteristics, treatment strategy, and outcome.CASE SUMMARY A 69-year-old female patient who suffered from PJI and PPF following total knee arthroplasty was treated by a two-stage revision surgery. After thorough foreign material removal and debridement, we used a plate that was covered with antibiotic-loaded bone cement to link with a hand-made cement spacer to occupy the joint space and fix the fracture. Although the infection was cured, the fracture did not heal and caused bone defect due to the long interval between debridement and revision. In the revision surgery, a cemented stem and cortical allogenic splints were used to reconstruct the fracture and bone defect. At the final followup 27 mo after revision, the patient was satisfied with postoperative knee functions with satisfactory range of motion(104°) and Hospital for Special Surgery knee score(82 points). The radiographs showed no loosening of the prosthesis and that the bone grafts healed well with the femur.CONCLUSION Our two-stage revision surgery has proved to be successful and may be considered in other patients with PJI and PPF.

Comprehensive meta-analysis of antibiotic-impregnated bone cement versus plain bone cement in primary total knee arthroplasty for preventing periprosthetic joint infection

Purpose:Antibiotic-loaded bone cement(ALBC)was usually used to prevent periprosthetic joint infection(PJI)in primary total knee arthroplasty(PTKA),but whether to use ALBC or plain bone cement in PTKA remains unclear.We aimed to compare the occurrence rate of PJI using two different cements,and to investigate the efficacy of different antibiotic types and doses administered in preventing surgical site infection(SSI)with ALBC.Methods:The availability of ALBC for preventing PJI was evaluated by using a systematic review and meta-analysis referring to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.Existing articles until December 2021 involving PTKA patients with both ALBC and plain bone cement cohorts were scanned by searching"total knee arthroplasty","antibiotic-loaded cement","antibiotic prophylaxis","antibiotic-impregnated cement"and"antibiotic-laden cement"in the database of PubMed/MEDLINE,Embase,Web of Science and the Cochrane Library.Subgroup analysis included the effectiveness of different antibiotic types and doses in preventing SSI with ALBC.The modified Jadad scale was employed to score the qualities of included articles.Results:Eleven quantitative studies were enrolled,including 34,159 knees undergoing PTKA.The meta-analysis results demonstrated that the use of prophylactic ALBC could significantly reduce the prevalence of deep incisional SSI after PTKA,whereas there was no significant reduction in the rate of superficial incisional SSI.Moreover,gentamicin-loaded cement was effective in preventing deep incisional SSI,and the use of high-dose ALBC significantly reduced the rate of deep incisional SSI after PTKA.Besides,no significant adverse reactions and complications were stated during the use of ALBC in PTKA.Conclusion:The preventive application of ALBC during PTKA could reduce the rates of deep PJI.Furthermore,bone cement containing gentamicin and high-dose ALBC could even better prevent deep infection after PTKA.However,the existing related articles are mostly single-center and retrospective studies,and further high-quality ones are needed for confirmation.

Knowledge and attitudes of orthopedic surgeons regarding prosthesis joint infection

BACKGROUND Periprosthetic joint infection(PJI)is a critical complication after joint arthroplasty and is accompanied by increasing rates of morbidity and mortality.Several studies have aimed at preventing PJI.AIM To research the knowledge level and attitudes of orthopedic surgeons,who play a key role in both preventing and managing PJI.METHODS We conducted a web-based survey to evaluate orthopedic surgeons'knowledge level and attitudes regarding PJI.The Likert scale survey utilized consisted of 30 questions which were prepared based on the"Proceedings of the International Consensus on Periprosthetic Joint Infection".RESULTS A total of 264 surgeons participated in the survey.Their average age was 44.8,and 173 participants(65.5%)had more than 10 years of experience.No statistically significant relationship was found between the PJI knowledge of the surgeons and their years of experience.However,participants who worked in training and research hospitals demonstrated higher levels of knowledge than the ones in the state hospitals.It was also noticed that surgeons'knowledge concerning the duration of antibiotic therapy and urinary infections was not consistent with their attitudes.CONCLUSION Even though orthopedic surgeons have adequate knowledge about preventing and managing PJI,their attitudes might contradict their knowledge.Future studies are required to examine the causes and solutions of the contradictions between orthopedic surgeons'knowledge and attitudes.

Fungal periprosthetic joint infection:Rare but challenging problem

Periprosthetic joint infection (PJI) is the most difficult complication following total joint arthroplasty. Most of the etiological strains, accounting for over 98% of PJI, are bacterial species, with Staphylococcus aureus and Coagulase-negative staphylococci present in between 50% and 60% of all PJIs. Fungi, though rare, can also cause PJI in 1%—2% of cases and can be challenging to manage. The management of this uncommon but complex condition is challenging due to the absence of a consistent algorithm. Diagnosis of fungal PJI is difficult as isolation of the organisms by traditional culture may take a long time, and some of the culture-negative PJI can be caused by fungal organisms. In recent years, the introduction of next-generation sequencing has provided opportunity for isolation of the infective organisms in culture-negative PJI cases. The suggested treatment is based on consensus and includes operative and non-operative measures. Two-stage revision surgery is the most reliable surgical option for chronic PJI caused by fungi. Pharmacological therapy with antifungal agents is required for a long period of time with antibiotics and included to cover superinfections with bacterial species. The aim of this review article is to report the most up-to-date information on the diagnosis and treatment of fungal PJI with the intention of providing clear guidance to clinicians, researchers and surgeons.

Combination of C-reactive protein and fibrinogen is useful for diagnosing periprosthetic joint infection in patients with inflammatory diseases

Background:The screening of periprosthetic joint infection(PJI)in patients with inflammatory diseases before revision arthroplasty remains uncertain.Serum C-reactive protein(CRP),erythrocyte sedimentation rate(ESR),plasma fbrinogen(FIB),monocyte/lymphocyte ratio,and neutrophil/lymphocyte ratio(NLR)can help screening PJI,but their values in patients with infammatory diseases have not been determined.Methods:Patients with inflammatory diseases who underwent revision hip or knee arthroplasty at West China Hospital,Sichuan University,from January 2008 to September 2020 were divided into infected and non-infected groups based on the 2013 International Consensus Meeting criteria.Sensitivity and specificity of the tested biomarkers for diagnosing infection were determined based on receiver operating characteristic(ROC)curves,and optimal cutoffs were determined based on the Y ouden index.The diagnostic ability of these biomarkers was re-assessed after combining them with each other.Results:A total of 62 patients with inflammatory diseases were studied;of them 30 were infected.The area under the ROC curve was 0.813 for CRP,0.638 for ESR,0.795 for FIB,and 0.656 for NLR.The optimal predictive cutoff of CRP was 14.04 mg/L with a sensitivity of 86.2%and a specificity of 68.7%,while FIB had a sensitivity of 72.4%and a specificity of 81.2%with the optimal predictive cutoff of 4.04 g/L.The combinations of CRP with FIB produced a sensitivity of 86.2%and specificity of 78.1%.Conclusion:CRP with a slightly higher predictive cutoff and FIB are useful for screening PJI in patients with inflammatory diseases,and the combination of CRP and FIB may further improve the diagnostic values.

Performance of alpha-defensin lateral flow test after synovial fluid centrifugation for diagnosis of periprosthetic knee infection

BACKGROUND The quantitative alpha-defensin enzyme-linked immunosorbent assay(ELISA)demands a prior synovial fluid centrifugation,whereas this processing is not routinely required prior to the alpha-defensin lateral flow test.AIM To evaluate whether a prior synovial fluid centrifugation could lead the lateral flow performance to achieve comparable results to ELISA during periprosthetic joint infection(PJI)diagnosis.METHODS Fifty-three cases were included in this study:22 classified as PJI and 31 classified as aseptic cases,according to Musculoskeletal Infection Society 2013 criteria.Synovial fluid samples were submitted to centrifugation,and the supernatant was evaluated by ELISA and lateral flow tests.The sensitivity(SE),specificity(SP)and accuracy of each method were calculated as well as the agreement between those two methods.RESULTS In all of the 31 samples from aseptic patients,alpha-defensin ELISA and lateral flow tests showed negative results for infection.Regarding the 22 infected patients,the lateral flow test was positive in 19 cases(86.4%)and the ELISA was positive in 21(95.5%).Sensibility,SP and accuracy were,respectively,86.4%(95%CI:65.1%-97.1%),100%(95%CI:88.8%-100%)and 93.2%(95%CI:82.8%-98.3%)for the lateral flow test and 95.5%(95%CI:77.2%-99.9%),100%(95%CI:88.8%-100%)and 98.1%(95%CI:89.9%-100%)for ELISA.An agreement of 96.2%between those methods were observed.No statistical difference was found between them(P=0.48).CONCLUSION Alpha-defensin lateral flow test showed high SE,SP and accuracy after a prior synovial fluid centrifugation,achieving comparable results to ELISA.Considering the lower complexity of the lateral flow and its equivalent performance obtained in this condition,a prior centrifugation might be added as a valuable step to enhance the PJI diagnosis.

Utility of D-dimer in total joint arthroplasty

As the number of patients receiving total joint replacements continues to rise,considerable attention has been directed towards the early detection and prevention of postoperative complications.While D-dimer has long been studied as a diagnostic tool in venous thromboembolism(VTE),this assay has recently received considerable attention in the diagnosis of periprosthetic joint infection(PJI).D-dimer values are substantially elevated in the acute postoperative period after total joint arthroplasty,with levels often exceeding the standard institutional cutoff for VTE(500µg/L).The utility of D-dimer in detecting VTE after total joint replacement is currently limited,and more research to assess its value in the setting of contemporary prophylaxis protocols is warranted.Recent literature supports D-dimer as a good to excellent biomarker for the diagnosis of chronic PJI,especially when using serum sample technique.Providers should exercise caution when interpreting D-dimer levels in patients with inflammatory and hypercoagulability disorders,as the diagnostic value is decreased.The updated 2018 Musculoskeletal Infection Society criteria,which includes D-dimer levels>860µg/L as a minor criterion,may be the most accurate for diagnosing chronic PJI to date.Larger prospective trials with transparent lab testing protocols are needed to establish best assay practices and optimal cutoff values for D-dimer in the diagnosis of PJI.This review summarizes the most current literature on the value of D-dimer in total joint arthroplasty and elucidates areas for future progress.

Use of topical vancomycin powder in total joint arthroplasty:Why the current literature is inconsistent?

Periprosthetic joint infection(PJI)is a rare but terrible complication in hip and knee arthroplasty,and the use of topical vancomycin powder(VP)has been investigated as a tool to potentially reduce its incidence.However,there remains no consensus on its efficacy.Therefore,the aim of this review is to provide an overview on the application of topical vancomycin in orthopaedic surgery focusing on the recent evidence and results in total joint arthroplasty.Several systematic reviews and meta-analyses on topical VP in hip and knee arthroplasty have been recently published reporting sometimes conflicting results.Apart from all being limited by the quality of the included studies(mostly level III and IV),confounding variables are often included potentially leading to biased conclusions.If taken into consideration the exclusive use of VP in isolation,the available data,although very limited,suggest that it does not reduce the infection rate in routine primary hip and knee arthroplasty.Therefore,we still cannot advise for a routinary application.A properly powered randomized-controlled trial would be necessary to clarify the role of VP in hip and knee arthroplasty.Based on the analysis of the current evidence,the use of topical VP appears to be safe when used locally in terms of systemic adverse reactions,hence,if proven to be effective,it could bring great benefits due to its low cost and accessibility.

Role of joint aspiration before re-implantation in patients with a cement spacer in place

BACKGROUND The usefulness of a mandatory joint aspiration before re-implantation in patients with a cement spacer already in place is unclear.AIM To evaluate the role of culturing synovial fluid obtained by joint aspiration before re-implantation in patients who underwent a two-stage septic revision.METHODS A retrospective observational study was conducted,including patients that underwent a two-stage septic revision(hip or knee)from 2010 to 2017.After the first stage revision and according to intraoperative culture results,all patients were treated with an antibiotic protocol for 6-8 wk.Following 2 wk without antibiotics,a culture of synovial fluid was obtained.The results of these cultures were recorded and compared with cultures obtained during re-implantation surgery.RESULTS Forty-one patients(20 hip and 21 knee spacers)were included in the final analysis.In 39 cases,the culture of synovial fluid was negative,while in the remaining 2 cases(knee spacers)no analysis was possible due to dry tap.In 5 of the patients,two or more intraoperative cultures taken during the re-implantation surgery were positive.CONCLUSION We found no evidence to support mandatory joint aspiration before re-implantation in patients with a cement spacer in place.

Physiologic postoperative presepsin kinetics following primary cementless total hip arthroplasty:A prospective observational study

BACKGROUND Presepsin is an emerging biomarker in the diagnosis of sepsis.In the field of orthopaedics,it could be useful in diagnosing and managing periprosthetic joint infections.AIM To define the normal postoperative presepsin plasmatic curve,in patients undergoing primary cementless total hip arthroplasty(THA).METHODS Patients undergoing primary cementless THA at our Institute were recruited.Inclusion criteria were:Primary osteoarthritis of the hip;urinary catheter time of permanence<24 h;peripheral venous cannulation time of permanence<24 h;no postoperative homologous blood transfusion administration and hospital stay≤8 d.Exclusion criteria were:The presence of other articular prosthetic replacement or bone fixation devices;chronic inflammatory diseases;chronic kidney diseases;history of recurrent infections or malignant neoplasms;previous surgery in the preceding 12 mo;diabetes mellitus;immunosuppressive drug or corticosteroid assumption.All the patients received the same antibiotic prophylaxis.All the THA were performed by the same surgical and anaesthesia team;total operative time was defined as the time taken from skin incision to completion of skin closure.At enrollment,anthropometric data,smocking status,osteoarthritis stage according to Kellgren and Lawrence,Harris Hip Score,drugs assumption and comorbidities were recorded.All the patients underwent serial blood tests,including complete blood count,presepsin(PS)and C-reactive protein 24 h before arthroplasty and at 24,48,72 and 96 h postoperatively and at 3,6 and 12-mo follow-up.RESULTS A total of 96 patients(51 female;45 male;mean age=65.74±5.58)were recruited.The mean PS values were:137.54 pg/mL at baseline,192.08 pg/mL at 24 h post-op;254.85 pg/mL at 48 h post-op;259 pg/mL at 72 h post-op;248.6 pg/mL at 96-h post-op;140.52 pg/mL at 3-mo follow-up;135.55 pg/mL at 6-mo follow-up and 130.11 pg/mL at 12-mo follow-up.In two patients(2.08%)a soft-tissue infection was observed;in these patients,higher levels(>350 pg/mL)were recorded at 3-mo follow-up.CONCLUSION The dosage of plasmatic PS concentration is highly recommended in patients undergoing THA before surgery to exclude the presence of an unknown infection.The PS plasmatic concentration should be also assessed at 72 h postoperatively,evaluate the maximum postoperative PS value,and at 96 h post-operatively when a decrease of presepsin should be found.The lack of a presepsin decrease at 96 h post-operatively could be a predictive factor of infection.

Improved patient reported outcomes with functional articulating spacers in two-stage revision of the infected hip

BACKGROUND Two-stage revision arthroplasty with an antibiotic-loaded spacer is the treatment of choice in chronically infected total hip arthroplasties.Interval spacers can be functional articulating or prefabricated.Functional results of these spacers have scarcely been reported.AIM To compare retrospectively the patient reported outcome and infection eradication rate after two-stage revision arthroplasty of the hip with the use of a functional articulating or prefabricated spacer.METHODS All patients with two-stage revision of a hip prosthesis at our hospital between 2003 and 2016 were included in this retrospective cohort study.Patients were divided into two groups;patients treated with a functional articulating spacer or with a prefabricated spacer.Patients completed the Hip Osteoarthritis Outcome Score and the EQ-5D-3L(EQ-5D)and the EQ-5D quality of life thermometer(EQVAS)scores.Primary outcomes were patient reported outcome and infection eradication after two-stage revision.The results of both groups were compared to the patient acceptable symptom state for primary arthroplasty of the hip.Secondary outcomes were complications during spacer treatment and at final follow-up.Descriptive statistics,mean and range are used to represent the demographics of the patients.For numerical variables,students’t-tests were used to assess the level of significance for differences between the groups,with 95%confidence intervals;for binary outcome,we used Fisher’s exact test.RESULTS We consecutively treated 55 patients with a prefabricated spacer and 15 patients with a functional articulating spacer of the hip.The infection eradication rates for functional articulating and prefabricated spacers were 93%and 78%,respectively(P>0.05).With respect to the functional outcome,the Hip Osteoarthritis Outcome Score(HOOS)and its subscores(all P<0.01),the EQ-5D(P<0.01)and the EQVAS scores(P<0.05)were all significantly better for patients successfully treated with a functional articulating spacer.More patients in the functional articulating spacer group reached the patient acceptable symptom state for the HOOS pain,HOOS quality of life and EQ-VAS.The number of patients with a spacer dislocation was not significantly different for the functional articulating or prefabricated spacer group(P>0.05).However,the number of dislocations per patient experiencing a dislocation was significantly higher for patients with a prefabricated spacer(P<0.01).CONCLUSION Functional articulating spacers lead to improved patient reported functional outcome and less perioperative complications after two-stage revision arthroplasty of an infected total hip prosthesis,while maintaining a similar infection eradication rate compared to prefabricated spacers.

Antibiotic-free antimicrobial poly (methyl methacrylate) bone cements:A state-of-the-art review

Prosthetic joint infection(PJI)is the most serious complication following total joint arthroplasty,this being because it is associated with,among other things,high morbidity and low quality of life,is difficult to prevent,and is very challenging to treat/manage.The many shortcomings of antibiotic-loaded poly(methyl methacrylate)(PMMA)bone cement(ALBC)as an agent for preventing and treating/managing PJI are well-known.One is that microorganisms responsible for most PJI cases,such as methicillin-resistant S.aureus,have developed or are developing resistance to gentamicin sulfate,which is the antibiotic in the vast majority of approved ALBC brands.This has led to many research efforts to develop cements that do not contain gentamicin(or,for that matter,any antibiotic)but demonstrate excellent antimicrobial efficacy.There is a sizeable body of literature on these socalled“antibiotic-free antimicrobial”PMMA bone cements(AFAMBCs).The present work is a comprehensive and critical review of this body.In addition to summaries of key trends in results of characterization studies of AFAMBCs,the attractive features and shortcomings of the literature are highlighted.Shortcomings provide motivation for future work,with some ideas being formulation of a new generation of AFAMBCs by,example,adding a nanostructured material and/or an extract from a natural product to the powder and/or liquid of the basis cement,respectively.

Quantitative alpha-defensin testing: Is synovial fluid dilution important?

BACKGROUND Alpha-defensin has been widely studied for the diagnosis of periprosthetic joint infection(PJI).However,there is a lack of detailed information regarding the proper laboratory technique of the enzyme-linked immunosorbent assay(ELISA)method,such as sample dilution.AIM To assess the influence of dilution in the synovial fluid during ELISA for the diagnosis of knee PJI;and determine which dilution presents a better performance.METHODS Forty samples of synovial fluid from arthroplasty knees were included,17 in the infected group and 23 in the aseptic group,according to Musculoskeletal Infection Society criteria.Initially,five synovial fluid samples from each group were assessed for quantitative analysis of alpha-defensin using ELISA.Different dilution ratios(1:10,1:100,1:500,1:1000 and 1:5000)were tested based on the predetermined cutoff value of 5.2 mg/L.The dilutions that performed better were used to compare the results of all samples.RESULTS For infected cases,a gradual increase in the dilution of synovial fluid samples led to an equivalent increase in alpha-defensin level.The same was not observed in the aseptic cases.Both 1:1000 and 1:5000 dilutions presented satisfactory results to differentiate infected and aseptic cases.Further analyses were performed using 1:1000 and 1:5000 for all 40 samples.The 1:1000 dilution resulted in a sensitivity of 88.2%(95%CI,66%-98%)and specificity of 95.7%(95%CI,79%-99%),whereas the 1:5000 dilution presented a sensitivity of 94.1%(95%CI,73%-99%)and a specificity of 100%(95%CI,86%-100%).CONCLUSION The synovial fluid dilution had an important influence on the alpha-defensin ELISA results.Dilutions of 1:5000 showed the best performance for the diagnosis of knee PJI.The results of this study set the basis for a more reliable and reproducible alpha-defensin ELISA during the investigation of PJI,contributing to the expansion of this technique in different treatment centers worldwide.