关节液α防御素-1检测在人工关节感染诊断中的应用价值

目的探讨关节液α防御素-1(AD-1)检测在人工关节感染(PJI)诊断中的应用价值。方法选取2013年3月至2015年10月福建省内多家三甲医院骨科45例需行人工关节翻修术患者,男性18例,女性27例,平均年龄(60±14)岁。根据美国肌肉骨骼感染学会(MSIS)诊断标准,纳入标准为全髋及全膝关节置换术后需要进行翻修手术及术后怀疑感染的患者等,排除标准为存在其他身体部位感染病灶等,分为感染组22例,非感染组23例。对45例患者进行关节腔穿刺抽取关节液,采用酶联免疫吸附法(ELISA)检测关节液中AD-1的表达水平。通过受试者工作曲线特征(ROC)曲线计算AD-1、关节液白细胞计数(SF-WBC)、多核比(PMN%)、红细胞沉降率(ESR)、C反应蛋白(CRP)的敏感性及特异性,χ~2检验计算细菌培养的敏感性及特异性。AD-1与各指标间的敏感性及特异性采用χ~2进行比较分析。结果 AD-1诊断PJI的敏感性为86.4%,特异性为91.2%,曲线下面积为0.95。45例患者合并有系统性炎症疾病的患者占31.1%,感染组抽取关节液前有使用过抗生素治疗的患者59%,但AD-1的表达水平并未受到这两项因素的影响。细菌培养、SF-WBC、PMN%、ESR、CRP的敏感性从80%到90.9%,特异性从56.5%到76%。AD-1诊断PJI的敏感性比细菌培养、PMN%、ESR、CRP高,比SF-WBC低;而AD-1诊断PJI的特异性高于各诊断指标。AD-1诊断PJI的特异性与PMN%、ESR、CRP比较差异有统计学意义(P0.05),而与细菌培养、SF-WBC比较差异无统计学意义(P0.05);AD-1诊断PJI的敏感性与细菌培养、SF-WBC、PMN%、ESR、CRP比较差异无统计学意义(P0.05)。结论 AD-1诊断PJI具有较高的敏感性及特异性,可作为诊断PJI的一项潜在诊断指标。     

血清D-二聚体在关节假体周围感染诊断中的意义

[目的]探讨血清D-二聚体在关节假体周围感染(prosthetic joint infection, PJI)诊断中的意义。[方法]回顾性分析本科2016年6月～2018年6月收治的80例患者,其中初次置换组33例,PJI分期翻修24例,无菌松动翻修术组23例。比较三组患者术前血清C-反应蛋白(CRP)、血沉(ESR)、D-二聚体等数据。[结果]三组患者一般资料比较差异无统计学意义(P0.05)。PJI患者血清CRP、ESR水平显著高于初次关节置换及无菌性松动患者(P0.05),PJI患者血清D-二聚体水平显著高于初次置换者(P0.05),但与无菌性松动患者体内D-二聚体水平差异不具有统计学意义(P0.05)。当以D-二聚体0.85μg/L为PJI诊断标准时,血清CRP、ESR、D-二聚体诊断PJI的敏感性、特异性类似,差异无统计学意义(P0.05)。当以D-二聚体0.5μg/L为PJI诊断标准时,D-二聚体诊断PJI的敏感性与CRP及ESR类似(P0.05),但特异性差于CRP及ESR,差异具有统计学意义(P0.05)。[结论]与CRP、ESR相比,血清D-二聚体在PJI诊断中无明显优势。     

假体周围感染诊断新检验指标的探讨

[目的]探讨血小板计数(platelet, PLT)和平均血小板体积(mean platelet volume, MPV)比值(PLT/MPV)及纤维蛋白原(fibrinogen, FIB)在关节假体周围感染(periprosthetic joint infection, PJI)诊断中的意义。[方法]回顾性分析本科2017年6月1日—2018年12月31日收治的110例患者的临床资料。根据临床诊断将患者分为三组,初期置换组39例;感染翻修组42例;松动翻修组29例。记录三组术前CRP,ESR,PLT/MPV,FIB等数据。[结果]感染翻修组患者的术前CRP、ESR、FIB、PLT/MPV均显著高于初期置换组和松动翻修组(P0.05)。而初期置换组与松动翻修组间CRP、ESR、FIB、PLT/MPV间的差异均无统计学意义(P0.05)。按照传统CRP和ESR诊断PJI临界值,PLT/MPV31.70及血浆FIB4.01μg/ml为PJI诊断的临界值,诊断的敏感性由高至低依次为:FIBESRCRPPLT/MPV,四项指标间的敏感性差异有统计学意义(P0.05);其中PLT/MPV的敏感性显著低于FIB、ESR和CRP (P0.05);而FIB、ESR和CPR间敏感性的差异无统计学意义(P0.05)。诊断特异性由高至低依次为:CRPESR=FIBPLT/MPV,但各指标间特异性的差异均无统计学意义(P0.05)。[结论] PLT/MPV不应作为PJI诊断的首选辅助指标,血浆FIB可作为PJI诊断的新辅助指标。     

系统免疫炎症指数和全身炎性反应指数对诊断关节假体周围感染的价值研究

目的探讨全身免疫炎症指数(SII)和全身炎性反应指数(SIRI)单独及联合ESR、CRP对关节假体周围感染(PJI)的诊断价值。方法研究2017年4月至2021年4月期间在河南省人民医院行髋、膝关节翻修术的139例患者, 64例纳入PJI组, 75例纳入假体无菌性松动组。收集两组患者ESR、CRP、SII以及SIRI的临床资料信息, 绘制各项指标的受试者工作特征(ROC)曲线, 并根据约登指数确定各指标的最佳截断值, 灵敏度、特异度比较其诊断效能。两组比较采用t检验、Mann-WhitneyU检验。结果 PJI组和假体无菌性松动组患者在性别、年龄方面差异均无统计学意义(P>0.05)。PJI组ESR、CRP、SII、SIRI指标高于无菌性松动组[53.50(35.50, 78.50) mm/h比16.00(7.00, 32.00) mm/h, Z=-7.012, P<0.05;24.91(9.48, 54.75) mg/L比2.00(0.80, 7.80) mg/L, Z=-7.007, P<0.05;681.13(446.94, 1 142.05)比374.98(2...     

采用红细胞沉降率和C-反应蛋白作为假体周围感染的阈值

肌肉骨骼感染协会推荐的红细胞沉降率(ESR)和C-反应蛋白(CRP)作为假体周围感染的阈值为30 mm/1 h和10 mg/L。为验证其有效性,作者分析了81例假体周围感染(PJI)和83例非PJI患者资料。结果发现ESR达到敏感性高于95%的阈值为10 mm/1 h,CRP达到敏感性高于95%的阈值为5 mg/L。联合ESR阈值为10 mm/1 h和CRP阈值为5 mg/L的敏感性达到100%,特异性为54.7%。因此作者认为,以ESR阈值为30 mm/1 h和CRP阈值为10 mg/L作为标准筛查PJI的敏感性太低,假阴性率太高,建议降低两者的筛查阈值。     

二代测序技术在诊断假体周围感染中的应用

[目的]探讨二代测序技术在关节置换术后假体周围感染诊断中的应用价值。[方法]选取2018年1月～2018年12月在本院就诊的人工关节置换术后关节疼痛、红肿、怀疑假体周围感染的患者。依据美国肌肉、骨骼感染病学会(MSIS)诊断标准,最终共计22例患者确诊为人工关节置换术后假体周围感染。其中男10例,女12例;膝关节感染16例,髋关节感染6例。所有22例PJI患者均行关节液二代测序和细菌培养。分别记录二代测序及细菌培养结果,以检测或培养出微生物为阳性,未检测或培养出微生物为阴性,记录阳性例数。分别计算二代测序技术和细菌培养在PJI患者中的阳性检出率以及在髋膝不同部位的阳性检出率,并通过配对卡方检验进行统计学分析。[结果]总计22例PJI患者中,18例患者二代测序检出微生物,二代测序在PJI患者中的阳性检出率为18/22(81.82%);关节液细菌培养阳性9例,关节液细菌培养在PJI患者中的阳性检出率为9/22(40.91%)。配对卡方检验提示两种方法在PJI患者中的检出率差异有统计学意义(P=0.022)。[结论]二代测序技术在PJI患者的诊断中具有更高的细菌检出率,在PJI患者病原微生物学检查中有更大的诊断价值。     

血清学炎性因子在假体周围感染中的应用

目的通过检测由于各种原因接受关节翻修手术患者血清中C-反应蛋白(CRP)、动态红细胞沉降率(ESR)、超敏C-反应蛋白(hs-CRP)及白细胞介素-6(IL-6),探讨其在诊断假体周围感染中的临床意义与诊断价值。方法选取2013年8月至2016年8月于北京大学人民医院骨关节科接受关节翻修手术的患者160例,符合美国肌肉与骨骼肌感染协会(MSIS)制定的假体周围感染诊断标准的患者为感染组,不符合者为非感染组,测量患者的血清中CRP、ESR、hs-CRP及IL-6水平,并通过受试者工作特征曲线-曲线下面积(ROC-AUC)分析评估各指标诊断假体周围感染的临床意义与价值。结果血清学炎性指标CRP、ESR、hs-CRP及IL-6水平感染组较非感染组高(P0.01),其AUC值为0.89(95%CI:0.83,0.94)、0.88(95%CI:0.82,0.93)、0.90(95%CI:0.84,0.95)及0.92(95%CI:0.89,0.96)。各指标之间无明显统计学差异。IL-6与CRP或hs-CRP平行试验联合诊断PJI敏感性高(敏感性分别为100.0%(93.9%,100.0%)和98.3%(90.9%,100.0%)),具有很好的应用价值。结论 CRP、ESR、hs-CRP和IL-6对于假体周围感染具有明确的诊断意义,其中IL-6的诊断价值可能更高。联合诊断能提高假体周围感染诊断的敏感性或者特异性。CRP与IL-6联合或者hs-CRP与IL-6联合对于排除假体周围感染临床意义更大。     

宏基因组二代测序技术在假体周围感染病原诊断中的应用

目的探讨基于假体周围组织的宏基因组二代测序技术(metagenomic next-generation sequencing,mNGS)在关节置换术后假体周围感染(periprosthetic joint infection,PJI)的诊断效率和价值。方法回顾性分析2019年6月至2020年6月接受髋或膝关节翻修术33例患者的病历资料。诊断为PJI的病例设为感染组共21例,男9例,女12例;年龄(59.14±14.55)岁(范围:28~84岁);膝关节17例,髋关节4例;体质指数(body mass index,BMI)为(23.7±2.8)kg/m²(范围:17.7~29.4 kg/m²)。诊断为假体无菌性松动的病例设为对照组共12例,男4例,女8例;年龄为(53.08±10.05)岁(范围:39~70岁);膝关节4例,髋关节8例;BMI为(25.2±2.9)kg/m²(范围:18.3~31.2 kg/m²)。收集所有病例关节液和组织微生物培养的结果,收集所有病例mNGS检测假体周围组织的结果。比较微生物培养和mNGS检测对膝或髋关节PJI诊断的敏感性和特异性,总结和比较两种技术检出致病菌的种类,比较取样前2周内抗生素的使用对两种技术检出率的影响。结果感染组21例中mNGS共检出13例阳性,微生物培养共检出6例阳性。对照组12例中mNGS仅检出1例阳性,微生物培养结果均为阴性。在PJI的诊断中,mNGS敏感性(61.9%)与微生物培养(28.6%)的差异有统计学意义(χ2=4.71,P=0.03);mNGS特异性(91.7%)与微生物培养(100%)的差异无统计学意义(χ2=1.04,P=0.31)。在2周内有抗生素暴露的PJI病例中,mNGS阳性率(53.8%)明显高于微生物培养(15.4%),差异有统计学意义(χ2=4.25,P=0.04);而在2周内无抗生素暴露的PJI病例中,mNGS阳性率(66.7%)与微生物培养(44.4%)的差异无统计学意义(χ2=0.90,P=0.34)。在致病菌检出上,mNGS共检出9种细菌(金黄色葡萄球菌、科氏葡萄球菌、奥斯陆莫拉菌、痤疮丙酸杆菌、毗邻颗粒链菌、表皮葡萄球菌、结核分枝杆菌、里昂葡萄球菌、脆弱拟杆菌)和2种真菌(烟曲霉菌、近平滑念珠菌);微生物培养共检出3种细菌(金黄色葡萄球菌、卡他莫拉菌、结核分枝杆菌)和1种真菌(近平滑念珠菌)。mNGS和微生物培养均为阳性的患者共5例,3例检出完全一致的致病菌(金黄色葡萄球菌、结核分枝杆菌、近平滑念珠菌),1例部分一致(mNGS检出更多致病菌),1例完全不同。另外,mNGS在3例结核性PJI的诊断中表现出100%的特异性和敏感性,优于微生物培养。结论基于假体周围组织的mNGS检测技术是诊断PJI和确定致病菌的有效手段。取样前抗生素暴露对mNGS技术检出效力的影响小于微生物培养。     

血清学指标诊断慢性假体周围感染的性别差异

目的探讨血清C反应蛋白(C-reactive protein, CRP)、红细胞沉降率(erythrocyte sedimentation rate, ESR)、血小板(platelet, PLT)、纤维蛋白原(fibrinogen, FIB)及D-二聚体诊断慢性假体周围感染(periprosthetic joint infection, PJI)的性别差异。方法回顾性分析2013年1月至2021年12月新疆医科大学第一附属医院关节外科收治的470例接受人工关节翻修的患者, 根据性别及疾病诊断分为四组:男性慢性PJI组78例、男性无菌性松动组108例、女性慢性PJI组95例、女性无菌性松动组189例。收集患者术前CRP、ESR、PLT、FIB及D-二聚体等血清学结果。采用受试者工作特征(receiver operating characteristics, ROC)曲线确定CRP、ESR、PLT、FIB及D-二聚体诊断不同性别的慢性PJI的最佳截断值, 并计算其灵敏度及特异度。通过比较不同指标的曲线下面积(area under curve, AUC)分析该指标的诊断效能。结果男性慢性P...     

初次置换术前血清胆红素与假体周围感染的相关研究

[目的]探究初次关节置换术前血清胆红素水平与髋、膝关节置换术后发生关节假体周围感染(periprosthetic joint infection, PJI)的相关性。[方法]回顾性分析2016年1月—2018年12月在解放军总医院第一医学中心骨科行髋、膝关节置换术后翻修患者,共纳39例患者纳入本研究。依据PJI诊断标准,22例为PJI,17例为非PJI组。收集患者一般资料,以及初次关节置换术前血生化、血常规、CRP、IL-6、ESR、D-二聚体等实验室检测指标,比较两组患者间各单项因素,采用ROC曲线分析初次关节置换术前血清总胆红素和直接胆红素诊断PJI的价值。[结果]两组在年龄、性别构成、体质指数、部位、是否吸烟、是否糖尿病、是否冠心病方面的差异均无统计学意义(P0.05)。但是PJI组的初次置换至翻修手术间隔时间显著短于非PJI组(P0.05)。初次关节置换术前总胆红素PJI组显著低于非PJI组[(11.00±0.95)μmol/L vs (15.02±1.12)μmol/L,P0.05],初次关节置换术前直接胆红素PJI组显著低于非PJI组[(3.36±0.28)μmol/L vs (4.87±0.68)μmol/L,P0.05];两组患者其余的术前化验指标之间差异均无统计学意义(P0.05)。初次关节置换术前总胆红素预测PJI的AUC=0.729,P=0.015,Cutoff=13.05μmol/L,敏感度=68.18%,特异度=70.59%;初次关节置换术前直接胆红素预测PJI的AUC=0.683,P=0.049,Cutoff=4.00μmol/L,敏感度=77.27%,特异度=58.82%。[结论]初次关节置换术前血清总胆红素和直接胆红素水平PJI患者均显著低于非PJI患者,此两指标有可能用于预测PJI。     

Differing Microorganism Profile in Early and Late Prosthetic Joint Infections Following Primary Total Knee Arthroplasty — Implications for Empiric Antibiotic Treatment

BackgroundProsthetic joint infection (PJI) is the leading cause of revision following total knee arthroplasty (TKA). Prior to microorganism identification, the choice of the correct empiric antibiotics is critical to treatment success. This study aims to 1) compare the microorganism and resistance profile in early and late PJIs; 2) recommend appropriate empiric antibiotics.MethodsA multicentre retrospective review was performed over a 15-year period. First episode PJIs were classified by both the Tsukayama Classification and Auckland Classification. For each PJI case, the causative organism and antibiotic sensitivity were recorded.ResultsOf eligible patients, 232 culture-positive PJI cases were included. Using either classification system, early PJIs (<4 weeks or <1 year since primary) were significantly more likely to be resistant and polymicrobial. The predominant organisms were coagulase-negative Staphylococci in early PJIs while Staphylococcus aureus was the most common in late PJIs. The distribution of gram-negative cases was higher in early Class-A than late Class-C PJIs (25% versus 6%, P = .004). Vancomycin provided significantly superior coverage when compared to Flucloxacillin for early infections, and addition of a gram-negative agent achieved coverage over 90% using both classification systems.ConclusionBased on the microbiological pattern in Tsukayama criteria, Vancomycin with the consideration of Gram-negative agent should be considered for Class-A infections given the high proportion of resistant and polymicrobial cases. For Class-C infections, Cephazolin or Flucloxacillin is likely sufficient. We recommend antibiotics to be withheld in Class-B infections until cultures and sensitivities are known.     

Elevated ESR/CRP Ratio Is Associated With Reinfection After Debridement,Antibiotics, and Implant Retention in Chronic Periprosthetic Joint Infections

BackgroundRatios of established inflammatory markers, erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), have been used for diagnostic purposes in the surgical field; however, the ESR:CRP ratio (ECR) has not been evaluated as a marker for predicting infection resolution in patients with periprosthetic joint infections (PJIs). This study aimed to evaluate the diagnostic accuracy of ECR in predicting postoperative reinfection in patients who underwent debridement, antibiotics, and implant retention (DAIR).MethodsThis is a retrospective review of 179 consecutive patients who underwent DAIR revision total joint arthroplasty for PJI. Patients were stratified by acuity of their infection: acute PJI, acute hematogenous PJI, and chronic PJI. The area under the receiver operating characteristic curve was calculated to evaluate ECR as diagnostic marker for predicting postoperative reinfection in patients who underwent DAIR.ResultsStatistically significant differences in ECR were found in patients who underwent DAIR revision total joint arthroplasty for chronic infection (1.23 vs 2.33; P = .04). There was no significant difference in ECR in patients who underwent DAIR for acute infection (P = .70) and acute hematogenous infection (P = .56). In patients who underwent DAIR for chronic PJI, ECR demonstrated a sensitivity and specificity of 75% and 84%, respectively, for the prediction of postoperative reinfection, which was significantly higher than that of ESR (sensitivity, 67%; specificity, 47%; P < .001) and CRP (sensitivity, 50%; specificity, 26%; P < .001).ConclusionElevated ECR was associated with an increased reinfection risk in patients who underwent DAIR for chronic PJI, suggesting that preoperative ECR may be a useful predictor to identify patients at increased risk of reinfection after DAIR for chronic PJIs.     

The 2018 Definition of Periprosthetic Hip and Knee Infection: An Evidence-Based and Validated Criteria

Background

The introduction of the Musculoskeletal Infection Society (MSIS) criteria for periprosthetic joint infection (PJI) in 2011 resulted in improvements in diagnostic confidence and research collaboration. The emergence of new diagnostic tests and the lessons we have learned from the past 7 years using the MSIS definition, prompted us to develop an evidence-based and validated updated version of the criteria.

基因二代测序技术在假体周围感染诊断中的价值

目的通过与细菌培养及血清生物学标志对比,探讨二代测序技术(NGS)对人工关节置换术后假体周围感染(PJI)的诊断价值。 方法选取2017年7月到2019年12月在聊城市人民医院关节外科因假体周围感染或无菌性松动行关节翻修手术,排除初始关节液无法采集到,通过关节内注射生理盐水获得样本的患者及其他部位存在感染病灶的患者,共纳入患者35人(35例)根据美国肌骨骼感染协会(MSIS)的诊断标准,15例患者纳入感染组,20例患者纳入非感染组。术前两组患者常规检查血沉(ESR)、C反应蛋白(CRP)、降钙素原(PCT)、白介素6(IL-6)及D-二聚体(D-Dimer)。所有患者术前均行关节穿刺,穿刺液检测白细胞计数、白细胞分类、细菌培养及NGS。计算ESR、CRP、PCT、IL-6及D-Dimer的受试者操作特性曲线(ROC)的曲线下面积(AUC)。计算NGS、细菌培养及各项血清学标志物的诊断精确度、敏感性及特异性。 结果髋关节19例(54.3%),膝关节16例(45.7%)。男性21例(60.0%),女性14例(40.0%),年龄67.0(62.0,74.0)岁。感染组15例患者中NGS结果阳性14例(93.3%),细菌培养结果阳性7例(46.7%)。非感染组NGS结果阴18例(90.0%)。ESR及D二聚体的AUC分别为0.667和0.572(均为P>0.05)。CRP、IL-6及PCT的AUC分别为0.827、0.767及0.808(均为P<0.01)。NGS、细菌培养、CRP、IL-6及PCT的精确度分别为0.91、0.74、0.77、0.74及0.83。NGS与CRP、IL-6、PCT、细菌培养两两比较,总体检测结果差异有统计学意义(P<0.01)。NGS与CRP、IL-6、PCT、细菌培养两两比较,NGS敏感性更高(P<0.05)。NGS与CRP比较特异性更好(P<0.05)。NGS与IL-6、PCT及细菌培养比较,特异性差异无统计学意义(P>0.05)。 结论NGS比细菌培养及常用的血清学标志物有更高的精确度及敏感性,在PJI的诊断中具有更大的价值。     

Applying the new shoulder periprosthetic joint infection consensus definition to a case series of revision shoulder arthroplasty procedures to assess concordance between consensus definitions and diagnoses

PurposeAs the number of shoulder arthroplasty procedures performed rises yearly, so does the number of periprosthetic joint infections (PJIs). In this study, PJI consensus definitions were compared and contrasted in a series of revision shoulder arthroplasty cases preoperatively diagnosed as PJI. Understanding the variations in these definitions may guide PJI diagnoses, thereby improving treatment strategies and patient outcomes in the setting of infected shoulder arthroplasty.MethodsAll revision shoulder arthroplasty cases with preoperatively-diagnosed or suspected PJI (determined by procedure code) performed from 2008 – 2017 at a single institution by a single surgeon (fellowship-trained in shoulder and elbow surgery) were retrospectively evaluated. Following Institutional Review Board approval, patient demographic, treatment, and laboratory data were collected. Musculoskeletal Infection Society (MSIS; 2011) and International Consensus Meeting on Orthopaedic Infections (ICM; 2013, 2018 Revision, 2018 Shoulder) definitions of PJI were applied to the data. Statistical analysis assessed significant associations between culture status and PJI classification algorithm criteria.ResultsThirty-seven patients with suspected PJI were identified; 24 culture-positive (CP) and 13 culture-negative (CN). In this series, the 2018 ICM Shoulder definition for definite infection was met at lower rates than all other definitions (CP; 71% vs. 96%; CN; 62% vs. 69%). 2018 ICM Shoulder major criteria showed stronger correlations to 2011 MSIS, 2013 ICM, and 2018 ICM Revision major criteria when “gross intra-articular pus” was excluded than when pus was included as a major criterion. 2018 ICM Revision cases determined to be infected were very strongly, positively, correlated with the 2018 ICM Shoulder cases determined to have definite or probable infections (ρ = 1.000, P < .0001). Additionally, cases classified as “definite” or “probable” infections with the 2018 ICM Shoulder definition were more likely to require reoperation for suspected recurrent infection after completion of antibiotic therapy.ConclusionsIn this series, the 2018 ICM Shoulder definition and previous PJI definitions classified cases as PJI at similar rates. However, the inclusion of a third major criterion of “gross intra-articular pus” weakened the correlation with prior definitions.Level of evidenceLevel IV; Case Series.     

Efficacy of a novel PCR- and microarray-based method in diagnosis of a prosthetic joint infection

Background and purpose

Polymerase chain reaction (PCR) methods enable detection and species identification of many pathogens. We assessed the efficacy of a new PCR and microarray-based platform for detection of bacteria in prosthetic joint infections (PJIs).

Methods

This prospective study involved 61 suspected PJIs in hip and knee prostheses and 20 negative controls. 142 samples were analyzed by Prove-it Bone and Joint assay. The laboratory staff conducting the Prove-it analysis were not aware of the results of microbiological culture and clinical findings. The results of the analysis were compared with diagnosis of PJIs defined according to the Musculoskeletal Infection Society (MSIS) criteria and with the results of microbiological culture.

Results

38 of 61 suspected PJIs met the definition of PJI according to the MSIS criteria. Of the 38 patients, the PCR detected bacteria in 31 whereas bacterial culture was positive in 28 patients. 15 of the PJI patients were undergoing antimicrobial treatment as the samples for analysis were obtained. When antimicrobial treatment had lasted 4 days or more, PCR detected bacteria in 6 of the 9 patients, but positive cultures were noted in only 2 of the 9 patients. All PCR results for the controls were negative. Of the 61 suspected PJIs, there were false-positive PCR results in 6 cases.

Interpretation

The Prove-it assay was helpful in PJI diagnostics during ongoing antimicrobial treatment. Without preceding treatment with antimicrobials, PCR and microarray-based assay did not appear to give any additional information over culture.Of the patients with a total hip or knee arthroplasty, 1–2% suffer from a prosthetic joint infection (PJI) (Blom et al. 2004, Kurtz et al. 2012). Diagnosis of a PJI is often a challenge. To successfully cure a PJI, an exact microbiological diagnosis is crucial. All the contemporary investigation methods have their own strengths and weaknesses.Polymerase chain reaction (PCR) can be faster than the time-consuming traditional culture of bacteria. The novel Prove-it Bone and Joint assay can provide results in 6 hours, including the time required for sample preparation. The Prove-it PCR and microarray-based platform, targeted for over 60 bacterial species, has proven to be faster in identifying bacterial species in positive blood cultures than the conventional culture-based methods in sepsis diagnostics. Clinical sensitivity and specificity in blood cultures have been high, 95% and 99% (Tissari et al. 2010).We investigated whether the novel broad-range PCR and microarray-based platform efficiently detects bacterial infections in suspected PJIs and whether it offers advantages over routine culture.     

Utility of Diagnostic Markers in Late Periprosthetic Joint Infection Workup for Total Knee Arthroplasty Patients Who Received Antibiotics 48 Hours Before Aspiration

BackgroundDiagnosing periprosthetic joint infection (PJI) following total knee arthroplasty (TKA) remains challenging despite recent advancements in testing and evolving criteria over the last decade. Moreover, the effects of antibiotic use on diagnostic markers are not fully understood. Thus, this study sought to determine the influence of antibiotic use within 48 hours before knee aspiration on synovial and serum laboratory values for suspected late PJI.MethodsPatients who underwent a TKA and subsequent knee arthrocentesis for PJI workup at least 6 weeks after their index arthroplasty were reviewed across a single healthcare system from 2013 to 2020. Median synovial white blood cell (WBC) count, synovial polymorphonuclear (PMN) percentage, serum erythrocyte sedimentation rate (ESR), serum C-reactive protein (CRP), and serum WBC count were compared between immediate antibiotic and nonantibiotic PJI groups. Receiver operating characteristic (ROC) curves and Youden’s index were used to determine test performance and diagnostic cutoffs for the immediate antibiotics group.ResultsThe immediate antibiotics group had significantly more culture-negative PJIs than the no antibiotics group (38.1 versus 16.2%, P = .0124). Synovial WBC count demonstrated excellent discriminatory ability for late PJI in the immediate antibiotics group (area under curve, AUC = 0.97), followed by synovial PMN percentage (AUC = 0.88), serum CRP (AUC = 0.86), and serum ESR (AUC = 0.82).ConclusionAntibiotic use immediately preceding knee aspiration should not preclude the utility of synovial and serum lab values for the diagnosis of late PJI. Instead, these markers should be considered thoroughly during infection workup considering the high rate of culture-negative PJI in these patients.Level of EvidenceLevel III, retrospective comparative study.     

The Leukocyte Esterase Strip Test has Practical Value for Diagnosing Periprosthetic Joint Infection After Total Knee Arthroplasty: A Multicenter Study

Background

Leukocyte esterase (LE) was recently reported to be an accurate marker for diagnosing periprosthetic joint infection (PJI) as defined by the Musculoskeletal Infection Society (MSIS) criteria. However, the diagnostic value of the LE test for PJI after total knee arthroplasty (TKA), the reliability of the subjective visual interpretation of the LE test, and the correlation between the LE test results and the current MSIS criteria remain unclear.

Sonication of Arthroplasty Implants Improves Accuracy of Periprosthetic Joint Infection Cultures

Background

There is evidence that sonication of explanted prosthetic hip and knee arthroplasty components with culture of the sonication fluid may enhance diagnostic sensitivity. Previous studies on the use of implant sonicate cultures have evaluated diagnostic thresholds but did not elaborate on the clinical importance of positive implant sonicate cultures in the setting of presumed aseptic revisions and did not utilize consensus statements on periprosthetic joint infection (PJI) diagnosis when defining their gold standard for infection.

Questions/purposes

(1) How do implant sonicate cultures compare with preoperative synovial fluid cultures and intraoperative tissue cultures in the diagnosis of PJI in both THA and TKA when compared against Musculoskeletal Infection Society (MSIS) criteria for PJI? (2) Utilizing implant sonicate cultures, what is the relative prevalence of bacterial species identified in PJIs? (3) What is the incidence of positive implant sonicate cultures in the setting of presumed aseptic revision hip and knee arthroplasty procedures, and what treatments did they receive?

Methods

Between 2012 and 2016 we performed implant sonicate fluid cultures on surgically removed implants from 565 revision THAs and TKAs. Exclusion criteria including insufficient data to determine Musculoskeletal Infection Society (MSIS) classification, fungal-only cultures, and absence of reported colony-forming units decreased the number of procedures to 503. Procedures represented each instance of revision surgery (sometimes multiple in the same patient). Of those, a definitive diagnosis of infection was made using the MSIS criteria in 178 of 503 (35%), whereas the others (325 of 503 [65%]) were diagnosed as without infection. A total of 53 of 325 (16%) were considered without infection based on MSIS criteria but had a positive implant sonicate culture. Twenty-five of 53 (47%) of these patients were followed for at least 2 years. The diagnosis of PJI was determined using the MSIS criteria.

Results

Sensitivity of implant sonicate culture was greater than synovial fluid culture and tissue culture (97% [89%–99%] versus 57% [44%–69%], p < 0.001; 97% [89%–99%] versus 70% [58%–80%], p < 0.001, respectively). The specificity of implant sonicate culture was not different from synovial fluid culture or tissue culture with the numbers available (90% [72%–97%] versus 100% [86%–100%], p = 0.833; 90% [72%–97%] versus 97% [81%–100%], p = 0.317, respectively). Coagulase-negative Staphylococcus was the most prevalent organism for both procedure types. In PJIs, the five most frequent bacteria identified by synovial fluid, tissue, and/or implant sonicate cultures were coagulase-negative Staphylococcus (26% [89 of 267]), methicillin-susceptible Staphylococcus aureus (19% [65 of 267]), methicillin-resistant S. aureus (12% [43 of 267]), α-hemolytic Streptococci (5% [19 of 267]), and Enterococcus faecalis (5% [19 of 267]). Fifty-three of 325 (16%) presumed aseptic revisions had a positive sonication culture. Thirty-four percent (18 of 53) of culture-positive aseptic revision patients received antibiotic treatment for infection and 8% (4 of 53) underwent a secondary revision.

Conclusions

The routine use of implant sonicate cultures in arthroplasty revisions improves the diagnostic sensitivity for detecting the presence of bacteria in both clinical and occult infections. Future studies will need to refine colony-forming unit thresholds for determining clinical infection and indications for treatment.

Level of Evidence

Level III, diagnostic study.

     

How Does a “Dry Tap” Impact the Accuracy of Preoperative Aspiration Results in Predicting Chronic Periprosthetic Joint Infection?

BackgroundPeriprosthetic joint infection (PJI) after total hip arthroplasty (THA) is challenging to diagnose. We aimed to evaluate the impact of dry taps requiring saline lavage during preoperative intra-articular hip aspiration on the accuracy of diagnosing PJI before revision surgery.MethodsA retrospective review was conducted for THA patients with suspected PJI who received an image-guided hip aspiration from May 2016 to February 2020. Musculoskeletal Infection Society (MSIS) diagnostic criteria for PJI were compared between patients who had dry tap (DT) vs successful tap (ST). Sensitivity and specificity of synovial markers were compared between the DT and ST groups. Concordance between preoperative and intraoperative cultures was determined for the 2 groups.ResultsIn total, 335 THA patients met inclusion criteria. A greater proportion of patients in the ST group met MSIS criteria preoperatively (30.2% vs 8.3%, P < .001). Patients in the ST group had higher rates of revision for PJI (28.4% vs 17.5%, P = .026) and for any indication (48.4% vs 36.7%, P = .039). MSIS synovial white blood cell count thresholds were more sensitive in the ST group (90.0% vs 66.7%). There was no difference in culture concordance (67.9% vs 65.9%, P = .709), though the DT group had a higher rate of negative preoperative cultures followed by positive intraoperative cultures (85.7% vs 41.1%, P = .047).ConclusionOur results indicate that approximately one third of patients have dry hip aspiration, and in these patients cultures are less predictive of intraoperative findings. This suggests that surgeons considering potential PJI after THA should apply extra scrutiny when interpreting negative results in patients who require saline lavage for hip joint aspiration.