全膝关节置换术后感染的预防和治疗

InfectionFollowingTotalKneeArthroplasty:PreventionandManagement

全膝关节置换术后感染的预防和治疗

KevinL.Garvin,MD,andBeauS.Konigsberg,MD

AnInstructionalCourseLecture,AmericanAcademyofOrthopaedicSurgeons

Periprostheticjointinfectionisoneofthemostformidablechallengesforarthroplastysurgeons.Physiciansandscientistshaveworkeddiligentlytolowertheincidenceofinfectionsaroundprostheticjoints,butthepercentageofpatientswhodevelopaninfectionafterprimarytotalkneereplacementremainsintherangeof0.4%to2%1-3.Medicaredataindicatethattherateofperiprostheticinfectionwithinthefirsttwoyearsafterkneearthroplastyis1.55%.Theinfectionrateinthefollowingtwototenyearsisanadditional0.46%4,5.

关节假体周围感染是关节外科医师所面临的最严峻的挑战之一。尽管医生和科学家们一致努力降低关节假体周围感染的发病率，但初次全膝关节置换术后发生感染的患者的比例仍有0.4%-2%。医疗数据显示，关节假体周围感染在膝关节置换术后前2年的发生率为1.55%，而之后的2-10年的发生率增加0.46%。

Whilethepercentageofprosthetickneesthatareassociatedwithinfectionislow,thenumberswillincreasewiththegrowingnumberoftotalkneereplacements.Kjectedthatthedemandforprimarykneearthroplastywillgrowby673%,from450,000in2005to3.48millionin20306.If2%ofthe3.48millionpatientsdevelopaninfectionwithinthefirstyearafterthekneearthroplasty,asmanyas69,000patientsmaybetreatedforperiprosthetickneeinfectioneachyear.Thisgroupdoesnotincludepatientswhodevelopaninfectionmorethanoneyearafterthesurgeryorafterarevisiontotalkneearthroplasty.Theburdenandcomplexityarealsoincreasingbecauseofthenumberofresistantpathogens.

然而与膝关节假体相关的感染的发生率较低，感染的例数随着全膝关节置换的数量增加而增加。Kurtz等曾经预测需要行初次全膝关节置换的病例数将会从2005年的450，000例增加到2030年的348万例，增加673%。如果348万例患者有2%在膝关节置换术后第1年发生感染，每年大约会有69，000例患者会因膝关节假体周围感染而进行治疗。这些还不包括术后1年以后或者膝关节翻修术后发生感染的患者。因为耐药菌的产生，患者的负担和疾病的复杂性也相应增加了。

Staphylococcusaureusaccountsforthemajorityofperiprostheticjointinfections.Infectionscausedbymethicillin-resistantStaphylococcusaureus(MRSA)areespeciallydifficulttotreat7-9.TheStaphylococcusinfectionsmaybeacquiredinthehospital,butsomepatientsareknowncarriersofStaphylococcusaureusandinfectthemselves10,11.Patientswhoarecarrierscanbescreenedanddecolonizationcanbecarriedoutpreoperatively,potentiallyloweringtheriskofperiprostheticjointinfection.

金黄色葡萄球菌感染占关节假体周围感染的大多数。尤其是耐甲氧酸西林金黄色葡萄球菌（MRSA）感染更难治疗。葡萄球菌感染可能是医学获得性感染，但一些患者是金黄色葡萄球菌携带者，为自身感染。病原菌携带者可以进行筛选，并在术前进行治疗，可以降低关节假体周围感染的风险。

Prevention

预防

Avarietyofinterventionscanreducetheincidenceofinfections.Priortosurgery,surgeonsshouldidentifyandaddresshostfactorsassociatedwithanincreasedrisk,carryoutdecolonizationwhenapatientisabacterialcarrier,anduseperioperativeantibiotics.Prophylacticantibioticsareeffectiveinpreventingsurgicalsiteinfections.Theprotocolshouldbetoadministertheantibioticsonehourbeforethesurgicalincisionismade.Rosenbergetal.reportedthat,inathree-monthintervalbeforetheinitiationofaprotocoltoensurecompliancewithantibioticdosing,onlytwenty-six(65%)offortypatientsreceivedprophylacticantibioticswithinonehourbeforetheincision12.Aftertheprotocolwasstarted,thecomplianceincreasedto180(97%)of186patients(p<0.0001).TheAmericanAcademyofOrthopaedicSurgeons(AAOS)haspublishedguidelinesforthemostappropriateantibiotics13-15.Cefazolinandcefuroximearepreferred,withclindamycinorvancomycinbeingrecommendedforpatientswithbeta-lactamallergies.VancomycinmayalsobeusedforpatientswhoarehavingsurgeryinaninstitutionwheretheprevalenceofMRSAorMRSE(methicillin-resistantStaphylococcusepidermidis)intheorthopaedicpatientsis>25%.

有多种干预方法能够降低感染的发生率。术前，医生应当确定并解决增加感染的主要危险因素，当患者为病原菌携带者时应当使用抗生素进行抗菌治疗。预防性使用抗生素对预防手术部位感染是有效的，通常在手术开始前1小时给予。Rosenberg等报道指出，在这种方案实施前3个月间，为确认与抗生素剂量一致，40例患者中，仅有26例（65%）在术前1小时预防性使用了抗生素。该治疗方案开始实施后，执行力得到提高，186例患者中有180例（97%）术前预防性使用了抗生素(p<0.0001)。美国骨科医师学会（AAOS）已经出版了最适用抗生素使用指南，首选头孢唑啉和头孢呋辛，对β-内酰胺类过敏者使用克林霉素或万古霉素。万古霉素也可用于骨科患者MRSA或MRSE发病率＞25%的机构进行手术的患者。

PatientscolonizedwithMRSAorso-calledcarriersoftheseresistantpathogensarealsocandidatesfortreatmentwithvancomycin.Thesepatientsalsoshouldreceiveadditionaltreatmentincludingchlorhexidinegluconatescrubsandnasalmupirocin.Thedecolonizingprotocolshavedemonstratedtheabilitytoreducetherateofstaphylococcalinfections.StudieshavealsoshownthatadecolonizingprotocoliseffectiveineradicatingMRSAcolonizationofpatients8,16-19

感染MRSA的患者或所谓的耐药菌携带者也是使用万古霉素治疗的对象，这些患者还应当接受洗必泰擦洗和鼻部喷莫匹罗星等辅助治疗。清除病原菌的治疗方案已经证明能够降低葡萄球菌感染的发生率。研究还表明，这种治疗方案在根除患者体内MRSA方面效果显著。

HostRiskFactors

主要危险因素

Periprostheticjointinfectionhasbeenassociatedwithanumberofhostriskfactors,includingmalnutrition,smoking,alcoholism,urinarytractinfection,andobesity(TableI).Inaretrospectivereviewthatincluded6108patientswhohadundergoneatotalof8494hiporkneearthroplastiesbetween1991and2004,Mparedthosewhohaddevelopedadeepinfectionwithanon-infectedcontrolgroup20.Theyfoundforty-threedeepinfections(thirtyassociatedwithtotalkneearthroplastyandthirteen,withtotalhiparthroplasty),foraprevalenceof0.51%.Obesity,youngerage,anddiabetesmellituswereidentifiedassignificantriskfactorsforinfection.Morbidlyobesepatients(thosewithabody-massindex[BMI]of>50kg/m2)hadanincreasedoddsofdevelopinginfection(oddsratio,21.3).Inthegrouptreatedwithtotalkneearthroplasty,patientswhohadaBMIof>40but<50kg/m2had3.3timesgreateroddsofdevelopinganinfectioncomparedwiththosewithaBMIof<40kg/m2.Theaverageageofthepatientswithaninfectedkneewas62.8years,andtheaverageageofthosewithoutaninfectedkneewas69.2years.Patientswithdiabetesmellituswere3.1timesmorelikelytodevelopadeepinfectionthanwerethosewithoutdiabetes.Additionalstudieshaveshownaclinicallyrelevantbenefittomaintainingstrictglycemiccontrolindiabeticpatientsintheperioperativeperiod21.Mparedagroupofpatientswithwell-controlleddiabeteswithagroupwithpoorlycontrolleddiabeteswhentheyunderwenttotalkneearthroplastyandfoundtheoddsofdevelopingawoundinfectiontobeincreasedinthegroupwithpoorlycontrolleddiabetes(oddsratio,2.28)21.Bolognesietal.reviewedtheNationalInpatientSample(NIS)recordsof751,340primaryandrevisionhipandkneereplacements,including64,239indiabetics,andfoundnoincreaseininfectioninthediabeticpopulation22.However,thisfindingislikelyduetothefactthattheNISwasnotdesignedtocollectdataoncomplicationsaftertheinitialhospitalstayandisnotlikelytoincludethegreatmajorityofperiprostheticjointinfections.

关节假体周围感染与以下主要因素有关：营养不良、抽烟、酗酒、尿路感染及肥胖（表1）。1991年至2004年，6108例患者共进行了8494例次髋关节或膝关节置换，Malinzak等对其进行了回顾并将深感染者和未感染者进行对照研究。结果发现43例深部感染（30例与全膝关节置换有关，13例与全髋关节置换有关），发病率为0.51%。肥胖、年龄较轻及糖尿病为确定的易发生感染的高危因素。病态肥胖的患者（体重指数【BMI】＞50kg/m2）发生感染的几率明显增加（概率21.3）。行全膝关节置换小组中，40kg/m2＜BMI＜50kg/m2的患者发生感染的几率较BMI＜40kg/m2的患者高约3.3倍。膝关节感染患者的平均年龄为62.8岁，膝关节未感染患者的平均年龄为69.2岁。糖尿病患者发生深部感染的可能性要比非糖尿病患者高出3.1倍。其他的研究证明，对糖尿病患者在围手术期进行严格的血糖控制有益于临床康复。Marchant等对血糖控制较好和较差的患者进行了对比，发现全膝关节置换术后，后者发生伤口感染的几率较前者增加（概率2.28）。Bolognesi等对全国住院患者进行抽样并对其中751,340例初次手术和翻修患者的住院记录进行回顾，其中64,239例为糖尿病患者，结果发现糖尿病患者的感染率并未增加。但是，这一结果可能与NIS没有设计收集初次住院的并发症的数据有关，可能不包括大多数关节假体周围感染。

Obesityisalsoahostriskfactorforinfectionassociatedwithwound-healingcomplications.Wparedagroupofmorbidlyobesepatientswhohadhadatotaloffiftytotalkneearthroplastieswithacontrolgroupofnon-morbidlyobesepatientswhohadhadatotalof1768totalkneearthroplasties23.Inthemorbidlyobesegroup,therewasa22%rateofwoundcomplications(elevenpatients)andfivedeepinfections.Incontrast,thecontrolgrouphada2%rateofwoundcomplicationsanda0.6%rateofdeepinfections.Thenutritionalstatusofobesepatientsshouldbeevaluatedbyobtainingserumalbuminandtransferrinlevelsaswellasatotallymphocytecount.Iftheirnutritionalstatusispoor(atransferrinlevelof<200mg/dL,analbuminlevelof<3.5g/dL,oratotallymphocytecountof<1500cells/mm3),obesepatientsshouldbereferredtoaprimarycareproviderornutritionistpriortototalkneearthroplasty.

肥胖也是感染的主要危险因素，与伤口愈合并发症相关。Winiarsky等对病态性肥胖、共50例全膝关节置换的患者和非病态性肥胖、共1768例全膝关节置换的患者进行了比较，病态肥胖组伤口感染发生率约为22%（11/50），5例发生深部感染。对照组中伤口感染的发生率为2%，深部感染的发生率为0.6%。通过检测血清蛋白、转铁蛋白水平及总淋巴细胞计数对肥胖患者的营养状态进行评估，如果营养状态较差（转铁蛋白＜200mg/dL，血清蛋白<3.5g/dL或淋巴细胞计数<1500个/mm3)，全膝关节置换术前应当先行基础营养支持治疗。

Patientsatincreasedriskforinfectionbecauseofobesityshouldbeinformedofthatriskandcounseledaboutwaystoreduceit.Ifamorbidlyobesepatienthasanadequatenutritionalstatus,bariatricsurgerymayberecommendedpriortoarthroplasty.

对于因肥胖而感染风险增加的患者，应当告知其风险并推荐降低风险的一些方法。如果病态肥胖患者营养状态较好，建议在行全膝关节置换术前行减肥手术。

Postoperativewounddrainageandwound-healingcomplicationsareassociatedwithanincreasedprevalenceofinfections.Astudycomparingseventy-eightpatientswhohadaperiprostheticjointinfectionwithacontrolpopulationwithoutaninfectionshowedthathematomaformation,wounddrainage,andameaninternationalnormalizedratio(INR)of>1.5hadbeenmoreprevalentinthegroupwithaperiprostheticjointinfection24.Galatetal.reviewedthecasesofforty-twopatients(forty-twoknees)whohadhadsurgicalevacuationofapostoperativehematomawithinthirtydaysafteraprimarytotalkneearthroplasty25.Anadditionalgroupofforty-twopatientswasmatchedtothegroupinanattempttoidentifyriskfactorsforthedevelopmentofthehematoma.Thetwo-yearprobabilitiesofadditionalmajorsurgery(componentresection,muscleflapcoverage,oramputation)andofdevelopingadeepinfectionwere12.3%and10.5%,respectively,inthepatientswhohadsurgicalevacuationofthehematoma.Inthecontrolgroup,theprobabilitiesforthesamecomplicationswere0.6%and0.8%.Ahistoryofableedingdisorderhadasignificantassociationwiththedevelopmentofahematomarequiringsurgicalevacuation(p=0.046).Mataretal.reportedseveraladditionalpreoperative,intraoperative,andpostoperativefactorsthatareassociatedwithperiprostheticjointinfection.Theseauthorsproviderecommendationsforaddressingfactorsthatmaycontributetoorincreasetheriskofinfection26.

术后伤口引流及伤口愈合过程中的并发症与感染的发生率增加有关。一项对78例发生关节假体周围感染的患者和没有感染的对照组患者的对比研究显示，血肿形成、伤口引流、平均INR＞1.5在关节假体周围感染组中较为常见。Galat等对初次全膝关节置换术后30天内发生血肿并行血肿清除术的42例患者进行了回顾，另外42例患者为对照组，目的是确定发生血肿的解除因素。血肿清除患者中术后2年需要再行手术和发生深部感染的概率分别是12.3%、10.5%，对照组中，同样的并发症的概率分别是0.6%和0.8%。有出血性疾病病史与术后发生血肿且需要手术清除明显相关(p=0.046)。Matar等报道了术前、术中、术后与关节假体周围感染相关的一些其它因素，这些学者建议要对可能导致或增加感染的危险因素进行处理。

Diagnosis

诊断

Theevaluationofpatientssuspectedofhavingaperiprostheticjointinfectionshouldfollowalogicalsequence.TheAAOSdevelopeda‘‘ClinicalPracticeGuideline’’tohelpstandardizethisprocess(Figs.1,2,and3).Thepatient’shistoryandphysicalexaminationshouldinitiallyraisesuspicionthatthereisaninfection.Typically,patientswithaperiprostheticjointinfectiondescribealmostcontinuouspainandusuallyhavestiffnessorlimitedkneemotion.Feverormalaiseisstronglysuggestiveofinfection,buttheyarenottypicalfindings.Ifadrainingsinusispresent,thejointisconsideredtobeinfecteduntilprovenotherwise.

对可疑关节假体周围感染的患者的评估应遵循逻辑，AAOS提出了“临床实践指南”以使评估程序更标准化（图1,2,3）。根据患者的病史及体格检查，应当首先对是否感染提出疑问。尤其是关节假体周围感染的患者多数表现为膝关节持续性的疼痛，通常伴有关节僵硬或活动受限。发热或全身不适强烈提示感染，但并不典型。如果出现静脉塌陷，只有在其他方面得到确认，才能考虑为关节感染。

Thenextstepintheevaluationofpatientsforwhomthereisaclinicalsuspicionofinfectionistheuseoflaboratorytests27.Theerythrocytesedimentationrate(ESR)andC-reactiveprotein(CRP)levelshouldbemeasuredwheneverapatientissuspectedofhavinganinfectionatthesiteofatotaljointarthroplasty.Thecutofffornormalandabnormalvaluesfortheseinflammatorymarkerswasevaluatedprospectivelyinastudyof151kneesin145patientswhohadpresentedforrevisionkneesurgery27.ThisstudysuggestthatanESRof>22.5mm/hr(normal,30mm/hr)andaCRPlevelof>13.5mg/L(normal,10mg/L)werereliablysuggestiveofaperiprostheticjointinfection.

评估可疑感染的另外一个方法是实验室检查，对可疑全膝关节置换手术部位有感染的患者，均应当检测血沉（ESR）及C-反应蛋白（CRP）水平。在一项对145例曾行膝关节翻修术的患者共151例次膝关节的术前研究中，对炎性标志正常和异常价值标准进行评估。该研究指出对于ESR>22.5mm/hr，CRP>13.5mg/L者，则明确提示关节假体周围存在感染。

Thediagnosticaccuracyoftheinterleukin-6(IL-6)serumlevelwasevaluatedinaprospectivestudyoffifty-eightpatientswithaperiprostheticjointinfection28.IL-6isproducedbystimulatedmacrophages,butthelevelreturnstonormalforty-eighttoseventy-twohoursafteraprocedure.TheauthorsfoundthattheIL-6levelwasamoreaccuratemarkerthaneithertheESRortheCRPlevelforthedetectionofperiprostheticinfection.Ameta-analysisofpublicationsrelatedtothediagnosisofinfectionsaroundprostheticjointsincludedthirtyeligiblestudieswithdataonatotalof3909hipandkneearthroplasties29.Theprevalenceofperiprostheticjointinfectionwas32.5%.ThebestdiagnosticaccuracywasprovidedbytheIL-6level,followedbytheCRPlevel,ESR,andwhiteblood-cell(WBC)count.Oneoftheweaknessesofthatmeta-analysiswasthatitincludedonlyonelargestudyandtwosmallerstudiesmeasuringtheusefulnessoftheIL-6levelbuttwenty-fivestudiesevaluatingtheusefulnessoftheESR,twenty-threeevaluatingtheusefulnessoftheCRPlevel,andfifteenevaluatingtheusefulnessoftheWBCcount.Thecostofeachofthesetestswasnotevaluated.

在一项58例关节假体周围感染患者的前瞻性研究中，作者对血清IL-6水平的诊断准确性进行了评估。IL-6由受刺激的巨噬细胞产生，但是术后48-72小时的水平值是正常的。作者认为，在发现假体周围感染方面，IL-6水平值是一个比ESR或CRP更为精确的指标。对诊断为关节假体周围感染有关的文献进行荟萃分析，其中包括30项符合条件的研究，共有3909例次的髋关节和膝关节进行了置换。关节假体周围感染的发生率为32.5%，最准确的诊断条件是IL-6水平，接下来依次是CRP水平、ESR和WBC。荟萃分析的缺点之一是仅有一项大样本和两项小样本研究是针对IL-6水平的作用，25项研究是评估ESR的作用，23项研究是评估CRP的作用，15项研究是评估WBC的作用。这些检测的成本均未进行评估。

Thenextstepwhensuspicionofinfectionpersistsisaspirationatthesiteoftheprostheticjointandanalysisoftheperiprostheticfluid.Theanalysisoftheaspiratedfluidshouldincludeacellcounttodeterminetheabsolutenumberofleukocytesandthepercentageofcellsthatareneutrophils.Somewherebetween1100and3000leukocytes/mLindicatesaninfection30,31.Thepercentageofleukocytesthatareneutrophilsshouldbeatleast60%forthejointtobeconsideredinfected32-34.Finally,specimensofthefluidshouldbeculturedtoidentifybacteriaandtheirsensitivitytoavailableantibiotics.Gramstainingoffluidspecimenshasapoorsensitivityandapoorpredictivevalue,andtheresultsdonotgenerallyalterthepatient’streatment35.

当怀疑存在感染时，另一个方法是对关节假体周围进行穿刺抽液并对假体周围的液体进行分析。对穿刺液进行分析应当包括细胞计数，以确定白细胞的绝对数和中性粒细胞所占百分比。如果某一部位的白细胞计数在1100-3000个/mL之间，则表示有感染。中性粒细胞所占白细胞的百分比至少为60%，则考虑关节感染。最后，应当对穿刺液样本进行培养，以确定细菌类型及对抗生素的敏感性。对穿刺液样本进行革兰氏染色敏感性较差，预测价值不高，结果通常不会改变患者的治疗方案。

Intheearlypostoperativeperiod,levelsofinflammatorymarkersandthesynovialWBCcountmaybeelevateddespitethejointnotbeinginfected.Bedairetal.evaluatedtheresultsofkneeaspirationsperformedwithinsixweeksafterprimarytotalkneearthroplastiesandcomparedtheESR,CRPlevel,andWBCcountanddifferentialbetweenpatientswithandthosewithoutapostoperativeinfection36.TheCRPlevel,synovialWBCcount,andpercentageofpolymorphonuclearcellsinthedifferentialWBCcountwerefoundtobehigherintheinfectedgroup,buttheoptimalcutoffforthesynovialWBCcountasareliablemarkerofinfectionwasmuchhigherthanthenumbersgivenabove.ThisstudyshowedasynovialWBCcountof27,800cells/mLintheaspiratefromthesiteofatotalkneearthroplastyintheacutepostoperativeperiodtobethebestpredictorofinfection.Withtheuseofthiscutoff,therewasa94%positivepredictivevalueanda98%negativepredictivevalue.

在术后早期，尽管关节没有感染，但炎性标志水平及滑液中的WBC计数也可能会升高。Bedair等在初次全膝关节置换术后6周对膝关节进行穿刺结果进行分析评估，并对术后感染和未感染患者的ESR、CRP及WBC计数及其差异进行了比较。CRP水平、滑液中WBC计数及多形核细胞在不同白细胞计数中所占百分比在感染组中较高，但是滑液中WBC计数最佳值作为感染的可靠指标比上述所给数值的可靠性均较高。本研究表明，全膝关节置换部位穿刺滑液中WBC计数27,800个/mL，则是术后急性感染的最佳预测指标。利用这一数值，其阳性预测率为94%，阴性预测率为98%。

Aerobic,anaerobic,andfungalculturesareperformedroutinely,whereasmoleculartestinghasthepotentialforroutineusebutcurrentlyisdevelopmental.Thechallengesfacingorthopaedicsurgeonsincludebothfalse-positiveandfalse-negativecultures.False-positivefluidandtissueculturesareunfortunatelycommon37.Ifthehistory,physicalfindings,levelsofinflammatorymarkers,andcellcountinthefluidarenormal,thenitishighlyprobablethatapositivecultureisfalse-positive.Thecorollarytothisdilemmaiswhenthehistory,physicalfindings,levelsofinflammatorymarkers,andcellcountinthefluidareelevatedbutthecultureisnegative.Thisproblemoffalse-negativeculturesisalsocommon;itmayoccur5%to10%ofthetime38.Berbarietal.studied897casesofperiprostheticjointinfectionseenoveraten-yearinterval.Sixty(7%)oftheinfectionswereassociatedwithnegativecultures,andinthirty-two(53%)ofthesesixtycasesthepatienthadreceivedpriorantibiotics.Ofthesixtyinfections,thirty-four(57%)weretreatedwithatwo-stageimplantexchange;twelve(20%),withdebridementandcomponentretention;eight(13%),withresectionarthroplasty;five(8%),withone-stageexchange;andone(2%),withamputation.Patientsweretreatedwithparenteralantibioticsforanaverageoftwenty-eightdays,withforty-nine(82%)ofthemreceivingacephalosporin.Thefive-yearestimateofimplantsurvivalwithoutinfectionwas94%forthepatientswithatwo-stageexchangeand71%forthosetreatedwithdebridementandcomponentretention.Thestudyhighlightstheimportanceoftreatingthesepatientslikepatientswithpositivecultures.Theprotocolofparenteralantibioticsandatwo-stageexchangecanbeexpectedtohaveahighrateofsuccessforpatientswithaperiprostheticjointinfectionwhohavenegativecultures.

常规进行需氧、厌氧和真菌培养，但是目前还在发展阶段的分子检测也可能成为常规方法。骨科医生面临的挑战包括假阳性和假阴性培养结果，而且不幸的是，假阳性液体和组织培养较为常见。如果病史、体格检查、炎性指标的水平值及穿刺液中细胞计数都正常，那么阳性培养结果很可能是假阳性的。当患者病史、体格检查结果、炎性指标水平值及穿刺液中细胞计数升高但培养结果呈阴性，那么就很难下结论。假阴性培养结果也比较常见，发生率在5%-10%之间。Berbari等对超过10年间的897例关节假体周围感染的患者进行了研究，发现60例（7%）患者培养结果为阴性，这其中有32例（53%）患者曾行抗生素治疗。60例感染患者中，34例（57%）二期更换内植物，12例（20%）进行清创并部分保留内植物，8例（13%）行人工关节取出术，5例（8%）进行一期重新置换，1例（2%）行截肢术。患者静脉注射抗生素治疗平均28天，49例（82%）使用头孢菌素治疗。一期置换而无感染者的5年生存率为94%，而进行清创、保留组件患者5年生存率为71%。本研究突出强调了对细菌培养为阳性患者进行治疗的重要性。对关节假体周围感染而细菌培养呈阴性的患者而言，经肠外给予抗生素和二期更换内植物的治疗方案成功率较高。

Management

Segawaetal.suggestedaclinicallyusefulclassificationofdeepperiprostheticinfections39.Type-Iinfectionsarethoseidentifiedfromroutineculturesofspecimensobtainedatthetimeofanarthroplastyrevisionwhenaninfectionwasnotexpected.Thesurgicalrevisionusedtotreatthistypeofinfectionincludesappropriatedebridementandcomponentexchangeandthereforeiscomparablewithaone-stagereimplantation.Thetreatmentiscompletedbyadministeringparenteralantibioticsforfourtosixweeks.Oralantibiotictherapymaybeusedafterthecompletionofparenteralantibiotictherapy.

Segawa等建议对深部假体周围感染进行临床分类，I型感染是指此前没有发现感染，但在翻修时对标本进行常规培养确定有感染者。翻修手术用于治疗此类感染，包括适当的清创、更换部分装置，因此与一期重新植入内固定相当，完整治疗需要静脉应用抗生素4-6周。静脉应用抗生素治疗后予以口服抗生素治疗是有帮助的。

Type-IIinfectionsareearlypostoperativeinfections—i.e.,thosediscoveredwithinthefirstmonthaftersurgery.AType-IIinfectionshouldbetreatedwithsurgicaldebridementandcomponentretentionfollowedbyafourtosix-weekcourseofparenteralantibioticsandpossiblyoralantibioticsforadefinedinterval.Ifthesurgeonhasassumedthecareofapatientwhohadsurgicalrevisionelsewhereandnotesthatthecultureofspecimensobtainedduringthesurgicalprocedureispositive,thenitmaybenecessarytorepeatthedebridement.Severalfactorsshouldbeconsidered,includingthetypeofbacteriaandantibioticsensitivity,thecomplexityofananticipatedresectionandreimplantationatalaterdate,andthegeneralhealthandimmunestatusofthepatient.

II型感染是指术后早期感染，即在术后1个月内出现的感染。II型感染的治疗包括：手术清创、保留假体，静脉应用抗生素4-6周及可能口服抗生素一定时间。如果外科医师已经对在外院行翻修手术的患者采取治疗，并指出术中标本细菌培养为阳性，可能仍需要再次进行清创。应考虑以下几种因素：细菌种类、抗生素敏感性、将来预期切除和重新植入假体的复杂性、患者全身状况和免疫状态。

Type-IIIinfectionsoccuryearsafterimplantationandareacutehematogenousinfectionsfromaremotesourcethatisnormallyknown.Ifthesymptomsofinfectionhavebeenpresentfortwotothreeweeksorless,theimplantiswellfixed,andthepatientisimmunocompetent,thensurgicaldebridement,componentretention,andparenteralantibioticsmaysalvagethearthroplasty.Salvagehasasuccessraterangingfrom30%toashighas90%40-42.Azzametal.recentlystudiedthesuccessofirrigationanddebridementwithcomponentretentionfortreatmentofType-IIandType-IIIinfectionsaroundprostheticjointsin104patientstreatedatasingleinstitutionandfollowedforanaverageof5.7years43.Withcomponentresectionormicrobiologicallyproveninfectionastheendpoint,thesuccessratewas44%.Theauthorsnotedthatpatientswithstaphylococcalinfection,higherASA(AmericanSocietyofAnesthesiologists)scores,andpurulencearoundtheprosthesishad