ThenewmillenniumandrightonschedulecomesthefourtheditionofDiagnosisofBoneandJointorders.This,then,isthethirdtimeIhaverevisedthistextsinceitsinitialpublicationin1981,morethan2decadesago.EachtimeIhavebegunworkonanewedition,Ibe-lievedincorrectlythatmyjobwouldbeeasierbecause,Ithought,howmuchinformationcouldpossiblyhavebeenintroducedinthe5or6yearsthathadelapsedsincethepreviousedition?Andeachtime,withoutex-ception,Ihavebeensurprisedbytheprogressthathasoccurredwithregardtothefurtherunderstandingandimproveddiagnosticassessmentofthemanydiseasesthataffectthemusculoskeletalsystem.Sonow,7yearsafterthepublicationofthethirdedition,thefourtheditionisofferedasclearevidencethatmuchhasbeenlearned,newconceptshaveemerged,and"oldfacts"havebeenmodifiedoreliminatedaltogether.
Iamoftenaskedatthetimeofpublicationofaneweditionpreciselyhowmuchofthematerialisappearingforthefirsttime.Thisisadifficultquestiontoanswerquantitatively.Myeducatedguessisthat30percentoftheinformationisneworhasbeenmodifiedsignificantlyfromthatcontainedinthethirdedition,thatthenumberofreferenceshasbeenexpandedby25to35percent(withemphasisgiventopertinentrecentpublications),andthatnewillustrationsrepresent25to30percentofthetotalnumberappearinginthisedition.Withregardtotheillustrativematerial,thenewfiguresunderscoretheincreasingimportanceofMRimagingasavehicleforinvestigationofthesediseases.
Thesizeofthefourtheditiondoesnotdiffersignifi-cantlyfromthatofthelastedition,althoughthenumberofvolumeshasbeendecreasedbyone.(Youwillnotethateachissomewhatheavierthaninthepast!)Tobecertainthatthismultivolumebookdidnotbecometoolarge,Iconsultedextensivelywiththefollowingchanges.