Designation:F2979−14StandardGuideforCharacterizationofWearfromtheArticulatingSurfacesinRetrievedMetal-on-MetalandotherHard-on-HardHipProstheses1ThisstandardisissuedunderthefixeddesignationF2979;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thisguidespecifiesamethodtomeasurethein-vivowearofexplantedMetal-on-Metal(MoM)andother“hard”(e.g.,ceramic)hipcomponents.Theguidecoversthemeasure-mentofacetabularcupsandfemoralheadsusingadimensionalchangemethodandisapplicabletoallprosthetichiptypes,includingstemmed(modular)andresurfacinghipsystems.1.2Themethodsspecifiedinthisguidearenotapplicableformeasuringthein-vivowearfromnon-articulatingsurfaces,forexamplemodularconnections(atthestem/neck,neck/headorcupliner/shellinterface)oratacetabularcuprim.1.3Theparameters(weardepthandvolumetricwear)evaluatedandreportedinthisguideareestimatedfromtheassumedas-manufacturedshapeofthecomponents.Thewearvolumeiscalculatedusinganumericalintegrationmethodandtheweardepthisthedifferencebetweentheassumedas-manufacturedshapeandthemeasuredsurface.1.4ThisguidecoversthemeasurementofthedepthofwearandthevolumetricwearusingaCoordinateMeasuringMa-chine(CMM)andthedepthofwearusinganRoundnessMachine.Othermetrologymeasurementequipmentmaybeusedtomeasuretheweardepthorvolumeiftheresolutionandaccuracyofthemeasurementsarecomparablewiththeinstru-mentsdetailedinthisstandard.Themeasurementandanalysisprotocolsshouldbebasedonthosedescribedinthisstandard.1.5Thisguideisapplicabletohipjointswhicharenomi-nallysphericalatthetimeofmanufacture.Formdeviationsresultingfrommanufacturingordeformationmayoccurandmaynecessitatetheuseofanon-sphericalsurfacetorepresenttheunwornsurfaceofthecomponent.Hipjointsdesignedwithasymmetryareconsideredbeyondthescopeofthisguide,althoughtheprinciplesandtechniquesmaybeapplicablet...
