ASTM_F_2025_-_06_2012.pdf

Designation:F202506(Reapproved 2012)Standard Practice forGravimetric Measurement of Polymeric Components forWear Assessment1This standard is issued under the fixed designation F2025;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This practice describes a laboratory method using aweight-loss(that is,mass-loss;see X1.4)technique for evalu-ating the wear properties of polymeric materials or deviceswhich are being considered for use as bearing surfaces ofhuman joint replacement prostheses.The test specimens areevaluated in a device intended to simulate the tribologicalconditions encountered in the human joint;for example,use ofa fluid such as bovine serum,or equivalent pseudosynovialfluid shown to simulate similar wear mechanisms and debrisgeneration found in vivo.2.Referenced Documents2.1 ASTM Standards:2D792 Test Methods for Density and Specific Gravity(Rela-tive Density)of Plastics by DisplacementD1505 Test Method for Density of Plastics by the Density-Gradient TechniqueF732 Test Method for Wear Testing of Polymeric MaterialsUsed in Total Joint ProsthesesF1714 Guide for Gravimetric WearAssessment of ProstheticHip Designs in Simulator Devices2.2 Other Standards:3ISO 142422 Implants for SurgeryWear of Total Hip-JointProsthesesPart 2:Methods of MeasurementISO 142432 Implants for SurgeryWear of Total Knee-Joint ProsthesesPart 2:Methods of Measurement3.Significance and Use3.1 This practice uses a weight-loss method of wear deter-mination for the polymeric components or materials used inhuman joint prostheses,using serum or demonstrated equiva-lent fluid for lubrication,and running under a load profilerepresentative of the appropriate human joint application(1,2).4The basis for this weight-loss method for wear mea-surement was originally developed(3)for pin-on-disk wearstudies(Practice F732)and has been extended to total hipreplacements(4,5,ISO 142422,and Guide F1714),and tofemoro-tibial knee prostheses(6 and ISO 142432),and tofemoro-patellar knee prostheses(6,7).3.2 While wear results in a change in the physical dimen-sions of the specimen,it is distinct from dimensional changesdue to creep or plastic deformation,in that wear results in theremoval of material in the form of polymeric debris particles,causing a loss in weight of the specimen.3.3 This practice for measuring wear of the polymericcomponent is suitable for various simulator devices.Thesetechniques can be used with metal,ceramic,carbon,polymeric,and composite counter faces bearing against a polymericmaterial(for example,polyethylene,polyacetal,and so forth).Thus,this weight-loss method has universal application forwear studies of human joint replacements which featurepolymeric bearings.This weight-loss method has not beenvalidated for non-polymeric material bearing systems,such asmetal-metal,carbon-carbon,or ceramic-ceramic.Progressivewear of such rigid bearing combinations has generally beenmonitored using linear,variable-displacement transducers,orby other profilometric techniques.4.Components and Materials4.1 Hip Prosthesis ComponentsThe hip joint prosthesiscomprises a ball-and-socket configuration in which materialssuch as polymers,composites,metal alloys,ceramics,andcarbon have been used in various combinations and designs.4.1.1 Component ConfigurationsThe diameter of theprosthetic ball may vary from 22 to 54 mm or larger.Thedesign may include ball-socket,trunnion,bipolar,or otherconfigurations.If applicable,the normal metal backing for thepolymeric component shall be used provided disassembly andreassembly of these components for the measurement does not1This practice is under the jurisdiction ofASTM Committee F04 on Medical andSurgical Materials and Devices and is the direct responsibility of SubcommitteeF04.22 on Arthroplasty.Current edition approved Aug.15,2012.Published September 2012.Originallyapproved in 2000.Last previous edition approved in 2006 as F2025 06.DOI:10.1520/F2025-06R12.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036.4The boldface numbers in parentheses refer to the list of references at the end ofthis standard.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 have an unrepresentative effect on the weight measurements orwear behavior.Otherwise,a modified backing may be used,again provided this has no unrepresentative effect on theweight measurements or wear behavior(see X1.5).4.2 Knee Prosthesis ComponentsThe knee joint comprisesfemor