ASTM_F_1800_-_12.pdf

Designation:F180012Standard Practice forCyclic Fatigue Testing of Metal Tibial Tray Components ofTotal Knee Joint Replacements1This standard is issued under the fixed designation F1800;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 covers a procedure for the fatigue testingof metallic tibial trays used in knee joint replacements.Thispractice covers the procedures for the performance of fatiguetests on metallic tibial components using a cyclic,constant-amplitude force.It applies to tibial trays which cover both themedial and lateral plateaus of the tibia.This practice mayrequire modifications to accommodate other tibial tray designs.1.2 This practice is intended to provide useful,consistent,and reproducible information about the fatigue performance ofmetallic tibial trays with one unsupported condyle.1.3 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.4 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2E4 Practices for Force Verification of Testing MachinesE467 Practice for Verification of Constant Amplitude Dy-namic Forces in an Axial Fatigue Testing SystemE468 Practice for Presentation of Constant Amplitude Fa-tigue Test Results for Metallic MaterialsE1150 Definitions of Terms Relating to Fatigue(Withdrawn1996)33.Terminology3.1 Definitions:3.1.1 R valueThe R value is the ratio of the minimum loadto the maximum load.R 5minimum loadmaximum load(1)3.2 Definitions of Terms Specific to This Standard:3.2.1 anteroposterior centerlinea line that passes throughthe center of the tibial tray,parallel to the sagittal plane andperpendicular to the line of load application.For asymmetrictibial tray designs,the appropriate center of the tibial tray shallbe determined by the investigator and the rationale reported.3.2.2 fixture centerlinea line that passes through the centerof the fixture,parallel to the anteroposterior centerline.Thisline represents the separation between the supported andunsupported portions of the test fixture.3.2.3 mediolateral centerlinea line that passes through thecenter of the tibial tray,parallel to the coronal,or frontal,planeand perpendicular to the line of load application.For asym-metric tibial tray designs,the appropriate center of the tibialtray shall be determined by the investigator and the rationalereported.3.2.4 moment arm,dapthe perpendicular distance betweenthe mediolateral centerline of the tibia component and the lineof load application.3.2.5 moment arm,dmlthe perpendicular distance betweenthe anteroposterior centerline of the tibia component and theline of load application.4.Significance and Use4.1 This practice can be used to describe the effects ofmaterials,manufacturing,and design variables on the fatigueperformance of metallic tibial trays subject to cyclic loadingfor relatively large numbers of cycles.4.2 The loading of tibial tray designs in vivo will,in general,differ from the loading defined in this practice.The resultsobtained here cannot be used to directly predict in vivoperformance.However,this practice is designed to allow forcomparisons between the fatigue performance of differentmetallic tibial tray designs,when tested under similar condi-tions.1This 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 Dec.15,2012.Published January 2013.Originallyapproved in 1997.Last previous edition approved in 2007 as F1800 07.DOI:10.1520/F1800-12.2For 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.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 4.3 In order for fatigue data on tibial trays to be comparable,reproducible,and capable of being correlated amonglaboratories,it is essential that uniform procedures be estab-lished.5.Specimen Selection5.1 The test component selected shall have the same geom-etry as the final product,and shall be in finished condition.6.Apparatus6.1 The tibial tray shall be mounted as a cantilever beam(see Fig.1 and Fig.2).Care shall be taken to ensure that thefixation of the tibial tray doe