ASTM_F_2009_-_00_2011.pdf

Designation:F200900(Reapproved 2011)Standard Test Method forDetermining the Axial Disassembly Force of TaperConnections of Modular Prostheses1This standard is issued under the fixed designation F2009;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 test method establishes a standard methodology fordetermining the force required,under laboratory conditions,todisassemble tapers of implants that are otherwise not intendedto release.Some examples are the femoral components of atotal or partial hip replacement or shoulder in which the headand base component are secured together by a self-lockingtaper.1.2 This test method has been developed primarily forevaluation of metal and ceramic head designs on metal tapersbut may have application to other materials and designs.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Practices for Force Verification of Testing MachinesF1636 Specification for Bores and Cones for Modular Femo-ral Heads(Withdrawn 2001)33.Summary of Test Method3.1 The axial disassembly test method provides a means tomeasure the axial locking strength of the taper connection formodular prostheses.3.2 Following assembly,an axial tensile force is applied todisassemble the taper connection and the maximum force isrecorded.4.Significance and Use4.1 This test method helps to assess the axial locking forceof a modular taper.Examples of these devices are described inSpecification F1636.Some types of devices that may utilizethis type of connection are the modular shoulder and modularhip prostheses.Additional means of evaluating the lockingmechanisms of tapers may be appropriate,depending upon thedesign of the device.4.2 This test method may not be appropriate for all implantapplications.The user is cautioned to consider the appropriate-ness of the practice in view of the materials and design beingtested and their potential application.4.3 While this test method may be used to measure the forcerequired to disengage tapers,any comparison of such data forvarious component designs must take into consideration thesize of the implant and the type of locking mechanismevaluated.5.Apparatus5.1 The cone portion of the assembly shall be constrainedby suitable fixtures that can sustain high loads.5.2 The fixtures shall be constructed so that the line of loadapplication is aligned with the axes of the male and femaletaper components within 61.5.2.1 For example,modular heads may be assembled by asolid metal 100 cone as shown in Fig.1.The cone shouldprovide line contact around the diameter of the head.5.2.2 For example,modular heads may be disassembledwith a metal cage that surrounds the head and provides evencontact around the inferior edge of the head as shown in Fig.2.5.3 The testing machine shall conform to the requirementsof Practices E4.The loads used to determine the attachmentstrength shall be within the range of the testing machine asdefined in Practices E4.5.4 The test machine should be capable of delivering acompressive and tensile force at a constant displacement rate.The test machine should have a load monitoring and recordingsystem.1This test method is under the jurisdiction ofASTM Committee F04 on Medicaland Surgical Materials and Devices and is the direct responsibility of SubcommitteeF04.22 on Arthroplasty.Current edition approved March 1,2011.Published April 2011.Originallyapproved in 2000.Last previous edition approved in 2005 as F2009 00(2005).DOI:10.1520/F2009-00R11.2For 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 6.Sampling and Test Specimens6.1 The male and female taper components can be finishedimplants or they can be simplified test specimens.The testspecimens shall have tapers manufactured to the specificationsof a finished implant,including material,and preferablymanufactured with the same equipment.6.2 The supporting material around the female taper shall besimilar in size and shape to the finished implant.6.3 A minimum of five taper assemblies shall be tested todetermine the ax