ASTM_F_1612_-_95_2000.pdf

Designation:F 1612 95(Reapproved 2000)Standard Practice forCyclic Fatigue Testing of Metallic Stemmed Hip ArthroplastyFemoral Components with Torsion1This standard is issued under the fixed designation F 1612;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(e)indicates an editorial change since the last revision or reapproval.1.Scope1.1 This practice covers a method for the fatigue testing ofmetallic stemmed femoral components used in hip arthroplasty.The described method is intended to be used for evaluation incomparisons of various designs and materials used forstemmed femoral components used in the arthroplasty.Thispractice covers procedures for the performance of fatigue testsusing(as a forcing function)a periodic constant amplitudeforce.1.2 This practice applies primarily to one-piece prosthesesand femoral stems with modular heads,with the head in place.Such prostheses should not have an anterior-posterior A-P bowor a medial-lateral M-L bow,and they should have a nearlystraight section on the distal 50 mm of the stem.This practicemay require modifications to accommodate other femoral stemdesigns.1.3 The values stated in SI units are to be regarded as thestandard.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:E 4 Practices for Force Verification of Testing Machines2E 466 Practice for Constant Amplitude Axial Fatigue Testsof Metallic Materials2E 467 Practice for Verification of Constant Amplitude Dy-namic Loads in an Axial Load Fatigue Testing Machine2E 468 Practice for Presentation of Constant Amplitude Fa-tigue Test Results for Metallic Materials2E 1150 Definitions of Terms Relating to Fatigue22.2ISO Document:3ISO 7206-3(1988)Stem Test3.Terminology(see Fig.1 Fig.2)3.1 Definitions of Terms Specific to This Standard:3.1.1 cantilever planea plane perpendicular to the line ofload application at the level on the stem at which the stembecomes unsupported.3.1.2 distal stem axisthe centerline in the A-P projectionand the M-L projection of the most distal 50 mm of the stem.3.1.3 estimated maximum bending momentthe maximumcompressive load times the unloaded moment arm.3.1.4 geometric centroid(cantilever plane)the point in across-sectional area of the cantilever plane whose coordinatesare the mean values of the coordinates of all of the points in thearea.3.1.5 line of load applicationthe loading axis of the testmachine.3.1.6 R valuethe ratio of the minimum force to themaximum force,R 5minimum forcemaximum force3.1.7 Reference Line L1:3.1.7.1 distal stem axisthe M-L centerline of the mostdistal 50 mm of stem in the A-P projection.3.1.8 Reference Line L2:3.1.8.1 collared devicethe plane of the distal side of thecollar in the A-P projection.3.1.8.2 collarless devicethe resection plane recommendedfor the device in the A-P projection.3.1.9 Reference Point P1the spherical center of the pros-thesis head.3.1.10 Reference Point P3:3.1.10.1 collared devicethe intersection of the principalaxis of the collar(L2)with the medial surface of the stem in theA-P projection.3.1.10.2 collarless devicethe intersection of the resection1This practice is under the jurisdiction ofASTM Committee F04 on Medical andSurgical Materials and Devicesand is the direct responsibility of SubcommitteeF04.22on Arthroplasty.Current edition approved Aug.15,1995.Published December 1995.2Annual Book of ASTM Standards,Vol 03.01.3Available from American National Standards Institute,11 W.42nd St.,13thFloor,New York,NY 10036.1Copyright ASTM,100 Barr Harbor Drive,West Conshohocken,PA 19428-2959,United States.plane(L2)with the medial surface of the stem in the A-Pprojection.3.1.11 Reference Point P4the distal tip of the stem.3.1.12 Reference Point P64 the intersection of the canti-lever plane with the medial surface of the stem in the A-Pprojection.3.1.13 stem reference anglesSince the distal stem axis isobscurred by the grouting agent after preparation of the testsample,the stem reference angles are to be used to measure therepeatability of the stem orientation.They may also be used toestimate the actual orientation of the distal stem to the line ofload application if the stem geometry is well known.3.1.13.1 X(M-L)the angle between the stem referenceline and line of load application in the M-L projection.3.1.13.2 X(A-P)the angle between the stem reference lineand line of load application in the M-L and A-P projections.3.1.14 stem reference linea line passing through Refer-ence Point P6 and the center of the prosthesis head(P1).3.1.15 supported stem lengththe vertical distance be-tween the distal tip of the stem(P4)an