1、Designation: F2580 09F2580 13Standard Test Method Practice forEvaluation of Modular Connection of Proximally FixedFemoral Hip Prosthesis1This standard is issued under the fixed designation F2580; the number immediately following the designation indicates the year oforiginal adoption or, in the case
2、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 covers a procedure for the fatigue testing of metallic femoral hip prosthese
3、s used in hip joint replacements.This test method covers the procedures for the performance of fatigue tests on metallic femoral hip stems using a cyclic,constant-amplitude force. It applies to hip prostheses that utilize proximal metaphyseal fixation and are of a modular construct, andit is intende
4、d to evaluate the fatigue performance of the modular connections in the metaphyseal filling (that is, proximal body)region of the stem.1.2 This test method is intended to provide useful, consistent, and reproducible information about the fatigue performance ofmetallic hip prostheses while held in a
5、proximally fixated manner, with the distal end not held by a potting medium.1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.4 This standard does not purport to address all of the safety concerns, if any, associated with
6、its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E467 Practice for Verification of Constant Amplitude Dynamic Forces in a
7、n Axial Fatigue Testing SystemE468 Practice for Presentation of Constant Amplitude Fatigue Test Results for Metallic MaterialsE1150 Definitions of Terms Relating to Fatigue (Withdrawn 1996)32.2 ISO Standards:4ISO 72064 Determination of Endurance Properties of Stemmed Femoral Components with Applicat
8、ion of Torsion3. Terminology3.1 Definitions:3.1.1 R value, nThe R value is the ratio of the minimum load to the maximum load.R 5 minimum loadmaximum load3.2 Definitions of Terms Specific to This Standard:3.2.1 extractionremoval of the femoral hip implant from the femur during surgery.3.2.2 extractor
9、 holea hole in the proximal body of the stem in which an apparatus is placed to remove the implant from thefemur.3.2.3 femoral headconvex spherical bearing member for articulation with the natural acetabulum or prosthetic acetabulum.3.2.4 femoral head offsetthe perpendicular distance from the center
10、line of the implant stem to the center of the femoral head.1 This test method practice is under the jurisdiction of ASTM Committee F04 on Medical and Surgical Materials and Devices and is the direct responsibility ofSubcommittee F04.22 on Arthroplasty.Current edition approved Sept. 15, 2009Feb. 1, 2
11、013. Published September 2009February 2013. Originally approved in 2007. Last previous edition approved in 20072009as F2580 07.F2580 09. DOI: 10.1520/F2580-09.10.1520/F2580-13.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For
12、 Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 The last approved version of this historical standard is referenced on www.astm.org.4 Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York,
13、 NY 10036, http:/www.ansi.org.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommend
14、s that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.2.5 frontal plan
15、ethe plane that lies in the medial-lateral direction of the implant. Adduction occurs in this plane.3.2.6 implant centerlinethe axis that runs vertically from the proximal body of the implant, down the center of the stem tothe distal end.3.2.7 pivot axisthe center of rotation of the pivot fixture (a
16、nd prosthesis potted within it) within the test fixture setup; itslocation is determined by the intersection of the neck and stem centerlines of the prothesis (Figs. 1 and 2).3.2.8 pivot fixturethe fixture in which the specimen is potted, and is attached to the main test fixture; characterized by tw
17、o pinson the side that serve as the pivot axis.3.2.9 rotational planethe plane that lies perpendicular to the stem axis of the implant.3.2.10 sagittal planethe plane that lies perpendicular to the Frontal plane; flexion occurs in this plane.4. Significance and Use4.1 This test method can be used to
18、describe the effects of materials, manufacturing, and design variables on the fatigueperformance of metallic femoral hip prostheses subject to cyclic loading for large numbers of cycles.4.2 The loading of femoral hip designs in vivo will, in general, differ from the loading defined in this test meth
19、od. The resultsobtained here cannot be used to directly predict in vivo performance. However, this test method is designed to allow forcomparisons between the fatigue performance of different metallic femoral hip designs, when tested under similar conditions.4.3 In order for fatigue data on femoral
20、hip prostheses to be comparable, reproducible, and capable of being correlated amonglaboratories, it is essential that uniform procedures be established.5. Specimen Selection5.1 The test component selected shall have the same geometry as the final product, and shall be in finished condition. The tes
21、tcomponent shall be of the worst-case size and configuration (that is, the component that produces the highest stresses) of theimplant family to be tested.5.2 The femoral head component selected for load application shall be of the same design and material as a current product inuse, but may be prev
22、iously tested.5.3 The femoral head selected shall offer the greatest load offset from the hip centerline, to represent a worst-case bendingscenario during testing.6. Apparatus6.1 The hip implant may be tested in different orientations to better reproduce specific testing conditions that are beingeva
23、luated. For example:An anatomical orientation of 9 flexion, and 10 adduction (per ISO 7206-4), or vertically in both planes.The criteria used to determine the orientation should be reported.6.2 Care shall be taken to ensure that the fixation of the implant does not produce abnormal stress concentrat
24、ions that couldchange the failure mode of the part.FIG. 1 Free Body Diagram of Test SetupF2580 1326.3 A fixed-bearing load applicator shall be used to keep the specimen aligned in the chosen orientation during testing, as wellas a fixture that allows the stem to bend during testing, such as a u-join
25、t.6.4 The fixture used to hold the implant during testing should have a reaction bolt that will oppose the loading on the femoralhead, keeping the implant in equilibrium. The position of the reaction bolt should be adjustable to accommodate stems of differentlengths and design features.6.5 The fixtu
26、res and aligning materials used should be of a design that positions the implant, when potted, so that: the pointdefined by the intersection of the neck and stem centerlines is coincident with the pivot axis (Fig. 1), the stem is fixed verticallyin both medial/lateral and anterior/posterior directio
27、ns, the stem is aligned facing forward in the rotational plane (that is, the frontalplane is normal to the pivot axis of the fixture), (Fig. 3) and that any mating surfaces between modular components of the specimendo not come in contact with the potting medium.7. Equipment Characteristics7.1 Perfor
28、m the tests on a fatigue test machine with adequate load capacity.7.2 Analyze the action of the machine to ensure that the desired form and periodic force amplitude is maintained for the durationof the test (see Practice E467 or use a validated strain-gauged part).7.3 The test machine shall have a l
29、oad monitoring system such as a transducer mounted in line with the specimen. Monitor thetest loads continuously in the early stages of the test and periodically thereafter to ensure the desired load cycle is maintained.Maintain the varying load as determined by suitable dynamic verification at all
30、times to within 62 % of the largest compressiveforce being used.FIG. 2 Schematic Representation of the Test Set-upF2580 1338. Procedure8.1 This procedure details a potting method centered about potting the proximal body portion of the implant first, andassembling the remainder of the implant after p
31、otting. Other methods of potting the specimen exist, including methods for implantsthat are not of a modular design, and may be used in place of this, providing that the general terms and limitations are still achieved.The potting procedure used should be included in the test report.8.2 Specimen Pre
32、paration:8.2.1 Apply a moderate coat of lubricant (that is, any household cooking spray) to the interior of the pivot fixture and any otherfixture surfaces that will contact the potting medium to prevent adhesion during potting.8.2.2 Align the proximal body component of the implant in the pivot fixt
33、ure, using the aligning materials to ensure it is in thecorrect orientation. Be sure the component and fixtures are fitted tightly so the specimen does not move during potting and curing.The distal potting level shall be at the distal surface of the proximal body component (see Figs. 1 and 2).8.2.3
34、An appropriate potting medium should be chosen which displays the correct load carrying capabilities and resistance tocracking or crumbling during fatigue. Examples of different potting media include bone cement, dental acrylic, or a low meltingpoint alloy. The type and manufacturer of the potting m
35、aterial chosen should be reported.8.2.4 Pour the potting material into the pivot fixture, around the specimen. If necessary, use another material such as tape orclay to block any gaps to prevent the material from seeping through to any area outside the pivot fixture. Care should be takento ensure th
36、at potting medium does not come in contact with any mating surfaces on the proximal component.8.2.5 The proximal potting level shall be at the proximal surface of the proximal body component (see Figs. 1 and 2). No pottingmaterial should enter any space between modular components of the specimen.8.2
37、.6 Allow the material to cure completely before continuing.8.3 Specimen Assembly and Impaction:8.3.1 Remove all secondary fixtures used to align the implant in the pivot fixture.8.3.2 Clean the internal and distal surfaces of the proximal component with acetone to remove any potting or other materia
38、l thatcame into contact with the surface. Avoid allowing the acetone to contact the good potting material.8.3.3 Assemble the remainder of the implant, ensuring that the stem remains aligned properly in all planes of interest.8.3.4 Assemble the modular components of the stem body as specified by the
39、surgical technique for the device.8.3.5 Place the femoral head on the neck taper of the hip implant and impact the head on the taper with three blows with a rubbermallet.8.3.6 Determine the femoral head offset from the centerline of the stem. This can be done by means of a height gauge or opticalcom
40、parator.8.4 Test Set-up:8.4.1 Attach the pivot fixture with the specimen to the test frame fixture in the correct orientation.8.4.2 Attach the polyethylene load applicator to the actuator.8.4.3 Bring the load applicator into contact with the femoral head of the specimen so that a low load (approxima
41、tely 10 lbf)is applied.8.4.4 Vertically position the reaction bolt assembly so that it is located 66 mm from the pivot axis (Fig. 2). If the stem designincludes a coronal slot, the reaction bolt should be located above the highest level of the coronal slot.NOTE 1Once assembled, the pivot axis will b
42、e coincident with the point on the implant defined by the intersection of the neck and stem centerlines.FIG. 3 Proximal Sleeve Component Potted in Pivot FixtureF2580 134NOTE 1The vertical position of the reaction bolt may be modified to accommodate designs and test purposes different from what is ex
43、plained in thistest method.8.4.5 Adjust the main fixture and the pivot fixture so that the specimen is aligned at the proper angles in the frontal plane(adduction) and in the sagittal plane (flexion) (See 6.1). The test setup is represented in Fig. 2.8.4.6 Proper measures should be taken to ensure t
44、hat the fixturing is secure and the specimen or equipment does not getdamaged should unloading occur during testing8.4.7 Test FrequencyRun all tests at a frequency of 10 Hz or less. constant frequency with a maximum allowable frequencyof 10 Hz. Take care to ensure that the test machine can maintain
45、the applied load at the chosen frequency and that resonantconditions are not reached.8.4.8 Input Loading ProfileRun all tests using a sinusoidal waveform input load with an R value of 10.0NOTE 2In strict terms, since the force applied to the femoral head is compressive, the maximum force is the smal
46、lest negative amplitude.Consequently, the R value is ten when the negative signs cancel each other. In terms of applied bending moment at the potting plane, the R value wouldbe 0.1. See Terminology E1150 for the definition of the R value.9. Test Termination9.1 Continue the test until the femoral pro
47、sthesis fails or until a predetermined number of cycles have been applied to theimplant. The suggested number of cycles is ten million. Failure may be defined as: a fracture of the femoral implant; formationof a crack detectable by eye, fluorescent dye penetrant, or other non-destructive means; or e
48、xceeding a predetermined deflectionlimit.10. Report10.1 Report the fatigue test specimens, procedures, and results in accordance with Practice E468.10.2 In addition, report the following parameters:10.2.1 Femoral implant (size, configuration, material, and so forth),10.2.2 Femoral head size and offs
49、et,10.2.3 Femoral head offset measured from stem center,10.2.4 Method of assembly of the modular components,10.2.5 Stem orientation and the criteria used to determine it (per 6.1),10.2.6 Distance to reaction bolt from distal potting plane,10.2.7 Potting procedure,10.2.8 Potting medium,10.2.9 Largest compressive load,10.2.10 R value,10.2.11 Cycles to failure,10.2.12 Mode and location of failures,10.2.13 Test environment, and10.2.14 Test frequency.11. Precision and Bias11.1 The precision and bias of this test method is being established. The test results th
