1、Designation: F 2580 07Standard Test Method forEvaluation of Modular Connection of Proximally FixedFemoral Hip Prosthesis1This standard is issued under the fixed designation F 2580; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, th
2、e 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 test method covers a procedure for the fatiguetesting of metallic femoral hip prostheses used in hip j
3、ointreplacements. This test method covers the procedures for theperformance of fatigue tests on metallic femoral hip stemsusing a cyclic, constant-amplitude force. It applies to hipprostheses that utilize proximal metaphyseal fixation and are ofa modular construct, and it is intended to evaluate the
4、 fatigueperformance of the modular connections in the metaphysealfilling (that is, proximal body) region of the stem.1.2 This test method is intended to provide useful, consis-tent, and reproducible information about the fatigue perfor-mance of metallic hip prostheses while held in a proximallyfixat
5、ed manner, with the distal end not held by a pottingmedium.1.3 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is ther
6、esponsibility 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:2E 467 Practice for Verification of Constant Amplitude Dy-namic Forces in an Axial Fatigu
7、e Testing SystemE 468 Practice for Presentation of Constant Amplitude Fa-tigue Test Results for Metallic MaterialsE 1150 Definitions of Terms Relating to Fatigue2.2 ISO Standards:3ISO 72064 Determination of Endurance Properties ofStemmed Femoral Components with Application of Tor-sion3. Terminology3
8、.1 Definitions:3.1.1 R value, nThe R value is the ratio of the minimumload to the maximum load.R 5minimum loadmaximum load3.2 Definitions of Terms Specific to This Standard:3.2.1 extractionremoval of the femoral hip implant fromthe femur during surgery.3.2.2 extractor holea hole in the proximal body
9、 of thestem in which an apparatus is placed to remove the implantfrom the femur.3.2.3 femoral headconvex spherical bearing member forarticulation with the natural acetabulum or prosthetic acetabu-lum.3.2.4 femoral head offsetthe perpendicular distance fromthe centerline of the implant stem to the ce
10、nter of the femoralhead.3.2.5 frontal planethe plane that lies in the medial-lateraldirection of the implant. Adduction occurs in this plane.3.2.6 implant centerlinethe axis that runs vertically fromthe proximal body of the implant, down the center of the stemto the distal end.3.2.7 pivot axisthe ce
11、nter of rotation of the pivot fixture(and prosthesis potted within it) within the test fixture setup; itslocation is determined by the intersection of the neck and stemcenterlines of the prothesis (Figs. 1 and 2).3.2.8 pivot fixturethe fixture in which the specimen ispotted, and is attached to the m
12、ain test fixture; characterized bytwo pins on the side that serve as the pivot axis.3.2.9 rotational planethe plane that lies perpendicular tothe stem axis of the implant.3.2.10 sagittal planethe plane that lies perpendicular tothe Frontal plane; flexion occurs in this plane.1This test method is und
13、er the jurisdiction of ASTM Committee F04 on Medicaland Surgical Materials and Devices and is the direct responsibility of SubcommitteeF04.22 on Arthroplasty.Current edition approved June 15, 2007. Published July 2007.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact AS
14、TM 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, http:/www.ansi.org.1Copyright ASTM
15、International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4. Significance and Use4.1 This test method can be used to describe the effects ofmaterials, manufacturing, and design variables on the fatigueperformance of metallic femoral hip prostheses subject toc
16、yclic loading for large numbers of cycles.4.2 The loading of femoral hip designs in vivo will, ingeneral, differ from the loading defined in this test method. Theresults obtained here cannot be used to directly predict in vivoperformance. However, this test method is designed to allowfor comparisons
17、 between the fatigue performance of differentmetallic femoral hip designs, when tested under similar con-ditions.4.3 In order for fatigue data on femoral hip prostheses to becomparable, reproducible, and capable of being correlatedamong laboratories, it is essential that uniform procedures beestabli
18、shed.5. Specimen Selection5.1 The test component selected shall have the same geom-etry as the final product, and shall be in finished condition. Thetest component shall be of the worst-case size and configura-tion (that is, the component that produces the highest stresses)of the implant family to b
19、e tested.5.2 The femoral head component selected for load applica-tion shall be of the same design and material as a currentproduct in use, but may be previously tested.5.3 The femoral head selected shall offer the greatest loadoffset from the hip centerline, to represent a worst-casebending scenari
20、o during testing.6. Apparatus6.1 The hip implant may be tested in different orientationsto better reproduce specific testing conditions that are beingevaluated. For example: An anatomical orientation of 9flexion, and 10 adduction (per ISO 7206-4), or vertically inboth planes. The criteria used to de
21、termine the orientationshould be reported.6.2 Care shall be taken to ensure that the fixation of theimplant does not produce abnormal stress concentrations thatcould change the failure mode of the part.6.3 A fixed-bearing load applicator shall be used to keep thespecimen aligned in the chosen orient
22、ation during testing, aswell as a fixture that allows the stem to bend during testing,such as a u-joint.6.4 The fixture used to hold the implant during testingshould have a reaction bolt that will oppose the loading on thefemoral head, keeping the implant in equilibrium. The positionof the reaction
23、bolt should be adjustable to accommodate stemsof different lengths and design features.6.5 The fixtures and aligning materials used should be of adesign that positions the implant, when potted, so that: thepoint defined by the intersection of the neck and stem center-lines is coincident with the piv
24、ot axis (Fig. 1), the stem is fixedvertically in both medial/lateral and anterior/posterior direc-tions, the stem is aligned facing forward in the rotational plane(that is, the frontal plane is normal to the pivot axis of thefixture), (Fig. 3) and that any mating surfaces between modularcomponents o
25、f the specimen do not come in contact with thepotting medium.FIG. 1 Free Body Diagram of Test SetupFIG. 2 Schematic Representation of the Test Set-upF25800727. Equipment Characteristics7.1 Perform the tests on a fatigue test machine with ad-equate load capacity.7.2 Analyze the action of the machine
26、to ensure that thedesired form and periodic force amplitude is maintained for theduration of the test (see Practice E 467 or use a validatedstrain-gauged part).7.3 The test machine shall have a load monitoring systemsuch as a transducer mounted in line with the specimen.Monitor the test loads contin
27、uously in the early stages of thetest and periodically thereafter to ensure the desired load cycleis maintained. Maintain the varying load as determined bysuitable dynamic verification at all times to within 62 % of thelargest compressive force being used.8. Procedure8.1 This procedure details a pot
28、ting method centered aboutpotting the proximal body portion of the implant first, andassembling the remainder of the implant after potting. Othermethods of potting the specimen exist, including methods forimplants that are not of a modular design, and may be used inplace of this, providing that the
29、general terms and limitationsare still achieved. The potting procedure used should beincluded in the test report.8.2 Specimen Preparation:8.2.1 Apply a moderate coat of lubricant (that is, anyhousehold cooking spray) to the interior of the pivot fixture andany other fixture surfaces that will contac
30、t the potting mediumto prevent adhesion during potting.8.2.2 Align the proximal body component of the implant inthe pivot fixture, using the aligning materials to ensure it is inthe correct orientation. Be sure the component and fixtures arefitted tightly so the specimen does not move during potting
31、 andcuring. The distal potting level shall be at the distal surface ofthe proximal body component (see Figs. 1 and 2).8.2.3 An appropriate potting medium should be chosenwhich displays the correct load carrying capabilities andresistance to cracking or crumbling during fatigue. Examplesof different
32、potting media include bone cement, dental acrylic,or a low melting point alloy. The type and manufacturer of thepotting material chosen should be reported.8.2.4 Pour the potting material into the pivot fixture, aroundthe specimen. If necessary, use another material such as tape orclay to block any g
33、aps to prevent the material from seepingthrough to any area outside the pivot fixture. Care should betaken to ensure that potting medium does not come in contactwith any mating surfaces on the proximal component.8.2.5 The proximal potting level shall be at the proximalsurface of the proximal body co
34、mponent (see Figs. 1 and 2).No potting material should enter any space between modularcomponents of the specimen.8.2.6 Allow the material to cure completely before continu-ing.8.3 Specimen Assembly and Impaction:8.3.1 Remove all secondary fixtures used to align theimplant in the pivot fixture.8.3.2
35、Clean the internal and distal surfaces of the proximalcomponent with acetone to remove any potting or othermaterial that came into contact with the surface. Avoid allow-ing the acetone to contact the good potting material.8.3.3 Assemble the remainder of the implant, ensuring thatthe stem remains ali
36、gned properly in all planes of interest.8.3.4 Assemble the modular components of the stem bodyas specified by the surgical technique for the device.8.3.5 Place the femoral head on the neck taper of the hipimplant and impact the head on the taper with three blows witha rubber mallet.8.3.6 Determine t
37、he femoral head offset from the centerlineof the stem. This can be done by means of a height gauge oroptical comparator.8.4 Test Set-up:8.4.1 Attach the pivot fixture with the specimen to the testframe fixture in the correct orientation.8.4.2 Attach the polyethylene load applicator to the actuator.8
38、.4.3 Bring the load applicator into contact with the femoralhead of the specimen so that a low load (approximately 10 lbf)is applied.8.4.4 Vertically position the reaction bolt assembly so that itis located 66 mm from the pivot axis (Fig. 2). If the stem designincludes a coronal slot, the reaction b
39、olt should be locatedabove the highest level of the coronal slot.NOTE 1The vertical position of the reaction bolt may be modified toaccommodate designs and test purposes different from what is explainedin this test method.8.4.5 Adjust the main fixture and the pivot fixture so that thespecimen is ali
40、gned at the proper angles in the frontal plane(adduction) and in the sagittal plane (flexion) (See 6.1). Thetest setup is represented in Fig. 2.8.4.6 Proper measures should be taken to ensure that thefixturing is secure and the specimen or equipment does not getdamaged should unloading occur during
41、testing8.4.7 Test FrequencyRun all tests at a frequency of 10 Hzor less. constant frequency with a maximum allowable fre-quency of 10 Hz. Take care to ensure that the test machine canNOTEOnce assembled, the pivot axis will be coincident with the pointon the implant defined by the intersection of the
42、 neck and stem centerlines.FIG. 3 Proximal Sleeve Component Potted in Pivot FixtureF2580073maintain the applied load at the chosen frequency and thatresonant conditions are not reached.8.4.8 Input Loading ProfileRun all tests using a sinusoi-dal waveform input load with an R value of 10.0NOTE 2In st
43、rict terms, since the force applied to the femoral head iscompressive, the maximum force is the smallest negative amplitude.Consequently, the R value is ten when the negative signs cancel eachother. In terms of applied bending moment at the potting plane, the Rvalue would be 0.1. See Terminology E 1
44、150 for the definition of the Rvalue.9. Test Termination9.1 Continue the test until the femoral prosthesis fails oruntil a predetermined number of cycles have been applied tothe implant. The suggested number of cycles is ten million.Failure may be defined as: a fracture of the femoral implant;format
45、ion of a crack detectable by eye, fluorescent dyepenetrant, or other non-destructive means; or exceeding apredetermined deflection limit.10. Report10.1 Report the fatigue test specimens, procedures, andresults in accordance with Practice E 468.10.2 In addition, report the following parameters:10.2.1
46、 Femoral implant (size, configuration, material, andso forth),10.2.2 Femoral head size and offset,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 reactio
47、n 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 A precision and bias statemen
48、t does not exist for thistest method because round robin testing has not been per-formed.12. Keywords12.1 arthroplasty; femoral hip prostheses; orthopedic medi-cal devices; proximal fixation; total hip arthroplastyAPPENDIX(Nonmandatory Information)X1. RATIONALEX1.1 It is recognized that for some mat
49、erials the environ-ment may have an effect on the response to cyclic loading. Thetest environment used and the rationale for that choice shall bedescribed in the test report.X1.2 It is also recognized that the actual in vivo loadingconditions are not constant amplitude. However, there may beinsufficient information available to create standard load spec-trums for metallic femoral hip implants. Accordingly, a simpleperiodic constant amplitude force is recommended.X1.3 Worst-case loading of the hip implant may varydepending on material, design, and clinical indication
