1、Designation: F1714 96 (Reapproved 2018)Standard Guide forGravimetric Wear Assessment of Prosthetic Hip Designs inSimulator Devices1This standard is issued under the fixed designation F1714; the number immediately following the designation indicates the year oforiginal adoption or, in the case of rev
2、ision, 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 guide describes a laboratory method using aweight-loss technique for evaluating the wear prope
3、rties ofmaterials or devices, or both, which are being considered foruse as bearing surfaces of human-hip-joint replacement pros-theses. The hip prostheses are evaluated in a device intended tosimulate the tribological conditions encountered in the humanhip joint, for example, use of a fluid such as
4、 bovine serum, orequivalent pseudosynovial fluid shown to simulate similarwear mechanisms and debris generation as found in vivo, andtest frequencies of 1 Hz or less.1.2 Since the hip simulator method permits the use of actualimplant designs, materials, and physiological load/motioncombinations, it
5、can represent a more physiological simulationthan basic wear-screening tests, such as pin-on-disk (seePractice F732) or ring-on-disk (see ISO 6474).1.3 It is the intent of this guide to rank the combination ofimplant designs and materials with regard to material wear-rates, under simulated physiolog
6、ical conditions. It must berecognized, however, that there are many possible variations inthe in vivo conditions, a single laboratory simulation with afixed set of parameters may not be universally representative.1.4 The reference materials for the comparative evaluationof candidate materials, new d
7、evices, or components, or acombination thereof, shall be the wear rate of extruded orcompression-molded, ultra-high molecular weight (UHMW)polyethylene (see Specification F648) bearing against standardcounter faces stainless steel (see Specification F138); cobalt-chromium-molybdenum alloy (see Speci
8、fication F75); thermo-mechanically processed cobalt chrome (see SpecificationF799); alumina ceramic (see Specification F603), havingtypical prosthetic quality, surface finish, and geometry similarto those with established clinical history. These referencematerials will be tested under the same wear
9、conditions as thecandidate materials.1.5 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.6 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in
10、the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D883 Terminology Relating to PlasticsF75 Specification for Cobalt-28 Chro
11、mium-6 MolybdenumAlloy Castings and Casting Alloy for Surgical Implants(UNS R30075)F86 Practice for Surface Preparation and Marking of Metal-lic Surgical ImplantsF136 Specification for Wrought Titanium-6Aluminum-4Vanadium ELI (Extra Low Interstitial)Alloy for SurgicalImplant Applications (UNS R56401
12、)F138 Specification for Wrought 18Chromium-14Nickel-2.5Molybdenum Stainless Steel Bar and Wire for SurgicalImplants (UNS S31673)F370 Specification for Proximal Femoral Endoprosthesis(Withdrawn 2005)3F565 Practice for Care and Handling of Orthopedic Implantsand InstrumentsF603 Specification for High-
13、Purity Dense Aluminum Oxidefor Medical ApplicationF648 Specification for Ultra-High-Molecular-Weight Poly-ethylene Powder and Fabricated Form for Surgical Im-plantsF732 Test Method for Wear Testing of Polymeric MaterialsUsed in Total Joint Prostheses1This guide is under the jurisdiction of ASTM Comm
14、ittee F04 on Medical andSurgical Materials and Devices and is the direct responsibility of SubcommitteeF04.22 on Arthroplasty.Current edition approved April 1, 2018. Published May 2018. Originallyapproved in 1996. Last previous edition approved in 2013 as F1714 96 (2013).DOI: 10.1520/F1714-96R18.2Fo
15、r 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 refere
16、nced onwww.astm.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
17、Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1F799 Specification for Cobalt-28Chromium-6MolybdenumAlloy Forgings for Surgical Implants (UNS R31537,R31538, R31539)G40 Terminology Relating to Wear
18、and Erosion2.2 ISO Standard:ISO 6474 Implants for SurgeryCeramic Materials Based onAlumina43. Significance and Use3.1 This guide uses a weight-loss method of wear determi-nation for the polymeric components used with hip jointprostheses, using serum or demonstrated equivalent fluid forlubrication, a
19、nd running under a dynamic load profile repre-sentative of the human hip-joint forces during walking (1,2).5The basis for this weight-loss method for wear measurementwas originally developed (3) for pin-on-disk wear studies (seePractice F732) and has been extended to total hip replacements(4,5) femo
20、ral-tibial knee prostheses (6), and to femoropatellarknee prostheses (6,7).3.2 While wear results in a change in the physical dimen-sions of the specimen, it is distinct from dimensional changesdue to creep or plastic deformation, in that wear generallyresults in the removal of material in the form
21、of polymericdebris particles, causing a loss in weight of the specimen.3.3 This guide for measuring wear of the polymeric com-ponent is suitable for various simulator devices. These tech-niques can be used with metal, ceramic, carbon, polymeric, andcomposite counter faces bearing against a polymeric
22、 material(for example, polyethylene, polyacetal, and so forth). Thisweight-loss method, therefore, has universal application forwear studies of total hip replacements that feature polymericbearings. This weight-loss method has not been validated forhigh-density material bearing systems, such as meta
23、l-metal,carbon-carbon, or ceramic-ceramic. Progressive wear of suchrigid bearing combinations generally has been monitored usinga linear, variable-displacement transducers or by other profi-lometric techniques.4. Apparatus and Materials4.1 Hip Prosthesis ComponentsThe hip-joint prosthesiscomprises a
24、 ball-and-socket configuration in which materialssuch as polymers, composites, metal alloys, ceramics, andcarbon have been used in various combinations and designs.4.2 Component ConfigurationsThe diameter of the pros-thetic ball may vary from 22 to 54 mm or larger. The designmay include ball-socket,
25、 trunnion, bipolar, or other configura-tions.4.3 Hip Simulator:4.3.1 Test ChambersIn the case of a multi-specimenmachine, contain the components in individual, isolated cham-bers to prevent contamination of one set of components withdebris from another test. Ensure that the chamber is madeentirely o
26、f noncorrosive materials, such as acrylic plastic orstainless steel, and is easily removable from the machine forthorough cleaning between tests. Design the wear chamberssuch that the test bearing surfaces are immersed in the lubricantthroughout the test (3,7).4.3.2 Component Clamping FixturesSince
27、wear is to bedetermined from the weight-loss of the components, themethod for mounting the components in the test chambershould not compromise the accuracy of assessment of theweight-loss due to wear.4.3.3 LoadEnsure that the test load profile is representa-tive of that which occurs during the patie
28、nts walking cycle,with peak hip-loads 2kN(2). The loading apparatus shall befree to follow the specimen as wear occurs, so that the appliedload is constant to within 63 % for the duration of the test.Never allow the applied load to be below that required to keepthe chambers seated (for example, 50 N
29、) (4).4.3.4 MotionEnsure that relative motion between the hipcomponents oscillates and simulates the flexion-extension arcof walking. Addition of internal-external or abduction-adduction arcs is at the investigators discretion. It is recom-mended that the orientations of the cup and ball relative to
30、 eachother and to the load-axis be maintained by suitable specimen-holder keying.4.3.5 Oscillating FrequencyOscillate the hip prostheses ata rate of one cycle per second (1 Hz).4.3.6 Cycle CounterInclude a counter with the hip-simulator to record the total number of wear cycles.4.3.7 FrictionIt is r
31、ecommended that the machine includesensors capable of monitoring the friction forces transmittedacross the bearing surfaces during the wear test.4.4 Lubricant:4.4.1 It is recommended that the specimen be lubricatedwith bovine blood serum; however, another suitable lubricationmedium may be used if va
32、lidated.4.4.2 If serum is used, use filtered-sterilized serum ratherthan pooled serum since the former is less likely to containhemolyzed blood material, which has been shown to adverselyaffect the lubricating properties of the serum (3). Dilutedsolutions of serum have also been used for this purpos
33、e (8).Filtration may remove hard, abrasive, particulate contaminantsthat might otherwise affect the wear properties of the speci-mens being tested.4.4.3 Maintain the volume and concentration of the lubri-cant nearly constant throughout the test. This may be accom-plished by sealing the chambers so t
34、hat water does notevaporate, or periodically or continuously replacing evaporatedwater with distilled water.4.4.4 To retard bacterial degradation, freeze and store theserum until needed for the test. In addition, ensure that the fluidmedium in the test contains 0.2 % sodium azide (or othersuitable a
35、ntibiotic) to minimize bacterial degradation. Otherlubricants should be evaluated to determine appropriate storageconditions.4.4.5 It is recommended that ethylene-diaminetetraaceticacid (EDTA) be added to the serum at a concentration of 20mM to bind calcium in solution and minimize precipitation ofc
36、alcium phosphate onto the bearing surfaces. The latter event4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.5The boldface numbers in parentheses refer to the list of references at the end ofthis standard.F1714 96 (2018)2h
37、as been shown to strongly affect the friction and wearproperties, particularly of polyethylene/ceramic combinations.The addition of EDTA to other lubricant mediums should beevaluated.4.4.6 A lubricant other than bovine serum may be used if itcan be shown that its lubricating properties and, therefor
38、e,material wear properties are reasonably physiological (8).Insuch a case, specify the lubricant in the test report.4.5 Hold the bulk temperature of the lubricant at 37 6 3Cor as specified, if different.5. Specimen Preparation5.1 The governing rule for preparation of component coun-ter faces is that
39、 the fabrication process parallels that used orintended for use in the production of actual prostheses, in orderto produce a specimen with comparable bulk material proper-ties and surface characteristics (see Practice F86).5.2 Polymers and Composites:5.2.1 Obtain a fabrication history for each polym
40、eric orcomposite component, including information such as grade,batch number, and processing variables, including method offorming (extruding, molding, and so forth), temperature,pressure, and forming time used, and any post-formingtreatments, including sterilization.5.2.2 Pretest characterization m
41、ay include measurement ofbulk material properties, such as molecular-weight range anddistribution, percent crystallinity, density, or other. The surfacefinish of specimens may be characterized by profilometry,photomicrography, replication by various plastics, or othertechniques.5.2.3 SterilizationSt
42、erilize the components in a mannertypical of that in clinical use for such devices, including totaldose and dose rate, as these may affect the wear properties ofthe materials. Report these processing parameters with theaging time prior to each test when known. Sterilization of alltest and control co
43、mponents within a specific test group shouldbe done simultaneously (in a single container), when possible,to minimize variation among the specimens. This wear-simulation procedure makes no attempt to maintain the sterilityof specimens during the wear test.5.2.4 Cleaning of Polymer ProsthesesPrior to
44、 weartesting, careful cleaning of the polymer specimens is importantto remove any contaminants that would not normally bepresent on the actual prosthesis. During the wear run, thecomponents must be re-cleaned and dried before each weigh-ing to remove any extraneous material that might affect theaccu
45、racy of the weighing. A suggested procedure for cleaningand drying of polymeric components is given in Annex A4.With some combinations of materials, wear may result in thetransfer of particulate debris which may then become re-imbedded or otherwise attached to polymeric, metal, or com-posite surface
46、s. Such an occurrence will render the weight-lossassessment of wear less reliable.5.2.5 Weighing of Polymeric ComponentsWeigh the poly-meric components on an analytical balance having an accuracyon the order of 610 g. This degree of sensitivity is necessaryto detect the slight loss in weight of poly
47、mers, such as UHMWpolyethylene, which may wear 30 mg or less per million cycles(3,5).Always weigh specimens in the clean, dry condition (seeAnnex A1). Keep the components in a dust-free container andhandle with clean tools to prevent contamination that mightaffect the weight measurement. Weigh each
48、wear and controlcomponent three times in rotation to detect random errors inthe weighing process.5.3 Soaking of Polymeric and Composite Prostheses:5.3.1 Polymeric and composite components should be pre-soaked in the lubricant to minimize fluid sorption during thewear run. Without presoaking, compone
49、nts of very low-wearpolymers such as polyethylene may show a net increase inweight during the initial wear intervals, due to fluid sorption(3,4). The error due to fluid sorption can be reduced throughpresoaking and the use of control soak specimens. The numberof specimens required and the length of presoaking depends onthe variability and magnitude of fluid sorption encountered (4).5.3.2 After fabrication and characterization, clean and drythe wear components and three soak-control components ofeach test material in accordance with Annex A4, and thenweigh by pre
