1、Designation: F564 10Standard Specification and Test Methods forMetallic Bone Staples1This standard is issued under the fixed designation F564; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year of last revision. A number in p
2、arentheses indicates the year of last reapproval. A superscriptepsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This specification covers characterization of the designand mechanical function of metallic staples used in the internalfixation of the muscular s
3、keletal system. It is not the intentionof this specification to describe or specify specific designs formetallic bone staples.1.2 This specification includes the following four test meth-ods for measuring mechanical properties of metallic bonestaples:1.2.1 Test Method for Constant Amplitude Bending
4、FatigueTests of Metallic Bone StaplesAnnex A1.1.2.2 Test Method for Pull-Out Fixation Strength of Metal-lic Bone StaplesAnnex A2.1.2.3 Test Method for Soft Tissue Fixation Strength ofMetallic Bone StaplesAnnex A3.1.2.4 Test Method for Elastic Static Bending of MetallicBone StaplesAnnex A4.1.3 The va
5、lues 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 s
6、afety 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 MachinesE122 Practice for Calculating Sample Size to Estimate,With Specified Precision, the Average for a Chara
7、cteristicof a Lot or ProcessE467 Practice for Verification of Constant Amplitude Dy-namic Forces in an Axial Fatigue Testing SystemF75 Specification for Cobalt-28 Chromium-6 MolybdenumAlloy Castings and Casting Alloy for Surgical Implants(UNS R30075)F86 Practice for Surface Preparation and Marking o
8、f Me-tallic Surgical ImplantsF382 Specification and Test Method for Metallic BonePlatesF565 Practice for Care and Handling of Orthopedic Im-plants and InstrumentsF601 Practice for Fluorescent Penetrant Inspection of Me-tallic Surgical ImplantsF629 Practice for Radiography of Cast Metallic SurgicalIm
9、plants3. Finish3.1 Staples conforming to this specification shall be finishedand identified in accordance with Practice F86, as appropriate.4. Inspection Practices4.1 Staples made in accordance with Specification F75should be inspected in accordance with Practice F601 orX-rayed in accordance with Pr
10、actice F629.5. Care and Handling5.1 Staples should be cared for and handled in accordancewith Practice F565, as appropriate.6. Keywords6.1 bending test; bone fixation; fatigue test; fixation devices;metallic bone staples; orthopaedic medical devices; pullouttest; soft tissue fixation; surgical impla
11、nts1This specification is under the jurisdiction of ASTM Committee F04 onMedical and Surgical Materials and Devices and is the direct responsibility ofSubcommittee F04.21 on Osteosynthesis.Current edition approved Sept. 1, 2010. Published September 2010. Originallyapproved in 1985. Last previous edi
12、tion approved in 2006 as F564 02 (2006)1.DOI: 10.1520/F0564-10.2For 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 websit
13、e.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.ANNEXES(Mandatory Information)A1. TEST METHOD FOR CONSTANT AMPLITUDE BENDING FATIGUE TESTS OF METALLIC BONE STAPLESA1.1 ScopeA1.1.1 This test method covers procedures for the perfor-m
14、ance of constant amplitude fatigue testing of metallic staplesused in internal fixation of the musculoskeletal system. Thistest method may be used when testing in air at ambienttemperature or in an aqueous or physiological solution.A1.1.2 The values stated in SI units are to be regarded asstandard.
15、No other units of measurement are included in thisstandard.A1.1.3 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
16、-bility of regulatory limitations prior to use.A1.2 Summary of Test MethodA1.2.1 Metallic bone staples are tested under bending loadsuntil the specimen fails or a predetermined number of cycleshas been applied to it. Bending tests may be performed in oneof two modes: either pure, in-plane bending; o
17、r tension (orcompression) combined with in-plane bending. Tests usingeither of these methods may be conducted at ambient condi-tions or in aqueous or physiological solutions (at either roomtemperature or 37C).A1.3 Significance and UseA1.3.1 This test method is used to determine the fatigueresistance
18、 of metallic bone staples when subjected to repetitiveloading for large numbers of cycles. This information may alsobe useful for comparing the effect of variations in staplematerial, geometry, surface condition, or placement undercertain circumstances.A1.3.2 It is essential that uniform fatigue pra
19、ctices beestablished in order that such basic fatigue data be comparableand reproducible and can be correlated among laboratories.A1.3.3 The results of fatigue tests are suitable for directapplication to design only when the service conditions parallelthe test conditions exactly. This test method ma
20、y not beappropriate for all types of bone staple applications. The useris cautioned to consider the appropriateness of the test methodin view of the materials being tested and their potentialapplication.A1.4 ApparatusA1.4.1 Testing Machines, conforming to the requirements ofPractices E4 and E467. Th
21、e loads used for determiningstrengths shall be within the loading range of the testingmachine as defined in Practices E4 and E467.A1.4.2 Gripping Devices:A1.4.2.1 Staple ExtensionsPairs of specially designedmetal blocks that permit the holding of individual staples forthe application of bending fati
22、gue loads. The legs of each stapleare fitted into fixation holes in each block with minimalclearance to restrict bending of the staple within the hole. Thestaple is fixed securely in the block using a moldable filling orgrouting agent. The extension design should minimize theweight to reduce the inf
23、luence on the staple while maintainingsufficient stiffness to transfer the load to the staple withoutundesirable deflection. Holes for pin and clevis fixation areoptional (see Figs. A1.1-A1.3).NOTE A1.1Variations in fixation hole configuration may be requiredfor staple legs with noncircular cross se
24、ctions. Also, it is necessary toprovide a gap between the underside of the staple bridge and edge of thestaple extender in most cases. This is necessary to eliminate contactbetween the staple bridge (or other bridge features such as tissue spikes)and the staple extender. However, this gap should be
25、standardized withinany test group as required.A1.4.2.2 4-Point Bend FixtureA standard or modifiedbending fixture that produces pure bending in the staplewithout appreciable shear or torsion when used to apply load tothe staple through the staple extensions.A1.4.2.3 Pin and Clevice FixtureA standard
26、or modifiedfixture used to apply a distractive or compressive load to thestaple through the staple extensions to produce bending in thestaple similar to that seen in vivo.A1.4.3 Filling or Grouting AgentA stiff, moldable filler,such as epoxy, acrylic cement, or a low-melting point alloy (forexample,
27、 Woods metal) used to secure the staple leg within thestaple extension.A1.4.4 Aqueous SolutionTap water, distilled water, physi-ological saline, or similar aqueous solutions, used to immersethe test specimens fully during the test.FIG. A1.1 4-Point Bending of Staples in ExtensionF564 102A1.4.5 Const
28、ant Temperature BathAn aqueous bath ca-pable of maintaining the samples and containers at physiologictemperatures, 37 6 2C, for the specified testing periods.A1.5 Test SpecimenA1.5.1 StapleA generally U-shaped metal loop, with atleast two legs, that is driven into the surface of bone to eitherfix or
29、 immobilize adjacent pieces of bone or to fasten softtissue or other material to bone. All test samples shall berepresentative of the material under evaluation. Samples forcomparative tests shall be produced from the same material lotor batch and under the same fabricating conditions, unlessnoted sp
30、ecifically.A1.5.2 Staple LegThe parallel or nearly parallel exten-sions that are intended to penetrate the bone tissue; these maybe round, square, or polygonal in cross section, and they maypossess serrations or barbs to increase the fixation or purchasestrength in the bone.A1.5.3 Staple BridgeThe c
31、ross member of the stapleconnecting the legs; the bridge may be smooth or possessspikes or projections on the underside for the retention of softtissue or other material.A1.6 ProcedureA1.6.1 Mounting the SpecimenFix the staple leg in anextension block using the filling agent.Afixture should be usedt
32、o ensure proper in-plane alignment of the two extensions andthe staple during this process. Also, each staple should be fixedsuch that the bridge is the same distance from the top of eachextension.NOTE A1.2This distance is at the discretion of the operator, but itdetermines the portion of the staple
33、 subjected to the bending loads.A1.6.2 4-Point Bend Testing:A1.6.2.1 Place the staple and attached staple extensions inthe 4-point bending fixture such that the loading point andsupport rollers contact the staple extensions on either side ofthe staple; direct contact of the rollers with the staple s
34、hall notbe permitted during the test. Alignment of the loading pointrollers shall be symmetric on the centerline between thesupport rollers (see Fig. A1.1).A1.6.2.2 Apply cyclic loads (sinusoidal, sawtooth, and soforth), generating bending moments in the staple withoutpermanent deformation. Appropri
35、ate starting loads should be50 to 75 % of the static bending strength, unless indicatedotherwise.NOTE A1.3It may be necessary to provide a low-friction means ofmaintaining the position of the staple and attached extensions. Also, thefixtures should be designed so that loads are applied equally at th
36、e loadingpoints during each deflection throughout the test.A1.6.2.3 Compute the bending moment, M, by the follow-ing formula, where F = force applied at each loading point andA = distance between the loading point and support roller,Mbending= FA.A1.6.2.4 Continue the test until failure of the staple
37、, thefixation, or a predetermined number of load cycles has beenapplied.A1.6.3 Combined Tension or (Compression) and Bending:A1.6.3.1 Place the staple and attached staple extensions inthe axial bending fixture. The pins and clevices should permitfree rotation of the staple extensions, with minimal f
38、riction,while maintaining alignment of the staple legs (and extensions)in the same plane (see Fig. A1.2).A1.6.3.2 Apply cyclic loads (sinusoidal, sawtooth, and soforth), generating bending moments in the staple withoutpermanent deformation. Appropriate starting loads should be50 to 75 % of the stati
39、c yield strength, unless indicatedotherwise.NOTE A1.4It may be necessary to maintain a minimum tensile orcompressive load on the specimen throughout the test, since operating atFIG. A1.2 Combined Tension (or Compression) and Bending ofStaplesFIG. A1.3 Diagram of Extender-Staple Forces Under Combined
40、Bending and TensionF564 103or near zero load may result in either loss of machine control due todiscontinuity in the load feedback loop or undesirable transient loading ofthe staple.A1.6.3.3 Compute the bending moment in the staple bridge,M, by the following formula, where F = force applied at eachc
41、enter of each pin and L = distance between the load applica-tion axis, that is, the pin center, and the neutral axis of thestaple bridge, Mbending= FL (see Fig. A1.3).NOTE A1.5The application of this test method produces bending,tensile (or compressive), and shear stresses in the staple. The directi
42、on andmagnitudes of these stresses should be analyzed using superpositiontheory or other suitable methods.A1.6.3.4 Continue the test until failure of the staple or thefixation or a predetermined number of load cycles has beenapplied.A1.6.4 Stress VerificationIt is recommended that straingages (or ex
43、tensometry) be used to measure the bending strainsinduced in the specimen. This is accomplished most easily onthe staple bridge, but it may be possible to perform on a portionof the staple leg or at the leg-bridge junction under certaincircumstances and with certain staple designs. The recom-mended
44、technique is to strain gage the actual fatigue testspecimens, if possible, provided that the installation of straingage will not influence the test results.A1.7 Test TerminationA1.7.1 Continue the tests until the specimen fails or apredetermined number of cycles has been applied to thespecimen. Fail
45、ure should be defined as complete separation, acrack visible at a specified magnification, a crack of certaindimensions, or by some other criterion. State the criterionselected for defining failure when reporting the results.A1.7.2 A test shall be considered invalid if loosening of thestaple occurs
46、in the embedding medium, if noticeable yieldingoccurs, or permanent deformation occurs in the specimen.A1.8 ReportA1.8.1 Report the following information:A1.8.1.1 Staple DescriptionType, size, special features(barbs, spikes, and so forth), manufacturer, material, batch orlot number, and dimensions (
47、including leg length, bridgewidth, and length), as appropriate.A1.8.1.2 Test Type4-point or combined tension (or com-pression) and bending.A1.8.1.3 Fixation GeometryLoad point separation dis-tances (4-point bending), load offset distance (combined ten-sion and bending), staple bridge-extension dista
48、nce, and soforth.A1.8.1.4 Minimum and maximum cycle loads, test fre-quency (for example, cycles/s), and forcing function type (sine,ramp, saw tooth, and so forth).A1.8.1.5 Bending moment, M (N-m).A1.8.1.6 Load ratio, R, where R = minimum load/maximumload.A1.8.1.7 Test EnvironmentAmbient air or physi
49、ologicalsolution.A1.8.1.8 Number of cycles at failure or test termination(runout).A1.8.1.9 Location of fatigue fracture (if applicable).A1.8.1.10 Reason for test termination, that is, staple failure,fixation failure, runout to specified cycle limit, and so forth.A1.9 PrecisionA1.9.1 Intralaboratory and interlaboratory reproducibilityhave not been determined systematically.A1.10 Rationale (Nonmandatory Information)A1.10.1 This test method is intended to aid in characterizingthe fatigue behavior of metallic bone staples used for thefixation of bone to bon
