ASTM F564-2002(2006)e1 Standard Specification and Test Methods for Metallic Bone Staples.pdf

1、Designation: F 564 02 (Reapproved 2006)1Standard Specification and Test Methods forMetallic Bone Staples1This standard is issued under the fixed designation F 564; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last re

2、vision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1NOTEUnits information was editorially corrected in September 2009.1. Scope1.1 This specification covers characterization of the designan

3、d mechanical function of metallic staples used in the internalfixation of the muscular skeletal 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 mechani

4、cal properties of metallic bonestaples:1.2.1 Test Method for Constant Amplitude Bending 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

5、.1.2.4 Test Method for Elastic Static Bending of MetallicBone StaplesAnnex A4.1.3 The values 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 i

6、ts 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:2E4 Practices for Force Verification of Testing MachinesE 122 Practice

7、for Calculating Sample Size to Estimate,With Specified Precision, the Average for a Characteristicof a Lot or ProcessE 467 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

8、 Alloy for Surgical Implants(UNS R30075)F86 Practice for Surface Preparation and Marking of Me-tallic Surgical ImplantsF 382 Specification and Test Method for Metallic BonePlatesF 565 Practice for Care and Handling of Orthopedic Im-plants and InstrumentsF 601 Practice for Fluorescent Penetrant Inspe

9、ction of Me-tallic Surgical ImplantsF 629 Practice for Radiography of Cast Metallic SurgicalImplants3. 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 Specifi

10、cation F75should be inspected in accordance with Practice F 601 orX-rayed in accordance with Practice F 629.5. Care and Handling5.1 Staples should be cared for and handled in accordancewith Practice F 565, as appropriate.6. Keywords6.1 bending test; bone fixation; fatigue test; fixation devices;meta

11、llic bone staples; orthopaedic medical devices; pullouttest; soft tissue fixation; surgical implants1This 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 editio

12、n approved March 1, 2006. Published April 2006. Originallyapproved in 1985. Last previous edition approved in 2002 as F 564 02.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information

13、, refer to the standards Document Summary page onthe ASTM website.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

14、 ScopeA1.1.1 This test method covers procedures for the perfor-mance 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

15、.2 The values stated in SI units are to be regarded asstandard. 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 ap

16、pro-priate safety and health practices and determine the applica-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 b

17、e performed in oneof two modes: either pure, in-plane bending; or 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

18、.3.1 This test method is used to determine the fatigueresistance 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 undercerta

19、in circumstances.A1.3.2 It is essential that uniform fatigue practices 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 con

20、ditions parallelthe test conditions exactly. This test method may 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 Mach

21、ines, conforming to the requirements ofPractices E4 and E 467. The loads used for determiningstrengths shall be within the loading range of the testingmachine as defined in Practices E4and E 467.A1.4.2 Gripping Devices:A1.4.2.1 Staple ExtensionsPairs of specially designedmetal blocks that permit the

22、 holding of individual staples forthe application of bending fatigue 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.

23、 The extension design should minimize theweight to reduce the influence 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 confi

24、guration may be requiredfor staple legs with noncircular cross sections. 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 ti

25、ssue spikes)and the staple extender. However, this gap should be 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

26、the staple extensions.A1.4.2.3 Pin and Clevice FixtureA standard 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

27、 epoxy, acrylic cement, or a low-melting point alloy (forexample, 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.

28、 A1.1 4-Point Bending of Staples in ExtensionF 564 02 (2006)12A1.4.5 Constant 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

29、 atleast two legs, that is driven into the surface of bone to eitherfix or 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 mate

30、rial lotor batch and under the same fabricating conditions, unlessnoted specifically.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 incre

31、ase the fixation or purchasestrength in the bone.A1.5.3 Staple BridgeThe cross 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

32、 leg in anextension block using the filling agent.Afixture should be usedto 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

33、the discretion of the operator, but itdetermines the portion of the staple 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

34、 either side ofthe staple; direct contact of the rollers with the staple shall 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), gener

35、ating bending moments in the staple withoutpermanent deformation. Appropriate 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. Al

36、so, thefixtures should be designed so that loads are applied equally at the 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

37、roller,Mbending= FA.A1.6.2.4 Continue the test until failure of the staple or 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 c

38、levices should permitfree rotation of the staple extensions, with minimal friction,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 withoutpermane

39、nt deformation. Appropriate starting loads should be50 to 75 % of the static 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

40、Bending ofStaplesFIG. A1.3 Diagram of Extender-Staple Forces Under CombinedBending and TensionF 564 02 (2006)13or 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 momen

41、t in the staple bridge,M, by the following formula, where F = force applied at eachcenter 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 prod

42、uces bending,tensile (or compressive), and shear stresses in the staple. The direction 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

43、 has beenapplied.A1.6.4 Stress VerificationIt is recommended that straingages (or extensometry) 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 ju

44、nction under certaincircumstances and with certain staple designs. The recom-mended 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 spe

45、cimen fails or apredetermined number of cycles has been applied to thespecimen. Failure 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

46、 results.A1.7.2 A test shall be considered invalid if a loosening ofthe staple occurs in the embedding medium or if noticeableyielding 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, spi

47、kes, and so forth), manufacturer, material, batch orlot number, and dimensions (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), loa

48、d offset distance (combined ten-sion and bending), staple bridge-extension distance, 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,

49、where R = minimum load/maximumload.A1.8.1.7 Test EnvironmentAmbient air or physiologicalsolution.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 characteriz