1、Designation: F 543 071Standard Specification and Test Methods forMetallic Medical Bone Screws1This standard is issued under the fixed designation F 543; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A n
2、umber in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1NOTEUnits information was editorially corrected in August 2009.1.
3、Scope1.1 This specification provides requirements for materials,finish and marking, care and handling, and the acceptabledimensions and tolerances for metallic bone screws that areimplanted into bone. The dimensions and tolerances in thisspecification are applicable only to metallic bone screwsdescr
4、ibed in this specification.1.2 This specification provides performance considerationsand standard test methods for measuring mechanical propertiesin torsion of metallic bone screws that are implanted into bone.These test methods may also be applicable to other screwsbesides those whose dimensions an
5、d tolerances are specifiedhere. The following annexes are included:1.2.1 Annex A1Test Method for Determining the Tor-sional Properties of Metallic Bone Screws.1.2.2 AnnexA2Test Method for Driving Torque of Medi-cal Bone Screws.1.2.3 Annex A3Test Method for Determining the AxialPullout Strength of Me
6、dical Bone Screws.1.2.4 Annex A4Test Method for Determining the Self-Tapping Performance of Self-Tapping Medical Bone Screws.1.2.5 Annex A5Specifications for Type HA and Type HBMetallic Bone Screws.1.2.6 Annex A6Specifications for Type HC and Type HDMetallic Bone Screws.1.2.7 Annex A7Specifications
7、for Metallic Bone ScrewDrive Connections.1.3 This specification is based, in part, upon ISO 5835, ISO6475, and ISO 9268.1.4 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.5 This standard may involve the use of hazardous mate-
8、rials, operations, and equipment. This standard does notpurport to address all of the safety concerns, if any, associatedwith its use. It is the responsibility of the user of this standardto establish appropriate safety and health practices anddetermine the applicability of regulatory limitations pr
9、ior touse.2. Referenced Documents2.1 ASTM Standards:2E4 Practices for Force Verification of Testing MachinesE6 Terminology Relating to Methods of Mechanical Test-ingE8 Test Methods for Tension Testing of Metallic MaterialsE 122 Practice for Calculating Sample Size to Estimate,With Specified Precisio
10、n, the Average for a Characteristicof a Lot or ProcessF67 Specification for Unalloyed Titanium, for SurgicalImplant Applications (UNS R50250, UNS R50400, UNSR50550, UNS R50700)F86 Practice for Surface Preparation and Marking of Me-tallic Surgical ImplantsF116 Specification for Medical Screwdriver Bi
11、tsF 136 Specification for Wrought Titanium-6Aluminum-4Vanadium ELI (Extra Low Interstitial) Alloy for SurgicalImplant Applications (UNS R56401)F 138 Specification for Wrought 18Chromium-14Nickel-2.5Molybdenum Stainless Steel Bar and Wire for SurgicalImplants (UNS S31673)F 565 Practice for Care and H
12、andling of Orthopedic Im-plants and InstrumentsF 620 Specification for Alpha Plus Beta Titanium AlloyForgings for Surgical Implants1This specification is under the jurisdiction of ASTM Committee F04 onMedical and Surgical Materials and Devices and is the direct responsibility ofSubcommittee Osteosyn
13、thesis.Current edition approved June 1, 2007. Published June 2007. Originallyapproved in 1977. Last previous edition approved in 2002 as F 543 021.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandard
14、s volume information, 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.F 799 Specification for Cobalt-28Chromium-6MolybdenumAlloy Forgings for Surgical Implants (UNS R315
15、37,R31538, R31539)F 983 Practice for Permanent Marking of Orthopaedic Im-plant ComponentsF 1295 Specification for Wrought Titanium-6Aluminum-7Niobium Alloy for Surgical Implant Applications (UNSR56700)F 1314 Specification for Wrought Nitrogen Strengthened 22Chromium 13 Nickel 5 Manganese 2.5 Molybde
16、numStainless Steel Alloy Bar and Wire for Surgical Implants(UNS S20910)F 1472 Specification for Wrought Titanium-6Aluminum-4Vanadium Alloy for Surgical Implant Applications (UNSR56400)F 1537 Specification for Wrought Cobalt-28Chromium-6MolybdenumAlloys for Surgical Implants (UNS R31537,UNS R31538, a
17、nd UNS R31539)F 1586 Specification for Wrought Nitrogen Strengthened21Chromium10Nickel3Manganese2.5Molybdenum Stainless Steel Alloy Bar for SurgicalImplants (UNS S31675)F 1713 Specification for Wrought Titanium-13Niobium-13Zirconium Alloy for Surgical Implant Applications(UNS R58130)F 1813 Specifica
18、tion for Wrought Titanium12 Molybde-num6 Zirconium2 IronAlloy for Surgical Implant (UNSR58120)F 1839 Specification for Rigid Polyurethane Foam for Useas a Standard Material for Testing Orthopaedic Devicesand Instruments2.2 ISO Standards:5835 Implants for SurgeryMetal Bone Screws with Hex-agonal Driv
19、er Connection, Spherical Under Surface ofHead, Asymmetrical ThreadDimensions36475 Implants for SurgeryMetal Bone Screws withAsymmetrical Thread and Spherical Under-SurfaceMechanical Requirements and Test Methods39268 Implants for SurgeryMetal Bone Screws with Coni-cal Under-Surface of HeadDimensions
20、33. Terminology3.1 DefinitionsSome of the terms defined in this sectionare shown in Fig. 1.3.1.1 axial pullout strengththe tensile force required tofail or remove a bone screw from a material into which thescrew has been inserted.3.1.2 breaking angleangle of rotation when the screwfails in torsion a
21、s demonstrated by a rapid decrease in theindicated torque.3.1.3 buttress threadan asymmetrical thread profile char-acterized by a pressure flank which is nearly perpendicular tothe screw axis.3.1.4 cancellous screwa screw designed primarily to gainpurchase into cancellous bone. Cancellous screws typ
22、icallyhave a HB thread and may or may not be fully threaded.3.1.5 cortical screwa screw designed primarily to gainbiocortical purchase into cortical bone. Cortical screws typi-cally have a HA thread and are fully threaded.3.1.6 core diameterthe smallest diameter of the threadedportion of the screw m
23、easured at the thread root. This is alsoknown as the minor diameter or root diameter.3.1.7 gage lengththe distance between the holding device,for example, a split collet, and the underside of the screw head.3.1.8 grip lengththe length of threads held fast in the splitcollet or other holding mechanis
24、m.3.1.9 insertion depththe threaded length as inserted intothe test block.3.1.10 insertion torquethe amount of torque required toovercome the frictional force between the screw and thematerial used for testing while driving the screw into thematerial.3.1.11 maximum torque (N-m)the largest value of t
25、orquerecorded during the period of rotation before screw failure intorsional shear when tested in accordance with Annex A1.3.1.12 nontapping screwa screw that has a tip that doesnot contain a flute. Nontapping screws usually require a tap tobe inserted into the pilot hole before the insertion of the
26、 screw,when used in moderate or hard bone.3.1.13 partially threaded screwa screw whose threadedportion does not extend fully from the screw point to the screwhead but instead has a smooth shaft running between the headand threads.3.1.14 pilot holethe hole drilled into the bone into whichthe screw ti
27、p is inserted. The pilot hole is normally slightlylarger than the screws core diameter. However, if the screw isto be used to provide compression across a fracture, a portionof the pilot hole may be larger to allow for a clearance fit.3.1.15 pitchthe length between the thread crests.3.1.16 removal t
28、orquethe amount of torque required toovercome the frictional force between the screw and thematerial used for testing while removing the screw from thematerial (for example, counterclockwise rotation for right-handthread).3.1.17 screw headthe end of the screw which is oppositeof the tip and from whi
29、ch the means of inserting the screw iscoupled.3.1.18 screw lengththe overall length of the screw mea-sured from the screw head to the screw tip.3Available from American National Standards Institute, 25 W. 43rd St., 4thFloor, New York, NY 10036.FIG. 1 Schematic of Screw TermsF54307123.1.19 screw thre
30、ada helical groove on a cylindrical orconical surface. The projecting helical ridge thus formed iscalled a screw thread, consisting of peaks (crests) and valleys(roots).3.1.20 self-tapping force (N)the amount of axial forcerequired to engage the self-tapping features of self-tappingstyle screws when
31、 tested in accordance with Annex A4.3.1.21 self-tapping screwa screw that has any number offlutes at its tip which are intended to cut the screws threadform into the bone upon insertion.3.1.22 sizean identification of a screw based on its nomi-nal thread diameter, as defined in Section 6.3.1.23 soli
32、d corea screw that does not contain a cannula-tion along its longitudinal axis.3.1.24 thread diameterthe largest diameter of thethreaded portion of the screw measured over the thread crests.This is also known as the major diameter.3.1.25 thread lengththe length of the threaded portion ofthe screw, m
33、easured from the thread runout to the screw tip.3.1.26 thread runoutthe intersection of the screw threadwith either the screw shaft or screw head.3.1.27 torsional yield strength (N-m)the point at whichthe screw reaches its proportional limit when tested in accor-dance with Annex A1. This will be det
34、ermined by the offsetmethod. A 2 offset value will be used.4. Classification4.1 There are a large variety of medical bone screwscurrently in use. They may be classified by the definitionsprovided in Section 3. This specification currently includesinformation that defines the following types of screw
35、s:4.1.1 Type HASpherical undersurface of head, shallow,asymmetrical buttress thread, and deep screw head.4.1.2 Type HBSpherical undersurface of head, deep,asymmetrical buttress thread, and shallow screw head.4.1.3 Type HCConical undersurface of head, symmetricalthread.4.1.4 Type HDConical undersurfa
36、ce of head, asymmetri-cal thread.5. Material5.1 Screws shall be fabricated from one of the followingmaterials:5.1.1 Stainless steel alloy (Specification F 138).5.1.2 Nitrogen-strengthened stainless steel alloy (Specifica-tions F 1314 and F 1586).5.1.3 Unalloyed titanium (Specification F67).5.1.4 Tit
37、anium-aluminum-vanadium alloy (SpecificationsF 136, F 620, and F 1472).5.1.5 Titanium-aluminum-niobium alloy (SpecificationF 1295).5.1.6 Titanium-niobium-zirconium alloy (SpecificationF 1713).5.1.7 Cobalt-chromium-molybdenum alloy (SpecificationsF 799 and F 1537).5.1.8 Titanium-molybdenum-zirconium-
38、iron alloy (Specifi-cation F 1813).6. Dimensions and Tolerances6.1 There are many types of metallic bone screw designsavailable, so a complete list of dimensions and tolerances forall screws covered by this specification is unfeasible. However,this specification does provide required dimensions and
39、toler-ances for four types of screws as classified in 4.1. Screwsconforming to this specification, and designated HA, HB, HC,or HD screws, shall be fabricated in accordance with thedimensions and tolerances described in Annex A5 and AnnexA6, respectively.7. Finish and Marking7.1 The screw shall be f
40、ree from nicks, dents, burrs, andscratches when examined in accordance with Practice F 86.7.2 When size permits, the following information should belegibly marked on the head of the screw (in order of prefer-ence):7.2.1 Manufacturers name or logo,7.2.2 Screw SizeIf a screw is manufactured in accorda
41、ncewith ASTM or ISO specifications, the ASTM or ISO designa-tion should be provided,7.2.3 Material,7.2.4 Catalog number, and7.2.5 Manufacturing lot number.7.3 Screws shall be marked in accordance with PracticeF 983, unless otherwise specified in 7.2, in a manner such thatthe mechanical integrity of
42、the screw is not compromised.8. Care and Handling8.1 Screws should be cared for and handled in accordancewith Practice F 565, as appropriate.9. Driving Instruments9.1 A variety of screwdrivers exist for the insertion andremoval of bone screws. The classification and dimensions forvarious screw-drive
43、 recesses currently used in the medicalindustry are documented in Annex A7. Specification F116provides related dimensional information for several types ofmedical screwdrivers.9.2 Screws conforming to this specification, and designatedHA, HB, HC, or HD screws, shall be manufactured with driverecesse
44、s that conform to the requirements specified in AnnexA5 and Annex A6, respectively.10. Performance Considerations and Test Methods10.1 The following properties may be important whendetermining the suitability of a screw for a particular applica-tion. However, the test methods referenced as follows m
45、ay notbe appropriate for all types of implant applications. The user iscautioned to consider the appropriateness of the test methods inview of the devices being tested and their potential application.10.1.1 Torsional StrengthThis test method is an importantparameter to prevent screw breakage during
46、insertion orremoval. The torsional strength shall be determined using thetest methods described in Annex A1.10.1.2 Breaking AngleThis test method provides a mea-sure of the ductility of the screw when undergoing a torsionalmoment.Ascrew with a greater breaking angle may provide anF5430713earlier tac
47、tile warning to the surgeon that the screw is reachingits maximum torsional strength. The breaking angle shall bedetermined using the test methods described in Annex A1.10.1.3 Axial Pullout StrengthThis test method may be animportant parameter if the screw is subjected to axial tensileforces, or if
48、the screw is fixed into poor quality or osteoporoticbone. The pullout strength may be determined using the testmethods described in Annex A3.10.1.4 Insertion TorqueThis test method may be an im-portant parameter to avoid failure of the screw during insertionand to ensure that the screw may be easily
49、 inserted by thesurgeon. The insertion torque should be much less thantorsional yield strength of the screw and of the appropriatescrewdriver bit. The insertion torque may be determined usingthe test methods described in Annex A2.10.1.5 Removal TorqueThis test method may be an im-portant parameter to avoid failure of the screw during removaland to ensure that the screw may be easily removed by thesurgeon. The removal torque should be much less than tor-sional yield strength of the screw and of the appropriatesc
