1、Designation: F 1541 02 (Reapproved 2007)1Standard Specification and Test Methods forExternal Skeletal Fixation Devices1This standard is issued under the fixed designation F 1541; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、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.1NOTEUnits information was editorially corrected in August 2009.1. Scope1.1 This specification provides a characterization
3、 of thedesign and mechanical function of external skeletal fixationdevices (ESFDs), test methods for characterization of ESFDmechanical properties, and identifies needs for further devel-opment of test methods and performance criteria. The ultimategoal is to develop a specification, which defines pe
4、rformancecriteria and methods for measurement of performance-relatedmechanical characteristics of ESFDs and their fixation to bone.It is not the intention of this specification to define levels ofperformance or case-specific clinical performance of the de-vices, as insufficient knowledge is availabl
5、e to predict theconsequences of the use of any of these devices in individualpatients for specific activities of daily living. Furthermore, it isnot the intention of this specification to describe or specifyspecific designs for ESFDs.1.2 This specification describes ESFDs for surgical fixationof the
6、 skeletal system. It provides basic ESFD geometricaldefinitions, dimensions, classification, and terminology; mate-rial specifications; performance definitions; test methods; andcharacteristics determined to be important to the in-vivoperformance of the device.1.3 This specification includes a termi
7、nology and classifi-cation annex and five standard test method annexes as follows:1.3.1 Classification of External FixatorsAnnex A1.1.3.2 Test Method for External Skeletal FixatorConnectorsAnnex A2.1.3.3 Test Method for Determining In-Plane CompressiveProperties of Circular Ring or Ring Segment Brid
8、geElementsAnnex A3.1.3.4 Test Method for External Skeletal Fixator JointsAnnex A4.1.3.5 Test Method for External Skeletal Fixator Pin Anchor-age ElementsAnnex A5.1.3.6 Test Method for External Skeletal FixatorSubassembliesAnnex A6.1.3.7 Test Method for External Skeletal Fixator/ConstructsSubassembli
9、esAnnex A7.1.4 A rationale is given in Appendix X1.1.5 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.6 The following safety hazards caveat pertains only to thetest method portions (Annex A2-Annex A6):1.7 This standard does n
10、ot 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-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standar
11、ds:2A 938 Test Method for Torsion Testing of WireD 790 Test Methods for Flexural Properties of Unreinforcedand Reinforced Plastics and Electrical Insulating MaterialsE4 Practices for Force Verification of Testing MachinesF67 Specification for Unalloyed Titanium, for SurgicalImplant Applications (UNS
12、 R50250, UNS R50400, UNSR50550, UNS R50700)F90 Specification for Wrought Cobalt-20Chromium-15Tungsten-10Nickel Alloy for Surgical Implant Applica-tions (UNS R30605)F 136 Specification for Wrought Titanium-6Aluminum-4Vanadium ELI (Extra Low Interstitial) Alloy for SurgicalImplant Applications (UNS R5
13、6401)F 138 Specification for Wrought 18Chromium-14Nickel-2.5Molybdenum Stainless Steel Bar and Wire for SurgicalImplants (UNS S31673)F 366 Specification for Fixation Pins and WiresF 543 Specification and Test Methods for Metallic MedicalBone Screws1This specification is under the jurisdiction of AST
14、M Committee F04 onMedical and Surgical Materials and Devices and is the direct responsibility ofSubcommittee F04.21 on Osteosynthesis.Current edition approved June 15, 2007. Published June 2007. Originallypublished as F 1541 94. Last previous edition approved in 2002 as F 1541 02.2For referenced AST
15、M 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.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshoho
16、cken, PA 19428-2959, United States.F 544 Reference Chart for Pictorial Cortical Bone ScrewClassification3F 1058 Specification for Wrought 40Cobalt-20Chromium-16Iron-15Nickel-7Molybdenum Alloy Wire and Strip forSurgical Implant Applications (UNS R30003 and UNSR30008)F 1264 Specification and Test Meth
17、ods for IntramedullaryFixation DevicesF 1472 Specification for Wrought Titanium-6Aluminum-4Vanadium Alloy for Surgical Implant Applications (UNSR56400)F 1713 Specification for Wrought Titanium-13Niobium-13Zirconium Alloy for Surgical Implant Applications(UNS R58130)3. Terminology3.1 DefinitionsThe d
18、efinitions of terms relating to exter-nal fixators are described in Annex A1.4. Classification4.1 External skeletal fixators are modular devices assembledfrom component elements.4.2 Test methods can address individual elements, for ex-ample, anchorage elements, bridge elements; subassemblies ofeleme
19、nts, for example, connectors, joints, ring elements; or theentire fixator.4.3 Tests of an entire assembled fixator may include thefixator alone, or alternatively, the fixator as anchored to arepresentation of the bone(s) upon which it typically would bemounted in clinical usage.5. Materials5.1 All E
20、SFDs made of materials that have an ASTMstandard shall meet those requirements given in ASTM Stan-dards listed in 2.1.6. Performance Considerations and Test Methods6.1 Individual ComponentsThe anchorage pins throughwhich an ESFD is attached to a skeletal member or memberstypically experience high fl
21、exural, or torsional loads, or both.Often, the majority of the overall compliance of an ESFD is inits anchorage elements. A test method for evaluating themechanical performance of an ESFD anchorage element ineither of these loading modes is described in Annex A5.6.2 Subassemblies of Elements:6.2.1 T
22、he sites of junction between ESFD anchorage ele-ments, for example, pins, and bridge elements, for example,rods, normally require specialized clamping or gripping mem-bers, known as connecting elements. Often, connecting ele-ments are subjected to high loads, especially moments, soadequacy of their
23、intrinsic mechanical stiffness, or strength, orboth, is critical to overall fixator performance. A test methodfor evaluating the mechanical performance of ESFD connectorelements is described in Annex A2.6.2.2 ESFDs involving ring-type bridge elements are usedwidely both for fracture treatment and fo
24、r distraction osteo-genesis. The anchorage elements in such fixators usually arewires or thin pins, which pass transverse to the bone long axisand which are tensioned deliberately to control the longitudinalstiffness of the fixator. Tensioning these wires or pins causesappreciable compressive load i
25、n the plane of the ring element.A test method for evaluating the mechanical performance ofESFD ring elements in this loading mode is described inAnnexA3.6.2.3 The high loads often developed at ESFD junction sitesare of concern both because of potentially excessive elasticdeformation and because of p
26、otential irrecoverable deforma-tion. In addition to the connecting element itself (Annex A2),overall performance of the junction also depends on theinterface between the connecting element and the anchorage,or bridge elements, or both, which it grips. A test method forevaluating the overall strength
27、, or stiffness, or both, at anexternal fixator joint, as defined inAnnexA1 as the connectingelement itself plus its interface with the anchorage, or bridge,or both, elements, which it grips, is described in Annex A4.6.2.4 The modular nature of many ESFD systems affordsthe surgeon particularly great
28、latitude as to configuration of theframe subassembly, as defined in Annex A1 as the bridgeelements plus the connecting elements used to join bridgeelements, but specifically excluding the anchorage elements.Since configuration of the frame subassembly is a majordeterminant of overall ESFD mechanical
29、 behavior, it is impor-tant to have procedures for unambiguously characterizingframe subassemblies, both geometrically and mechanically.Test methodology suitable for that purpose is described inAnnex A6.6.3 Entire Assembled FixatorNo test methods are yetapproved for entire assembled fixators.7. Keyw
30、ords7.1 anchorage element; bending; bridge element; connector;external skeletal fixation device; fracture fixation; joints;modularity; orthopedic medical device; osteosynthesis; ringelement; subassembly (frame); terminology; torsion3Withdrawn.F 1541 02 (2007)12ANNEXES(Mandatory Information)A1. CLASS
31、IFICATION OF EXTERNAL SKELETAL FIXATORSA1.1 ScopeA1.1.1 This classification covers the definitions of basicterms and considerations for external skeletal fixation devices(ESFDs) and the mechanical analyses thereof.A1.1.2 It is not the intent of this classification to definelevels of acceptable perfo
32、rmance or to make recommendationsconcerning the appropriate or preferred clinical usage of thesedevices.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 a
33、nd health practices and determine the applica-bility of regulatory limitations prior to use.A1.2 Referenced DocumentsA1.2.1 ASTM Standards:2F 366 Specification for Fixation Pins and WiresF 543 Specification and Test Methods for Metallic MedicalBone ScrewsF 544 Reference Chart for Pictorial Cortical
34、Bone ScrewClassification3A1.3 BackgroundA1.3.1 ESFDs are in widespread use in orthopedic surgery,primarily for applications involving fracture fixation or limblengthening, or both. The mechanical demands placed on thesedevices often are severe. Clinical success usually depends onsuitable mechanical
35、integration of the ESFD with the host boneor limb.A1.3.2 It is important, therefore, to have broadly acceptedterminology and testing standards by which these devices canbe described and their mechanical behaviors measured.A1.3.3 Useful terminology and testing standards must takeinto account that the
36、 modular nature of most ESFDs deliber-ately affords a great deal of clinical latitude in configuring theassembled fixator.A1.4 Significance and UseA1.4.1 The purpose of this classification is to establish aconsistent terminology system by means of which these ESFDconfigurations can be classified. It
37、 is anticipated that a com-panion testing standard using this classification system willsubsequently be developed.A1.5 Basis of ClassificationA1.5.1 An assembled ESFD and the bone(s) or bone ana-log(s) to which it is affixed constitute a fixator-bone construct.A1.5.1.1 The assembled ESFD itself, apa
38、rt from the hostbone, is termed the fixator assembly.A1.5.1.2 The individual parts (or modules of individualparts) from which the end user assembles the fixator are termedits elements.A1.5.2 An ESFD normally is configured to span a mechani-cal discontinuity in the host bone that otherwise would beun
39、able to transmit one or more components of the appliedfunctional load successfully. This bony discontinuity is termedthe mechanical defect.A1.5.3 Examples of mechanical defects are fracture sur-faces, interfragmentary callus, segmental bone gaps, articularsurfaces, neoplasms, and osteotomies.A1.5.4
40、Coordinate System(s)The relative positions of thebones or bone segments bordering the mechanical defectshould be described in terms of an orthogonal axis coordinatesystem (Fig. A1.1).A1.5.4.1 Where possible, coordinate axis directions shouldbe aligned perpendicular to standard anatomical planes, for
41、example, transverse (horizontal or axial), coronal (frontal), andsagittal (median).A1.5.4.2 Where possible, translation directions should beconsistent with standard clinical conventions, for example,ventral (anterior), dorsal (posterior), cranial (cephalad or supe-rior), caudal (inferior), lateral,
42、or medial.A1.5.4.3 Rotation measurement conventions must followthe right-hand rule and, where possible, should be consistentwith standard clinical terminology, for example, right or leftlateral bending, flexion, extension, and torsion.A1.5.5 A base coordinate system (X, Y, Z) should be affixedto one
43、 of the bones or major bone segments bordering themechanical defect. This bone or bone segment is termed thebase segment, Sb, and serves as a datum with respect to whichpertinent motion(s) of bone segments or fixator elements, orboth, can be referenced. Depending on context, Sbmay bedefined as being
44、 on either the proximal or the distal side of amechanical defect.A1.5.6 The other bone(s) or bone segment(s) bordering themechanical defect, whose potential motion(s) with respect toSbis of interest, is termed the mobile segment(s), Sm.Ifnecessary, a local right-handed orthogonal coordinate system(x
45、, y, z) may be embedded within the Sm(s).A1.5.7 Degrees of Freedom:Describing the position, or change in position, of Smrelativeto Sbrequires specifying one or more independent variables.These variables will be termed positional degrees of freedom(P-DOF).A1.5.7.1 Depending on context, this may invol
46、ve as manyas six variables (three translation and three orientation).A1.5.7.2 Also depending on context, P-DOFs may be usedto describe motions of interest in various magnitude ranges.For example, P-DOFs may be used to describe one or moreF 1541 02 (2007)13components of visually imperceptible motion,
47、 for example,elastic flexure of a thick rod) or one or more components ofgrossly evident motion, such as, interfragmentary motion at anunstable fracture site.A1.5.8 Application or adjustment of an ESFD normallyincludes an attempt to achieve or maintain a specific position ofSmrelative to Sb. The adj
48、ustability afforded by the ESFDdesign for this purpose, most commonly, fracture fragmentreduction, will be characterized in terms of adjustment degreesof freedom (A-DOF).A1.5.9 Some ESFDs are designed optionally to transmitselected components of loading or displacement across thedefect, usually by d
49、isengaging a locking mechanism. Thecomponent of motion of Smpermitted by such unlocking, oftengiven the clinical name “dynamization,” will be termed un-locked degrees of freedom (U-DOF).A1.5.9.1 Depending on the specifics of design, the motionpermitted in an unlocked degree of freedom may be opposedsubstantially and deliberately by a specific mechanism such asa spring or a cushion. Such an unlocked degree of freedom istermed a resisted unlocked degree of freedom.A1.5.9.2 Unlocked degrees of freedom in which motion isinduced actively by external energy input from
