1、Designation: F1541 02 (Reapproved 2011)Standard Specification and Test Methods forExternal Skeletal Fixation Devices1This standard is issued under the fixed designation F1541; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the yea
2、r 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 specification provides a characterization of thedesign and mechanical function of external skeletal fixation
3、devices (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 performancecriteria and methods for measurement of performance-relate
4、dmechanical 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 available to predict theconsequences of the use of any of these devices in
5、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 skeletal system. It provides basic ESFD geometricaldefinitions, di
6、mensions, 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 terminology and classifi-cation annex and five standard test method anne
7、xes 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 BridgeElementsAnnex A3.1.3.4 Test Method for External Skeletal Fixator
8、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/ConstructsSubassembliesAnnex A7.1.4 A rationale is given in Appendix X1.1.5 The values s
9、tated 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 not purport to address all of thesafety concerns, if any, associated
10、 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 Standards:2A938 Test Method for Torsion Testing of WireD790 Test Methods f
11、or 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 R50250, UNS R50400, UNSR50550, UNS R50700)F90 Specification for Wrou
12、ght Cobalt-20Chromium-15Tungsten-10Nickel Alloy for Surgical Implant Applica-tions (UNS R30605)F136 Specification for Wrought Titanium-6Aluminum-4Vanadium ELI (Extra Low Interstitial) Alloy for SurgicalImplant Applications (UNS R56401)F138 Specification for Wrought 18Chromium-14Nickel-2.5Molybdenum
13、Stainless Steel Bar and Wire for SurgicalImplants (UNS S31673)F366 Specification for Fixation Pins and WiresF543 Specification and Test Methods for Metallic MedicalBone Screws1This specification is under the jurisdiction of ASTM Committee F04 onMedical and Surgical Materials and Devices and is the d
14、irect responsibility ofSubcommittee F04.21 on Osteosynthesis.Current edition approved Oct. 1, 2011. Published October 2011. Originallypublished as F1541 94. Last previous edition approved in 2007 as F1541 02(2007)1. DOI: 10.1520/F1541-02R11.2For referenced ASTM standards, visit the ASTM website, www
15、.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 Conshohocken, PA 19428-2959, United States.F544
16、Reference Chart for Pictorial Cortical Bone ScrewClassification3F1058 Specification for Wrought 40Cobalt-20Chromium-16Iron-15Nickel-7Molybdenum Alloy Wire and Strip forSurgical Implant Applications (UNS R30003 and UNSR30008)F1264 Specification and Test Methods for IntramedullaryFixation DevicesF1472
17、 Specification for Wrought Titanium-6Aluminum-4Vanadium Alloy for Surgical Implant Applications (UNSR56400)F1713 Specification for Wrought Titanium-13Niobium-13Zirconium Alloy for Surgical Implant Applications(UNS R58130)3. Terminology3.1 DefinitionsThe definitions of terms relating to exter-nal fix
18、ators 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 ofelements, for example, connectors, joints, ring el
19、ements; 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 ESFDs made of materials that have an ASTMstand
20、ard 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 flexural, or torsional loads, or both.Often, th
21、e 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 The sites of junction between ESFD anchorage e
22、le-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 intrinsic mechanical stiffness, or strength,
23、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 for distraction osteo-genesis. The anchorage el
24、ements 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 in the plane of the ring element.A test method
25、 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 potential irrecoverable deforma-tion. In addit
26、ion 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, or stiffness, or both, at anexternal fixato
27、r 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 latitude as to configuration of theframe suba
28、ssembly, 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 behavior, it is impor-tant to have procedure
29、s 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. Keywords7.1 anchorage element; bending; bridge el
30、ement; connector;external skeletal fixation device; fracture fixation; joints;modularity; orthopedic medical device; osteosynthesis; ringelement; subassembly (frame); terminology; torsion3Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.F1541 02 (2011)2AN
31、NEXES(Mandatory Information)A1. CLASSIFICATION 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 classificatio
32、n to definelevels of acceptable performance 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 standa
33、rd to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.A1.2 Referenced DocumentsA1.2.1 ASTM Standards:2F366 Specification for Fixation Pins and WiresF543 Specification and Test Methods for Metallic MedicalBone ScrewsF544 Refer
34、ence Chart for Pictorial Cortical 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 usua
35、lly depends onsuitable mechanical 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 standa
36、rds must takeinto account that the 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 ESFDco
37、nfigurations can be classified. It 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.
38、1.1 The assembled ESFD itself, apart 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 h
39、ost bone that otherwise would beunable 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,
40、neoplasms, and osteotomies.A1.5.4 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
41、to standard anatomical planes, forexample, 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-r
42、ior), caudal (inferior), lateral, 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
43、 (X, Y, Z) should be affixedto one 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
44、 context, Sbmay bedefined as being 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-han
45、ded orthogonal coordinate system(x, 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 De
46、pending on context, this may involve 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 moreF1541 02 (2011)3components o
47、f visually imperceptible motion, 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 posi
48、tion ofSmrelative to Sb. The adjustability 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 displacemen
49、t across thedefect, usually by disengaging 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
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