1、Designation: F1541 17Standard 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 year of last revision
2、. 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 fixationdevices (ESFDs), t
3、est 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-relatedmechanical charac
4、teristics 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 thedevices, as insufficient knowledge is available to predict theconsequences of the use of any of these devices in individualpatients f
5、or 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, dimensions, classifica
6、tion, 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 annexes as follows:1.3.1
7、 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 JointsAnnex A4.1.3.5
8、 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 stated in SI units ar
9、e to be regarded asstandard. No other units of measurement are included in thisstandard.1.6 Multiple test methods are included in this standard.However, the user is not necessarily obligated to test using allof the described methods. Instead, the user should only select,with justification, test meth
10、ods that are appropriate for aparticular device design. This may be only a subset of theherein described test methods1.7 The following safety hazards caveat pertains only to thetest method portions (Annex A2 Annex A6):1.8 This standard does not purport to address all of thesafety concerns, if any, a
11、ssociated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.9 This international standard was developed in accor-dance with internationally
12、 recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2A938 Test Metho
13、d for Torsion Testing of WireD790 Test Methods for Flexural Properties of Unreinforcedand Reinforced Plastics and Electrical Insulating Materi-alsE4 Practices for Force Verification of Testing MachinesF366 Specification for Fixation Pins and WiresF543 Specification and Test Methods for Metallic Medi
14、calBone ScrewsF544 Reference Chart for Pictorial Cortical Bone Screw1This 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, 2017. Publis
15、hed September 2017. Originallypublished as F1541 94. Last previous edition approved in 2015 asF1541 02 (2015). DOI: 10.1520/F1541-17.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume infor
16、mation, refer to the standards Document Summary page onthe ASTM website.This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommenda
17、tions issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1Classification (Withdrawn 1998)3F1264 Specification and Test Methods for IntramedullaryFixation DevicesF2503 Practice for Marking Medical Devices and OtherItems for Safety in the Magnetic Resonance Environment3
18、. Terminology3.1 DefinitionsThe definitions of terms relating to externalfixators 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 (forexample, anchorage elements, bridge el
19、ements); subassembliesof elements (for example, connectors, joints, ring elements); orthe entire 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 clini
20、cal usage.5. Materials5.1 ESFDs construction materials should be chosen basedon the design requirements of the particular device. ASTMcommittee F04 on Medical and Surgical Materials and Devicesmaintains a number of material specifications suitable forsurgical implant and instrument applications.6. P
21、erformance Considerations and Test Methods6.1 Individual ComponentsThe anchorage pins by whichan ESFD is attached to a skeletal member or members typicallyexperience high flexural, or torsional loads, or both. Often, themajority of the overall compliance of an ESFD is in itsanchorage elements.Atest
22、method for evaluating the mechani-cal performance of an ESFD anchorage element in either ofthese loading modes is described in Annex A5.6.2 Subassemblies of Elements:6.2.1 The sites of junction between ESFD anchorage ele-ments (for example, pins) and bridge elements (for example,rods) normally requi
23、re specialized clamping or grippingmembers, known as connecting elements. Often, connectingelements are subjected to high loads, especially moments, soadequacy of their intrinsic mechanical stiffness, or strength, orboth, is critical to overall fixator performance. A test methodfor evaluating the me
24、chanical 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 elements in such fixators usually arewires or thin pins, which pass transverse to the bo
25、ne 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 for evaluating the mechanical performance ofESFD ring elements in this loading mode i
26、s described in AnnexA3.6.2.3 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 addition to the connecting element itself (Annex A2),overall performance of the junction a
27、lso 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 fixator joint, as defined in AnnexA1 as the connectingelement itself plus its interface wit
28、h 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 subassembly, as defined in Annex A1 as the bridgeelements plus the connecting elements u
29、sed to join bridgeelements, but specifically excluding the anchorage elements.Since the configuration of the frame subassembly is a majordeterminant of overall ESFD mechanical behavior, it is impor-tant to have procedures for unambiguously characterizingframe subassemblies, both geometrically and me
30、chanically.Test methodology suitable for that purpose is described inAnnex A6.6.3 Entire Assembled FixatorNo test methods are yetapproved for entire assembled fixators.7. Handling7.1 Consider Practice F2503 to identify potential hazardsproduced by interactions between the device and the MRenvironmen
31、t and for terms that may be used to label the devicefor safety in the MR environment.8. Keywords8.1 anchorage element; bending; bridge element; connector;external skeletal fixation device; fracture fixation; joints;modularity; orthopedic medical device; osteosynthesis; ringelement; subassembly (fram
32、e); terminology; torsion3The last approved version of this historical standard is referenced onwww.astm.org.F1541 172ANNEXES(Mandatory Information)A1. CLASSIFICATION OF EXTERNAL SKELETAL FIXATORSA1.1. ScopeA1.1.1 This classification covers the definitions of basicterms and considerations for externa
33、l skeletal fixation devices(ESFDs) and the mechanical analyses thereof.A1.1.2 It is not the intent of this classification 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 t
34、o 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, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.A1.1.4 This international standard
35、was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.A1.2. Ref
36、erenced DocumentsA1.2.1 ASTM Standards:2F366 Specification for Fixation Pins and WiresF543 Specification and Test Methods for Metallic MedicalBone ScrewsF544 Reference Chart for Pictorial Cortical Bone ScrewClassification (Withdrawn 1998)3A1.3 BackgroundA1.3.1 ESFDs are in widespread use in orthoped
37、ic 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 integration of the ESFD with the host boneor limb.A1.3.2 It is important, therefore, t
38、o 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 modular nature of most ESFDs deliber-ately affords a great deal of clinical latitude
39、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 is anticipated that a com-panion testing standard using this classification system w
40、illsubsequently 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, apart from the hostbone, is termed the fixator assembly.A1.5.1.2 The individual parts (o
41、r 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 beunable to transmit one or more components of the appliedfunctional load successfully. T
42、his bony discontinuity is termedthe mechanical defect.A1.5.3 Examples of mechanical defects are fracturesurfaces, interfragmentary callus, segmental bone gaps, articu-lar surfaces, neoplasms, and osteotomies.A1.5.4 Coordinate System(s)The relative positions of thebones or bone segments bordering the
43、 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 (forexample, transverse (horizontal or axial), coronal (frontal), andsagittal (median).A1
44、.5.4.2 Where possible, translation directions should beconsistent with standard clinical conventions (for example,ventral (anterior), dorsal (posterior), cranial (cephalad orsuperior), caudal (inferior), lateral, or medial).A1.5.4.3 Rotation measurement conventions must followthe right-hand rule and
45、, 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 of the bones or major bone segments bordering themechanical defect. This bone or bon
46、e 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 on either the proximal or the distal side of amechanical defect.A1.5.6 The other bon
47、e(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, y, z) may be embedded within the Sm(s).A1.5.7 Degrees of Freedom: Describing the po
48、sition, orchange in position, of Smrelative to Sbrequires specifying oneor more independent variables. These variables shall be termedpositional degrees of freedom (P-DOF).F1541 173A1.5.7.1 Depending on context, this may involve as manyas six variables (three translation and three orientation).A1.5.
49、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 morecomponents of 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 position ofSmrelative to Sb. The adjustability afforded by the ESFDdesign for this purpose, most com
