ASTM F1541-02(2011)e1

Standard Specification and Test Methods for External Skeletal Fixation Devices

SIGNIFICANCE AND USE
A1.4.1 The purpose of this classification is to establish a consistent terminology system by means of which these ESFD configurations can be classified. It is anticipated that a companion testing standard using this classification system will subsequently be developed.
SCOPE
1.1 This specification provides a characterization of the design and mechanical function of external skeletal fixation devices (ESFDs), test methods for characterization of ESFD mechanical properties, and identifies needs for further development of test methods and performance criteria. The ultimate goal is to develop a specification, which defines performance criteria and methods for measurement of performance-related mechanical characteristics of ESFDs and their fixation to bone. It is not the intention of this specification to define levels of performance or case-specific clinical performance of the devices, as insufficient knowledge is available to predict the consequences of the use of any of these devices in individual patients for specific activities of daily living. Furthermore, it is not the intention of this specification to describe or specify specific designs for ESFDs.
1.2 This specification describes ESFDs for surgical fixation of the skeletal system. It provides basic ESFD geometrical definitions, dimensions, classification, and terminology; material specifications; performance definitions; test methods; and characteristics determined to be important to the in-vivo performance of the device.
1.3 This specification includes a terminology and classification annex and five standard test method annexes as follows:
1.3.1 Classification of External Fixators—Annex A1.
1.3.2 Test Method for External Skeletal Fixator Connectors—Annex A2.
1.3.3 Test Method for Determining In-Plane Compressive Properties of Circular Ring or Ring Segment Bridge Elements—Annex A3.
1.3.4 Test Method for External Skeletal Fixator Joints—Annex A4.
1.3.5 Test Method for External Skeletal Fixator Pin Anchorage Elements—Annex A5.
1.3.6 Test Method for External Skeletal Fixator Subassemblies—Annex A6.
1.3.7 Test Method for External Skeletal Fixator/Constructs Subassemblies—Annex A7.
1.4 A rationale is given in Appendix X1.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.6 The following safety hazards caveat pertains only to the test method portions (Annex A2-Annex A6):
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 30-Sep-2011
• ICS: 11.120.20 - Wound dressings and compresses
• Technical Committee: F04 - Medical and Surgical Materials and Devices
• Drafting Committee: F04.21 - Osteosynthesis

Relations

• Replaces: ASTM F1541-02(2011) - Standard Specification and Test Methods for External Skeletal Fixation Devices
• Effective Date: 01-Oct-2011
• Replaced By: ASTM F1541-02(2015) - Standard Specification and Test Methods for External Skeletal Fixation Devices
• Effective Date: 01-Sep-2015

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
´1
Designation:F1541 −02(Reapproved 2011)
Standard Specification and Test Methods for
External Skeletal Fixation Devices
This standard is issued under the fixed designation F1541; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
ε NOTE—Editorial changes were made throughout in July 2012.
1. Scope 1.3.6 Test Method for External Skeletal Fixator
Subassemblies—Annex A6.
1.1 This specification provides a characterization of the
1.3.7 Test Method for External Skeletal Fixator/Constructs
design and mechanical function of external skeletal fixation
Subassemblies—Annex A7.
devices (ESFDs), test methods for characterization of ESFD
mechanical properties, and identifies needs for further devel- 1.4 A rationale is given in Appendix X1.
opment of test methods and performance criteria.The ultimate
1.5 The values stated in SI units are to be regarded as
goal is to develop a specification, which defines performance
standard. No other units of measurement are included in this
criteria and methods for measurement of performance-related
standard.
mechanicalcharacteristicsofESFDsandtheirfixationtobone.
1.6 The following safety hazards caveat pertains only to the
It is not the intention of this specification to define levels of
test method portions (Annex A2 – Annex A6):
performance or case-specific clinical performance of the
1.7 This standard does not purport to address all of the
devices, as insufficient knowledge is available to predict the
safety concerns, if any, associated with its use. It is the
consequences of the use of any of these devices in individual
patients for specific activities of daily living. Furthermore, it is responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
not the intention of this specification to describe or specify
specific designs for ESFDs. bility of regulatory limitations prior to use.
1.2 This specification describes ESFDs for surgical fixation
2. Referenced Documents
of the skeletal system. It provides basic ESFD geometrical
2.1 ASTM Standards:
definitions, dimensions, classification, and terminology; mate-
A938Test Method for Torsion Testing of Wire
rial specifications; performance definitions; test methods; and
D790Test Methods for Flexural Properties of Unreinforced
characteristics determined to be important to the in-vivo
and Reinforced Plastics and Electrical Insulating Materi-
performance of the device.
als
1.3 This specification includes a terminology and classifi-
E4Practices for Force Verification of Testing Machines
cationannexandfivestandardtestmethodannexesasfollows:
F67Specification for Unalloyed Titanium, for Surgical Im-
1.3.1 Classification of External Fixators—Annex A1.
plant Applications (UNS R50250, UNS R50400, UNS
1.3.2 Test Method for External Skeletal Fixator
R50550, UNS R50700)
Connectors—Annex A2.
F90 Specification for Wrought Cobalt-20Chromium-
1.3.3 Test Method for Determining In-Plane Compressive
15Tungsten-10NickelAlloy for Surgical ImplantApplica-
Properties of Circular Ring or Ring Segment Bridge
tions (UNS R30605)
Elements—Annex A3.
F136 Specification for Wrought Titanium-6Aluminum-
1.3.4 Test Method for External Skeletal Fixator Joints—
4VanadiumELI(ExtraLowInterstitial)AlloyforSurgical
Annex A4.
Implant Applications (UNS R56401)
1.3.5 Test Method for External Skeletal Fixator Pin Anchor-
F138 Specification for Wrought 18Chromium-14Nickel-
age Elements—Annex A5.
2.5MolybdenumStainlessSteelBarandWireforSurgical
Implants (UNS S31673)
F366Specification for Fixation Pins and Wires
This specification is under the jurisdiction of ASTM Committee F04 on
Medical and Surgical Materials and Devices and is the direct responsibility of
Subcommittee F04.21 on Osteosynthesis. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Oct. 1, 2011. Published October 2011. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
published as F1541–94. Last previous edition approved in 2007 as F1541–02 Standards volume information, refer to the standard’s Document Summary page on
ε1
(2007) . DOI: 10.1520/F1541-02R11E01. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
´1
F1541−02 (2011)
F543Specification and Test Methods for Metallic Medical 6.2 Subassemblies of Elements:
Bone Screws 6.2.1 The sites of junction between ESFD anchorage ele-
F544Reference Chart for Pictorial Cortical Bone Screw ments (for example, pins) and bridge elements (for example,
Classification (Withdrawn 1998) rods) normally require specialized clamping or gripping
F1058Specification for Wrought 40Cobalt-20Chromium- members, known as connecting elements. Often, connecting
16Iron-15Nickel-7Molybdenum Alloy Wire and Strip for elements are subjected to high loads, especially moments, so
Surgical Implant Applications (UNS R30003 and UNS adequacy of their intrinsic mechanical stiffness, or strength, or
R30008) both, is critical to overall fixator performance. A test method
F1264Specification and Test Methods for Intramedullary forevaluatingthemechanicalperformanceofESFDconnector
Fixation Devices elements is described in Annex A2.
F1472 Specification for Wrought Titanium-6Aluminum- 6.2.2 ESFDs involving ring-type bridge elements are used
4VanadiumAlloyforSurgicalImplantApplications(UNS widely both for fracture treatment and for distraction osteo-
R56400) genesis. The anchorage elements in such fixators usually are
F1713 Specification for Wrought Titanium-13Niobium- wires or thin pins, which pass transverse to the bone long axis
13Zirconium Alloy for Surgical Implant Applications andwhicharetensioneddeliberatelytocontrolthelongitudinal
(UNS R58130) stiffness of the fixator. Tensioning these wires or pins causes
appreciable compressive load in the plane of the ring element.
3. Terminology
A test method for evaluating the mechanical performance of
ESFDringelementsinthisloadingmodeisdescribedinAnnex
3.1 Definitions—Thedefinitionsoftermsrelatingtoexternal
A3.
fixators are described in Annex A1.
6.2.3 ThehighloadsoftendevelopedatESFDjunctionsites
4. Classification
are of concern both because of potentially excessive elastic
deformation and because of potential irrecoverable deforma-
4.1 Externalskeletalfixatorsaremodulardevicesassembled
tion. In addition to the connecting element itself (Annex A2),
from component elements.
overall performance of the junction also depends on the
4.2 Test methods can address individual elements (for
interface between the connecting element and the anchorage,
example,anchorageelements,bridgeelements);subassemblies
or bridge elements, or both, which it grips. A test method for
ofelements(forexample,connectors,joints,ringelements);or
evaluating the overall strength, or stiffness, or both, at an
the entire fixator.
externalfixatorjoint,asdefinedinAnnexA1astheconnecting
4.3 Tests of an entire assembled fixator may include the
element itself plus its interface with the anchorage, or bridge,
fixator alone, or alternatively, the fixator as anchored to a
or both, elements, which it grips, is described in Annex A4.
representation of the bone(s) upon which it typically would be
6.2.4 The modular nature of many ESFD systems affords
mounted in clinical usage.
thesurgeonparticularlygreatlatitudeastoconfigurationofthe
frame subassembly, as defined in Annex A1 as the bridge
5. Materials
elements plus the connecting elements used to join bridge
5.1 All ESFDs made of materials that have an ASTM elements, but specifically excluding the anchorage elements.
standard shall meet those requirements given in ASTM Stan- Since the configuration of the frame subassembly is a major
dards listed in 2.1. determinant of overall ESFD mechanical behavior, it is impor-
tant to have procedures for unambiguously characterizing
6. Performance Considerations and Test Methods
frame subassemblies, both geometrically and mechanically.
Test methodology suitable for that purpose is described in
6.1 Individual Components—The anchorage pins by which
Annex A6.
anESFDisattachedtoaskeletalmemberormemberstypically
experience high flexural, or torsional loads, or both. Often, the
6.3 Entire Assembled Fixator—No test methods are yet
majority of the overall compliance of an ESFD is in its
approved for entire assembled fixators.
anchorageelements.Atestmethodforevaluatingthemechani-
7. Keywords
cal performance of an ESFD anchorage element in either of
these loading modes is described in Annex A5.
7.1 anchorageelement;bending;bridgeelement;connector;
external skeletal fixation device; fracture fixation; joints;
3 modularity; orthopedic medical device; osteosynthesis; ring
The last approved version of this historical standard is referenced on
www.astm.org. element; subassembly (frame); terminology; torsion
´1
F1541−02 (2011)
ANNEXES
(Mandatory Information)
A1. CLASSIFICATION OF EXTERNAL SKELETAL FIXATORS
A1.1. Scope A1.5.1.2 The individual parts (or modules of individual
parts)fromwhichtheenduserassemblesthefixatoraretermed
A1.1.1 This classification covers the definitions of basic
its elements.
terms and considerations for external skeletal fixation devices
(ESFDs) and the mechanical analyses thereof. A1.5.2 AnESFDnormallyisconfiguredtospanamechani-
cal discontinuity in the host bone that otherwise would be
A1.1.2 It is not the intent of this classification to define
unable to transmit one or more components of the applied
levels of acceptable performance or to make recommendations
functional load successfully.This bony discontinuity is termed
concerning the appropriate or preferred clinical usage of these
the mechanical defect.
devices.
A1.5.3 Examples of mechanical defects are fracture
A1.1.3 This standard does not purport to address all of the
surfaces, interfragmentary callus, segmental bone gaps, articu-
safety concerns, if any, associated with its use. It is the
lar surfaces, neoplasms, and osteotomies.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
A1.5.4 Coordinate System(s)—The relative positions of the
bility of regulatory limitations prior to use.
bones or bone segments bordering the mechanical defect
should be described in terms of an orthogonal axis coordinate
A1.2. Referenced Documents system (Fig. A1.1).
2 A1.5.4.1 Where possible, coordinate axis directions should
A1.2.1 ASTM Standards:
be aligned perpendicular to standard anatomical planes (for
F366Specification for Fixation Pins and Wires
example,transverse(horizontaloraxial),coronal(frontal),and
F543Specification and Test Methods for Metallic Medical
sagittal (median)).
Bone Screws
A1.5.4.2 Where possible, translation directions should be
F544Reference Chart for Pictorial Cortical Bone Screw
consistent with standard clinical conventions (for example,
Classification (Withdrawn 1998)
ventral (anterior), dorsal (posterior), cranial (cephalad or
superior), caudal (inferior), lateral, or medial).
A1.3 Background
A1.5.4.3 Rotation measurement conventions must follow
A1.3.1 ESFDs are in widespread use in orthopedic surgery,
the right-hand rule and, where possible, should be consistent
primarily for applications involving fracture fixation or limb
with standard clinical terminology (for example, right or left
lengthening,orboth.Themechanicaldemandsplacedonthese
lateral bending, flexion, extension, and torsion).
devices often are severe. Clinical success usually depends on
A1.5.5 Abase coordinate system (X, Y, Z) should be affixed
suitablemechanicalintegrationoftheESFDwiththehostbone
to one of the bones or major bone segments bordering the
or limb.
mechanical defect. This bone or bone segment is termed the
A1.3.2 It is important, therefore, to have broadly accepted
base segment, S , and serves as a datum with respect to which
b
terminology and testing standards by which these devices can
pertinent motion(s) of bone segments or fixator elements, or
be described and their mechanical behaviors measured.
both, can be referenced. Depending on context, S may be
b
A1.3.3 Useful terminology and testing standards must take defined as being on either the proximal or the distal side of a
into account that the modular nature of most ESFDs deliber- mechanical defect.
ately affords a great deal of clinical latitude in configuring the
A1.5.6 The other bone(s) or bone segment(s) bordering the
assembled fixator.
mechanical defect, whose potential motion(s) with respect to
S is of interest, is termed the mobile segment(s), S.If
b m
A1.4. Significance and Use
necessary, a local right-handed orthogonal coordinate system
A1.4.1 The purpose of this classification is to establish a (x, y, z) may be embedded within the S (s).
m
consistent terminology system by means of which these ESFD
A1.5.7 Degrees of Freedom: Describing the position, or
configurations can be classified. It is anticipated that a com-
change in position, of S relative to S requires specifying one
m b
panion testing standard using this classification system will
ormoreindependentvariables.Thesevariablesshallbetermed
subsequently be developed.
positional degrees of freedom (P-DOF).
A1.5.7.1 Depending on context, this may involve as many
A1.5 Basis of Classification
as six variables (three translation and three orientation).
A1.5.1 An assembled ESFD and the bone(s) or bone ana-
A1.5.7.2 Also depending on context, P-DOFs may be used
log(s) to which it is affixed constitute a fixator-bone construct.
to describe motions of interest in various magnitude ranges.
A1.5.1.1 The assembled ESFD itself, apart from the host For example, P-DOFs may be used to describe one or more
bone, is termed the fixator assembly. components of visually imperceptible motion (for example,
´1
F1541−02 (2011)
a spring or a cushion. Such an unlocked degree of freedom is
termed a resisted unlocked degree of freedom.
A1.5.9.2 Unlocked degrees of freedom in which motion is
induced actively by external energy input from devices asso-
ciatedwiththefixatoraretermed actuateddegreesoffreedom.
A1.5.9.3 Anunlockeddegreeoffreedominwhichmotionis
unopposed by a specific design mechanism is termed an
unresisted unlocked degree of freedom. Incidental friction in a
dynamizing element shall not be construed as representing
deliberately resisted motion; however, conditions involving
untoward resistance to motion, for example, substantial bind-
ing friction, in a supposedly unresiste
...