ASTM F2009-00(2005)
(Test Method)Standard Test Method for Determining the Axial Disassembly Force of Taper Connections of Modular Prostheses
Standard Test Method for Determining the Axial Disassembly Force of Taper Connections of Modular Prostheses
SIGNIFICANCE AND USE
This test method helps to assess the axial locking force of a modular taper. Examples of these devices are described in Specification F 1636. Some types of devices that may utilize this type of connection are the modular shoulder and modular hip prostheses. Additional means of evaluating the locking mechanisms of tapers may be appropriate, depending upon the design of the device.
This test method may not be appropriate for all implant applications. The user is cautioned to consider the appropriateness of the practice in view of the materials and design being tested and their potential application.
While this practice may be used to measure the force required to disengage tapers, any comparison of such data for various component designs must take into consideration the size of the implant and the type of locking mechanism evaluated.
SCOPE
1.1 This test method establishes a standard methodology for determining the force required, under laboratory conditions, to disassemble tapers of implants that are otherwise not intended to release. Some examples are the femoral components of a total or partial hip replacement or shoulder in which the head and base component are secured together by a self-locking taper.
1.2 This test method has been developed primarily for evaluation of metal and ceramic head designs on metal tapers but may have application to other materials and designs.
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.
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Designation:F2009–00 (Reapproved 2005)
Standard Test Method for
Determining the Axial Disassembly Force of Taper
Connections of Modular Prostheses
This standard is issued under the fixed designation F2009; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3. Summary of Test Method
1.1 This test method establishes a standard methodology for 3.1 The axial disassembly test method provides a means to
determining the force required, under laboratory conditions, to measure the axial locking strength of the taper connection for
disassemble tapers of implants that are otherwise not intended modular prostheses.
to release. Some examples are the femoral components of a 3.2 Following assembly, an axial tensile force is applied to
total or partial hip replacement or shoulder in which the head disassemble the taper connection and the maximum force is
and base component are secured together by a self-locking recorded.
taper.
4. Significance and Use
1.2 This test method has been developed primarily for
evaluation of metal and ceramic head designs on metal tapers 4.1 This test method helps to assess the axial locking force
of a modular taper. Examples of these devices are described in
but may have application to other materials and designs.
1.3 This standard does not purport to address all of the Specification F1636. Some types of devices that may utilize
this type of connection are the modular shoulder and modular
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- hip prostheses. Additional means of evaluating the locking
mechanisms of tapers may be appropriate, depending upon the
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. design of the device.
4.2 This test method may not be appropriate for all implant
2. Referenced Documents
applications. The user is cautioned to consider the appropriate-
2.1 ASTM Standards: ness of the practice in view of the materials and design being
E4 Practices for Force Verification of Testing Machines tested and their potential application.
F1636 Specification for Bores and Cones for Modular 4.3 While this practice may be used to measure the force
Femoral Heads required to disengage tapers, any comparison of such data for
various component designs must take into consideration the
size of the implant and the type of locking mechanism
evaluated.
This test method is under the jurisdiction ofASTM Committee F04 on Medical
and Surgical Materials and Devices and is the direct responsibility of Subcommittee
5. Apparatus
F04.22 on Arthroplasty.
Current edition approved Oct. 1, 2005. Published October 2005. Originally
5.1 The cone portion of the assembly shall be constrained
approved in 2000. Last previous edition approved in 2000 as F2009 – 00. DOI:
by suitable fixtures that can sustain high loads.
10.1520/F2009-00R05.
2 5.2 The fixtures shall be constructed so that the line of load
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
application is aligned with the axes of the male and female
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
taper components within 61°.
the ASTM website.
5.2.1 For example, modular heads may be assembled by a
Withdrawn.
solid metal 100° cone as shown in Fig. 1. The cone should
Withdrawn. The last approved version of this historical standard is referenced
on www.astm.org. provide line contact around the diameter of the head.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
F2009–00 (2005)
5.3 The testing machine shall conform to the requirements
of Practices E4. The loads used to determine the attachment
strength shall be within the range of the testing machine as
defined in Practices E4.
5.4 The test machine should be capable of delivering a
compressive and tensile force at a constant displacement rate.
The test machine should have a load monitoring and recording
system.
6. Sampling and Test Specimens
6.1 The male and female taper components can be finished
implants or they can be simplified test specimens. The test
specimens must have tapers manufactured to the specifications
of a finished implant including material and preferably manu-
factured with the same equipment.
6.2 Thesupportingmaterialaroundthefemaletapermustbe
similar in size and shape to the finished implant.
6.3 A minimum of five taper assemblies shall be tested to
determine the axial disassembly force between the tapered
components. Pairing of the components shall be random unless
otherwise reported. The appropriateness of performing mul-
tiple tests on the same taper connection will depend on the
design and application of the device.
6.4 Sterilization of test components is not required unless it
has known effects on the parts being evaluated. Generally,
sterilization does not have an effect on metallic materials.
FIG. 1 Modular Head Assembly
7. Procedure
7.1 Following normal laboratory cleaning procedures to
5.2.2 For example, modular heads may be disassembled
remove any debris or other surface contaminants, the taper
with a metal cage that surrounds the head and provides even
components are assembled on a suitable test machine. A
contact around the inferior edge of the head as shown in Fig. 2.
suggested procedure for cleaning and drying of the specimens
is given in Appendix X1.
7.2 Each specimen should be characterized prior to testing.
This information may include, but is not limited to the
following: material, hardness, bore and taper diameters, con-
centricity, surface roughness, taper angle, and length of en-
gagement.
7.3 Taperscanbeassembledusingtwomethods.Depending
ontheintendeduse,theusermayusetheassemblymethodthat
best suits the taper application.
7.3.1 Constant Rate Assembly Meth
...
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