ASTM F1440-92(1997)

Standard Practice for Cyclic Fatigue Testing of Metallic Stemmed Hip Arthroplasty Femoral Components Without Torsion

SCOPE
1.1 This practice describes a method for the fatigue testing of metallic stemmed femoral components used in hip arthroplasty. The described method is intended to be used to evaluate the comparison of various designs and materials used for stemmed femoral components used in the arthroplasty. This practice covers procedures for the performance of fatigue tests using (as a forcing function) a periodic constant amplitude force.
1.2 This practice applies primarily to one-piece prostheses and modular components, with head in place such that prostheses should not have an anterior/posterior bow, and should have a nearly straight section on the distal 50 mm of the stem. This practice may require modifications to accommodate other femoral stem designs.
1.3 For additional information see Refs. (1) through (5).

General Information

• Status: Historical
• Publication Date: 09-Jul-1997
• Technical Committee: F04 - Medical and Surgical Materials and Devices
• Drafting Committee: F04.22 - Arthroplasty

Relations

• Replaced By: ASTM F1440-92(2002) - Standard Practice for Cyclic Fatigue Testing of Metallic Stemmed Hip Arthroplasty Femoral Components Without Torsion
• Effective Date: 15-Sep-1992
• Referred By: ASTM F1875-98(2022) - Standard Practice for Fretting Corrosion Testing of Modular Implant Interfaces: Hip Femoral Head-Bore and Cone Taper Interface
• Effective Date: 10-Jul-1997

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: F 1440 – 92 (Reapproved 1997)
Standard Practice for
Cyclic Fatigue Testing of Metallic Stemmed Hip Arthroplasty
Femoral Components Without Torsion
This standard is issued under the fixed designation F 1440; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This practice describes a method for the fatigue testing
of metallic stemmed femoral components used in hip arthro-
plasty. The described method is intended to be used to evaluate
the comparison of various designs and materials used for
stemmed femoral components used in the arthroplasty. This
practice covers procedures for the performance of fatigue tests
using (as a forcing function) a periodic constant amplitude
force.
1.2 This practice applies primarily to one-piece prostheses
and modular components, with head in place such that pros-
theses should not have an anterior/posterior bow, and should
have a nearly straight section on the distal 50 mm of the stem.
This practice may require modifications to accommodate other
femoral stem designs.
1.3 For additional information see Refs. (1-5) .
2. Referenced Documents
2.1 ASTM Standards:
E 4 Practices for Load Verification of Testing Machines
E 466 Recommended Practice for Constant Amplitude
Axial Fatigue Tests for Metallic Materials
E 467 Practice for Verification of Constant Amplitude Dy-
namic Loads in an Axial Load Fatigue Testing Machine
E 468 Recommended Practice for the Presentation of Con-
FIG. 1 Collared Device
stant Amplitude Fatigue Test Results for Metallic Materi-
als
are the mean values of the coordinates of all the points in the
area.
3. Terminology
3.1.5 line of load application—the loading axis of the test
3.1 Definitions and Symbols (see Fig. 1(a) and 1(b)):
machine.
3.1.1 cantilever plane—a plane perpendicular to the line of
3.1.6 Reference Line L1, distal stem axis—the medial-
load application at the level on the stem where the stem
lateral (M-L) centerline of the most distal 50 mm of stem in the
becomes unsupported.
A-P projection.
3.1.2 distal stem axis—the centerline in the anterior/
3.1.7 Reference Line L2:
posterior projection of the most distal 50 mm of the stem.
3.1.7.1 collared device— the plane of the distal side of the
3.1.3 estimated maximum bending moment—the maximum
collar in the A-P projection.
load times the unloaded moment arm.
3.1.7.2 collarless device—the resection plane recommended
3.1.4 geometric centroid (cantilever plane)— the point in a
for the device in the A-P projection.
cross-sectional area of the cantilever plane whose coordinates
3.1.8 Reference Point P1—the spherical center of the pros-
thesis head.
This practice is under the jurisdiction of ASTM Committee F-4 on Medical and
3.1.9 Reference Point P3:
Surgical Materials and Devices and is the direct responsibility of Subcommittee
3.1.9.1 collared device— the intersection of the principal
F04.22 on Arthroplasty.
axis of the collar (L2) with the medial surface of the stem in the
Current edition approved Sept. 15, 1992. Published November 1992.
Annual Book of ASTM Standards, Vol 03.01. A-P projection.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
F 1440
3.1.9.2 collarless device—the intersection of the resection to cyclic loading for relatively large numbers of cycles. The
plane (L2) with the medial surface of the stem in the A-P recommended test assumes a “worst case” situation where
projection. proximal support for the stem has been lost. It is also
3.1.10 Reference Point P4—the distal tip of the stem. recognized that for some materials the environment may have
3.1.11 Reference Point P6 — the intersection of the canti- an effect on the response to cyclic loading. The test environ-
lever plane with the medial surface of the stem in the A-P ment used and the rationale for the choice of that environment
projection. should be described in the report.
3.1.12 R value—the R value is the ratio of the minimum 4.2 It is recognized that actual in vivo loading conditions are
force to the maximum force. not constant amplitude. However, there is not sufficient infor-
mation available to crate standard load spectrums for metallic
minimum force
R 5
stemmed femoral components. Accordingly, a simple periodic
maximum force
constant amplitude force is recommended.
3.1.13 Stem Reference Angle X—the angle between the stem
4.3 In order for fatigue data on femoral stems to be useful
reference line and the line of load application.
for comparison, it must be reproducible among different
3.1.14 stem reference line—a line passing through Refer-
laboratories. Consequently, it is essential that uniform proce-
ence Point P6 and the center of the prosthesis head (P1).
dures be established.
3.1.15 supported stem length—the vertical distance be-
tween the distal tip of the stem (P4) and the cantilever plane.
5. Specimen Selection
3.1.16 unloaded moment arm—the perpendicular distance
5.1 The specimen selection should have the same geometry
between the line of load application and the geometric centroid
as the final finished product, and the stem should be in the final
of the stem cross section at the cantilever plane.
finished condition.
3.1.17 unsupported stem length—the vertical distance be-
tween Point P3 and the cantilever plane.
6. Apparatus
3.2 See Figs. 1 and 2.
6.1 The specimen shall be constrained by a suitable grouting
agent within a rigid cavity. A common grouting agent used is
poly methyl methacrylate (PMMA—bone cement) that is
polymerized in place. The minimum thickness of the grouting
agent should be 1 cm. Although bone cement is the recom-
mended grouting agent, other material may be used provided it
does not chemically or mechanically interact with the test
specimen.
6.2 The test fixtures shall be constructed so that the line of
load application is in the implant anterior/posterior symmetry
plane of the supported portion of the stem.
6.3 The test fixtures shall be constructed so that the line of
load application passes through the ball center.
6.4 A ball- or roller-bearing low-friction mechanism shall
be included in the loading apparatus to minimize loads not
perpendicular to the cantilever plane. An example of such a
mechanism is included in Appendix X1.
7. Equipment Characteristics
7.1 The action of the machine should be analyzed to ensure
that the desired form and periodic force amplitude is main-
tained for the duration of the test. (See Practice E 467.)
7.2 The test machine should have a load monitoring system
such as the transducer mounted in line with the specimen. The
test loads should be monitored continuously in the early stages
FIG. 2 Collarless Device
of the test and periodically thereafter to ensure the desired load
cycle is maintained. The varying load as determined by
4. Significance and Use
suitable dynamic verification should be maintained at all times
4.1 This practice can be used to describe the effects of
to within 62 % of the maximum force being used.
materials, manufacturing, and design variables on the fatigue
8. Procedure
resistance of metallic stemmed femoral components subjected
8.1 Specimen Test Orientation—The angle between the
distal stem axis and the line of load application shall be 10 6
The reference points and lines are consistent with the Proposed Standard
1 deg %. An example of a method to accomplish mounting the
Specification for Cementable Total Hip Prostheses with Femoral Stems. The
stem at the desired angle is given in Appendix X2.
reference points “P2” and “P5” in that proposed specification are not relevant to this
practice. Consequently, they are not used in this practice. 8.2 Specimen Mounting:
NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
F 1440
8.2.1 Maintain the stem Reference Angle X within a range 9. Test Termination
of 61 deg over a test group.
9.1 Continue the test until the specimen fails or until a
8.2.2 Maintain the unsupported stem length at 62 mm.
predetermined number of cycles has been applied to the
8.2.3 No relative motion between the prosthesis and the
specimen. Failure should be defined as a complete separation,
grouting agent is permitted during hardening of the grouting
or exceeding of a deflection limit on a test machine. In
agent.
reporting results, state the criteria selected for defining failure
8.2.4 The surface of the grouting agent at the cantilever
and the number of cycles shown as the predetermined runout of
plane shall be approximately level and perpendicular to the line
the test. Discard the data for a specific sample if the grouting
of load application.
agent fractured prior to test completion.
8.2.5 An example of a technique for setting a specimen in
10. Report
the grouting agent in the correct orientation is given in
Appendix X2. 10.1 Report the fatigue test specimens, procedures, and
8.3 Test Frequency— Run all tests at a test frequency of 30 results in accordance with Recommended Practice E 468.
10.2 In addition, report the following parameters: Stem
Hz or less.
8.4 R Value—Run all tests with an R value of 10.0. Reference Angle X, supported stem length, maximum force, R
value, specimen material, cycles to failure, location of fractures
8.5 Measure the unsupported stem length, stem reference
angle, and moment arm for each test specimen p
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