ASTM F1800-97
(Test Method)Standard Test Method for Cyclic Fatigue Testing of Metal Tibial Tray Components of Total Knee Joint Replacements
Standard Test Method for Cyclic Fatigue Testing of Metal Tibial Tray Components of Total Knee Joint Replacements
SCOPE
1.1 This test method covers a procedure for the fatigue testing of metallic tibial trays used in knee joint replacements. This standard covers the procedures for the performance of fatigue tests on metallic tibial components using a cyclic, constant-amplitude force. It applies to tibial trays which cover both the medial and lateral plateaus of the tibia. This test method may require modifications to accommodate other tibial tray designs.
1.2 This test method is intended to provide useful, consistent, and reproducible information about the fatigue performance of metallic tibial trays with one unsupported condyle.
1.3 The values stated in SI units are regarded as the standard. The inch-pound units given in parentheses are for information only.
1.4 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
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Standards Content (Sample)
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Designation: F 1800 – 97
Standard Test Method for
Cyclic Fatigue Testing of Metal Tibial Tray Components of
Total Knee Joint Replacements
This standard is issued under the fixed designation F 1800; 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 3.2 Definitions of Terms Specific to This Standard:
3.2.1 anteroposterior centerline—a line that passes through
1.1 This test method covers a procedure for the fatigue
the center of the tibial tray, parallel to the sigittal plane and
testing of metallic tibial trays used in knee joint replacements.
perpendicular to the line of load application. For asymmetric
This standard covers the procedures for the performance of
tibial tray designs, the appropriate center of the tibial tray shall
fatigue tests on metallic tibial components using a cyclic,
be determined by the investigator and the rationale reported.
constant-amplitude force. It applies to tibial trays which cover
3.2.2 fixture centerline—a line that passes through the
both the medial and lateral plateaus of the tibia. This test
center of the fixture, parallel to the anteroposterior centerline.
method may require modifications to accommodate other tibial
This line represents the separation between the supported and
tray designs.
unsupported portions of the test fixture.
1.2 This test method is intended to provide useful, consis-
3.2.3 mediolateral centerline—a line that passes through
tent, and reproducible information about the fatigue perfor-
the center of the tibial tray, parallel to the coronal, or frontal,
mance of metallic tibial trays with one unsupported condyle.
plane and perpendicular to the line of load application. For
1.3 The values stated in SI units are regarded as the
asymmetric tibial tray designs, the appropriate center of the
standard. The inch-pound units given in parentheses are for
tibial tray shall be determined by the investigator and the
information only.
rationale reported.
1.4 This standard does not purport to address all of the
3.2.4 moment arm “d ”—the perpendicular distance be-
ap
safety concerns, if any, associated with its use. It is the
tween the mediolateral centerline of the tibia component and
responsibility of the user of this standard to establish appro-
the line of load application.
priate safety and health practices and determine the applica-
3.2.5 moment arm “d ”—the perpendicular distance be-
ml
bility of regulatory limitations prior to use.
tween the anteroposterior centerline of the tibia component and
2. Referenced Documents the line of load application.
2.1 ASTM Standards:
4. Significance and Use
E 4 Practices for Force Verification of Testing Machines
4.1 This test method can be used to describe the effects of
E 467 Practice for Verification of Constant Amplitude Dy-
2 materials, manufacturing, and design variables on the fatigue
namic Loads in an Axial Load Fatigue Testing System
performance of metallic tibial trays subject to cyclic loading
E 468 Practice for the Presentation of Constant Amplitude
2 for relatively large numbers of cycles.
Fatigue Results for Metallic Materials
4.2 The loading of tibial tray designs in vivo will, in general,
E 1150 Definitions of Terms Relating to Fatigue
differ from the loading defined in this test method. The results
3. Terminology
obtained here cannot be used to directly predict in vivo
performance. However, this test method is designed to allow
3.1 Definitions:
for comparisons between the fatigue performance of different
3.1.1 R value—The R value is the ratio of the minimum load
metallic tibial tray designs, when tested under similar condi-
to the maximum load.
tions.
minimum load
4.3 In order for fatigue data on tibial trays to be comparable,
R 5 (1)
maximum load
reproducible, and capable of being correlated among laborato-
ries, it is essential that uniform procedures be established.
This test method is under the jurisdiction of ASTM Committee F-4 on Medical
5. Specimen Selection
and Surgical Materials and Devices and is the direct responsibility of Subcommittee
F04.22 on Arthroplasty .
5.1 The test component selected shall have the same geom-
Current edition approved April 10, 1997. Published February 1998.
2 etry as the final product, and shall be in finished condition.
Annual Book of ASTM Standards, Vol 03.01.
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NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
F1800–97
6. Apparatus a minimum thickness of 6 mm (0.25 in.), measured at the dome
of the sphere. It is recommended that the diameter of the spacer
6.1 The tibial tray shall be mounted as a cantilever beam
is 13 mm (0.5 in.).
(see Fig. 1 and Fig. 2). Care shall be taken to ensure that the
fixation of the tibial tray does not produce abnormal stress
NOTE 1—Actual dimensions of the spacer may vary as smaller tibial
concentrations that could change the failure mode of the part.
tray designs may require a smaller diameter disk.
One possible setup involving fixation of the inferior surface or
6.4.1 The spacer shall be placed on the unsupported tibial
clamping of the superior surface is shown in Fig. 1 and Fig. 2.
condyle. The purpose of the spacer is to distribute load to the
If necessary, bone cement or other high strength epoxy may be
tibial tray condyle and to eliminate possible fretting fatigue
used on the supported aspect of the tibial tray to prevent
initiated by contact between the metal indenter and the tibial
loosening during the test.
tray.
6.2 The tibial tray shall be positioned such that the antero-
6.5 The fixturing shall be constructed so that the load shall
posterior centerline and the fixture centerline are aligned with
be applied perpendicular to the undeflected superior surface of
an accuracy of 6 1mminthe x direction and6 2° in the x–y
the tibial tray.
plane (see Fig. 1 and Fig. 2).
6.6 The point of load application shall be located at a known
6.3 When the tibial tray design includes a central keel or
distance from the anteroposterior centerline (d ) and from the
ml
other prominence, the proper method for support of the keel
mediolateral centerline (d ) .
ap
must be determined. Depending on the tibial tray design, it may
6.7 The load shall be applied by means of a spherical
be necessary to evaluate the design with or without support of
indenter, a diameter of 32 mm (1.25 in.) is recommended.
the keel (see Fig. 2). The method of supporting (or not
7. Equipment Characteristics
supporting) any such feature shall be reported.
6.4 A spacer of plastic possessing sufficient stiffness and 7.1 Perform the tests on a fatigue test machine with ad-
creep resistance (for example, ultra high molecular weight equate load capacity.
polyethylene, acetal co-polymer) shall be placed between the 7.2 Analyze the action of the machine to ensure that the
tibial tray and the load applicator (see Fig. 3). The spacer shall desired form and periodic force amplitude is maintained for the
contain a spherical indentation (or recess) for the spherical duration of the test (see Practice E 467 or use a validated strain
indenter. This recess shall be greater to or equal than the gaged part).
diameter of the spherical indenter and is included to minimize 7.3 The test machine shall have a load monitoring system
the chance of spacer fracture under load. The spacer shall have such as the transducer mounted in line with the specimen.
FIG. 1 Schematic of Test Setup Without a Central Keel
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
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F1800–97
FIG. 2 Schematic or Test Setup With a Central Keel
FIG. 3 Recommended Spacer Drawing
Monitor the test loads continuously in the early stages of the 8.2 Position the test specimen such that the load axis is
test and periodically thereafter to ensure the desired load cycle perpendicular to the undeflected superior surface of the tray
is maintained. Maintain the varying load as determined by
since the tray surface will not remain perpendicular to the load
suitable dynamic verification at all times to within 6 2% of
axis during loading.
the largest compressive force being used.
8.3 Mount one side of a symmetric tibial component on the
fixture (see Fig. 1 and Fig. 2). Use the centerline of the tray to
8. Procedure
distinguish between supported and non supported sides. If
8.1 Determine the size of the tibial tray component used by
asymmetrical, fix the tibial component such that a worst case
the investigator. Dimensions shall be reported.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
F1800–97
condition is tested. Report the criteria used to distinguish crack detectable by eye, fluorescent dye penetrant, or other
between supported and not supporte
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