ASTM F1800-19e1

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
´1
Designation: F1800 − 19
Standard Practice for
Cyclic Fatigue Testing of Metal Tibial Tray Components of
Total Knee Joint Replacements
This standard is issued under the fixed designation F1800; 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.
ε NOTE—Section 8.2 was corrected editorially in January 2020.
1. Scope E467 Practice for Verification of Constant Amplitude Dy-
namic Forces in an Axial Fatigue Testing System
1.1 This practice covers a procedure for the fatigue testing
E468 Practice for Presentation of Constant Amplitude Fa-
of metallic tibial trays used in knee joint replacements using a
tigue Test Results for Metallic Materials
cyclic, constant-amplitude force. It applies to tibial trays that
F2083 Specification for Knee Replacement Prosthesis
cover both the medial and lateral plateaus of the tibia. This
practicemayrequiremodificationstoaccommodateothertibial
3. Terminology
tray designs.
3.1 Definitions of Terms Specific to This Standard:
1.2 This practice is intended to provide useful, consistent,
3.1.1 anteroposterior centerline—line that passes through
and reproducible information about the fatigue performance of
the center of the tibial tray, parallel to the sagittal plane and
metallic tibial trays with one unsupported condyle. The results
perpendicular to the line of load application. For asymmetric
are applicable to the laboratory test conditions and may not
tibial tray designs, the appropriate center of the tibial tray shall
correlate with in vivo performance.
be determined by the investigator and the rationale reported.
1.3 The values stated in SI units are to be regarded as
3.1.2 fixture centerline—line that passes through the center
standard. No other units of measurement are included in this
of the fixture, parallel to the anteroposterior centerline. This
standard.
line represents the separation between the supported and
1.4 This standard does not purport to address all of the
unsupported portions of the test fixture.
safety concerns, if any, associated with its use. It is the
3.1.3 mediolateral centerline—line that passes through the
responsibility of the user of this standard to establish appro-
center of the tibial tray, parallel to the coronal, or frontal, plane
priate safety, health, and environmental practices and deter-
and perpendicular to the line of load application. For asym-
mine the applicability of regulatory limitations prior to use.
metric tibial tray designs, the appropriate center of the tibial
1.5 This international standard was developed in accor-
tray shall be determined by the investigator and the rationale
dance with internationally recognized principles on standard-
reported.
ization established in the Decision on Principles for the
3.1.4 moment arm, d —the perpendicular distance between
Development of International Standards, Guides and Recom-
ap
the mediolateral centerline of the tibia component and the line
mendations issued by the World Trade Organization Technical
of load application.
Barriers to Trade (TBT) Committee.
3.1.5 moment arm, d —the perpendicular distance between
ml
2. Referenced Documents
the anteroposterior centerline of the tibia component and the
2.1 ASTM Standards: line of load application.
E4 Practices for Force Verification of Testing Machines
4. Significance and Use
4.1 This practice can be used to describe the effects of
ThispracticeisunderthejurisdictionofASTMCommitteeF04onMedicaland
materials, manufacturing, and design variables on the fatigue
Surgical Materials and Devices and is the direct responsibility of Subcommittee
F04.22 on Arthroplasty.
performance of metallic tibial trays subject to cyclic loading
Current edition approved Oct. 1, 2019. Published January 2020. Originally
for relatively large numbers of cycles.
approved in 1997. Last previous edition approved in 2012 as F1800–12. DOI:
10.1520/F1800-19E01.
4.2 Theloadingoftibialtraydesigns in vivowill,ingeneral,
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
differ from the loading defined in this practice. The results
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
obtained here cannot be used to directly predict in-vivo
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. performance. However, this practice is designed to allow for
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
´1
F1800 − 19
comparisons between the fatigue performance of different
metallic tibial tray designs, when tested under similar condi-
tions.
4.3 Inorderforfatiguedataontibialtraystobecomparable,
reproducible, and capable of being correlated among
laboratories, it is essential that uniform procedures be estab-
lished.
5. Specimen Selection
5.1 The test component selected shall have the same geom-
etry as the final product, and shall be in finished condition.
6. Apparatus
6.1 The tibial tray shall be mounted as a cantilever beam
(see Fig. 1 and Fig. 2). Care shall be taken to ensure that the
fixation of the tibial tray does not produce abnormal stress
concentrations that could change the failure mode of the part.
One possible setup involving fixation of the inferior surface
and/or clamping of the superior surface is shown in Fig. 1 and
Fig. 2. If necessary, bone cement or other high-strength epoxy
may be used on the supported aspect of the tibial tray to
prevent loosening during the test. Ensure that there is a
clearance of at least 5 mm between the undersurface of the
loaded compartment on the tibial tray and any part of the
fixture.
NOTE1—TheloadapplicatorandthespacerdisplayedinFig.1andFig.
FIG. 2 Schematic of Test Setup With a Central Keel
2 is an example. Other methods to meet the requirement given by 7.4
might be used.
6.2 The tibial tray shall be positioned such that the antero-
posterior centerline and the fixture centerline are aligned with
an accuracy of 61mminthe x direction and 62° in the x–y
plane (see Fig. 1 and Fig. 2).
6.3 When the tibial tray design includes a central keel or
other prominence, only the medial or lateral half of the keel
shall be supported (see 8.3 and Fig. 2).
6.4 A spacer of plastic possessing sufficient stiffness and
creep resistance (for example, ultra high molecular weight
polyethylene, acetal co-polymer) shall be placed between the
tibial tray and the load applicator (see Fig. 3). The spacer shall
contain a spherical indentation (or recess) for the spherical
indenter. This recess shall be greater than or equal to the
FIG. 3 Recommended Spacer Drawing
diameter of the spherical indenter and is included to minimize
the chance of spacer fracture under load. The spacer shall have
a minimum thickness of 6 mm, measured at the dome of the
sphere.Itisrecommendedthatthediameterofthespacerbe13
mm.
NOTE 2—Actual dimensions of the spacer may vary as smaller tibial
tray designs may require a smaller diameter disk.
NOTE3—Metalmightbeusedasthespacermaterialiftheplasticspacer
is not capable of transferring the test load.
6.4.1 The spacer shall be placed on the unsupported tibial
FIG. 1 Schematic of Test Setup Without a Central Keel condyle. The purpose of the spacer is to distribute load to the
´1
F1800 − 19
NOTE 6—The spacer might be glued onto the tibial tray.
tibial tray condyle and to eliminate possible fretting fatigue
initiated by contact between the metal indenter and the tibial
8. Procedure
tray.
8.1 Determine the size of the tibial tray component used by
6.5 The fixturing shall be constructed so that the load shall
the investigator. Dimensions shall be reported.
be applied perpendicular to the undeflected superior surface of
8.2 Position the test specimen such that the load axis is
the tibial tray.
perpendicular to the undeflected superior surface of the tray
6.6 Use one of the following two methods for determining
since the tray surface will not remain perpendicular to the load
the position of the loading point.
axis during loading.
6.6.1 For tibial articulating surface designs that have a
8.3 Mount one side of a symmetric tibial component on the
concavesurface,theloadingpointshallbetheintersectionwith
fixture (see Fig. 1 and Fig. 2). Use the centerline of the tray to
the tray of a line perpendicular to the tray that intersects the
distinguish between the supported and non-supported sides. If
deepest part of the concave recess of the articulating surface of
asymmetrical, fix the tibial component such that a worst-case
thetibialcomponent.Thetolerancefor d and d is 60.5mm.
ap ml
condition is tested. Report the criteria for which side of the
6.6.2 For other tibial designs, the femoral component, the
tibial tray (medial or lateral) was chosen for load application
tibial articulating surface, and the tibial tray shall be assembled
(i.e., how the worst-case side was chosen for testing).
at 0° flexion and the position of the center of pressure
determined. The tolerance for d and d is 60.5mm. The
ap ml
8.4 Apply a load as given by Specification F2083 by means
loading point shall be the intersection of the line perpendicular
of a spherical indenter. The number of specimens is given by
tothetraythatintersectsthecenterofthepressurecontactarea.
Specification F2083.
NOTE 4—Optionally, define the worst-case scenario considering the
8.5 Test frequency—Run all tests at a frequency of 10 Hz or
potential translation in the transverse plane and/or the potential axial
less. Higher test frequencies might be used if evidence is
rotation (1) of the femoral component relative to the tibial baseplate, and
provided that the test results are identical to those obtained at
apply 6.6.1 or 6.6.2. The rationale for the choice of femoral component
10 Hz or less. Take care to ensure that the test machine can
placement relative to the tibial baseplate should be reported.
NOTE 5—If the geometry of the tibial baseplate superior surface maintain the applied load at the chosen frequency and that
prevents using d and d for the load application (for example, the
ap ml
resonant conditions are not reached.
presence of protrusion at the location of the theoretical load application),
8.6 The test shall be conducted under force control using a
the rationale for the choice of the a
...