ASTM F2723-13a

Standard Test Method for Evaluating Mobile Bearing Knee Tibial Baseplate/Bearing Resistance to Dynamic Disassociation

SIGNIFICANCE AND USE
3.1 This test method includes the use of static and fatigue shear and bending force conditions to evaluate the bearing retention mechanism of a mobile bearing knee design and its ability to prevent disassociation.  
3.2 In general, disassociation does not occur during activities where the contact locations are within the boundaries of the bearing surfaces. Disassociation is most likely to occur with forces at the edges of the bearing component or with large AP shear forces on a posterior stabilized knee tibial component post. Extreme bearing rotation, bone/bearing impingement, severe varus or valgus moments, high flexion or any combination of the above can increase the likelihood of disassociation.  
3.3 The test method described is applicable to any bicompartmental mobile bearing knee with a bearing retention mechanism. With modification, the test can be applied to a unicompartmental mobile bearing knee with a bearing retention mechanism.
SCOPE
1.1 This test method describes a laboratory method for evaluating the potential for mobile bearing knee tibial baseplate/bearing disassociation under repeated forces.  
1.2 The test described is applicable to any bicompartmental mobile bearing knee with a bearing retention mechanism. With modification, the test can be applied to a unicompartmental mobile bearing knee with a bearing retention mechanism.  
1.3 Although the methodology described does not replicate all physiological force conditions, it is a means of in vitro comparison of mobile bearing knee designs and the strength of the bearing retention mechanism between the tibial baseplate and bearing components under the stated test conditions.  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.5 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: 14-Jul-2013
• ICS: 11.040.40 - Implants for surgery, prosthetics and orthotics
• Technical Committee: F04 - Medical and Surgical Materials and Devices
• Drafting Committee: F04.22 - Arthroplasty

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: F2723 − 13a
Standard Test Method for
Evaluating Mobile Bearing Knee Tibial Baseplate/Bearing
1
Resistance to Dynamic Disassociation
This standard is issued under the fixed designation F2723; 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 maximum with anterior-posterior (AP) movement of the femo-
ral component on the bearing.
1.1 This test method describes a laboratory method for
evaluating the potential for mobile bearing knee tibial
2.1.5 mobile bearing—the component between fixed femo-
baseplate/bearing disassociation under repeated forces.
ral and tibial knee components with an articulating surface on
both the inferior and superior sides.
1.2 The test described is applicable to any bicompartmental
mobile bearing knee with a bearing retention mechanism. With
2.1.6 mobile bearing knee system—a knee prosthesis
modification, the test can be applied to a unicompartmental
system, comprised of a tibial component, a mobile bearing
mobile bearing knee with a bearing retention mechanism.
component that can rotate or rotate and translate relative to the
1.3 Although the methodology described does not replicate
tibial component, and a femoral component.
all physiological force conditions, it is a means of in vitro
2.1.7 superior articulating interfaces—any interface in
comparison of mobile bearing knee designs and the strength of
whichrelativemotionoccursbetweenthetopsideofthemobile
the bearing retention mechanism between the tibial baseplate
bearing component and the femoral bearing component.
and bearing components under the stated test conditions.
2.1.8 tibial baseplate/bearing disassociation— unrecover-
1.4 The values stated in SI units are to be regarded as
able physical separation of the bearing and tibial baseplate
standard. No other units of measurement are included in this
components as a result of bearing distraction or tilting.
standard.
1.5 This standard does not purport to address all of the 2.1.9 2-axis orthogonal load frame—a test machine capable
safety concerns, if any, associated with its use. It is the
of applying forces and displacements that act at 90° to each
responsibility of the user of this standard to establish appro-
other.
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
3. Significance and Use
2. Terminology 3.1 This test method includes the use of static and fatigue
shear and bending force conditions to evaluate the bearing
2.1 Definitions:
retention mechanism of a mobile bearing knee design and its
2.1.1 bearing axis—the line connecting the lowest points on
ability to prevent disassociation.
both the lateral and medial condyles of the superior surface of
the mobile bearing.
3.2 In general, disassociation does not occur during activi-
2.1.2 bearing retention mechanism—mechanical means pre-
tieswherethecontactlocationsarewithintheboundariesofthe
venting tibial baseplate/bearing disassociation.
bearing surfaces. Disassociation is most likely to occur with
forces at the edges of the bearing component or with large AP
2.1.3 inferior articulating interfaces—any interface in
shear forces on a posterior stabilized knee tibial component
which relative motion occurs between the underside of the
post. Extreme bearing rotation, bone/bearing impingement,
mobile bearing component and the tibial tray.
severe varus or valgus moments, high flexion or any combi-
2.1.4 limiting position—the position of the femoral compo-
nation of the above can increase the likelihood of disassocia-
nent relative to the bearing at which the shear force is at a
tion.
1 3.3 The test method described is applicable to any bicom-
This test method is under the jurisdiction ofASTM Committee F04 on Medical
and Surgical Materials and Devices and is the direct responsibility of Subcommittee
partmental mobile bearing knee with a bearing retention
F04.22 on Arthroplasty.
mechanism. With modification, the test can be applied to a
Current edition approved July 15, 2013. Published August 2013. Originally
unicompartmental mobile bearing knee with a bearing reten-
approved in 2008. Last previous version approved in 2013 as F2723 – 13. DOI:
10.1520/F2723-13A. tion mechanism.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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F2723 − 13a
4. Apparatus and Materials
4.1 A2-axisorthogonalloadframewithfeedbackcontrolon
bothaxesberequiredfordislocationtesting.Themachinemust
be able to record force and displacement in both axes.
4.1.1 Comp
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: F2723 − 13 F2723 − 13a
Standard Test Method for
Evaluating Mobile Bearing Knee Tibial Baseplate/Bearing
1
Resistance to Dynamic Disassociation
This standard is issued under the fixed designation F2723; 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
1.1 This test method describes a laboratory method for evaluating the potential for mobile bearing knee tibial baseplate/bearing
disassociation under repeated forces.
1.2 The test described is applicable to any bicompartmental mobile bearing knee with a bearing retention mechanism. With
modification, the test can be applied to a unicompartmental mobile bearing knee with a bearing retention mechanism.
1.3 Although the methodology described does not replicate all physiological force conditions, it is a means of in vitro
comparison of mobile bearing knee designs and the strength of the bearing retention mechanism between the tibial baseplate and
bearing components under the stated test conditions.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.5 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.
2. Terminology
2.1 Definitions:
2.1.1 bearing axis—the line connecting the lowest points on both the lateral and medial condyles of the superior surface of the
mobile bearing.
2.1.2 bearing retention mechanism—mechanical means preventing tibial baseplate/bearing disassociation.
2.1.3 inferior articulating interfaces—any interface in which relative motion occurs between the underside of the mobile
bearing component and the tibial tray.
2.1.4 limiting position—the position of the femoral component relative to the bearing at which the shear force is at a maximum
with anterior-posterior (AP) movement of the femoral component on the bearing.
2.1.5 mobile bearing—the component between fixed femoral and tibial knee components with an articulating surface on both
the inferior and superior sides.
2.1.6 mobile bearing knee system—a knee prosthesis system, comprised of a tibial component, a mobile bearing component that
can rotate or rotate and translate relative to the tibial component, and a femoral component.
2.1.7 superior articulating interfaces—any interface in which relative motion occurs between the topside of the mobile bearing
component and the femoral bearing component.
2.1.8 tibial baseplate/bearing disassociation— unrecoverable physical separation of the bearing and tibial baseplate compo-
nents as a result of bearing distraction or tilting.
2.1.9 2-axis orthogonal load frame—a test machine capable of applying forces and displacements that act at 90° to each other.
3. Significance and Use
3.1 This test method includes the use of static and fatigue shear and bending force conditions to evaluate the bearing retention
mechanism of a mobile bearing knee design and its ability to prevent disassociation.
1
This test method is under the jurisdiction of ASTM Committee F04 on Medical and Surgical Materials and Devices and is the direct responsibility of Subcommittee
F04.22 on Arthroplasty.
Current edition approved Feb. 1, 2013July 15, 2013. Published February 2013August 2013. Originally approved in 2008. Last previous version approved in 20082013
as F2723 – 08.F2723 – 13. DOI: 10.1520/F2723-13.10.1520/F2723-13A.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
F2723 − 13a
3.2 In general, disassociation does not occur during activities where the contact locations are within the boundaries of the
bearing surfaces. Disassociation is most likely to occur with forces at the edges of the bearing component or with large AP shear
forces on a posterior stabilized knee tibial component post. Extreme bearing rotation, bone/bearing impingement, severe varus or
valgus moments, high flexion or any combination of the above can increase the likelihood of disassociation.
3.3 The test method described is applicable to any bicompartmental mobile bearing knee with a bea
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