Standard Practice for Gravimetric Measurement of Polymeric Components for Wear Assessment

SIGNIFICANCE AND USE
This practice uses a weight-loss method of wear determination for the polymeric components or materials used in human joint prostheses, using serum or demonstrated equivalent fluid for lubrication, and running under a load profile representative of the appropriate human joint application (1,2).4 The basis for this weight-loss method for wear measurement was originally developed (3) for pin-on-disk wear studies (Practice F 732) and has been extended to total hip replacements (4, 5, ISO 14242–2, and Guide F 1714) and to femoro-tibial knee prostheses (6 and ISO 14243–2), and to femoro-patellar knee prostheses (6,7).
While wear results in a change in the physical dimensions of the specimen, it is distinct from dimensional changes due to creep or plastic deformation, in that wear results in the removal of material in the form of polymeric debris particles, causing a loss in weight of the specimen.
This practice for measuring wear of the polymeric component is suitable for various simulator devices. These techniques can be used with metal, ceramic, carbon, polymeric, and composite counter faces bearing against a polymeric material (for example, polyethylene, polyacetal, and so forth). Thus, this weight-loss method has universal application for wear studies of human joint replacements which feature polymeric bearings. This weight-loss method has not been validated for non-polymeric material bearing systems, such as metal-metal, carbon-carbon, or ceramic-ceramic. Progressive wear of such rigid bearing combinations has generally been monitored using a linear, variable-displacement transducers, or by other profilometric techniques.
SCOPE
1.1 This practice describes a laboratory method using a weight-loss (that is, mass-loss; see X1.4) technique for evaluating the wear properties of polymeric materials or devices which are being considered for use as bearing surfaces of human joint replacement prostheses, or both. The test specimens are evaluated in a device intended to simulate the tribological conditions encountered in the human joint; for example, use of a fluid such as bovine serum, or equivalent pseudosynovial fluid shown to simulate similar wear mechanisms and debris generation as found in vivo.

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Publication Date
28-Feb-2006
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ASTM F2025-06 - Standard Practice for Gravimetric Measurement of Polymeric Components for Wear Assessment
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: F2025 − 06
StandardPractice for
Gravimetric Measurement of Polymeric Components for
1
Wear Assessment
This standard is issued under the fixed designation F2025; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope human joint prostheses, using serum or demonstrated equiva-
lent fluid for lubrication, and running under a load profile
1.1 This practice describes a laboratory method using a
representative of the appropriate human joint application
weight-loss (that is, mass-loss; see X1.4) technique for evalu-
4
(1,2). The basis for this weight-loss method for wear mea-
ating the wear properties of polymeric materials or devices
surement was originally developed (3) for pin-on-disk wear
which are being considered for use as bearing surfaces of
studies (Practice F732) and has been extended to total hip
human joint replacement prostheses, or both. The test speci-
replacements (4, 5, ISO14242–2, and Guide F1714) and to
mens are evaluated in a device intended to simulate the
femoro-tibial knee prostheses (6 and ISO14243–2), and to
tribological conditions encountered in the human joint; for
femoro-patellar knee prostheses (6,7).
example, use of a fluid such as bovine serum, or equivalent
pseudosynovial fluid shown to simulate similar wear mecha- 3.2 While wear results in a change in the physical dimen-
nisms and debris generation as found in vivo. sions of the specimen, it is distinct from dimensional changes
due to creep or plastic deformation, in that wear results in the
2. Referenced Documents
removal of material in the form of polymeric debris particles,
2
causing a loss in weight of the specimen.
2.1 ASTM Standards:
D792Test Methods for Density and Specific Gravity (Rela-
3.3 This practice for measuring wear of the polymeric
tive Density) of Plastics by Displacement
component is suitable for various simulator devices. These
D1505Test Method for Density of Plastics by the Density-
techniquescanbeusedwithmetal,ceramic,carbon,polymeric,
Gradient Technique
and composite counter faces bearing against a polymeric
F732Test Method for Wear Testing of Polymeric Materials
material (for example, polyethylene, polyacetal, and so forth).
Used in Total Joint Prostheses
Thus, this weight-loss method has universal application for
F1714GuideforGravimetricWearAssessmentofProsthetic
wear studies of human joint replacements which feature
Hip Designs in Simulator Devices
polymeric bearings. This weight-loss method has not been
3
2.2 Other Standards:
validated for non-polymeric material bearing systems, such as
ISO14242–2ImplantsforSurgery—WearofTotalHip-Joint
metal-metal, carbon-carbon, or ceramic-ceramic. Progressive
Prostheses—Part 2: Methods of Measurement
wear of such rigid bearing combinations has generally been
ISO14243–2Implants for Surgery—Wear of Total Knee-
monitoredusingalinear,variable-displacementtransducers,or
Joint Prostheses—Part 2: Methods of Measurement
by other profilometric techniques.
3. Significance and Use
4. Components and Materials
3.1 This practice uses a weight-loss method of wear deter- 4.1 Hip Prosthesis Components—The hip joint prosthesis
mination for the polymeric components or materials used in
comprises a ball-and-socket configuration in which materials
such as polymers, composites, metal alloys, ceramics, and
carbon have been used in various combinations and designs.
1
ThispracticeisunderthejurisdictionofASTMCommitteeF04onMedicaland
4.1.1 Component Configurations—The diameter of the
Surgical Materials and Devices and is the direct responsibility of Subcommittee
prosthetic ball may vary from 22 to 54 mm or larger. The
F04.22 on Arthroplasty.
Current edition approved March 1, 2006. Published March 2006. Originally
design may include ball-socket, trunnion, bipolar, or other
approved in 2000. Last previous edition approved in 2000 as F2025–00. DOI:
configurations. If applicable, the normal metal backing for the
10.1520/F2025-06.
polymeric component shall be used provided disassembly and
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM reassembly of these components for the measurement does not
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
3 4
Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St., Theboldfacenumbersinparenthesesrefertothelistofreferencesattheendof
4th Floor, New York, NY 10036. this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United Stat
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