ASTM F1875-98(2004)
(Practice)Standard Practice for Fretting Corrosion Testing of Modular Implant Interfaces: Hip Femoral Head-bore and Cone Taper Interface
Standard Practice for Fretting Corrosion Testing of Modular Implant Interfaces: Hip Femoral Head-bore and Cone Taper Interface
SIGNIFICANCE AND USE
The modular interfaces of total joint prostheses are subjected to micromotion that could result in fretting and corrosion. The release of corrosion products and particulate debris could stimulate adverse biological reactions, as well as lead to accelerated wear at the articulation interface. Methods to assess the stability and corrosion resistance of the modular interfaces, therefore, are an essential component of device testing.
Long-term in vitro testing is essential to produce damage and debris from fretting of a modular interface (4,5). The use of proteinaceous solutions is recommended to best simulate the in vivo environment.
Short-term tests often can be useful in evaluations of differences in design during device development (1-4). The electrochemical methods provide semiquantitative measures of fretting corrosion rates. The relative contributions of mechanical and electrochemical processes to the total corrosion and particulate release phenomena, however, have not been established; therefore, these tests should not be utilized to compare the effects of changes in material combinations, but rather be utilized to evaluate design changes of bore (head) and cone (stem) components.
These tests are recommended for evaluating the fretting wear and corrosion of modular interfaces of hip femoral head and stem components. Similar methods may be applied to other modular interfaces where fretting corrosion is of concern.
These methods are recommended for comparative evaluation of the fretting wear and corrosion of new materials, coatings, or designs, or a combination thereof, under consideration for hip femoral head and neck modular interfaces. Components for testing may be those of a manufactured modular hip device (finished product) or sample coupons, which are designed and manufactured for simulation of the head, taper, and neck region of a modular hip device.
SCOPE
1.1 This practice describes the testing, analytical, and characterization methods for evaluating the mechanical stability of the bore and cone interface of the head and stem junction of modular hip implants subjected to cyclic loading by measurements of fretting corrosion. (1-5) Two test methods described are as follows:
1.1.1 Method I-The primary purpose of this method is to provide a uniform set of guidelines for long-term testing to determine the amount of damage by measurement of the production of corrosion products and particulate debris from fretting and fretting corrosion. Damage also is assessed by characterization of the damage to the bore and cone surfaces. (4,5)
1.1.2 Methods II-This method provides for short-term electrochemical evaluation of the fretting corrosion of the modular interface. It is not the intent of this method to produce damage nor particulate debris but rather to provide a rapid method for qualitative assessment of design changes which do not include material changes. (1-4)
1.2 This practice does not provide for judgment or prediction of in vivo implant performance, but rather, provides for a uniform set of guidelines for evaluating relative differences in performance between differing implant designs, constructs, or materials with performance defined in the context of the amount of fretting and fretting corrosion. Also, this practice should permit direct comparison of fretting corrosion data between independent research groups, and thus, provide for building of a data base on modular implant performance.
1.3 This practice provides for comparative testing of manufactured hip femoral heads and stems and for coupon type specimen testing where the male taper portion of the modular junction does not include the entire hip implant, with the taper portion of the coupon identical in design, manufacturing, and materials to the taper of the final hip implant. (4,5)
1.4 Method I of this practice has been provided in a manner to permit simultaneous evaluation of the fatigue strength of a femor...
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Designation:F1875–98 (Reapproved2004)
Standard Practice for
Fretting Corrosion Testing of Modular Implant Interfaces:
Hip Femoral Head-Bore and Cone Taper Interface
This standard is issued under the fixed designation F1875; 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 1.4 Method I of this practice has been provided in a manner
to permit simultaneous evaluation of the fatigue strength of a
1.1 This practice describes the testing, analytical, and char-
femoral hip stem (in accordance with Practice F1440) and the
acterization methods for evaluating the mechanical stability of
mechanical stability and debris generated by fretting and
the bore and cone interface of the head and stem junction of
fretting corrosion of the modular interface.
modular hip implants subjected to cyclic loading by measure-
2 1.5 The general concepts and methodologies described in
ments of fretting corrosion (1-5). Two test methods described
this practice could be applied to the study of other modular
are as follows:
interfaces in total joint prostheses.
1.1.1 Method I—The primary purpose of this method is to
1.6 This standard may involve hazardous materials, opera-
provide a uniform set of guidelines for long-term testing to
tions, and equipment. This standard does not purport to
determine the amount of damage by measurement of the
address all of the safety concerns, if any, associated with its
production of corrosion products and particulate debris from
use. It is the responsibility of the user of this standard to
fretting and fretting corrosion. Damage also is assessed by
establish appropriate safety and health practices and deter-
characterization of the damage to the bore and cone surfaces
mine the applicability of regulatory limitations prior to use.
(4, 5).
1.1.2 Methods II—This method provides for short-term
2. Referenced Documents
electrochemical evaluation of the fretting corrosion of the
2.1 ASTM Standards:
modular interface. It is not the intent of this method to produce
E4 Practices for Force Verification of Testing Machines
damage nor particulate debris but rather to provide a rapid
E466 Practice for Conducting Force Controlled Constant
method for qualitative assessment of design changes which do
Amplitude Axial Fatigue Tests of Metallic Materials
not include material changes (1-4).
E467 Practice for Verification of Constant Amplitude Dy-
1.2 This practice does not provide for judgment or predic-
namic Forces in an Axial Fatigue Testing System
tion of in vivo implant performance, but rather, provides for a
F561 Practice for Retrieval and Analysis of Medical De-
uniform set of guidelines for evaluating relative differences in
vices, and Associated Tissues and Fluids
performance between differing implant designs, constructs, or
F746 Test Method for Pitting or Crevice Corrosion of
materials with performance defined in the context of the
Metallic Surgical Implant Materials
amount of fretting and fretting corrosion. Also, this practice
F897 Test Method for Measuring Fretting Corrosion of
should permit direct comparison of fretting corrosion data
Osteosynthesis Plates and Screws
between independent research groups, and thus, provide for
F1440 Practice for Cyclic Fatigue Testing of Metallic
building of a data base on modular implant performance.
Stemmed Hip Arthroplasty Femoral Components Without
1.3 This practice provides for comparative testing of manu-
Torsion
factured hip femoral heads and stems and for coupon type
F1636 Specification for Bores and Cones for Modular
specimen testing where the male taper portion of the modular
Femoral Heads
junction does not include the entire hip implant, with the taper
G3 Practice for ConventionsApplicable to Electrochemical
portion of the coupon identical in design, manufacturing, and
Measurements in Corrosion Testing
materials to the taper of the final hip implant (4,5).
G5 Reference Test Method for Making Potentiostatic and
ThispracticeisunderthejurisdictionofASTMCommitteeF04onMedicaland
Surgical Materials and Devices and is the direct responsibility of Subcommittee For referenced ASTM standards, visit the ASTM website, www.astm.org, or
F04.15 on Material Test Methods. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Current edition approved Aug. 1, 2004. Published August 2004. Originally Standards volume information, refer to the standard’s Document Summary page on
approved in 1998. Last previous edition approved in 1998 as F1875 – 98. DOI: the ASTM website.
10.1520/F1875-98R04. Withdrawn.
2 5
The bold face numbers in parentheses refers to the list of references at the end Withdrawn. The last approved version of this historical standard is referenced
of this standard. on www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
F1875–98 (2004)
Potentiodynamic Anodic Polarization Measurements F1440. The head neck junction is exposed to a saline or
G15 Terminology Relating to Corrosion and Corrosion proteinaceous solution, either by immersion of the entire
Testing device, or with a fluid containing envelope. The cyclic load is
G40 Terminology Relating to Wear and Erosion applied for a minimum of 10 million cycles.At the conclusion
G61 Test Method for Conducting Cyclic Potentiodynamic of testing, the isolated fluid is withdrawn for chemical analysis
Polarization Measurements for Localized Corrosion Sus- for total elemental level, and characterization of particulate
ceptibility of Iron-, Nickel-, or Cobalt-Based Alloys debris. The taper interface is subsequently disengaged and the
G102 Practice for Calculation of Corrosion Rates and surfaces inspected for fretting wear and corrosion using optical
Related Information from Electrochemical Measurements microscopy and scanning electron microscopy. The output of
2.2 ISO Standards: thesemethodsisaquantitativemeasureoftotalelementallevel
ISO 7206-7 Endurance Performance of Stemmed Femoral andaqualitativeevaluationofdamageofthemodularinterface
Components Without Application of Torsion caused by fretting wear and corrosion.
4.2 Method II—A coupon similar to that used in Method I,
3. Terminology
or an entire femoral stem and head construct, may be mounted
in an inverted position in a test chamber. The chamber is filled
3.1 Definitions:
withanelectrolytesolutiontoalevelsufficienttosubmergethe
3.1.1 corrosive wear, n—wear in which chemical or elec-
bore and cone interface and a small portion of the exposed
trochemical reaction with the environment is significant.
neck. The area of contact and articulation between the ball and
3.1.2 coverage, n—the length, parallel to the taper surface,
the test apparatus is isolated from the electrolyte, either by
that the bore and cone interfaces are in contact.
being above the fill level, or with an elastomeric seal used to
3.1.3 crevice corrosion, n—localized corrosion of a metal
isolate the bottom of the test chamber.
surface at, or immediately adjacent to, an area that is shielded
4.2.1 Procedure A—A saturated calomel electrode with a
from full exposure to the environment because of close
luggin probe is used as a reference electrode to measure
proximity between the metal and the surface of another
changes in the corrosion potential with an electrometer. A
material.
counter electrode also may be employed and the polarization
3.1.4 external circuit, n—the wires, connectors, measuring
characteristics measured with a potentiostat.
devices, current sources, and so forth that are used to bring
4.2.2 Procedure B—A large surface area counter electrode
about or measure the desired electrical conditions within the
is immersed in the solution to simulate the area of the stem.A
test cell.
zero-resistance ammeter is connected between the test device
3.1.5 femoral head neck extension, n—a distance parallel to
and the counter electrode. The difference in current, thus
the taper axis, from the nominal neck offset length (k)as
defined in Specification F1636, and the center of the head. measured prior to and during cyclic loading, represents the
fretting corrosion current flowing between the modular inter-
Such variants from the nominal length are used to adjust for
resection level, leg length, and so forth. A positive neck face (anode) and the metal sheet (cathode).
extension equates to the center of the head being located
5. Significance and Use
further away from the stem.
5.1 The modular interfaces of total joint prostheses are
3.1.6 fretting, n—small amplitude oscillatory motion, usu-
subjected to micromotion that could result in fretting and
ally tangential, between two solid surfaces in contact.
corrosion. The release of corrosion products and particulate
3.1.7 fretting corrosion, n—the deterioration at the interface
debris could stimulate adverse biological reactions, as well as
between contacting surfaces as the result of corrosion and
lead to accelerated wear at the articulation interface. Methods
slight oscillatory slip between the two surfaces.
to assess the stability and corrosion resistance of the modular
3.1.8 fretting wear, n—wear arising as a result of fretting.
interfaces, therefore, are an essential component of device
3.1.9 total elemental level, n—thetotalweightofparticulate
testing.
matter and corrosion ions generated by fretting wear and
5.2 Long-term in vitro testing is essential to produce dam-
fretting corrosion. Most analytical techniques are unable to
age and debris from fretting of a modular interface (4,5). The
accurately differentiate between ions and particulates, and
useofproteinaceoussolutionsisrecommendedtobestsimulate
therefore, total elemental level refers to all matter and corro-
the in vivo environment.
sion products released by fretting wear and corrosion.
5.3 Short-term tests often can be useful in evaluations of
3.1.10 wear, n—damage to a solid surface, generally in-
differences in design during device development (1-4). The
volving progressive loss of material, due to relative motion
electrochemical methods provide semiquantitative measures of
between that surface and a contacting substance or substances.
fretting corrosion rates. The relative contributions of mechani-
4. Summary of Test Method cal and electrochemical processes to the total corrosion and
particulate release phenomena, however, have not been estab-
4.1 Method I—The femoral stem and head components, or
lished; therefore, these tests should not be utilized to compare
coupons to simulate head-taper-neck geometry, are loaded
the effects of changes in material combinations, but rather be
cyclically in a manner similar to that described in Practice
utilized to evaluate design changes of bore (head) and cone
(stem) components.
5.4 These tests are recommended for evaluating the fretting
Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
4th Floor, New York, NY 10036. wear and corrosion of modular interfaces of hip femoral head
F1875–98 (2004)
andstemcomponents.Similarmethodsmaybeappliedtoother
modular interfaces where fretting corrosion is of concern.
5.5 These methods are recommended for comparative
evaluation of the fretting wear and corrosion of new materials,
coatings, or designs, or a combination thereof, under consid-
eration for hip femoral head and neck modular interfaces.
Components for testing may be those of a manufactured
modular hip device (finished product) or sample coupons,
which are designed and manufactured for simulation of the
head, taper, and neck region of a modular hip device.
6. Apparatus
6.1 Testing Machines—The action of the machine should be
analyzed to ensure that the desired form and periodic force
amplitude is maintained for the duration of the test (see
Practice E467). The test machine should have a load monitor-
ing system, such as the transducer mounted in line with the
specimen. The loads should be monitored continuously in the
early stages of the test and periodically thereafter to ensure the
NOTE 1—The cathode sheet surrounds, but does not make contact with
desired load cycle is maintained. The varying load as deter-
the device being tested. For Procedure A, the counter electrode is not
minedbysuitabledynamicverificationshouldbemaintainedat
utilized, and is substituted with a luggin probe and calomel electrode.
all times to within 62 % of the maximum force being used in
FIG. 2 Suggested Set-Up for Method II Procedure B,
Measurements of Fretting Corrosion Currents of a Complete THR
accordance with Practices E4 and E466.
6.2 Specimen Mounting Devices, Method I—Modular hip
and stem components shall be set-up as described in Practices
leakage), throughout the course of testing. The volume of the
F1440.Couponsamplesshallbeset-upasshowninFig.1.The
chamber shall be between 5 and 100 mL.
set-up must provide for identical loading geometry as that in
NOTE 1—The use of small fluid volumes with the sleeve containment
Practice F1440.
method may not produce as much fretting corrosion as full prosthesis
6.3 Specimen Mounting Devices, Method II—Modular hip
exposure, due to the reduced surface area of the cathodic metal exposed.
and stem components shall be set-up in an inverted position, as
6.5 Environmental Chamber, Method II—Thechambershall
shown in Fig. 2. Coupon samples may be set up as shown in
be filled with electrolyte so as to submerge the modular
Fig. 1, or in an inverted orientation.
interface.An elastomeric seal is used to isolate the contact area
6.4 Environmental Containment, Method I—The prosthesis
between the head and the load application surface. Similar
may be placed in an environmental chamber, which is filled
seals should be employed for coupon sample testing. For
with the appropriate fluid. Care should be taken to ensure that
coupons orientated shown in Fig. 1, the chamber fill level shall
the contact area between the head and the low friction thrust
bekeptbelowthearticulationbetweentheheadandtheloading
bearing is not exposed to the electrolyte solution. The modular
apparatus.
interface of the prostheses or coupon samples also may be
6.6 Counter and Reference Electrodes, Method II—A
enclosed in an elastomeric sleeve, which contains the electro-
counter electrode is included in the external circuit of Method
lyte. The materials used for such isolation must be nonreactive
II to act as a cathode for measurement of corrosion currents.A
and capable of retaining the fluid environment, (that is, prevent
reference electrode is employed for measuremen
...
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