ASTM F1672-14(2019)
(Specification)Standard Specification for Resurfacing Patellar Prosthesis (Withdrawn 2023)
Standard Specification for Resurfacing Patellar Prosthesis (Withdrawn 2023)
ABSTRACT
This specification covers the basic material descriptions, device geometry (axisymmetric and nonsymmetric), and in-vivo performance characteristics of patellar resurfacing prosthetic devices used to provide a functioning articulation between the bones of the patella and the femur. This specification does not cover the details for quality assurance, design control, and production control contained in 21 CFR 820 and ISO 9001. All devices conforming to this specification shall be fabricated from materials with adequate mechanical strength and durability, corrosion resistance, and biocompatibility. In the evaluation of their safety and efficacy, patella prosthesis shall adhere to the minimum acceptance criteria specified for the following failure modes: dislocation or laterial subluxation; component disassociation; fixation failure; device fracture; and articular surface wear.
SCOPE
1.1 This specification covers patellar resurfacing devices used to provide a functioning articulation between the patella and the femur.
1.2 This specification is intended to provide basic descriptions of material and device geometry. Additionally, those characteristics determined to be important to in-vivo performance of the device are defined.
1.3 This specification does not cover the details for quality assurance, design control, and production control contained in 21 CFR 820 and ISO 9001.
Note 1: Devices for custom applications are not covered by this specification.
1.4 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.
WITHDRAWN RATIONALE
This specification covered patellar resurfacing devices used to provide a functioning articulation between the patella and the femur.
Formerly under the jurisdiction of Committee F04 on Medical and Surgical Materials and Devices, this specification was withdrawn in December 2023. This standard is being withdrawn without replacement due to its limited use by industry.
General Information
Relations
Buy Standard
Standards Content (Sample)
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.
Designation:F1672 −14 (Reapproved 2019)
Standard Specification for
Resurfacing Patellar Prosthesis
This standard is issued under the fixed designation F1672; 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 F138 Specification for Wrought 18Chromium-14Nickel-
2.5Molybdenum Stainless Steel Bar andWire for Surgical
1.1 This specification covers patellar resurfacing devices
Implants (UNS S31673)
used to provide a functioning articulation between the patella
F451 Specification for Acrylic Bone Cement
and the femur.
F562 Specification for Wrought 35Cobalt-35Nickel-
1.2 This specification is intended to provide basic descrip-
20Chromium-10Molybdenum Alloy for Surgical Implant
tions of material and device geometry. Additionally, those
Applications (UNS R30035)
characteristics determined to be important to in-vivo perfor-
F563 Specification for Wrought Cobalt-20Nickel-
mance of the device are defined.
20Chromium-3.5Molybdenum-3.5Tungsten-5Iron Alloy
for Surgical Implant Applications (UNS R30563) (With-
1.3 This specification does not cover the details for quality
assurance, design control, and production control contained in drawn 2005)
F603 Specification for High-Purity Dense Aluminum Oxide
21 CFR 820 and ISO 9001.
for Medical Application
NOTE 1—Devices for custom applications are not covered by this
F648 Specification for Ultra-High-Molecular-Weight Poly-
specification.
ethylene Powder and Fabricated Form for Surgical Im-
1.4 This international standard was developed in accor-
plants
dance with internationally recognized principles on standard-
F732 Test Method for Wear Testing of Polymeric Materials
ization established in the Decision on Principles for the
Used in Total Joint Prostheses
Development of International Standards, Guides and Recom-
F745 Specification for 18Chromium-12.5Nickel-
mendations issued by the World Trade Organization Technical
2.5Molybdenum Stainless Steel for Cast and Solution-
Barriers to Trade (TBT) Committee.
Annealed Surgical Implant Applications (Withdrawn
2012)
2. Referenced Documents
F746 Test Method for Pitting or Crevice Corrosion of
2.1 ASTM Standards:
Metallic Surgical Implant Materials
F75 Specification for Cobalt-28 Chromium-6 Molybdenum
F748 PracticeforSelectingGenericBiologicalTestMethods
Alloy Castings and Casting Alloy for Surgical Implants
for Materials and Devices
(UNS R30075)
F799 Specification for Cobalt-28 Chromium-6 Molybdenum
F86 Practice for Surface Preparation and Marking of Metal-
Alloy Forgings for Surgical Implants (UNS R31537,
lic Surgical Implants
R31538, R31539)
F90 Specification for Wrought Cobalt-20Chromium-
F981 Practice for Assessment of Compatibility of Biomate-
15Tungsten-10NickelAlloy for Surgical ImplantApplica-
rials for Surgical Implants with Respect to Effect of
tions (UNS R30605)
Materials on Muscle and Insertion into Bone
F136 Specification for Wrought Titanium-6Aluminum-
F983 Practice for Permanent Marking of Orthopaedic Im-
4Vanadium ELI (Extra Low Interstitial)Alloy for Surgical
plant Components
Implant Applications (UNS R56401)
F1044 Test Method for Shear Testing of Calcium Phosphate
Coatings and Metallic Coatings
F1108 Specification for Titanium-6Aluminum-4Vanadium
This specification is under the jurisdiction of ASTM Committee F04 on
Medical and Surgical Materials and Devices and is under the direct responsibility of Alloy Castings for Surgical Implants (UNS R56406)
Subcommittee F04.22 on Arthroplasty.
F1147 Test Method for Tension Testing of Calcium Phos-
Current edition approved Aug. 15, 2019. Published August 2019. Originally
phate and Metallic Coatings
approved in 1995. Last previous edition approved in 2014 as F1672 – 14. DOI:
F1160 Test Method for Shear and Bending Fatigue Testing
10.1520/F1672-14R19.
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
Standards volume information, refer to the standard’s Document Summary page on The last approved version of this historical standard is referenced on
the ASTM website. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F1672−14 (2019)
of Calcium Phosphate and Metallic Medical and Compos- 3.1.4 Discussion—The dimension T is shown in Fig. 1 and
ite Calcium Phosphate/Metallic Coatings Fig. 2 to be the distance from a surface contact point to an
internal peg or an edge of the metal back.The exact location of
2.2 Government Document:
the minimum thickness at risk may be at a different site and
21 CFR 820 Good Manufacturing Practice for Medical
will depend on the design of the patella prosthesis and the
Devices
mating femoral component. For devices manufactured from a
2.3 ISO Standard:
single material, T should be measured from the wear surface
ISO 9001 Quality Management Systems - Requirements 3
to the back of the fixation surface.
3. Terminology
3.1.5 W —maximummedial-lateralwidthofthearticulating
3.1 Definitions—Dimensions defined as follows are mea- surface in the frontal plane.
sured in whole or in part in the sagittal, transverse, and coronal
3.1.6 W —maximum medial-lateral width of the metal back
(or frontal) planes as appropriate. See Fig. 1 and Fig. 2.
in the frontal plane.
3.1.7 H —articulating surface superior-inferior height in the
frontal plane.
3.1.8 H —metal back superior-inferior height in the frontal
plane.
3.1.9 Rc—radius of curvature for single radius axisymmet-
ric domes only.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 dome—a style of axisymmetrical prosthesis that has a
single uniform radius of curvature (that is, button).
3.2.2 fixation element—any peg, keel, or other protrusion
from the nonarticulating side of the patellar component in-
(a) (b) (c)
tended to increase the surface contact or mechanical interlock
NOTE 1—Figure 1(a) and (b) show a dome style and Fig. 1(c) shows a between the component, the bonding agent (bone cement) or
sombrero style.
the natural patella, or both.
FIG. 1Two Versions of Axisymmetric Patella Prostheses
3.2.3 marker wire—a nonstructural, generally thin metallic
wire, designed to be apparent on X-rays taken after placement
of implants that otherwise would not be apparent on such
X-rays.
3.2.4 metal back—a metal structure supporting the articu-
lating surface material. This may be fixed rigidly to the
articulating surface or it may be fixed such that it allows the
articulating surface to rotate or translate.
(a) Transverse Cross Section With (b) Sagittal Cross Section
Lateral to the Right 3.2.5 radii of curvature—the geometry of the articular
surface may be described by a list of appropriate radii of
FIG. 2 Example of a Nonsymmetric Patella Prosthesis
curvature.
3.2.6 sombrero—a style of axisymmetric prosthesis that has
3.1.1 T —total overall prosthetic thickness, for example,
multiple radii of curvature. (See Fig. 1(c).)
from the apex of the dome to the free end of pegs or other
fixation geometry.
4. Classification
3.1.2 T —thickness of the patellar prosthesis from the plane
4.1 Patellar replacement devices may be classified accord-
of the bone-prosthesis interface (excluding pegs, keels, and so
ing to geometry:
forth) to the apex of the articulating surface.
4.1.1 Axisymmetric—The articulating surface is symmetric
3.1.3 T —minimum polymer thickness of the patellar pros-
on an axis perpendicular to the prepared bonding surface (for
thesis in direct contact with the femoral component that is “at
example, Dome patellas and sombrero-type patellas). See Fig.
risk” for wear; this is measured perpendicular to the tangent of
1.
the wear surface at the point of contact with the femoral
4.1.2 Nonsymmetric—The articulating surface is not axi-
component.
symmetric but may be symmetric on a plane. Examples of this
type are anatomical or oblong prosthesis. See Fig. 2.
Available from U.S. Government Printing Office, Superintendent of
4.2 It is important to define the type of fixation geometry so
Documents, 732 N. Capitol St., NW, Washington, DC 20401-0001, http://
that the user can understand the degree of bone invasion:
www.access.gpo.gov.
4.2.1 Peg—Number, size (for example: length, width,
Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
4th Floor, New York, NY 10036, http://www.ansi.org. diameter, and so forth), and location, and
F1672−14 (2019)
4.2.2 Keel—Width, length, thickness, geometry, and loca- articular surface with subsequent metal-on-metal wear debris.
tion. Thin UHMWPE may accelerate this wear but it is design-
dependent.
5. Materials and Manufacture
6.3 The failure modes may be addressed through relevant
5.1 The choice of materials is understood to be a necessary
testing (for example, shear testing of device component inter-
but not sufficient assurance of function of the device made
faces) and analysis (for example, stress analysis due to loading
fromthem.Alldevicesconformingtothisspecificationshallbe
in accordance with 6.3.1). The testing may encompass some
fabricated from materials with adequate mechanical strength
combination of static and dynamic loading environments.
and durability, corrosion resistance and biocompatibility.
6.3.1 Contactareaandcontactpressuredistributionsmaybe
5.1.1 Mechanical Strength—Components of various pros-
determined at various flexion angles using one of several
theses have been successfully fabricated from materials in the
published methods (9-14) to provide a representation of
following Specifications: F75, F90, F136, F138, F562, F563,
stresses applied to the bearing surfaces and to the components.
F603, F648, F745, F799, and F1108. The articulating surface
Fig. 3 shows a possible test set-up configuration. The position
should be fabricated from a material such as UHMWPE in
of the patella component in relation to the femoral component
accordance with Specification F648.
should be defined as a result of biomechanical analysis.
5.1.2 Corrosion Resistance—Materials with limited or no
Flexion angles of 15, 45, and 90° with corresponding loads of
history of successful use for orthopedic implant application
377, 961, and 2195 N, respectively, are recommended (15-19).
shall exhibit corrosion resistance equal to or better than one of
If the prosthesis is designed to function at higher flexion
the materials listed in 5.1.1 when tested in accordance with
angles, then these measurements should also be made at the
Test Method F746.
maximum flexion angle and the corresponding loading condi-
5.1.3 Biocompatibility—Materialswithlimitedor no history
tions justified. If these tests are performed, it is important to
of successful use for orthopedic implant application shall
maintain consistent test parameters and to evaluate other
exhibitanacceptablebiologicalresponseequaltoorbetterthan
prostheses under the same conditions.
one of the materials listed in 5.1.1 when tested in accordance
6.4 Polymeric components as manufactured shall be made
with Practices F748 and F981.
from materials demonstrating wear rates substantially equiva-
lent to or less than UHMWPE as determined by Test Method
6. Performance Requirements
F732.
6.1 The implant shall be capable of withstanding sustained
NOTE 2—In situations where the pin-on-flat test may not be considered
static and dynamic physiologic loads without compromise of
appropriate, other test methods may be considered.
its function for the intended use and environment. Device
testing shall be done in keeping with the implant’s intended 6.5 Porous metal coatings shall be tested according to Test
function.
MethodF1044(shearstrength)andTestMethodF1147(tensile
strength) and the coating strength for each test should exceed
6.2 Therearerelevantfailuremodeslistedasfollowswhich,
20MPa.Thefatiguepropertiesmaybeevaluatedinaccordance
at a minimum, shall be considered in the evaluation of the
with Test Method F1160.
safety and efficacy of a patella prosthesis. Literature references
(1-8) have been included in the rationale statement in support
7. Dimensions, Mass, and Permissible Variations
of these failure modes.
7.1 Dimensions of patellar resurfacing devices shall be as
6.2.1 Dislocation or Lateral Subluxation (Over the Lateral
designated,butnotlimitedtothosedescribed,inFig.1andFig.
Portion of the Femoral Articular Surface)—This has occurred
2. The tolerance and methods of dimensional measurement
in the past and is design and patient specific.
6.2.2 Component Disassociation—Devices made from mul-
tiple layers or components have disassociated under clinical
use (for example, the articulating surface from the metal back,
the porous coating from the metal back, and so forth). This
disassociation may be evaluated through shear loading or
compression loading, or a combination of the two.
6.2.3 Fixation Failure—Devices have loosened at the inter-
face with bone. Attachment mechanisms such as pegs have
sheared or failed. Components have become loose within the
bone cement.
6.2.4 Device Fracture—Partial or complete fracture of ei-
ther the articular surface or the metal back.
6.2.5 Articular Surface Wear—Patellar prostheses have
failed due to excessive wear of the articulating surface result-
ing in polymer debris and in some cases “wear through” of the
The boldface numbers given in parentheses refer to a list of references at the FIG. 3Test Configuration for Contact Area and Contact Stress
end of the text. Measurements
F1672−14 (2019)
shall conform with industry practice and, whenever possible, 8.5 Ifoneofthecomponentsisnotradiographicallyopaque,
on an international basis. it may be appropriately marked for radiographic evaluation.
The marker wire is a noncritical element and may not be
8. Finish and Product Marking necessary. If a marker wire is used it should be placed in a
noncriticalareatoavoiddegradingthestructuralandfunctional
8.1 Items conforming to this specification shall be finished
properties of the device.
in accordance with Practice F86, where applicable.
9. Packaging and Package Marking
8.2 Polymeric Bearing Surface Finish—The polymeric
bearing surface finish shall conform to the manufacturer’s
9.1 Adequate dimensioning to describe overall size and
documentedstandardsconcerningconcentricity,sphericity,and
shape (see Fig. 1 and Fig. 2 for examples)
...
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: F1672 − 14 (Reapproved 2019)
Standard Specification for
Resurfacing Patellar Prosthesis
This standard is issued under the fixed designation F1672; 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 F138 Specification for Wrought 18Chromium-14Nickel-
2.5Molybdenum Stainless Steel Bar and Wire for Surgical
1.1 This specification covers patellar resurfacing devices
Implants (UNS S31673)
used to provide a functioning articulation between the patella
F451 Specification for Acrylic Bone Cement
and the femur.
F562 Specification for Wrought 35Cobalt-35Nickel-
1.2 This specification is intended to provide basic descrip-
20Chromium-10Molybdenum Alloy for Surgical Implant
tions of material and device geometry. Additionally, those
Applications (UNS R30035)
characteristics determined to be important to in-vivo perfor-
F563 Specification for Wrought Cobalt-20Nickel-
mance of the device are defined.
20Chromium-3.5Molybdenum-3.5Tungsten-5Iron Alloy
1.3 This specification does not cover the details for quality for Surgical Implant Applications (UNS R30563) (With-
drawn 2005)
assurance, design control, and production control contained in
21 CFR 820 and ISO 9001. F603 Specification for High-Purity Dense Aluminum Oxide
for Medical Application
NOTE 1—Devices for custom applications are not covered by this
F648 Specification for Ultra-High-Molecular-Weight Poly-
specification.
ethylene Powder and Fabricated Form for Surgical Im-
1.4 This international standard was developed in accor-
plants
dance with internationally recognized principles on standard-
F732 Test Method for Wear Testing of Polymeric Materials
ization established in the Decision on Principles for the
Used in Total Joint Prostheses
Development of International Standards, Guides and Recom-
F745 Specification for 18Chromium-12.5Nickel-
mendations issued by the World Trade Organization Technical
2.5Molybdenum Stainless Steel for Cast and Solution-
Barriers to Trade (TBT) Committee.
Annealed Surgical Implant Applications (Withdrawn
2012)
2. Referenced Documents
F746 Test Method for Pitting or Crevice Corrosion of
2.1 ASTM Standards:
Metallic Surgical Implant Materials
F75 Specification for Cobalt-28 Chromium-6 Molybdenum
F748 Practice for Selecting Generic Biological Test Methods
Alloy Castings and Casting Alloy for Surgical Implants
for Materials and Devices
(UNS R30075)
F799 Specification for Cobalt-28 Chromium-6 Molybdenum
F86 Practice for Surface Preparation and Marking of Metal-
Alloy Forgings for Surgical Implants (UNS R31537,
lic Surgical Implants
R31538, R31539)
F90 Specification for Wrought Cobalt-20Chromium-
F981 Practice for Assessment of Compatibility of Biomate-
15Tungsten-10Nickel Alloy for Surgical Implant Applica-
rials for Surgical Implants with Respect to Effect of
tions (UNS R30605)
Materials on Muscle and Insertion into Bone
F136 Specification for Wrought Titanium-6Aluminum-
F983 Practice for Permanent Marking of Orthopaedic Im-
4Vanadium ELI (Extra Low Interstitial) Alloy for Surgical
plant Components
Implant Applications (UNS R56401)
F1044 Test Method for Shear Testing of Calcium Phosphate
Coatings and Metallic Coatings
1 F1108 Specification for Titanium-6Aluminum-4Vanadium
This specification is under the jurisdiction of ASTM Committee F04 on
Alloy Castings for Surgical Implants (UNS R56406)
Medical and Surgical Materials and Devices and is under the direct responsibility of
Subcommittee F04.22 on Arthroplasty.
F1147 Test Method for Tension Testing of Calcium Phos-
Current edition approved Aug. 15, 2019. Published August 2019. Originally
phate and Metallic Coatings
approved in 1995. Last previous edition approved in 2014 as F1672 – 14. DOI:
F1160 Test Method for Shear and Bending Fatigue Testing
10.1520/F1672-14R19.
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
Standards volume information, refer to the standard’s Document Summary page on The last approved version of this historical standard is referenced on
the ASTM website. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F1672 − 14 (2019)
of Calcium Phosphate and Metallic Medical and Compos- 3.1.4 Discussion—The dimension T is shown in Fig. 1 and
ite Calcium Phosphate/Metallic Coatings Fig. 2 to be the distance from a surface contact point to an
internal peg or an edge of the metal back. The exact location of
2.2 Government Document:
the minimum thickness at risk may be at a different site and
21 CFR 820 Good Manufacturing Practice for Medical
will depend on the design of the patella prosthesis and the
Devices
mating femoral component. For devices manufactured from a
2.3 ISO Standard:
single material, T should be measured from the wear surface
ISO 9001 Quality Management Systems - Requirements
to the back of the fixation surface.
3. Terminology
3.1.5 W —maximum medial-lateral width of the articulating
3.1 Definitions—Dimensions defined as follows are mea-
surface in the frontal plane.
sured in whole or in part in the sagittal, transverse, and coronal
3.1.6 W —maximum medial-lateral width of the metal back
(or frontal) planes as appropriate. See Fig. 1 and Fig. 2.
in the frontal plane.
3.1.7 H —articulating surface superior-inferior height in the
frontal plane.
3.1.8 H —metal back superior-inferior height in the frontal
plane.
3.1.9 Rc—radius of curvature for single radius axisymmet-
ric domes only.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 dome—a style of axisymmetrical prosthesis that has a
single uniform radius of curvature (that is, button).
3.2.2 fixation element—any peg, keel, or other protrusion
from the nonarticulating side of the patellar component in-
(a) (b) (c)
tended to increase the surface contact or mechanical interlock
NOTE 1—Figure 1(a) and (b) show a dome style and Fig. 1(c) shows a between the component, the bonding agent (bone cement) or
sombrero style.
the natural patella, or both.
FIG. 1 Two Versions of Axisymmetric Patella Prostheses
3.2.3 marker wire—a nonstructural, generally thin metallic
wire, designed to be apparent on X-rays taken after placement
of implants that otherwise would not be apparent on such
X-rays.
3.2.4 metal back—a metal structure supporting the articu-
lating surface material. This may be fixed rigidly to the
articulating surface or it may be fixed such that it allows the
articulating surface to rotate or translate.
(a) Transverse Cross Section With (b) Sagittal Cross Section
Lateral to the Right 3.2.5 radii of curvature—the geometry of the articular
surface may be described by a list of appropriate radii of
FIG. 2 Example of a Nonsymmetric Patella Prosthesis
curvature.
3.2.6 sombrero—a style of axisymmetric prosthesis that has
3.1.1 T —total overall prosthetic thickness, for example,
1 multiple radii of curvature. (See Fig. 1(c).)
from the apex of the dome to the free end of pegs or other
fixation geometry.
4. Classification
3.1.2 T —thickness of the patellar prosthesis from the plane
4.1 Patellar replacement devices may be classified accord-
of the bone-prosthesis interface (excluding pegs, keels, and so
ing to geometry:
forth) to the apex of the articulating surface.
4.1.1 Axisymmetric—The articulating surface is symmetric
3.1.3 T —minimum polymer thickness of the patellar pros-
3 on an axis perpendicular to the prepared bonding surface (for
thesis in direct contact with the femoral component that is “at
example, Dome patellas and sombrero-type patellas). See Fig.
risk” for wear; this is measured perpendicular to the tangent of
1.
the wear surface at the point of contact with the femoral
4.1.2 Nonsymmetric—The articulating surface is not axi-
component.
symmetric but may be symmetric on a plane. Examples of this
type are anatomical or oblong prosthesis. See Fig. 2.
Available from U.S. Government Printing Office, Superintendent of 4.2 It is important to define the type of fixation geometry so
Documents, 732 N. Capitol St., NW, Washington, DC 20401-0001, http://
that the user can understand the degree of bone invasion:
www.access.gpo.gov.
5 4.2.1 Peg—Number, size (for example: length, width,
Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
4th Floor, New York, NY 10036, http://www.ansi.org. diameter, and so forth), and location, and
F1672 − 14 (2019)
4.2.2 Keel—Width, length, thickness, geometry, and loca- articular surface with subsequent metal-on-metal wear debris.
tion. Thin UHMWPE may accelerate this wear but it is design-
dependent.
5. Materials and Manufacture
6.3 The failure modes may be addressed through relevant
5.1 The choice of materials is understood to be a necessary
testing (for example, shear testing of device component inter-
but not sufficient assurance of function of the device made
faces) and analysis (for example, stress analysis due to loading
from them. All devices conforming to this specification shall be
in accordance with 6.3.1). The testing may encompass some
fabricated from materials with adequate mechanical strength
combination of static and dynamic loading environments.
and durability, corrosion resistance and biocompatibility.
6.3.1 Contact area and contact pressure distributions may be
5.1.1 Mechanical Strength—Components of various pros-
determined at various flexion angles using one of several
theses have been successfully fabricated from materials in the
published methods (9-14) to provide a representation of
following Specifications: F75, F90, F136, F138, F562, F563,
stresses applied to the bearing surfaces and to the components.
F603, F648, F745, F799, and F1108. The articulating surface
Fig. 3 shows a possible test set-up configuration. The position
should be fabricated from a material such as UHMWPE in
of the patella component in relation to the femoral component
accordance with Specification F648.
should be defined as a result of biomechanical analysis.
5.1.2 Corrosion Resistance—Materials with limited or no
Flexion angles of 15, 45, and 90° with corresponding loads of
history of successful use for orthopedic implant application
377, 961, and 2195 N, respectively, are recommended (15-19).
shall exhibit corrosion resistance equal to or better than one of
If the prosthesis is designed to function at higher flexion
the materials listed in 5.1.1 when tested in accordance with
angles, then these measurements should also be made at the
Test Method F746.
maximum flexion angle and the corresponding loading condi-
5.1.3 Biocompatibility—Materials with limited or no history
tions justified. If these tests are performed, it is important to
of successful use for orthopedic implant application shall
maintain consistent test parameters and to evaluate other
exhibit an acceptable biological response equal to or better than
prostheses under the same conditions.
one of the materials listed in 5.1.1 when tested in accordance
6.4 Polymeric components as manufactured shall be made
with Practices F748 and F981.
from materials demonstrating wear rates substantially equiva-
lent to or less than UHMWPE as determined by Test Method
6. Performance Requirements
F732.
6.1 The implant shall be capable of withstanding sustained
static and dynamic physiologic loads without compromise of NOTE 2—In situations where the pin-on-flat test may not be considered
appropriate, other test methods may be considered.
its function for the intended use and environment. Device
testing shall be done in keeping with the implant’s intended
6.5 Porous metal coatings shall be tested according to Test
function. Method F1044 (shear strength) and Test Method F1147 (tensile
strength) and the coating strength for each test should exceed
6.2 There are relevant failure modes listed as follows which,
20 MPa. The fatigue properties may be evaluated in accordance
at a minimum, shall be considered in the evaluation of the
with Test Method F1160.
safety and efficacy of a patella prosthesis. Literature references
(1-8) have been included in the rationale statement in support
7. Dimensions, Mass, and Permissible Variations
of these failure modes.
7.1 Dimensions of patellar resurfacing devices shall be as
6.2.1 Dislocation or Lateral Subluxation (Over the Lateral
designated, but not limited to those described, in Fig. 1 and Fig.
Portion of the Femoral Articular Surface)—This has occurred
2. The tolerance and methods of dimensional measurement
in the past and is design and patient specific.
6.2.2 Component Disassociation—Devices made from mul-
tiple layers or components have disassociated under clinical
use (for example, the articulating surface from the metal back,
the porous coating from the metal back, and so forth). This
disassociation may be evaluated through shear loading or
compression loading, or a combination of the two.
6.2.3 Fixation Failure—Devices have loosened at the inter-
face with bone. Attachment mechanisms such as pegs have
sheared or failed. Components have become loose within the
bone cement.
6.2.4 Device Fracture—Partial or complete fracture of ei-
ther the articular surface or the metal back.
6.2.5 Articular Surface Wear—Patellar prostheses have
failed due to excessive wear of the articulating surface result-
ing in polymer debris and in some cases “wear through” of the
FIG. 3 Test Configuration for Contact Area and Contact Stress
The boldface numbers given in parentheses refer to a list of references at the
end of the text. Measurements
F1672 − 14 (2019)
shall conform with industry practice and, whenever possible, 8.5 If one of the components is not radiographically opaque,
on an international basis. it may be appropriately marked for radiographic evaluation.
The marker wire is a noncritical element and may not be
necessary. If a marker wire is used it should be placed in a
8. Finish and Product Marking
noncritical area to avoid degrading the structural and functional
8.1 Items conforming to this specification shall be finished
properties of the device.
in accordance with Practice F86, where applicable.
8.2 Polymeric Bearing Surface Finish—The polymeric 9. Packaging and Package Marking
bearing surface finish shall conform to the manufacturer’s
9.1 Adequate dimensioning to describe overall size and
documented standards concerning concentricity, sphericity, and
shape (see Fig. 1 and Fig. 2 for exampl
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.