ASTM F1672-95(2011)
(Specification)Standard Specification for Resurfacing Patellar Prosthesis
Standard Specification for Resurfacing Patellar Prosthesis
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.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:F1672 −95(Reapproved 2011)
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 Applications (UNS R30035)
F563 Specification for Wrought Cobalt-20Nickel-
1.1 This specification covers patellar resurfacing devices
20Chromium-3.5Molybdenum-3.5Tungsten-5Iron Alloy
used to provide a functioning articulation between the patella
for Surgical Implant Applications (UNS R30563) (With-
and the femur.
drawn 2005)
1.2 This specification is intended to provide basic descrip-
F603 Specification for High-Purity Dense Aluminum Oxide
tions of material and device geometry. Additionally, those
for Medical Application
characteristics determined to be important to in-vivo perfor-
F648 Specification for Ultra-High-Molecular-Weight Poly-
mance of the device are defined.
ethylene Powder and Fabricated Form for Surgical Im-
1.3 This specification does not cover the details for quality
plants
assurance, design control, and production control contained in
F732 Test Method for Wear Testing of Polymeric Materials
21 CFR 820 and ISO 9001.
Used in Total Joint Prostheses
NOTE 1—Devices for custom applications are not covered by this F745 Specification for 18Chromium-12.5Nickel-
specification.
2.5Molybdenum Stainless Steel for Cast and Solution-
Annealed Surgical Implant Applications (Withdrawn
2. Referenced Documents
2012)
2.1 ASTM Standards:
F746 Test Method for Pitting or Crevice Corrosion of
F75 Specification for Cobalt-28 Chromium-6 Molybdenum
Metallic Surgical Implant Materials
Alloy Castings and Casting Alloy for Surgical Implants
F748 PracticeforSelectingGenericBiologicalTestMethods
(UNS R30075)
for Materials and Devices
F86 Practice for Surface Preparation and Marking of Metal-
F799 Specification for Cobalt-28Chromium-6Molybdenum
lic Surgical Implants
Alloy Forgings for Surgical Implants (UNS R31537,
F90 Specification for Wrought Cobalt-20Chromium-
R31538, R31539)
15Tungsten-10NickelAlloy for Surgical ImplantApplica-
F981 Practice for Assessment of Compatibility of Biomate-
tions (UNS R30605)
rials for Surgical Implants with Respect to Effect of
F136 Specification for Wrought Titanium-6Aluminum-
Materials on Muscle and Bone
4Vanadium ELI (Extra Low Interstitial)Alloy for Surgical
F983 Practice for Permanent Marking of Orthopaedic Im-
Implant Applications (UNS R56401)
plant Components
F138 Specification for Wrought 18Chromium-14Nickel-
F1044 Test Method for Shear Testing of Calcium Phosphate
2.5Molybdenum Stainless Steel Bar andWire for Surgical
Coatings and Metallic Coatings
Implants (UNS S31673)
F1108 Specification for Titanium-6Aluminum-4Vanadium
F451 Specification for Acrylic Bone Cement
Alloy Castings for Surgical Implants (UNS R56406)
F562 Specification for Wrought 35Cobalt-35Nickel-
F1147 Test Method for Tension Testing of Calcium Phos-
20Chromium-10Molybdenum Alloy for Surgical Implant
phate and Metallic Coatings
2.2 Government Document:
This specification is under the jurisdiction of ASTM Committee F04 on
21 CFR 820 Good Manufacturing Practice for Medical
Medical and Surgical Materials and Devices and is under the direct responsibility of
Devices
Subcommittee F04.22 on Arthroplasty.
Current edition approved March 1, 2011. Published April 2011. Originally
approved in 1995. Last previous edition approved in 2005 as F1672 – 95 (2005).
DOI: 10.1520/F1672-95R11.
2 3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or The last approved version of this historical standard is referenced on
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM www.astm.org.
Standards volume information, refer to the standard’s Document Summary page on Available from Superintendent of Documents, U.S. Government Printing
the ASTM website. Office, Washington, DC 20402.
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F1672−95 (2011)
2.3 ISO Standard: 3.1.5 W —maximummedial-lateralwidthofthearticulating
ISO 9001 Quality Systems Model for Quality Assurance in surface in the frontal plane.
Design/Development, Production, Installation, and Ser-
3.1.6 W —maximum medial-lateral width of the metal back
vicing
in the frontal plane.
3.1.7 H —articulating surface superior-inferior height in the
3. Terminology 1
frontal plane.
3.1 Definitions—Dimensions defined as follows are mea-
3.1.8 H —metal back superior-inferior height in the frontal
sured in whole or in part in the sagittal, transverse, and coronal
plane.
(or frontal) planes as appropriate. See Fig. 1 and Fig. 2.
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-
tended to increase the surface contact or mechanical interlock
between the component, the bonding agent (bone cement) or
the natural patella, or both.
(a) (b) (c)
3.2.3 marker wire—a nonstructural, generally thin metallic
wire, designed to be apparent on X-rays taken after placement
NOTE 1—Figure 1(a) and (b) show a dome style and Fig. 1(c) shows a
of implants that otherwise would not be apparent on such
sombrero style.
X-rays.
FIG. 1Two Versions of Axisymmetric Patella Prostheses
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.
3.2.5 radii of curvature—the geometry of the articular
surface may be described by a list of appropriate radii of
curvature.
(a) Transverse Cross Section With (b) Sagittal Cross Section
3.2.6 sombrero—a style of axisymmetric prosthesis that has
Lateral to the Right
multiple radii of curvature. (SeeFig. 1c.)
FIG. 2 Example of a Nonsymmetric Patella Prosthesis
4. Classification
3.1.1 T — total overall prosthetic thickness, for example,
1 4.1 Patellar replacement devices may be classified accord-
from the apex of the dome to the free end of pegs or other
ing to geometry:
fixation geometry.
4.1.1 Axisymmetric— The articulating surface is symmetric
on an axis perpendicular to the prepared bonding surface (for
3.1.2 T —thicknessofthepatellarprosthesisfromtheplane
example, Dome patellas and sombrero-type patellas). See Fig.
of the bone-prosthesis interface (excluding pegs, keels, and so
1.
forth) to the apex of the articulating surface.
4.1.2 Nonsymmetric— The articulating surface is not axi-
3.1.3 T — minimum polymer thickness of the patellar
symmetric but may be symmetric on a plane. Examples of this
prosthesis in direct contact with the femoral component that is
type are anatomical or oblong prosthesis. See Fig. 2.
“atrisk”forwear;thisismeasuredperpendiculartothetangent
of the wear surface at the point of contact with the femoral
4.2 It is important to define the type of fixation geometry so
component. that the user can understand the degree of bone invasion:
4.2.1 Peg—Number, size (for example: length, width,
3.1.4 Discussion—The dimension T is shown in Fig. 1 and
diameter, and so forth), and location and
Fig. 2 to be the distance from a surface contact point to an
4.2.2 Keel—Width, length, thickness, geometry, and loca-
internal peg or an edge of the metal back.The exact location of
tion.
the minimum thickness at risk may be at a different site and
will depend on the design of the patella prosthesis and the
5. Materials and Manufacture
mating femoral component. For devices manufactured from a
single material, T should be measured from the wear surface
3 5.1 The choice of materials is understood to be a necessary
to the back of the fixation surface.
but not sufficient assurance of function of the device made
fromthem.Alldevicesconformingtothisspecificationshallbe
fabricated from materials with adequate mechanical strength
Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
4th Floor, New York, NY 10036. and durability, corrosion resistance and biocompatibility.
F1672−95 (2011)
5.1.1 Mechanical Strength—Components of various pros- 6.3 The failure modes may be addressed through relevant
theses have been successfully fabricated from materials in the testing (for example, shear testing of device component inter-
following Specifications: F75, F90, F136, F138, F562, F563, faces) and analysis (for example, analysis of internal stress due
F603, F648, F745, F799, and F1108. The articulating surface to loading). The testing may encompass some combination of
should be fabricated from a material such as UHMWPE in static and dynamic loading environments.
accordance with Specification F648.
6.4 Polymeric components as manufactured shall be made
5.1.2 Corrosion Resistance—Materials with limited or no
from materials demonstrating wear rates substantially equiva-
history of successful use for orthopedic implant application
lent to or less than UHMWPE as determined by Practice F732.
shall exhibit corrosion resistance equal to or better than one of
NOTE 2—In situations where the pin-on-flat test may not be considered
the materials listed in 5.1.1 when tested in accordance with
appropriate, other test methods may be considered.
Test Method F746.
6.5 Porous metal coatings shall be tested according to Test
5.1.3 Biocompatibility— Materials with limited or no his-
MethodF1044(shearstrength)andTestMethodF1147(tensile
t
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