ASTM F1672-95(2005)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: F1672 – 95 (Reapproved 2005)
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 F563 Specification for Wrought Cobalt-20Nickel-
20Chromium-3.5Molybdenum-3.5Tungsten-5Iron Alloy
1.1 This specification covers patellar resurfacing devices
for Surgical Implant Applications (UNS R30563)
used to provide a functioning articulation between the bones of
F603 Specification for High-Purity DenseAluminum Oxide
the patella and the femur.
for Medical Application
1.2 This specification is intended to provide basic descrip-
F648 Specification for Ultra-High-Molecular-Weight Poly-
tions of material and device geometry. Additionally, those
ethylene Powder and Fabricated Form for Surgical Im-
characteristics determined to be important to in-vivo perfor-
plants
mance of the device are defined.
F732 Test Method for Wear Testing of Polymeric Materials
1.3 This specification does not cover the details for quality
Used in Total Joint Prostheses
assurance, design control, and production control contained in
F745 Specification for 18Chromium-12.5Nickel-
21 CFR 820 and ISO 9001.
2.5Molybdenum Stainless Steel for Cast and Solution-
NOTE 1—Devices for custom applications are not covered by this
Annealed Surgical Implant Applications
specification.
F746 Test Method for Pitting or Crevice Corrosion of
Metallic Surgical Implant Materials
2. Referenced Documents
F748 Practice for Selecting Generic Biological Test Meth-
2.1 ASTM Standards:
ods for Materials and Devices
F75 Specification for Cobalt-28 Chromium-6 Molybdenum
F799 Specification for Cobalt-28Chromium-6Molybdenum
Alloy Castings and Casting Alloy for Surgical Implants
Alloy Forgings for Surgical Implants (UNS R31537,
(UNS R30075)
R31538, R31539)
F86 Practice for Surface Preparation and Marking of Me-
F981 Practice forAssessment of Compatibility of Biomate-
tallic Surgical Implants
rials for Surgical Implants with Respect to Effect of
F90 Specification for Wrought Cobalt-20Chromium-
Materials on Muscle and Bone
15Tungsten-10Nickel Alloy for Surgical Implant Applica-
F983 Practice for Permanent Marking of Orthopaedic Im-
tions (UNS R30605)
plant Components
F136 Specification for Wrought Titanium-6Aluminum-
F1044 Test Method for ShearTesting of Calcium Phosphate
4Vanadium ELI (Extra Low Interstitial)Alloy for Surgical
Coatings and Metallic Coatings
Implant Applications (UNS R56401)
F1108 Specification for Titanium-6Aluminum-4Vanadium
F138 Specification for Wrought 18Chromium-14Nickel-
Alloy Castings for Surgical Implants (UNS R56406)
2.5Molybdenum Stainless Steel Bar and Wire for Surgical
F1147 Test Method for Tension Testing of Calcium Phos-
Implants (UNS S31673)
phate and Metallic Coatings
F451 Specification for Acrylic Bone Cement
2.2 Government Document:
F562 Specification for Wrought 35Cobalt-35Nickel-
21 CFR 820-Good Manufacturing Practice for Medical
20Chromium-10Molybdenum Alloy for Surgical Implant
Devices
Applications (UNS R30035)
2.3 ISO Standard:
ISO 9001-Quality Systems-Model for Quality Assurance in
Design/Development, Production, Installation, and Ser-
This specification is under the jurisdiction of ASTM Committee F04 on
Medical and Surgical Materials and Devices and is under the direct responsibility of
vicing
Subcommittee F04.22 on Arthroplasty.
Current edition approved Oct. 1, 2005. Published October 2005. Originally
approved in 1995. Last previous edition approved in 2000 as F1672 – 95 (2000).
DOI: 10.1520/F1672-95R05. Withdrawn. The last approved version of this historical standard is referenced
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F1672 – 95 (2005)
3. Terminology 3.1.9 Rc—radius of curvature for single radius axisymmet-
ric domes only.
3.1 Definitions—Dimensions defined as follows are mea-
3.2 Definitions of Terms Specific to This Standard:
sured in whole or in part in the sagittal, transverse, and coronal
3.2.1 dome—a style of axisymmetric prosthesis that has a
(or frontal) planes as appropriate. See Fig. 1 and Fig. 2.
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.
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 be nonapparent 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
(a) (b) (c)
articulating surface or it may be fixed such that it allows the
articulating surface to rotate or translate.
NOTE 1—Figure 1(a) and (b) show a dome style and Fig. 1(c) shows a
3.2.5 radii of curvature—the geometry of the articular
sombrero style.
surface may be described by a list of appropriate radii of
FIG. 1 Two Versions of Axisymmetric Patella Prostheses
curvature.
3.2.6 sombrero—a style of axisymmetric prosthesis that has
multiple radii of curvature. (SeeFig. 1c.)
4. Classification
4.1 Patellar replacement devices may be classified accord-
ing to geometry:
4.1.1 Axisymmetric— The articulating surface is symmetric
(a) Transverse Cross Section With (b) Sagittal Cross Section
Lateral to the Right
on an axis perpendicular to the prepared bonding surface (for
FIG. 2 Example of a Nonsymmetric Patella Prosthesis example, Dome patellas and sombrero-type patellas). See Fig.
1.
4.1.2 Nonsymmetric— The articulating surface is not axi-
3.1.1 T — total overall prosthetic thickness, for example,
symmetric but may be symmetric on a plane. Examples of this
from the apex of the dome to the free end of pegs or other
type are anatomical or oblong prosthesis. See Fig. 2.
fixation geometry.
4.2 It is important to define the type of fixation geometry so
3.1.2 T — thickness of the patellar prosthesis from the
that the user can understand the degree of bone invasion:
plane of the bone-prosthesis interface (excluding pegs, keels,
4.2.1 Peg—Number, size (for example: length, width, di-
and so forth) to the apex of the articulating surface.
ameter, and so forth), and location and
3.1.3 T — minimum polymer thickness of the patellar
4.2.2 Keel—Width, length, thickness, geometry, and loca-
prosthesis in direct contact with the femoral component that is
tion.
“atrisk”forwear;thisismeasuredperpendiculartothetangent
of the wear surface at the point of contact with the femoral
5. Materials and Manufacture
component.
3.1.4 Discussion—The dimension T is described in Fig. 1 5.1 The choice of materials is understood to be a necessary
and Fig. 2 to be a distance from a surface contact point to an but not sufficient ensurance of function of the device made
internal peg or an edge of the metal back.The exact location of fromthem.Alldevicesconformingtothisspecificationshallbe
the minimum thickness at risk may be at a different site and fabricated from materials, with adequate mechanical strength
and durability, corrosion resistance and biocompatibility.
will depend on the design of the patella prosthesis and the
mating femoral component. For devices manufactured from a 5.1.1 Mechanical Strength—Components of various pros-
single material, T should be measured from the wear surface theses have been successfully fabricated from the following
to the back of the fixation surface. materials. See Specifications F75, F90, F136, F138, F562,
3.1.5 W —maximum medial-lateral width of the articulat- F563, F603, F648, F745, F799, and F1108. The articulating
ing surface in the frontal plane. surface should be fabricated from a material such as UHM-
3.1.6 W —maximum medial-lateral width of the metal back WPE in accordance with Specification F648.
in the frontal plane. 5.1.2 Corrosion Resistance—Materials with limited or no
3.1.7 H —articulatingsurfacesuperior-inferiorheightinthe history of successful use for orthopedic implant application
frontal plane. must be determined to exhibit corrosion resistance equal to or
3.1.8 H —metal back superior-inferior height in the frontal better than one of the materials listed in 5.1.1 when tested in
plane. accordance with Test Method F746.
F1672 – 95 (2005)
5.1.3 Biocompatibility— Materials with limited or no his- loading). The testing may encompass some combination of
tory of successful use for orthopedic implant application must static and dynamic loading environments.
be determined to exhibit acceptable biological response equal 6.4 Polymeric components as manufactured shall be made
to or better than one of the materials listed in 5.1.1 when tested from materials demonstrating wear rates substantially equiva-
in accordance with Practices F748 and F981. lent to or less than UHMWPE as determined by Practice F732.
NOTE 2—In situations where the pin-on-flat test may not be considered
6. Performance Requi
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