ASTM F1672-95(2000)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: F 1672 – 95 (Reapproved 2000)
Standard Specification for
Resurfacing Patellar Prosthesis
This standard is issued under the fixed designation F 1672; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope Molybdenum-Tungsten-Iron Alloy for Surgical Implant
Applications
1.1 This specification covers patellar resurfacing devices
F 603 Specification for High-Purity Dense Aluminum Ox-
used to provide a functioning articulation between the bones of
ide for Surgical Implant Applications
the patella and the femur.
F 648 Specification for Ultra-High-Molecular-Weight Poly-
1.2 This specification is intended to provide basic descrip-
ethylene Powder and Fabricated Form for Surgical Im-
tions of material and device geometry. Additionally, those
plants
characteristics determined to be important to in-vivo perfor-
F 732 Practice for Reciprocating Pin-on-Flat Evaluation of
mance of the device are defined.
Friction and Wear Properties of Polymeric Materials for
1.3 This specification does not cover the details for quality
Use in Total Joint Prostheses
assurance, design control, and production control contained in
F 745 Specification for 18 Chromium-12.5 Nickel-2.5 Mo-
21 CFR 820 and ISO 9001.
lybdenumStainlessSteelforCastandSolution—Annealed
NOTE 1—Devices for custom applications are not covered by this 2
Surgical Implant Applications
specification.
F 746 Test Method for Pitting or Crevice Corrosion of
Metallic Surgical Implant Materials
2. Referenced Documents
F 748 Practice for Selecting Generic Biological Test Meth-
2.1 ASTM Standards:
ods for Materials and Devices
F75 SpecificationforCastCobalt-Chromium-Molybdenum
F 799 Specification for Cobalt-28 Chromium-6 Molybde-
Alloy for Surgical Implant Applications
num Alloy Forgings for Surgical Implants
F86 Practice for Surface Preparation and Marking of Me-
F 981 Practice for Assessment of Compatibility of Bioma-
tallic Surgical Implants
terials for Surgical Implants with Respect to Effect of
F90 Specification for Wrought Cobalt-Chromium-Nickel-
Materials on Muscle and Bone
Tungsten Alloy for Surgical Implant Applications
F 983 Practice for Permanent Marking of Orthopaedic Im-
F 136 Specification for Wrought Titanium 6Al-4V ELI
plant Components
Alloy for Surgical Implant Applications
F 1044 Test Method for Shear Testing of Porous Metal
F 138 Specification for Stainless Steel Bar and Wire for
Coatings
Surgical Implants (Special Quality)
F 1108 Specification for Ti6Al4VAlloy Castings for Surgi-
F 451 Specification for Acrylic Bone Cement
cal Implants
F 562 Specification for Wrought Cobalt-35 Nickel 20-
F 1147 Test Method for Tension Testing of Porous Metal
Chromium 10-Molybdenum Alloy for Surgical Implant
Coatings
Applications
2.2 Government Document:
F 563 Specification for Wrought Cobalt-Nickel-Chromium-
21 CFR 820-Good Manufacturing Practice for Medical
Devices
2.3 ISO Standard:
This specification is under the jurisdiction of ASTM Committee F04 on
Medical and Surgical Materials and Devices and is under the direct responsibility of
Subcommittee F04.22 on Arthroplasty. Discontinued; see 1994 Annual Book of ASTM Standards, Vol 13.01.
Current edition approved Nov. 10, 1995. Published May 1996. Available from Superintendent of Documents, U.S. Government Printing
Annual Book of ASTM Standards, Vol 13.01. Office, Washington, DC 20402.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
F 1672 – 95 (2000)
ISO 9001-Quality Systems-Model for Quality Assurance in 3.1.5 W —maximum medial-lateral width of the articulat-
Design/Development, Production, Installation, and Ser- ing surface in the frontal plane.
vicing 3.1.6 W —maximum medial-lateral width of the metal back
in the frontal plane.
3. Terminology
3.1.7 H —articulatingsurfacesuperior-inferiorheightinthe
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 axisymmetric 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.
3.2.3 marker wire—a nonstructural, generally thin metallic
wire, designed to be apparent on X-rays taken after placement
(a) (b) (c)
of implants that otherwise would be nonapparent on such
X-rays.
NOTE 1—Figure 1(a) and (b) show a dome style and Fig. 1(c) shows a
3.2.4 metal back—a metal structure supporting the articu-
sombrero style.
lating surface material. This may be fixed rigidly to the
FIG. 1 Two Versions of Axisymmetric Patella Prostheses
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.
3.2.6 sombrero—a style of axisymmetric prosthesis that has
multiple radii of curvature. (See Fig. 1Fig. 1c.)
(a) Transverse Cross Section With (b) Sagittal Cross Section
4. Classification
Lateral to the Right
4.1 Patellar replacement devices may be classified accord-
FIG. 2 Example of a Nonsymmetric Patella Prosthesis
ing to geometry:
4.1.1 Axisymmetric— The articulating surface is symmetric
3.1.1 T — total overall prosthetic thickness, for example, on an axis perpendicular to the prepared bonding surface (for
from the apex of the dome to the free end of pegs or other example, Dome patellas and sombrero-type patellas). See Fig.
fixation geometry. 1.
3.1.2 T — thickness of the patellar prosthesis from the 4.1.2 Nonsymmetric— The articulating surface is not axi-
plane of the bone-prosthesis interface (excluding pegs, keels, symmetric but may be symmetric on a plane. Examples of this
and so forth) to the apex of the articulating surface. type are anatomical or oblong prosthesis. See Fig. 2.
4.2 It is important to define the type of fixation geometry so
3.1.3 T — minimum polymer thickness of the patellar
prosthesis in direct contact with the femoral component that is that the user can understand the degree of bone invasion:
4.2.1 Peg—Number, size (for example: length, width, di-
“atrisk”forwear;thisismeasuredperpendiculartothetangent
of the wear surface at the point of contact with the femoral ameter, and so forth), and location and
component. 4.2.2 Keel—Width, length, thickness, geometry, and loca-
3.1.4 Discussion—The dimension T is described in Fig. 1 tion.
and Fig. 2 to be a distance from a surface contact point to an
5. Materials and Manufacture
internal peg or an edge of the metal back.The exact location of
5.1 The choice of materials is understood to be a necessary
the minimum thickness at risk may be at a different site and
but not sufficient ensurance of function of the device made
will depend on the design of the patella prosthesis and the
fromthem.Alldevicesconformingtothisspecificationshallbe
mating femoral component. For devices manufactured from a
fabricated from materials, with adequate mechanical strength
single material, T should be measured from the wear surface
and durability, corrosion resistance and biocompatibility.
to the back of the fixation surface.
5.1.1 Mechanical Strength—Components of various pros-
theses have been successfully fabricated from the following
materials. See Specifications F 75, F 90, F 136, F 138, F 562,
Available from American National Standards Institute, 11 W. 42nd St., 13th
Floor, New York, NY 10036. F 563,F 603,F 648,F 745,F 799,andF 1108.Thearticulating
F 1672 – 95 (2000)
surface should be fabricated from a material such as UHM- 6.3 The failure modes may be addressed through relevant
WPE in accordance with Specification F 648. testing (for example, shear testing of device component inter-
faces) and analysis (for example, internal stress analysis due to
5.1.2 Corrosion Resistance—Materials with limited or no
loading). The testing may encompass some combination of
history of successful use for orthopedic implant application
static and dynamic loading environments.
must be determined to exhibit corrosion resistance equal to or
6.4 Polymeric components as manufactured shall be made
better than one of the materials listed in 5.1.1 when tested in
from materials demonstrating wear rates substantially equiva-
accordance with Test Method F 746.
lenttoorlessthanUHMWPEasdeterminedbyPracticeF 732.
5.1.3 Biocompatibility— Materials with limited or no his-
tory of successful use for orthopedic implant application must
NOTE 2—In situations where the pin-on-flat test may not be considered
be determined to exhibit acceptable biological response equal appropriate, other test methods may be considered.
to or better than one of the materials listed in 5.1.1 when tested
6.5 Porous metal coatings shall be tested according to Test
in accordance with Practices F 748 and F
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