1、Designation: F 1672 95 (Reapproved 2005)Standard Specification forResurfacing Patellar Prosthesis1This standard is issued under the fixed designation F 1672; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision
2、. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This specification covers patellar resurfacing devicesused to provide a functioning articulation between the bones ofthe patella a
3、nd the femur.1.2 This specification is intended to provide basic descrip-tions of material and device geometry. Additionally, thosecharacteristics determined to be important to in-vivo perfor-mance of the device are defined.1.3 This specification does not cover the details for qualityassurance, desi
4、gn control, and production control contained in21 CFR 820 and ISO 9001.NOTE 1Devices for custom applications are not covered by thisspecification.2. Referenced Documents2.1 ASTM Standards:2F75 Specification for Cobalt-28 Chromium-6 MolybdenumAlloy Castings and Casting Alloy for Surgical Implants(UNS
5、 R30075)F86 Practice for Surface Preparation and Marking of Me-tallic Surgical ImplantsF90 Specification for Wrought Cobalt-20 Chromium-15Tungsten-10 Nickle Alloy for Surgical Implant Applica-tions (UNS R30605)F 136 Specification for Wrought Titanium-6 Aluminum-4Vanadium ELI (Extra Low Interstitial)
6、 Alloy for SurgicalImplant Applications (UNS R56401)F 138 Specification for Stainless Steel Bar and Wire forSurgical Implants (Special Quality)F 451 Specification for Acrylic Bone CementF 562 Specification for Wrought Cobalt-35 Nickel 20-Chromium 10-Molybdenum Alloy for Surgical ImplantApplications
7、(UNS R30035)F 563 Specification for Wrought Cobalt-Nickel-Chromium-Molybdenum-Tungsten-Iron Alloy for Surgical ImplantApplications3F 603 Specification for High-Purity Dense Aluminum Ox-ide for Surgical Implant ApplicationF 648 Specification for Ultra-High-Molecular-Weight Poly-ethylene Powder and Fa
8、bricated Form for Surgical Im-plants3F 732 Test Method for Wear Testing of Polymeric Materialsfor Use in Total Joint ProsthesesF 745 Specification for 18 Chromium-12.5 Nickel-2.5 Mo-lybdenum Stainless Steel for Cast and SolutionAnnealedSurgical Implant ApplicationsF 746 Test Method for Pitting or Cr
9、evice Corrosion ofMetallic Surgical Implant MaterialsF 748 Practice for Selecting Generic Biological Test Meth-ods for Materials and DevicesF 799 Specification for Cobalt-28 Chromium-6 Molybde-num Alloy Forgings for Surgical ImplantsF 981 Practice for Assessment of Compatibility of Bioma-terials for
10、 Surgical Implants with Respect to Effect ofMaterials on Muscle and BoneF 983 Practice for Permanent Marking of Orthopaedic Im-plant ComponentsF 1044 Test Method for Shear Testing of Calcium Phos-phate Coatings and Metallic Coatings.F 1108 Specification for Ti6Al4V Alloy Castings for Surgi-cal Impla
11、ntsF 1147 Test Method for Tension Testing of Calcium Phos-phate and Metal Coatings2.2 Government Document:21 CFR 820-Good Manufacturing Practice for MedicalDevices41This specification is under the jurisdiction of ASTM Committee F04 onMedical and Surgical Materials and Devices and is under the direct
12、 responsibility ofSubcommittee F04.22 on Arthroplasty.Current edition approved Oct. 1, 2005. Published October 2005. Originallyapproved in 1995. Last previous edition approved in 2000 as F 1672 95 (2000).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Se
13、rvice at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn.4Available from Superintendent of Documents, U.S. Government PrintingOffice, Washington, DC 20402.1Copyright ASTM International, 100 Barr Harbor D
14、rive, PO Box C700, West Conshohocken, PA 19428-2959, United States.2.3 ISO Standard:ISO 9001-Quality Systems-Model for Quality Assurance inDesign/Development, Production, Installation, and Ser-vicing53. Terminology3.1 DefinitionsDimensions defined as follows are mea-sured in whole or in part in the
15、sagittal, transverse, and coronal(or frontal) planes as appropriate. See Fig. 1 and Fig. 2.3.1.1 T1 total overall prosthetic thickness, for example,from the apex of the dome to the free end of pegs or otherfixation geometry.3.1.2 T2 thickness of the patellar prosthesis from theplane of the bone-pros
16、thesis interface (excluding pegs, keels,and so forth) to the apex of the articulating surface.3.1.3 T3 minimum polymer thickness of the patellarprosthesis in direct contact with the femoral component that is“at risk” for wear; this is measured perpendicular to the tangentof the wear surface at the p
17、oint of contact with the femoralcomponent.3.1.4 DiscussionThe dimension T3is described in Fig. 1and Fig. 2 to be a distance from a surface contact point to aninternal peg or an edge of the metal back. The exact location ofthe minimum thickness at risk may be at a different site andwill depend on the
18、 design of the patella prosthesis and themating femoral component. For devices manufactured from asingle material, T3should be measured from the wear surfaceto the back of the fixation surface.3.1.5 W1maximum medial-lateral width of the articulat-ing surface in the frontal plane.3.1.6 W2maximum medi
19、al-lateral width of the metal backin the frontal plane.3.1.7 H1articulating surface superior-inferior height in thefrontal plane.3.1.8 H2metal back superior-inferior height in the frontalplane.3.1.9 Rcradius of curvature for single radius axisymmet-ric domes only.3.2 Definitions of Terms Specific to
20、 This Standard:3.2.1 domea style of axisymmetric prosthesis that has asingle uniform radius of curvature (that is, button).3.2.2 fixation elementany peg, keel, or other protrusionfrom the nonarticulating side of the patellar component in-tended to increase the surface contact or mechanical interlock
21、between the component, the bonding agent (bone cement) orthe natural patella, or both.3.2.3 marker wirea nonstructural, generally thin metallicwire, designed to be apparent on X-rays taken after placementof implants that otherwise would be nonapparent on suchX-rays.3.2.4 metal backa metal structure
22、supporting the articu-lating surface material. This may be fixed rigidly to thearticulating surface or it may be fixed such that it allows thearticulating surface to rotate or translate.3.2.5 radii of curvaturethe geometry of the articularsurface may be described by a list of appropriate radii ofcur
23、vature.3.2.6 sombreroa style of axisymmetric prosthesis that hasmultiple radii of curvature. (SeeFig. 1c.)4. Classification4.1 Patellar replacement devices may be classified accord-ing to geometry:4.1.1 Axisymmetric The articulating surface is symmetricon an axis perpendicular to the prepared bondin
24、g surface (forexample, Dome patellas and sombrero-type patellas). See Fig.1.4.1.2 Nonsymmetric The articulating surface is not axi-symmetric but may be symmetric on a plane. Examples of thistype are anatomical or oblong prosthesis. See Fig. 2.4.2 It is important to define the type of fixation geomet
25、ry sothat the user can understand the degree of bone invasion:4.2.1 PegNumber, size (for example: length, width, di-ameter, and so forth), and location and4.2.2 KeelWidth, length, thickness, geometry, and loca-tion.5. Materials and Manufacture5.1 The choice of materials is understood to be a necessa
26、rybut not sufficient ensurance of function of the device madefrom them.All devices conforming to this specification shall befabricated from materials, with adequate mechanical strengthand durability, corrosion resistance and biocompatibility.5.1.1 Mechanical StrengthComponents of various pros-theses
27、 have been successfully fabricated from the followingmaterials. See Specifications F 75, F 90, F 136, F 138, F 562,F 563, F 603, F 648, F 745, F 799, and F 1108. The articulating5Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036.(a) (b) (c)NOTE
28、 1Figure 1(a) and (b) show a dome style and Fig. 1(c) shows asombrero style.FIG. 1 Two Versions of Axisymmetric Patella Prostheses(a) Transverse Cross Section WithLateral to the Right(b) Sagittal Cross SectionFIG. 2 Example of a Nonsymmetric Patella ProsthesisF 1672 95 (2005)2surface should be fabri
29、cated from a material such as UHM-WPE in accordance with Specification F 648.5.1.2 Corrosion ResistanceMaterials with limited or nohistory of successful use for orthopedic implant applicationmust be determined to exhibit corrosion resistance equal to orbetter than one of the materials listed in 5.1.
30、1 when tested inaccordance with Test Method F 746.5.1.3 Biocompatibility Materials with limited or no his-tory of successful use for orthopedic implant application mustbe determined to exhibit acceptable biological response equalto or better than one of the materials listed in 5.1.1 when testedin ac
31、cordance with Practices F 748 and F 981.6. Performance Requirements6.1 The implant shall be capable of withstanding sustainedstatic and dynamic physiologic loads without compromise ofits function for the intended use and environment. At this timethere are no device-specific test methods and there ar
32、e noacceptable performance levels. Device testing shall be done inkeeping with the implants intended function.6.2 There are relevant failure modes listed as follows which,at minimum, shall be considered in the evaluation of safety andefficacy of a patella prosthesis. Literature references (18)6have
33、been included in the rationale statement in support ofthese failure modes.6.2.1 Dislocation or Lateral SubluxationThe subluxationover the lateral portion of the femoral articular surface. Thishas occurred in the past and is design and patient specific.6.2.2 Component DisassociationDevices made from
34、mul-tiple layers or components have disassociated under clinicaluse (for example, articulating surface from the metal back,porous coating from the metal back, and so forth). Thisdisassociation may be evaluated through shear loading orcompression loading, or a combination of the two.6.2.3 Fixation Fa
35、ilure Devices have loosened at theinterface with bone.Attachment mechanisms such as pegs havesheared or failed. Components have become loose within thebone cement.6.2.4 Device Fracture Partial or complete fracture ofeither the articular surface or the metal back.6.2.5 Articular Surface WearPatella p
36、rostheses havefailed due to excessive wear of the articulating surface result-ing in polymer debris and in some cases “wear through” of thearticular surface with subsequent metal-on-metal wear debris.Thin UHMWPE may accelerate this wear but it is designdependent.6.3 The failure modes may be addresse
37、d through relevanttesting (for example, shear testing of device component inter-faces) and analysis (for example, internal stress analysis due toloading). The testing may encompass some combination ofstatic and dynamic loading environments.6.4 Polymeric components as manufactured shall be madefrom m
38、aterials demonstrating wear rates substantially equiva-lent to or less than UHMWPE as determined by Practice F 732.NOTE 2In situations where the pin-on-flat test may not be consideredappropriate, other test methods may be considered.6.5 Porous metal coatings shall be tested according to TestMethod F
39、 1044 (shear strength) and Test Method F 1147(tensile strength).7. Dimensions, Mass, and Permissible Variations7.1 Dimensions of patellar resurfacing devices shall be asdesignated, but not limited to those described, in Fig. 1 and Fig.2. The tolerance and methods of dimensional measurementmust be so
40、ught to conform with industry practice and, when-ever possible, on an international basis.8. Finish and Product Marking8.1 Items conforming to this specification shall be finishedin accordance with Practice F86, where applicable.8.2 Polymeric Bearing Surface FinishShall conform tothe manufacturers d
41、ocumented standards concerning concen-tricity, sphericity, and surface roughness, where applicable.8.3 The manufacturer, lot number, and material type shall bemarked, space permitting, on the device in accordance withPractices F 86 and F 983 in the order of priority listed.8.4 Optional marking shall
42、 specify orientation for non-symmetric devices.8.5 If one of the components is not radiographically opaque,it may be appropriately marked for radiographic evaluation.The marker wire is a noncritical element and may not benecessary. If a marker wire is used it should be placed in anoncritical area to
43、 avoid degrading the structural and functionalproperties of the device.9. Packaging and Package Marking9.1 Adequate dimensioning to describe overall size andshape (see Fig. 1 and Fig. 2 for examples) shall be included inthe product labeling.9.2 The material(s) used for the implant shall be specified
44、on the package labels and inserts.10. Keywords10.1 arthroplasty; patella; prosthesis6The boldface numbers given in parentheses refer to a list of references at theend of the text.F 1672 95 (2005)3APPENDIX(Nonmandatory Information)X1. RATIONALE STATEMENTX1.1 The objectives of this specification are t
45、o establishguidelines for the manufacture and function of components forpatellar replacement. Current prostheses include single mate-rial designs and multiple material/component designs all pre-assembled at the manufacturing site. Some multicomponentdesign allow a certain degree of mobility of the b
46、earing surfaceover the fixation surface. Patellar replacement parts are in-tended for use in a patient who is skeletally mature. They willbe subjected to considerable dynamic loads in a corrosiveenvironment and virtually continuous motion at the bearingsurfaces.X1.2 This specification is designed to
47、 provide a standard-ization of device terminology, classification, dimensions, andlabeling; alert designers to potential failure mechanisms suchas disassociation, excessive wear, dislocation, and so forth(Refs (1-8); and provide guidance regarding suitable materialsfor fabrication based on current t
48、echnology and clinical use.X1.3 Laboratory tests to accurately simulate physiologicalloads, aggressive electrolytes, and complex constituents ofbody fluids cannot to date entirely simulate long-term in-vivoperformance. It is recognized that failure of the arthroplastycan occur without failure of the
49、 device itself. Long-termprojections of satisfactory performance can be suggested butnot accurately predicted using available testing procedures.This specification identifies those factors felt to be important toensure a satisfactory useful prosthetic life.X1.4 Under applicable documents and materials, the listsreflect the current state of the art. It is recognized that shouldmaterials not now included appear and be proved acceptable,they shall be inserted in the process of revision. To date the vastmajority of patella prostheses have been impla
