1、Designation: F 755 99 (Reapproved 2005)Standard Specification forSelection of Porous Polyethylene for Use in SurgicalImplants1This standard is issued under the fixed designation F 755; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision
2、, the year of last revision. 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 the properties and test meth-ods for porous high density and ultra high molec
3、ular weightpolyethylenes intended for use in surgical implants.The porouspolyethylene may be used as a free standing product or as acoating on a substrate in nonloaded applications.1.2 Evaluation of tissue response to a porous polyethylenemust be completed. Guidance in establishing biocompatibilitym
4、ay be found in the list of references.1.3 Clinical experience and animal studies have shown thattissue will grow into the open pores of porous polyethylene.The tissue ingrowth into the pores may allow for the establish-ment of implant fixation.1.4 This section does not purport to address all of the
5、safetyconcerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety andhealth practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 638 Test Method for Tensile Pro
6、perties of PlasticsD 732 Test Method for Shear Strength of Plastics by PunchToolD 790 Test Methods for Flexural Properties of Unreinforcedand Reinforced Plastics and Electrical Insulating MaterialsD 883 Terminology Relating to PlasticsD 1238 Test Method for Melt Flow Rates of Thermoplasticsby Extrus
7、ion PlastometerD 1505 Test Method for Density of Plastics by the Density-Gradient TechniqueD 1621 Test Method for Compressive Properties of RigidCellular PlasticsD 1623 Test Method for Tensile and Tensile AdhesionProperties of Rigid Cellular PlasticsD 1898 Practice for Sampling of Plastics3D 2238 Te
8、st Methods for Absorbance of Polyethylene Dueto Methyl Groups at 1378 cm1D 2873 Test Method for Interior Porosity of Poly(VinylChloride) (PVC) Resins by Mercury Intrusion Porosim-etry3E 562 Practice for Determining Volume Fraction by Sys-tematic Manual Point CountF 316 Test Methods for Pore Size Cha
9、racteristics of Mem-brane Filters by Bubble Point and Mean Flow Pore TestF 469 Practice for Assessment of Compatibility of Nonpo-rous Polymeric Materials for Surgical Implants With Re-gard to Effect of Materials on Tissue3F 648 Specification for Ultra-High-Molecular-Weight Poly-ethylene Powder and F
10、abricated Form for Surgical Im-plantsF 748 Practice for Selecting Generic Biological Test Meth-ods for Materials and DevicesF 763 Practice for Short-Term Screening of Implant Mate-rialsF 981 Practice for Assessment of Compatibility of Bioma-terials for Surgical Implants with Respect to Effect ofMate
11、rials on Muscle and Bone2.2 Other Documents:Code of Federal Regulations Title 21, Paragraph 177.15204U.S. Pharmacopeia, Vol 23, 199553. Significance and Use3.1 Porous polyethylene is a matrix of substantially opencells, interconnected to form multidirectional paths. Perfor-mance of these structures,
12、 including tissue ingrowth, dependsupon the biocompatibility of the polymer, average pore andinterstitial opening diameters (ordinarily referred to as averagepore size) in conjunction with void volume (referred to as porevolume or percent porosity).3.2 This specification is applicable to all device
13、standards inwhich a porous polyethylene is used. A complete list of end1This specification is under the jurisdiction of ASTM Committee F04 onMedical and Surgical Materials and Devices and is the direct responsibility ofSubcommittee F04.11 on Polymeric Materials.Current edition approved Mar. 1, 2005.
14、 Published March 2005. Originallyapproved in 1982. Last previous edition approved in 1999 as F 755 99e1.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standard
15、s Document Summary page onthe ASTM website.3Withdrawn.4Available from U.S. Government Printing Office Superintendent of Documents,732 N. Capitol St., NW, Mail Stop: SDE, Washington, DC 20401.5Available from U.S. Pharmacopeia (USP), 12601 Twinbrook Pkwy., Rockville,MD 20852.1Copyright ASTM Internatio
16、nal, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.uses has not been established. In those cases where the use ofa porous polyethylene has not been established, the mechanicaland physical characteristics required shall be determined byproper testing. The pore si
17、ze, pore volume, and the mechanicalproperties will be specified in the particular device standard.4. Raw Material Requirements4.1 The polyethylene plastic shall consist of basic polymersmade with ethylene as essentially the sole monomer as definedin Terminology D 883.4.2 High-density polyethylene sh
18、all exhibit a density of notless than 0.941 g/cm3when tested in accordance with TestMethod D 1505.4.3 Ultra-high-molecular-weight polyethylene shall con-form to those sections of Specification F 648 that apply to baseresin.4.4 Particular raw materials shall contain no dirt or otherforeign matter whi
19、ch will cause the end product to fail to meetthe product requirement specified in 5.2.4.5 The polyethylene resin shall conform to all parts ofParagraph 177.1520 of Title 21 which apply to polyethylene.4.6 The polymer shall be characterized by determining theinfrared absorption spectrum.An acceptable
20、 procedure may befound in Test Methods D 2238.4.7 The polymer shall be characterized by one or more ofthe following test methods:4.7.1 The polymer shall be characterized by determiningthe melt point range and rate of melt by thermal analysis.4.7.2 The compositional characteristics of the polymer sha
21、llbe analyzed by thermogravimetric analysis.4.7.3 The flow rate of high density polyethylene shall bedetermined in accordance with Test Method D 1238.5. Product Requirements Product Requirements5.1 Until a porous polymer biocompatibility standard isavailable, porous polyethylene shall be screened by
22、 biocom-patibility and toxicology tests applicable to its end use.Biological test procedures appropriate to determine biologicalsafety and tissue reactions are described in Practices F 748 andF 981 and the United States Pharmacopeia which recommendsgeneric biological test methods according to end us
23、e applica-tions. Short term screening for implant materials are describedin Practice F 763.5.2 The surface of the porous polyethylene shall not containparticles of residue or loose particles of plastic of a diametergreater than 300 m. The concentration of particles visible at83 magnification shall n
24、ot be greater than 10 particles/400cm2.5.3 The level of extractables found in the porous productwhen tested in accordance with 4.5 shall not increase from thatfound in the raw material.5.4 The porous product shall be inspected under 83magnification to assure that the surface porosity is open.5.5 The
25、 average pore size shall be specified by vendor-useragreement and shall be held to within 20 % of the nominalvalue unless the end-use application requires less deviation.5.6 Porous product quality and uniformity shall be assuredby the appropriate test methods as specified by vendor-useragreement and
26、 listed in Section 6.6. Test MethodsNOTE 1The shape and end use of the porous product dictates whichtests are appropriate. For example, it is impossible to perform a bubblepoint analysis on a total ossicular replacement, while mercury intrusionporosimetry is quite acceptable. A flexural test may be
27、an acceptablenondestructive test where tensile strength tests are destructive.6.1 All mechanical and physical tests shall be sampled asrequired in Practice D 1898.6.2 Average pore size shall be established by appropriatetest methods such as is found in Test Method F 316 or bymercury intrusion porosi
28、metry. Test Method D 2873 is anacceptable method.6.3 Average pore volume shall be established using one ofthe following methods:6.3.1 Pore volume can be measured by mercury intrusionporosimetry. Test Method D 2873 is an acceptable method.6.3.2 Pore volume can be approximated by measurement ofweight
29、of a nonsolvent saturant of known gravity and relatingits volume to the matrix volume.6.3.3 Pore volume can be estimated by optical microscopyas described in Practice E 562.6.4 The tensile properties shall be determined in accor-dance with Test Method D 638. Test Method D 1623 may beused as an alter
30、native method.6.5 The compressive properties shall be determined inaccordance with Test Method D 1621.6.6 The flexural properties shall be determined in accor-dance with Test Methods D 790.6.7 The shear properties shall be determined in accordancewith Test Method D 732.7. Certification7.1 Vendor of
31、Porous Materials:7.1.1 Vendor shall certify that the raw material conforms toSection 4 of this specification.7.1.2 Vendor shall certify that the porous polyethyleneconforms to Section 5 of this specification and is made of thesame raw material as has been characterized by Section 4.7.1.3 Vendor shal
32、l certify that the mechanical properties asdetermined by 6.4-6.7 conform to the vendor-user agreement.7.1.4 Porosity requirements as determined by 6.2 and 6.3shall be certified by the vendor to conform to the vendor-useragreement.7.1.5 Vendor shall specify in the certification report all testmethods
33、 used.NOTE 2Certification is employed since verification would alter ordestroy functionality.8. Keywords8.1 plastic surgical devices/applications; polyethylene (PE)plastics/surgical implant applications; polymers-surgical appli-cantF 755 99 (2005)2APPENDIXES(Nonmandatory Information)X1. RATIONALEX1.
34、1 The use of some solid polyethylenes in vivo has beenwell established. Because of their mechanical and physicalproperties, some porous polyethylenes have also shown con-siderable promise for many in vivo applications. The list ofapplications currently being investigated is quite lengthy but,even so
35、, does not exhaust the possibilities. It is to be expectedthat as applications are developed the properties of the porouspolyethylene which are acceptable for a given application willbe uniquely specified. This will necessitate the writing of astandard for each end-use product.X1.2 It is not the pur
36、pose of this generic standard toeliminate a priori any candidate porous polyethylene. For thisreason, it is seen that in some respects the requirements for thisare rather broad. The pore size and pore volumes are notspecified since they will be a function of the end use and thetype of tissue ingrowt
37、h desired. The same is true of themechanical properties. The function of this specification is tospecify those characteristics and tests to which a material isexpected to conform to be used as a surgical implant and to becalled porous polyethylene. To this end, the following fiveareas are addressed:
38、 (1) raw material requirements; (2) limits ofimpurities and extractables; (3) end product property testmethods; (4) tissue response test methods; and (5) responsi-bilities of vendor certification.X1.3 Porous polyethylenes which conform to this specifi-cation will be safe for selected applications an
39、d of a uniformhigh quality. Those properties which are critical to its beingefficacious are the responsibility of an end-use product stan-dard.X2. BIOCOMPATIBILITYX2.1 The material covered by this specification has beenemployed successfully in human implant applications in con-tact with soft tissue
40、and bone for over a decade. Due to the wellcharacterized level of biological response exhibited by thismaterial, the ultra high molecular weight form (Practice F 648)has been used as a control material in Practice F 981.X2.2 No known surgical implant material has ever beenshown to be completely free
41、 of adverse reactions in the humanbody. However, long-term clinical experience of use of thismaterial referred to in this specification has shown that anacceptable level of biological response can be expected, if thematerial is used in appropriate applications.ASTM International takes no position re
42、specting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This
43、 standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM Inter
44、national Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown b
45、elow.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).F 755 99 (2005)3
