1、BRITISH STANDARD BS 7251-1: 1990 Orthopaedic joint prostheses Part1: Specification for general requirementsBS7251-1:1990 This British Standard, having been prepared under the directionof the Health Care Standards Policy Committee, waspublished under the authorityof the Board ofBSIandcomes into effec
2、t on 30April1990 BSI 10-1999 The following BSI references relate to the work on this standard: Committee reference HCC/25 Draft for comment 87/55161 DC ISBN 0 580 17981 8 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Health Care Standa
3、rds Policy Committee (HCC/-) to Technical Committee HCC/25, upon which the following bodies were represented: British Institute of Surgical Technologists British Medical Association British Orthopaedic Association British Steel Industry British Surgical Trades Association Incorporated Department of
4、Health Department of Trade and Industry (National Engineering Laboratory) Royal College of Surgeons of England Scottish Office Coopted members Amendments issued since publication Amd. No. Date of issue CommentsBS7251-1:1990 BSI 10-1999 i Contents Page Committees responsible Inside front cover Forewo
5、rd ii 1 Scope 1 2 Materials for metal components 1 3 Materials for plastics components 1 4 Materials for ceramic components 1 5 General 1 6 Bearing surfaces 1 7 Surface finish 1 8 Sterilization by irradiation 2 9 Packaging 2 10 Marking 2 Appendix A Guidance on the use of joint prostheses 3 Publicati
6、ons referred to Inside back coverBS7251-1:1990 ii BSI 10-1999 Foreword This Part of BS7251 has been prepared under the direction of the Health Care Standards Policy Committee and supersedes BS3531-9:1982, which is withdrawn. General requirements for joint prostheses were first published as BS3531-9:
7、1982. BS3531, published in twenty-three Parts, gave requirements and guidance on joint prostheses, implants for osteosynthesis and materials for the manufacture of surgical implants. BS3531 now applies only to implants for osteosynthesis; requirements and guidance specific to joint prostheses will f
8、orm a separate standard (BS7251); requirements for orthopaedic implants, i.e.aspects common to osteosynthesis and joint replacement, will form another separate standard (BS7254); and requirements and guidance for materials will form two further separate standards (BS7252 covering metals and BS7253 c
9、overing non-metals). Attention is drawn to the recommendations for care and handling of implants and for the retrieval and examination of implants given in BS7254-3 and BS7254-4. This Part of BS7251 is related to ISO5839:1985 “Implants for surgery Orthopaedic joint prostheses Basic requirements”, pu
10、blished by the International Organization for Standardization (ISO). It differs from ISO5839 in a number of details, chiefly related to the metals of construction, the surface finish requirements, the means of sterilization and the marking of ceramic components. This Part of BS7251 differs from the
11、superseded BS3531-9:1982 chiefly in that whereas it requires components of joint prostheses to be marked with a traceability reference, it no longer requires that this reference shall take the form of a unique identifying mark. However, it should be noted that traceability of a component to some par
12、ts of its manufacturing history, in particular to radiographs taken during non-destructive testing to assess the soundness of metal castings, cannot be ensured in the absence of a unique identifying mark. It differs also in permitting metal components to be made from an enlarged range of materials a
13、nd in specifying the material to be used for polyethylene components. Orthopaedic joint prostheses are required to transmit load and translate motion, frequently under highly stressed conditions. The components of joint prostheses should ideally function from the time of implantation for the remaind
14、er of a patients life span. This introduces difficulties in testing suitable materials, because accelerated laboratory studies present major problems and there are difficulties in evaluating the stresses on joint prostheses during use. The objective of BS7251 is to provide a framework within which s
15、urveillance of manufacture can be established, and specifications for components can be developed. Requirements for acrylic bone cement, commonly used in the implantation of joint prostheses, may be found in BS7253-1. Requirements for knee joint prostheses may be found in BS7251-2 and requirements f
16、or hip joint prostheses may be found in BS7251-3 and BS7251-4. Methods for the determination of endurance properties of stemmed femoral components of hip joint prostheses may be found in BS7251-5 and BS7251-6. Consideration is to be given to the preparation of further Parts of BS7251 to cover method
17、s of test of other mechanical properties of joint prostheses. It is strongly recommended that the products specified in this Part of BS7251 should be manufactured according to the recommendations given in the “Guide to Good Manufacturing Practice for Orthopaedic Implants” 1) . 1) Compiled by the Dep
18、artment of Health and Social Security; published and available from Her Majestys Stationery Office. ISBN0113208464.BS7251-1:1990 BSI 10-1999 iii Product certification. Users of this British Standard are advised to consider thedesirability of third party certification of product compliance with this
19、BritishStandard based on testing and continuing surveillance, which may be coupled with assessment of a suppliers quality systems against the appropriate Part of BS5750. Enquiries as to the availability of third party certification schemes will be forwarded by BSI to the Association of Certification
20、 Bodies. If a third party certification scheme does not already exist, users should consider approaching an appropriate body from the list of Association members. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for
21、 their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi toiv, pages1to4, an inside back cover and a back cover. This standard has been updated (see
22、copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.iv blankBS7251-1:1990 BSI 10-1999 1 1 Scope This Part of BS7251 specifies general requirements, including requirements for packaging, for partial and total joint prosthes
23、es used in orthopaedic surgery for the total or partial replacement of joints such as the hip, the knee, the ankle, the shoulder, the elbow, the wrist, the finger and the toe. Guidance on the use of joint prostheses is given in Appendix A. NOTEThe publications referred to in this standard are listed
24、 on the inside back cover. 2 Materials for metal components Metal components of joint prostheses shall be made of one or more of the following, except that different compositions of stainless steel shall not be used in combination with one another and stainless steel shall not be used in combination
25、 with any other metal: Wrought stainless steel of compositions D or E in accordance with BS7252-1; Wrought high-nitrogen stainless steel in accordance with BS7252-9; Wrought unalloyed titanium in accordance with BS7252-2; Wrought titanium 6-aluminium 4-vanadium alloy in accordance with BS7252-3; Cob
26、alt-chromium-molybdenum casting alloy in accordance with BS7252-4; Wrought cobalt-chromium-tungsten-nickel alloy in accordance with BS7252-5; Wrought cobalt-nickel-chromium-molybdenum alloy in accordance with BS7252-6; Forgeable and cold-formed cobalt-chromium-nickel-molybdenum-iron alloy in accorda
27、nce with BS7252-7; Wrought cobalt-nickel-chromium-molybdenum- tungsten-iron alloy in accordance with BS7252-8. Forged components made of stainless steel, wrought titanium and wrought titanium alloy shall be manufactured in accordance with BS3531-3 and castings made of cobalt-chromium-molybdenum allo
28、y shall be in accordance with BS7254-5. NOTEIn the environment to which orthopaedic joint prostheses are exposed, galvanic effects between dissimilar metals are common and can lead to corrosion. Any joint prosthesis not composed entirely of the same alloy should be designed to take full account of t
29、hese effects. The combination of cobalt-chrome alloys, titanium and titanium alloy has been found acceptable in clinical practice. 3 Materials for plastics components Components made of ultra-high molecular mass polyethylene shall be made of material complying with BS7253-4 and BS7253-5. 4 Materials
30、 for ceramic components Ceramic components shall be made of alumina ceramic complying with BS7253-2. 5 General Components of joint prostheses shall be in accordance with the requirements of BS7254-2. NOTEIt is recommended that all components made of or containing plastics materials should be supplie
31、d in the sterile condition. Other components may be supplied in either the sterile or the non-sterile condition. 6 Bearing surfaces No combination of stainless steel, unalloyed titanium and titanium alloys shall form the contiguous bearing surfaces of joint prostheses. NOTEThe following combinations
32、 have been found to be satisfactory: a) stainless steel/polyethylene; b) cobalt-based alloys/polyethylene; c) unalloyed titanium/polyethylene; d) titanium alloy/polyethylene; e) alumina/polyethylene; f) alumina/alumina. 7 Surface finish 7.1 Metals 7.1.1 General. The surfaces of metallic components,
33、when examined under 2 magnification, shall be free from scale, embedded particles, defects with raised edges and from scratches and score marks. The surfaces, when examined under 2 magnification, shall be free from embedded or deposited finishing materials and other contaminants. NOTEComponents shou
34、ld be cleaned, de-greased, rinsed and dried. All surface finishing operations should be performed using an iron-free medium. 7.1.2 Bearing surfaces. Bearing surfaces shall be polished to a mirror finish, and shall comply with BS7251-4. 7.1.3 Non-bearing surfaces. Non-bearing surfaces intended to be
35、in contact with soft tissues shall have either a polished or a satin finish. 7.2 Plastics materials The bearing surfaces of components made of plastics materials shall, when examined under 2 magnification, be free from particulate contamination. Bearing surfaces shall comply with BS7251-4.BS7251-1:1
36、990 2 BSI 10-1999 NOTEAll plastics surfaces should be free from all residues of substances used during the fabrication of the component. Plastics bearing surfaces should not be prepared by a method employing an abrasive or polishing compound. 8 Sterilization by irradiation If methods of sterilizatio
37、n employing ionizing radiation are used, no part of any component shall receive less than25kGy 2)and no non-metallic component shall receive more than35kGy during one sterilization. The dose shall be applied so as to maintain the functional geometry of the component. No non-metallic component shall
38、be sterilized by irradiation by the manufacturer more than twice. The packaging materials for all components which are to be re-sterilized by irradiation by the manufacturer shall be discarded and the component re-packaged prior to sterilization. 9 Packaging Joint prostheses shall be packaged in acc
39、ordance with the requirements of BS7254-1. Bearing surfaces shall be covered to protect the surfaces from damage. The protection shall comprise a material which leaves no debris or deposit on the surface of the prosthesis, nor induces chemical attack on the prosthesis under normal sterilization cond
40、itions. NOTE 1The protective cover on the bearing surfaces of components provided in the non-sterile condition by the manufacturer should be left in place during sterilization. NOTE 2Packaging should be designed to contain and protect the contents and to maintain sterility. Before any method of pack
41、aging is adopted, it should have been evaluated to establish its suitability for the intended purpose. This may be done by demonstrating adequate performance during journey hazard trials designed to simulate the abuses the package will encounter during routine methods of transit and storage. Many of
42、 the components of joint prostheses are heavy. They are frequently transported by air and may be subject to sub-zero temperature and sub-normal atmospheric pressure. These conditions may induce fracture or puncture of the packaging material with the risk of bacterial contamination of a component sup
43、plied in the sterile condition. Containers should be capable of withstanding severe handling conditions. Components made of plastics materials are subject to deterioration if unduly exposed to sunlight and should be stored in the dark. Attention is drawn to BS7254-3 regarding the care and handling o
44、f orthopaedic joint prostheses in clinical establishments. NOTE 3A device which indicates that the package has passed through a sterilizing process may be included in, or applied to, the package. 10 Marking 10.1 Marking of components 10.1.1 General. Components of joint prostheses shall either: a) be
45、 indelibly marked in accordance with BS7254-1 and10.1.2, as appropriate; or b) if the component is too small to be legibly marked, the information required in item a) shall be given on a label, enclosed in the package, and suitable for affixing to the patients notes. NOTE 1All markings should be loc
46、ated in a region of low stress and marking should be performed in such a manner that the mechanical performance and corrosion resistance of the prosthesis are not significantly impaired. The minimum character height regarded as being legible is1mm. NOTE 2Attention is drawn to the fact that traceabil
47、ity of a component to some parts of its manufacturing history, in particular to radiographs taken during non-destructive testing, cannot be ensured in the absence of a unique identifying mark. 10.1.2 Marking of plastics components. Each component made of plastics material shall be marked so as to id
48、entify the batch of material from which the component is made. 10.2 Labelling of unit packages or containers Unit packages or containers shall be labelled in accordance with BS7254-1. In addition, the package or container shall be marked with the markings of the different components it contains (see
49、10.1). If appropriate, instructions for sterilization shall be included. 2) 1Gy=1J/kg=100rad.BS7251-1:1990 BSI 10-1999 3 Appendix A Guidance on the use of joint prostheses A.1 If the unit container of a component made of plastics material is opened outside the control of the manufacturer and the component is not implanted at that time, the component should be discarded. A.2 Ceramic components should not be sterilized by heat when fitted to a femoral stem because the dissimilar coefficients of expansion of the ceramic material and the metal may introduce stresses in t
