1、BRITISH STANDARD BS7254-2: 1990 Orthopaedic implants Part2: Specification for general requirements for materials and finishBS7254-2:1990 This British Standard, having been prepared under the directionof the Health Care Standards Policy Committee, waspublished under the authorityof the Board of BSI a
2、ndcomes into effect on 30April1990 BSI09-1999 The following BSI references relate to the work on this standard: Committee reference HCC/22 Draft for comment88/55737 DC ISBN 0 580 18099 9 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the He
3、alth Care Standards Policy Committee (HCC/-) to Technical Committee HCC/22, upon which the following bodies were represented: British Institute of Surgical Technologists British Investment Casting Trade Association British Medical Association British Orthopaedic Association British Steel Industry Br
4、itish Surgical Trades Association Incorporated Department of Health Institute of Sterile Services Management Medical Sterile Products Association Ministry of Defence National Association of Theatre Nurses Royal College of Surgeons of England Royal Veterinary College Scottish Office Coopted members A
5、mendments issued since publication Amd. No. Date of issue CommentsBS7254-2:1990 BSI 09-1999 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 Orthopaedic implants made of wrought stainless steel 1 3 Orthopaedic implants made of cast cobalt-based alloy 1 4 Orthopaedic
6、implants made of wrought cobalt-based alloy 1 5 Orthopaedic implants made of wrought titanium 1 6 Orthopaedic implants made of wrought titanium alloy 2 7 Orthopaedic implants made of non-metallic materials 2 Table 1 Nomenclature of titanium and titanium alloy 2 Publications referred to Inside back c
7、overBS7254-2:1990 ii BSI 09-1999 Foreword This Part of BS7254 has been prepared under the direction of the Health Care Standards Policy Committee and, together with BS7254-1, supersedes BS3531-1:1980 which is withdrawn. Requirements for orthopaedic implants (then termed “surgical implants”) were fir
8、st published in1962 as BS3531. In1968 a part revision of BS3531:1962 was issued as BS3531-1, which dealt with surgical implants made of all materials. In1980 the first four Parts of a multi-part revision of BS3531 were published, Part1:1980 comprising requirements for general aspects and for marking
9、 and packaging of surgical implants. Between1980 and1988 a further19 Parts of BS3531 were published specifying materials, design and performance, and giving guidance on different types of surgical implants. In view of the growth of the number of Parts, and with a view to facilitating the implementat
10、ion of published and forthcoming ISO implant standards, BS3531 is being restructured. Accordingly, the number BS3531 will be reserved for standards for implants for osteosynthesis, BS7251 will cover joint prostheses, BS7252 will cover metallic materials for surgical implants, BS7253 will cover non-m
11、etallic materials for surgical implants and BS7254 will cover orthopaedic implants, i.e.aspects common to both osteosynthesis and joint replacement. Requirements for marking and packaging of orthopaedic implants are published as BS7254-1. The materials specified are those which are the most suitable
12、 in the light of present knowledge to provide optimum mechanical properties in relation to requirements for corrosion resistance and physiological compatibility with living tissues. All metals will corrode or erode in the body to a greater or lesser extent depending on the local conditions. In deter
13、mining the choice of material to be used in any particular case, due regard should be paid to its mechanical properties, e.g.wrought titanium is unsuitable for load bearing surfaces that involve movement of metal on metal. Orthopaedic implants should not be used again after removal from the patient.
14、 It is strongly recommended that the products specified in this Part of BS7254 should be manufactured according to the recommendations given in the “Guide to Good Manufacturing Practice for Orthopaedic Implants” 1) . Product certification. Users of this British Standard are advised to consider the d
15、esirability of third party certification of product conformity with this British Standard based on testing and continued 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 certifica
16、tion schemes will be forwarded by BSI to the Association of Certification 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
17、 provisions of a contract. Users of British Standards are responsible for 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 andii, pages1 and 2
18、, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. 1) Compiled by the Department of Health and Social Security; published and available from He
19、rMajestys Stationery Office. ISBN0113208464.BS7254-2:1990 BSI 09-1999 1 1 Scope This Part of BS7254 specifies general requirements for materials and finish of orthopaedic implants used for bone surgery including osteosynthesis and joint replacement, and made of wrought austenitic stainless steel, ca
20、st cobalt-based alloys, wrought cobalt-based alloys, wrought titanium, wrought titanium alloy and non-metallic materials. NOTE 1This Part of BS7254 gives requirements for implants for osteosynthesis and for partial and total joint prostheses. These requirements may be referred to in, or superseded b
21、y, Parts of BS3531 and BS7251 as regards particular types of orthopaedic implant. However, it is unlikely that every type of orthopaedic implant will be covered by a Part of BS3531 or BS7251 and, if no individual product specification exists, this Part of BS7254 is intended to give requirements appl
22、icable to orthopaedic implants in general. NOTE 2The titles of the publications referred to in this standard are listed on the inside back cover. 2 Orthopaedic implants made of wrought stainless steel 2.1 Material and fabrication Orthopaedic implants or components of implants shall be machined or fo
23、rged from wrought austenitic stainless steel complying with BS7252-1 or BS7252-9. The implant shall not be made from castings and welding methods shall not be employed. 2.2 Finish The surfaces of implants made of stainless steel shall be free from draw marks, pits, burrs and surface contamination. U
24、nless contra-indicated by requirements for the surface finish and geometry of the product, all surfaces of the implant shall be mechanically polished and/or electro-polished followed by degreasing, cleaning and a final passivation process. Mechanical polishing shall be undertaken with an iron-free a
25、brasive, following which the surfaces shall be degreased and cleaned. Implants shall be degreased and cleaned before any electro-polishing process takes place. Passivation shall be undertaken. After passivation, implants shall be washed and dried. NOTETreatment with aqueous nitric acid solution of a
26、bout1.18 relative density about30% (m/m) at a temperature of between40 C and60 C for at least15min is a recommended passivation process. Other passivation processes which also ensure the removal of iron particles which may have become embedded in the surface during machining operations may be used.
27、In order to ensure, that mechanically polished implants are clean, it is recommended that they should be cleaned by an ultrasonic process using trichloroethylene or other suitable solvent with continuous filtration. 3 Orthopaedic implants made of cast cobalt-based alloy 3.1 Material Orthopaedic impl
28、ants or components of implants shall be made from cast cobalt-chromium-molybdenum alloy complying with BS7252-4. 3.2 Finish The surfaces of implants made of cast cobalt-based alloy shall be free from contamination, pits and marks resulting from the manufacturing process, e.g.grinding, milling and po
29、lishing. All sharp edges and burrs shall be removed. The surface finish shall be a matt finish unless a mechanically polished surface is specially required. The matt finish shall be achieved by an iron-free medium, and subsequently the medium shall be removed from the implant by a cleaning operation
30、. Mechanical polishing shall be achieved by an iron-free polishing medium and traces of polishing medium shall be removed by a cleaning operation. 4 Orthopaedic implants made of wrought cobalt-based alloy 4.1 Material Orthopaedic implants or components of implants shall be machined or forged from wr
31、ought cobalt-based alloy complying with BS7252-5, BS7252-6,BS7252-7 orBS7252-8. They shall not be made from castings. 4.2 Finish The surfaces of implants made of wrought cobalt-based alloys shall be finished in accordance with3.2. 5 Orthopaedic implants made of wrought titanium 5.1 Material Orthopae
32、dic implants or components of implants shall be manufactured by forging, machining or welding of wrought titanium grades4A or4B complying with BS7252-2, except when the design or method of fabrication requires a greater ductility of the material for which grades1,2 or3 may be used, the type with the
33、 highest practicable tensile strength being selected. Forged components shall be descaled and annealed.BS7254-2:1990 2 BSI 09-1999 NOTE 1The five specified grades of wrought commercially pure titanium vary from the weakest grade1 to the strongest grade4B. From the clinical standpoint, the stress imp
34、osed on the majority of surgical implants is such that grade4A material is to be preferred. If the method of fabrication requires a more ductile form of the material than grade4A, grade3material will usually be found to give sufficient strength, for example, for the fabrication of bracket plates req
35、uiring shaping and hip-caps which are spun or pressed. Because of the greater flexibility of wrought titanium as compared with some other materials, orthopaedic implants made of wrought titanium should be designed to give the required degree of rigidity. NOTE 2Within the present state of knowledge,
36、wrought titanium as specified in5.1 may not prove to be suitable for some types of metal-to-metal load-bearing moving surfaces, e.g.jointed components. NOTE 3Commercially pure titanium (all grades), and Ti6-Al4-V may be welded using electron beam, argon arc, plasma arc, resistance welding or other t
37、echniques. In all cases, the weld area, including hot metal remote from the weld, should be protected from atmospheric contamination by carrying out the welding in vacuum or an inert gas environment. NOTE 4The relationship between the current nomenclature of commercially pure titanium grades and tit
38、anium alloy and the obsolete nomenclature is as given in Table 1. 5.2 Finish The surfaces of implants made of titanium shall be free from contamination, pits and marks resulting from the manufacturing process, e.g.grinding, milling, pressing and polishing. The final finish shall be either a mirror p
39、olish achieved by mechanical means or a matt finish achieved by vapour blasting, peening or mechanical polishing. Iron-free abrasives shall be used for polishing and the finished implant shall be cleaned, degreased and treated to free the surface of metallic and other contaminants which may have bec
40、ome embedded during manufacture. NOTETitanium implants may be anodized. 6 Orthopaedic implants made of wrought titanium alloy 6.1 Material Orthopaedic implants or components of implants shall be manufactured by forging, machining or welding of wrought titanium alloy complying with BS7252-3. Forged c
41、omponents shall be descaled and annealed (see also note3 to5.1). 6.2 Finish The surfaces of implants made of wrought titanium alloy shall be finished in accordance with5.2. 7 Orthopaedic implants made of non-metallic materials Orthopaedic implants or components of implants made of ultra-high-molecul
42、ar mass polyethylene shall be made of material complying with BS7253-4 orBS7253-5. Orthopaedic implants or components of implants made of ceramic material shall be made of material complying with BS7253-2. Orthopaedic implants or components of implants made of silicone elastomer shall be made of mat
43、erial complying with BS7253-3. Table 1 Nomenclature of titanium and titanium alloy Source Titanium Titanium alloy Current nomenclature 1 2 3 4A 4B Ti6-Al4-V BS3531-2:1980 T1 T2 T3 T4, T5 TA1 BS3531-1:1968 T115 T120 T130 T155, T160 B1BS7254-2:1990 BSI 09-1999 Publications referred to BS3531, Implants
44、 for osteosynthesis. BS5750, Quality Systems 2) . BS7251, Orthopaedic joint prostheses. BS7252, Metallic materials for surgical implants. BS7252-1, Specification for wrought stainless steel. BS7252-2, Specification for unalloyed titanium. BS7252-3, Specification for wrought titanium6-aluminium4-vana
45、dium alloy. BS7252-4, Specification for cobalt-chromium-molybdenum casting alloy. BS7252-5, Specification for wrought cobalt-chromium-tungsten-nickel alloy. BS7252-6, Specification for wrought cobalt-nickel-chromium-molybdenum alloy. BS7252-7, Specification for cobalt-chromium-nickel-molybdenum-iron
46、 alloy. BS7252-8, Specification for wrought cobalt-nickel-chromium-molybdenum-tungsten-iron alloy. BS7252-9, Specification for high-nitrogen stainless steel. BS7253, Non-metallic materials for surgical implants. BS7253-2, Specification for ceramic materials based on alumina. BS7253-3, Specification
47、for surgical implants made of heat-vulcanized silicone elastomer. BS7253-4, Specification for ultra-high molecular mass polyethylene in powder form. BS7253-5, Specification for ultra-high molecular mass polyethylene in moulded form. BS7254, Orthopaedic implants. BS7254-1, Specification for marking,
48、packaging and labelling. 2) Referred to in the foreword only.BS7254-2: 1990 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing BritishStandards. It presents the UK view on standards in Europe and at the international
49、 level. It is incorporated by Royal Charter. Revisions BritishStandards are updated by amendment or revision. Users of BritishStandards should make sure that they possess the latest amendments or editions. It is the constant aim of BSI to improve the quality of our products and services. We would be grateful if anyone finding an inaccuracy or ambiguity while using this BritishStandard would inform the Secretary of the technical committee responsible, the identity of which can be found on the inside front cover. Tel:02089969000. Fax:02089967400. BSI offers members an
