1 ScopeThis part of ISO 7206 describes test methods for de-termining the endurance properties under specified laboratory conditions, of the head and neck region of stemmed femoral components of total hip joint prostheses and stemmed femoral components used alone in partial hip joint replacement. It applies to modular and non-modular designs made of metallic or non-metallic materials.It also defines the test conditions so that the impor¬tant parameters that affect the components are taken into account, and describes how the specimen is set up for testing.This part of ISO 7206 does not cover methods of examining and reporting of the test specimen; these should be agreed between the test laboratory and the parties submitting the specimen for test.2 Normative referencesThe following standards contain provisions which, through reference in this text, constitute provisions of this part of ISO 7206. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this part of ISO 7206 are encouraged to investi¬gate the possibility of applying the most recent edi¬tions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards.ISO 7206-1:1985, Implants for surgery — Partial and total hip joint prostheses — Part 1: Classification, designation of dimensions and requirements.ISO 7206-3:1988, Implants for surgery — Partial and total hip Joint prostheses — Part 3: Determination of endurance properties of stemmed femoral compo¬nents without application of torsion.ISO 7206-4:1989, Implants for surgery — Partial and total hip joint prostheses — Part 4: Determination of endurance properties of stemmed femoral compo¬nents with application of torsion.3 Nomenclature and designation of dimensionsFor the purposes of this part of ISO 7206, the no-menclature and designation of dimensions given in ISO 7206-1 apply.4 PrincipleEmbedding of the stem of the test specimen in a solid medium. Partial immersion of the protruding part of the test specimen in a fluid test medium. Application of a cyclic load to the head of the test specimen until the head or neck exhibits failure or until the chosen number of cycles has been attained. Subsequent examination of the specimen for defects caused by the loading regime.5 Reagents and materialsUse the reagents and the materials specified in ISO 7206-3 and ISO 7206-4.6 ApparatusUse the apparatus specified in ISO 7206-3 and ISO 7206-4.7 Procedure7.1 Test with load applied parallel (with no torsion effect) to plane of neckPerform the test as described in ISO 7206-3, except as follows:a) Embed the specimen so that the embedding me-dium extends up the stem to the level which, in clinical use, coincides with the transection level of the femur recommended by the manufacturer (see figures 1 and 3).b) Set the testing machine or other instrument to give an indication if the vertical or horizontal component of the specimen deflection exceeds a value of 3 mm greater than the deflection oc¬curring in the first minute of running at test load.7.2 Test with load applied non-parallel (with torsion effect) to plane of neckCarry out the test as described in ISO 7206-4, except as follows:a) Embed the specimen so that the embedding me- dium extends up the stem to the level which, in clinical use, coincides with the transection level of the femur recommended by the manufacturer (see figures 2 and 3).b) Set the testing machine or other instrument to give an indication if the vertical or horizontal component of the specimen deflection exceeds a value of 3 mm greater than the deflection oc¬curring in the first minute of running at test load.8 Test reportThe test report shall include the following infor¬mation:a) a reference to this part of ISO 7206;b) the identity of the test specimen, as stated by the party submitting the specimen for test;c) the embedding medium used;d) the minimum and maximum loads applied and whether applied parallel or non-parallel to the plane of the neck;e) the duration of the test, in cycles;f) the loading frequency;g) the offset angle in degrees;h) a statement of results including location of fracture (if applicable), description of test specimen at the end of the test, and the results of the ex¬amination requested by the party submitting the specimen for test;i) a record of if and why the test was terminated.9 Disposal of test specimensIt is imperative that the test prostheses should not be used for clinical purposes after testing.Care should be exercised in the use of the speci¬mens for further mechanical tests, including endurance tests, because the loading regime may have altered the mechanical properties.
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