Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
YY/T 0809 consists of the following parts, under the general title Implants for surgery - Partial and total hip joint prostheses:
——Part 1: Classification and designation of dimensions;
——Part 2: Articulating surfaces made of metallic, ceramic and plastics materials
——Part 3: (Reserved);
——Part 4: Determination of endurance properties and performance of stemmed femoral components;
——Part 5: (Reserved);
——Part 6: Endurance properties testing and performance requirements of neck region of stemmed femoral components;
——Part 7: (Reserved);
——Part 8: Endurance performance of stemmed femoral components with application of torsion;
——Part 9: (Reserved);
——Part 10: Determination of resistance to static load of modular femoral heads;
——Part 11:
——Part 12: Deformation test method for acetabular shells;
——Part 13: Determination of resistance to torque of head fixation of stemmed femoral components.
This is Part 12 of YY/T 0809.
This part is developed in accordance with the rules given in GB/T 1.1-2009.
This standard has been redrafted and modified in relation to ISO 7206-12: 2016 Implants for surgery - Partial and total hip joint prostheses - Part 12: Deformation test method for acetabular shells.
The following main technical changes have been made with respect to ISO 7206-12:2016:
——The adjustment on technical differences are made for the normative references of this Part to adapt to the technical conditions in China. The adjustments are mainly reflected in clause 2 "Normative references", which are shown as follows:
ISO 2768-2 is replaced by GB/T 1184 which is adjusted into the Bibliography.
ISO 21534 is replaced by GB/T 12417.2, which is identical to the international standard;
ISO 7206-1 is replaced by YY/T 0809.1, which is identical to the international standard;
ISO 7206-2 is replaced by YY/T 0809.2, which is modified in relation to the international standard;
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. The issuing body of this document shall not be held responsible for identifying any or all such patent rights.
This part was proposed by the National Medical Products Administration of People’s Republic of China.
This standard is under the jurisdiction of SAC/TC 110/SC 1 the Subcommittee on Orthopaedic Implants of the National Technical Committee on Implants for Surgery and Orthopaedic Devices of Standardization Administration of China.
Implants for surgery - Partial and total hip joint prostheses -
Part 12: Deformation test method for acetabular shells
1 Scope
This part of YY/T 0809 specifies a test method for determining short-term deformation of a press-fit acetabular component for total hip joint replacement under specific laboratory conditions. It also defines the conditions of testing so that the important parameters that affect the components are taken into account and it describes how the specimen is set up for testing. Furthermore, this part specifies the test parameters of press-fit acetabular components tested in accordance with this part.
The test method is intended to be used to evaluate the comparison of various designs and materials used for acetabular components in total hip joint replacement when tested under similar conditions.
The loading of the acetabular components in vivo will, in general, differ from the loading defined in this test method. The results obtained here cannot be used to directly predict in vivo performance.
This part does not cover methods of examining the test specimen.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 12417.2 Non-active surgical implants - Osteosynthesis and joint replacement implants - Part 2: Particular requirements for joint replacement implants (GB/T 12417.2-2008, ISO 21534: 2002, IDT)
YY/T 0809.1 Implants for surgery - Partial and total hip joint prostheses - Part 1: Classification and designation of dimensions (YY/T 0809.1-2010, ISO 7206-1: 2008, IDT)
YY/T 0809.2 Implants for surgery - Partial and total hip joint prostheses - Part 2: Articulating surfaces made of metallic, ceramic and plastics materials (YY/T 0809.2-2010, ISO 7206-2: 1996, MOD)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in YY/T 0809.1, YY/T 0809.2 and GB/T 12417.2 and the following, apply.
3.1
metal backing deformation
amount of geometrical deviation (inner diameter and circularity of metal backing in a defined measurement plane) from design specifications under loading conditions
3.2
spherical socket deformation
articulating surface deformation
amount of geometrical deviation (diameter and circularity in a defined measurement plane) from design specifications under loading conditions
3.3
frontal face reference plane
plane, perpendicular to the component polar axis, nominally at the frontal face level (see Figure 1a))
Note 1: In case of doubt, the polar axis can be defined as a straight line perpendicular to the plane spanning around the contact zone of the acetabular component to the cortical bone, and passing through the centre point of the ball sphere approximating the acetabular component’s outer sphere.
Note 2: In case of an asymmetrically shaped front face, e.g. anatomically shaped acetabular components, the frontal face reference plane can be located at a level, which contains the largest part of the frontal face that is perpendicular to the component polar axis (see Figures 1b) and 1c)).
Note 3: In case the frontal face does not contain any part perpendicular to the component axis, the frontal face reference plane can be located at that level perpendicular to the polar axis at the approximated middle between the highest and the lowest point of the frontal face (see Figure 1d)).
Note: Marked (shaded) areas of the frontal face are located in the reference plane.
Figure 1 Frontal face reference plane of acetabular components
3.4
loading plane
plane, parallel to the frontal face reference plane and located in an area where the acetabular cup gets in contact with the cortical bone after being properly and fully seated intraoperatively
Example: For symmetrically shaped acetabular components, Figure 1a), the loading plane will usually be located close to the frontal face reference plane.
3.5
measurement plane
plane, parallel to the frontal face reference plane, located with a certain distance to the frontal face reference plane but as close as possible to the frontal face reference plane
Note 1: The sensitivity of the deformation measurement decreases with increasing distance of the measurement plane from the front face reference plane and with decreasing distance of the measurement plane to the top of the cup.
Note 2: Within the measurement plane, the measurement points for determining the inner diameter of the test specimen can be captured. Therefore, the measurement plane can be defined so that capturing the measurement points is not disturbed by any design features of the test specimen as holes or cut-outs. The measurement points can be captured at the test specimen directly; they cannot be captured at the load frame.
4 Principle
The test specimen is subjected to diametrically opposite two-point loading. For the determination of short-term deformation, measurements of diameter in loading direction in a defined measurement plane are carried out prior and under loading, as well as after unloading. This deformation measurement procedure is repeated two times after rotating the specimen with rotation angles of itself, of which each rotation angle measures 120° to account for influence of asymmetric design features as fins, holes, etc.
Metal-backed modular acetabular components can deform and affect the seating of the insert. The combination of metal-backing and insert can deform and affect the tribology. So such components shall be tested in two steps: first step, testing of the metal backing alone; second step, testing of the metal backing with the appropriately mounted bearing insert.
Press-fit installation of monoblock acetabular cup components can cause deformation of the articular surface which may affect tribology. Such components shall be tested in only one step.
5 Apparatus
5.1 Loading device
A load frame capable of the following functionality:
a) shall not exhibit any visible and irreversible deformation under loading the test specimen;
b) shall allow reproducible loading and unloading of a test specimen along a defined mechanical axis and measuring loads and distances, respectively;
c) shall be capable of loading acetabular cups up to a diameter of 100 mm and a height of 50 mm.
Foreword i 1 Scope 2 Normative references 3 Terms and definitions 4 Principle 5 Apparatus 6 Procedure 7 Report Bibliography
CS 11.040.40 C 35 YY 中华人民共和国医药行业标准 外科植入物 部分和全髋关节假体 第12部分：髋臼杯形变测试方法 Implants for surgery—Partial and total hip joint prostheses— Part 12：Deformation test method for acetabular shells (ISO 7206-12：2016，MOD)
说明： 1——导轨； 7——载荷调节螺栓； 2，3——固定横梁； 8——载荷传感器； 4，5——可移动横梁； 9——夹持／加载平面。 6——螺旋弹簧； 图3 加载装置原理图 加载过程中，夹持样品的夹爪应具有平整的夹持平面(平整度参见GB／T 1184)，避免样品在加载或测量过程中因倾斜或滑动产生侧向力。 某些髋臼部件的设计包括了一些具有特定目的设计元素，如复杂的翻修手术或病人的特殊需求，具体例如边缘锚定，符合解剖形态的边缘等。如果测试此类髋臼部件，应设计和使用合适的夹爪用于固定和加载试样。 夹持面的宽度应不低于测试样品前参照面外径的20％，这样在试验前可将试样接触点通过手动调整至夹持面的中心，而无需附加对中装置或工具。如果使用其他对中装置或工具，应确保两点载荷和试样的变形不会受到限制。 载荷传感器应能测量轴向压力且不确定度为1％。 5．2 试样选择 应随机选取被确定为最差情况型号的髋臼部件作为试样，其应能代表产品的生产制造，并与最终产品具有相同的几何结构，使用相同的材料规范和加工工艺。 注：对于组合式的髋臼部件，对于第一步试验(金属杯的变形)和第二步试验(髋臼部件关节面的变形)最差情况型号可能会不一样。 如果组合式髋臼部件使用了不同关节面材料，则应评估所有内衬的关节面材料和尺寸以确定其最差情况。同时也应考虑设计特征，例如不对称排列的螺钉孔。 6 试验步骤 a) 加载之前，用一种可行的测量装置在各个预期的加载方向测量试样内径D0[mm]。应测量位于测量平面上臼窝的内径，测量不确定度应小于5 μm。 此外，在同一个测量平面内可在其他位置测量直径，比如，在垂直于加载方向进行测量，以获取试样整体变形行为的补充数据。 b) 将试样置于试验装置上，平稳地旋转载荷调节螺栓以施加并保持(1.00±0.01)kN的轴向载荷。要避免不稳定的加载。试样与试验装置加载面的接触点应位于加载平面内。 c) 在a)中所述的同一测量平面内，用同一测量装置在加载方向测量试样的直径D1(mm)。髋臼杯的变形等于D0—D1。 d) 卸载。 e) 按c)中所述的测量方向，使用同一测量装置再次测量直径D0’[mm]。如果测得与a)中所得的初始直径的残差，D0’—D0，大于测量设备的不确定度，且测得大于c)中得到的变形的2％[(D0’—D0)／(D0—D0)＞0.02]，说明发生了塑性变形。在这种情况下，应停止测试该试样，使用下一个试样从a)开始进行试验。 f) 以部件极轴作为旋转中心，相对之前的位置把杯旋转120°，重复b)～e)步骤。仍以部件极轴作为旋转中心，相对之前的位置把杯再次旋转120°，重复b)～e)步骤。然后测试下一试样。 试验条件：组装和测量应在一致的实验室条件下进行。 试验样本数量至少为3件。对于不对称的样品，应确定参照方位。试验开始前相对该方位绕极轴的旋转角在不同试样问应变化。 除了仅在加载方向测量样品直径，也可以通过在适当的测量平面内评估试样直径和网度的差异来测定其变形。 某些罕见的髋臼部件设计为压配式整杯，它们由塑料制成，尽管其临床效果颇佳，但仍不能承受本标准规定的不产生不可逆损坏的载荷条件。在这种情况下，可以适当降低载荷。该类新设计髋臼杯系统与已有临床产品的对比也应使用小载荷的测试结果。 7 报告 试验报告应包含以下信息： a) 引用YY／T 0809本部分的内容； b) 髋臼杯所有部件的特征及描述，应与委托检测试样的一方所陈述的一致，以及制造商名称和所列参考文献； c) 每种最差情况的设计、尺寸、材料组合(如适用)的髋臼部件(如杯、内衬)的尺寸及公差； d) 与髋臼部件设计规范的偏离； e) 试验装置的材料和刚度，如螺旋弹簧的材料和刚度； f) 针对非对称杯边缘设计，如图1b)～图1d)所示，描述在装置中加载时臼杯的方位，以给出臼杯和加载平面的接触信息，如拍摄照片； g) 针对非对称杯边缘设计，如图1b)～图1d)所示，描述如何定义极轴； h) 针对非对称杯边缘设计，如图1b)～图1d)所示，描述如何针对试样设计定义前参照平面； i) 从测量平面到前参照平面的距离，以及测量平面相对于前参照平面(远端／近端)如何定位； j) 加载时，对应于每一个最差情况的结构(如杯、杯／内衬组合)、设计、尺寸和材料组合所测试的范围和平均变形(标准偏差)(直径，其他测量结果)； k) 卸载后，对应于每一个最差情况的结构(如杯、杯／内衬组合)、设计、尺寸和材料组合所测试的范围和平均塑性变形(标准偏差)(直径，其他测量结果)； l) 测量装置的规范(直径测量)； m) 任何因测试方法造成的偏差。 参考文献 [1] GB／T 1184 形状和位置公差 未注公差值(GB／T 1184—1996，ISO 2768-2：1989，EQV) [2] PostakP．D．，RoscaM．，GreenwaldA．S．Do thin acetabular shells increase the disassociation risk of ceramic liners? J．Bone Joint Surg．Am．2009，91 pp．129-133 [3] LiuF．，JinZ．M．，RobertsP．，GrigorisP．Importance of head diameter，clearance，and cup wall thickness in elastohydrodynamic lubrication analysis of metal-on-metal hip resurfacing prostheses．Proc．Inst．Mech Eng．H．2006，220(6) pp．695-704 [4] SquireM．，Griffinw．L．，MasonJ．B．，PeindlR．D．，OdumS．Acetabular cornPonent deformation with press fit fixation．J Arthr．2006，21(6，) pp．72-77 [5] SchmidigG．，PatelA．，LiepinsI．，ThakoreM．，MarkelD．C．The effects of acetabular shell deformation and liner thickness on frictional torque in ultrahigh-molecular-weight polyethylene acetabular bearings．J Arthr．2010，25(4) pp．644-653 [6] GrimesJ．B．Reclassification of metal-metal bearings based on operational clearance．56th Ann Meet ORS (Poster 2277)，March 6-9，New Orleans，2010 [7] TsaiS．，＆ PawarV．A bi-layer foam block model to evaluate deformation of a modular metal-onmetal acetabular liner design．56th Ann Meet ORS (Poster 2026)，March 6-9，New Orleans，2010 [8] BishopN．，＆ MorlockM．M．The risk of acetabular cup turn out due to joint friction moments．56th Ann Meet ORS (Poster 2025)，March 6-9，New Orleans，2010 [9] JinZ．M．，MeakinsS．，MorlockM．M．，ParsonsP．，HardakerC．，FlettM．，IsaacG． Deformation of press-fitted metallic resurfacing cups—Part 1：Experimental simulation．Proc．Inst．Mech Eng．H．2006，220(2) pp．299-309 [10] FritscheA．，BialekK．，MittelmeierW．，SimnacherM．，FethkeK．，WreeA．，BaderR．Experimental investigations of the insertion and deformation behaviour of press-fit and threaded cupS for total hip replacement．J．Orthop．Sci．2008，13(3)pp．240-247 [11] Hogg M．C．，& GilliesR．M．Impaction of a press-fit acetabular cup using a dynamic finite element [12] Hogg M．C．，＆ Gillies R．M．Impaction of a typical press-fit modular acetabular cup using a dynamic finite element method．56th Ann Meet ORS(Poster 2105)，March 6-9，New Orleans，2010 [13] HothanA．，HuberG．，WeissC．，HoffmannN．，MorlockM．M．Deformation characteristics and eigenfrequencies of press-fit acetabular cups．Clin．Biomech．(Bristol，Avon)．2011，26(1) pp．46-51
