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.
This standard is developed in accordance with the rules given in GB/T 1.1-2009.
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 standard 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.
Standard test method for evaluating tibial insert endurance and deformation under high flexion
1 Scope
This standard specifies a test method for determining the endurance properties and deformation, under specified laboratory conditions, of ultra high molecular weight polyethylene (UHMWPE) tibial bearing components used in bicompartmental or tricompartmental knee prosthesis designs.
This standard applies to bearing components manufactured from UHMWPE.
Note: This test method could be adapted to address unicompartmental total knee replacement (TKR) systems, provided that the designs of the unicompartmental systems have sufficient constraint to allow use of this test method.
This test method does not include instructions for testing two unicompartmental knees as a bicompartmental system.
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.
YY/T 0772.3 Implants for surgery - Ultra-high-molecular-weight polyethylene - Part 3: Accelerated ageing methods
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
anatomic (mechanical) axis of femur
the line between the center of the femoral head and the center of the femoral knee
3.2
bearing centerline
the line running anteroposterior that is the mirror line of the femoral articulating surface
Note: For asymmetric bearing tibial tray designs, the appropriate tibial tray centerline shall be determined and reported along with the rationale for the location.
3.3
bearing retention mechanism
mechanical means for preventing tibial tray/bearing disassociation
3.4
femoral component centerline
a line running anteroposterior between the femoral condyles and parallel to the femoral condyles
Note: The line should be equidistant between the condyles. For asymmetric or non-parallel condyles designs, the appropriate centerline shall be determined.
3.5
fixed bearing system
a knee prosthesis system comprised of a femoral component and a tibial component, where the tibial articulating surface is not intended to move relative to the tibial tray
3.6
mobile bearing
the component between fixed femoral and tibial knee components with an articulating surface on both the inferior and superior sides
3.7
mobile bearing knee system
a knee prosthesis system comprised of a femoral component, a tibial component, and a mobile bearing component that can rotate and/or translate relative to the tibial component
3.8
tibial axis
nominal longitudinal axis of the tibia, which corresponds with the central axis of the medullary cavity of the proximal tibia
3.9
posterior slope
the angle that the perpendicular axis of the tibial tray makes when it is tilted posteriorly away from the tibial axis (see Figure 1)
3.10
R value
the ratio of the minimum force to the maximum force (that is, R = minimum force/maximum force)
3.11
tibial tray-bearing disassociation
unrecoverable physical separation of the tibial bearing and tibial tray components as a result of bearing distraction or tilting
3.12
tibial tray centerline
a line running anteroposterior that is the mirror line of the tibial articulating surface
Note: For asymmetric bearing tibial tray designs, the appropriate tibial tray centerline shall be determined and reported along with the rationale for the location.
Figure 1 Incline of the tibial tray relative to the tibial axis at the recommended angle (posterior slope)
4 Significance and use
4.1 This test method is intended to simulate near posterior edge loading similar to the type of loading that would occur during high flexion motions such as squatting or kneeling.
4.2 Although the methodology described attempts to identify physiological orientations and loading conditions, the interpretation of results is limited to an in vitro comparison between knee prosthesis designs and their ability to resist deformation and fracture under stated test conditions.
4.3 This test method can be used to describe the effects of materials, manufacturing, and design variables on the fatigue/ cyclic creep performance of UHMWPE bearing components subject to substantial rotation in the transverse plane (relative to the tibial tray) for a relatively large number of cycles.
4.4 The loading and kinematics of bearing component designs in vivo will, in general, differ from the loading and kinematics defined in this test method. The results obtained here cannot be used to directly predict in vivo performance. However, this test method is designed to enable comparisons between the fatigue performance of different bearing component designs when tested under similar conditions.
4.5 The test described is applicable to any bicompartmental knee design including mobile bearing knees that have mechanisms in the tibial articulating component to constrain the posterior movement of the femoral component and a built-in retention mechanism to keep the articulating component on the tibial plate.
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Significance and use
5 Apparatus and materials
6 Specimen selection
7 Test procedures
8 Reporting results
Annex A (Informative) Basic principles
Bibliography
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.
This standard is developed in accordance with the rules given in GB/T 1.1-2009.
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 standard 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.
Standard test method for evaluating tibial insert endurance and deformation under high flexion
1 Scope
This standard specifies a test method for determining the endurance properties and deformation, under specified laboratory conditions, of ultra high molecular weight polyethylene (UHMWPE) tibial bearing components used in bicompartmental or tricompartmental knee prosthesis designs.
This standard applies to bearing components manufactured from UHMWPE.
Note: This test method could be adapted to address unicompartmental total knee replacement (TKR) systems, provided that the designs of the unicompartmental systems have sufficient constraint to allow use of this test method.
This test method does not include instructions for testing two unicompartmental knees as a bicompartmental system.
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.
YY/T 0772.3 Implants for surgery - Ultra-high-molecular-weight polyethylene - Part 3: Accelerated ageing methods
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
anatomic (mechanical) axis of femur
the line between the center of the femoral head and the center of the femoral knee
3.2
bearing centerline
the line running anteroposterior that is the mirror line of the femoral articulating surface
Note: For asymmetric bearing tibial tray designs, the appropriate tibial tray centerline shall be determined and reported along with the rationale for the location.
3.3
bearing retention mechanism
mechanical means for preventing tibial tray/bearing disassociation
3.4
femoral component centerline
a line running anteroposterior between the femoral condyles and parallel to the femoral condyles
Note: The line should be equidistant between the condyles. For asymmetric or non-parallel condyles designs, the appropriate centerline shall be determined.
3.5
fixed bearing system
a knee prosthesis system comprised of a femoral component and a tibial component, where the tibial articulating surface is not intended to move relative to the tibial tray
3.6
mobile bearing
the component between fixed femoral and tibial knee components with an articulating surface on both the inferior and superior sides
3.7
mobile bearing knee system
a knee prosthesis system comprised of a femoral component, a tibial component, and a mobile bearing component that can rotate and/or translate relative to the tibial component
3.8
tibial axis
nominal longitudinal axis of the tibia, which corresponds with the central axis of the medullary cavity of the proximal tibia
3.9
posterior slope
the angle that the perpendicular axis of the tibial tray makes when it is tilted posteriorly away from the tibial axis (see Figure 1)
3.10
R value
the ratio of the minimum force to the maximum force (that is, R = minimum force/maximum force)
3.11
tibial tray-bearing disassociation
unrecoverable physical separation of the tibial bearing and tibial tray components as a result of bearing distraction or tilting
3.12
tibial tray centerline
a line running anteroposterior that is the mirror line of the tibial articulating surface
Note: For asymmetric bearing tibial tray designs, the appropriate tibial tray centerline shall be determined and reported along with the rationale for the location.
Figure 1 Incline of the tibial tray relative to the tibial axis at the recommended angle (posterior slope)
4 Significance and use
4.1 This test method is intended to simulate near posterior edge loading similar to the type of loading that would occur during high flexion motions such as squatting or kneeling.
4.2 Although the methodology described attempts to identify physiological orientations and loading conditions, the interpretation of results is limited to an in vitro comparison between knee prosthesis designs and their ability to resist deformation and fracture under stated test conditions.
4.3 This test method can be used to describe the effects of materials, manufacturing, and design variables on the fatigue/ cyclic creep performance of UHMWPE bearing components subject to substantial rotation in the transverse plane (relative to the tibial tray) for a relatively large number of cycles.
4.4 The loading and kinematics of bearing component designs in vivo will, in general, differ from the loading and kinematics defined in this test method. The results obtained here cannot be used to directly predict in vivo performance. However, this test method is designed to enable comparisons between the fatigue performance of different bearing component designs when tested under similar conditions.
4.5 The test described is applicable to any bicompartmental knee design including mobile bearing knees that have mechanisms in the tibial articulating component to constrain the posterior movement of the femoral component and a built-in retention mechanism to keep the articulating component on the tibial plate.
Contents of YY/T 1736-2020
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Significance and use
5 Apparatus and materials
6 Specimen selection
7 Test procedures
8 Reporting results
Annex A (Informative) Basic principles
Bibliography
