ISO 21536:2023
(Main)Non-active surgical implants — Joint replacement implants — Specific requirements for knee-joint replacement implants
Non-active surgical implants — Joint replacement implants — Specific requirements for knee-joint replacement implants
This document specifies requirements for knee-joint replacement implants. Regarding safety, this document specifies requirements for intended performance, design attributes, materials, design evaluation, manufacture, sterilization, packaging, information supplied by the manufacturer and methods of test. This document applies to both total and partial knee joint replacement implants. It applies to these replacements both with and without the replacement of the patella-femoral joint. It applies to components made of metallic and non-metallic materials. This document applies to a wide variety of knee replacement implants, but for some specific knee replacement implant types, some considerations, not specifically covered in this document, can be applicable. Further details are given in 7.2.1.2. The requirements which are specified in this document are not intended to require the re-design or re-testing of implants which have been legally marketed and for which there is a history of sufficient and safe clinical use. For such implants, compliance with this document can be demonstrated by providing evidence of the implant’s sufficient and safe clinical use.
Implants chirurgicaux non actifs — Implants de remplacement d'articulation — Exigences spécifiques relatives aux implants de remplacement de l'articulation du genou
Le présent document spécifie les exigences relatives aux prothèses de l'articulation du genou. En matière de sécurité, le présent document fournit des exigences relatives aux performances prévues, à la conception, aux matériaux, à l'évaluation de la conception, à la fabrication, à la stérilisation, à l'emballage et aux informations devant être fournies par le fabricant ainsi que des méthodes d'essai. Le présent document s'applique à la fois aux implants de remplacement total et partiel de l'articulation du genou. Il s'applique à ces remplacements avec et sans remplacement de l'articulation fémoro-patellaire. Il s'applique aux composants fabriqués en matériaux métalliques et non métalliques. Le présent document s'applique à une grande variété d'implants, mais certaines considérations, non spécifiquement couvertes dans le présent document, peuvent être applicables à certains types spécifiques d'implants de remplacement de l'articulation du genou. Voir 7.2.1.2 pour plus de détails. Les exigences spécifiées dans le présent document n'ont pas pour but d'exiger une nouvelle conception ou de nouveaux essais sur des implants qui ont été légalement mis sur le marché et pour lesquels il existe un historique d'utilisation clinique suffisante et sans danger. Pour ces implants, la conformité au présent document peut être démontrée en fournissant la preuve d'une utilisation clinique suffisante et sans danger de l'implant.
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INTERNATIONAL ISO
STANDARD 21536
Third edition
2023-07
Non-active surgical implants —
Joint replacement implants —
Specific requirements for knee-joint
replacement implants
Implants chirurgicaux non actifs — Implants de remplacement
d'articulation — Exigences spécifiques relatives aux implants de
remplacement de l'articulation du genou
Reference number
ISO 21536:2023(E)
© ISO 2023
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ISO 21536:2023(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2023
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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Published in Switzerland
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ISO 21536:2023(E)
Contents Page
Foreword .iv
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Intended performance .6
5 Design attributes .6
5.1 General . 6
5.2 Tolerances and dimensions . 7
5.2.1 Tolerances and dimensions of taper connections . 7
5.2.2 Surface finish of non-articulating regions of knee joint components . 8
5.2.3 Surface finish of articulating surfaces of knee joint components . 8
5.3 Thickness of knee joint components . 8
5.3.1 General . 8
5.3.2 Thickness of UHMWPE in tibial inserts, monobloc tibial components,
mobile-bearing components, patella inserts and monobloc patellar
components . 8
5.3.3 Thickness of metal and ceramic in femoral components, tibial trays and
patellar trays . . . 9
6 Materials .10
7 Design evaluation .10
7.1 General . 10
7.2 Pre-clinical evaluation . . 10
7.2.1 General . 10
7.2.2 Test methods and performance requirements .12
7.3 Clinical investigation . 18
7.4 Post market surveillance . 19
8 Manufacture .19
9 Sterilization .19
10 Packaging.19
11 Information to be supplied by the manufacturer .19
11.1 General . 19
11.2 Product type and dimensions . 19
11.3 Constructional and functional compatibility of components . 20
11.4 Marking . 20
11.5 Information for the patient . 20
11.6 Electronic instructions for use . 20
Annex A (informative) Evaluation of the range of relative angular motion of components of
fully constrained total knee joint replacement implants .21
Bibliography .22
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ISO 21536:2023(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO document should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use
of (a) patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed
patent rights in respect thereof. As of the date of publication of this document, ISO had not received
notice of (a) patent(s) which may be required to implement this document. However, implementers are
cautioned that this may not represent the latest information, which may be obtained from the patent
database available at www.iso.org/patents. ISO shall not be held responsible for identifying any or all
such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 150, Implants for surgery, Subcommittee
SC 4, Bone and joint replacements, in collaboration with the European Committee for Standardization
(CEN) Technical Committee CEN/TC 285, Non-active surgical implants, in accordance with the Agreement
on technical cooperation between ISO and CEN (Vienna Agreement).
This third edition cancels and replaces the second edition (ISO 21536:2007), which has been technically
revised. It also incorporates the Amendment ISO 21536:2007/Amd 1:2014.
The main changes are as follows:
— The scope has been expanded to specify more precisely the knee joint replacement types which are
the subject of this document. Also, the scope now clarifies the requirements for implants which have
been legally marketed and for which there is a history of sufficient and safe clinical use.
— The number of normative references has been expanded, including the addition of several ASTM
standards.
— Several new definitions have been added, including: maximum claimed flexion, mobile-bearing
component, mobile-bearing knee joint prosthesis, partial knee joint prosthesis and partial knee
joint replacement, posterior stabilized tibial insert, reference implant, sufficient and safe clinical
use, tibial insert, total knee joint prosthesis and total knee joint replacement, ultra-high molecular
weight polyethylene and UHMWPE, uni-compartmental knee joint replacement and UKR, and worst
case.
— The design attributes to be taken into account have been specified in Clause 5. The requirements
for the thickness of various knee joint components made from plastic, metal and ceramic have been
expanded.
— Several new general requirements have been added in 7.2.1, which specify
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ISO 21536:2023(E)
a) the circumstances when a test can be omitted,
b) the testing of the worst case,
c) the processes to be followed when no performance requirement has been specified, and
d) the processes to be followed when a performance requirement has been specified but has not
been met.
— The number of pre-clinical evaluations (bench tests) to be performed has been greatly increased
in 7.2.2. For some of the tests, a performance requirement has been specified. For some of the
tests, no performance requirement has been specified and, in these cases, a new requirement has
been added, namely the requirement to demonstrate that the performance of the implant under
evaluation is the same or better than that of a reference implant. If no reference implant exists, a
sequence of alternative options has been specified. These alternative options are also available in
the case where there is a performance requirement, which is not met by the implant being tested.
— A new clinical investigation subclause has been added in 7.3, with several requirements which
specify the circumstances in which a clinical investigation can be required.
— A new post-market surveillance subclause has been added in 7.4, which references the requirements
in ISO 21534:2007, 7.4.
— Several new marking requirements have been specified in 11.4.
— A note has been added in 11.6 which states that in some jurisdictions there is the option to provide
the instructions for use in electronic instead of paper format.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
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ISO 21536:2023(E)
Introduction
There are three levels of standards dealing with non-active surgical implants. These are as follows,
with level 1 being the highest:
— level 1: general requirements for non-active surgical implants and instrumentation used in
association with implants;
— level 2: particular requirements for families of non-active surgical implants;
— level 3: specific requirements for types of non-active surgical implant.
This document is a level 3 standard and contains requirements applying specifically to knee joint
replacements.
The level 1 standard, ISO 14630, contains requirements that apply to all non-active surgical implants. It
also indicates that there are additional requirements in the level 2 and level 3 standards.
The level 2 standards apply to more restricted sets or families of implants such as those designed for
use in osteosynthesis, cardiovascular surgery or joint replacement. For joint replacement implants, the
level 2 standard is ISO 21534.
To address all requirements, it is recommended that a standard of the lowest available level be consulted
first.
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INTERNATIONAL STANDARD ISO 21536:2023(E)
Non-active surgical implants — Joint replacement implants
— Specific requirements for knee-joint replacement
implants
1 Scope
This document specifies requirements for knee-joint replacement implants. Regarding safety, this
document specifies requirements for intended performance, design attributes, materials, design
evaluation, manufacture, sterilization, packaging, information supplied by the manufacturer and
methods of test.
This document applies to both total and partial knee joint replacement implants. It applies to these
replacements both with and without the replacement of the patella-femoral joint. It applies to
components made of metallic and non-metallic materials.
This document applies to a wide variety of knee replacement implants, but for some specific knee
replacement implant types, some considerations, not specifically covered in this document, can be
applicable. Further details are given in 7.2.1.2.
The requirements which are specified in this document are not intended to require the re-design or re-
testing of implants which have been legally marketed and for which there is a history of sufficient and
safe clinical use. For such implants, compliance with this document can be demonstrated by providing
evidence of the implant’s sufficient and safe clinical use.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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.
ISO 5834-1, Implants for surgery — Ultra-high-molecular-weight polyethylene — Part 1: Powder form
ISO 7207-1:2007, Implants for surgery — Components for partial and total knee joint prostheses — Part 1:
Classification, definitions and designation of dimensions
ISO 7207-2, Implants for surgery — Components for partial and total knee joint prostheses — Part 2:
Articulating surfaces made of metal, ceramic and plastics materials
ISO 10993-1, Biological evaluation of medical devices — Part 1: Evaluation and testing within a risk
management process
ISO 14243-1, Implants for surgery — Wear of total knee-joint prostheses — Part 1: Loading and
displacement parameters for wear-testing machines with load control and corresponding environmental
conditions for test
ISO 14243-2, Implants for surgery — Wear of total knee-joint prostheses — Part 2: Methods of measurement
ISO 14243-3, Implants for surgery — Wear of total knee-joint prostheses — Part 3: Loading and
displacement parameters for wear-testing machines with displacement control and corresponding
environmental conditions for test
ISO 14243-5, Implants for surgery — Wear of total knee prostheses — Part 5: Durability performance of
the patellofemoral joint
ISO 14630, Non-active surgical implants — General requirements
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ISO 21536:2023(E)
ISO 14879-1, Implants for surgery — Total knee-joint prostheses — Part 1: Determination of endurance
properties of knee tibial trays
ISO 21534:2007, Non-active surgical implants — Joint replacement implants — Particular requirements
ASTM F648, Standard Specification for Ultra-High-Molecular-Weight Polyethylene Powder and Fabricated
Form for Surgical Implants
ASTM F1223, Standard Test Method for Determination of Total Knee Replacement Constraint
ASTM F2722, Standard Practice for Evaluating Mobile Bearing Knee Tibial Baseplate Rotational Stops
ASTM F2723, Standard Test Method for Evaluating Mobile Bearing Knee Tibial Baseplate/Bearing
Resistance to Dynamic Disassociation
ASTM F2724, Standard Test Method for Evaluating Mobile Bearing Knee Dislocation
ASTM F2777, Standard Test Method for Evaluating Knee Bearing (Tibial Insert) Endurance and Deformation
Under High Flexion
ASTM F3210, Standard Test Method for Fatigue Testing of Total Knee Femoral Components under Closing
Conditions
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 7207-1, ISO 14630, ISO 21534
and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
femoral component
component of a total knee joint prosthesis (3.14), patella-femoral knee joint prosthesis or uni-
compartmental knee joint prosthesis (3.16) intended to be secured to the femur to replace its articulating
surface(s)
3.2
maximum claimed flexion
highest amount of flexion the total knee joint prosthesis (3.14) or uni-compartmental knee joint prosthesis
(3.16) can achieve as claimed by the manufacturer based on the requirements defined in 7.2.2.11
Note 1 to entry: A higher amount of flexion than the maximum claimed flexion can exist based on computer aided
design (CAD) or implant shape considerations.
3.3
mobile-bearing component
component of a total or uni-compartmental mobile-bearing knee joint prosthesis (3.4) which articulates
with both the femoral component (3.1) and the tibial tray (3.13)
Note 1 to entry: The mobile-bearing component can be manufactured as one component or a set of components,
in both cases intended to be assembled in the mobile-bearing knee joint prosthesis (3.4) by the user.
Note 2 to entry: The mobile-bearing component is usually a sub-component of the tibial component (3.11),
supported by the tibial tray (3.13).
Note 3 to entry: The mobile-bearing component can also be referred to as the meniscal component.
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ISO 21536:2023(E)
[SOURCE: ISO 7207-1:2007, 3.2.10, modified — Note 1 to entry has been replaced and Notes 2 and 3 to
entry have been added.]
3.4
mobile-bearing knee joint prosthesis
total knee joint prosthesis (3.14) or uni-compartmental knee joint prosthesis (3.16) which allows relative
motion between the mobile-bearing component (3.3) and both the femoral component (3.1) and the tibial
tray (3.13)
[SOURCE: ISO 7207-1:2007, 3.1.6, modified — "knee joint prosthesis" has been added after "total" in the
definition and Note 1 to entry has been deleted.]
3.5
partial knee joint prosthesis
partial knee joint replacement
uni-compartmental knee joint prosthesis (3.16) or a set of components used to replace the femoral and
tibial articulating surfaces in the medial compartment of a knee joint and also the patellar and femoral
articulating surfaces in the patella-femoral compartment
Note 1 to entry: Implants which are intended to repair a cartilage focal defect(s) or to be used for a surgical
procedure like mosaicplasty are not partial knee joint prostheses for the purposes of this document.
3.6
patellar component
component of a total knee joint prosthesis (3.14) or partial knee joint prosthesis (3.5) or patella-femoral
knee joint prosthesis which is used to replace the articulating surface of the patella
Note 1 to entry: Patellar components can be monobloc or modular.
3.7
patellar tray
sub-component of a modular patellar component (3.6) of a total knee joint prosthesis (3.14), a partial knee
joint prosthesis (3.5) or a patella-femoral knee joint prosthesis, used to support and secure the patellar
insert
[SOURCE: ISO 7207-1:2007, 3.2.14, modified — "a partial knee joint prosthesis (3.5) or a patella-femoral
knee joint prosthesis" has been added to the definition.]
3.8
posterior stabilized tibial insert
tibial insert (3.12) with a centre post protruding superiorly or some other mechanism which interfaces
with the femoral component (3.1) to restrict anterior translation of the femoral component when the
knee is in flexion
Note 1 to entry: The portion of the femoral component interfacing with the tibial insert centre post is sometimes
referred to as the “cam”.
3.9
reference implant
legally-marketed implant which, when compared to the implant under evaluation, satisfies both of the
following conditions:
a) it has the same intended use, similar materials and a similar design with regard to the specific
dimensional or performance criteria under evaluation to address the same clinical and technical
requirements, and
b) there is evidence of successful clinical use in sufficient numbers; for a sufficient period of time; and,
at a minimum, without known or reasonably-known evidence of design or performance-related
recalls with regard to the specific dimensional or performance criteria under evaluation
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ISO 21536:2023(E)
Note 1 to entry: The term “reference” is not intended to imply that the implant under evaluation and the
reference implant are “equivalent” or that the reference implant is a “predicate” implant. This is because for some
regulatory authorities, the terms “equivalent” and “predicate” have a meaning which is beyond that intended by
the term “reference” as used in this document.
Note 2 to entry: A reference implant is the comparison implant for dimensional or performance parameter(s)
under evaluation. Other characteristics of the reference implant shall be considered in order for the comparison
to be suitable, as in some situations there can be cross-effects. Ideally, for the majority of dimensional and
performance parameters, a single reference implant should be used for comparison to the implant under
evaluation. However, more than one reference implant may be used for comparison purposes, with adequate
scientific and clinical justification.
Note 3 to entry: Some regulatory authorities require that a reference implant is one that is legally marketed in
their own country or jurisdiction. This fact can be taken into account when selecting a reference implant for the
purposes of this document.
Note 4 to entry: There is no agreed upon interpretation for what constitutes “sufficient numbers” or a “sufficient
period of time” in the above definition. Typically, a determination of what constitutes “sufficient numbers” and a
“sufficient period of time” is demonstrated by using statistical methods and clinical judgement in the evaluation
of implant performance.
Note 5 to entry: A justification for a “similar material” may include information that although the materials are
not the same, the material(s) used for the implant under evaluation can be shown to perform similarly with
regard to the test or its underlying clinical concern.
Note 6 to entry: Examples of design features that can be taken into consideration when evaluating whether an
implant has a ‘similar design’ to the implant under evaluation include means of fixation, modularity, constraint,
key dimensions and shape, processing, surface topography, surface treatment, etc. A justification for a “similar
design” therefore may include information that although the designs are not the same, the design of the implant
under evaluation can be shown to perform similarly with regard to the test or its underlying clinical concern.
Note 7 to entry: The manufacturer is responsible for identifying the reference implant(s) according to the
regulatory requirements in the jurisdictions where the implant under evaluation is to be marketed.
3.10
sufficient and safe clinical use
clinical use of a legally-marketed implant in sufficient numbers, for a sufficient period of time and, at a
minimum, without known or reasonably-known evidence of design or performance-related recalls
Note 1 to entry: There is no agreed interpretation for what constitutes “sufficient numbers” or “sufficient period
of time” in the above definition. Typically, these are demonstrated by using statistical methods and clinical
judgement in the evaluation of implant performance.
Note 2 to entry: Some regulatory authorities can require that a legally-marketed implant is one which is legally
marketed in their country or jurisdiction.
Note 3 to entry: For a legally-marketed system of knee replacement implants, there can be evidence to
demonstrate sufficient and safe clinical use for some parts of the system (e.g. some components and some sizes)
but not for others. For those parts of the system for which there is sufficient evidence, the requirements of this
document relating to design and testing shall not apply. For those parts of the system for which there is not
sufficient evidence to demonstrate sufficient and safe clinical use the requirements of this document relating to
design and testing shall apply.
Note 4 to entry: The manufacturer is responsible for identifying the implant with sufficient and safe clinical use
according to the regulatory requirements in the jurisdictions where the implant is to be marketed.
3.11
tibial component
component of a total knee joint prosthesis (3.14) or uni-compartmental knee joint prosthesis (3.16)
intended to be secured to the tibia to replace its articulating surface(s)
Note 1 to entry: Tibial components can be monobloc or modular. When modular, the tibial component usually
consists either of a tibial insert (3.12) or a mobile-bearing component (3.3), and a tibial tray (3.13).
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ISO 21536:2023(E)
[SOURCE: ISO 7207-1:2007, 3.2.5, modified — "knee joint prosthesis" has been added after "total" in the
definition and a second sentence has been added to Note 1 to entry.]
3.12
tibial insert
sub-component of a modular tibial component (3.11) of a total knee joint prosthesis (3.14) or uni-
compartmental knee joint prosthesis (3.16) which is attached to the tibial tray (3.13) and which
articulates with the femoral component (3.1)
[SOURCE: ISO 7207-1:2007, 3.2.9, modified — "knee joint prosthesis" has been added after "total" in the
definition and Note 1 to entry has been deleted.]
3.13
tibial tray
sub-component of a modular tibial component (3.11) of a total knee joint prosthesis (3.14) or uni-
compartmental knee joint prosthesis (3.16) used to support the tibial insert (3.12) or mobile-bearing
component (3.3)
Note 1 to entry: The tibial tray is also referred to as the tibial baseplate.
Note 2 to entry: The central stem or other prominence o
...
NORME ISO
INTERNATIONALE 21536
Troisième édition
2023-07
Implants chirurgicaux non actifs —
Implants de remplacement
d'articulation — Exigences
spécifiques relatives aux implants de
remplacement de l'articulation du
genou
Non-active surgical implants — Joint replacement implants —
Specific requirements for knee-joint replacement implants
Numéro de référence
ISO 21536:2023(F)
© ISO 2023
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ISO 21536:2023(F)
DOCUMENT PROTÉGÉ PAR COPYRIGHT
© ISO 2023
Tous droits réservés. Sauf prescription différente ou nécessité dans le contexte de sa mise en œuvre, aucune partie de cette
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ISO 21536:2023(F)
Sommaire Page
Avant-propos .iv
Introduction . vi
1 Domaine d'application .1
2 Références normatives .1
3 Termes et définitions . 2
4 Performances prévues . 6
5 Attributs de conception .7
5.1 Généralités . 7
5.2 Tolérances et dimensions . 8
5.2.1 Tolérances et dimensions des raccordements coniques . 8
5.2.2 État de surface pour les régions non articulaires des composants des
prothèses de l'articulation du genou . 8
5.2.3 État de surface pour les surfaces articulaires des composants de prothèses
de l'articulation du genou . 8
5.3 Épaisseur des composants de prothèses de l'articulation du genou . 9
5.3.1 Généralités . 9
5.3.2 Épaisseur du PE-UHMW dans les inserts tibiaux, les éléments tibiaux
monoblocs, les éléments articulaires mobiles, les inserts rotuliens et les
éléments rotuliens monoblocs . 9
5.3.3 Épaisseur du métal et de la céramique dans les composants fémoraux, les
plateaux tibiaux et les composants de soutien rotuliens . 10
6 Matériaux .10
7 Évaluation de la conception .11
7.1 Généralités . 11
7.2 Évaluation préclinique . 11
7.2.1 Généralités . 11
7.2.2 Méthodes d'essai et exigences relatives à la performance .13
7.3 Investigation clinique . 20
7.4 Surveillance après mise sur le marché. 20
8 Fabrication .20
9 Stérilisation .20
10 Emballage .20
11 Informations à fournir par le fabricant .21
11.1 Généralités . 21
11.2 Type et dimensions du produit . 21
11.3 Compatibilité structurelle et fonctionnelle des composants . 21
11.4 Marquage . 21
11.5 Informations à fournir au patient . 22
11.6 Instructions d'utilisation au format électronique . 22
Annexe A (Informative) Évaluation de l'amplitude de mouvement angulaire relatif des
composants d'un implant de remplacement total avec contrainte de l'articulation
du genou .23
Bibliographie .24
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ISO 21536:2023(F)
Avant-propos
L'ISO (Organisation internationale de normalisation) est une fédération mondiale d'organismes
nationaux de normalisation (comités membres de l'ISO). L'élaboration des Normes internationales est
en général confiée aux comités techniques de l'ISO. Chaque comité membre intéressé par une étude
a le droit de faire partie du comité technique créé à cet effet. Les organisations internationales,
gouvernementales et non gouvernementales, en liaison avec l'ISO participent également aux travaux.
L'ISO collabore étroitement avec la Commission électrotechnique internationale (IEC) en ce qui
concerne la normalisation électrotechnique.
Les procédures utilisées pour élaborer le présent document et celles destinées à sa mise à jour sont
décrites dans les Directives ISO/IEC, Partie 1. Il convient, en particulier, de prendre note des différents
critères d'approbation requis pour les différents types de documents ISO. Le présent document a
été rédigé conformément aux règles de rédaction données dans les Directives ISO/IEC, Partie 2 (voir
www.iso.org/directives).
L’ISO attire l’attention sur le fait que la mise en application du présent document peut entraîner
l’utilisation d’un ou de plusieurs brevets. L’ISO ne prend pas position quant à la preuve, à la validité
et à l’applicabilité de tout droit de brevet revendiqué à cet égard. À la date de publication du présent
document, l’ISO n'avait pas reçu notification qu’un ou plusieurs brevets pouvaient être nécessaires à sa
mise en application. Toutefois, il y a lieu d’avertir les responsables de la mise en application du présent
document que des informations plus récentes sont susceptibles de figurer dans la base de données de
brevets, disponible à l'adresse www.iso.org/brevets. L’ISO ne saurait être tenue pour responsable de ne
pas avoir identifié tout ou partie de tels droits de propriété.
Les appellations commerciales éventuellement mentionnées dans le présent document sont données
pour information, par souci de commodité, à l’intention des utilisateurs et ne sauraient constituer un
engagement.
Pour une explication de la nature volontaire des normes, la signification des termes et expressions
spécifiques de l'ISO liés à l'évaluation de la conformité, ou pour toute information au sujet de l'adhésion
de l'ISO aux principes de l’Organisation mondiale du commerce (OMC) concernant les obstacles
techniques au commerce (OTC), voir www.iso.org/avant-propos.
Le présent document a été élaboré par le comité technique ISO/TC 150, Implants chirurgicaux, sous-
comité SC 4, Prothèses des os et des articulations, en collaboration avec le comité technique CEN/TC 285,
Implants chirurgicaux non actifs, du Comité européen de normalisation (CEN), conformément à l'Accord
de coopération technique entre l'ISO et le CEN (Accord de Vienne).
Cette troisième édition annule et remplace la deuxième édition (ISO 21536:2007), qui a fait l'objet d'une
révision technique. Elle incorpore également l'Amendement ISO 21536:2007/Amd 1:2014.
Les principales modifications sont les suivantes:
— le domaine d'application a été élargi pour spécifier plus précisément les types de prothèses de
l'articulation du genou qui sont traités dans le présent document. En outre, le domaine d'application
clarifie désormais les exigences relatives aux implants qui ont été légalement mis sur le marché et
pour lesquels il existe un historique d'utilisation clinique suffisante et sans danger;
— le nombre de références normatives a été élargi, notamment par l'ajout de plusieurs normes ASTM;
— plusieurs nouvelles définitions ont été ajoutées, y compris les suivantes: flexion maximale
revendiquée, insert mobile, prothèse articulaire mobile de l'articulation du genou, prothèse partielle
de l'articulation du genou et remplacement partiel de l'articulation du genou, insert tibial postéro-
stabilisé, implant de référence, utilisation clinique suffisante et sans danger, insert tibial, prothèse
totale de l'articulation du genou et remplacement total de l'articulation du genou, polyéthylène à
très haute masse moléculaire et PE-UHMW, prothèse unicompartimentale de l'articulation du genou
et PUC, et cas le plus défavorable;
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ISO 21536:2023(F)
— les attributs de conception à prendre en compte ont été précisés à l'Article 5. Les exigences portant
sur l'épaisseur des différents composants d'articulation de genou en plastique, en métal et en
céramique ont été élargies;
— plusieurs nouvelles exigences générales ont été ajoutées en 7.2.1, qui spécifient:
a) les circonstances dans lesquelles un essai peut être omis;
b) l'essai du cas le plus défavorable;
c) les processus à suivre lorsqu'aucune exigence de performance n'a été spécifiée; et
d) les processus à suivre lorsqu'une exigence de performance a été spécifiée, mais n'a pas été
satisfaite;
— le nombre d'évaluations précliniques (essais au banc) à réaliser a été considérablement augmenté
en 7.2.2. Pour certains de ces essais, une exigence de performance a été spécifiée. Pour certains de
ces essais, aucune exigence de performance n'a été spécifiée et, dans ces cas, une nouvelle exigence
a été ajoutée, à savoir une exigence pour démontrer que la performance de l'implant évalué est égale
ou supérieure à celle d'un implant de référence. En l'absence d'implant de référence, une séquence
d'options alternatives a été spécifiée. Ces options alternatives sont également applicables dans le
cas où une exigence de performance existe, mais n'est pas satisfaite par l'implant soumis à essai;
— un nouveau paragraphe relatif à l'investigation clinique a été ajouté en 7.3, comprenant plusieurs
exigences qui spécifient les circonstances dans lesquelles une investigation clinique peut être
requise;
— un nouveau paragraphe relatif à la surveillance après mise sur le marché a été ajouté en 7.4, faisant
référence aux exigences de l'ISO 21534:2007, 7.4;
— plusieurs nouvelles exigences de marquage ont été spécifiées en 11.4;
— une note a été ajoutée en 11.6, indiquant que dans certaines juridictions, il est possible de fournir les
instructions d'utilisation sous forme électronique plutôt que sur papier.
Il convient que l'utilisateur adresse tout retour d'information ou toute question concernant le présent
document à l'organisme national de normalisation de son pays. Une liste exhaustive desdits organismes
se trouve à l'adresse www.iso.org/fr/members.html.
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ISO 21536:2023(F)
Introduction
Les normes relatives aux implants chirurgicaux non actifs sont réparties en trois niveaux, le niveau 1
étant le plus élevé:
— niveau 1: exigences générales relatives aux implants chirurgicaux non actifs et aux instruments
utilisés en association avec les implants;
— niveau 2: exigences particulières relatives aux familles d'implants chirurgicaux non actifs;
— niveau 3: exigences spécifiques à certains types d'implants chirurgicaux non actifs.
Le présent document est de niveau 3 et énonce des exigences spécifiquement applicables aux prothèses
de l'articulation du genou.
L'ISO 14630, relevant du niveau 1, contient des exigences qui s'appliquent à tous les implants
chirurgicaux non actifs. Elle indique également que certaines exigences supplémentaires sont données
dans les normes de niveaux 2 et 3.
Les normes de niveau 2 s'appliquent à des séries ou à des familles plus restreintes d'implants, tels que
ceux destinés à être utilisés en ostéosynthèse, en chirurgie cardiovasculaire ou en arthroplastie. Pour
les implants de remplacement des articulations, la norme de niveau 2 est l'ISO 21534.
Pour couvrir toutes les exigences, il est préférable de consulter en premier lieu la norme du niveau le
plus bas existant.
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NORME INTERNATIONALE ISO 21536:2023(F)
Implants chirurgicaux non actifs — Implants de
remplacement d'articulation — Exigences spécifiques
relatives aux implants de remplacement de l'articulation
du genou
1 Domaine d'application
Le présent document spécifie les exigences relatives aux prothèses de l'articulation du genou. En
matière de sécurité, le présent document fournit des exigences relatives aux performances prévues, à la
conception, aux matériaux, à l'évaluation de la conception, à la fabrication, à la stérilisation, à l'emballage
et aux informations devant être fournies par le fabricant ainsi que des méthodes d'essai.
Le présent document s'applique à la fois aux implants de remplacement total et partiel de l'articulation
du genou. Il s'applique à ces remplacements avec et sans remplacement de l'articulation fémoro-
patellaire. Il s'applique aux composants fabriqués en matériaux métalliques et non métalliques.
Le présent document s'applique à une grande variété d'implants, mais certaines considérations,
non spécifiquement couvertes dans le présent document, peuvent être applicables à certains types
spécifiques d'implants de remplacement de l'articulation du genou. Voir 7.2.1.2 pour plus de détails.
Les exigences spécifiées dans le présent document n'ont pas pour but d'exiger une nouvelle conception
ou de nouveaux essais sur des implants qui ont été légalement mis sur le marché et pour lesquels il
existe un historique d'utilisation clinique suffisante et sans danger. Pour ces implants, la conformité au
présent document peut être démontrée en fournissant la preuve d'une utilisation clinique suffisante et
sans danger de l'implant.
2 Références normatives
Les documents suivants sont cités dans le texte de sorte qu’ils constituent, pour tout ou partie de leur
contenu, des exigences du présent document. Pour les références datées, seule l’édition citée s’applique.
Pour les références non datées, la dernière édition du document de référence s'applique (y compris les
éventuels amendements).
ISO 5834-1, Implants chirurgicaux — Polyéthylène à très haute masse moléculaire — Partie 1: Produits
sous forme de poudre
ISO 7207-1:2007, Implants chirurgicaux — Éléments de prothèses partielle et totale de l'articulation du
genou — Partie 1: Classification, définitions et désignation des dimensions
ISO 7207-2, Implants chirurgicaux — Éléments de prothèses partielle et totale de l'articulation du genou —
Partie 2: Surfaces articulaires constituées de matériaux métalliques, céramiques et plastiques
ISO 10993-1, Évaluation biologique des dispositifs médicaux — Partie 1: Évaluation et essais au sein d'un
processus de gestion du risque
ISO 14243-1, Implants chirurgicaux — Usure des prothèses totales de l'articulation du genou — Partie
1: Paramètres de charge et de déplacement pour machines d'essai d'usure avec contrôle de la charge et
conditions environnementales correspondantes d'essai
ISO 14243-2, Implants chirurgicaux — Usure des prothèses totales de l'articulation du genou — Partie 2:
Méthodes de mesure
1
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ISO 21536:2023(F)
ISO 14243-3, Implants chirurgicaux — Usure des prothèses totales de l'articulation du genou — Partie 3:
Paramètres de charge et de déplacement pour machines d'essai d'usure avec contrôle de déplacement et
conditions environnementales correspondantes d'essai
ISO 14243-5, Implants chirurgicaux — Usure des prothèses totales du genou — Partie 5: Performance de
durabilité de l'articulation fémoro-patellaire
ISO 14630, Implants chirurgicaux non actifs — Exigences générales
ISO 14879-1, Implants chirurgicaux — Prothèses totales de l'articulation du genou — Partie 1:
Détermination des propriétés d'endurance des embases tibiales
ISO 21534:2007, Implants chirurgicaux non actifs — Implants de remplacement d'articulation — Exigences
particulières
ASTM F648, Standard Specification for Ultra-High-Molecular-Weight Polyethylene Powder and Fabricated
Form for Surgical Implants
ASTM F1223, Standard Test Method for Determination of Total Knee Replacement Constraint
ASTM F2722, Standard Practice for Evaluating Mobile Bearing Knee Tibial Baseplate Rotational Stops
ASTM F2723, Standard Test Method for Evaluating Mobile Bearing Knee Tibial Baseplate/Bearing
Resistance to Dynamic Disassociation
ASTM F2724, Standard Test Method for Evaluating Mobile Bearing Knee Dislocation
ASTM F2777, Standard Test Method for Evaluating Knee Bearing (Tibial Insert) Endurance and Deformation
Under High Flexion
ASTM F3210, Standard Test Method for Fatigue Testing of Total Knee Femoral Components under Closing
Conditions
3 Termes et définitions
Pour les besoins du présent document, les termes et définitions de l'ISO 7207-1, l'ISO 14630 et
l'ISO 21534 ainsi que les suivants s'appliquent.
L'ISO et l'IEC tiennent à jour des bases de données terminologiques destinées à être utilisées en
normalisation, consultables aux adresses suivantes:
— ISO Online browsing platform: disponible à l'adresse https:// www .iso .org/ obp
— IEC Electropedia: disponible à l'adresse https:// www .electropedia .org/
3.1
composant fémoral
élément d'une prothèse totale de l'articulation du genou (3.14), d'une prothèse fémoro-patellaire de
l'articulation du genou ou d'une prothèse unicompartimentale de l'articulation du genou (3.16) destiné à
être fixé sur le fémur pour remplacer une ou plusieurs des surfaces articulaires
3.2
flexion maximale revendiquée
plus grand degré de flexion que la prothèse totale de l'articulation du genou (3.14) ou la prothèse
unicompartimentale de l'articulation du genou (3.16) peut atteindre selon les déclarations du fabricant à
partir des exigences définies au 7.2.2.11
Note 1 à l'article: Un degré de flexion supérieur à la flexion maximale revendiquée peut exister sur la base d'une
conception assistée par ordinateur (CAO) ou de considérations relatives à la forme de l'implant.
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ISO 21536:2023(F)
3.3
insert mobile
élément de la prothèse articulaire mobile de l'articulation du genou (3.4), totale ou unicompartimentale,
qui s'articule à la fois avec le composant fémoral (3.1) et le plateau tibial (3.13)
Note 1 à l'article: L'insert mobile peut être monobloc ou constitué de plusieurs composants, et destiné dans les
deux cas à être assemblé par l'utilisateur dans la prothèse articulaire mobile de l'articulation du genou (3.4).
Note 2 à l'article: L'insert mobile est généralement un sous-composant de l'élément tibial (3.11), soutenu par le
plateau tibial (3.13).
Note 3 à l'article: L'insert mobile peut aussi être appelé «composant méniscal».
[SOURCE: ISO 7207-1:2007, 3.2.10, modifiée — La Note 1 à l'article a été remplacée et les Notes 2 et 3 à
l'article ont été ajoutées.]
3.4
prothèse articulaire mobile de l'articulation du genou
prothèse totale de l'articulation du genou (3.14) ou prothèse unicompartimentale de l'articulation du genou
(3.16) permettant un mouvement relatif entre l’insert mobile (3.3) et le composant fémoral (3.1) d'une
part et l’insert mobile (3.3) et le plateau tibial (3.13) d'autre part
[SOURCE: ISO 7207-1:2007, 3.1.6, modifiée — «de l'articulation du genou» a été ajouté après «totale»
dans la définition et la Note 1 à l'article a été supprimée.]
3.5
prothèse partielle de l'articulation du genou
remplacement partiel de l'articulation du genou
prothèse unicompartimentale de l'articulation du genou (3.16) ou ensemble d'éléments utilisé pour
remplacer les surfaces articulaires fémorale et tibiale dans le compartiment médial d'une articulation
du genou, ainsi que les surfaces articulaires de la rotule et du fémur dans le compartiment fémoro-
patellaire
Note 1 à l'article: Les implants destinés à réparer des défauts focaux du cartilage ou à être utilisés pour une
procédure chirurgicale, telle que la mosaïcplastie, ne constituent pas des prothèses partielles de l'articulation du
genou dans le cadre du présent document.
3.6
élément rotulien
élément d'une prothèse totale de l'articulation du genou (3.14), d'une prothèse partielle de l'articulation
du genou (3.5) ou d'une prothèse fémoro-patellaire de l'articulation du genou, utilisé pour remplacer la
surface articulaire de la rotule
Note 1 à l'article: Les éléments rotuliens peuvent être monoblocs ou modulaires.
3.7
composant de soutien rotulien
sous-élément de l'élément rotulien (3.6) modulaire de la prothèse totale d'une articulation du genou (3.14),
d'une prothèse partielle de l’articulation du genou (3.5) ou d'une prothèse de l’articulation rotulienne-
fémorale du genou, utilisé pour soutenir et fixer l'insert rotulien
[SOURCE: ISO 7207-1:2007, 3.2.14, modifié — « d'une prothèse partielle de l’articulation du genou (3.5)
ou d'une prothèse de l’articulation rotulienne-fémorale du genou » a été ajoutée à la définition.]
3.8
insert tibial postéro-stabilisé
insert tibial (3.12) avec une protrusion arrière ou un autre mécanisme qui s'interface avec le composant
fémoral (3.1) pour limiter la translation antérieure du composant fémoral lorsque le genou est en flexion
Note 1 à l'article: La partie du composant fémoral en interface avec la protrusion de l'insert tibial est parfois
appelée la «came».
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ISO 21536:2023(F)
3.9
implant de référence
implant ayant obtenu une autorisation de mise sur le marché qui, lorsqu'il est comparé à l'implant
évalué, satisfait aux deux conditions ci-dessous:
a) il présente la même utilisation prévue, des matériaux similaires et une conception similaire
concernant les critères dimensionnels ou de performance spécifiques évalués en vue de répondre
aux mêmes exigences cliniques et techniques; et
b) il existe des preuves d'utilisation clinique réussie en nombre suffisant, pendant une période de
temps suffisante et, au minimum, sans preuve connue ou raisonnablement connue de rappels liés
à la conception ou aux performances concernant les critères dimensionnels ou de performance
spécifiques évalués.
Note 1 à l'article: Le terme «référence» n'implique en aucun cas que l'implant évalué et l'implant de référence
sont «équivalents» ou que l'implant de référence est un implant «prédicat». En effet, pour certains organismes
réglementaires, les termes «équivalent» et «prédicat» ont une signification qui va au-delà de celle prévue par le
terme «référence» tel qu'il est utilisé dans le présent document.
Note 2 à l'article: L'implant de référence est l'implant de comparaison pour le ou les paramètres dimensionnels
ou de performance évalués. D'autres caractéristiques de l'implant de référence doivent être prises en compte
pour que la comparaison soit appropriée, étant donné qu'il peut y avoir des effets croisés dans certains cas.
Idéalement, pour la majorité des paramètres dimensionnels et de performance, il convient d'utiliser un seul
implant de référence à comparer à l'implant évalué. Cependant, on peut utiliser plusieurs implants de référence
dans le cadre de la comparaison, avec une justification scientifique et clinique adéquate.
Note 3 à l'article: Certains organismes réglementaires exigent qu'un implant de référence ait obtenu une
autorisation de mise sur le marché dans leur propre pays ou juridiction. Cet élément peut être pris en compte lors
de la sélection d'un implant de référence aux fins du présent document.
Note 4 à l'article: Il n'existe pas d'interprétation unanime de ce qui constitue un «nombre suffisant» ou une
«période de temps suffisante» dans la définition ci-dessus. En règle générale, la détermination de ce qui constitue
un «nombre suffisant» et une «période de temps suffisante» est démontrée en utilisant des méthodes statistiques
et un jugement clinique dans l'évaluation des performances de l'implant.
Note 5 à l'article: La justification d'un «matériau similaire» peut inclure des informations selon lesquelles, bien
que les matériaux ne soient pas les mêmes, il peut être démontré que le ou les matériaux utilisés pour l'implant
évalué présentent des performances similaires en ce qui concerne l'essai ou sa préoccupation clinique sous-
jacente.
Note 6 à l'article: Les moyens de fixation, la modularité, les contraintes, les dimensions clés et la forme, le
traitement, la topographie de surface, le traitement de surface, etc., sont des exemples de caractéristiques de
conception pouvant être pris en compte pour évaluer si un implant possède une «conception similaire» à l'implant
évalué. La justification d'une «conception similaire» peut donc inclure des informations selon lesquelles, bien que
les conceptions ne soient pas les mêmes, il peut être démontré que la conception de l'implant évalué présente des
performances similaires en ce qui concerne l'essai ou sa préoccupation clinique sous-jacente.
Note 7 à l'article: Il incombe au fabricant d'identifier le ou les implants de référence conformément aux exigences
réglementaires des juridictions dans lesquelles l'implant évalué doit être mis sur le marché.
3.10
utilisation clinique suffisante et sans danger
utilisation cliniq
...
ISO/FDIS 21536
ISO/TC 150/SC 4
Secretariat: BSI
Date: 2023-02-22
Non-active surgical implants — Joint replacement implants —
Specific requirements for knee-joint replacement implants
Implants chirurgicaux non actifs — Implants de remplacement d'articulation — Exigences spécifiques
relatives aux implants de remplacement de l'articulation du genou
FDIS stage
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ISO/DISFDIS 21536:20212023(E)
© ISO 2023
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this
publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical,
including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can
be requested from either ISO at the address below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: + 41 22 749 01 11
E-mail: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2023 – All rights reserved
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ISO/FDIS 21536:20212023(E)
Contents Page
Foreword . v
Introduction .vi i
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Intended performance . 6
5 Design attributes . 7
5.1 General . 7
5.2 Tolerances and dimensions . 8
5.2.1 Tolerances and dimensions of taper connections . 8
5.2.2 Surface finish of non-articulating regions of knee joint components . 8
5.2.3 Surface finish of articulating surfaces of knee joint components . 8
5.3 Thickness of knee joint components . 8
5.3.1 General . 8
5.3.2 Thickness of UHMWPE in tibial inserts, monobloc tibial components, mobile-bearing
components, patella inserts and monobloc patellar components . 9
5.3.3 Thickness of metal and ceramic in femoral components, tibial trays and patellar trays . 9
6 Materials . 10
7 Design evaluation . 10
7.1 General . 10
7.2 Pre-clinical evaluation . 10
7.2.1 General . 10
7.2.2 Test methods and performance requirements . 12
7.3 Clinical investigation . 19
7.4 Post market surveillance . 19
8 Manufacture . 19
9 Sterilization . 19
10 Packaging . 19
11 Information to be supplied by the manufacturer . 19
11.1 General . 19
11.2 Product type and dimensions . 20
11.3 Constructional and functional compatibility of components . 20
11.4 Marking . 20
11.5 Information for the patient . 20
11.6 Electronic instructions for use . 20
Annex A (informative) Evaluation of the range of relative angular motion of components of fully
constrained total knee joint replacement implants . 21
Annex ZA (informative) Relationship between this European standard and the General Safety and
Performance Requirements of Regulation (EU) 2017/745 aimed to be covered . 22
© ISO 2023 – All rights reserved iii
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ISO/DISFDIS 21536:20212023(E)
Bibliography . 26
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ISO/FDIS 21536:20212023(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO
collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any
patent rights identified during the development of the document will be in the Introduction and/or on
the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the World
Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 150, Implants for surgery, Subcommittee
SC 4, Bone and joint replacements, in collaboration with the European Committee for Standardization
(CEN) Technical Committee CEN/TC 285, Non-active surgical implants, in accordance with the Agreement
on technical cooperation between ISO and CEN (Vienna Agreement).
This third edition cancels and replaces the second edition (ISO 21536:2007), which has been technically
revised. It also incorporates the Amendment ISO 21536:2007/Amd 1:2014.
This third edition is a major revision with many added requirements. The main changes are as follows:
— 1 Scope
— The scope ishas been expanded to specify more precisely the knee joint replacement types which are
the subject of this document. Also, the scope now clarifies the requirements for implants which have
been legally marketed and for which there is a history of sufficient and safe clinical use.
— 2 Normative references
— The number of normative references has been expanded, including the addition of several ASTM
standards.
— 3 Terms and definitions
— Several new definitions arehave been added, including: a) maximum claimed flexion, b) mobile-
bearing component, c) mobile-bearing knee joint prosthesis, d) partial knee joint prosthesis and
partial knee joint replacement, e) posterior stabilized tibial insert, f) reference implant, g) sufficient
and safe clinical use, h) tibial insert, i) total knee joint prosthesis and total knee joint replacement,
© ISO 2023 – All rights reserved v
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ISO/DISFDIS 21536:20212023(E)
j)ultra-high molecular weight polyethylene and UHMWPE, uni-compartmental knee joint
replacement and UKR, k) UHMWPE and l) worst case.
— 5 Design attributes
The design attributes to be taken into account arehave been specified in Clause 5.
— . The requirements for the thickness of various knee joint components made from plastic, metal and
ceramic have been expanded.
— 7.2.1 General
— Several new general requirements arehave been added in 7.2.1. These new requirements a), which
specify
a) the circumstances when a test can be omitted, b) specify that
b) the testing of the worst case shall be tested and c) specify ,
a)c) the processes to be followed when no performance requirement has been specified, and
b)d) d) specify the processes to be followed when a performance requirement has been
specified but has not been met.
— 7.2.2 Pre-clinical evaluation
— The number of pre-clinical evaluations (bench tests) to be performed ishas been greatly increased in
7.2.2. For some of the tests, a performance requirement ishas been specified. For some of the tests
no performance requirement ishas been specified and, in these cases, a new requirement has been
added, namely the requirement to demonstrate that the performance of the implant under evaluation
is the same or better than that of a reference implant. If no reference implant exists, a sequence of
alternative options ishas been specified. These alternative options are also available in the case where
there is a performance requirement, which is not met by the implant being tested.
— 7.3 Clinical investigation
— A new clinical investigation subclause ishas been added in 7.3, with several requirements which
specify the circumstances in which a clinical investigation can be required.
— 7.4 Post market surveillance
A new post-market surveillance subclause ishas been added in 7.4,, which references the
requirements in ISO 21534:2007, 7.4.
— — 11.4 Marking.
— Several new marking requirements arehave been specified in 11.4.
— 11.6 Electronic instructions for use
— A note ishas been added in 11.6 which states that in some jurisdictions there is the option to provide
the instructions for use in electronic instead of paper format.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
Field Code Changed
vi © ISO 2023 – All rights reserved
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ISO/FDIS 21536:20212023(E)
Introduction
There are three levels of standards dealing with non-active surgical implants. These are as follows, with
level 1 being the highest:
— — level 1: general requirements for non-active surgical implants and instrumentation used in
association with implants;
— — level 2: particular requirements for families of non-active surgical implants;
— — level 3: specific requirements for types of non-active surgical implant.
This document is a level 3 standard and contains requirements applying specifically to knee joint
replacements.
The level 1 standard, ISO 14630, contains requirements that apply to all non-active surgical implants. It
also indicates that there are additional requirements in the level 2 and level 3 standards.
The level 2 standards apply to more restricted sets or families of implants such as those designed for use
in osteosynthesis, cardiovascular surgery or joint replacement. For joint replacement implants, the level
2 standard is ISO 21534.
To address all requirements, it is recommended that a standard of the lowest available level be consulted
first.
© ISO 2023 – All rights reserved vii
© ISO 2021 – All rights reserved
vii
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ISO/FDIS 21536:2023(E)
Non-active surgical implants — Joint replacement implants —
Specific requirements for knee-joint replacement implants
1 Scope
This document specifies requirements for knee-joint replacement implants. Regarding safety, this
document specifies requirements for intended performance, design attributes, materials, design
evaluation, manufacture, sterilization, packaging, information supplied by the manufacturer and methods
of test.
This document applies to both total and partial knee joint replacement implants. It applies to these
replacements both with and without the replacement of the patella-femoral joint. It applies to
components made of metallic and non-metallic materials.
This document applies to a wide variety of knee replacement implants, but for some specific knee
replacement implant types, some considerations, not specifically covered in this document, can be
applicable. Further details are given in 7.2.1.27.2.1.2.
The requirements which are specified in this document are not intended to require the re-design or re-
testing of implants which have been legally marketed and for which there is a history of sufficient and
safe clinical use. For such implants, compliance with this document can be demonstrated by providing
evidence of the implant’s sufficient and safe clinical use.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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.
ISO 5834-1, Implants for surgery — Ultra-high-molecular-weight polyethylene — Part 1: Powder form
ISO 7207--1:2007, Implants for surgery — Components for partial and total knee joint prostheses — Part
1: Classification, definitions and designation of dimensions
ISO 7207--2, Implants for surgery — Components for partial and total knee joint prostheses — Part 2:
Articulating surfaces made of metal, ceramic and plastics materials
ISO 10993-1, Biological evaluation of medical devices –— Part 1: Evaluation and testing within a risk
management process
ISO 14243--1, Implants for surgery — Wear of total knee-joint prostheses — Part 1: Loading and
displacement parameters for wear-testing machines with load control and corresponding environmental
conditions for test
ISO 14243--2, Implants for surgery — Wear of total knee-joint prostheses — Part 2: Methods of
measurement
ISO 14243--3, Implants for surgery — Wear of total knee-joint prostheses — Part 3: Loading and
displacement parameters for wear-testing machines with displacement control and corresponding
environmental conditions for test
ISO 14243--5, Implants for surgery — Wear of total knee prostheses — Part 5: Durability performance of
the patellofemoral joint
ISO 14630, Non-active surgical implants — General requirements
ISO 14879--1, Implants for surgery — Total knee-joint prostheses — Part 1: Determination of endurance
properties of knee tibial trays
ISO 21534:2007, Non-active surgical implants — Joint replacement implants — Particular requirements
© ISO 2023 – All rights reserved 1
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ISO/FDIS 21536:2023(E)
ASTM F648, Standard Specification for Ultra-High-Molecular-Weight Polyethylene Powder and Fabricated
Form for Surgical Implants
ASTM F1223, Standard Test Method for Determination of Total Knee Replacement Constraint
ASTM F2722, Standard Practice for Evaluating Mobile Bearing Knee Tibial Baseplate Rotational Stops
ASTM F2723, Standard Test Method for Evaluating Mobile Bearing Knee Tibial Baseplate/Bearing
Resistance to Dynamic Disassociation
ASTM F2724, Standard Test Method for Evaluating Mobile Bearing Knee Dislocation
ASTM F2777, Standard Test Method for Evaluating Knee Bearing (Tibial Insert) Endurance and
Deformation Under High Flexion
ASTM F3210, Standard Test Method for Fatigue Testing of Total Knee Femoral Components under Closing
Conditions
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 14630, ISO 21534 and
ISO 7207-1 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— — ISO Online browsing platform: available fromat https://www.iso.org/obp
— — IEC Electropedia: available at https://www.electropedia.org/
3.1
femoral component
component of a total knee joint prosthesis (3.14(3.14),), patella-femoral knee joint prosthesis, or uni-
compartmental knee joint prosthesis (3.16(3.16)) intended to be secured to the femur to replace its
articulating surface(s)
[SOURCE: ISO 7207-1:2007, 3.2.3, modified – text has been added and NOTE has been deleted]
3.2
maximum claimed flexion
highest amount of flexion the total knee joint prosthesis (3.14(3.14)) or uni-compartmental knee joint
prosthesis (3.16(3.16)) can achieve as claimed by the manufacturer based on the requirements defined in
7.2.2.117.2.2.11
Note 1 to entry: A higher amount of flexion than the maximum claimed flexion can exist based on computer aided
design (CAD) or implant shape considerations.
3.3
mobile-bearing component
component of a total or uni-compartmental mobile-bearing knee joint prosthesis (3.4(3.4)) which
articulates with both the femoral component (3.1(3.1)) and the tibial tray (3.13(3.13))
[SOURCE: ISO 7207-1:2007, 3.2.10, modified – NOTE has been deleted]
Note 1 to entry: The mobile-bearing component can be manufactured as one component or a set of components, in
both cases intended to be assembled in the mobile-bearing knee joint prosthesis (3.4(3.4)) by the user.
Note 2 to entry: The mobile-bearing component is usually a sub-component of the tibial component (3.11(3.11),),
supported by the tibial tray (3.13(3.13).).
Note 3 to entry: The mobile-bearing component can also be referred to as the meniscal component.
2
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ISO/FDIS 21536:2023(E)
[SOURCE: ISO 7207-1:2007, 3.2.10, modified — Note 1 to entry has been replaced and Notes 2 and 3 to
entry have been added.]
3.4
mobile-bearing knee joint prosthesis
total knee joint prosthesis (3.14(3.14)) or uni-compartmental knee joint prosthesis (3.16(3.16)) which
allows relative motion between the mobile-bearing component (3.3(3.3)) and both the femoral component
(3.1(3.1)) and the tibial tray (3.13(3.13))
[SOURCE: ISO 7207-1:2007, 3.1.6, modified – text— "knee joint prosthesis" has been added after "total"
in the definition and NOTENote 1 to entry has been deleted].]
3.5
partial knee joint prosthesis
partial knee joint replacement
either a uni-compartmental knee joint prosthesis (3.16(3.16)) or a set of components used to replace the
femoral and tibial articulating surfaces in the medial compartment of a knee joint and also the patellar
and femoral articulating surfaces in the patella-femoral compartment
Note 1 to entry: Implants which are intended to repair a cartilage focal defect(s) or to be used for a surgical
procedure like mosaicplasty are not partial knee joint prostheses for the purposes of this document.
3.6
patellar component
component of a total knee joint prosthesis (3.14(3.14)) or partial knee joint prosthesis (3.5(3.5)) or patella-
femoral knee joint prosthesis which is used to replace the articulating surface of the patella
Note 1 to entry: Patellar components can be monobloc or modular.
[SOURCE: ISO 7207-1:2007, 3.2.13, modified – text has been added and NOTE has been modified to delete reference
to Figure]
3.7
patellar tray
sub-component of a modular patellar component (3.6(3.6)) of a total knee joint prosthesis (3.14(3.14))
used to support and secure the patellar insert
[SOURCE: ISO 7207-1:2007, 3.2.14]
3.8
posterior stabilized tibial insert
tibial insert (3.12(3.12)) with a centre post protruding superiorly or some other mechanism which
interfaces with the femoral component (3.1(3.1)) to restrict anterior translation of the femoral component
(3.1(3.1)) when the knee is in flexion
Note 1 to entry: The portion of the femoral component (3.1(3.1)) interfacing with the tibial insert (3.12) centre post
is sometimes referred to as the “cam”.
3.9
reference implant
legally-marketed implant which, when compared to the implant under evaluation, satisfies both of the
following conditions:
a) a) it has the same intended use, similar materials and a similar design with regard to the specific
dimensional or performance criteria under evaluation to address the same clinical and technical
requirements, and
© ISO 2023 – All rights reserved 3
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ISO/FDIS 21536:2023(E)
b) b) there is evidence of successful clinical use in sufficient numbers; for a sufficient period of time;
and, at a minimum, without known or reasonably-known evidence of design or performance-related
recalls with regard to the specific dimensional or performance criteria under evaluation
Note 1 to entry: The term “reference” is not intended to imply that the implant under evaluation and the reference
implant are “equivalent” or that the reference implant is a “predicate” implant. This is because for some regulatory
authorities, the terms “equivalent” and “predicate” have a meaning, which is beyond that intended by the term
“reference” as used in this document.
Note 2 to entry: A reference implant is the comparison implant for dimensional or performance parameter(s) under
evaluation. Other characteristics of the reference implant shall be considered in order for the comparison to be
suitable, as in some situations there can be cross-effects. Ideally, for the majority of dimensional and performance
parameters, a single reference implant should be used for comparison to the implant under evaluation. However,
more than one reference implant may be used for comparison purposes, with adequate scientific and clinical
justification.
Note 3 to entry: Some regulatory authorities require that a reference implant is one that is legally marketed in their
own country or jurisdiction. This fact can be taken into account when selecting a reference implant for the purposes
of this document.
Note 4 to entry: There is no agreed upon interpretation for what constitutes “sufficient numbers” or a “sufficient
period of time” in the above definition. Typically, a determination of what constitutes “sufficient numbers” and a
“sufficient period of time” is demonstrated by using statistical methods and clinical judgement in the evaluation of
implant performance.
Note 5 to entry: A justification for a “similar material” may include information that although the materials are not
the same, the material(s) used for the implant under evaluation can be shown to perform similarly with regard to
the test or its underlying clinical concern.
Note 6 to entry: Examples of design features that can be taken into consideration when evaluating whether an
implant has a ‘similar design’ to the implant under evaluation include means of fixation, modularity, constraint, key
dimensions and shape, processing, surface topography, surface treatment, etc. A justification for a “similar design”
therefore may include information that although the designs are not the same, the design of the implant under
evaluation can be shown to perform similarly with regard to the test or its underlying clinical concern.
Note 7 to entry: The manufacturer is responsible for identifying the reference implant(s) in accordance with the
regulatory requirements in the jurisdictions where the implant under evaluation is to be marketed.
3.10
sufficient and safe clinical use
clinical use of a legally-marketed implant in sufficient numbers, for a sufficient period of time and, at a
minimum, without known or reasonably-known evidence of design or performance-related recalls
Note 1 to entry: There is no agreed interpretation for what constitutes “sufficient numbers” or “sufficient period of
time” in the above definition. Typically, these are demonstrated by using statistical methods and clinical judgement
in the evaluation of implant performance.
Note 2 to entry: Some regulatory authorities require that a legally-marketed implant is one which is legally
marketed in their country or jurisdiction.
Note 3 to entry: For a legally-marketed system of knee replacement implants, there can be evidence to demonstrate
sufficient and safe clinical use for some parts of the system (e.g. some components and some sizes) but not for
others. For those parts of the system for which there is sufficient evidence, the requirements of this document
relating to design and testing shall not apply. For those parts of the system for which there is not sufficient evidence
to demonstrate sufficient and safe clinical use the requirements of this document relating to design and testing shall
apply.
Note 4 to entry: The manufacturer is responsible for identifying the implant with sufficient and safe clinical use in
accordance with the regulatory requirements in the jurisdictions where the implant is to be marketed.
4
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ISO/FDIS 21536:2023(E)
3.11
tibial component
component of a total knee joint prosthesis (3.14(3.14)) or uni-compartmental knee joint prosthesis
(3.16(3.16)) intended to be secured to the tibia to replace its articulating surface(s)
Note 1 to entry: Tibial components can be monobloc or modular. When modular the tibial component usually
consists either of a tibial insert (3.12(3.12)) or a mobile-bearing component (3.3(3.3);); and a tibial tray (3.13(3.13).).
[SOURCE: ISO 7207-1:2007, 3.2.5, modified - text— "knee joint prosthesis" has been added and NOTE has
been modified byafter "total" in the addition of thedefinition and a second sentence above]has been
added to Note 1 to entry.]
3.12
tibial insert
sub-component of a modular tibial component (3.11(3.11)) of a total knee joint prosthesis (3.14(3.14)) or
uni-compartmental knee joint prosthesis (3.16(3.16)) which is attached to the tibial tray (3.13(3.13)) and
which articulates with the femoral component (3.
...
FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 21536
ISO/TC 150/SC 4
Non-active surgical implants —
Secretariat: BSI
Joint replacement implants —
Voting begins on:
2023-03-08 Specific requirements for knee-joint
replacement implants
Voting terminates on:
2023-05-03
Implants chirurgicaux non actifs — Implants de remplacement
d'articulation — Exigences spécifiques relatives aux implants de
remplacement de l'articulation du genou
ISO/CEN PARALLEL PROCESSING
RECIPIENTS OF THIS DRAFT ARE INVITED TO
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/FDIS 21536:2023(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN-
DARDS TO WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS. © ISO 2023
---------------------- Page: 1 ----------------------
ISO/FDIS 21536:2023(E)
FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 21536
ISO/TC 150/SC 4
Non-active surgical implants —
Secretariat: BSI
Joint replacement implants —
Voting begins on:
Specific requirements for knee-joint
replacement implants
Voting terminates on:
Implants chirurgicaux non actifs — Implants de remplacement
d'articulation — Exigences spécifiques relatives aux implants de
remplacement de l'articulation du genou
COPYRIGHT PROTECTED DOCUMENT
© ISO 2023
ISO/CEN PARALLEL PROCESSING
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
RECIPIENTS OF THIS DRAFT ARE INVITED TO
ISO copyright office
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
CP 401 • Ch. de Blandonnet 8
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
CH-1214 Vernier, Geneva
DOCUMENTATION.
Phone: +41 22 749 01 11
IN ADDITION TO THEIR EVALUATION AS
Reference number
Email: copyright@iso.org
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO
ISO/FDIS 21536:2023(E)
Website: www.iso.org
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
Published in Switzerland
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN
DARDS TO WHICH REFERENCE MAY BE MADE IN
ii
© ISO 2023 – All rights reserved
NATIONAL REGULATIONS. © ISO 2023
---------------------- Page: 2 ----------------------
ISO/FDIS 21536:2023(E)
Contents Page
Foreword .iv
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Intended performance .6
5 Design attributes .6
5.1 General . 6
5.2 Tolerances and dimensions . 7
5.2.1 Tolerances and dimensions of taper connections . 7
5.2.2 Surface finish of non-articulating regions of knee joint components . 8
5.2.3 Surface finish of articulating surfaces of knee joint components . 8
5.3 Thickness of knee joint components . 8
5.3.1 General . 8
5.3.2 Thickness of UHMWPE in tibial inserts, monobloc tibial components,
mobilebearing components, patella inserts and monobloc patellar
components . 8
5.3.3 Thickness of metal and ceramic in femoral components, tibial trays and
patellar trays . . . 9
6 Materials .10
7 Design evaluation .10
7.1 General . 10
7.2 Preclinical evaluation . . 10
7.2.1 General . 10
7.2.2 Test methods and performance requirements .12
7.3 Clinical investigation . 18
7.4 Post market surveillance . 19
8 Manufacture .19
9 Sterilization .19
10 Packaging.19
11 Information to be supplied by the manufacturer .19
11.1 General . 19
11.2 Product type and dimensions . 19
11.3 Constructional and functional compatibility of components . 20
11.4 Marking . 20
11.5 Information for the patient . 20
11.6 Electronic instructions for use . 20
Annex A (informative) Evaluation of the range of relative angular motion of components of
fully constrained total knee joint replacement implants .21
Annex ZA (informative) Relationship between this European standard and the General
Safety and Performance Requirements of Regulation (EU) 2017/745 aimed to be
covered .22
Bibliography .25
iii
© ISO 2023 – All rights reserved
---------------------- Page: 3 ----------------------
ISO/FDIS 21536:2023(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 150, Implants for surgery, Subcommittee
SC 4, Bone and joint replacements, in collaboration with the European Committee for Standardization
(CEN) Technical Committee CEN/TC 285, Non-active surgical implants, in accordance with the Agreement
on technical cooperation between ISO and CEN (Vienna Agreement).
This third edition cancels and replaces the second edition (ISO 21536:2007), which has been technically
revised. It also incorporates the Amendment ISO 21536:2007/Amd 1:2014.
The main changes are as follows:
— The scope has been expanded to specify more precisely the knee joint replacement types which are
the subject of this document. Also, the scope now clarifies the requirements for implants which have
been legally marketed and for which there is a history of sufficient and safe clinical use.
— The number of normative references has been expanded, including the addition of several ASTM
standards.
— Several new definitions have been added, including: maximum claimed flexion, mobile-bearing
component, mobile-bearing knee joint prosthesis, partial knee joint prosthesis and partial knee
joint replacement, posterior stabilized tibial insert, reference implant, sufficient and safe clinical
use, tibial insert, total knee joint prosthesis and total knee joint replacement, ultra-high molecular
weight polyethylene and UHMWPE, uni-compartmental knee joint replacement and UKR, and worst
case.
— The design attributes to be taken into account have been specified in Clause 5. The requirements
for the thickness of various knee joint components made from plastic, metal and ceramic have been
expanded.
— Several new general requirements have been added in 7.2.1, which specify
a) the circumstances when a test can be omitted,
b) the testing of the worst case,
iv
© ISO 2023 – All rights reserved
---------------------- Page: 4 ----------------------
ISO/FDIS 21536:2023(E)
c) the processes to be followed when no performance requirement has been specified, and
d) the processes to be followed when a performance requirement has been specified but has not
been met.
— The number of pre-clinical evaluations (bench tests) to be performed has been greatly increased
in 7.2.2. For some of the tests, a performance requirement has been specified. For some of the
tests no performance requirement has been specified and, in these cases, a new requirement has
been added, namely the requirement to demonstrate that the performance of the implant under
evaluation is the same or better than that of a reference implant. If no reference implant exists, a
sequence of alternative options has been specified. These alternative options are also available in
the case where there is a performance requirement, which is not met by the implant being tested.
— A new clinical investigation subclause has been added in 7.3, with several requirements which
specify the circumstances in which a clinical investigation can be required.
— A new post-market surveillance subclause has been added in 7.4, which references the requirements
in ISO 21534:2007, 7.4.
— Several new marking requirements have been specified in 11.4.
— A note has been added in 11.6 which states that in some jurisdictions there is the option to provide
the instructions for use in electronic instead of paper format.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
v
© ISO 2023 – All rights reserved
---------------------- Page: 5 ----------------------
ISO/FDIS 21536:2023(E)
Introduction
There are three levels of standards dealing with nonactive surgical implants. These are as follows,
with level 1 being the highest:
— level 1: general requirements for non-active surgical implants and instrumentation used in
association with implants;
— level 2: particular requirements for families of non-active surgical implants;
— level 3: specific requirements for types of non-active surgical implant.
This document is a level 3 standard and contains requirements applying specifically to knee joint
replacements.
The level 1 standard, ISO 14630, contains requirements that apply to all non-active surgical implants. It
also indicates that there are additional requirements in the level 2 and level 3 standards.
The level 2 standards apply to more restricted sets or families of implants such as those designed for
use in osteosynthesis, cardiovascular surgery or joint replacement. For joint replacement implants, the
level 2 standard is ISO 21534.
To address all requirements, it is recommended that a standard of the lowest available level be consulted
first.
vi
© ISO 2023 – All rights reserved
---------------------- Page: 6 ----------------------
FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 21536:2023(E)
Non-active surgical implants — Joint replacement implants
— Specific requirements for knee-joint replacement
implants
1 Scope
This document specifies requirements for knee-joint replacement implants. Regarding safety, this
document specifies requirements for intended performance, design attributes, materials, design
evaluation, manufacture, sterilization, packaging, information supplied by the manufacturer and
methods of test.
This document applies to both total and partial knee joint replacement implants. It applies to these
replacements both with and without the replacement of the patella-femoral joint. It applies to
components made of metallic and nonmetallic materials.
This document applies to a wide variety of knee replacement implants, but for some specific knee
replacement implant types, some considerations, not specifically covered in this document, can be
applicable. Further details are given in 7.2.1.2.
The requirements which are specified in this document are not intended to require the re-design or re-
testing of implants which have been legally marketed and for which there is a history of sufficient and
safe clinical use. For such implants, compliance with this document can be demonstrated by providing
evidence of the implant’s sufficient and safe clinical use.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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.
ISO 58341, Implants for surgery — Ultra-high-molecular-weight polyethylene — Part 1: Powder form
ISO 72071:2007, Implants for surgery — Components for partial and total knee joint prostheses — Part 1:
Classification, definitions and designation of dimensions
ISO 72072, Implants for surgery — Components for partial and total knee joint prostheses — Part 2:
Articulating surfaces made of metal, ceramic and plastics materials
ISO 109931, Biological evaluation of medical devices — Part 1: Evaluation and testing within a risk
management process
ISO 142431, Implants for surgery — Wear of total knee-joint prostheses — Part 1: Loading and
displacement parameters for wear-testing machines with load control and corresponding environmental
conditions for test
ISO 142432, Implants for surgery — Wear of total knee-joint prostheses — Part 2: Methods of measurement
ISO 142433, Implants for surgery — Wear of total knee-joint prostheses — Part 3: Loading and
displacement parameters for wear-testing machines with displacement control and corresponding
environmental conditions for test
ISO 142435, Implants for surgery — Wear of total knee prostheses — Part 5: Durability performance of
the patellofemoral joint
ISO 14630, Non-active surgical implants — General requirements
1
© ISO 2023 – All rights reserved
---------------------- Page: 7 ----------------------
ISO/FDIS 21536:2023(E)
ISO 148791, Implants for surgery — Total knee-joint prostheses — Part 1: Determination of endurance
properties of knee tibial trays
ISO 21534:2007, Non-active surgical implants — Joint replacement implants — Particular requirements
ASTM F648, Standard Specification for Ultra-High-Molecular-Weight Polyethylene Powder and Fabricated
Form for Surgical Implants
ASTM F1223, Standard Test Method for Determination of Total Knee Replacement Constraint
ASTM F2722, Standard Practice for Evaluating Mobile Bearing Knee Tibial Baseplate Rotational Stops
ASTM F2723, Standard Test Method for Evaluating Mobile Bearing Knee Tibial Baseplate/Bearing
Resistance to Dynamic Disassociation
ASTM F2724, Standard Test Method for Evaluating Mobile Bearing Knee Dislocation
ASTM F2777, Standard Test Method for Evaluating Knee Bearing (Tibial Insert) Endurance and Deformation
Under High Flexion
ASTM F3210, Standard Test Method for Fatigue Testing of Total Knee Femoral Components under Closing
Conditions
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 14630, ISO 21534 and
ISO 7207-1 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
femoral component
component of a total knee joint prosthesis (3.14), patella-femoral knee joint prosthesis, or uni-
compartmental knee joint prosthesis (3.16) intended to be secured to the femur to replace its articulating
surface(s)
3.2
maximum claimed flexion
highest amount of flexion the total knee joint prosthesis (3.14) or uni-compartmental knee joint prosthesis
(3.16) can achieve as claimed by the manufacturer based on the requirements defined in 7.2.2.11
Note 1 to entry: A higher amount of flexion than the maximum claimed flexion can exist based on computer aided
design (CAD) or implant shape considerations.
3.3
mobile-bearing component
component of a total or unicompartmental mobile-bearing knee joint prosthesis (3.4) which articulates
with both the femoral component (3.1) and the tibial tray (3.13)
Note 1 to entry: The mobile-bearing component can be manufactured as one component or a set of components,
in both cases intended to be assembled in the mobile-bearing knee joint prosthesis (3.4) by the user.
Note 2 to entry: The mobile-bearing component is usually a sub-component of the tibial component (3.11),
supported by the tibial tray (3.13).
Note 3 to entry: The mobile-bearing component can also be referred to as the meniscal component.
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ISO/FDIS 21536:2023(E)
[SOURCE: ISO 7207-1:2007, 3.2.10, modified — Note 1 to entry has been replaced and Notes 2 and 3 to
entry have been added.]
3.4
mobile-bearing knee joint prosthesis
total knee joint prosthesis (3.14) or uni-compartmental knee joint prosthesis (3.16) which allows relative
motion between the mobile-bearing component (3.3) and both the femoral component (3.1) and the tibial
tray (3.13)
[SOURCE: ISO 7207-1:2007, 3.1.6, modified — "knee joint prosthesis" has been added after "total" in the
definition and Note 1 to entry has been deleted.]
3.5
partial knee joint prosthesis
partial knee joint replacement
uni-compartmental knee joint prosthesis (3.16) or a set of components used to replace the femoral and
tibial articulating surfaces in the medial compartment of a knee joint and also the patellar and femoral
articulating surfaces in the patellafemoral compartment
Note 1 to entry: Implants which are intended to repair a cartilage focal defect(s) or to be used for a surgical
procedure like mosaicplasty are not partial knee joint prostheses for the purposes of this document.
3.6
patellar component
component of a total knee joint prosthesis (3.14) or partial knee joint prosthesis (3.5) or patellafemoral
knee joint prosthesis which is used to replace the articulating surface of the patella
Note 1 to entry: Patellar components can be monobloc or modular.
3.7
patellar tray
subcomponent of a modular patellar component (3.6) of a total knee joint prosthesis (3.14) used to
support and secure the patellar insert
[SOURCE: ISO 7207-1:2007, 3.2.14]
3.8
posterior stabilized tibial insert
tibial insert (3.12) with a centre post protruding superiorly or some other mechanism which interfaces
with the femoral component (3.1) to restrict anterior translation of the femoral component (3.1) when
the knee is in flexion
Note 1 to entry: The portion of the femoral component (3.1) interfacing with the tibial insert centre post is
sometimes referred to as the “cam”.
3.9
reference implant
legally-marketed implant which, when compared to the implant under evaluation, satisfies both of the
following conditions:
a) it has the same intended use, similar materials and a similar design with regard to the specific
dimensional or performance criteria under evaluation to address the same clinical and technical
requirements, and
b) there is evidence of successful clinical use in sufficient numbers; for a sufficient period of time; and,
at a minimum, without known or reasonably-known evidence of design or performance-related
recalls with regard to the specific dimensional or performance criteria under evaluation
Note 1 to entry: The term “reference” is not intended to imply that the implant under evaluation and the
reference implant are “equivalent” or that the reference implant is a “predicate” implant. This is because for some
regulatory authorities, the terms “equivalent” and “predicate” have a meaning which is beyond that intended by
the term “reference” as used in this document.
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ISO/FDIS 21536:2023(E)
Note 2 to entry: A reference implant is the comparison implant for dimensional or performance parameter(s)
under evaluation. Other characteristics of the reference implant shall be considered in order for the comparison
to be suitable, as in some situations there can be cross-effects. Ideally, for the majority of dimensional and
performance parameters, a single reference implant should be used for comparison to the implant under
evaluation. However, more than one reference implant may be used for comparison purposes, with adequate
scientific and clinical justification.
Note 3 to entry: Some regulatory authorities require that a reference implant is one that is legally marketed in
their own country or jurisdiction. This fact can be taken into account when selecting a reference implant for the
purposes of this document.
Note 4 to entry: There is no agreed upon interpretation for what constitutes “sufficient numbers” or a “sufficient
period of time” in the above definition. Typically, a determination of what constitutes “sufficient numbers” and a
“sufficient period of time” is demonstrated by using statistical methods and clinical judgement in the evaluation
of implant performance.
Note 5 to entry: A justification for a “similar material” may include information that although the materials are
not the same, the material(s) used for the implant under evaluation can be shown to perform similarly with
regard to the test or its underlying clinical concern.
Note 6 to entry: Examples of design features that can be taken into consideration when evaluating whether an
implant has a ‘similar design’ to the implant under evaluation include means of fixation, modularity, constraint,
key dimensions and shape, processing, surface topography, surface treatment, etc. A justification for a “similar
design” therefore may include information that although the designs are not the same, the design of the implant
under evaluation can be shown to perform similarly with regard to the test or its underlying clinical concern.
Note 7 to entry: The manufacturer is responsible for identifying the reference implant(s) in accordance with the
regulatory requirements in the jurisdictions where the implant under evaluation is to be marketed.
3.10
sufficient and safe clinical use
clinical use of a legally-marketed implant in sufficient numbers, for a sufficient period of time and, at a
minimum, without known or reasonably-known evidence of design or performance-related recalls
Note 1 to entry: There is no agreed interpretation for what constitutes “sufficient numbers” or “sufficient period
of time” in the above definition. Typically, these are demonstrated by using statistical methods and clinical
judgement in the evaluation of implant performance.
Note 2 to entry: Some regulatory authorities require that a legally-marketed implant is one which is legally
marketed in their country or jurisdiction.
Note 3 to entry: For a legally-marketed system of knee replacement implants, there can be evidence to
demonstrate sufficient and safe clinical use for some parts of the system (e.g. some components and some sizes)
but not for others. For those parts of the system for which there is sufficient evidence, the requirements of this
document relating to design and testing shall not apply. For those parts of the system for which there is not
sufficient evidence to demonstrate sufficient and safe clinical use the requirements of this document relating to
design and testing shall apply.
Note 4 to entry: The manufacturer is responsible for identifying the implant with sufficient and safe clinical use
...
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