EN ISO 21536:2024

SLOVENSKI STANDARD
01-september-2024
Neaktivni kirurški vsadki (implantati) - Sklepne proteze - Posebne zahteve za
kolenske proteze (ISO 21536:2023)
Non-active surgical implants - Joint replacement implants - Specific requirements for
knee-joint replacement implants (ISO 21536:2023)
Nichtaktive chirurgische Implantate - Implantate zum Gelenkersatz - Spezielle
Anforderungen an Implantate für den Kniegelenkersatz (ISO 21536:2023)
Implants chirurgicaux non actifs - Implants de remplacement d'articulation - Exigences
spécifiques relatives aux implants de remplacement de l'articulation du genou (ISO
21536:2023)
Ta slovenski standard je istoveten z: EN ISO 21536:2024
ICS:
11.040.40 Implantanti za kirurgijo, Implants for surgery,
protetiko in ortetiko prosthetics and orthotics
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 21536
EUROPEAN STANDARD
NORME EUROPÉENNE
July 2024
EUROPÄISCHE NORM
ICS 11.040.40 Supersedes EN ISO 21536:2009 EN ISO
21536:2009/A1:2014
English Version
Non-active surgical implants - Joint replacement implants -
Specific requirements for knee-joint replacement implants
(ISO 21536:2023)
Implants chirurgicaux non actifs - Implants de Nichtaktive chirurgische Implantate - Implantate zum
remplacement d'articulation - Exigences spécifiques Gelenkersatz - Spezielle Anforderungen an Implantate
relatives aux implants de remplacement de für den Kniegelenkersatz (ISO 21536:2023)
l'articulation du genou (ISO 21536:2023)
This European Standard was approved by CEN on 4 June 2023.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATIO N

EUROPÄISCHES KOMITEE FÜR NORMUN G

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2024 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 21536:2024 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
Annex ZA (informative)  Relationship between this European standard and the General
Safety and Performance Requirements of Regulation (EU) 2017/745 aimed to be
covered. 4

European foreword
This document (EN ISO 21536:2024) has been prepared by Technical Committee ISO/TC 150 "Implants
for surgery" in collaboration with Technical Committee CEN/TC 285 “Non-active surgical implants” the
secretariat of which is held by DIN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by January 2025, and conflicting national standards shall
be withdrawn at the latest by January 2025.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 21536:2009, EN ISO 21536:2009/A1:2014.
This document has been prepared under a standardization request addressed to CEN by the European
Commission. The Standing Committee of the EFTA States subsequently approves these requests for its
Member States.
For the relationship with EU Legislation, see informative Annex ZA, which is an integral part of this
document.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 21536:2023 has been approved by CEN as EN ISO 21536:2024 without any modification.

Annex ZA
(informative)
Relationship between this European standard and the General Safety
and Performance Requirements of Regulation (EU) 2017/745 aimed to
be covered
This European Standard has been prepared under a Commission’s standardization request
“M/575” to provide one voluntary means of conforming to the General Safety and Performance
Requirements of Regulation (EU) 2017/745 of 5 April 2017 concerning medical devices [OJ L 117].
Once this standard is cited in the Official Journal of the European Union under that Regulation,
compliance with the normative clauses of this standard given in Table ZA.1 and application of the
edition of the normatively referenced standards as given in Table ZA.2 confers, within the limits of
the scope of this standard, a presumption of conformity with the corresponding General Safety and
Performance Requirements of that Regulation, and associated EFTA regulations.
Where a definition in this standard differs from a definition of the same term set out in Regulation
(EU) 2017/745, the differences shall be indicated in this Annex Z. For the purpose of using this
standard in support of the requirements set out in Regulation (EU) 2017/745, the definitions set
out in this Regulation prevail.
Where the European standard is an adoption of an International Standard, the scope of this
standard can differ from the scope of the European Regulation that it supports. As the scope of the
applicable regulatory requirements differ from nation to nation and region to region, the standard
can only support European regulatory requirements to the extent of the scope of the European
regulation for medical devices (EU) 2017/745).
For application of this European standard under Regulation (EU) 2017/745,
1 it is clarified that the third paragraph of the scope and the related subclause 7.2.1.2 are solely intended
to point out that additional testing not specified in this document can be required to ensure the safety
and efficacy of implants for which failure modes exist which were unknown at the time of drafting of
this document;
2 it is clarified that the fourth paragraph of the scope and related language in the first paragraphs of
Clauses 4, 5, 6 and 7 are intended to avoid unnecessary re-design or re-testing of implants which are
currently legally marketed in the European Union;
3 it is recognized that the normatively referenced ISO 7207-2:2011+Amd 1:2016+Amd 2:2020 itself
includes a reference to the withdrawn ISO 4288:1996 which has been replaced by ISO 21920-3:2021
and for application of this European standard under Regulation (EU) 2017/745 ISO 21920-3:2021 shall
be used instead of ISO 4288:1996;
4 it is recognized that the normatively referenced ISO 10993-1 includes a dated reference to ISO
14971:2007 which is outdated and for application of this European standard under Regulation (EU)
2017/745 the most recent European version EN ISO 14971:2019 + A11:2021 shall be used;
NOTE 1 Where a reference from a clause of this standard to the risk management process is made, the risk
management process needs to be in compliance with Regulation (EU) 2017/745. This means that risks have to be
‘reduced as far as possible’, ‘reduced to the lowest possible level’, ‘reduced as far as possible and appropriate’,
‘removed or reduced as far as possible’, ‘eliminated or reduced as far as possible’, ’removed or minimized as far as
possible’, or ‘minimized’, according to the wording of the corresponding General Safety and Performance
Requirement.
NOTE 2 The manufacturer’s policy for determining acceptable risk must be in compliance with General Safety
and Performance Requirements 1, 2, 3, 4, 5, 8, 9, 10, 11, 14, 16, 17, 18, 19, 20, 21 and 22 of the Regulation.
NOTE 3 When a General Safety and Performance Requirement does not appear in Table ZA.1, it means that it is
not addressed by this European Standard.
Table ZA.1 — Correspondence between this European standard and Annex I of Regulation (EU)
2017/745 [OJ L 117] and to system or process requirements including those relating to quality
management systems, risk management, post-market surveillance systems, clinical investigations,
clinical evaluation or post-market clinical follow-up

General Safety and
Clause(s) / sub-clause(s)
Performance Requirements
Remarks / Notes
of Regulation (EU)
of this EN
2017/745
10.1 (c) 10.1 (c) is covered as follows:
7.2.2.4 The durability of the
patellofemoral joint is covered
by 7.2.2.4.
7.2.2.5 The attachment of the tibial
insert to the tibial tray is
covered by 7.2.2.5.
7.2.2.6 The attachment of the patella
insert to the patellar tray is
covered by 7.2.2.6.
7.2.2.7 The resistance to dynamic
disassociation of mobile-
bearing knee components
from the tibial tray is covered
by 7.2.2.7.
7.2.2.9
The dislocation of mobile-
bearing knees is covered by
7.2.2.10
7.2.2.9.
The static and fatigue strength
of modular connections is
7.2.2.12
covered by 7.2.2.10.
The patellofemoral resistance
to lateral subluxation is
7.2.2.13 and 7.2.2.14
covered by 7.2.2.12.
The tibio-femoral and the
patella-femoral contact area
and pressure are covered by
7.2.2.13 and 7.2.2.14.
10.1 (f) 7.2.2 (all subclauses) 10.1 (f) is covered with the
exception of “ductility” by
7.2.2 (all subclauses).
10.1 (g) 5.2.2 and 5.2.3 10.1 (g) is covered with
respect to the surface finish by
5.2.2 and 5.2.3.
st
10.4.1 1 paragraph 7.2.2.2 and 7.2.2.3 10.4.1 is covered with respect
to wear of the bearings of
knee implants by 7.2.2.2 and
7.2.2.3 which require that the
bearings of knee joints shall
undergo wear testing and the
wear shall be the same or less
than the wear of a reference
implant.
23.2 (b) 11.2 23.2 (b) is covered with
respect to product type and
dimensions by 11.2.
23.4 (s) 11.5 23.4 (s) is covered with
respect to the information for
the patient by 11.5.
Table ZA.2 — Applicable Standards to confer presumption of conformity as described in this
Annex ZA
Column 1 Column 2 Column 3 Column 4
Reference in International
Title Corresponding
Clause 2 Standard Edition
European Standard
Edition
ISO 5834-1 ISO 5834-1:2019 Implants for surgery — Ultra- -
high-molecular-weight
polyethylene — Part 1:
Powder form
ISO 7207-1:2007 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 ISO 7207-2:2011 Implants for surgery — -
and ISO 7207- Components for partial and
2:2011/Amd 1:2016 total knee joint prostheses —
and ISO 7207- Part 2: Articulating surfaces
2:2011/Amd 2:2020 made of metal, ceramic and
plastics materials
ISO 10993-1 ISO 10993-1:2018 Biological evaluation of EN ISO 10993-1:2020
medical devices — Part 1:
Evaluation and testing within
a risk management process
ISO 14243-1 ISO 14243-1:2009 Implants for surgery — Wear -
and ISO 14243- of total knee-joint prostheses
1:2009/Amd 1:2020 — Part 1: Loading and
displacement parameters for
wear-testing machines with
load control and
corresponding environmental
conditions for test
ISO 14243-2 ISO 14243-2:2016 Implants for surgery — Wear -
of total knee-joint prostheses
— Part 2: Methods of
measurement
ISO 14243-3 ISO 14243-3:2014 Implants for surgery — Wear -
and ISO 14243- of total knee-joint prostheses
3:2014/Amd 1:2020 — Part 3: Loading and
displacement parameters for
wear-testing machines with
displacement control and
corresponding environmental
conditions for test
ISO 14243-5 ISO 14243-5:2019 Implants for surgery — Wear -
of total knee prostheses —
Part 5: Durability
performance of the
patellofemoral joint
ISO 14630 ISO 14630:2012 Non-active surgical implants EN ISO 14630:2012
— General requirements
ISO 14879-1 ISO 14879-1:2020 Implants for surgery — Total -
knee-joint prostheses — Part
1: Determination of
endurance properties of knee
tibial trays
ISO 21534:2007 ISO 21534:2007 Non-active surgical implants EN ISO 21534:2009
— Joint replacement implants
— Particular requirements
The documents listed in the Column 1 of Table ZA.2, in whole or in part, are normatively referenced in
this document, i.e. are indispensable for its application. The achievement of the presumption of
conformity is subject to the application of the edition of Standards as listed in Column 4 or, if no
European Standard Edition exists, the International Standard Edition given in  Column 2 of Table ZA.2.
WARNING 1 — Presumption of conformity stays valid only as long as a reference to this European
Standard is maintained in the list published in the Official Journal of the European Union. Users of this
standard should consult frequently the latest list published in the Official Journal of the European
Union.
WARNING 2 — Other Union legislation may be applicable to the product(s) falling within the scope of
this standard.
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 21536:2023(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
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
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
iii
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
iv
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.
v
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.
vi
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
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.
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
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).
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 (3.1
...