ISO/TS 4549:2023
(Main)Orthotics — Method for testing the reliability of microprocessor-controlled ankle moment units of ankle-foot orthoses
Orthotics — Method for testing the reliability of microprocessor-controlled ankle moment units of ankle-foot orthoses
This document specifies a method for testing the reliability of microprocessor-controlled ankle moment units of ankle-foot orthosis, moving in plantar- and dorsiflexion direction. This document specifies categories of locomotion profiles to be applied together with appropriate loading profiles, to generate plantar- and dorsiflexion ankle moment loads for the microprocessor-controlled ankle moment units. It also defines which measured outcome of the test allows to claim compliance to this document, and how the compliance is documented in the IFU. This document solely addresses the resistance of microprocessor-controlled ankle moment units in motion. Geometrical constrains like end stops, where motion is stopped instead of sustaining it, can be tested in repetitive quasi static tests instead. A method to derive test parameters for the reliability test of microprocessor-controlled ankle moment units is described. This document is applicable to unilateral ankle-foot orthoses and to bilateral jointed orthoses where either both joints are controlled or where one joint is controlled and the other is not controlled.
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TECHNICAL ISO/TS
SPECIFICATION 4549
First edition
2023-07
Orthotics — Method for testing
the reliability of microprocessor-
controlled ankle moment units of
ankle-foot orthoses
Reference number
ISO/TS 4549:2023(E)
© ISO 2023
---------------------- Page: 1 ----------------------
ISO/TS 4549:2023(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
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 2023 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/TS 4549:2023(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Designations and symbols . 2
5 Requirements . 3
5.1 General . 3
5.2 Definition of Test parameters . 3
5.2.1 General . 3
5.2.2 Test without integrated sensors . . 3
5.2.3 Example of a set of test levels . 4
5.3 Test preparation . 4
6 Set-up conditions . 5
6.1 General . 5
6.2 Coordinate system . 5
6.3 Leg dummy . 5
6.4 Loading of the leg dummy . 5
6.5 Essential properties of orthoses to test . 6
6.6 Vertical loading of the Orthoses . 6
6.7 Angular profile of the tilting plate . 6
7 Test procedure .8
7.1 Static test for motion resistance of the ankle joint dummy . 8
7.2 Cyclic test . 9
8 Test report . 9
9 Compliance .10
9.1 Compliance to motion resistance of the ankle joint dummy . 10
9.2 Compliance to cyclic test . 10
9.3 Identifier of Compliance . 10
9.3.1 General format . 11
Annex A (informative) Measurement system for the acquisition of load data of an orthosis
for the lower limbs .12
Bibliography .15
iii
© ISO 2023 – All rights reserved
---------------------- Page: 3 ----------------------
ISO/TS 4549:2023(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 168, Prosthetics and orthotics.
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.
iv
© ISO 2023 – All rights reserved
---------------------- Page: 4 ----------------------
ISO/TS 4549:2023(E)
Introduction
Orthoses of the lower limb are used to treat a wide variety of pathologies. To partly compensate
functional deficits, orthoses are used, which provide appropriate functions. The more functionality is
provided by orthoses, the more important their functional reliability is.
Structural strength of orthoses, supporting the limb by stabilizing its joints against motion, is as
important as stabilisation of movement of joints between limb segments, when mobility is aimed in
rehabilitation.
Testing reliability of the controlled ankle moment units of orthoses, which stabilise joint movement,
requires to introduce motion into the strength test.
The reliability of microprocessor-controlled ankle moment units of orthosis, supporting the anatomical
ankle joint in plantar- and dorsiflexion motion, can be tested by repetitively loading and driving the
ankle joint in an appropriate angular and force profile, resulting in the moment profile to test.
Current technologies for acquiring loading and motion-data of orthotic ankle joints in real use are the
basis to derive test conditions, which simulate repetitive loading for the microprocessor-controlled
ankle moment units in a laboratory environment.
Orthoses of the lower limb are operating aside the leg of the orthosis user. For testing the reliability of
microprocessor-controlled ankle moment units in a laboratory test, it is essential to mimic the orthosis
user's extremity in such a way, that the orthosis shows its functional capabilities and its reliability. The
chapter “leg dummy” in this document describes essential properties of the leg dummy, mimicking the
orthosis user's leg.
Covering high loading events during intended use, to be generated by the control elements repetitively
in the test, provides a safety factor also for lower loading scenarios of less demanding pathologies.
The Osaka Electro-Communication University in Japan has developed a system of miniaturised sensors
with associated data acquisition and data analysis, which can be integrated into an ankle-foot orthosis
to measure the multi-axial loading and angular movement of orthotic ankle joints. This system has
been used by 50 ankle-foot orthosis users to explore the assessment processes for the reliability of
microprocessor-controlled ankle moment elements provided in this document.
v
© ISO 2023 – All rights reserved
---------------------- Page: 5 ----------------------
TECHNICAL SPECIFICATION ISO/TS 4549:2023(E)
Orthotics — Method for testing the reliability of
microprocessor-controlled ankle moment units of ankle-
foot orthoses
1 Scope
This document specifies a method for testing the reliability of microprocessor-controlled ankle moment
units of ankle-foot orthosis, moving in plantar- and dorsiflexion direction.
This document specifies categories of locomotion profiles to be applied together with appropriate
loading profiles, to generate plantar- and dorsiflexion ankle moment loads for the microprocessor-
controlled ankle moment units. It also defines which measured outcome of the test allows to claim
compliance to this document, and how the compliance is documented in the IFU.
This document solely addresses the resistance of microprocessor-controlled ankle moment units in
motion. Geometrical constrains like end stops, where motion is stopped instead of sustaining it, can be
tested in repetitive quasi static tests instead.
A method to derive test parameters for the reliability test of microprocessor-controlled ankle moment
units is described.
This document is applicable to unilateral ankle-foot orthoses and to bilateral jointed orthoses where
either both joints are controlled or where one joint is controlled and the other is not controlled.
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 22675:2016, Prosthetics — Testing of ankle-foot devices and foot units — Requirements and test
methods
ISO 22523:2006, External limb prostheses and external orthoses — Requirements and test methods
3 Terms and definitions
For the purposes of this document, the following terms and definitions 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
microprocessor-controlled ankle moment unit
flexing and extending element, bearing loads and generating ankle moment, located medial or lateral to
the anatomical upper ankle joint, providing or varying ankle moment when moved in the direction of
dorsiflexion and plantarflexion
1
© ISO 2023 – All rights reserved
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ISO/TS 4549:2023(E)
3.2
passive ankle joint
flexing and extending element, located preferably medial to the ankle joint, mainly bearing loads
parallel to its plane of motion
Note 1 to entry: The passive ankle joint stabilises the controlled ankle moment unit on the opposite side of the
anatomical ankle joint with regard to forces and rotational moments, especially in frontal- and transversal plane.
3.3
load distribution ring
rigid ring located above the proximal end of the orthosis, to distribute the test force on the orthosis
upper brace and to avoid pressure spots
3.4
shank element
strait rod or tube, located in the tibia region of an anatomical leg, which transfers the load from the
dummy's knee to the dummy's foot; it also guides the load distribution ring and aligns the ring in the
transverse plane on a level, suitable to load the interface component of the orthoses parallel to the
shank element
3.5
outer shank element
ring, connected to the lower surface of the load distribution ring, which positions the upper brace of the
orthosis relative to the shank element
Note 1 to entry: The height of the ring is adapted to the height of the upper brace of the orthosis.
Note 2 to entry: The contour and compliance of the outer shank element may not stabilize the orthotic frame with
regards to its deflection in either plane.
3.6
orthotic frame
connecting element(s) which connect the upper brace of the orthosis to the ankle joint element(s)
Note 1 to entry: The frame can be designed by using side bars or by a brace structure.
3.7
leg dummy
an assembly of modified prosthetic componentry, mimicking the lower leg of the user of an orthosis in
the test setup
3.8
ankle moment measured
readout of the ankle moment value, measured with calibrated and validated sensors, which are
integrated in the orthotic systems bearing structure for studies and/or for testing or which are part of
the microprocessor-controlled ankle moment units
4 Designations and symbols
The designations and symbols of all relevant test forces and moments are listed in Table 1.
Table 1 — Designations and symbols of test forces and moments
Designation Symbol
Test force F
u
st nd
1 and 2 maximum value of pulsating test force F , F
1cmax 2cmax
Minimum moment measured M
min
Maximum moment measured M
max
2
© ISO 2023 – All rights reserved
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ISO/TS 4549:2023(E)
5 Requirements
5.1 General
The selection of test levels and test force related to the intended use are defined by the manufacturer/
submitter with justification and documented in the test report prior testing (see Clause 8).
In order to claim compliance with this document, all relevant settings in the specific adjustments shall
be tested and the strength requirements specified in ISO 22523:2006, 4.4 shall be met.
The selection criteria for the samples to be tested shall be in accordance with ISO 22675.
In order to test the reliability of microprocessor-controlled ankle moment units, the ankle joint of the
leg dummy shall not limit the motion of the orthotic joint(s) under load. Suitability of an ankle joint in
the leg dummy shall be demonstrated in the static test for motion-resistance of the ankle joint dummy,
defined in 7.1 before conducting the cyclic test.
5.2 Definition of Test parameters
5.2.1 General
Depending on the intended use, the manufacturer/submitter provides sufficient information to derive
the appropriate test parameters by defining angular range, loading parameters and cycle number
to generate the ankle moment loading of the microprocessor-controlled ankle moment unit in the
laboratory test for the test lab. This information can be gained with orthoses which are equipped with
calibrated and validated sensors, worn by the intended user group, performing the intended use in a
representative size of the user group. The orthoses used to acquire the data
...
ISO/DTS 4549:20222023(E)
ISO TC 168/WG 3
Date: 2022-10-312023-01-29
Orthotics — Method for testing the reliability of microprocessor-controlled ankle moment units
of ankle-foot orthoses
DTS stage
This document is not an ISO International Standard. It is distributed for review and comment. It is subject to
change without notice and may not be referred to as an International Standard.
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 supporting documentation.
© ISO 2022 – All rights reserved
---------------------- Page: 1 ----------------------
© ISO 2022
---------------------- Page: 2 ----------------------
ISO/DTS 4549:20222023(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.orgwww.iso.org
Published in Switzerland
© ISO 2022 – All rights reserved
iv © ISO 2023 – All rights reserved
---------------------- Page: 3 ----------------------
ISO/DTS 4549:20222023 (E)
Contents
Foreword . iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms . 2
5 Requirements . 3
5.1 General . 3
5.2 Definition of Test parameters . 3
5.2.1 Test without integrated sensors . 3
5.2.2 Example of a set of test levels . 4
5.3 Test preparation . 4
6 Set-up conditions . 5
6.1 Coordinate system. 5
6.2 Leg dummy . 5
6.3 Loading of the leg dummy . 6
6.4 Essential properties of orthoses to test . 6
6.5 Vertical loading of the Orthoses . 6
6.6 Angular profile of the tilting plate . 6
7 Test procedure . 8
7.1 Static test for motion resistance of the ankle joint dummy . 8
7.2 Cyclic test . 9
8 Test report . 9
9 Compliance . 11
9.1 Compliance to motion resistance of the ankle joint dummy . 11
9.2 Compliance to cyclic test . 11
9.3 Identifier of Compliance . 11
9.3.1 General format . 11
Annex A (informative) Measurement system for the acquisition of load data of an orthosis
for the lower limbs . 12
© ISO 2022 – All rights reserved © ISO 2023 – All rights v
reserved
---------------------- Page: 4 ----------------------
ISO/DTS 4549:20222023(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 168, Prosthetics and orthotics.
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.
© ISO 2022 – All rights reserved
vi © ISO 2023 – All rights reserved
---------------------- Page: 5 ----------------------
ISO/DTS 4549:20222023 (E)
Introduction
Orthoses of the lower limb are used to treat a wide variety of pathologies. To partly compensate
functional deficits, orthoses are used, which provide appropriate functions. The more functionality is
provided by orthoses, the more important their functional reliability is.
Structural strength of orthoses, supporting the limb by stabilizing its joints against motion, is as
important as stabilisation of movement of joints between limb segments, when mobility is aimed in
rehabilitation.
Testing reliability of the controlled ankle moment units of orthoses, which stabilise joint movement,
requires to introduce motion into the strength test.
The reliability of microprocessor-controlled ankle moment units of orthosis, supporting the anatomical
ankle joint in plantar- and dorsiflexion motion, can be tested by repetitively loading- and driving the ankle
joint in an appropriate angular- and force profile, resulting in the moment profile to test.
Current technologies for acquiring loading and motion-data of orthotic ankle joints in real use are the
basis to derive test conditions, which simulate repetitive loading for the microprocessor-controlled ankle
moment units in a laboratory environment.
Orthoses of the lower limb are operating aside the leg of the orthosis user. For testing the reliability of
microprocessor-controlled ankle moment units in a laboratory test, it is essential, to mimic the orthosis
usersuser's extremity in such a way, that the orthosis shows its functional capabilities and it´sits
reliability. The chapter “leg dummy” in this document describes essential properties of the leg dummy,
mimicking the orthosis usersuser's leg.
Covering high loading events during intended use, to be generated by the control elements repetitively
in the test, provides a safety factor, also for lower loading scenarios of less demanding pathologies.
The Osaka Electro-Communication University in Japan has developed a system of miniaturised sensors
with associated data acquisition and data analysis, which can be integrated into an ankle-foot orthosis to
measure the multi-axial loading and angular movement of orthotic ankle joints. This system has been
used by 50 ankle-foot orthosis users to explore the process of assessment ofprocesses for the reliability
of microprocessor-controlled ankle moment elements, provided in this document.
© ISO 2022 – All rights reserved © ISO 2023 – All rights vii
reserved
---------------------- Page: 6 ----------------------
TECHNICAL SPECIFICATION ISO/DTS 4549:2022(E)
Orthotics — Method for testing the reliability of microprocessor-
controlled ankle moment units of ankle-foot orthoses
1 Scope
This document specifies a method for testing the reliability of microprocessor-controlled ankle moment
units of ankle-foot orthosis, moving in plantar- and dorsiflexion direction.
This document specifies categories of locomotion profiles to be applied together with appropriate loading
profiles, to generate plantar- and dorsiflexion ankle moment loads for the microprocessor-controlled
ankle moment units. It also defines, which measured outcome of the test allows to claim compliance to
this document, and how the compliance is documented in the IFU.
This document solely addresses the resistance of microprocessor-controlled ankle moment units in
motion. Geometrical constrains like end stops, where motion is stopped instead of sustaining it, can be
tested in repetitive quasi static tests instead.
A method is described, how to derive test parameters for the reliability test of microprocessor-controlled
ankle moment units. is described.
This document is applicable to unilateral ankle-foot orthoses and to bilateral jointed orthoses where
either both joints are either controlled or where one joint is controlled and the other is not controlled.
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 22675:20062016, Prosthetics — Testing of ankle-foot devices and foot units — Requirements and test
methods
ISO 10328, Prosthetics — Structural testing of lower-limb prostheses — Requirements and test methods
ISO ISO 22523:2006, External limb prostheses and external orthoses — Requirements and test methods
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp
— IEC Electropedia: available at httphttps://www.electropedia.org/
Field Code Changed
3.1
microprocessor-controlled ankle moment unit
© ISO 2022 – All rights reserved 1
---------------------- Page: 7 ----------------------
ISO/DTS 4549:2023(E)
flexing and extending element, bearing loads and generating ankle moment, located medial or lateral to
the anatomical upper ankle joint, providing or varying ankle moment when moved in the direction of
dorsiflexion and plantarflexion.
3.2
passive ankle joint
flexing and extending element, located preferably medial to the ankle joint, mainly bearing loads parallel
to its plane of motion
Note to entry: The passive ankle joint stabilises the controlled ankle moment unit on the opposite side of the
anatomical ankle joint with regard to forces and rotational moments, especially in frontal- and transversal plane.
3.3
load distribution ring
rigid ring, located above the proximal end of the orthosis, to distribute the test force on the orthosis upper
brace and to avoid pressure spots.
3.4
shank element
strait rod or tube, located in the tibia region of an anatomical leg, which transfers the load from the
dummy's knee to the dummy's foot. It; it also guides the load distribution ring and aligns the ring in the
transverse plane on a level, suitable to load the interface component of the orthoses parallel to the shank
element.
3.5
outer shank element
ring, connected to the lower surface of the load distribution ring, which positions the upper brace of the
orthosis relative to the shank element
Note 1 to entry: The height of the ring is adapted to the height of the upper brace of the orthosis.
Note 2 to entry: The contour and compliance of the outer shank element may not stabilize the orthotic frame with
regards to its deflection in either plane.
3.6
orthotic frame
connecting element(s) which connect the upper brace of the orthosis to the ankle joint element(s). )
Note 1 to entry: The frame can be designed by using side bars or by a brace structure.
3.7
leg dummy
an assembly of modified prosthetic componentry, mimicking the lower leg of the user of an orthosis in
the test setup
3.8
ankle moment measured
readout of the ankle moment value, measured with calibrated and validated sensors, which are integrated
in the orthotic systems bearing structure for studies and/or for testing or which are part of the
microprocessor-controlled ankle moment units
© ISO 2022 – All rights reserved
2 © ISO 2023 – All rights reserved
---------------------- Page: 8 ----------------------
ISO/DTS 4549:2022 (E)
4 DesignationDesignations and symbols
The designations and symbols of all relevant test forces and moments are listed in Table 1.
Table 1 — Designations and symbols of test forces and moments
Designation Symbol
Test force FF
u
st nd
1 and 2 maximum value of pulsating test force F , F
1cmax 2cmax
Minimum moment measured M
min
Maximum moment measured
M
max
5 Requirements
5.1 General
The selection of test levels and test force related to the intended use, are defined by the
manufacturer/submitter with justification and documented in the test report prior testing (see Clause 8).
In order to claim compliance with this document, all relevant settings in the specific adjustments shall be
tested and the strength requirements specified in ISO 22523:2006, 4.4 shall be met.
The selection criteria for the samples to be tested shall be in accordance with ISO 22675.
In order to test the reliability of microprocessor-controlled ankle moment units, the ankle joint of the leg
dummy shall not limit the motion of the orthotic joint(s) under load. Suitability of an ankle joint in the leg
dummy shall be demonstrated in the static test for motion-resistance of the ankle joint dummy, defined
in 7.1 before conducting the cyclic test.
5.2 Definition of Test parameters
5.2.1 General
Depending toon the intended use, the manufacturer/submitter provides sufficient information to derive
the appropriate test parameters by defining angular range, loading parameters and cycle number to
generate the ankle moment loading of the microprocessor-controlled ankle moment unit in the
laboratory test for the test lab. This information can be gained with orthoses which are equipped with
calibrated and validated sensors, worn by the intended user group, performing the intended use in a
representative size of the user group. The orthoses used to acquire the data in use, fitted to the leg dummy
(see below) also provides the data which is needed to adapt the angular range and the test load profile to
simulate the ankle moment loadings for further test samples. The chosen test force reference value (F),
F , shall be documented in the test report and indicated on the identifier.
1cmax
If parameters are derived in studies, using criteria of lower levels where higher levels are intended for
use, the levels of the intended use apply.
If parameters derived in studies are between the defined test levels of this document, the reliability of
the motion resistance has to be tested on the next higher test level.
Test forces and Testtest loads already are includinginclude a safety factor for walking on level ground. A
higher safety margin shall be tested by testing on a single higher level or on a variety of higher test levels.
© ISO 2022 – All rights reserved © ISO 2023 – All rights 3
reserved
---------------------- Page: 9 ----------------------
ISO/DTS 4549:2023(E)
5.2.15.2.2 Test without integrated sensors
For testing test samples from normal production, where integrated sensors are influencinginfluence the
structure of the orthosis, equivalent sensors shall be installed in the test setup, which provide an
equivalent to the ankle moment measured, proportional to the ankle moment. These sensors are
val
...
FINAL
TECHNICAL ISO/DTS
DRAFT
SPECIFICATION 4549
ISO/TC 168
Orthotics — Method for testing
Secretariat: DIN
the reliability of microprocessor-
Voting begins on:
2023-03-15 controlled ankle moment units of
ankle-foot orthoses
Voting terminates on:
2023-05-10
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/DTS 4549:2023(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/DTS 4549:2023(E)
FINAL
TECHNICAL ISO/DTS
DRAFT
SPECIFICATION 4549
ISO/TC 168
Orthotics — Method for testing
Secretariat: DIN
the reliability of microprocessor-
Voting begins on:
controlled ankle moment units of
ankle-foot orthoses
Voting terminates on:
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
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/DTS 4549:2023(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/DTS 4549:2023(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Designations and symbols . 2
5 Requirements . 3
5.1 General . 3
5.2 Definition of Test parameters . 3
5.2.1 General . 3
5.2.2 Test without integrated sensors . . 3
5.2.3 Example of a set of test levels . 4
5.3 Test preparation . 4
6 Set-up conditions . 5
6.1 General . 5
6.2 Coordinate system . 5
6.3 Leg dummy . 5
6.4 Loading of the leg dummy . 5
6.5 Essential properties of orthoses to test . 6
6.6 Vertical loading of the Orthoses . 6
6.7 Angular profile of the tilting plate . 6
7 Test procedure .8
7.1 Static test for motion resistance of the ankle joint dummy . 8
7.2 Cyclic test . 9
8 Test report . 9
9 Compliance .10
9.1 Compliance to motion resistance of the ankle joint dummy . 10
9.2 Compliance to cyclic test . 10
9.3 Identifier of Compliance . 10
9.3.1 General format . 10
Annex A (informative) Measurement system for the acquisition of load data of an orthosis
for the lower limbs .12
Bibliography .15
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ISO/DTS 4549:2023(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 nongovernmental, 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 168, Prosthetics and orthotics.
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/DTS 4549:2023(E)
Introduction
Orthoses of the lower limb are used to treat a wide variety of pathologies. To partly compensate
functional deficits, orthoses are used, which provide appropriate functions. The more functionality is
provided by orthoses, the more important their functional reliability is.
Structural strength of orthoses, supporting the limb by stabilizing its joints against motion, is as
important as stabilisation of movement of joints between limb segments, when mobility is aimed in
rehabilitation.
Testing reliability of the controlled ankle moment units of orthoses, which stabilise joint movement,
requires to introduce motion into the strength test.
The reliability of microprocessor-controlled ankle moment units of orthosis, supporting the anatomical
ankle joint in plantar- and dorsiflexion motion, can be tested by repetitively loading and driving the
ankle joint in an appropriate angular and force profile, resulting in the moment profile to test.
Current technologies for acquiring loading and motion-data of orthotic ankle joints in real use are the
basis to derive test conditions, which simulate repetitive loading for the microprocessorcontrolled
ankle moment units in a laboratory environment.
Orthoses of the lower limb are operating aside the leg of the orthosis user. For testing the reliability of
microprocessor-controlled ankle moment units in a laboratory test, it is essential to mimic the orthosis
user's extremity in such a way, that the orthosis shows its functional capabilities and its reliability. The
chapter “leg dummy” in this document describes essential properties of the leg dummy, mimicking the
orthosis user's leg.
Covering high loading events during intended use, to be generated by the control elements repetitively
in the test, provides a safety factor also for lower loading scenarios of less demanding pathologies.
The Osaka Electro-Communication University in Japan has developed a system of miniaturised sensors
with associated data acquisition and data analysis, which can be integrated into an ankle-foot orthosis
to measure the multi-axial loading and angular movement of orthotic ankle joints. This system has
been used by 50 ankle-foot orthosis users to explore the assessment processes for the reliability of
microprocessorcontrolled ankle moment elements provided in this document.
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TECHNICAL SPECIFICATION ISO/DTS 4549:2023(E)
Orthotics — Method for testing the reliability of
microprocessor-controlled ankle moment units of ankle-
foot orthoses
1 Scope
This document specifies a method for testing the reliability of microprocessor-controlled ankle moment
units of ankle-foot orthosis, moving in plantar- and dorsiflexion direction.
This document specifies categories of locomotion profiles to be applied together with appropriate
loading profiles, to generate plantar- and dorsiflexion ankle moment loads for the microprocessor-
controlled ankle moment units. It also defines which measured outcome of the test allows to claim
compliance to this document, and how the compliance is documented in the IFU.
This document solely addresses the resistance of microprocessor-controlled ankle moment units in
motion. Geometrical constrains like end stops, where motion is stopped instead of sustaining it, can be
tested in repetitive quasi static tests instead.
A method to derive test parameters for the reliability test of microprocessor-controlled ankle moment
units is described.
This document is applicable to unilateral anklefoot orthoses and to bilateral jointed orthoses where
either both joints are controlled or where one joint is controlled and the other is not controlled.
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 22675:2016, Prosthetics — Testing of ankle-foot devices and foot units — Requirements and test
methods
ISO 22523:2006, External limb prostheses and external orthoses — Requirements and test methods
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological 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
microprocessor-controlled ankle moment unit
flexing and extending element, bearing loads and generating ankle moment, located medial or lateral to
the anatomical upper ankle joint, providing or varying ankle moment when moved in the direction of
dorsiflexion and plantarflexion
1
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ISO/DTS 4549:2023(E)
3.2
passive ankle joint
flexing and extending element, located preferably medial to the ankle joint, mainly bearing loads
parallel to its plane of motion
Note 1 to entry: Note to entry: The passive ankle joint stabilises the controlled ankle moment unit on the
opposite side of the anatomical ankle joint with regard to forces and rotational moments, especially in frontal-
and transversal plane.
3.3
load distribution ring
rigid ring located above the proximal end of the orthosis, to distribute the test force on the orthosis
upper brace and to avoid pressure spots
3.4
shank element
strait rod or tube, located in the tibia region of an anatomical leg, which transfers the load from the
dummy's knee to the dummy's foot; it also guides the load distribution ring and aligns the ring in the
transverse plane on a level, suitable to load the interface component of the orthoses parallel to the
shank element
3.5
outer shank element
ring, connected to the lower surface of the load distribution ring, which positions the upper brace of the
orthosis relative to the shank element
Note 1 to entry: The height of the ring is adapted to the height of the upper brace of the orthosis.
Note 2 to entry: The contour and compliance of the outer shank element may not stabilize the orthotic frame with
regards to its deflection in either plane.
3.6
orthotic frame
connecting element(s) which connect the upper brace of the orthosis to the ankle joint element(s)
Note 1 to entry: The frame can be designed by using side bars or by a brace structure.
3.7
leg dummy
an assembly of modified prosthetic componentry, mimicking the lower leg of the user of an orthosis in
the test setup
3.8
ankle moment measured
readout of the ankle moment value, measured with calibrated and validated sensors, which are
integrated in the orthotic systems bearing structure for studies and/or for testing or which are part of
the microprocessorcontrolled ankle moment units
4 Designations and symbols
The designations and symbols of all relevant test forces and moments are listed in Table 1.
Table 1 — Designations and symbols of test forces and moments
Designation Symbol
Test force F
u
st nd
1 and 2 maximum value of pulsating test force F , F
1cmax 2cmax
Minimum moment measured M
min
Maximum moment measured M
max
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ISO/DTS 4549:2023(E)
5 Requirements
5.1 General
The selection of test levels and test force related to the intended use are defined by the manufacturer/
submitter with justification and documented in the test report prior testing (see Clause 8).
In order to claim compliance with this document, all relevant settings in the specific adjustments shall
be tested and the strength requirements specified in ISO 22523:2006, 4.4 shall be met.
The selection criteria for the samples to be tested shall be in accordance with ISO 22675.
In order to test the reliability of microprocessor-controlled ankle moment units, the ankle joint of the
leg dummy shall not limit the motion of the orthotic joint(s) under load. Suitability of an ankle joint in
the leg dummy shall be demonstrated in the static test for motion-resistance of the ankle joint dummy,
defined in 7.1 before conducting the cyclic test.
5.2 Definition of Test parameters
5.2.1 General
Depending on the i
...
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