ISO/TS 4549:2023

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 2023
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ii
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
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
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described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
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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
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
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 l
...