ASTM F2996-20

Standard Practice for Finite Element Analysis (FEA) of Non-Modular Metallic Orthopaedic Hip Femoral Stems

SIGNIFICANCE AND USE
3.1 This practice is applicable to the calculation of stresses seen on a femoral hip stem when loaded in a manner described in ISO 7206-4 (2010). This method can be used to establish the worst-case size for a particular implant. When stresses calculated using this practice were compared to the stresses measured from physical strain gauging techniques performed at two laboratories using two different methods, the results correlated to within 8 %.  
3.2 This test method can be used to estimate the effects of design variables on the stress and strain of metallic hip femoral stems in a set-up mimicking that described in ISO 7206-4 (2010).
SCOPE
1.1 This practice establishes requirements and considerations for the numerical simulation of non-modular (that is, limited to monolithic stems with only a femoral head/trunnion taper interface) metallic orthopaedic hip stems using Finite Element Analysis (FEA) techniques for the estimation of stresses and strains. This standard is only applicable to stresses below the yield strength, as provided in the material certification.  
1.2 Purpose—This practice establishes requirements and considerations for the development of finite element models to be used in the evaluation of non-modular metallic orthopaedic hip stem designs for the purpose of prediction of the static implant stresses and strains. This procedure can be used for worst-case assessment within a series of different sizes of the same implant design to reduce the physical test burden. Recommended procedures for performing model checks and verification are provided to help determine if the analysis follows recommended guidelines. Finally, the recommended content of an engineering report covering the mechanical simulation is presented.  
1.3 Limits—This practice is limited in discussion to the static structural analysis of non-modular metallic orthopaedic hip stems (which excludes the prediction of fatigue strength).  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 14-Jun-2020
• ICS: 11.040.40 - Implants for surgery, prosthetics and orthotics
• Technical Committee: F04 - Medical and Surgical Materials and Devices
• Drafting Committee: F04.22 - Arthroplasty

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: F2996 − 20
Standard Practice for
Finite Element Analysis (FEA) of Non-Modular Metallic
1
Orthopaedic Hip Femoral Stems
This standard is issued under the fixed designation F2996; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
1.1 This practice establishes requirements and consider-
Barriers to Trade (TBT) Committee.
ations for the numerical simulation of non-modular (that is,
limited to monolithic stems with only a femoral head/trunnion
2. Referenced Documents
taper interface) metallic orthopaedic hip stems using Finite
Element Analysis (FEA) techniques for the estimation of 2
2.1 ISO Standards:
stresses and strains.This standard is only applicable to stresses
ISO 7206-4 (2010) Implants for Surgery—Partial and Total
below the yield strength, as provided in the material certifica-
HipJointProstheses—Part4:DeterminationofEndurance
tion.
Properties and Performance of Stemmed Femoral Com-
1.2 Purpose—This practice establishes requirements and ponents
considerations for the development of finite element models to
be used in the evaluation of non-modular metallic orthopaedic
3. Significance and Use
hip stem designs for the purpose of prediction of the static
3.1 This practice is applicable to the calculation of stresses
implant stresses and strains. This procedure can be used for
seen on a femoral hip stem when loaded in a manner described
worst-case assessment within a series of different sizes of the
inISO7206-4(2010).Thismethodcanbeusedtoestablishthe
same implant design to reduce the physical test burden.
worst-case size for a particular implant. When stresses calcu-
Recommended procedures for performing model checks and
lated using this practice were compared to the stresses mea-
verification are provided to help determine if the analysis
sured from physical strain gauging techniques performed at
follows recommended guidelines. Finally, the recommended
two laboratories using two different methods, the results
content of an engineering report covering the mechanical
correlated to within 8 %.
simulation is presented.
3.2 This test method can be used to estimate the effects of
1.3 Limits—This practice is limited in discussion to the
design variables on the stress and strain of metallic hip femoral
static structural analysis of non-modular metallic orthopaedic
stems in a set-up mimicking that described in ISO 7206-4
hip stems (which excludes the prediction of fatigue strength).
(2010).
1.4 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this 4. Geometric Data
standard.
4.1 Finite element models are based on a geometric repre-
1.5 This standard does not purport to address all of the
sentation of the device being studied. The source of the
safety concerns, if any, associated with its use. It is the
geometricdetailscanbeobtainedfromdrawings,solidmodels,
responsibility of the user of this standard to establish appro-
preliminary sketches, or any other source consistent with
priate safety, health, and environmental practices and deter-
defining the model geometry. In building the finite element
mine the applicability of regulatory limitations prior to use.
model, certain geometric details may be omitted from the
1.6 This international standard was developed in accor-
orthopaedic implant geometry shown in the computer-aided
dance with internationally recognized principles on standard-
design (CAD) model if it is determined that they are not
ization established in the Decision on Principles for the
relevant to the intended analysis. Engineering judgment shall
be exercised to establish the extent of model simplification and
1 shall be justified.
ThispracticeisunderthejurisdictionofASTMCommitteeF04onMedicaland
Surgical Materials and Devices and is the direct responsibility of Subcommittee
F04.22 on Arthroplasty.
Current edition approved June 15, 2020. Published August 2020. Originally
2
approved in 2013. Last previous edition approved in 2013 as F2996 – 13. DOI: Available from International Organization for Standardization (ISO), 1, ch. de
10.1520/F2996-20. la Voie-Creuse, CP 56, CH-1211 Geneva 20, Switzerland, http://www.iso.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: F2996 − 13 F2996 − 20
Standard Practice for
Finite Element Analysis (FEA) of Non-Modular Metallic
1
Orthopaedic Hip Femoral Stems
This standard is issued under the fixed designation F2996; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This practice establishes requirements and considerations for the numerical simulation of non-modular (that is, limited to
monolithic stems with only a femoral head / trunnion head/trunnion taper interface) metallic orthopaedic hip stems using Finite
Element Analysis (FEA) techniques for the estimation of stresses and strains. This standard is only applicable to stresses below
the yield strength, as provided in the material certification.
1.2 Purpose—This practice establishes requirements and considerations for the development of finite element models to be used
in the evaluation of non-modular metallic orthopaedic hip stem designs for the purpose of prediction of the static implant stresses
and strains. This procedure can be used for worst case worst-case assessment within a familyseries of implant sizes to provide
efficiencies in the amount of physical testing to be conducted. different sizes of the same implant design to reduce the physical test
burden. Recommended procedures for performing model checks and verification are provided to help determine if the analysis
follows recommended guidelines. Finally, the recommended content of an engineering report covering the mechanical simulation
is presented.
1.3 Limits—This practice is limited in discussion to the static structural analysis of non-modular metallic orthopaedic hip stems
(which excludes the prediction of fatigue strength).
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.6 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2
2.1 ISO Standards:
ISO 7206-4 (2010) Implants for Surgery—Partial and Total Hip Joint Prostheses—Part 4: Determination of Endurance
Properties and Performance of Stemmed Femoral Components
1
This practice is under the jurisdiction of ASTM Committee F04 on Medical and Surgical Materials and Devices and is the direct responsibility of Subcommittee F04.22
on Arthroplasty.
Current edition approved July 15, 2013June 15, 2020. Published August 2013August 2020. Originally approved in 2013. Last previous edition approved in 2013 as
F2996 – 13. DOI: 10.1520/F2996-13.10.1520/F2996-20.
2
Available from International Organization for Standardization (ISO), 1, ch. de la Voie-Creuse, CP 56, CH-1211 Geneva 20, Switzerland, http://www.iso.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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F2996 − 20
3. Significance and Use
3.1 This practice is applicable to the calculation of stresses seen on a femoral hip stem when loaded in a manner described in ISO
7206-4 (2010). This method can be used to establish the worst case worst-case size for a particular implant. When stresses
calculated using this practice were compared to the stresses measured from physical strain gauging techniques performed at two
laboratories using two different methods, the results correlated to within 8 %.
3.2 This test method can be used to estimate the effects of design variables on the stress and strain of metallic hip femoral stems
in a set-up mimicking that described in ISO 7206-4 (2010).
4. Geometric Data
4.1 Finite element models are based on a geometric representation of the device being studied. The source of the geometric details
can be obtained from drawings, solid models, preliminary sketches, or any other source consisten
...