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Biomechanical analysis of staples for epiphysiodesis

Abstract

Limb asymmetry can, and often does, cause various health problems. Blount bone staples (clips) are used to correct such uneven growth. This article analyzes the performance of a biomechanical staple during bone (tibia) growth arrest. The staples considered in this study were made of 1.4441 stainless steel, the model of tibia consisted of two materials representing corticalis and spongiosis. Hooke's law was used for modeling materials' behaviors for finite element analysis (FEA). The maxima of stress and total staple displacement were evaluated using the finite element method and verification of the results, along with the determination of the maximum loading (growing) force that the staples are capable of withstanding, was performed experimentally. The presented method can be used to determine the safety and usability of staples for bone growth arrest. According to our results, the design of Blount staples considered in this paper is safe and suitable for orthopedic treatment.

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Biomechanical analysis of staples for epiphysiodesis

Author: Frydrýšek, Karel
Publisher: MDPI
Year: 2022
DOI: 10.3390/app12020614
Source: https://dspace.vsb.cz/bitstreams/651c06d7-8392-4240-b2e0-2db040e56b7b/download
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Ci a ion: F yd ýšek, K.; ˇ
Cepica, D.;
Halo, T.; Skoupý, O.; Ple a, L.;
Madeja, R.; Pome lo á, J.; Lose o á,
M.; Kou ecký, J.; Michal, P.; e al.
Biomechanical Analysis o S aples o
Epiphysiodesis. Appl. Sci. 2022,12,
614. h ps://doi.o g/10.3390/
app12020614
Academic Edi o : Claudio Bel ede e
Recei ed: 9 Decembe 2021
Accep ed: 6 Janua y 2022
Published: 9 Janua y 2022
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Licensee MDPI, Basel, Swi ze land.
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A ibu ion (CC BY) license (h ps://
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4.0/).
applied
sciences
A icle
Biomechanical Analysis o S aples o Epiphysiodesis
Ka el F yd ýšek 1,2,* , Daniel ˇ
Cepica 1,2, Tomáš Halo 1,2 , Ondˇ ej Skoupý1,2, Leopold Ple a 1,3,
Roman Madeja 1,3, Jana Pome lo á1,3 , Monika Lose o á4,5 , Jan Kou ecký5, Pa el Michal 5, Voj ˇech Ha las 6,
Šimon K aus 6,7, Dominik ˇ
Du ica 7, Ka eˇ ina Pe e ek Dˇedko á8, Ma ek Pagáˇc 9, Pa el K pec 10 and
Paweł Osemlak 11
1Ins i u e o Eme gency Medicine, Facul y o Medicine, Uni e si y o Os a a, Syllabo a 19,
703 00 Os a a-Ví ko ice, Czech Republic; [email p o ec ed] (D. ˇ
C.); [email p o ec ed] (T.H.);
[email p o ec ed] (O.S.); [email p o ec ed] (L.P.); [email p o ec ed] (R.M.);
[email p o ec ed] (J.P.)
2
Depa men o Applied Mechanics, Facul y o Mechanical Enginee ing, VSB—Technical Uni e si y o Os a a,
17. Lis opadu 2172/15, 708 00 Os a a, Czech Republic
3T auma Cen e , 17., Uni e si y Hospi al Os a a, Lis opadu 1790, 708 52 Os a a-Po uba, Czech Republic
4Facul y o Ma e ials Science and Technology, VSB—Technical Uni e si y o Os a a, 17. Lis opadu 2172/15,
708 00 Os a a, Czech Republic; [email p o ec ed]
5Medin, a.s, Vlacho icka 619, 592 31 No éMˇes o na Mo a ˇe, Czech Republic; [email p o ec ed] (J.K.);
[email p o ec ed] (P.M.)
6Mo ol Uni e si y Hospi al, V Ú alu 84, 150 06 P ague 5, Czech Republic;
[email p o ec ed] (V.H.); [email p o ec ed] (Š.K.)
7Depa men o O hopaedics, Second Facul y o Medicine, Cha les Uni e si y, V Ú alu 84,
150 06 P ague 5, Czech Republic; [email p o ec ed]
8
Cen e o Ad anced Inno a ion Technologies, VSB—Technical Uni e si y o Os a a, 17. Lis opadu 15/2172,
708 00 Os a a-Po uba, Czech Republic; ka e ina.pe e [email p o ec ed]
9Depa men o Machining, Facul y o Mechanical Enginee ing, VSB—Technical Uni e si y o Os a a,
Assembly and Enginee ing Me ology, 17. Lis opadu 2172/15, 708 00 Os a a, Czech Republic;
[email p o ec ed]
10 V-NASS, a.s., Halaso a 2938/1a, 703 00 Os a a-Ví ko ice, Czech Republic; [email p o ec ed]
11 Pedia ic Uni e si y Hospi al Named by P o . An oni G˛ebala in Lublin, ul. P o . A. G˛ebali 6,
Depa men o Pedia ic Su ge y and T auma ology, Medical Uni e si y o Lublin, 20-093 Lublin, Poland;
[email p o ec ed]
*Co espondence: ka [email p o ec ed]; Tel.: +420-597323495; Fax: +420-596916490
Abs ac :
Limb asymme y can, and o en does, cause a ious heal h p oblems. Bloun bone s aples
(clips) a e used o co ec such une en g ow h. This a icle analyzes he pe o mance o a biome-
chanical s aple du ing bone ( ibia) g ow h a es . The s aples conside ed in his s udy we e made o
1.4441 s ainless s eel, he model o ibia consis ed o wo ma e ials ep esen ing co icalis and spongio-
sis. Hooke’s law was used o modeling ma e ials’ beha io s o ini e elemen analysis (FEA). The
maxima o s ess and o al s aple displacemen we e e alua ed using he ini e elemen me hod and
e i ica ion o he esul s, along wi h he de e mina ion o he maximum loading (g owing) o ce ha
he s aples a e capable o wi hs anding, was pe o med expe imen ally. The p esen ed me hod can be
used o de e mine he sa e y and usabili y o s aples o bone g ow h a es . Acco ding o ou esul s,
he design o Bloun s aples conside ed in his pape is sa e and sui able o o hopedic ea men .
Keywo ds: biomechanics; o hopedics; Bloun s aple; FEA; expe imen ; epiphysiodesis
1. In oduc ion
The g ow h de o mi ies, one o which is Bloun ’s disease, a e globally among he mos
common condi ions o p esen in pedia ic o hopedic clinics [
1
,
2
]. These de o mi ies can,
al hough a ely, be associa ed also wi h childhood obesi y, i.e., high body mass index (BMI);
o u he in o ma ion, see [3].
Appl. Sci. 2022,12, 614. h ps://doi.o g/10.3390/app12020614 h ps://www.mdpi.com/jou nal/applsci
Appl. Sci. 2022,12, 614 2 o 16
These g ow h de o mi ies ha e been, o many yea s, ea ed su gically, u ilizing he
manipula ion o na u al g ow h capabili ies o he bone; see [
1
]. Epiphyseal s apling is
one o he mos commonly and adi ionally used me hods o such co ec ion, using ine
me al s aples (clips) implan ed in o a speci ic pa o a child’s long bone o empo a ily
p e en i s g ow h. Hence, epiphyseal s apling (also known as epiphysiodesis, Bloun
epiphysiodesis, bone g ow h es ic ion, o bone g ow h su ge y) in ol es placing such
s aples in a way o b idge he g ow h pla e o slow down he g ow h o he long bone;
see [1,4]. This sho su gical p ocedu e is pe o med unde gene al anes hesia.
The e a e no compa able nonsu gical al e na i es o epiphyseal s apling. Su gical
al e na i es include leg sho ening (i.e., a su ge y du ing which a sec ion o he bone is cu
ou and agmen s a e joined oge he wi h a pla e), pe cu aneous epiphysiodesis, see [
5
],
open epiphysiodesis, and, ecen ly, ension band echnique.
Epiphyseal s apling was in oduced by Wal e Bloun in 1949, see [
6
], and since hen,
i has become a common p ocedu e o co ec ing, in pa icula , angula de o mi ies o he
knee (genu a um o genu algum) in child en. The g ow h o he child’s o adolescen ’s
bone is associa ed mainly wi h physis, i.e., a ca ilage s uc u e nea join s; see [
1
,
4
]. Bloun
s aples a e also used o pseudoa h osis ea men [7].
Using s aples, he physis (epiphyseal pla e) can be ela i ely simply es ained ei-
he on bo h sides when co ec ing limb leng h disc epancy (i.e., “epiphysiodesis”) o
only on one side when co ec ing angula de o mi ies (i.e., “hemiepiphyseodesis”) (see
Figu es 1and 2
). Unlike he i e e sible me hod o pe manen epiphysiodesis, see [
8
], epi-
physeal s apling does no des oy he epiphyseal pla e and, he e o e, allows esump ion o
he g ow h once he op imal co ec ion is achie ed; see [4].
Appl. Sci. 2022, 12, x FOR PEER REVIEW 2 o 16
These g ow h de o mi ies ha e been, o many yea s, ea ed su gically, u ilizing he
manipula ion o na u al g ow h capabili ies o he bone; see [1]. Epiphyseal s apling is one
o he mos commonly and adi ionally used me hods o such co ec ion, using ine
me al s aples (clips) implan ed in o a speci ic pa o a child’s long bone o empo a ily
p e en i s g ow h. Hence, epiphyseal s apling (also known as epiphysiodesis, Bloun
epiphysiodesis, bone g ow h es ic ion, o bone g ow h su ge y) in ol es placing such
s aples in a way o b idge he g ow h pla e o slow down he g ow h o he long bone; see
[1,4]. This sho su gical p ocedu e is pe o med unde gene al anes hesia.
The e a e no compa able nonsu gical al e na i es o epiphyseal s apling. Su gical al-
e na i es include leg sho ening (i.e., a su ge y du ing which a sec ion o he bone is cu
ou and agmen s a e joined oge he wi h a pla e), pe cu aneous epiphysiodesis, see [5],
open epiphysiodesis, and, ecen ly, ension band echnique.
Epiphyseal s apling was in oduced by Wal e Bloun in 1949, see [6], and since hen,
i has become a common p ocedu e o co ec ing, in pa icula , angula de o mi ies o he
knee (genu a um o genu algum) in child en. The g ow h o he child’s o adolescen ’s
bone is associa ed mainly wi h physis, i.e., a ca ilage s uc u e nea join s; see [1,4]. Bloun
s aples a e also used o pseudoa h osis ea men [7].
Using s aples, he physis (epiphyseal pla e) can be ela i ely simply es ained ei he
on bo h sides when co ec ing limb leng h disc epancy (i.e., “epiphysiodesis”) o only on
one side when co ec ing angula de o mi ies (i.e., “hemiepiphyseodesis”) (see Figu es 1
and 2). Unlike he i e e sible me hod o pe manen epiphysiodesis, see [8], epiphyseal
s apling does no des oy he epiphyseal pla e and, he e o e, allows esump ion o he
g ow h once he op imal co ec ion is achie ed; see [4].
Figu e 1. Pa s o he g owing bone ( ibia).
Figu e 1. Pa s o he g owing bone ( ibia).
Recen ly, he ension band echnique, in oduced by S e ens in 2007 [
9
], using non-
locking pla es (simila o hose used o os eosyn hesis) and sc ews almos in he same
posi ion as s aples, has g adually become a p e e able al e na i e o s apling. Howe e ,
Bloun ’s o iginal me hod s ill emains an e ec i e means o he ea men o lowe limb
de o mi ies in adolescen s; see [1,4,10].
Acco ding o [
1
,
4
], besides accu a e diagnosis con i med by a adiog am o he whole
limb (see Figu e 2), good iming o he ea men is also e y impo an . The su gical
p ocedu e in ol es a sho longi udinal incision h ough so issues o e he physis and
ex ape ios eal implan a ion o he s aple using a special ins umen unde adiog aphy
con ol [
11
] (see Figu e 3). The s aple mus b idge he physis bu no pene a e i o p e en
i s impai men (see Figu e 4).
The s aples should no be es ic ing he physis o longe han 2 yea s o p e en
pe manen g ow h cessa ion [
12
]. O he complica ions du ing ea men , such as damaging
he physis by imp ecise s aple implan a ion, mechanical ailu e o he s aple (bending, a ely
b eak), o s aple mig a ion can occu . The las one is also he mos common complica ion
and disad an age compa ed wi h he ension band echnique; see [1,4].
Appl. Sci. 2022,12, 614 3 o 16
Appl. Sci. 2022, 12, x FOR PEER REVIEW 2 o 16
These g ow h de o mi ies ha e been, o many yea s, ea ed su gically, u ilizing he
manipula ion o na u al g ow h capabili ies o he bone; see [1]. Epiphyseal s apling is one
o he mos commonly and adi ionally used me hods o such co ec ion, using ine
me al s aples (clips) implan ed in o a speci ic pa o a child’s long bone o empo a ily
p e en i s g ow h. Hence, epiphyseal s apling (also known as epiphysiodesis, Bloun
epiphysiodesis, bone g ow h es ic ion, o bone g ow h su ge y) in ol es placing such
s aples in a way o b idge he g ow h pla e o slow down he g ow h o he long bone; see
[1,4]. This sho su gical p ocedu e is pe o med unde gene al anes hesia.
The e a e no compa able nonsu gical al e na i es o epiphyseal s apling. Su gical al-
e na i es include leg sho ening (i.e., a su ge y du ing which a sec ion o he bone is cu
ou and agmen s a e joined oge he wi h a pla e), pe cu aneous epiphysiodesis, see [5],
open epiphysiodesis, and, ecen ly, ension band echnique.
Epiphyseal s apling was in oduced by Wal e Bloun in 1949, see [6], and since hen,
i has become a common p ocedu e o co ec ing, in pa icula , angula de o mi ies o he
knee (genu a um o genu algum) in child en. The g ow h o he child’s o adolescen ’s
bone is associa ed mainly wi h physis, i.e., a ca ilage s uc u e nea join s; see [1,4]. Bloun
s aples a e also used o pseudoa h osis ea men [7].
Using s aples, he physis (epiphyseal pla e) can be ela i ely simply es ained ei he
on bo h sides when co ec ing limb leng h disc epancy (i.e., “epiphysiodesis”) o only on
one side when co ec ing angula de o mi ies (i.e., “hemiepiphyseodesis”) (see Figu es 1
and 2). Unlike he i e e sible me hod o pe manen epiphysiodesis, see [8], epiphyseal
s apling does no des oy he epiphyseal pla e and, he e o e, allows esump ion o he
g ow h once he op imal co ec ion is achie ed; see [4].
Figu e 1. Pa s o he g owing bone ( ibia).
Figu e 2.
(
a
) Long adiog am o p eope a i e genu algum and (
b
) consecu i e co ec ion wi h s aples
in emu ; see [4].
Appl. Sci. 2022, 12, x FOR PEER REVIEW 3 o 16
Figu e 2. (a) Long adiog am o p eope a i e genu algum and (b) consecu i e co ec ion wi h s a-
ples in emu ; see [4].
Recen ly, he ension band echnique, in oduced by S e ens in 2007 [9], using non-
locking pla es (simila o hose used o os eosyn hesis) and sc ews almos in he same
posi ion as s aples, has g adually become a p e e able al e na i e o s apling. Howe e ,
Bloun ’s o iginal me hod s ill emains an e ec i e means o he ea men o lowe limb
de o mi ies in adolescen s; see [1,4,10].
Acco ding o [1,4], besides accu a e diagnosis con i med by a adiog am o he whole
limb (see Figu e 2), good iming o he ea men is also e y impo an . The su gical p o-
cedu e in ol es a sho longi udinal incision h ough so issues o e he physis and ex-
ape ios eal implan a ion o he s aple using a special ins umen unde adiog aphy con-
ol [11] (see Figu e 3). The s aple mus b idge he physis bu no pene a e i o p e en
i s impai men (see Figu e 4).
Figu e 3. Implan a ion o s aples.
Figu e 4. Posi ion o s aples b idging he physis in emu .
The s aples should no be es ic ing he physis o longe han 2 yea s o p e en
pe manen g ow h cessa ion [12]. O he complica ions du ing ea men , such as damag-
ing he physis by imp ecise s aple implan a ion, mechanical ailu e o he s aple (bending,
a ely b eak), o s aple mig a ion can occu . The las one is also he mos common com-
plica ion and disad an age compa ed wi h he ension band echnique; see [1,4].
The e is a lack o in o ma ion ega ding he biomechanical aspec o Bloun ’s s aples;
hence, one o he goals o ou publishing is o ill he gap in his ield.
The e a e wo main me hods o sol ing biomechanical p oblems:
• Nume ical app oach—( he main subjec o his pape ).
• Expe imen al app oach (used and desc ibed only ma ginally he e).
In his pape , he s ess and de o ma ion o s aples du ing epiphysiodesis a e e alu-
a ed by a nume ical app oach using ini e elemen analysis (FEA). The ini e elemen
me hod (FEM) is a ecognized ins umen o nume ical analysis widely used in
Figu e 3. Implan a ion o s aples.
Appl. Sci. 2022, 12, x FOR PEER REVIEW 3 o 16
Figu e 2. (a) Long adiog am o p eope a i e genu algum and (b) consecu i e co ec ion wi h s a-
ples in emu ; see [4].
Recen ly, he ension band echnique, in oduced by S e ens in 2007 [9], using non-
locking pla es (simila o hose used o os eosyn hesis) and sc ews almos in he same
posi ion as s aples, has g adually become a p e e able al e na i e o s apling. Howe e ,
Bloun ’s o iginal me hod s ill emains an e ec i e means o he ea men o lowe limb
de o mi ies in adolescen s; see [1,4,10].
Acco ding o [1,4], besides accu a e diagnosis con i med by a adiog am o he whole
limb (see Figu e 2), good iming o he ea men is also e y impo an . The su gical p o-
cedu e in ol es a sho longi udinal incision h ough so issues o e he physis and ex-
ape ios eal implan a ion o he s aple using a special ins umen unde adiog aphy con-
ol [11] (see Figu e 3). The s aple mus b idge he physis bu no pene a e i o p e en
i s impai men (see Figu e 4).
Figu e 3. Implan a ion o s aples.
Figu e 4. Posi ion o s aples b idging he physis in emu .
The s aples should no be es ic ing he physis o longe han 2 yea s o p e en
pe manen g ow h cessa ion [12]. O he complica ions du ing ea men , such as damag-
ing he physis by imp ecise s aple implan a ion, mechanical ailu e o he s aple (bending,
a ely b eak), o s aple mig a ion can occu . The las one is also he mos common com-
plica ion and disad an age compa ed wi h he ension band echnique; see [1,4].
The e is a lack o in o ma ion ega ding he biomechanical aspec o Bloun ’s s aples;
hence, one o he goals o ou publishing is o ill he gap in his ield.
The e a e wo main me hods o sol ing biomechanical p oblems:
• Nume ical app oach—( he main subjec o his pape ).
• Expe imen al app oach (used and desc ibed only ma ginally he e).
In his pape , he s ess and de o ma ion o s aples du ing epiphysiodesis a e e alu-
a ed by a nume ical app oach using ini e elemen analysis (FEA). The ini e elemen
me hod (FEM) is a ecognized ins umen o nume ical analysis widely used in
Figu e 4. Posi ion o s aples b idging he physis in emu .
The e is a lack o in o ma ion ega ding he biomechanical aspec o Bloun ’s s aples;
hence, one o he goals o ou publishing is o ill he gap in his ield.
The e a e wo main me hods o sol ing biomechanical p oblems:
•Nume ical app oach—( he main subjec o his pape ).
•Expe imen al app oach (used and desc ibed only ma ginally he e).
In his pape , he s ess and de o ma ion o s aples du ing epiphysiodesis a e e al-
ua ed by a nume ical app oach using ini e elemen analysis (FEA). The ini e elemen
me hod (FEM) is a ecognized ins umen o nume ical analysis widely used in enginee -
Appl. Sci. 2022,12, 614 4 o 16
ing mechanics (see, e.g., [
13
]) and biomechanics. I has been p e iously used o a ious
biomechanical asks [14–16], including Bloun s aple applica ions in epiphysiodesis [17].
To e i y he esul s o he nume ical solu ion, i.e., o assess he usabili y o s aples
unde he chosen loading (g owing) o ce, and o ind he maximum loading (g owing)
o ce ha he s aples can wi hs and, a simple expe imen al app oach was also used in his
pape . Expe imen s can be used in combina ion wi h FEA (as we do he e o , e.g., in [
18
]), o
expe imen s can se e as a s andalone ool o simula ion o eali y, see, e.g., [19].
Ou app oach can be u he used o ano he ypes o modi ica ions o Bloun ’s
s aples, pla es, and simila implan a es.
2. Ma e ials and Me hods
The bone g ow h occu s in he epiphyseal pla e, whe e a new bone mass is c ea ed.
Conside ing his ac , he simula ion o he g owing p ocess u ned ou o be di icul .
Fo his eason, we came up wi h a solu ion whe e he a i icial bone ( ibia) is cu in
wo a he posi ion o he epiphyseal pla e; u he mo e, we assume ha he bone g ows
p edominan ly in he di ec ion o he bone axis (i.e., only opposi ional g ow h is conside ed),
which means ha g ow h can be simula ed by pulling he wo bone segmen s away om
each o he .
Models o he s aples, bo h 3D CAD and physical, we e p o ided by MEDIN, a.s.; see
Figu e 5and [20].
Appl. Sci. 2022, 12, x FOR PEER REVIEW 4 o 16
enginee ing mechanics (see, e.g., [13]) and biomechanics. I has been p e iously used o
a ious biomechanical asks [14–16], including Bloun s aple applica ions in epiphysi-
odesis [17].
To e i y he esul s o he nume ical solu ion, i.e., o assess he usabili y o s aples
unde he chosen loading (g owing) o ce, and o ind he maximum loading (g owing)
o ce ha he s aples can wi hs and, a simple expe imen al app oach was also used in his
pape . Expe imen s can be used in combina ion wi h FEA (as we do he e o , e.g., in [18]),
o expe imen s can se e as a s andalone ool o simula ion o eali y, see, e.g., [19].
Ou app oach can be u he used o ano he ypes o modi ica ions o Bloun ’s s a-
ples, pla es, and simila implan a es.
2. Ma e ials and Me hods
The bone g ow h occu s in he epiphyseal pla e, whe e a new bone mass is c ea ed.
Conside ing his ac , he simula ion o he g owing p ocess u ned ou o be di icul . Fo
his eason, we came up wi h a solu ion whe e he a i icial bone ( ibia) is cu in wo a he
posi ion o he epiphyseal pla e; u he mo e, we assume ha he bone g ows p edomi-
nan ly in he di ec ion o he bone axis (i.e., only opposi ional g ow h is conside ed),
which means ha g ow h can be simula ed by pulling he wo bone segmen s away om
each o he .
Models o he s aples, bo h 3D CAD and physical, we e p o ided by MEDIN, a.s.; see
Figu e 5 and [20].
Figu e 5. Physical model and 3D CAD model wi h main dimensions (mm), supplied by MEDIN,
a.s.
2.1. Fini e Elemen Analysis
The nume ical analysis is pe o med using he Ansys Wo kbench 2020 R2 sw; see
[21]. Homogenous and iso opic ma e ial models a e assumed o be good app oxima ions
o eali y. S aples a e made o biocompa ible s ainless s eel 1.4441 (AISI 316L), see [4], and
he a i icial bone model consis s o co icalis and spongiosis (i.e., he co ical and spongy
pa s); mechanical p ope ies we e aken om [22], whe e Young’s modulus o spongiosis
was epo ed o ange be ween 0.1 and 0.5 GPa and o co icalis be ween 12 and 18 GPa.
F om his, alues close o he uppe limi we e chosen; his can, o example, illus a e
obesi y (i.e., s onge bones o accommoda e o highe body mass). Used ma e ial models
a e p esen ed in Table 1.
Table 1. Ma e ial models o bone and s ainless s eel.
Ma e ial
Young’s Modulus (GPa)
Poisson’s Ra io (1)
Yield S eng h
(MPa)
Ul ima e S eng h
(MPa)
1.4441
183
0.33
690
800
Co icalis
16.1
0.3
Spongiosis
0.4
0.3
Figu e 5.
Physical model and 3D CAD model wi h main dimensions (mm), supplied by MEDIN, a.s.
2.1. Fini e Elemen Analysis
The nume ical analysis is pe o med using he Ansys Wo kbench 2020 R2 sw; see [
21
].
Homogenous and iso opic ma e ial models a e assumed o be good app oxima ions o
eali y. S aples a e made o biocompa ible s ainless s eel 1.4441 (AISI 316L), see [
4
], and
he a i icial bone model consis s o co icalis and spongiosis (i.e., he co ical and spongy
pa s); mechanical p ope ies we e aken om [22], whe e Young’s modulus o spongiosis
was epo ed o ange be ween 0.1 and 0.5 GPa and o co icalis be ween 12 and 18 GPa.
F om his, alues close o he uppe limi we e chosen; his can, o example, illus a e
obesi y (i.e., s onge bones o accommoda e o highe body mass). Used ma e ial models
a e p esen ed in Table 1.
Table 1. Ma e ial models o bone and s ainless s eel.
Ma e ial Young’s
Modulus (GPa)
Poisson’s Ra io
(1)
Yield S eng h
(MPa)
Ul ima e
S eng h (MPa)
1.4441 183 0.33 690 800
Co icalis 16.1 0.3
Spongiosis 0.4 0.3
Appl. Sci. 2022,12, 614 5 o 16
Resea ch by Halo e al. [
4
] ocused on a simple bone ma e ial model, conside ing he
co ical pa as he only ma e ial o he bone. In he cu en pape , howe e , we imp o ed
he bone ma e ial model by di iding i in o co icalis and spongiosis pa s.
2.1.1. CAD and FEM Model
The used CAD model ob ained om a 3D scan and he bone model used in he
expe imen a e no 100% iden ical; ne e heless, hey a e su icien ly simila o allow
expe imen al e i ica ion o he calcula ion esul s; see Figu e 6. The model o he whole
bone is no necessa y o ou pu poses and, o his eason, only he p oximal pa o he
ibia was used in his calcula ion. This p oximal pa was hen “cu ” in wo a he si e o
he epiphyseal pla e. The s aples we e i ually placed in he bone in he way hey usually
a e du ing epiphysiodesis, i.e., in he gene al a ea b idging he physis.
Appl. Sci. 2022, 12, x FOR PEER REVIEW 5 o 16
Resea ch by Halo e al. [4] ocused on a simple bone ma e ial model, conside ing he
co ical pa as he only ma e ial o he bone. In he cu en pape , howe e , we imp o ed
he bone ma e ial model by di iding i in o co icalis and spongiosis pa s.
2.1.1. CAD and FEM Model
The used CAD model ob ained om a 3D scan and he bone model used in he ex-
pe imen a e no 100% iden ical; ne e heless, hey a e su icien ly simila o allow expe -
imen al e i ica ion o he calcula ion esul s; see Figu e 6. The model o he whole bone
is no necessa y o ou pu poses and, o his eason, only he p oximal pa o he ibia
was used in his calcula ion. This p oximal pa was hen “cu ” in wo a he si e o he
epiphyseal pla e. The s aples we e i ually placed in he bone in he way hey usually a e
du ing epiphysiodesis, i.e., in he gene al a ea b idging he physis.
Figu e 6. 3D CAD model o he bone and s aples wi h main dimensions (mm).
The CAD model o s aple p o ided by MEDIN a.s. con ains no ches, which a e no
sui able o FEA. Fo his eason, sha p edges we e ounded; see Figu e 7. Howe e , hese
sha p edges a e impo an o p ope ly inse ing he s aple in a bone.
Figu e 7. 3D CAD model o he s aple wi h ounded sha p edges (mm).
Figu e 6. 3D CAD model o he bone and s aples wi h main dimensions (mm).
The CAD model o s aple p o ided by MEDIN a.s. con ains no ches, which a e no
sui able o FEA. Fo his eason, sha p edges we e ounded; see Figu e 7. Howe e , hese
sha p edges a e impo an o p ope ly inse ing he s aple in a bone.
Appl. Sci. 2022, 12, x FOR PEER REVIEW 5 o 16
Resea ch by Halo e al. [4] ocused on a simple bone ma e ial model, conside ing he
co ical pa as he only ma e ial o he bone. In he cu en pape , howe e , we imp o ed
he bone ma e ial model by di iding i in o co icalis and spongiosis pa s.
2.1.1. CAD and FEM Model
The used CAD model ob ained om a 3D scan and he bone model used in he ex-
pe imen a e no 100% iden ical; ne e heless, hey a e su icien ly simila o allow expe -
imen al e i ica ion o he calcula ion esul s; see Figu e 6. The model o he whole bone
is no necessa y o ou pu poses and, o his eason, only he p oximal pa o he ibia
was used in his calcula ion. This p oximal pa was hen “cu ” in wo a he si e o he
epiphyseal pla e. The s aples we e i ually placed in he bone in he way hey usually a e
du ing epiphysiodesis, i.e., in he gene al a ea b idging he physis.
Figu e 6. 3D CAD model o he bone and s aples wi h main dimensions (mm).
The CAD model o s aple p o ided by MEDIN a.s. con ains no ches, which a e no
sui able o FEA. Fo his eason, sha p edges we e ounded; see Figu e 7. Howe e , hese
sha p edges a e impo an o p ope ly inse ing he s aple in a bone.
Figu e 7. 3D CAD model o he s aple wi h ounded sha p edges (mm).
Figu e 7. 3D CAD model o he s aple wi h ounded sha p edges (mm).

Appl. Sci. 2022,12, 614 6 o 16
The adius size o 0.25 mm, acco ding o Figu e 7, is qui e small, because his pa o
he s aple is ela i ely hin, and using bigge adius size (e.g., 0.5 mm) would esul in nea
comple e emo al o his pa .
In his pape , we used only he bone model and s aples o FEA. The eason o his
accep able simpli ica ion lies in he ac ha he limb g ow h is p ima ily de e mined by
he bone (o , mo e accu a ely, epiphyseal pla e). The bone is in ac (i.e., wi hou ac u e);
he e o e, he in luence o he muscles, ligamen s, menisci, and syno ia on bone g ow h is
negligible compa ed o he load on he bone.
Muscles, ligamen s, menisci, and syno ia could play a small ole in es ic ing he
s aple mig a ion, bu his e ec is no no iceable in ou s udy and hence is conside ed
negligible. Thus, muscle and o he issues and luids we e omi ed in his pape .
The in luence o ana omical pa s in ca i as a icula is (i.e., men ioned muscles, lig-
amen s, menisci, and syno ia) migh play signi ican ole in ambula ion o pa ien s wi h
Bloun s aples, see [23].
The ans o ma ion o he CAD model in o he FEM model is p esen ed in Figu e 8.
Conside ing he complexi y o he bone shape, he ibia was disc e ized by e ahed al
elemen s (SOLID187 in Ansys sw) wi h a global maximum size o 2.5 mm. The elemen size
in holes o s aples was locally e ined o mi o he elemen size o he s aples. In addi ion,
a e inemen o 0.5 mm was pe o med in a small ci cula a ea in he immedia e icini y
o holes o s aples. The global elemen size is ela i ely la ge as we a e ocusing on and
e alua ing only he s aple esponse, no ha o he bone. The co icalis and spongiosis FE
meshes a e con inuously connec ed by nodes and elemen s sha ing aces (i.e., con o mal
mesh achie ed by sha ed opology unc ion in Ansys SpaceClaim sw), see [21].
Appl. Sci. 2022, 12, x FOR PEER REVIEW 6 o 16
The adius size o 0.25 mm, acco ding o Figu e 7, is qui e small, because his pa o
he s aple is ela i ely hin, and using bigge adius size (e.g., 0.5 mm) would esul in
nea comple e emo al o his pa .
In his pape , we used only he bone model and s aples o FEA. The eason o his
accep able simpli ica ion lies in he ac ha he limb g ow h is p ima ily de e mined by
he bone (o , mo e accu a ely, epiphyseal pla e). The bone is in ac (i.e., wi hou ac u e);
he e o e, he in luence o he muscles, ligamen s, menisci, and syno ia on bone g ow h
is negligible compa ed o he load on he bone.
Muscles, ligamen s, menisci, and syno ia could play a small ole in es ic ing he
s aple mig a ion, bu his e ec is no no iceable in ou s udy and hence is conside ed
negligible. Thus, muscle and o he issues and luids we e omi ed in his pape .
The in luence o ana omical pa s in ca i as a icula is (i.e., men ioned muscles, liga-
men s, menisci, and syno ia) migh play signi ican ole in ambula ion o pa ien s wi h
Bloun s aples, see [23].
The ans o ma ion o he CAD model in o he FEM model is p esen ed in Figu e 8.
Conside ing he complexi y o he bone shape, he ibia was disc e ized by e ahed al
elemen s (SOLID187 in Ansys sw) wi h a global maximum size o 2.5 mm. The elemen
size in holes o s aples was locally e ined o mi o he elemen size o he s aples. In
addi ion, a e inemen o 0.5 mm was pe o med in a small ci cula a ea in he immedia e
icini y o holes o s aples. The global elemen size is ela i ely la ge as we a e ocusing
on and e alua ing only he s aple esponse, no ha o he bone. The co icalis and spongi-
osis FE meshes a e con inuously connec ed by nodes and elemen s sha ing aces (i.e., con-
o mal mesh achie ed by sha ed opology unc ion in Ansys SpaceClaim sw), see [21].
Figu e 8. FEM model o he bone and s aples.
S aples we e disc e ized by a hex-dominan mesh (SOLID186 + some SOLID187 ele-
men s) wi h a global maximum elemen size o 0.5 mm. The elemen size was locally e-
ined on adii and in he immedia e icini y o hese a eas; see Figu e 9.
Figu e 8. FEM model o he bone and s aples.
S aples we e disc e ized by a hex-dominan mesh (SOLID186 + some SOLID187
elemen s) wi h a global maximum elemen size o 0.5 mm. The elemen size was locally
e ined on adii and in he immedia e icini y o hese a eas; see Figu e 9.
The p esen ed mesh in i s inal o m was used o he inal calcula ion and esul
e alua ion. The sensi i i y analysis s a ed wi h a coa se mesh, and a e each compu a ion,
a new, e ined, mesh wi h hal he elemen size o he p e ious mesh was c ea ed. This
p ocess was epea ed un il esul s o wo di e en meshes we e close (wi hin a 1% ma gin
o e o ); in his way, he mesh sensi i i y analysis was pe o med.
Addi ional in o ma ion abou FE mesh ega ding he numbe o elemen s and nodes
is p esen ed in Table 2.
Appl. Sci. 2022,12, 614 7 o 16
Appl. Sci. 2022, 12, x FOR PEER REVIEW 6 o 16
The adius size o 0.25 mm, acco ding o Figu e 7, is qui e small, because his pa o
he s aple is ela i ely hin, and using bigge adius size (e.g., 0.5 mm) would esul in
nea comple e emo al o his pa .
In his pape , we used only he bone model and s aples o FEA. The eason o his
accep able simpli ica ion lies in he ac ha he limb g ow h is p ima ily de e mined by
he bone (o , mo e accu a ely, epiphyseal pla e). The bone is in ac (i.e., wi hou ac u e);
he e o e, he in luence o he muscles, ligamen s, menisci, and syno ia on bone g ow h
is negligible compa ed o he load on he bone.
Muscles, ligamen s, menisci, and syno ia could play a small ole in es ic ing he
s aple mig a ion, bu his e ec is no no iceable in ou s udy and hence is conside ed
negligible. Thus, muscle and o he issues and luids we e omi ed in his pape .
The in luence o ana omical pa s in ca i as a icula is (i.e., men ioned muscles, liga-
men s, menisci, and syno ia) migh play signi ican ole in ambula ion o pa ien s wi h
Bloun s aples, see [23].
The ans o ma ion o he CAD model in o he FEM model is p esen ed in Figu e 8.
Conside ing he complexi y o he bone shape, he ibia was disc e ized by e ahed al
elemen s (SOLID187 in Ansys sw) wi h a global maximum size o 2.5 mm. The elemen
size in holes o s aples was locally e ined o mi o he elemen size o he s aples. In
addi ion, a e inemen o 0.5 mm was pe o med in a small ci cula a ea in he immedia e
icini y o holes o s aples. The global elemen size is ela i ely la ge as we a e ocusing
on and e alua ing only he s aple esponse, no ha o he bone. The co icalis and spongi-
osis FE meshes a e con inuously connec ed by nodes and elemen s sha ing aces (i.e., con-
o mal mesh achie ed by sha ed opology unc ion in Ansys SpaceClaim sw), see [21].
Figu e 8. FEM model o he bone and s aples.
S aples we e disc e ized by a hex-dominan mesh (SOLID186 + some SOLID187 ele-
men s) wi h a global maximum elemen size o 0.5 mm. The elemen size was locally e-
ined on adii and in he immedia e icini y o hese a eas; see Figu e 9.
Figu e 9.
Re ined FE mesh: (
a
) De ail o he mesh in/a ound he hole o he s aple; (
b
) Mesh o he
s aple; (c) Elemen size on s aple (mm).
Table 2. Numbe o FE elemen s and nodes.
Pa Numbe o FE
Elemen s
Numbe o FE
Nodes
Tibia Epiphysis 66,083 102,706
Me aphysis-Diaphysis 80,183 126,033
S aple Medial 132,292 438,008
La e al 132,581 442,394
To al 411,139 1,109,141
2.1.2. Bounda y Condi ions
The global coo dina e sys em was o ien ed so ha he Z-axis is pa allel o he bone
axis. As men ioned abo e, we assumed ha he bone g ows p edominan ly in he di ec ion
o he bone axis (i.e., opposi ional g ow h) and, he e o e, he alignmen o he axes allows
simple loading o he bone segmen s in he epiphyseal pla e in he Zdi ec ion. We assumed
ha o he g ow h o occu , he loading o ce Fz needs o ma ch he weigh o he pe son.
As he bone g ow h happens in he ea ly s ages o li e (childhood, adolescence), we ha e
chosen ou bone o come om an adolescen s anding on one leg wi h a chosen 100 kg
body weigh equi alen o Fz = 980.7 N. In [
24
], he g owing o ce was de e mined o be
app oxima ely 500 N, i.e., ou o ce Fz was o e es ima ed o e on he side o sa e y. The
o ce bounda y condi ion is illus a ed in Figu e 10.
The dis al end o he cu ibia is ully ixed (i.e., p esc ibed displacemen s a e u
x
= u
y
= u
z
= 0); in he p oximal pa ; he e is a pa ial ixa ion (i.e., p esc ibed displacemen s u
x
=
u
y
= 0) allowing o a mo emen in he Z di ec ion. De o ma ion bounda y condi ions a e
shown in Figu e 11.
Apa om he o ce and de o ma ion bounda y condi ions, ic ional con ac s be ween
he s aples and he bone mus be conside ed. The Coulomb ic ion coe icien be ween
s ainless s eel and bone anges om app oxima ely 0.25 o 0.7, acco ding o [
25
]. The
ic ion coe icien is highly dependen , among o he hings, on he su ace quali y o bo h
bone and s eel, ha dness o bone, e c. In his analysis, he ic ion coe icien was se o 0.2
(es ima ed by an educa ed guess), gi ing he possibili y o s aples o mig a e ou o bone.
The ic ion coe icien used in his s udy is lowe han in [
25
], aking in o accoun he body
luids and issues educing he ic ion. Ne e heless, e en wi h he low ic ion coe icien
used in ou s udy, he displacemen in con ac a eas was e y small, so ic ion does no
ha e a majo e ec on s ess dis ibu ion.
Appl. Sci. 2022,12, 614 8 o 16
Appl. Sci. 2022, 12, x FOR PEER REVIEW 7 o 16
Figu e 9. Re ined FE mesh: (a) De ail o he mesh in/a ound he hole o he s aple; (b) Mesh o he
s aple; (c) Elemen size on s aple (mm).
The p esen ed mesh in i s inal o m was used o he inal calcula ion and esul
e alua ion. The sensi i i y analysis s a ed wi h a coa se mesh, and a e each compu a-
ion, a new, e ined, mesh wi h hal he elemen size o he p e ious mesh was c ea ed.
This p ocess was epea ed un il esul s o wo di e en meshes we e close (wi hin a 1%
ma gin o e o ); in his way, he mesh sensi i i y analysis was pe o med.
Addi ional in o ma ion abou FE mesh ega ding he numbe o elemen s and nodes
is p esen ed in Table 2.
Table 2. Numbe o FE elemen s and nodes.
Pa
Numbe o FE Elemen s
Numbe o FE Nodes
Tibia
Epiphysis
66083
102706
Me aphysis-Diaphysis
80183
126033
S aple
Medial
132292
438008
La e al
132581
442394
To al
411139
1109141
2.1.2. Bounda y Condi ions
The global coo dina e sys em was o ien ed so ha he Z-axis is pa allel o he bone
axis. As men ioned abo e, we assumed ha he bone g ows p edominan ly in he di ec-
ion o he bone axis (i.e., opposi ional g ow h) and, he e o e, he alignmen o he axes
allows simple loading o he bone segmen s in he epiphyseal pla e in he Z di ec ion. We
assumed ha o he g ow h o occu , he loading o ce Fz needs o ma ch he weigh o
he pe son. As he bone g ow h happens in he ea ly s ages o li e (childhood, adoles-
cence), we ha e chosen ou bone o come om an adolescen s anding on one leg wi h a
chosen 100 kg body weigh equi alen o Fz = 980.7 N. In [24], he g owing o ce was
de e mined o be app oxima ely 500 N, i.e., ou o ce Fz was o e es ima ed o e on he
side o sa e y. The o ce bounda y condi ion is illus a ed in Figu e 10.
Figu e 10.
Fo ce bounda y condi ion— o ces Fz (equi alen o 100 kg) ac ing on he epiphyseal pla e.
Appl. Sci. 2022, 12, x FOR PEER REVIEW 8 o 16
Figu e 10. Fo ce bounda y condi ion— o ces Fz (equi alen o 100 kg) ac ing on he epiphyseal
pla e.
The dis al end o he cu ibia is ully ixed (i.e., p esc ibed displacemen s a e ux = uy
= uz = 0); in he p oximal pa ; he e is a pa ial ixa ion (i.e., p esc ibed displacemen s ux
= uy = 0) allowing o a mo emen in he Z di ec ion. De o ma ion bounda y condi ions
a e shown in Figu e 11.
Figu e 11. De o ma ion bounda y condi ions.
Apa om he o ce and de o ma ion bounda y condi ions, ic ional con ac s be-
ween he s aples and he bone mus be conside ed. The Coulomb ic ion coe icien be-
ween s ainless s eel and bone anges om app oxima ely 0.25 o 0.7, acco ding o [25].
The ic ion coe icien is highly dependen , among o he hings, on he su ace quali y o
bo h bone and s eel, ha dness o bone, e c. In his analysis, he ic ion coe icien was se
o 0.2 (es ima ed by an educa ed guess), gi ing he possibili y o s aples o mig a e ou o
bone. The ic ion coe icien used in his s udy is lowe han in [25], aking in o accoun
he body luids and issues educing he ic ion. Ne e heless, e en wi h he low ic ion
coe icien used in ou s udy, he displacemen in con ac a eas was e y small, so ic ion
does no ha e a majo e ec on s ess dis ibu ion.
2.2. Expe imen
The expe imen was conduc ed o suppo he FEA and clinical applica ions, i.e., o
de e mine he maximum loading o ce Fz o he bone ha he s aples can wi hs and and
o pa ially con i m he indings o he nume ical analysis. Howe e , as he expe imen s
a e no he main goal o his a icle ( he main goal is FEA), hey we e pe o med only once
on an ana omical a i icial bone [26] and once using ce i ied bone oam blocks [27] and
will be only b ie ly desc ibed (see Sec ion 4: Resul s o he Expe imen ).
One o he men ioned expe imen s was pe o med on a i icial bones o he SAW-
BONES b and. The bones a e made o composi e ma e ial mimicking he p ope ies o a
eal human bone, i.e., hey a e sui able o expe imen al pu poses. Fo he use o compo-
si e bone models in expe imen al es ing, see, e.g., [28,29].
The expe imen was based on he same p inciples and assump ions as hose used in
he p esen ed FEA. The ull body o he a i icial ibia was cu o ob ain only he p oximal
pa , which was subsequen ly spli in o wo segmen s a he si e o he epiphyseal pla e.
Bo h bone segmen s we e mechanically adjus ed o allow o he use o a jig. The jig con-
sis ed o a sc ew wi h a washe and nu a ached o he uppe bone segmen (epiphysis)
and o a sel - apping sc ew holding he lowe bone segmen (me aphysis-diaphysis). S a-
ples we e inse ed in o he bone segmen s (in a simila loca ion as in FEA), b idging he
epiphyseal pla e. Bone segmen s we e hen pulled away om each o he using he jig.
Figu e 11. De o ma ion bounda y condi ions.
2.2. Expe imen
The expe imen was conduc ed o suppo he FEA and clinical applica ions, i.e., o
de e mine he maximum loading o ce Fz o he bone ha he s aples can wi hs and and o
pa ially con i m he indings o he nume ical analysis. Howe e , as he expe imen s a e
no he main goal o his a icle ( he main goal is FEA), hey we e pe o med only once on
an ana omical a i icial bone [
26
] and once using ce i ied bone oam blocks [
27
] and will
be only b ie ly desc ibed (see Sec ion 4: Resul s o he Expe imen ).
One o he men ioned expe imen s was pe o med on a i icial bones o he SAW-
BONES b and. The bones a e made o composi e ma e ial mimicking he p ope ies o a
eal human bone, i.e., hey a e sui able o expe imen al pu poses. Fo he use o composi e
bone models in expe imen al es ing, see, e.g., [28,29].
Appl. Sci. 2022,12, 614 9 o 16
The expe imen was based on he same p inciples and assump ions as hose used in he
p esen ed FEA. The ull body o he a i icial ibia was cu o ob ain only he p oximal pa ,
which was subsequen ly spli in o wo segmen s a he si e o he epiphyseal pla e. Bo h
bone segmen s we e mechanically adjus ed o allow o he use o a jig. The jig consis ed o
a sc ew wi h a washe and nu a ached o he uppe bone segmen (epiphysis) and o a
sel - apping sc ew holding he lowe bone segmen (me aphysis-diaphysis). S aples we e
inse ed in o he bone segmen s (in a simila loca ion as in FEA), b idging he epiphyseal
pla e. Bone segmen s we e hen pulled away om each o he using he jig. Figu e 12a
shows a schema ic d awing o he expe imen . Figu e 12b shows he ac ual expe imen .
Appl. Sci. 2022, 12, x FOR PEER REVIEW 9 o 16
Figu e 12a shows a schema ic d awing o he expe imen . Figu e 12b shows he ac ual
expe imen .
Figu e 12. (a) A schema ic d awing o he expe imen (dimensions in mm); (b) Ac ual implemen a-
ion o he expe imen .
In he schema ic d awing, see Figu e 11a, dimension “A” de ails he dis ance o he
epiphyseal pla e om he op o he bone and he dimension “MAX. 90” is ela ed o he
limi s o he used es ing machine.
The uppe bone segmen in Figu e 11b was w apped in duc ape o acili a e manip-
ula ion be o e and du ing he expe imen .
Used equipmen :
• Model o ibia—SAWBONES, Tibia, 4 h Gen., Composi e, 17 PCF Solid Foam Co e;
see [27].
• S aples—p o ided by MEDIN, a.s.; see [20].
• Jig—M12 sc ew, M12 nu , washe (inne diame e 12 mm), ST12 sel - apping sc ew,
all p o ided by MEDIN, a.s.
• Uni e sal es ing machine—TESTOMETRIC M500-50CT; see [30].
The expe imen was conduc ed using de o ma ion-con olled loading wi h a con-
s an a e o jaw sepa a ion se o 10 mm/min.
3. Resul s o FEA
FEA was pe o med as desc ibed in Sec ion 2: Ma e ials and Me hods. The dis ibu-
ion o equi alen s ess ( on Mises) in he s aples was de e mined om he simula ion o
he bone g ow h es ic ion. The maximum s ess occu s in he s aple adius, see Figu es
13 and 14.
Figu e 12.
(
a
) A schema ic d awing o he expe imen (dimensions in mm); (
b
) Ac ual implemen a ion
o he expe imen .
In he schema ic d awing, see Figu e 11a, dimension “A” de ails he dis ance o he
epiphyseal pla e om he op o he bone and he dimension “MAX. 90” is ela ed o he
limi s o he used es ing machine.
The uppe bone segmen in Figu e 11b was w apped in duc ape o acili a e manipu-
la ion be o e and du ing he expe imen .
Used equipmen :
•
Model o ibia—SAWBONES, Tibia, 4 h Gen., Composi e, 17 PCF Solid Foam Co e;
see [27].
•S aples—p o ided by MEDIN, a.s.; see [20].
•
Jig—M12 sc ew, M12 nu , washe (inne diame e 12 mm), ST12 sel - apping sc ew, all
p o ided by MEDIN, a.s.
•Uni e sal es ing machine—TESTOMETRIC M500-50CT; see [30].
The expe imen was conduc ed using de o ma ion-con olled loading wi h a cons an
a e o jaw sepa a ion se o 10 mm/min.
3. Resul s o FEA
FEA was pe o med as desc ibed in Sec ion 2: Ma e ials and Me hods. The dis ibu-
ion o equi alen s ess ( on Mises) in he s aples was de e mined om he simula ion
o he bone g ow h es ic ion. The maximum s ess occu s in he s aple adius, see
Figu es 13 and 14.
The o al displacemen o s aples is p esen ed in Figu e 15. In ou case, he highes
o al displacemen is a he op end o he s aples and he maximum displacemen is highe
up in he medial s aple han in he la e al one. Based on he de ec ed de o ma ion, we can
measu e he dis ance be ween he bone segmen s om he epiphyseal pla e o ob ain a
ough es ima ion o how much he bone could g ow wi h he s aples applied. Figu e 16
shows he a e age maximum possible g ow h dis ance be ween bo h bone segmen s.
The acqui ed FEA esul s a e summa ized in Table 3.
Appl. Sci. 2022,12, 614 16 o 16
33.
F yd ýšek, K.; Michenko á, Š.; Ple a, L.; Kou ecký, J.; F ies, J.; Pe e ek Dˇedko á, K.; Madeja, R.; T e il, A.; K pec, P.; Halo, T.; e al.
Mechanics o Sc ew Join s Sol ed as Beams Placed in a Tangen ial Elas ic Founda ion. Appl. Sci. 2021,11, 5616. [C ossRe ]
34.
Theisz, G.; F yd ýšek, K.; Foj ík, F. Medial Pla e o T ea men o Dis al Tibia F ac u es. In P oceedings o he EAN 2015—53 d
Con e ence on Expe imen al S ess Analysis, Cesky K umlo , Czech Republic, 1–4 June 2015; Pade e , P., Bi na , P., Eds.; CTU in
P ague: ˇ
CeskýK umlo , Czech Republic; pp. 431–437, ISBN 978-800105735-6.
35.
Po hong, W.; Phinyo, P.; Si i ung uangsa n, Y.; Nabudda, K.; Wongba, N.; Sa n ipipha , C.; P uksako n, D. Biomechanical
Analysis o Sagi al Plane Pin Placemen Con igu a ions o Pedia ic Sup acondyla Hume us F ac u es. Appl. Sci.
2021
,11, 3447.
[C ossRe ]
36.
Kwon, J.; Ha, M.H.; Lee, M.G. Al e na i e Pedicle Sc ew Design ia Biomechanical E alua ion. Appl. Sci.
2020
,10, 4746.
[C ossRe ]
37.
ˇ
Cada, R.; F yd ýšek, K.; Sejda, F.; Demel, J.; Ple a, L. Analysis o locking sel - aping bone sc ews o angula ly s able pla es.
J. Med. Biol. Eng. 2017,37, 612–625. [C ossRe ] [PubMed]
38.
F yd ýšek, K.; Ší , M.; Ple a, L. S eng h Analyses o Sc ews o Femo al Neck F ac u es. J. Med. Biol. Eng.
2018
,38, 816–834.
[C ossRe ] [PubMed]
39.
F yd ýšek, K.; ˇ
Cepica, D.; Halo, T. Biomechanics—P obabilis ic An h opome y App oach o Si ing Human and Sea . In P o-
ceedings o he 57 h In e na ional Scien i ic Con e ence on Expe imen al S ess Analysis (EAN 2019), Luhaco ice, Czech Republic,
13–16 May 2019; pp. 90–96, ISBN 978-80-214-5766-9.
40.
Tai, W.-H.; Peng, H.-T.; Song, C.-Y.; Lin, J.-Z.; Yu, H.-B.; Wang, L.-I. Dynamic Cha ac e is ics o App oach Spike Jump Tasks in
Male Volleyball Playe s. Appl. Sci. 2021,11, 2710. [C ossRe ]