O iginal Resea ch
Biomechanical Beha io o an Hyd oxyapa i e-Coa ed T adi ional Hip
S em and a Sho One o Simila Design: Compa a i e S udy Using
Fini e Elemen Analysis
Jesús G
omez-Vallejo, MD, PhD
a
,
*
, Jo ge Roces-Ga cía, PhD
b
, Jesús Mo e a, MD, FEBOT
c
,
Daniel Donai e-Hoyas, MD
d
,

Osca Gayoso, MD
e
, Fe nando Ma qu
es-L
opez, MD, PhD
,
Jo ge Alba eda, MD, PhD
a
a
Depa men o O hopaedic Su ge y, Hospi al Clínico Uni e si a io Lozano Blesa, Za agoza, Spain
b
Depa men o Cons uc ion and Manu ac u ing Enginee ing, Uni e si y o O iedo, O iedo, Spain
c
G oup o Lowe Limb Recons uc i e Su ge y, Bioc uces Bizkaia Heal h Resea ch Ins i u e, Osakide za. Depa men o O hopaedic Su ge y and
T auma ology, Hospi al Galdakao-Usansolo, Bizkaia, Spain
d
Depa men o O hopaedic Su ge y, Hospi al de Ponien e, El Ejido, Spain
e
Depa men o O hopaedic Su ge y, Hospi al San Ra ael, La Co u~
na, Spain
Hip Recons uc ion Uni , Pa c de Salu Ma , Ba celona, Spain
a icle in o
A icle his o y:
Recei ed 20 Augus 2020
Recei ed in e ised o m
24 No embe 2020
Accep ed 25 No embe 2020
A ailable online xxx
Keywo ds:
Hip
Biomechanics
Sho s em
Fini e elemen s
Loading
THR
abs ac
Backg ound: The objec i e is o compa e, by he means o fini e elemen s analysis, he biomechanical
beha io o a con en ional s em o p o en pe o mance wi h a sho s em based on he same fixa ion
p inciples.
Me hods: A 3D emu was modeled om CT scan da a, and eal bone densi y measu es we e inco po-
a ed in o i . Load s esses we e applied o ha bone in 3 di e en scena ios: wi hou p os hesis, wi h he
con en ional s em, and wi h he sho s em. Di e en bone loading pa e ns we e compa ed by G uen’s
zones bo h isually and s a is ically using Welch’s es .
Resul s: The implan a ion o a s em gene a es a ce ain deg ee o s ess shielding in he su ounding
bone, bu he pa e n o he change is e y simila in he compa ed s em models. Al hough he e is
s a is ical significance (P<0.01) in he mean s ess a ia ion in mos o he G uen’s zones, he magni ude
o he di e ence is always unde 2 MPa ( ange: 0.01 e1.74 MPa).
Conclusions: The bone loading pa e ns o he adi ional s em and he sho s em a e e y simila .
Al hough he e is no e idence o a link be ween biomechanics and clinical ou comes, ou esul s may
sugges ha heo e ical ad an ages o sho s ems can be exploi ed wi hou he ea o al e ing bone
loading pa e ns.
©2020 The Au ho s. Published by Else ie Inc. on behal o The Ame ican Associa ion o Hip and Knee
Su geons. This is an open access a icle unde he CC BY-NC-ND license (h p://c ea i ecommons.o g/
licenses/by-nc-nd/4.0/).
In oduc ion
Al hough he esul s o o al hip a h oplas y a e excellen , wi h
mean su i al a es o o e 92% a 14 yea s [1], some aspec s o he
clinical pe o mance o con en ional s ems could be imp o ed,
such as he a e o ea ly pe ip os he ic ac u es [2,3], high pain [3-
6], p oximal s ess-shielding [3,6-9], and loss o bone s ock o
possible u u e e ision [3,6]. These issues ha e led o he appea -
ance on he ma ke o a wide a ie y o s ems aiming o educe
bone mass loss, achie e a mo e physiological load dis ibu ion, and
acili a e less agg essi e su gical app oaches [9-12]. These s ems
a e gene ically called sho s ems; howe e , his e m ep esen s a
e y he e ogeneous g oup wi h di e en designs, biomechanics,
and in asi eness [9,10,13,14].
Sho s ems a e no wi hou p oblems. Ce ain designs p ese -
ing he emo al neck equi e a mo e complex echnique [12,14-16]
and a e less ole an o placemen e o s, size selec ion, o le el o
*Co esponding au ho . Depa men o O hopaedic Su ge y, Hospi al Clínico
Uni e si a io Lozano Blesa, Za agoza, Spain. Tel.: þ34 630382461.
E-mail add ess: jgomez [email protected]
Con en s lis s a ailable a ScienceDi ec
A h oplas y Today
jou nal homepage: h p://www.a h oplas y oday.o g/
h ps://doi.o g/10.1016/j.a d.2020.11.022
2352-3441/©2020 The Au ho s. Published by Else ie Inc. on behal o The Ame ican Associa ion o Hip and Knee Su geons. This is an open access a icle unde he CC BY-
NC-ND license (h p://c ea i ecommons.o g/licenses/by-nc-nd/4.0/).
A h oplas y Today 7 (2021) 167e176
bone esec ion [10]. In addi ion, a high equency o poo alignmen
has been associa ed wi h some models [7]. As a esul , many su -
geons only use sho s ems in young pa ien s wi h good bone
quali y [10,14,17,18].
S udies using he fini e elemen me hod p o ide in o ma ion on
biomechanical beha io , in pa icula ega ding mic omo ion and
load ans e [19,20]. This me hod has also been used o s udy he
e ec o he colla , p esen in some p os he ic designs, on he
biomechanical beha io o he emo al implan [21].
The aim o his s udy is o compa e, using fini e elemen
me hod, he biomechanical beha io o a con en ional s em o
p o en pe o mance [1,15,22-24] wi h a sho s em design seeking
o educe bone mass loss in he ochan e and diaphysis bu
main aining he same fixa ion p inciples.
Ma e ials and me hods
A ozen emu om a 46-yea -old male indi idual wi hou
an eceden s o in e es was used o model he sys em unde s udy.
A compu e ized axial omog aphy scan o he emu was pe o med
o ob ain he bone densi y o he specimen in Hounsfield uni s [25-
27]. The da a we e inco po a ed in o a oxel model (cubic uni s
making up a h ee-dimensional objec ) using modVOX so wa e
(MBA, Inc. Gij
on, Spain). Voxel models allowed assigning he me-
chanical p ope ies o he di e en poin s o he o iginal bone
di ec ly o each indi idual model oxel, ha ing a spa ial posi ion (x,
y, z) o which he bone densi y ob ained om he base omog aphy
was assigned.
The s ems o be compa ed we e also modeled, including in o -
ma ion ega ding hei composi ion. The ollowing implan s we e
used (Fig. 1):
Fu long H-A.C. (JRI O hopedics L d., She field, Uni ed
Kingdom): hyd oxyapa i e-coa ed i anium s em, 152 mm long,
fi ed wi h a colla . I s p ima y fixa ion is based on a
quad angula me aphysis and a long s em, joined by a ape ed
ansi ion zone;
Fu long E olu ion, colla less e sion (JRI O hopedics L d.,
She field, Uni ed Kingdom): hyd oxyapa i e-coa ed i anium,
100 mm long; i has a la e ally educed me aphysis, and i s
medial cu e p esen s a bigge adius. While i main ains he
ape ed ansi ion zone, s em is me ely es imonial; and
Fu long E olu ion, e sion wi h a colla (JRI O hopedics L d.,
She field, Uni ed Kingdom): Iden ical o he p e ious one, bu
wi h a colla .
Bo h sho s ems ha e been designed o p ese e maximum
bone mass and can be inse ed wi h a simple su gical echnique,
wi hou he need o p epa e he an i o a ion ab in he
ochan e .
Digi al bone p epa a ion and implan posi ioning we e pe -
o med acco ding o he s anda d su gical echnique, as ag eed by
all he au ho s. Two ypes o models we e ob ained: One was a
emu model be o e s em placemen , and he second was a emu
model wi h each o he 3 s ems used. These oxel models we e
expo ed o exchange files ha could be in e p e ed by Ansys
so wa e (Ansys Inc., Canonsbu g, PA) o de e mine in e nal bone
s esses be ween bone and s em.
In he fini e elemen analyses, he bounda y condi ions defined
by Be gmann e al [28], which include he o ces exe ed by he
join and abduc o muscles, we e conside ed in he models. Bone
fixa ion was pe o med on he ou e nodes o he dis al emu , om
he condyles o a dimension o 150 mm [29].
The analysis esul s p o ided in o ma ion on bone s ess in he
nonope a ed emu and in hose wi h he di e en ypes o s ems
implan ed. As hese da a we e assigned o elemen s wi h a defined
spa ial loca ion (x, y, z), i was possible o compa e he s ess
change p oduced in each bone elemen be o e and a e implan-
a ion o each p os he ic model.
A quali a i e and a quan i a i e me hod has been chosen o
in e p e he esul s.
Figu e 1. The 3 s ems compa ed in he s udy: Fu long H-A.C., colla less Fu long E olu ion, and colla ed Fu long E olu ion.
J. G
omez-Vallejo e al. / A h oplas y Today 7 (2021) 167e176168
Quali a i ely, isual analysis o a g aphic ep esen a ion o he
s ess a ia ions obse ed in he bone when implan ing each ype
o s em was used o e alua e he implica ion o he findings. VTO3D
so wa e gene a es a oxel o each compa able node, assigning i
o a laye wi h a ce ain colo depending on he s ess de ia ion.
The changes we e s udied based on he G uen zones in he an e-
opos e io and la e al iews (zones 1-14) [30].
Quan i a i ely, he oxels we e segmen ed acco ding o he
G uen zones in he an e opos e io iew [31], and he mean s ess
change in each o hose zones was calcula ed o each ype o s em.
Fo compa a i e easons, he zones o iginally desc ibed by G uen
we e used o bo h he con en ional and sho s ems. The me hod
desc ibed by Roces-Ga cía e al [32] was used o analyze he sim-
ila i ies and di e ences be ween he biomechanical beha io o he
con en ional and sho s ems.
Because he s ess changes (inc ease, dec ease, o in a iable) a e
di e en o each elemen , hese we e g ouped in o anges o
ca ego ies o simpli y he analysis. To de e mine easonable anges
o s ess a ia ion, we elied on he U ah pa adigm and mechano-
s a hypo hesis [33], acco ding o which mechanical s imuli a e he
essen ial ac o s o hei de e mina ion. The o ces ac ing on he
bone cause small s ains, which esul in an adap i e esponse by
he bone. F os [33] desc ibed bone modeling h esholds based on
he amoun o mic os ain su e ed wi h espec o he o al leng h:
Bone eso p ion occu s below 1 o 2 MPa (50-100
m
ε), ne bone
o ma ion occu s abo e 20 MPa (1000
m
ε), and he emodeling a e
is s able be ween hese alues, wi h nei he bone o ma ion no
eso p ion [33](Fig. 2).
Fo he p esen analysis, i was assumed ha indi iduals un-
de going hip eplacemen su ge y a e no mally dis ibu ed wi hin
he s ess ange o he adap ed window in so-called adap ed adul s,
wi h hei bones in a s a e o ela i e s abili y and bea ing physi-
ological loads be ween 2 and 20 MPa [33]. I has been assumed ha
he le el o s ess change ha would ensu e any indi idual mo ing
om ela i e s abili y o a local s a e o bone o ma ion o eso p-
ion would be g ea e han ±20 MPa. Changes be ween 5 and 20
MPa wi h espec o baseline condi ions ha e been conside ed
mino and a e ep esen ed g aphically as such.
The analysis o s ess a ia ions was di ided in o 4 di e en ia ed
g oups acco ding o Table 1.
Impo ing hese models in o a compu e -aided design en i-
onmen made i possible o con ol he isualiza ion, colo s, and
anspa ency le els in he G uen zones. The changes induced in he
bone en i onmen by each s em model we e s udied, p edic ing
hei e ec s on bone acco ding o he mechanos a hypo hesis [33].
Simila ly, bone emodeling pa e ns we e analyzed o each ype o
implan o pe o m a compa a i e analysis be ween hem.
Fo he s a is ical analysis, a di e ence in means es was pe -
o med be ween he di e en s ems and o each G uen zone.
Le ene’s es was pe o med o compa e he a iance be ween he
di e en compa ison g oups, e i ying he nonexis ence o homo-
scedas ici y. G oup compa isons we e pe o med wi h Welch’s es ,
Table 1
Tensional a ia ions wi h espec o nonp os he ized bone (colo code).
Colo Desc ip ion Bone s ess In e p e a ion
Rele an s ess inc ease △20 MPa Bone o ma ion in mos people.
Mild s ess inc ease △5-15 MPa Bone o ma ion in people who a e abo e a e age.
Mild s ess educ ion ▽5-15 MPa Bone eso p ion in people who a e below a e age.
Rele an s ess educ ion ▽20 MPa Bone eso p ion in mos people.
Figu e 2. Bone beha io unde s ess acco ding o he U ah pa adigm and he mechanos a hypo hesis.
J. G
omez-Vallejo e al. / A h oplas y Today 7 (2021) 167e176 169
and pos hoc con as s we e based on he Games-Howell es . All
calcula ions we e pe o med wi h SPSS .24 (IBM, New Yo k, NY).
Resul s
Quali a i e analysis
G uen zones a e shown in he an e opos e io and la e al iews
[30].
S ess dec eases abo e 20 MPa
The 3 s ems gene a ed s ess dec eases g ea e han 20 MPa in
a eas 7, 14, and 13. Acco ding o he c i e ia al eady desc ibed, his
would in ol e some deg ee o bone eso p ion, depending on he
e ec s o he p e ious s a e o each indi idual. This dec ease in he
loads bo ne by he bone is mo e p onounced in sho s ems (Figs. 3
and 4). In addi ion, a sligh di e ence in he loading pa e n is
de ec ed in he con en ional s em, o e ing less p o ec ion agains
s ess in he cen al zone o ha a ea (Fig. 3).
The da a in Table 2 show he s ess dec ease ex ends o e a la ge
a ea in he case o sho s ems (mo e oxels wi h a s ess dec ease). I
is also obse ed ha o he con en ional s em, p o ec ion agains
s ess is mo e isible in a ea 7 below he colla (Fig. 4).
The colla does no seem o ha e an impo an e ec on load
ans e o he bone, as he e a e ha dly any di e ences be ween he
loading pa e ns o he 2 sho s ems (wi h and wi hou a colla ).
S ess inc eases abo e 20 MPa
The e we e no a eas wi h s ess inc eases abo e he ele an
h eshold in any o he s ems conside ed.
S ess dec eases be ween 5 and 20 MPa
The sligh s ess dec ease ollows a simila pa e n in all models.
I occu s in he an e io zone o he ochan e ic massi (zones 1 and
8), as well as in a eas 3 and 5. In all he s ems, he mode a e s ess
dec ease ex ends dis ally wi h espec o he s em, hus a ec ing a
la ge a ea in he con en ional s em (Table 2 and Fig. 5)
In he pos e io emo al egion, he e is also a sligh s ess
dec ease along he implan (zones 12 and 13). This p o ec ion
agains s ess also occu s in sho s ems, bu gi en he sho e
leng h, he a ec ed a ea is much smalle (Table 2 and Fig. 5).
The an e io a ea o he diaphysis does no show s ess changes
in any o he implan s, including he long s em.
A small di e ence be ween he con en ional and sho s ems is
a zone o sligh s ess dec ease a he p oximal edge o he
os eo omy, in he pos e io emo al egion (Table 2 and Fig. 5).
S ess inc eases be ween 5 and 20 MPa
All s ems gene a e an a ea o mode a e s ess inc ease in he
medial and la e al aspec s o he emo al sha , zone 4 (Fig. 6). This
a ea begins jus below he dis al end o he con en ional s em and
may seem ela ed o his finding, bu i is also p esen in sho s ems
and appea s a he same heigh (al hough i s ex ension is some-
wha g ea e in he con en ional s em).
Figu e 4. Rele an s ess educ ion a ea in he 3 compa ed s ems (axial iew). F om le o igh : E olu ion (colla ed), E olu ion, Fu long H-A.C.
Figu e 3. Rele an s ess educ ion a ea in he 3 compa ed s ems ( h ee qua e s iew). F om le o igh : E olu ion (colla ed), E olu ion, Fu long H-A.C.
J. G
omez-Vallejo e al. / A h oplas y Today 7 (2021) 167e176170
Figu e 5. Mild s ess educ ion a ea in he 3 compa ed s ems. F om op o bo om: E olu ion (colla ed), E olu ion, Fu long H-A.C.
J. G
omez-Vallejo e al. / A h oplas y Today 7 (2021) 167e176 171

A e y small a ea o s ess inc ease also appea s in all models a
he supe io -pos e ola e al po ion o he p os hesis (zones 1 and
14). This occu s independen ly o he geome y o he implan ,
al hough he E olu ion s ems ha e a smalle shoulde o acili a e
inse ion, a oiding he a ea o he g ea e ochan e .
Quan i a i e analysis
A e g ouping he fini e elemen s acco ding o he G uen zone
o which hey belong, he mean s ess a ia ion was calcula ed o
each s em in each G uen zone [31]. The 95% confidence in e al was
also calcula ed, and a di e ence in means es was pe o med. The
esul s a e shown in Table 3 and Figu e 7.
S a is ical analysis e ealed significan di e ences in all zones
o he 3 s ems. Howe e , hese di e ences we e e y small
because o he amoun o da a ob ained and should no imply majo
changes ega ding bone beha io acco ding o accep ed p inciples.
S ess changes close o 1 MPa o highe ha e been selec ed,
shown in blue in Table 3 and Figu e 8. To ep esen hose zones
whe e he changes a e mino , we ha e indica ed in yellow he a eas
whe e he changes do no each s a is ical significance (which a e
also e y close o 0 MPa).
The bigges changes occu ed in G uen zones 3, 6, and 7 when
compa ing he con en ional and sho s ems. Sho s ems sligh ly
educe s esses below he p os hesis while keeping hem some-
wha s able in he me aphysis.
Table 2
Numbe o oxels acco ding o he ype o ensional change p oduced and segmen ed by a ea o G uen.
S em G uen zone Numbe o oxels
Inc ease o ension Reduc ion o ension No ensional change To al
Fu long H-A.C. 1 5454 42,107 60 47,621
2 622 17,570 0 18,192
3 2543 17,435 2 19,980
4 29,127 12,762 20 41,909
5 7872 12,896 3 20,771
6 372 14,627 1 15,000
7 14 26,014 0 26,028
E olu ion 1 6299 37,759 67 44,125
2 714 15,241 1 15,956
3 11,401 13,528 21 24,950
4 29,403 12,474 32 41,909
5 9314 16,916 17 26,247
6 350 15,644 0 15,994
7 59 24,786 0 24,845
E olu ion (wi h colla ) 1 6253 37,789 61 44,103
2 709 15,209 2 15,920
3 10,976 13,955 19 24,950
4 29,040 12,850 19 41,909
5 8971 17,256 20 26,247
6 343 15,701 0 16,044
7 45 24,532 0 24,577
Figu e 6. Mild s ess inc ease was no ed along he emo al sha o all 3 s em designs. F om le o igh : E olu ion (colla ed), Fu long H-A.C., E olu ion.
J. G
omez-Vallejo e al. / A h oplas y Today 7 (2021) 167e176172
Table 3
Mean ension di e ences be ween di e en s ems by G uen zones.
G uen zone Compa ed s ems Mean di e ence Absolu e alue (mean di e ence) Sig. (P)
S em A S em B
1 Fu long H-A.C. E olu ion 0,10945 0,10945 0.000
E olu ion (colla ) 0,10065 0,10065 0.000
E olu ion Fu long H-A.C. 0,10945 0,10945 0.000
E olu ion (colla ) 0,00880 0,00880 0.890
E olu ion (colla ) Fu long H-A.C. 0,10065 0,10065 0.000
E olu ion 0,00880 0,00880 0.890
2 Fu long H-A.C. E olu ion 0,17173 0,17173 0.000
E olu ion (colla ) 0,25919 0,25919 0.000
E olu ion Fu long H-A.C. 0,17173 0,17173 0.000
E olu ion (colla ) 0,08745 0,08745 0.048
E olu ion (colla ) Fu long H-A.C. 0,25919 0,25919 0.000
E olu ion 0,08745 0,08745 0.048
3 Fu long H-A.C. E olu ion 1,69292 1,69292 0.000
E olu ion (colla ) 1,67270 1,67270 0.000
E olu ion Fu long H-A.C. 1,69292 1,69292 0.000
E olu ion (colla ) 0,02021 0,02021 0.563
E olu ion (colla ) Fu long H-A.C. 1,67270 1,67270 0.000
E olu ion 0,02021 0,02021 0.563
4 Fu long H-A.C. E olu ion 0,47471 0,47471 0.000
E olu ion (colla ) 0,64009 0,64009 0.000
E olu ion Fu long H-A.C. 0,47471 0,47471 0.000
E olu ion (colla ) 0,16538 0,16538 0.000
E olu ion (colla ) Fu long H-A.C. 0,64009 0,64009 0.000
E olu ion 0,16538 0,16538 0.000
5 Fu long H-A.C. E olu ion 0,49722 0,49722 0.000
E olu ion (colla ) 0,33948 0,33948 0.000
E olu ion Fu long H-A.C. 0,49722 0,49722 0.000
E olu ion (colla ) 0,15774 0,15774 0.010
E olu ion (colla ) Fu long H-A.C. 0,33948 0,33948 0.000
E olu ion 0,15774 0,15774 0.010
6 Fu long H-A.C. E olu ion 0,99695 0,99695 0.000
E olu ion (colla ) 1,14925 1,14925 0.000
E olu ion Fu long H-A.C. 0,99695 0,99695 0.000
E olu ion (colla ) 0,15230 0,15230 0.035
E olu ion (colla ) Fu long H-A.C. 1,14925 1,14925 0.000
E olu ion 0,15230 0,15230 0.035
7 Fu long H-A.C. E olu ion 1,72197 1,72197 0.000
E olu ion (colla ) 1,73798 1,73798 0.000
E olu ion Fu long H-A.C. 1,72197 1,72197 0.000
E olu ion (colla ) 0,01602 0,01602 0.695
E olu ion (colla ) Fu long H-A.C. 1,73798 1,73798 0.000
E olu ion 0,01602 0,01602 0.695
Figu e 7. Mean ensional a ia ion be ween he di e en s ems by G uen’s zones.
J. G
omez-Vallejo e al. / A h oplas y Today 7 (2021) 167e176 173
Discussion
F om he biomechanical poin o iew, he ideal implan
should eplica e he physiological pa e n o load ans e along
he emaining bone a e placemen [6,34]. Howe e , he im-
plan a ion o any p os he ic model a ec s load ans e , usually
causing p oximal unloading o he s em and s ess ans e o he
dis al egion [34-38]. The ypical ou come o his load ans e is
me aphyseal bone eso p ion (wi h a ophy o he calca and
co ex o he p oximal emu ) and co ical hype ophy a he
dis al end o he s em [34]. This is consis en wi h he obse a-
ions in ou models because he only clinically ele an s ess
dec eases (abo e 20 MPa, as we ha e defined) occu in G uen
zone 7.
Figu e 8. G uen zones wi h and wi hou s a is ical significance s ess a ia ion.
J. G
omez-Vallejo e al. / A h oplas y Today 7 (2021) 167e176174
This s udy aims o analyze whe he he biomechanical beha io
o a “sho ”s em (Fu long E olu ion wi h and wi hou colla ) di e s
om he p e ious design (Fu long H-A.C.). A he me aphysis
(G uen zones 1 and 7), he quan i a i e compa ison o mean s ess
change be ween he s ems analyzed, al hough s a is ically signifi-
can , is o a e y low magni ude (0.11 MPa in zone 1 and 1.74 MPa in
zone 7; Table 3); he e o e, i would no ha e any clinical ele ance
[33]. This is consis en wi h he esul s ound in o he s udies
minimizing he clinical impo ance o he colla [21,39].
In G uen zone 1 (g ea e ochan e ), he e a e no significan
s ess changes. Al hough he sho s em s udied has a educed
la e al shoulde , he mean s ess change in zone 1 is p ac ically ze o
(0.11 MPa). Thus, his modifica ion can be in e p e ed as posi i e
because i does no al e he biomechanics o he a ea bu acili a es
implan inse ion; i does no weaken he ochan e ic bone and
p e en s p epa ing he an i o a ion ab p esen in he con en ional
s em.
A he emo al sha , he e a e clea di e ences be ween he
Fu long H-A.C. s em and Fu long E olu ion sho s em designs,
whe e he s ess pa e n o sho s ems is much mo e simila o ha
o nonp os he ic bone. This also coincides wi h he esul s o p e-
ious s udies, in which hip implan s wi h sho e s ems end o
induce less s ess shielding and be e eplica e he physiological
bone condi ion [40-43]. When changes in he physiological
emodeling pa e n a e e y la ge, highe a es o asep ic loosening
and pe ip os he ic ac u es would be expec ed, hinde ing e ision
su ge y [34]. The e o e, sho s ems could be ecommended om
his poin o iew. The s ess di e ence be ween con en ional and
sho s ems is g ea e (1.69 MPa) in he emo al sha (G uen zone
3), al hough no eaching physiologically ele an le els [33].
The isual and quan i a i e analyses pe o med show e y
simila pa e ns o bone s ess changes o he 3 p os he ic models
conside ed and a e p ac ically iden ical o he 2 sho s em e -
sions (wi h and wi hou a colla ). Al hough he e is s ill no e idence
ha clinical esul s a e ela ed o changes in bone emodeling
pa e ns [34], ou s udy demons a es he g ea simila i ies exis ing
in he biomechanical beha io o con en ional and sho s ems.
Load dis ibu ion in he me aphysis is e y simila , and al hough
he di e ences a e somewha la ge in he diaphysis, hey a e e y
small. In addi ion, s ess beha io wi h he sho s em mo e e-
sembles ha unde physiological condi ions; he e o e, i could
heo e ically imp o e he clinical esul s o he implan .
We mus bea in mind he p esen s udy has some limi a ions.
Fi s , he e is no e idence linking bone emodeling o clinical
ou comes [36]. Thus, we ha e p oposed a compa ison wi h a s em
wi h p o en clinical esul s, assuming a simila biomechanical
beha io will ha e posi i e e ec s on pa ien s. Second, an indi-
idual componen is in ol ed in bone emodeling ha does no
depend only on he implan [34,36,44]. Thi d, i should be
men ioned ha he es s ha e been pe o med on a single emu ,
assuming he popula ion o subjec s unde going o al hip a h o-
plas y is no mally dis ibu ed ac oss he ange o s esses o he
adap ed window in adul s, which may be an o e simplifica ion.
Conclusions
Ou s udy analyzes he influence o implan ing emo al s ems
wi h di e en geome ies, bu simila fixa ion philosophies, on
bone s esses o he emu . Al hough he e is no e idence o a link
be ween biomechanics and clinical ou comes [36], es ablishing he
biomechanical simila i y be ween 2 implan s could imply simila
long- e m clinical beha io wi h he men ioned ad an ages o
easie implan a ion. In conclusion, al hough he e a e significan
di e ences in he s ess changes p oduced by he 3 p os he ic
models on he bone, hese a e so small ha hey p obably ha e
ela i ely li le influence on he biology o he su ounding bone.
Conflic o in e es s
The au ho s decla e he e a e no conflic s o in e es .
Acknowledgmen s
The au ho s would like o hank Ma ía Rabanal Rubio and Pablo
Roza Miguel o hei collabo a ion in planning his s udy and
p epa ing he d a s.
Re e ences
[1] No au ho s lis ed, Na ional Join Regis y. 15 h Annual Repo 2018. 15 h
Annu Rep. London: Pad C ea i e L d.; 2018.
[2] Jones C, Aqil A, Cla ke S, Cobb JP. Sho uncemen ed s ems allow g ea e
emo al flexibili y and may educe pe i-p os he ic ac u e isk: a d y bone
and cada e ic s udy. J O hop T auma ol 2015;16:229.
[3] Liang H-D, Yang W-Y, Pan J-K, e al. A e sho -s em p os heses supe io o con-
en ional s em p os heses in p ima y o al hip a h oplas y? A sys ema ic e iew
and me a-analysis o andomised con olled ials. BMJ Open 2018;8:e021649.
[4] Huo S-C, Wang F, Dong L-J, e al. Sho -s em p os heses in p ima y o al hip
a h oplas y. Medicine (Bal imo e) 2016;95:e5215.
[5] La e nia C, D’Apuzzo M, He nandez V, Lee D. Thigh pain in p ima y o al hip
a h oplas y. J A h oplas y 2004;19:10.
[6] Pogliacomi F, Schia i P, G appiolo G, e al. Ou come o sho e sus con en-
ional s em o o al hip a h oplas y in he emu wi h a high co ical index: a
fi e yea ollow-up p ospec i e mul icen e compa a i e s udy. In O hop
2020;44:61.
[7] en B oeke RHM, Ta ala M, A s JJ, e al. Imp o ing pe i-p os he ic bone
adap a ion a ound cemen less hip s ems: a clinical and fini e elemen s udy.
Med Eng Phys 2014;36:345.
[8] T an P, Zhang BX, Lade JA, e al. Pe ip os he ic bone emodeling a e no el
sho -s em neck-spa ing o al hip a h oplas y. J A h oplas y 2016;31:2530.
[9] Yan SG, Webe P, S einb ück A, e al. Pe ip os he ic bone emodelling o sho -
s em o al hip a h oplas y: a sys ema ic e iew. In O hop 2018;42:2077.
[10] Loppini M, G appiolo G. Uncemen ed sho s ems in p ima y o al hip
a h oplas y. EFORT Open Re 2018;3:149.
[11] an Olden ijk J, Molleman J, Kla e M, e al. Re ision a e a e sho -s em
o al hip a h oplas y. Ac a O hop 2014;85:250.
[12] McTighe T. Sho -s em designs o o al hip a h oplas y: neck s abilized
emo al componen s. In: Callaghan JJ, Rosenbe g AG, Rubash HE, Clohisy JC,
Paul E, Beaule CJDV, edi o s. The adul hip “hip a h oplas y su ge y”. 3 d ed.
Philadelphia: Wol e s Kluwe ; 2016. p. 823.
[13] Falez F, Casella F, Papalia M. Cu en concep s, classifica ion, and esul s in
sho s em hip a h oplas y. O hopedics 2015;38:S6.
[14] Khanuja HS, Bane jee S, Jain D, e al. Sho bone-conse ing s ems in
cemen less hip a h oplas y. J Bone Join Su g Am 2014;96:1742.
[15] Syed MA, Hu NJ, Shah N, Edge AJ. Hyd oxyapa i e ce amic-coa ed emo al
componen s in young pa ien s ollowed up o 17 o 25 yea s: an upda e o a
p e ious epo . Bone Join J 2015;97-B:749.
[16] Bane jee S, Pi ec R, Issa K, e al. Ou comes o sho s ems in o al hip
a h oplas y. O hopedics 2013;36:700.
[17] Goebel D, Schul z W. The Mayo cemen less emo al componen in ac i e
pa ien s wi h os eoa h i is. Hip In 2009;19:206.
[18] Mo ey BF, Adams RA, Kessle M. A conse a i e emo al eplacemen o o al
hip a h oplas y. J Bone Join Su g B 2000;82:952.
[19] Vicecon i M, Muccini R, Be nakiewicz M, e al. La ge-sliding con ac elemen s
accu a ely p edic le els o boneeimplan mic omo ion ele an o osseoin-
eg a ion. J Biomech 2000;33:1611.
[20] Kea eny TM, Ba el DL. E ec s o po ous coa ing and colla suppo on ea ly
load ans e o a cemen less hip p os hesis. J Biomech 1993;26:1205.
[21] Al-Di ini RMA, Hu D, Zhang J, e al. Influence o colla s on he p ima y s a-
bili y o cemen less emo al s ems: a fini e elemen s udy using a di e se
pa ien coho . J O hop Res 2018;36:1185.
[22] Sandi o d N, Doc o C, Raja a nam SS, e al. P ima y o al hip eplacemen
wi h a Fu long ully hyd oxyapa i e-coa ed i anium alloy emo al compo-
nen : esul s a a minimum ollow-up o 20 yea s. Bone Join J 2013;95-B:467.
[23] Raja a nam SS, Jack C, Ta akkolizadeh A, e al. Long- e m esul s o a
hyd oxyapa i e-coa ed emo al componen in o al hip eplacemen . J Bone
Join Su g B 2008;90-B:27.
[24] She y AA, Slack R, Tindall A, e al. Resul s o a hyd oxyapa i e-coa ed
(Fu long) o al hip eplacemen . J Bone Join Su g B 2005;87-B:1050.
[25] Zannoni C, Man o ani R, Vicecon i M. Ma e ial p ope ies assignmen o fini e
elemen models o bone s uc u es: a new me hod. Med Eng Phys 1999;20:735.
[26] Cowin S, Telega J. Bone Mechanics Handbook. 2nd ed. New Yo k: Appl Mech
Re ; 2003.
J. G
omez-Vallejo e al. / A h oplas y Today 7 (2021) 167e176 175