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LENGTH OF THE FIRST METATARSAL AND HALLUX IN HALLUX
VALGUS IN INITIAL STAGE
AUTHORS:
Ped o V. Munue a (Co esponding au ho ). G adua e in Podia ics and Ph.D. (by
Uni e si y o Se ille). Lec u e , Depa men o Podia ics. Uni e si y o Se ille. Spain.
Add ess: Cen o Docen e de Fisio e apia y Podología
C/ A icena, s/n. 41009 Se illa (España)
Telephone: +34 954 48 65 44
Fax: +34 954 48 65 27
E-mail: pm[email p o ec ed]
Juan Polo. Ph.D. Ma hema ics. P o esso , Depa men o Socio-Heal h Sciences.
Uni e si y o Se ille. Spain.
Add ess: Facul ad de Medicina. Dp o de Ciencias socio-sani a ias
A da. Sánchez Pizjuán, s/n. 41009 Se illa (España)
Jesús Rebollo. Physio he apis and Ph.D. (by Uni e si y o Se ille). P o esso ,
Depa men o Physio he apy. Uni e si y o Se ille. Spain.
Add ess: Cen o Docen e de Fisio e apia y Podología
C/ A icena, s/n. 41009 Se illa (España)
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ABSTRACT
The aim o his s udy is o con i m whe he he leng h o he i s me a a sal and he
leng h o he hallux a e g ea e han no mal in he ini ial phase o he hallux algus
de o mi y. In a sample o 152 adiog aphs (98 o no mal ee and 54 o incipien hallux
algus ee ), he leng h o he i s me a a sal and he hallux was measu ed acco ding o
me hods p e iously desc ibed. Compa isons we e made be ween no mal and hallux
algus ee , and be ween male and emale ee . The esul s show signi ican di e ences
be ween he wo g oups in he i s me a a sal (P < 0.0001) and hallux (P < 0.001). In
he male ee , hese di e ences a e mo e ma ked (when compa ing he leng h o he
hallux be ween he emale hallux algus ee and he emale no mal ee , P > 0.05). This
indica e ha in men wi h hallux algus, he excess in leng h o he i s me a a so-digi al
segmen is g ea e han in women ha p esen his de o mi y, a leas in i s ini ial phase.
Acco ding o hese esul s, he size o he i s me a a so-digi al segmen could be
in ol ed in he de elopmen o he hallux algus de o mi y.
INTRODUCTION
Many au ho s ha e e e ed in he podia ic and medical li e a u e o an excessi ely
long o excessi ely sho i s me a a sal as an e iology o hallux algus. Excessi e
leng h o he i s me a a sal wi h espec o he second has been associa ed o hallux
algus [9, 10, 13, 14] mo e o en han has a sho i s me a a sal ela i e o he second
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[23]. We also ind au ho s who do no associa e an al e a ion in he p o usion o he
i s me a a sal wi h hallux algus [2, 3].
When a i s me a a sal bone is said o be excessi ely long in absolu e leng h, i does no
mean ha i is longe han he second, a he ha he i s me a a sal is longe han
no mal, while s ill sho e han he second. The associa ion o an excessi e absolu e
leng h o he i s me a a sal and he de o mi y o hallux algus has been epo ed
p e iously [22]. Howe e , he e a e also au ho s who s a e ha in ee wi h his
de o mi y, he i s me a a sal is no longe han he second, a he i has a g ea e
ela i e p o usion [14]. Pa adoxically, an excessi ely sho i s me a a sal has also
been a ibu ed o he e iology o hallux algus [23]. Also he al e a ion in he leng h o
he hallux has been ela ed wi h he e iology o hallux algus, speci ically an excessi e
leng h [8, 10, 18, 22].
In iew o he di e en opinions in he li e a u e ega ding his ma e , he p esen s udy
was designed wi h he ollowing aims: (1) o es ablish no mal alues o he leng hs o
he i s me a a sal and hallux; (2) o con i m whe he he leng hs, absolu e o ela i e,
o he i s me a a sal and hallux a e g ea e han no mal in he ini ial phase o he hallux
algus de o mi y, and (3) o assess he ela ionship be ween he la e al de ia ion o he
g ea oe and he leng h o he i s me a a sal and hallux.
MATERIALS AND METHODS
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The subjec s o he sample in his s udy we e pa ien s a ending he Clinical Podia ic
Se ice a he Uni e si y o Se ille since Janua y 2004 o Janua y 2006, and podia y
s uden s who olun ee ed o ake pa in he esea ch du ing he same pe iod. A e
ag eeing o pa icipa e in he s udy, each subjec was asked o gi e w i en consen . This
wo k has been app o ed by he Expe imen al E hics Commi ee o he Uni e si y o
Se ille.
The subjec s pa icipa ing in he s udy had o ul ill he ollowing inclusion c i e ia: (1)
o be in he hi d decade o li e (20-29 yea s), so ha he g ow h physes had closed [20];
(2) ne e o ha e unde gone os eoa icula su ge y o he oo ; (3) ne e o ha e
su e ed se ious auma isms o he oo ha migh ha e al e ed i s bone mo phology;
(4) no o su e om degene a i e os eoa icula diseases o neu omuscula imbalance;
and (5) no o p esen e iden de o mi ies o he o e oo ha could a ec he esul s o
he s udy. Fi s , subjec s we e ec ui ed and adiog aphed. Then, he hallux abduc us
angle (hence o h, HAA) and hallux do si lexion we e measu ed so ha hey would be
alloca ed o one o he wo s udy g oups: a con ol g oup and a g oup o ee wi h hallux
algus (hence o h, HV g oup). The subjec s comp ising he con ol g oup had o ha e a
hallux do si lexion o 65º o mo e, and a no mal HAA  ha is, equal o o less han
15º [4]. The subjec s o he HV g oup had o p esen an HAA g ea e han 15º and less
han 30º. This ange was es ablished acco ding o he mild condi ion o hallux algus
p e iously epo ed [11]. A o al o 92 subjec s (184 ee ) we e ini ially included. HAA
alues o 14º, 15º, and 16º we e elimina ed in an a emp o educe e o p obabili y in
he measu ing p ocedu e, due o he p oximi y o hose alues o he limi be ween
no mal and abno mal abduc ion o he hallux. O he 152 es ing ee (76 subjec s), 98
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o med he con ol g oup (49 subjec s) and 54 he HV g oup (27 subjec s). All he cases
we e bila e al.
A do soplan a weigh bea ing adiog aph was aken o each indi idual, wi h bo h ee
oge he , wi h he ube inclined 15º o he e ical and a a ube- o-objec dis ance o one
me e . A digi al image o each adiog aph was made using a scanne , allowing he
explo a ion o images on posi i e ilm. The adiog aphic measu emen s we e made
using he Au oCAD® so wa e (Au oCAD 2006; Au odesk Inc, San Ra ael, Cali o nia),
o p o en e icacy o his ask [17]. The ollowing a iables we e s udied: ela i e
p o usion o he i s me a a sal, leng h o he i s me a a sal, leng h o he p oximal
phalanx o he hallux, leng h o he dis al phalanx o he hallux, and leng h o he hallux
(ob ained om he sum o he leng hs o he p oximal and dis al phalanges o he
hallux). O he measu emen s made we e he HAA and he leng h o he second
me a a sal. All measu emen s we e made by he same obse e .
All he adiog aphic pa ame e s we e measu ed in acco d wi h p e iously desc ibed
p ocedu es: HAA [4], he ela i e i s me a a sal p o usion [9] ( igu e 1), he leng hs
o he i s and second me a a sals [10] ( igu e 2), he leng h o he p oximal phalanx o
he hallux [21] ( igu e 3), as well as he leng h o he dis al phalanx [5].
To s anda dize he se o measu emen s o he leng h o he i s me a a sal, o he
p oximal and dis al phalanges o he hallux, and o he hallux, hese measu emen s ha e
also been exp essed as a pe cen age o he o al leng h o he second me a a sal. These
a iables ha e been denomina ed “ ela i e”, o dis inguish hem om he absolu e
alues.

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To check he ep oducibili y o he measu emen p ocedu e, i e adiog aphs we e
chosen a andom om each g oup, and he measu emen s we e made on h ee
occasions, wi h in e als o a week be ween measu emen s. The da a ob ained om his
g oup o measu emen s was used o calcula e he in aclass co ela ion coe icien . The
desc ip i e analysis ga e he mean, s anda d de ia ion, and in e al o con idence o
95% o each a iable. To decide whe he o use pa ame ic o non-pa ame ic es s, he
Kolmogo o -Smi no es was pe o med as a check o no mali y. I s esul sugges ed
ha he -S uden es o independen samples was he bes o use o compa ing he
means be ween he con ol g oup and he HV g oup, because he da a ollowed a no mal
dis ibu ion. The es o Le ene was used o he equali y o a iance. Pea son
co ela ion coe icien s we e calcula ed o assess he deg ee o ela ionship be ween he
HAA and leng h o he i s me a a sal, p o usion o he i s me a a sal, leng hs o he
p oximal and dis al phalanges o he hallux, and leng h o he hallux. P alues below
0.05 we e conside ed s a is ically signi ican . The da a we e analyzed using he so wa e
package SPSS 12.0 o Windows (SPSS Science, Chicago, Illinois).
RESULTS
The alue o he in aclass co ela ion coe icien was g ea e han 0.95 o all he
a iables measu ed on he adiog aphs. All hese coe icien s can be conside ed e y
high, so ha he ep oducibili y o he measu emen s is accep able wi h he me hods
used.
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The con ol g oup comp ised 98 ee o 49 subjec s, 19 men and 30 women, wi h a
mean age o 23.44 ± 2.85 yea s. The HV g oup comp ised 54 ee o 27 subjec s, 11
men and 16 women, wi h a mean age o 23.15 ± 2.22 yea s.
The alues om he desc ip i e analysis o he a iables (absolu e and ela i e alues)
a e shown in able I. Compa isons we e made using he ela i e alues o he a iables,
excep o i s me a a sal p o usion.
When compa isons a e made be ween con ol and HV g oups wi h sepa a ed male and
emale ee , esul s change ( able II). In emale hallux algus ee , he excess o leng h
a ec s only he i s me a a sal, no he hallux. In male hallux algus ee , a iables
ela ed o he leng hs o he i s me a a sal and hallux appea inc eased.
The alues o he a iables shown in able II o he male ee a e di e en om hose
o he emale ee . When hese a iables a e compa ed be ween men and women,
leng hs o he i s me a a sal and dis al phalanx o he no mal male ee a e di e en
om hose o he no mal emale ee (P < 0.01). In he HV g oup, leng hs o he dis al
phalanx and hallux o he male ee a e di e en om hose o he emale ee (P <
0.0001). These esul s a e shown in able III.
Poo - o-mode a e associa ion was ound be ween HAA and i s me a a sal p o usion (
= 0.498, p< 0.0001), i s me a a sal leng h ( = 0.443, p< 0.0001), p oximal phalanx
leng h ( = 0.383, p< 0.0001) and hallux leng h ( = 0.258, p< 0.01). O he co ela ions
show some in e es ing da a: s ong and signi ican co ela ion was ound be ween i s
me a a sal p o usion and i s me a a sal leng h ( = 0. 832, p< 0.0001), be ween
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p oximal phalanx and hallux leng hs ( = 0.814, p< 0.0001), and be ween dis al phalanx
and hallux leng hs ( = 0.759, p< 0.0001).
DISCUSSION
The au ho s conside ha he main limi a ion o his wo k is he use o wo-dimensional
images o e alua e idimensional elemen s. I has been ied o educe as a as possible
he isk o e o s ela ed wi h his aspec , ollowing a s anda dized and igo ous
adiological p o ocol. O he s udies ha e al eady demons a ed ha whene e he
adiog aphy is pe o med wi h he same p o ocol, he di e ences wi h he ac ual
si ua ion can become non-signi ican , a leas wi h ega d o he i s me a a so-digi al
segmen [6].
Di e en au ho s ha e associa ed he inc eased p o usion o he i s me a a sal o he
hallux algus de o mi y [9, 10, 13, 14]. The esul s o his s udy concu . The ange o
no mali y o he p o usion o he i s me a a sal is conside ed -2 mm o +2 mm [13,
19, 21]. Thus, acco ding o he esul s o he p esen s udy, in he ini ial phase o he
pa hology o hallux algus he e is an inc eased p o usion o he i s me a a sal (0.84
mm ± 3.02 in he con ol g oup; 3.49 mm ± 3.36 in he HV g oup). Mo eo e , we ha e
ound ha he i s me a a sal is no only u he o wa d han he second in he HV
g oup ( ela i e p o usion), bu is also longe han no mal (65.48 mm ± 4.67 in he
con ol g oup; 67.91 mm ± 4.41 in he HV g oup).
Some au ho s main ain ha in pa ien s wi h hallux algus, he leng h o he p oximal
phalanx is g ea e han in pa ien s wi hou hallux algus [22]. Con e sely, o he s udies
9
ound no di ec ela ionship be ween he leng h o his segmen and he HAA [12].
Howe e , an excessi e o al leng h o he hallux has been ela ed wi h he hallux algus
de o mi y on se e al occasions [8, 10, 18, 22]. I can also be ound au ho s who ejec
he possibili y ha a e y long hallux is ela ed wi h pa hologies such as hallux algus
[14]. The esul s o he p esen s udy show ha bo h, he p oximal phalanx o he hallux
and he g ea oe, a e longe in he hallux algus han in he no mal ee (P < 0.0001 and
P < 0.001, espec i ely) o his sample.
When compa isons be ween men and women a e made, i is obse ed ha , in he case o
he male ee , bo h he p oximal and he dis al phalanges a e longe han no mal. In he
emale ee only he p oximal phalanx is longe han no mal. The esul o his is ha
he hallux is signi ican ly longe han no mal in he men, possibly hanks o he
addi ional con ibu ion o he dis al phalanx. Howe e , in women he e is no excessi e
leng h o he hallux, because he dis al phalanx is no di e en be ween no mal and
hallux algus ee , and because he di e ence in he p oximal phalanx is lowe han in
men ee .
When he p o usion o he i s me a a sal, he leng h o he i s me a a sal, he leng h
o he p oximal phalanx o he hallux, o he o al leng h o he hallux, a e sepa a ely
analyzed, he di e ences ound be ween he con ol and HV g oups migh be conside ed
clinically insigni ican (al hough hey we e s a is ically signi ican ), as hey a e
ela i ely small di e ences. Ne e heless, he au ho s hink ha hese di e ences should
be conside ed non-isola ed. In ac , i has been obse ed a s ong, and e y signi ican
associa ion be ween he p o usion and leng h o he i s me a a sal, indica ing ha i is
e y possible ha when he p o usion o he i s me a a sal is inc eased, i s leng h is as
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Table II. Compa ison o i s me a a sal p o usion and ela i e a iables be ween
con ol and HV g oups wi h sepa a ed male and emale ee .
MALE FEET FEMALE FEET
Mean ± SD P Mean ± SD P
1MTT p o usion
Con ol
HV
0.32 ± 4.09
3.61 ± 4.04
< 0.01*
1.17 ± 2.07
3.57 ± 2.81
< 0.0001*
1MTT leng h
Con ol
HV
83.23 ± 3.00
85.94 ± 3.11
< 0.01*
84.89 ± 2.55
86.56 ± 2.89
< 0.01*
PFH leng h
Con ol
HV
41.94 ± 2.53
44.63 ± 1.76
< 0.0001*
42.12 ± 2.62
43.63 ± 2.93
< 0.05*
DFH leng h
Con ol
HV
31.77 ± 2.25
32.87 ± 1.67
< 0.05*
30.41 ± 2.45
30.28 ± 2.11
> 0.5
Hallux leng h
Con ol
HV
73.71 ± 4.00
77.51 ± 2.64
< 0.0001*
72.54 ± 3.67
73.69 ± 4.06
> 0.5

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Table III. P alues om he compa ison o he i s me a a sal p o usion and ela i e
a iables o he male and emale ee , o bo h he con ol and he HV g oup.
CONTROL
Male Fee s Female Fee
(P alues)
HALLUX VALGUS
Male Fee s Female Fee
(P alues)
1MTT p o usion 0.178 0.971
1MTT leng h 0.008* 0.446
PFH leng h 0.731 0.159
DFH leng h 0.007* < 0.0001*
Hallux leng h 0.140 < 0.0001*
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TABLE LEGENDS
TABLE I. HAA: hallux abduc us angle; 1MTT: i s me a a sal; 2MTT: second
me a a sal; PFH: p oximal phalanx o he hallux; DFH: dis al phalanx o he hallux.
Hallux do si lexion and HAA a e exp essed in deg ees. Fi s me a a sal p o usion and
absolu e a iables a e exp essed in millime e s. Rela i e a iables a e exp essed in
pe cen age o he second me a a sal leng h. * The di e ence was s a is ically
signi ican .
TABLE II. Fi s me a a sal p o usion is exp essed in millime e s. Rela i e a iables a e
exp essed in pe cen age o he second me a a sal leng h.
TABLE III. * The di e ence was s a is ically signi ican .
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Figu e 1
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Figu e 2
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Figu e 3

22
Figu e 4
23
Figu e 5
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FIGURE LEGENDS
FIGURE 1. Me hod o measu ing he ela i e me a a sal p o usion be ween he i s
and second me a a sals, acco ding o Ha dy and Clapham (1951). p: p o usion.
FIGURE 2. Me hod o measu ing he leng h o he i s and second me a a sals. A:
Dis al end o he i s me a a sal head. B: poin o in e sec ion o he longi udinal axis o
he me a a sal.
FIGURE 3. Me hod o measu ing he leng h o he p oximal phalanx o he hallux. A:
Midpoin be ween he dis al-medial and dis al-la e al ends o he phalanx head. B:
Midpoin be ween he p oximal-medial and p oximal-la e al ends o he phalanx head.
FIGURE 4. Wi h a long i s me a a so-digi al segmen , p essu e om he o e pa o
he shoe ends o de ia e he hallux la e ally. G ey a ow: p essu e om he oo wea .
FIGURE 5. P essu e on he hallux in he push-o phase in gai ends o de ia e he
hallux la e ally. G ey a ow: p essu e ecei ed by he hallux in he push-o phase o
gai .