THE MEDIAL DEVIATION OF THE FIRST METATARSAL IN THE
INCIPIENT HALLUX VALGUS DEFORMITY
AUTHORS:
Ped o V. Munue a*, Gab iel Domínguez*, Juan Polo**, Jesús Rebollo***
* G adua es in Podia ics. Lec u e s, Depa men o Podia ics. Uni e si y o Se ille.
Spain.
** Ph.D. Ma hema ics. P o esso , Depa men o Socio-Heal h Sciences. Uni e si y o
Se ille. Spain.
*** Physio he apis and Ph.D. (Uni e si y o Se ille). P o esso , Depa men o
Physio he apy. Uni e si y o Se ille. Spain.
CORRESPONDENCE:
AUTHOR: Ped o Vicen e Munue a Ma ínez
ADDRESS:
Depa amen o de Podología
Escuela Uni e si a ia de Ciencias de la Salud
C/ A icena, s/n
41009 Se illa (Spain)
TEL: 0034 95 448 65 44 ; FAX: 0034 95 448 65 46 ; E-MAIL: [email p o ec ed]
ABSTRACT
The in e me a a sal angle be ween me a a sals I and II (IMA 1-2) has been
adiog aphicaly s udied in 49 no mal ee and in 49 ee wi h a mild hallux algus (HV)
de o mi y. The aim o he s udy is o know whe he an excessi e medial de ia ion o he
i s me a a sal wi h espec o II (IMA 1-2 o e no mal alues epo ed by some
au ho s) is p esen in he ini ial phase o HV.
The esul s demons a e ha he di e ence in he mean in e me a a sal angle
be ween he wo g oups is s a is ically signi ican (8.76º in no mal ee ; 9.98º in a ec ed
ee ). Howe e , he au ho s hink i is no clinically signi ican .
O he au ho s, compa ing he IMA 1-2 in pa ien s wi h mo e ad anced HV and
wi hou HV, epo g ea e di e ences han hose ob ained in his s udy,.
The au ho s conclude ha he excessi e medial de ia ion o he i s me a a sal
is no a causal ac o , bu a consequence, in he HV de o mi y.
INTRODUCTION
Hallux algus (subsequen ly, HV) has a basic unc ional e iology, ega dless o
neu ological, auma ic, ia ogenic, and degene a i e causes, o ex e nal ac o s such as
oo wea . The basic e iology is usually a biomechanical de iciency in mo e-p oximal
join s, such as he sub ala and/o mid a sal join (Seibel 1994). Howe e , a ious
mo phological ac o s a e associa ed wi h he onse o he de o mi y. One such ac o is
he medial de ia ion o he i s me a a sal, which has been widely associa ed wi h he
HV de o mi y (Ha dy and Clapham 1951, Ha dy and Clapham 1952, Lundbe g and
Sulja 1972, Hough on and Dickson 1979, Heden and So o 1981, Kilma in e al. 1991,
Sco e al. 1991, Banks e al. 1994, Tanaka e al. 1995, Tanaka e al. 2000), some imes
as a cause, and some imes as a consequence.
The heo y ha he p ima y causal ac o in he HV de o mi y is an excessi e
medial de ia ion o he i s me a a sal is speci ically upheld by au ho s such as T uslow
(1925), Jones (1948), and Bonney and Macnab (1952). Sco e al (1991) sugges ed ha
he in e me a a sal angle be ween he i s and second me a a sals (subsequen ly, IMA
1-2) is he bes measu emen o e alua ing medial de ia ion o he i s me a a sal in
he ans e se plane. S udies such as hose o Banks e al (1994) epo low alues o
IMA 1-2 in adolescen s, indica ing ha excessi e sepa a ion be ween i s and second
me a a sals is seconda y o he de elopmen o HV. Roo e al (1977) and Michaud
(1996) also main ain ha inc eased medial de ia ion o he i s me a a sal is seconda y
o HV de elopmen , as i occu s in ad anced phases o he de o mi y. Piggo (1960)
asse s ha bo h la e al de ia ion o he i s oe and medial de ia ion o he i s
me a a sal inc ease wi h age. In he la e s udy, he high alues o IMA 1-2 obse ed in
he oldes pa ien s we e no seen in younge ones. The e o e, i seems p obable ha he
diso de is seconda y o la e al displacemen o he p oximal phalanx o he i s oe.
The aim o he p esen wo k is o in es iga e whe he an excessi e medial
de ia ion o he i s me a a sal is a p ima y e iological ac o in he de elopmen o HV
⎯ ha is, whe he i is p esen a he onse o HV. The hypo hesis o he s udy is ha in
he ini ial phase o he HV de o mi y, he medial de ia ion o he i s me a a sal (i
exis s) is among, o e y simila o, he no mal alues epo ed by o he au ho s. This
would sugges ha he de ia ion inc eases as he de o mi y ad ances.
PATIENTS AND METHODS
The s udy has included 76 indi iduals (98 ee s udied: 51 le and 47 igh ), o
whom 56 we e women and 20 men, wi h a mean age o 23.07 ± 2.64 yea s. The subjec s
we e pa ien s a ending he Clinical Podia ic Se ice a he Uni e si y o Se ille in
2004 and 2005. To ake pa in he s udy, he subjec s had o mee a se ies o condi ions:
be be ween 20 and 29 yea s o age, ne e ha e unde gone os eoa icula su ge y on he
oo , ne e ha e su e ed se ious oo auma isms, no su e om degene a i e
diseases o neu omuscula imbalances, and no p esen e iden de o mi ies o he
o e oo (apa om HV).
Two g oups we e o med: one o no mal ee (con ol g oup) and one o mild-
HV ee (HV g oup). The indi iduals o he con ol g oup, besides mee ing he
a o emen ioned condi ions, had o p esen a hallux algus angle (subsequen ly, HVA)
no exceeding 15º, and a do si lexion o he i s me a a sophalangeal join g ea e han
65º. The indi iduals o he HV g oup, besides mee ing he a o emen ioned condi ions,
had o p esen an HVA g ea e han 15º and less han 30º.
The con ol g oup comp ised 49 ee (o 43 indi iduals: 12 men and 31 women,
age 22.63 ± 2.38 yea s), o which 29 we e le and 20 igh . The HV g oup comp ised
49 ee (o 33 indi iduals: 8 men and 25 women, age 23.51 ± 2.83 yea s).
A e accep ing pa icipa ion in he s udy, he subjec was equi ed o gi e
w i en consen . Then he do si lexion o he i s me a a sophalangeal join was
measu ed. A do soplan a X- ay was made in each subjec , wi h bo h ee oge he
(B yan 2001), he beam cen ed be ween he na icula bones o bo h ee (Ho s ield
1991), wi h he ube a an inclina ion o 15º (McC ea e al. 1977) and a dis ance o 1
me e (Smi h e al. 1984, Sal zman e al. 1994).
Each X- ay was digi ised, using a scanne able o explo e images on posi i e
ilm (EPSON EXPRESSION 1680 P o®) o c ea e a digi al image. Measu emen s we e
made on he digi ised X- ays using Au oCAD® so wa e. This so wa e is used in
A chi ec u e and Enginee ing o he design o s uc u es and buildings. I s unc ions
include he measu emen o angles, o which i was used in his s udy. Fa be e al
(2005) ha e demons a ed ha he measu emen o ce ain angles on X- ays, using a
digi al sys em, is wholly alid, and imp o es in e - and in a-obse e eliabili y as
compa ed wi h he use o he analogical echnique o goniome e and pencil.
To check ha he digi isa ion p ocess did no dis o he eal size o he X- ay, a
millime e-scale ule was digi ised, and he dis ance was measu ed be ween wo
cen ime e ma ks, and be ween wo millime e ones. The esul was 10.00 and 1.00
espec i ely, con i ming ha he eal size o he o iginal image was no al e ed.
The HVA and he IMA 1-2 we e measu ed in acco d wi h he p ocedu e
desc ibed by Coughlin e al (2002). All he measu emen s we e made by he same
obse e (PVM).
To check he eliabili y o he measu emen p ocedu e, 3 ee o he con ol
g oup and 3 o he HV g oup we e chosen a andom, and he HVA and IMA 1-2 we e
measu ed h ee imes a weekly in e als. The in aclass coe icien o co ela ion was
calcula ed using he da a ob ained om his g oup o measu emen s.
To decide whe he o use a pa ame ic o non-pa ame ic con as es o
compa ison o he wo angles be ween he wo s udy g oups, he Shapi o-Wilk es was
pe o med as a check o no mali y. I s esul sugges ed ha he Mann-Whi ney U es is
he bes o use o compa ing he HVA and IMA 1-2 be ween he con ol g oup and he
HV g oup. Any alue o P lowe han 0.05 was conside ed s a is ically signi ican .
RESULTS
The alues o he HVA and IMA 1-2 ob ained o bo h he con ol and he HV
g oups a e shown in able I.
The in aclass coe icien o co ela ion o he HVA and IMA 1-2 we e 0.997
(IC 95%: lowe limi 0.989, uppe limi 1.000; P<0.0005) and 0.886 (IC 95%: lowe
limi 0.519, uppe limi 0.983; P<0.005) espec i ely. This sugges s ha he
ep oducibili y o he measu emen s is accep able (B yan e al. 2000).
The esul s o he es o no mali y a e shown in Table II. As he da a did no
ollow a no mal dis ibu ion, i was decided o use a non-pa ame ic con as es o
independen samples: he Mann-Whi ney U es .
The di e ence o he HVA and o he IMA 1-2 was s a is ically signi ican
(P<0.0005 and P<0.05, espec i ely). The alues o he mean, s anda d de ia ion,
median and ange a e shown in Table III o he HVA, and in Table IV o he IMA 1-2.
DISCUSSION
A compa a i e s udy has been made o he medial de ia ion o he i s
me a a sal be ween a g oup o ee in which he HV de o mi y was absen and ano he
g oup in which he de o mi y was p esen in he ini ial phase. In con as wi h ea lie
s udies on he opic, only subjec s aged be ween 20 and 29 yea s a e s udied in he
p esen wo k, wi h he diso de p esen in a mild o m ⎯ ha is, wi h an HVA o less
han 30º (Kelikian 1965, Me cado 1995). This excludes indi iduals who, while mee ing
he c i e ia o inclusion o he HV g oup, a e beyond he hi d decade o li e, and ha e
an HVA equal o o g ea e han 30º. As he aim o he p esen wo k is o s udy a
possible e iological ac o o he de o mi y, high alues o bo h age and HVA a e
excluded, so ha i a ia ions in no mali y a e de ec ed, hey a e no a ibu ed o he
p og ession o he HV de o mi y.
The esul s show a s a is ically signi ican di e ence in IMA 1-2 be ween he
wo g oups. The au ho s conside ha his di e ence, al hough s a is ically signi ican ,
is no clinically signi ican . Tha is, he mean alues ob ained in bo h he con ol and
HV g oups (8.76º and 9.98º, espec i ely) a e wi hin he ange o no mal alues o e ed
by mos au ho s o his angle. Ha dy and Clapham (1951) assign a ange o 0º o 17º.
Fo Lapo a e al (1974, 1994) he no mal alue o IMA 1-2 anges be ween 0º and 14º
in a ec us oo ype, and be ween 0º and 12º in an adduc us oo ype. Tachdjian (1985)
conside s his angle no mal whene e i does no exceed 10º. S eel e al (1980) o e a
wide ange, o be ween 4º and 23º, and s a e ha 90% o no mal ee ha e a alue equal
o o less han 10º. Palladino (1991), Vale o (1992), Sanne (2003), and Ma ín and
Pon ious (2004) asse ha he no mal alue o his angle should be be ween 8º and 12º
o ec us oo ype, and be ween 8º and 10º o adduc us oo ype. Sco e al (1991)
ob ained a no mali y ange o 4º o 14º in hei s udy. F om he classi ica ion o
Me cado (1995) o IMA 1-2, he alues ob ained in he p esen s udy o bo h he
con ol g oup and he HV g oup would be desc ibed as mild (be ween 8º and 10º).
Gen ili e al (1996), and B yan e al (2000) classi y alues be ween 8º and 12º as
no mal, wi hou di e en ia ing be ween ec us o adduc us oo ype.
O he wo ks, in which compa ison o IMA 1-2 in pa ien s wi h and wi hou HV
has o med pa o he in es iga ion, ha e demons a ed g ea e di e ences han hose
ound in he p esen s udy. The au ho s conside ha such indings a e he esul o bo h
he g ea e se e i y o he HV de o mi y and a highe mean age han in his s udy. These
wo ks a e summa ised in Table V. The column o IMA 1-2 shows ha alue ob ained
o he di e ence be ween he wo g oups is g ea e han ha ob ained in he p esen
wo k.
La e al de ia ion o he i s oe can cause medial de ia ion o he i s
me a a sal. T uslow (1925) denomina ed his diso de me a a sus p imus a us ⎯ ha
is, simply a medial de ia ion o he i s me a a sal esul ing in an excessi e dis ance
be ween he heads o he i s and second me a a sals. Because his de ia ion is mainly
in he ans e se plane, i would be mo e co ec o speak o me a a sus p imus
adduc us o me a a sus p imus adduc o a us (Phillips 1994). Many au ho s ha e ound
a ela ionship be ween he g ade o HV and he angle be ween he longi udinal axes o
he i s wo me a a sals (Ha dy and Clapham 1952, Hough on and Dickson 1979,
Tanaka e al. 2000). The g ound eac ion o ces ac ing on he i s oe du ing p opulsion
ha e a medial componen ha inc easingly de ia es he i s me a a sal medially as he
angle o de ia ion o he oe wi h espec o he longi udinal axis o he oo inc eases.
Bojsen-Molle (1979) calcula ed ha he medial componen o his o ce was equal o
he g ound eac ion o ce ac ing on he de ia ed i s oe, mul iplied by he angen o
he HVA.
To his mus be added he “bows ing” e ec gene a ed by he lexo hallucis
longus and ex enso hallucis longus endons, which de elop an abduc o y o ce o he
i s oe and an adduc o y one o me a a sal I which inc ease wi h he de o mi y
(abduc ion and adduc ion wi h espec o he middle sagi al plane o he body). Sande s
e al (1992) demons a ed ha in ee wi h medial de ia ion o he i s me a a sal, he e
was a co ela ion be ween he lexo momen ac ing on he i s me a a sophalangeal
join and he inc eased medial de ia ion o he i s me a a sal. Snijde s e al (1986)
pos ula ed ha as HVA inc eases, he e is an exponen ial inc ease o he abduc o
momen in he i s me a a sophalangeal join and o he adduc o momen in he i s
cuneo-me a a sal join when he lexo muscles con ac .
Snijde s e al (1986) desc ibed a biomechanical model by which he medial
de ia ion o he i s me a a sal inc eases wi h p og ession o he HV de o mi y, wi h
he lexo hallucis longus playing an impo an ole in he inc ease. This model was la e
alida ed by Sande s e al (1992) in pa ien s wi h HV. The endon o he lexo hallucis
longus passes below he i s me a a sophalangeal join , be ween he wo sesamoids,
h ough he plan a aspec o he in e sesamoid ligamen . In a no mal oo , he e ical
axis o he me a a sophalangeal join passes di ec ly h ough his endon, such ha when
he muscle con ac s, he di ec pos e io o ce p oduces plan a s abilisa ion o he
hallux and comp ession in he join . In HV ee , wi h he sesamoids displaced la e ally,
he e ical axis, a ound which he mo emen in he ans e se plane is p oduced, alls
medially o he lexo hallucis longus endon (Figu e 1). This gene a es a le e e ec ,
which does no no mally exis , be ween his endon and he e ical axis (double-headed
a ow “A”). The combina ion o he o ce p oduced by con ac ion o he lexo hallucis
longus (a ow “C”) and ha p oduced by ic ion o ce o he i s oe wi h he g ound
(a ow “B”) gene a es a ec o o o ce pos e io ly, pa allel o he longi udinal axis o
he de ia ed p oximal phalanx (a ow “D”). To achie e a balance o o ces in he
ans e se plane, a esis ance is gene a ed in he i s cuneo-me a a sal join , equi alen
o a ec o o o ce equal in magni ude o ha exe cised by he i s oe agains he
me a a sal, bu in he opposi e di ec ion (a ow “E”). This pai o o ces p oduces an
an i-clockwise o a ional momen ha ends o de ia e he i s me a a sal in adduc ion
(s iped a ow).
The dis ancing o he lexo hallucis longus endon om he head o he i s
me a a sal has a g ea e e ec han ha o he ex enso hallucis longus endon (Lamu e
al. 1996). The ex enso hallucis longus con ibu es o he de elopmen o HV only when
his is e y ad anced (Phillips 1994). A s udy ca ied ou by Lamu e al (1996)
co obo a es his, and also alida es he model o Snijde s e al (1986). Lamu e al
(1996) de e mined he posi ion and he le e a m o he ex enso hallucis longus and
lexo hallucis longus endons in ela ion o he abduc ion o he hallux and he
adduc ion o he i s me a a sal, and obse ed ha he HVA inc eased wi h dis ance o
Table I.
HVA and IMA 1-2 alues o he subjec s o bo h he con ol and HV g oups.
Con ol g oup
(n = 49) HV g oup
(n = 49)
Ob ained
alues
(deg ees)
Numbe o
subjec s
Ob ained
alues
(deg ees)
Numbe o
subjec s
4 3 16 9
6 2 17 4
7 2 18 5
8 6 19 1
9 6 20 7
10 3 21 4
11 9 22 4
12 4 23 3
13 2 24 3
14 7 25 4
15 5 26 3
- 28 1
HVA
- 29 1
4 1 4 1
5 2 5 1
6 2 6 3
7 6 7 2
8 6 8 6
9 15 9 7
10 12 10 8
11 3 11 7
12 1 12 9
13 1 13 2
- 15 2
IMA 1-2
- 16 1
Table II.
Shapi o-Wilk es o HVA and IMA 1-2 o he con ol g oup and he HV g oup
Shapi o-Wilk
HVA
Con ol g oup 0.031
HV g oup 0.009
IMA 1-2
Con ol g oup 0.023
HV g oup 0.417
Table III.
Compa ison o HVA be ween he con ol g oup and he HV g oup
HVA Con ol g oup
(n = 49)
(deg ees)
HV g oup
(n = 49)
(deg ees)
Median 11 20
Range 4-15 16-29
Mean 10.53 20.59
S anda d de ia ion 3.08 3.63
Signi icance (P) 0.000
Table IV.
Compa ison o IMA 1-2 be ween he con ol g oup and he HV g oup
HVA Con ol g oup
(n = 49)
(deg ees)
HV g oup
(n = 49)
(deg ees)
Median 9 10
Range 4-13 4-16
Mean 8.76 9.98
S anda d de ia ion 1.77 2.52
Signi icance (P) 0.006
Table V.
A compa ison o IMA 1-2 be ween con ol g oup and HV g oup om s udies pe o med
by a ious au ho s.
Au ho s G oup Sample size Age
(yea s)
HVA
(mean ± SD)
IMA 1-2
(mean ± SD)
Ha dy and
Clapham (1951)
Con ol
HV
252 ee
165 ee
16-65
20-66
15.7º
32º
8.5º
13º
Hough on and
Dickson (1979)
Con ol
HV
30 ee
75 ee
“adul s”
23
16.7 ± 1.3º
30 ± 7.2º
9.5 ± 2.2º
13.6 ± 3.3º
Heden and So o
(1981)
Con ol
HV
100 X- ays
200 X- ays
-
-
12.27 ± 5.4
26.54 ± 10.36
8.12 ± 2.2
12.21 ± 3.45
Sco e al (1991) Con ol
HV
100 ee
100 ee
47
44
13º
32º
3º
13º
Tanaka e al
(1995)
Con ol
HV
94 ee
177 ee
41
44
9.7 ± 4.6º
30.2 ± 9.3º
9.8 ± 2.0º
15 ± 3.1º
Talbo and
Sal zman (1997)
Con ol
HV
30 pa ien s
39 pa ien s
41
42
12 ± 5.1º
30.2 ± 11.1º
9.1 ± 2.0º
15 ± 5.3º
B yan e al (2000) Con ol
HV
30 pa ien s
30 pa ien s
39.8
51.3
10.3 ± 4.0º
26.3 ± 6.3º
9.4 ± 1.9º
13 ± 3.0º
Tanaka e al
(2000)
Con ol
HV
94 ee
229 ee
-
-
9.7 ± 4.6º
29.4 ± 9.0º
9.8 ± 2.0º
14.9 ± 3.1º
Tho da son and
K ewe (2002)
Con ol
HV
50 ee
50 ee
-
-
6.5º
27.9º
8.8º
11.4º
G ebing and
Coughlin (2004)
Con ol
HV
43 pa ien s
43 pa ien s
46
53
10.6º
34.6º
8.1º
15.4º
King and Toolan
(2004)
Con ol
HV
15 pa ien s
25 pa ien s
36
48
14 ± 4º
36 ± 9º
8 ± 2º
15 ± 3º
Flexo hallucis longus endon
me a a sophalangeal
join e ical axis
A
C
B
D
E
Figu e 1.
Model explaining how he medial de ia ion o me a a sal I is seconda y o p og ession
o he HV de o mi y. Model adap ed om Snijde s CJ, Snijde JG, Philippens MM.
Biomechanics o Hallux Valgus and Sp ead Foo . Foo Ankle 1986; 7: 26-39.
