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Arch Index: An Easier Approach for Arch Height (A Regression Analysis)

Authors:
  • Institute of Post Graduate Medical Education & Research Kolkata

Abstract

Background: Arch-height estimation though practiced usually in supine posture; is neither correct nor scientific as referred in literature, which favour for standing x-rays or arch-index as yardstick. In fact the standing x-rays can be excused for being troublesome in busy OPD, but an ink-footprint on simple graph-sheet can be documented, as it is easier, cheaper and requires almost no machineries and expertisation. Objective: So this study aimed to redefine the inter-relationship of the radiological standing arch-heights with the arch-index for correlation and regression so that from the later we can derive the radiographical standing arch-height values indirectly, avoiding the actual maneuver. Methods: The study involved 103 adult subjects attending at a tertiary care hospital of North Bengal. From the standing x-rays of foot, the standing navicular, talar heights were measured, and ‘normalised’ with the foot length. In parallel foot-prints also been obtained for arch-index. Finally variables analysed by SPSS software. Result: The arch-index showed significant negative correlations and simple linear regressions with standing navicular height, standing talar height as well as standing normalised navicular and talar heights analysed in both sexes separately with supporting mathematical equations. Conclusion: To measure the standing arch-height in a busy OPD, it is wise to have the foot-print first. Arch-index once get known, can be put in the equations as derived here, to predict the preferred standing arch-heights in either sex.
© 2012. Al Ameen Charitable Fund Trust, Bangalore
137
A J M S
Al A me en J M ed S ci ( 20 12 ) 5 ( 2 ) : 1 3 7 - 1 4 6
(A US National Library of Medicine enlisted journal)
I SS N 0 9 74 - 11 4 3
C O DE N : A AJ M BG
O RIGINAL ARTICLE
Arch Index: An Easier Approach for Arch Height
(A Regression Analysis)
Hironmoy Roy
1*
, Kalyan Bhattacharya
2
, Samar Deb
3
and Kuntala Ray
4
1
Department of Anatomy, North Bengal Medical College & Hospital, Sushrutanagar;
Darjeeling, West Bengal, India,
2
Department of Anatomy, College of Medicine and
JNM Hospital, WBUHS, Kalyani; Nadia, West Bengal, India,
3
Principal, Katihar
Medical College, Bihar, India and
4
Department of Community Medicine, North
Bengal Medical College & Hospital, Sushrutanagar; Darjeeling, West Bengal, India
Abstract: Background: Arch-height estimation though practiced usually in supine posture; is
neither correct nor scientific as referred in literature, which favour for standing x-rays or arch-
index as yardstick. In fact the standing x-rays can be excused for being troublesome in busy
OPD, but an ink-footprint on simple graph-sheet can be documented, as it is easier, cheaper
and requires almost no machineries and expertisation. Objective: So this study aimed to
redefine the inter-relationship of the radiological standing arch-heights with the arch-index
for correlation and regression so that from the later we can derive the radiographical standing
arch-height values indirectly, avoiding the actual maneuver. Methods: The study involved
103 adult subjects attending at a tertiary care hospital of North Bengal. From the standing x-
rays of foot, the standing navicular, talar heights were measured, and ‘normalised’ with the
foot length. In parallel foot-prints also been obtained for arch-index. Finally variables
analysed by SPSS software. Result: The arch-index showed significant negative correlations
and simple linear regressions with standing navicular height, standing talar height as well as
standing normalised navicular and talar heights analysed in both sexes separately with
supporting mathematical equations. Conclusion: To measure the standing arch-height in a
busy OPD, it is wise to have the foot-print first. Arch-index once get known, can be put in the
equations as derived here, to predict the preferred standing arch-heights in either sex.
Key words: Arch-Index, Arch of Foot, Arch-height
Introduction
Measurement of the height of the arch of foot deserves immense importance so far its
clinical aspects are concerned and for this purpose since middle of the past century
several methods were used by pioneer researchers. Practically the height of the
medial longitudinal arch provides acceptable outlook of the arch-height. Some
researchers have classified the foot arch type by only visual impression, which was
quite practiced till the end of last century [1-3]. On the other hand a few of them
carried on such a classification based on palpation of the navicular tuberosity [4]. In
late nineties researchers approached with the help of radiography in parallel with
footprint. Radiographically parameters like the ‘talar height’ , ‘navicular height’ and
recently the ‘normalised navicular height’ obtained from standing weight bearing
lateral view x-ray of foot, were accepted as yardsticks to predict the arch height [5-8].
Al Ameen J Med Sci; Volume 5, No.2, 2012 Roy H et al
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138
Procurement of, and processing the footprint being easier and cheaper, is more
acceptable for the patient than radiography. Hence, in spite of the fact that
radiography is still important in establishing the arch height, footprint procedures are
preferred to it [9-10]. It was previously disclosed that the foot-print obtained on a
graph sheet by conventional ink is better that the electronic foot-print obtained by
special soft-ware system, so far determination of the sole contact area was concerned
[11].
This can be conveniently taken on a graph paper and the Arch Index can be
calculated thereafter to ascertain the height of the arch of foot. The concept of Arch
Index was first described by Cavanagah et al. (1987) as the ratio of the area of the
middle third of the foot to the entire foot area excluding the toes. An arch index of
less than 0.21 has been said to be indicative of a cavus foot, while it greater than 0.26
is indicative of planus foot whereas Arch Index between 0.21~0.26 corroborates
normal arch height. Importance of “arch-index” as a sensitive podographic indicator
was later on confirmed in different studies. [12] Later it has been
established the
Arch Index, derived from footprint to show a significant negative correlation with the
navicular height [8, 13-15]. But unfortunately almost no studies have inter-related
mathematically the foot-print derived arch-index values with the radiographically
evaluated standing arch-height measurements with an acceptable equation, by which
one can interpret directly the standing navicular or talar height with the help of arch
index without proceeding through actual maneuver. Especially such information
lacks in pertinent literature so far in Indian population is concerned.
Objective: This study is based on the question that whether the value of the arch-
index, once determined; can predict the standing navicular height, standing talar
height as well as their respective ‘normalised’ values of an individual?
Material and Methods
This descriptive epidemiological study was carried out in the Out-patient Department
of Radio-diagnosis (Radio-diagnosis OPD) of North Bengal Medical College, within
the period of one year with the proper permission from (a) the institutional Ethical
Committee; (b) Principal of the medical college and (c) the Heads of the concerned
departments. The Radiology OPD was visited twice a week. Patients and their
attendants, waiting there, who were found having no obvious vivid deformity of
lower-limb and apparently not seriously sick; were approached randomly and thus
initially 140 adult persons were approached. Detailed history was taken to exclude
any previous operations, injuries or diseases of lower limb, vertebral column as well
as in sole and thus 125 were short listed. Among them finally 103 subjects have put
their informed consent to be included in the study.
X-rays of their left foot were obtained in standing position with both legs straight
keeping aside to bear the body weight equally, as referred in literature [16-17]. From
each set of X-ray film ‘height of the talar dome’ (henceforth mentioned as Talar
Height); ‘height of the navicular tuberosity’ (henceforth mentioned as Navicular
Height) and the ‘truncated foot length’ (henceforth mentioned as Foot length) were
measured.
Al Ameen J Med Sci; Volume 5, No.2, 2012 Roy H et al
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The ‘truncated foot length’ (FL) was
determined by the distance of posterior
calcanean tuberosity to the head of the
first metatarsal excluding the
phalanges. (Fig.1)
After that, a washable inkpad was
rubbed on the plantar aspect of the
subject’s left foot and he/she was
instructed to stand in same posture
followed during x-ray, on a cm-
calibrated graph-sheet provided; so that
it totally covers his/her left foot. Thus
the standard imprint of the weight-
bearing left foot was taken, which was
considered to be the foot-print of a 50%
body-weight bearing foot (the other
50% of the body weight was borne by
the right foot, whose print was not
taken).
Following the description in literature
in the footprint, the linear distance of
the centre of the heel (say the point K)
and the tip of the second toe (axis of the
foot) (say the point J) was measured.
Next perpendicular line was drawn
tangential to most anterior point of the
main body of the foot print. Their point
of intersection was marked (say the
point L). Next the line LK was divided
in equal three parts. Ultimately the main
body of the footprint was divided in
three areas from those points with the
perpendiculars from the foot axis. The
anterior, middle and posterior areas
were marked as A, B, C respectively.
Their areas were determined (in sq.cm).
Arch Index = B ÷ [A+B+C]. (Fig.2)
[12]
Values were put for statistical analysis in SPSS version 12.0 software for required
analysis. Prediction of significant relationship amongst the pair of variables was
determined by the “Correlation coefficient” i.e. Pearson’s ‘r’ or Spearman’s rank
‘rho’ depending on their distribution [18].
Fig-1: The below skiagram of foot depicts
the measurement of navicular height (NH),
Talar height (TH) and truncated foot length
(FL) in standing posture.
Fig-2: The below photograph of left foot-
print illustrates the estimation of the arch
index from a footprint of an individual
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Relation of changes of a dependent variable (say, y) with an independent variable
(say, x) was ascertained by simple linear regression, with the “Regression coefficient
(say, b)” and “Regression constant (say a)”; where the model of the regression
equation was y = a + bx .Again as in every equation; 95% confidence interval (
1.96 standard deviation) was accepted and “standard error of regression (STE )” was
considered, Then the final equation model becomes y = (a+ bx) ± (1.96 x STE ) [18].
Results
Among 103 adult subjects, we could include 90 (87.4%) male and 13 (12.6%)
females. Since the foot-architecture of a man and woman are not same anatomically
and gait of a man differs from that of a woman, so all the results have been grouped
sex-wise for further prediction. The mean-values of the standing navicular and talar
heights were found as 3.52 ±0.79 cm and 7.74 ±0.60 cm in males and the same for
females as 3.07 ±0.34 cm and 7.31 ±0.27 cm respectively. Later those parameters
were normalised to the standing foot length of individual to obtain their ‘standing
normalised’ navicular and talar heights, which were documented with mean of 3.52
±0.79 in males and 3.07± 0.34 in females.
Values of Arch Indices in respective sex-group were also calculated out to be
finalized with mean of 0.22 ±0.04 and 0.23 ±0.03 among males and females.
Following the classification-system as described by McCroy et al.(1997) [14]
based
on the arch index, in the present population 59.8% had normal arch, whereas 35.3%
and 4.9% had high and flat arches respectively.
In both the groups the arch-index noted to bear significant negative correlation
(Correlation coefficient -0.74 with p=0.000, and -0.75 with p=0.000) with the
absolute value of standing navicular height (NHSTD).So naturally, regression was
continued in each group an resultant equations could be derived as follow-
In males: NHSTD = [6.98 – 15.97 x Arch Index] ± 1.04
In females: NHSTD = [5.1 – 8.99 x Arch Index] ± 0.49 (Table -1, Fig. 3)
Table-1: Estimation of standing navicular height (NHSTD) from Arch Index in both sexes
Male n =90 Female n= 13
Arch Index NHSTD Arch Index NHSTD
Mean 0.22 3.52 0.23 3.07
Std. Devn. 0.04 0.79 0.03 0.34
Correlation
coefficient
- 0.74
(p= 0.000)
-0.75
(p= 0.006)
Regression
coefficient
-15.97
(p= 0.000)
-8.99
(p= 0.006)
Regression constant 6.98 5.1
Std. Error of Estimate 0.53 0.25
Wald statistics
( F value)
106.88
(p=0.000)
11.51
(p= 0.006)
Independent variable: Arch Index
Dependent variable: Standing navicular height (NHSTD)
The above table represents the correlation and regression of Arch Index to NHSTD in both the sexes
Al Ameen J Med Sci; Volume 5, No.2, 2012 Roy H et al
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141
Fig-3: Scatter plot showing
regression amongst Arch
Index and NHSTD in either
sex.
The graph represents the
prediction of NHSTD from
Arch Index in male and female
subjects.
Similar trend also noted for ‘standing normalised navicular height (NNHSTD)’, with
which arch-index maintained correlation -0.62 (p=0.000) and -0.81(p=0.001) in male
and female groups respectively. Further analysis here also produced equations for
simple linear regression as:
In males: NNHSTD = [0.29 – 0.55 x Arch Index] ± 0.06
In females: NNHSTD = [0.34 – 0.82 x Arch Index] ± 0.04 (Table -2, Fig. 4)
Table-2: Estimation of standing normalised navicular height (NNHSTD) from Arch Index
in both sexes
Male n =90 Female n= 13
Arch Index NNHSTD Arch Index NNHSTD
Mean 0.22 0.17 0.23 0.16
Std. Devn. 0.04 0.03 0.03 0.03
Correlation
coefficient
- 0.62
(p= 0.000)
- 0.81
(p= 0.001)
Regression
coefficient
- 0.55
(p= 0.000)
- 0.82
(p= 0.003)
Regression constant 0.29 0.34
Std. Error of Estimate 0.03 0.02
Wald statistics
( F value)
54.13
(p=0.000)
20.49
(p= 0.001)
Independent variable: Arch Index
Dependent variable: Standing normalised navicular height (NNHSTD)
The above table represents the correlation and regression of Arch Index to NNHSTD in both the
sexes
Al Ameen J Med Sci; Volume 5, No.2, 2012 Roy H et al
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142
Fig-4: Scatter plot of
regression amongst Arch Index
and NNHSTD either sex.
The graph represents the
regression between the arch-
index and standing normalised
navicular height in both males
and females.
The graph represents the
prediction of NHSTD from
Arch Index female subjects.
Alike that significant negative correlation also could be documented for the
dependence of standing talar height (THSTD) on arch-index of an individual, as
studied in both the sex-groups (Coefficients as -0.82 with p=0.000 and -0.61 with
p=0.028 in males and females respectively). Simple linear regression later on again
revealed the equations as follows:
In males: THSTD = [10.63 – 13.35 x Arch Index] ± 0.67
In females: THSTD = [9.09 – 9.14 x Arch Index] ± 0.65 (Table -3, Fig. 5)
Table-3: Estimation of standing talar height (THSTD) from Arch Index in both sexes
Male n =90 Female n= 13
Arch Index THSTD Arch Index THSTD
Mean 0.22 7.74 0.23 7.02
Std. Devn. 0.04 0.59 0.03 0.40
Correlation
coefficient
-0.82
(p= 0.000)
-0.61
(p= 0.028)
Regression
coefficient
-13.35
(p= 0.000)
-9.14
(p= 0.028)
Regression constant 10.63 9.09
Std. Error of Estimate 0.34 0.33
Wald statistics
( F value)
186.76
(p=0.000)
6.45
(p= 0.028)
Independent variable: Arch Index
Dependent variable: Standing talar height (THSTD)
The above table represents the correlation and regression of Arch Index to THSTD in both the sexes
Al Ameen J Med Sci; Volume 5, No.2, 2012 Roy H et al
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143
Fig-5: Scatter plot of
correlation of Arch Index and
THSTD both sexes.
The graph represents the
prediction of THSTD from
Arch Index in both male and
females.
Dependency of the ‘normalised talar height in standing (NTHSTD)’ was also
confirmed with the arch-index as studied group-wise with correlation coefficient -
0.38/p=0.000 and -0.81/p=0.001 in males and females respectively. Like before, here
also regression study has affirmed the equations of simple linear model as:
In males: NTHSTD = [0.43 – 0.21 x Arch Index] ± 0.37
In females: NTHSTD = [0.65 – 1.27 x Arch Index] ± 0.04 (Table -4, Fig. 6)
Table-4: Estimation of standing normalised talar height (NTHSTD) from Arch Index in both
sexes
Male n =90 Female n= 13
Arch Index NTHSTD Arch Index NTHSTD
Mean 0.22 0.39 0.23 0.36
Std. Devn. 0.04 0.02 0.03 0.04
Correlation
coefficient
- 0.38
(p= 0.000)
-0.81
(p= 0.001)
Regression
coefficient
- 0.21
(p= 0.009)
-1.27
(p= 0.001)
Regression constant 0.43 0.65
Std. Error of Estimate 0.19 0.02
Wald statistics
( F value)
14.13
(p=0.000)
20.92
(p= 0.001)
Independent variable: Arch Index
Dependent variable: Standing normalised talar height (NTHSTD)
The above table represents the correlation and regression of Arch Index to NTHSTD in both the sexes
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Fig-6: Scatter plot of
regression amongst Arch
Index and NTHSTD in both
sexes.
The graph represents the
regression between Arch Index
and NTHSTD in both males
and females.
Discussion
Essence of this study was to reveal an easier way to derive the standing arch-height
of an individual usable in day-to-day clinical practice bypassing the so called
troublesome maneuvers; so that it becomes feasible for a clinician to get the idea of
actual standing arch-height indirectly from the method adoptable OPD, which has
been successfully achieved by the regression equations enlisted above. Foot being a
bilateral structure of our body, throughout this study all x-rays have been taken for
the left-foot of the subjects for universal representation. As a byproduct, this study
could interpret the arch-height parameters in both the sex groups and establish the
regression equations separately. Though this study had a considerable number of
male participants, but it is true that this it could not include sufficient female
subjects, which is essentially for the lack of awareness, privacy and female
technicians in the limited infrastructure; but still it gives an impression of arch-height
parameters in both the sex groups strengthening the result and outcome.
The values of the absolute standing navicular height, standing talar height as well as
those of ‘normalised’ standing navicular and talar heights and even the arch-index, as
studied here no doubt corroborate earlier studies [6-8, 19-25]. But documentation of
‘standing normalised talar height’ was not found in any literature as searched for. In
addition this study also documented slight gender preponderance of the standing
arch-heights values in male than in females. In this issue earlier studies could not
reach any common conclusion definitely [26-29]. So far the values of arch-indices
are concerned, though almost 60% of the study population has normal arch, but
nearly 36% has higher arches, which might be for their habitat in foothill areas.
Al Ameen J Med Sci; Volume 5, No.2, 2012 Roy H et al
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145
The standing navicular height (NHSTD), talar height (THSTD) and normalised
navicular height (NNHSTD) along with normalised talar height (NTHSTD)
individually has been correlated with the arch-index at the margin of statistical
significance. Findings of majorities of previous studies were same with the present
one [8, 12, 14, 15, and 21]. But it is very much unfortunate that derivation of
regression equations enlightening the dependence of each factors on arch-index,
which has been vividly discussed in this study, found nowhere in persistent literature
as searched for. So naturally it would be the first attempt for doing such.
Conclusion
Since arch-index is a time-tested reliable parameter for estimation of arch height so
itself can be used regularly for measuring such. Radiographical arch-height
estimation though preferred by clinicians, but usually approached in a wrong way to
measure it in supine posture in stead of measuring it in standing posture because of
heavy crowd with limited radiological machineries and expertisation. This study
confirms with the fact that without going in the unnecessary time-taking radiological
procedures, it is better to have the foot-print of the subject to analyse the arch-index,
from which standing arch-height values easily can be calculated.
Acknowledgement
A grateful acknowledgement should to be paid to the Chairman of the institutional
Ethical Committee, the respected Principal and the other faculties of the Department
of Anatomy as well as Department of Radiodiagnosis of the North Bengal Medical
College. Sincere gratitude to be paid to Prof. S.P.Kabiraj, Dr. Subhra Mondal and Dr.
Shibshankar Banerjee for their kind help, guidance, and support to conduct this
study.
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*All correspondences to: Dr. Hironmoy Roy, Department of Anatomy, North Bengal Medical College
Sushrutanagar, Siliguri. Dist: Darjeeling-734012 West Bengal, India. E-mail: hironmoy19@gmail.com
... The participant had no neuromuscular disease or biomechanical abnormalities other than the flatfoot. In this study, the navicular drop test [28] and footprint index [29] were used to classify the foot type. Flatfoot is characterized by a high navicular drop (>10 mm) and footprint index (>0.26) ...
... Flatfoot is characterized by a high navicular drop (>10 mm) and footprint index (>0.26) [28,29]. The participant's right foot was recognized as flatfoot with an arch index of 0.30 and a navicular drop of 12 mm. ...
Article
Background Different arch support heights of the customized foot orthosis could produce different effects on the internal biomechanics of the foot. However, quantitative evidence is scarce. Therefore, we aimed to investigate and quantify the influence of arch support heights on the internal foot biomechanics during walking stance. Methods We reconstructed a foot finite element model from a volunteer with flexible flatfoot. The model enabled a three-dimensional representation of the plantar fascia and its interactions with surrounding osteotendinous structures. The volunteer walked in foot orthosis with different arch heights (low, neutral, and high). Muscle forces during gaits were calculated by a multibody model and used to drive a foot finite element model. The foot contact pressures and plantar fascia strains in different regions were compared among the insole conditions at the first and second vertical ground reaction force (VGRF) peak and VGRF valley instants. Results The results indicated that peak foot pressures decreased in balanced standing and second VGRF as the arch support height increased. However, peak midfoot pressures increased during all simulated instants. Meanwhile, high arch support decreased the plantar fascia loading by 5% to 15.4 % in proximal regions but increased in the middle and distal regions. Conclusion Although arch support could generally decrease the plantar foot pressure and plantar fascia loading, the excessive arch height may induce high midfoot pressure and loadings at the central portion of the plantar fascia. The consideration of fascia-soft tissue interaction in modeling could improve the prediction of plantar fascia strains towards design optimization for orthoses.
... A young male adult (27 years old, 175 cm height, and 64 kg weight) with flatfoot participated in this study. This study utilized the footprint index [19] and the navicular drop test [20] to identify the foot type. For flatfoot, the footprint index is more than 0.26, and navicular drop is more than 10 mm [19,20]. ...
... This study utilized the footprint index [19] and the navicular drop test [20] to identify the foot type. For flatfoot, the footprint index is more than 0.26, and navicular drop is more than 10 mm [19,20]. The arch index and the navicular drop of the subject's right foot are 0.30 and 12 mm, respectively, which was recognized as a flatfoot case. ...
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The finite element (FE) method has been widely used to investigate the internal force of plantar fascia, which could reveal the relationship between plantar fascia dysfunction and flatfoot deformity during weight-bearing conditions. However, for most foot FE models, plantar fascia utilized truss elements or three-dimensional geometry that did not consider the interaction between plantar fascia and bulk soft tissue. These configurations could ignore the impact of superoinferior loading induced by arch support and underestimate the plantar fascia loading. This study aims to investigate how the fascia-bulk soft tissue interaction affects the internal foot biomechanics in the flatfoot FE analysis with a three-dimensional plantar fascia model, which included both fascia-bone and fascia-bulk soft tissue interactions (3DBPT1). To evaluate the effect of fascia-bulk soft tissue interaction on internal foot mechanics, this study compared the 3DBPT model with the other two plantar fascia models, including linear fascia (BPL2) and three-dimensional plantar fascia without fascia-bulk soft tissue interaction (3DBP3). The predicted foot contact pressure in the 3DBPT model was compared with the measured value obtained by the F-Scan pressure measurement system in balanced standing. Peak von Mises stresses in the plantar fascia and foot ligaments were reported. The stress of the plantar fascia in the 3DBPT model was higher than that of 3DBP. In the 3DBPT model, the superoinferior loading exerted on the bulk soft tissue could be directly transferred to the plantar fascia. The proposed model, including the plantar fascia and bulk soft tissue interaction, could reveal relatively reliable plantar fascia loading in flatfoot deformity, thereby contributing to the development of orthotic designs for the flatfoot deformity.
... The plantar region was classified into rearfoot, midfoot, forefoot, and toe areas, with contact areas of rearfoot, midfoot, and forefoot used in this study. Arch index for the right and left limb was calculated using Equation (1) as per previously published protocol [4,20]. ...
... The main finding of this study was that the arch index increased greatly from static weight-bearing standing to dynamic walking and running conditions but showed good symmetry between left and right feet during walking and running tasks, which are supported by our hypothesis. Arch index based on footprint has been proven to as an effective method to reflect the arch height [20]. However, the body composition could be a confounding factor while calculating the arch index based on footprint. ...
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The purpose of this study was to investigate the variations of arch index from static standing to dynamic walking and running; furthermore, the interlimb symmetry was checked in the two populations. A total of eighty male participants were recruited for this study, with forty habitually barefoot and forty habitually shod males, respectively. Arch index (AI) was calculated following the previously established “gold standard” measurement via contact areas recorded from EMED. Repeated measure analysis of variance (ANOVA) was employed to compare the difference between static and dynamic walking and running arch index. Paired-samples t-test and symmetry index (SI) were used to investigate the symmetry of the left foot arch index and right foot arch index. It was found that the dynamic arch index was significantly higher than the static arch index in barefoot and shod males, showing an increase from static weight-bearing standing to dynamic walking and running. However, interlimb (right-left) symmetry in the foot arch index was observed in the two populations. Dynamic changes of the arch index may provide implications that need to be considered while designing shoe lasts or insoles. Knowledge of the healthy arch index range reported from this study could also be used as a standard baseline to probe into foot and arch disorders.
... Previous studies adopted many methods to categorize the foot posture [29]. In this study, an ink-footprint method [30] was used as it is reliable, cheap, easy, and requires almost no expertise. The foot posture of each participant was evaluated by measuring the Harris mat footprint during half weightbearing [31]. ...
... The foot posture of each participant was evaluated by measuring the Harris mat footprint during half weightbearing [31]. The inclusion criteria were (1) an arch index of ≥ 0.28 for both feet [30], (2) 18 to 25 years old, and (3) not overweight (BMI > 30 kg·m −2 ). The exclusion criteria included (1) neuromuscular disease, (2) biomechanical abnormalities other than flatfoot and complications affecting walking ability and performance, and (3) foot orthoses use or physiotherapy in the last 6 months. ...
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Flatfoot is linked to secondary lower limb joint problems, such as patellofemoral pain. This study aimed to investigate the influence of medial posting insoles on the joint mechanics of the lower extremity in adults with flatfoot. Gait analysis was performed on fifteen young adults with flatfoot under two conditions: walking with shoes and foot orthoses (WSFO), and walking with shoes (WS) in random order. The data collected by a vicon system were used to drive the musculoskeletal model to estimate the hip, patellofemoral, ankle, medial and lateral tibiofemoral joint contact forces. The joint contact forces in WSFO and WS conditions were compared. Compared to the WS group, the second peak patellofemoral contact force (p < 0.05) and the peak ankle contact force (p < 0.05) were significantly lower in the WSFO group by 10.2% and 6.8%, respectively. The foot orthosis significantly reduced the peak ankle eversion angle (p < 0.05) and ankle eversion moment (p < 0.05); however, the peak knee adduction moment increased (p < 0.05). The reduction in the patellofemoral joint force and ankle contact force could potentially inhibit flatfoot-induced lower limb joint problems, despite a greater knee adduction moment.
... Descriptive 12 showed significant negative correlations and simple linear regressions with standing navicular height, standing talar height as well as standing normalized navicular and talar heights in the arch-index analyzed in both sexes separately with supporting mathematical equations. Shiang T (1998) 2 showed a better correlation between the footprint value measurements and the normalized navicular height. ...
... Navicular method of MLA assessment -0.297 & -0.104 with statistical significance of <0.05 for right and no significance for left foot. Although a positive lower level of correlation between Navicular height and MFPA 0.435 and 0.461 for right and left foot was identified with statistical significance of <0.005.Roy (2012) ...
... A young male adult of age 28, height 175 cm and mass 62.5 kg with flexible flatfoot was involved. The footprint index [25] and the navicular drop test [26] were used to determine the foot type. The participant's right foot was classified as flatfoot, with a large arch index ( > 0.26) and a large navicular drop ( > 10 mm) [ 25 , 26 ]. ...
Article
Background and Objective Mid/hindfoot arthrodesis could modify the misalignment of adult-acquired flatfoot and attenuate pain. However, the long-term biomechanical effects of these surgical procedures remain unclear, and the quantitative evidence is scarce. Therefore, we aimed to investigate and quantify the influences of five mid/hindfoot arthrodeses on the internal foot biomechanics during walking stance. Methods A young participant with flexible flatfoot was recruited for this study. We reconstructed a subject-specific musculoskeletal multibody driven-finite element (FE) foot model based on the foot magnetic resonance imaging. The severe flatfoot model was developed from the flexible flatfoot through the attenuation of ligaments and the unloading of the posterior tibial muscle. The five mid/hindfoot arthrodeses simulations (subtalar, talonavicular, calcaneocuboid, double, and triple arthrodeses) and a control condition (no arthrodesis) were performed simultaneously in the detailed foot multibody dynamics model and FE model. Muscle forces calculated by a detailed multi-segment foot model and ground reaction force were used to drive the foot FE model. The internal foot loadings were compared among control and these arthrodeses conditions at the first and second vertical ground reaction force (VGRF) peak and VGRF valley instants. Results The results indicated that the navicular heights in double and triple arthrodeses were higher than other surgical procedures, while the subtalar arthrodesis had the smallest values. Five mid/hindfoot arthrodeses reduced the peak plantar fascia stress compared to control. However, double and triple arthrodeses increased the peak medial cuneo-navicular joint contact pressures and peak foot pressures as well as the metatarsal bones stresses. Conclusion Although mid/hindfoot arthrodesis generally reduced the collapse of medial longitudinal arch and plantar fascia loading during the stance phase, the increased loading in the adjacent unfused joint and metatarsal bones for double and triple arthrodeses should be noted. These findings could account for some symptoms experienced by flatfoot patients after surgery, which may facilitate the optimization of surgical protocols.
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Research on the plantar segment has not been widely carried out in Indonesia’s population, even though the plantar segment data will be essential in further research and therapy of plantar-related problems. Therefore, this research intends to describe the plantar profile: the foot arch and the plantar pressure difference between the right and left foot. This research applied a cross-sectional study. Subjects were recruited from the Faculty of Medicine students, Universitas Indonesia, class 2012, with inclusion criteria aged 17-21 years and normal gait. Meanwhile, the exclusion criteria consisted of having postural abnormalities, a history of neuromusculoskeletal disorders in the lower limbs, a history of fractures in the spine and legs, a history of surgery on the spine and legs, and refusing to participate in the study. Research subjects stood on a plantar scanner, conducted at the Anatomy Laboratory, the Faculty of Medicine, Universitas Indonesia. The Mann-Whitney test was then used to analyze the difference in plantar pressure between the right and left foot. The results revealed that a hundred research subjects had a proportion of a low foot arch of 4%, a normal foot arch of 89%, and a high foot arch of 7%. The median right plantar pressure was 273.5 KPa, while the median left plantar pressure was 253.5 KPa. The Mann-Whitney test showed a p-value of 0.954 for the pressure difference between right and left foot. There was no plantar pressure difference between the right and left foot.
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Introduction: Foot is a complex segmented structure formed by the articulation of 26 different bones which are held together by multiple ligaments, extrinsic tendons and the intrinsic muscles of the feet. The assessment of median longitudinal arch serves as an important reference in determining the degree of pes planus or pes cavus. This study aims to find the prevalence of pes planus among the undergraduate medical students of a medical college. Methods: A descriptive cross-sectional study was carried out in the first- and second-year undergraduate medical students of a teaching hospital after taking ethical approval from Institutional Review Committee. The study was conducted from 15th November 2019 to 14th November 2020. Eighty-seven participants were involved in study using the random sampling technique. Foot prints were collected from the participants in the A4 size paper after applying ink over plantar surface of the foot. Measurements were done using the Autodesk Autocad software. Statistical Package for the Social Sciences was used. Point estimate at 95% Confidence Interval was calculated along with frequency and proportion for binary data. Results: Out of the total subjects, 14 (8.04%) (5.14-10.94 at 95% Confidence Interval) presented with flat foot. Similarly, high arched foot was seen in 29 (16.67%) of subjects whereas normal arched foot was seen in 131 (75.29%) subjects. Conclusions: From the current study we conclude that the prevalence of pes planus was slightly higher than that compared with the similar studies.
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Background: Flat foot also called pes planus/fallen arches is common deformity in adults. The present study was undertaken to investigate the prevalence of flat foot among medical students and to find out the association of flat foot with age, gender, body mass index (BMI), foot length and its impact on quality of life and functionality.Methods: A total of 300 medical students of age group 17-23 years were investigated for the presence of flat foot by using navicular drop (ND) test, arch index (AI) and foot posture index (FPI). The data obtained was subjected to statistical analysis using SPSS software.Results: Prevalence of bilateral flat foot was 11.6% (8.3% were females and 3.3% were males). Unilateral was 3% (2% were females and 1% were males) and the correlation of ND, AI, FPI with gender, age was not significant and with BMI, weight was highly significant.Conclusions: Our study showed the presence of bilateral flat foot in 11.6% and unilateral in 3% students. Flat foot is associated with BMI, weight and slightly associated with foot length, height and it is not associated with age, gender. Flat foot effected the quality of life and functionality of the students whose BMI is more.
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The human foot is easily deformed owing to the innate form of the foot or an incorrect walking posture. Foot deformations not only pose a threat to foot health but also cause fatigue and pain when walking; therefore, accurate diagnoses of foot deformations are required. However, the measurement of foot deformities requires specialized personnel, and the objectivity of the diagnosis may be insufficient for professional medical personnel to assess foot deformations. Thus, it is necessary to develop an objective foot deformation classification model. In this study, a model for classifying foot types is developed using image and numerical foot pressure data. Such heterogeneous data are used to generate a fine-tuned visual geometry group-16 (VGG16) and K−nearest neighbor (k-NN) models, respectively, and a stacking ensemble model is finally generated to improve accuracy and robustness by combining the two models. Through k-fold cross-validation, the accuracy and robustness of the proposed method have been verified by the mean and standard deviation of the f1 scores (0.9255 and 0.0042), which has superior performance compared to single models generated using only numerical or image data. Thus, the proposed model provides the objectivity of diagnosis for foot deformation, and can be used for analysis and design of foot healthcare products.
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Flat feet and high-arched feet have been cited as risk factors for musculoskeletal injury and functional problems among runners and other active individuals, although there are no established quantitative definitions or measures for assessing either condition. As part of a larger study, four-plane photographs were made of the weight-bearing right foot of 246 young male Army trainees. These photographs were independently evaluated by six clinicians and rated on a scale of clearly flat-footed (category 1) to clearly high arched (category 5). There was much interclinician variability in the assessments, even for extremes of foot type. The probability of a clinician assessing a foot as clearly flat, given that another clinician had rated the foot as clearly flat, ranged from 0.32 to 0.79, with a median probability of 0.57, while for clearly high-arched feet, probabilities ranged from 0.0 to 1.00, with a median of 0.17. These findings demonstrate the need for objective standards and quantitative methods of evaluating foot morphology.
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In a prospective study in the Israeli army of possible anthropomorphic risk factors for stress fractures, arch type, as accesssed off weight-bearing, was found to have a statistically significant correlation with the incidence of stress fractures. Ten percent of recruits with low arch feet sustained stress fractures as opposed to 31.3 percent with average arches and 39.6 percent with high arches. The finding that recruits with low arches are at less of a risk of stress fractures may partially explain why Black recruits in the American army sustain fewer stress fractures than Caucasians doing the same training, since Blacks are known to have a larger subpopulation with the protective factor of low arches than Caucasians.
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A number of indirect methods of estimating the height of the medial longitudinal arch of the foot have been devised.1 The efficacy of the arch index as a valid and convenient predictor of arch height has been questioned.2 In this study, arch index was measured in 45 elderly subjects and navicular height was measured from weight bearing radiographs. Normalized navicular height was determined by dividing navicular height by foot length as measured from radiographs. A correlation coefficient of r=0.67 was found between navicular height and arch index. The correlation coefficient between arch index and normalized navicular height was found to be r=0.71. Arch index thus provides a simple quantitative means of assessing the height of the medial longitudinal arch with the limitation that only half of the variance in arch height can be explained.
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The purpose of this study was 1) to establish the interrater reliability of classifying foot type by visual appraisal and 2) to determine any relationship between foot type and subsequent knee pain or ankle sprains. Seventy-seven athletes were evaluated by three trained physical therapists to determine interrater reliability of a visual appraisal to identify foot type. Feet were classified according to operational definitions, and specific criteria had to be met for the foot to be classified as supinated, pronated, or neutral. Questionnaires concerning knee pain were completed at the beginning of the season, and incidence of ankle sprain was followed throughout the football and cross country seasons for 55 athletes. The Kappa value for interrater reliability for visually assessing foot type was .72. There was a significant relationship between foot type and knee pain (X2 = 4.45, N = 55, df = 2, p < .05). There was no relationship between foot type and incidence of ankle sprain. These results indicate that 1) physical therapists trained in the procedure can reliably use visual appraisal to classify foot type, and 2) athletes with excessively pronated or supinated foot types may be more susceptible to knee pain than athletes with neutral foot types. J Orthop Sports Phys Ther 1991;14(2):70-74.
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The human foot has frequently been categorized into arch height groups based upon analysis of footprint parameters. This study investigates the relationship between directly measured arch height and many of the footprint parameters that have been assumed to represent arch height. A total of 115 male subjects were measured and footprint parameters were calculated from digitized outlines. Correlation and regression analyses were used to determine the relationship between footprint measures and arch height. It may be concluded from the results that footprint parameters proposed in the literature (arch angle, footprint index, and arch index) and two further parameters suggested in this study (arch length index and truncated arch index) are invalid as a basis for prediction or categorization of arch height. The categorization of the human foot according to the footprint measures evaluated in this paper represent no more than indices and angles of the plantar surface of the foot itself.
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Previous methods of measuring footprints for the purpose of classifying foot type are reviewed. A planimetric method is presented for characterizing footprints using the ratio of the area of the middle third of the footprint to the entire footprint area (excluding the toes). This 'arch index' during 50% body weight standing provides an objective measure for comparative purposes with a measured reliability, within day and between day, of 0.96 and 0.94 respectively. Values measured from footprints taken during other activities show variable responses in different subjects. Examples of the arch index taken from static footprints of various feet are presented and data are reported from 107 randomly selected subjects during half body weight stance. Criteria are suggested for the classification of footprints as high, normal, and flat arch.
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Various radiographic measurements of the normal adult foot have been reported in both early and recent literature; however, a complete description of radiographic quantitative data has yet to be reported. The purpose of this study is to describe the range of the normal foot using standard radiographic techniques that can be applied to the clinical setting. This should provide the data necessary for the accurate interpretation of foot radiographs. This study demonstrates the wide variation in bony relationships of the normal adult foot. When certain recognized criteria of radiographic measurements were evaluated, some were found to be defined as too narrow or inaccurate. Most importantly, because of this wide range, surgical procedures to produce radiographic homogeneity are not indicated. Treatment should be directed specifically toward areas of pain and not radiographic appearance.
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Attempts to evaluate foot arch types from footprint parameters have yielded conflicting results in the past. This could be caused by the uncertainty inherent in the definition of some footprint parameters and the inaccuracy during the footprint acquisition and the parameter calculation phases of the traditional methods. In order to avoid these problems, digital image processing methods were used to acquire and to calculate the Arch Index (AI), a parameter which is robust in its definition. A significant correlation (r = -0.70, p < 0.0001) was found between AI and arch height. Therefore this study confirms that foot arch type does correlate with the footprint parameter, AI. This was further revealed by a new parameter, the Modified Arch Index (MAI), which incorporates foot pressure information in the evaluation. MAI not only correlated well with arch height (r = -0.71, p < 0.0001) but appeared to characterize abnormal foot types better than AI.
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Although clinical evidence suggests a causal relationship between arch structure and musculoskeletal injury patterns, biological variations in soft-tissue structures effect the accuracy of arch-height measurements. Medial longitudinal arch (MLA) structure was assessed clinically and radiographically in 100 consecutive patients with foot problems. Intraclass correlation coefficients were calculated for three radiographic parameters and three anthropometric parameters of the MLA. Intrarater and interrater reliability estimates for the radiographic measurements were uniformly excellent. Intrarater reliability coefficients were higher than interrater coefficients for the three tested anthropometric parameters. The strengths of associations between anthropometric and radiographic data were assessed with Pearson correlation coefficients. The clinically determined ratio of navicular height-to-foot length correlated most closely with the radiographic indices of MLA structure.
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It is widely accepted that persons with flat or high-arched feet are at increased risk of exercise-associated injury, even though this purported association has not been scientifically evaluated. We evaluate the risk of exercise-associated injury among young men with flat, normal, and high-arched feet. A prospective study of 246 US Army Infantry trainees followed up over a rigorous 12-week training program. All subjects were evaluated prior to onset of training. Evaluation included photographs of the right, weight-bearing foot that were digitized and utilized to make several measures of arch height. An army initial entry training center. All trainees beginning army training on 2 successive weeks were potential volunteers. There were no criteria for exclusion other than declining to participate (n = 3). The subjects were healthy, active young men with a mean age of 20.3 years. The occurrence of a lower-extremity musculoskeletal injury resulting in a visit to and a diagnosis by an army physician or physician assistant. Treating physicians and physician assistants were blind to participation status and were not study staff members. On univariate analysis, there was an association between arch height and risk of injury using several alternative operational definitions of foot type. The 20% with the flattest feet were at the lowest risk (reference group; odds ratio, 1.0), with adjusted odds ratios for any musculoskeletal injury of 3.0 (P < .05) for the middle 60% group and 6.1 (P < .05) for the highest 20% group. These findings do not support the hypothesis that low-arched individuals are at increased risk of injury, and they have implications for runners, exercise enthusiasts, and clinicians. It may be possible to prevent substantial morbidity among active populations by identifying individuals at high risk and advising alternate activities.