The Correlation Between Selected Measurements From Footprint and Radiograph of Flatfoot

Article Outline

• Abstract
• Methods
  • Participants
  • Radiographic Measurements
  • Foot Shape Measurements
  • Radiographic Parameters
  • Geometric Parameters of the Foot
  • Data Analysis
• Results
  • Geometric Parameter Measurements
  • Radiographic Measurements
  • Geometric Parameters Versus Radiographic Parameters
• Discussion
• Conclusions
• Acknowledgment
• References
• Copyright

Abstract 

Chen C-H, Huang M-H, Chen T-W, Weng M-C, Lee C-L, Wang G-J. The correlation between selected measurements from footprint and radiograph of flatfoot.

Objectives

To assess the subarch angle obtained from electronic footprints using a capacitive mat transducer system in children with flatfeet, to evaluate other foot arch indexes, and to compare the results with radiographic measurements.

Design

A cross-sectional study.

Setting

Rehabilitation clinic in a municipal hospital.

Participants

Thirty-two children (age range, 7–13y) diagnosed with flatfeet.

Interventions

Radiographic measurements and foot shape measurements obtained from feet.

Main Outcome Measures

Talo-first metatarsal angle, talocalcaneal angle, talo-horizontal angle, and calcaneal angle were obtained from radiographs. Subarch angle, arch indexes, and long plantar angle were all captured and calculated via a capacitive transducer plate.

Results

Correlations between the subarch angle and the talo-first metatarsal angle, talo-horizontal angle, and arch height were significant, as was the correlation between midfoot arch index and talo-horizontal angle. The forefoot arch index had no significant relationship with radiographic parameters. The talo-horizontal angle and arch height had significant relationships with the long plantar angle.

Conclusions

Measurement of the subarch angle had significant correlation with the radiographic parameters in children with flatfeet and it was accurately and easily obtained from a capacitive forceplate. Measurement of the subarch angle can be a useful tool in the assessment and diagnosis of flatfoot.

Key Words:  Flatfoot , Radiography , Rehabilitation

FLATFOOT IS VERY COMMON in children and the incidence among children varies from 2.8% to 24.2%, depending on assessing methods and subjects’ ages.¹, ² There is little consensus in the literature about which parameters calculated from a footprint are highly significant.³ However, medial longitudinal arch (MLA) has been used as a main reference to diagnose flatfoot or to assess results after the treatment assessment.⁴ The MLA is an integration of the tarsal bones and consists of the talonavicular, talocalcaneal, and naviculocuneiform joints. The main function of the MLA is to absorb the reaction shock force during ambulation.⁵ Flatfeet in children are attributed to ligamentous laxity in the MLA, which results in body weight shifting to the medial side during standing and walking due to the collapsed arch of the foot. Therefore, the arch height is often used as a reference to assess foot problems.⁶ There are many methods currently being used to classify MLA structures,³, ⁵ but the footprint is still the most popular approach to analyze and assess the MLA.⁷

Many parameters from the footprint are used to assess MLA characteristics. Cavanagh and Rodgers⁷ quantified the arch index and calculated the ratio of the area of the middle third to the whole toeless footprint area. Staheli et al⁸ characterized the width of the foot in the area of the arch and the heel, and the ratio between these widths was called the arch index. Rao and Joseph¹ obtained footprints and classified them into normal, high arched, or flat patterns using the width of the midfoot. Forriol and Pascual⁹ proposed using the footprint and the Chippaux-Smirak index to analyze the changes in footprints according to age. These methods were even applied to the clinical fields for assessment of pes planus.¹⁰, ¹¹ However, these indexes only focus on the relationship between the forefoot and midfoot. Kernozek and Ricard¹² observed the relationship between arch type and hindfoot motion. They found that the flat-arched subjects showed greater hindfoot motion. Welton¹³ even proposed dynamic (walking) footprints to reflect additional information when compared with static (standing) ones. These studies frequently obtained the arch index by directly measuring the forefoot and midfoot or midfoot and hindfoot. Conversely, some investigators stated that footprints did not often reflect the real structures of the MLA of the foot. Cobey and Sella¹⁴ stated that footprints were not consistent with the real condition of MLA height using radiographic techniques. Hawes et al¹⁵ compared the anthropometric measurement with the footprint parameters and reported a poor correlation between the 2 data sets. In these contradictory results, the subject selections and diverse methods in the studies were different, which might lead to diverse findings.

Footprints are also used as a tool to assess the relationship with radiographic studies. Vanderwilde et al¹⁶ set up the radiographic evaluation and established age-related normative values with various foot angles. They used radiographic anteroposterior and lateral views to compile a clinically useful reference. Saltzman et al¹⁷ used the anthropometric measurements of MLA height, footprint calculation, and radiographic parameters of the foot to determine the correlation between these methods with interrater and intrarater reliability coefficients. They concluded that the MLA radiographic measurement is a criterion standard for assessing arch structure. Most of the radiographic measurements were found to be highly reliable in assessing foot function.¹⁸ Kanatli et al¹⁹ found significant correlation between footprint measurement and radiographic evaluation for the MLA. The traditional method of acquiring ink footprints is a simple measure, but time-consuming, laborious, and messy. Capacitance footprint is an easier way to overcome the disadvantages of obtaining ink footprints. Foot types calculated from static (standing) footprints displayed less ability than dynamic (walking) footprints to respond to arch changes.¹⁸, ²⁰, ²¹ Therefore, the purpose of this study was to use a capacitance footprint to obtain a subarch angle formed by the forefoot, midfoot, and hindfoot to describe the flatfoot and to correlate the angle with radiographic measurements in a dynamic status.

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Methods 

Participants 

Thirty-two healthy children (mean age, 8.6±1.3y; range, 7–13y) were diagnosed with flatfeet by rehabilitation doctors if the medial arch was depressed or absent on weight bearing,²² and were referred to our clinic for further management. Of those 32 children, 17 were boys and 15 were girls. Their weights ranged from 20 to 70kg, and their heights from 114 to 175cm. They had no neurologic disorders or other musculoskeletal abnormality. Before the children participated in the study, they or their parents gave consent for them to undergo the test procedure. Approval from the clinical ethics committee was also obtained. All children’s demographic data were recorded.

Radiographic Measurements 

We radiographed subjects’ feet while weight bearing. Subjects stood with their knees extended and feet positioned in front of the cassette. Lateral radiographs were obtained using standard procedures. The film packs were placed between the medial borders of the hindfoot and were held vertically in a groove. A radiography tube was directed at 90° to the film and at a distance of 102cm. The exposure was set at 56kV and 5mA/s (100mA×.05s). To ensure the accuracy of the results, the radiographic reports were assessed by an experienced radiologist.

Foot Shape Measurements 

To obtain the foot shapes, we used an EMED ST-4^a capacitance mat transducer system, a sensory density of 4/cm² with sampling rate at 50Hz in 360×190mm plate and a platform with an area of 528×340mm. The system provided high reliability for contact area, pressure, and force variables when measurements were repeated.²³ These variables showed reliability coefficients above .95. After radiographic examination, subjects walked on the EMED ST-4 platform. The platform was mounted into a 7×1m walkway, so that both the platform and the floor were at the same level. The platform was placed 4m from the starting position of the walkway to minimize the effects of acceleration or deceleration. All subjects walked barefoot to obtain a baseline assessment of foot function prior to data collection. Subjects were also asked to walk freely until they reached their natural walking rhythm and speed. After a few minutes of practice at the set walking speed, all subjects were asked to walk naturally in a relaxed and comfortable manner. To reduce error during the measurement process, the walking speeds were controlled within a certain range (−5% to +5%) as measured with a timer. Subjects were also required to walk with a normal arm swing and to look straight ahead at a target placed in front of them to prevent distraction. Data were not recorded if the whole foot did not touch the platform. All subjects completed 3 successful gait cycles for each foot.

Radiographic Parameters 

From the lateral weight-bearing radiograph, we obtained 5 parameters to describe the MLA (fig 1).¹⁶ For data analysis, the angles were also measured with 4 lines¹⁶, ²⁴: (1) talar line: a longitudinal line was determined by the middle points in cortices of the talus; (2) calcaneal line: a target line was drawn along the inferior surface of the calcaneus; (3) metatarsal line: a line was determined by the middle points of superior and inferior cortices of the metatarsal bone; and (4) horizontal line: a line was connected from the fifth metatarsal bone to the inferior process of the calcaneus. From these 4 lines, the following parameters were obtained: (1) talo-first metatarsal angle: a measure of the forefoot and the hindfoot, which becomes wider in the flat foot; (2) talocalcaneal angle: the angle is used to identify the hindfoot with increased valgus heel angle because increased angles are found during valgus angulation; (3) talo-horizontal angle: the angle is obtained to demonstrate the talar inclination; (4) calcaneal pitch angle: an angle that is introduced to describe calcaneal inclination, which is decreased in flatfoot; and (5) arch height: height is defined from the inferior tubercle of the navicular bone to the horizontal line.

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• Fig 1. 

  Template for radiographic measurements of the medial longitudinal arch, calculated on lateral radiography. Abbreviations: AH, arch height; C, calcaneus; CP, calcaneal pitch angle; MC, medial cuneiform bone; MT, metatarsal bone; N, navicular bone; T, talus; TC, talocalcaneal angle; TH, talo-horizontal angle; TM, talo-first metatarsal angle.

Geometric Parameters of the Foot 

We obtained the foot shape and angle analysis using Novel-Ortho software (version 0.87).^a Plantogram calculations were determined using a maximum pressure diagram (fig 2). Two tangent lines were drawn along the lateral and medial margin of the foot. The 4 points (A, A′, B, B′) were defined and the forefoot and heel width were also measured. The 2 lines met to form the long plantar angle. The most lateral point of the border of the medial midfoot (O) made 2 tangents and contacted the forefoot and the hindfoot at 2 points, respectively (C, D). The 3 points O, C, and D formed the subarch angle. A tangent was drawn from point A toward the great toe in contact with point H. The hallux angle was then defined by the 2 lines AH and AB. The narrowest part of the arch was defined as the midfoot length (L). The 2 arch indexes, forefoot arch index (equal to L/A A′) and midfoot arch index (equal to L/B B′), were also defined.

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• Fig 2. 

  The geometric parameters were determined with the EMED ST-4 system. Subarch angle (equal to COD, A, A′, B, B′) defined over the forefoot and heel width, forefoot arch index (equal to L/A A′), midfoot arch index (equal to L/B B′), and long plantar angle determined by AB and A′ B′.

Data Analysis 

We calculated mean values and standard deviations (SDs) for all dependent parameters. The relationship between the right and left feet was compared with paired t test. To determine whether the geometric parameters could be used to assess the flatfeet, the correlation between geometric parameters and radiographic data were analyzed with Pearson correlation coefficients. A significance level of P less than .05 was used for all analyses.

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Results 

There was no significant difference in geometric parameters (P=.05) between the subjects’ right and left feet when using the paired samples t test. Therefore, only the right foot of each subject was selected for assessing the correlation between geometric parameters and the radiographic measurements.

Geometric Parameter Measurements 

The 5 parameters of the subjects’ foot shapes as determined by the EMED-ST4 system are summarized in table 1. The foot length was about 2.5 times the forefoot width. The mid-width value (5.98±0.88cm) was larger than that of the heel width (5.22±0.84cm). The midfoot arch value (.97±.11) was larger than that of the forefoot arch index (.67±.14).

Table 1. Geometric Parameters From EMED System Measurements (N=32)

Radiographic Measurements 

The Vanderwilde method¹⁶ was used to measure the angles. Five radiographic measurements obtained from the radiographic findings included talo-first metatarsal angle, talo-horizontal angle, talocalcaneal angle, calcaneal pitch angle, and arch height, as shown in table 2. Children with flatfeet were diagnosed as such when the talo-first metatarsal angle was greater than 15° or when the talo-horizontal angle was greater than 35°.²⁵, ²⁶, ²⁷ The talocalcaneal angle (41.65°±6.24°) was the largest and the calcaneal pitch angle (9.78°±2.84°) was the smallest.

Table 2. Parameters From Radiographic Findings (N=32)

Geometric Parameters Versus Radiographic Parameters 

The correlations between subarch angle, arch indexes, and radiographic parameters are presented in Table 3, Table 4. The correlations among the subarch angle and the talo-first metatarsal angle (r=.64, P<.01), talo-horizontal angle (r=.53, P<.01), and arch height (r=−.58, P<.01) were significant. The correlation between midfoot arch index and talo-horizontal angle was also significant (r=.41, P<.05). The regression analysis and scattergram of the correlation between the subarch angle and talo-first metatarsal angle (fig 3A), talo-horizontal angle (fig 3B), and arch height (fig 3C) are shown. The regression equations for the subarch angle are talo-first metatarsal angle (in degree) = 0.2084 × subarch angle (in degree) − 17.167, talo-horizontal angle (in degree) = 0.23 × subarch angle (in degree) − 3.427, and arch height (in centimeters) = −0.0144 × subarch angle (in degree) + 4.2676. The forefoot and midfoot arch index had no significant relationship with parameters of the radiographic measurements. The correlation between the long plantar angle and the radiographic parameters is shown in table 4. The talo-horizontal angle and arch height correlated significant with the long plantar angle (r=.39, P<.05; r=−.61, P<.01, respectively).

Table 3. The Correlation of Radiographic Parameters With Subarch Angle, Midfoot Arch Index, and Forefoot Arch Index (N=32)

Abbreviations: AH, arch height; AI, arch index; CP, calcaneal pitch angle; TC, talocalcaneal angle; TH, talo-horizontal angle; TM, talo-first metatarsal angle.

Table 4. The Correlation of Radiographic Parameters With Subarch Angle and Long Plantar Angle (N=32)

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• Fig 3. 

  Scattergram of subarch angle versus (A) talo-first metatarsal angle, (B) talo-horizontal angle, and (C) arch height.

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Discussion 

The results showed that the subarch angle is most suitable to characterize the behavior of the MLA. The vertical height of the navicular tubercle of the MLA has been considered the best anthropometric parameter and has been taken as an important indicator of foot structures.¹⁵, ²⁸ Rossi²⁹ stated that podometric methods could be used as geometric and cartographic parameters for foot typing. He emphasized that foot typing should include both the internal and external features as well as geometrical design, rather than the external measurement only. The subarch angle is determined by forefoot, midfoot, and hindfoot parameters in the footprint. The most lateral point of the border of the midfoot (O in fig 2) is nearest to the reflectional point in the surface of the tarsal epicenter,²⁹ which locates at the center of the calcaneal-cuboid articulation. The subarch angle may best show changes in the foot over the plantar surface, although there are many methods to describe arch height using the footprint. The subarch angle formed by the first metatarsal and the heel bone (C, D) are also reflected in the forefoot and hindfoot area that embraces all the skeletal structure of the foot’s main arch (ie, MLA). Because we know the flatfoot is characterized by forefoot abduction, a decrease in height of the MLA or hindfoot valgus may quantify a diagnosis of flatfoot. The measurement of subarch angle could reflect the arch height related to the lowest point of the MLA area covered by the first metatarsal joint and the hindfoot. Therefore, the subarch angle of the geometric footprint parameters was most related to measurement of flatfoot.

The subarch angle had a high correlation with variable radiographic parameters. The talo-first metatarsal angle has been used to describe the inclination of the talus.¹⁶, ²⁴ The talo-horizontal angle represents the medial and plantar-ward movement of the talus. The angle becomes increasingly positive in subjects with flatfeet. When sagging at the naviculocuneiform joint occurs, the navicular bone slides downward with an increasingly negative value. The subarch angle correlated well with the angle of talo-first metatarsal angle and the talo-horizontal angle, as well as the arch height (see table 3). Therefore, the subarch angle can be regarded as the most representative measurement of the MLA from the anatomic point of view. The calcaneal pitch angle describes the alignment of the hindfoot, and is decreased in subjects with flatfeet. The talocalcaneal angle also demonstrates the angle changes of the hindfoot. These 2 parameters, however, have no significant relationships with subarch angle. Cobey and Sella¹⁴ showed that the measurement of the talocalcaneal angle alone was not representative and could not be reproducible. Saltzman et al¹⁷ also reported lower correlation of the calcaneal pitch angle with the MLA.

Midfoot arch index has been widely used for evaluating and describing flatfeet, but some controversy still exists. Biologic variability due to the migration of soft tissue and bony shape could interfere with the accuracy of arch height.¹⁴, ¹⁵, ³⁰ Therefore, parameters were less valid and less reliable for characterizing the MLA structure. However, some studies preferred these methods and used the footprint for assessing the MLA or for screening foot problems.¹, ⁸ Igbigbi and Msamati² used the methods of measuring the footprint described by Cavanagh and stated that the footprint ratio was a prediction of flatfoot in an indigenous Malawian population. In this study, there were no significant correlations between the radiographic parameters and the midfoot arch. However, some midfoot arch measurements obtained with a static method made significant correlations with radiographic parameters,¹⁵, ¹⁹ which differed from our study. There may be a correlation between static and dynamic measurement; this is worthy of further study.

The forefoot arch index was used to categorize foot morphology.⁹ Flatfoot was defined as a ratio of greater than 45%, but the hindfoot was not taken into consideration in that study. The forefoot arch index, however, revealed no significant correlation with the parameters of the radiographic findings in our study. All cases showed a forefoot arch index greater than 45% with a dynamic measurement in this study. Therefore, dynamic forefoot arch index could be applied to quantify flatfoot in future studies.

Foot placement (long plantar) angle and arch type was used to assess hindfoot motion.¹² The long plantar angle, but not the arch type, was a significant prediction of maximum subtalar pronation. In this study, a significantly negative relationship between the long plantar angle and decreased arch height was found. The long plantar angle exhibited a high correlation with the arch height as that of the subarch angle (r=−.61 vs r=−.58); however, the other radiographic parameter showed no significant correlations in talo-first metatarsal angle (r=.29).

The measurements of subarch angle obtained from footprint analyses are simple, available, reliable, and easily transported electronically. A comparison of the dynapod, the pedobarograph, and the Harris mat to measure foot pressure was made.³¹ The trend for flatfoot assessment using technologic devices for convenience, resolution, and interpretational power is common.³² The subarch angle can present the characteristics of MLA as a predictor or a comparable parameter of the foot.²⁶ However, motion analysis study should be further applied to recognize the difference between the subarch angle change and 3-dimensional variables of foot and ankle joints. Adults with flatfeet should be included to extend the application of the subarch angle. A larger sample size and inclusion of rectus feet studies in future research may confirm the usefulness of the subarch angle in other foot analysis.

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Conclusions 

Subarch angle correlated highly to measurements obtained from radiographs and can be repeated in the EMED system. It can significantly reflect the major component of foot measurement, MLA, which is formed by forefoot, midfoot, and hindfoot. The subarch angle also can be used to analyze the dynamic characteristics from the capacitance mat transducer system. Therefore, the measurement of the subarch angle can be a useful tool in the assessment and diagnosis of flatfoot.

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Acknowledgment 

We thank Chei-Wei Hsieh, MD, for the radiographic measurements.

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References 

1. Rao UB , Joseph B . The influence of footwear on the prevalence of flat foot. A survey of 2300 children . J Bone Joint Surg Br . 1992;74:525–527
   • View In Article
   • MEDLINE
2. Igbigbi PS , Msamati BC . The footprint ratio as a predictor of pes planus (a study of indigenous Malawians) . J Foot Ankle Surg . 2002;41:394–397
   • View In Article
   • Abstract
   • Full-Text PDF (659 KB)
   • CrossRef
3. Menz HB . Alternative techniques for the clinical assessment of foot pronation . J Am Podiatr Med Assoc . 1998;88:119–129
   • View In Article
   • MEDLINE
4. Gilmour JC , Burns Y . The measurement of the medial longitudinal arch in children . Foot Ankle Int . 2001;22:493–498
   • View In Article
   • MEDLINE
5. Huang CK , Kitaoka HB , An KN , Chao EY . Biomechanical evaluation of longitudinal arch stability . Foot Ankle . 1993;14:353–357
   • View In Article
   • MEDLINE
6. Cowan DN , Jones BM , Robinson JR . Foot morphologic characteristics and risk of exercise-related injury . Arch Fam Med . 1993;2:773–777
   • View In Article
   • MEDLINE
7. Cavanagh PR , Rodgers MM . The arch index (a useful measure from footprints) . J Biomech . 1987;20:547–551
   • View In Article
   • MEDLINE
   • CrossRef
8. Staheli LT , Chew DE , Corbett M . The longitudinal arch. A survey of eight hundred and eighty-two feet in normal children and adults . J Bone Joint Surg Am . 1987;69:426–428
   • View In Article
   • MEDLINE
9. Forriol F , Pascual J . Footprint analysis between three and seventeen years of age . Foot Ankle . 1990;11:101–104
   • View In Article
   • MEDLINE
10. Echarri JJ , Forriol F . The development in footprint morphology in 1851 Congolese children from urban and rural areas, and the relationship between this and wearing shoes . J Pediatr Orthop B . 2003;12:141–146
    • View In Article
    • MEDLINE
    • CrossRef
11. Rose GK , Welton EA , Marshall T . The diagnosis of flat foot in the child . J Bone Joint Surg Br . 1985;67:71–78
    • View In Article
    • MEDLINE
12. Kernozek TW , Ricard MD . Foot placement angle and arch type (effect on rearfoot motion) . Arch Phys Med Rehabil . 1990;71:988–991
    • View In Article
    • MEDLINE
13. Welton EA . The Harris and Beath footprint (interpretation and clinical value) . Foot Ankle . 1992;13:462–468
    • View In Article
    • MEDLINE
14. Cobey JC , Sella E . Standardizing methods of measurement of foot shape by including the effects of subtalar rotation . Foot Ankle . 1981;2:30–36
    • View In Article
    • MEDLINE
15. Hawes MR , Nachbauer W , Sovak D , Nigg BM . Footprints as a measure of arch height . Foot Ankle . 1992;2:30–36
    • View In Article
    • MEDLINE
16. Vanderwilde R , Staheli LT , Chew DE , Malagon V . Measurements on radiographs of the foot in normal infants and children . J Bone Joint Surg Am . 1988;70:407–415
    • View In Article
    • MEDLINE
17. Saltzman CL , Nawoczenski DA , Talbot KD . Measurement of the medial longitudinal arch . Arch Phys Med Rehabil . 1995;76:45–49
    • View In Article
    • Abstract
    • Full-Text PDF (553 KB)
    • CrossRef
18. Cavanagh PR , Morag E , Boulton AJ , Young MJ , Deffner KT , Pammer SE . The relationship of static foot structure to dynamic foot function . J Biomech . 1997;30:243–250
    • View In Article
    • Abstract
    • Full-Text PDF (1021 KB)
    • CrossRef
19. Kanatli U , Yetkin H , Cila E . Footprint and radiographic analysis of the feet . J Pediatr Orthop . 2001;21:225–228
    • View In Article
    • MEDLINE
    • CrossRef
20. Kaufman KR , Brodine SK , Shaffer RA , Johnson CW , Cullison TR . The effect of foot structure and range of motion on musculoskeletal overuse injuries . Am J Sports Med . 1999;27:585–593
    • View In Article
    • MEDLINE
21. Mathieson I , Upton D , Prior TD . Examining the validity of selected measures of foot type (a preliminary study) . J Am Podiatr Med Assoc . 2004;94:275–281
    • View In Article
    • MEDLINE
22. Franco AH . Pes cavus and pes planus. Analyses and treatment . Phys Ther . 1987;67:688–694
    • View In Article
    • MEDLINE
23. Quaney B , Meyer K , Cornwall MW , McPoil TG . A comparison of the dynamic pedobarograph and EMED systems for measuring dynamic foot pressures . Foot Ankle Int . 1995;16:562–566
    • View In Article
    • MEDLINE
24. Bordelon RL . Correction of hypermobile flatfoot in children by molded insert . Foot Ankle . 1980;1:143–150
    • View In Article
    • MEDLINE
25. Kalen V , Brecher A . Relationship between adolescent bunions and flatfeet . Foot Ankle . 1988;8:331–336
    • View In Article
    • MEDLINE
26. Gould N . Evaluation of hyperpronation and pes planus in adults . Clin Orthop Relat Res . 1983;(181):37–45 Dec
    • View In Article
27. Wenger DR , Mauldin D , Speck G , Morgan D , Leiber RL . Corrective shoes and inserts as treatment for flexible flatfoot in infants and children . J Bone Joint Surg Am . 1989;71:800–810
    • View In Article
    • MEDLINE
28. Gilmour JC , Burns Y . The measurement of the medial longitudinal arch in children . Foot Ankle Int . 2001;22:493–498
    • View In Article
    • MEDLINE
29. Rossi WA . Podometrics (a new methodology for foot typing) . Contemp Podiatr Physician . 1992;28–39
    • View In Article
30. Me-Dan O , Kath G , Zeev A , et al.   The medical longitudinal arch as a possible risk factor for ankle sprains (a prospective study in 83 female infantry recruits) . Foot Ankle Int . 2005;26:180–183
    • View In Article
    • MEDLINE
31. Hughes J , Kriss S , Klenerman L . A clinician’s view of pressure (a comparison of three different methods of measurement) . Foot Ankle . 1987;7:277–284
    • View In Article
    • MEDLINE
32. Tareco JM , Miller NH , MacWilliams BA , Michelson JD . Defining flatfoot . Foot Ankle Int . 1999;20:456–460
    • View In Article
    • MEDLINE

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