ORIGINAL ARTICLES

The Effects of Talus Control Foot Orthoses in Children withFlexible Flatfoot

So Young Ahn, MD, MS*Soo Kyung Bok, MD, PhD*

Bong Ok Kim, MD, PhD*In Sik Park, MS, BS(Pod, CPed)†

Background: A talus control foot orthosis (TCFO) combines an inverted rigid footorthosis (RFO) with a broad upright portion that rises well above the navicular to coverand protect the talonavicular joint. We sought to identify the therapeutic effect of TCFOsin children with flexible flatfoot.

Methods: Flexible flatfoot was diagnosed in 40 children when either of the feet hadgreater than 48 valgus of resting calcaneal stance position (RCSP) angle and one of theradiographic indicators was greater than 308 in anteroposterior talocalcaneal angles, 458

in lateral talocalcaneal angles, and 48 in lateral talometatarsal angles and less than 108

of calcaneal pitch in barefoot radiographs. Of 40 children with flexible flatfoot, 20 werefitted with a pair of RFOs and 20 with TCFOs, randomly. Follow-up clinical andradiographic measurements were completed 12 months later.

Results: All of the radiographic indicators changed toward the corrective direction inboth groups. There were significant improvements in calcaneal pitch and RCSP in bothgroups (P , .05). In the TCFO group, the anteroposterior talocalcaneal angle and theRCSP showed statistically significant improvement compared with the RFO group.

Conclusions: In this study, the TCFO was more effective than the RFO at treatingchildren with flexible flatfoot. (J Am Podiatr Med Assoc 107(1): 46-53, 2017)

Flatfoot is one of the most common diseases treated ata pediatric rehabilitation department.1 It refers to the

loss of the medial longitudinal arch of the foot as aresult of complex action between the forefoot, mid-foot, and hindfoot.2 The incidence of flatfoot varies

widely by age. According toVolpon,3 rapidprogressionofmedial longitudinalarch development was observedbetween 2 and 6 years of age, and the incidence ratedrops sharply at age 6 years. However, some children

remain flatfooted because their medial longitudinalarch does not develop normally for some reason.

Flatfoot can be divided into flexible type and rigidtype. With flexible flatfoot, there is loss of arch heightin the weightbearing position (closed kinetic chain).

With rigid flatfoot, the arch is not present, whetherbearing weight or not (closed and open kineticchain).4,5 Rigid flatfoot is most often found in people

who have congenital coalition, arthritis, vertical talus,

or structural defects that require surgical treatment.6

In most children, flexible flatfoot deformity does not

cause any clinical symptoms. However, if the child

has symptomatic, rigid, or progressive flatfoot, he or

she needs to be closely examined and managed

appropriately.7 The symptoms include lower-limb

pain, increased lower-limb fatigue, Achilles tendin-

opathy, and abnormal gait patterns. If children are left

untreated, the symptoms may further aggravate,

resulting in secondary deformities, such as bunions,

hallux rigidus, and pelvic malalignment.

Factors predisposing to flatfoot can usually be

categorized. Markers of increased susceptibility to

physiologic flatfoot include age, sex (male), weight

(obesity), and joint hypermobility. Conversely, non-

physiologic flatfoot markers include neuromuscular

disorders (cerebral palsy or myopathy), hereditary

disorders (Down’s syndrome or Marfan syndrome),

collagen disease (ligament laxity), external injury,

and skeletal abnormalities.4,8

Conservative and surgical interventions are both

used to treat flatfoot. However, surgical intervention

*Department of Rehabilitation Medicine, Chung Nam

National University Hospital, Daejeon, Republic of Korea.†Korean Pedorthic Institute, Goyang, Republic of Korea.Corresponding author: So Young Ahn, MD, MS, Depart-

ment of Rehabilitation Medicine, Chung Nam National

University Hospital, 266 Munhwa-ro, Jung-gu, Daejeon, 301-

747, Republic of Korea. (E-mail: hitz97@hanmail.net)

46 January/February 2017 � Vol 107 � No 1 � Journal of the American Podiatric Medical Association

is rarely chosen when conservative treatment fails.Although a variety of flatfoot supports have beentraditionally used, their effectiveness has beencontroversial among scholars. Whitford and Ester-man9 demonstrated that there was no evidence tojustify the use of in-shoe orthoses for the manage-ment of flexible flatfoot in children. However,according to Jay and colleagues,10 individuals whowore a dynamic stabilizing innersole system tocorrect overpronation showed improvement in theresting calcaneal stance position (RCSP). Also, astudy by Kulcu et al11 reported that the use of asilicone insole did not affect gait patterns in patientswith flexible flatfoot. However, radiographic mea-surements made before and after wearing the insoleshowed a significant improvement.

There are basically two types of orthoses: solidand soft. The solid foot orthosis, also called rigidfoot orthosis (RFO), is a corrective device capableof controlling movement-related pathologic abnor-malities.12 The soft foot orthosis, also calledaccommodative orthosis, allows the foot to com-pensate. In a previous study, we found a significantimprovement in radiographic indicators after 24months of RFO use in children with pes planus.13

We hypothesize that an RFO is effective for themanagement of pes planus and that an RFO withtalus control is a more effective device for childrenwith flatfoot. Therefore, we sought to investigatethe effect of a talus control foot orthosis (TCFO),with the additional navicular padding on an existingRFO, in children older than 6 years with flexibleflatfoot (Fig. 1).

Participants and Methods

The study was approved by the ethics committee ofChung Nam National University Hospital, Daejeon,Republic of Korea, and informed consent wasreceived from each participant. The present studyincluded 40 children diagnosed as having flexibleflatfoot who visited the Department of PediatricRehabilitation at Chung Nam National UniversityHospital, Daejeon, Republic of Korea (Table 1).Forty children were randomly prescribed a footorthosis: 20 an RFO and 20 a TCFO. The RFO groupconsists of 12 boys and 8 girls with a mean 6 SDage of 10.14 6 4.99 years and a mean 6 SD bodymass index (calculated as weight in kilogramsdivided by height in meters squared) of 18.37 6

4.67. The TCFO group consists of 12 boys and 8 girlswith a mean 6 SD age of 9.59 6 4.24 years and amean 6 SD body mass index of 19.18 6 2.39. Theexclusion criteria included rigid flatfoot caused by

hereditary foot disease or neuromuscular disease,fixed foot deformity, or previous surgery.

Flatfoot was defined when either of the feet had

more than 48 valgus of RCSP angle and oneabnormal radiographic finding of greater than 308

in anteroposterior talocalcaneal angles (APTCAs),458 in lateral talocalcaneal angles (LTTCAs), and 48

in lateral talometatarsal angles (LTTMAs) and lessthan 108 of calcaneal pitch (CP).

We instructed participants to wear the orthosis formore than 8 hours per day. Participants were trainedhow to walk by striking their heels in the early stancephase and swinging their arms in the reciprocaldirection. The biomechanical RCSP measurementand the radiographic evaluation were conductedbefore and 12 months after wearing the foot orthoses.

Measurement of the RCSP

Participants were asked to lie face down on a bedparallel to the ground with their feet over the edge ofthe bed. An investigator examined their feet manu-ally and put three dots on the upper, middle, andlower parts of the calcaneus to draw a bisection linewith no regard to the fat around the calcaneus. TheRCSP was measured when individuals were standing

with their feet fist-width apart. The angle betweenthe bisector of the calcaneus and the perpendicularline to the ground was measured (Fig. 2).

Radiographic Measurement

All of the radiographs for measuring radiographicindicators before and after treatment were takenwith the participant standing barefoot with normalbase and angle of gait. The participants’ feet wereboth examined in the anteroposterior and lateralviews. The APTCA was measured in the anteropos-terior view to evaluate the rearfoot alignment. TheLTTCA, LTTMA, and CP were measured in thelateral view to evaluate the medial longitudinal archof the foot. The talocalcaneal angle refers to theangle between the longitudinal axis of the talus andthe calcaneus measured on a weightbearing foot

radiograph. The talometatarsal angle refers to theangle between the longitudinal axis of the talus andthe first metatarsal bone. Calcaneal pitch is theangle formed by the baseline and a line from thelower margin of the calcaneus (Fig. 3).14

RFO versus TCFO

Both foot orthoses were manufactured based onBlake’s inverted technique, in which the control

Journal of the American Podiatric Medical Association � Vol 107 � No 1 � January/February 2017 47

target is the medial side of the calcaneus. When

patients were prescribed an inverted orthosis man-

ufactured based on Blake’s technique, the ratio of the

correction angle of the RCSP and the pouring angle

of the negative mold was 5:1. The initial correction

angle is usually two-thirds of the total correction

angle. For example, if the RCSP is �68 inverted, the

correction angle of the RCSP would be 68 and the

pouring angle would be 308 (68 x 5). Because the

initial correction angle starts with two-thirds of the

total correction angle, it should be inverted 208. The

TCFO is a modified Blake’s inverted orthosis, having

a medial flange brought up around the medial side of

the navicular. When manufacturing the TCFO, the

medial portion of the positive mold is adjusted for

navicular support (Fig. 4).

Each custom-made foot orthosis was fabricated by

Biomechanics Co, Goyang, Republic of Korea. For

capturing the negative foot impression accurately, the

neutral position of weightbearing plaster cast tech-

nique, which is one of the most popular and reliable

measurements of forefoot/rearfoot relationships, was

performed.15 The rigid orthotic shell is made of

polypropylene with a thickness of 5 mm, and ethylene

vinyl acetate was used for heel posting (Fig. 1).

Statistical Analysis

Statistical analysis was performed using a statistical

software program (IBM SPSS Statistics for Windows,

version 19.0; IBM Corp, Armonk, New York). To

minimize the error range, two physiatrists measured

the radiographic parameters independently. All of the

values were averaged with a standard deviation. The

paired-samples t test was used to compare the RCSP

and the radiographic measurements before and after

wearing foot orthoses. Also, an independent-samples

t test was used to perform a comparative analysis of

the effect of the two orthoses. A P , .05 was

considered statistically significant.

Results

The RCSP

The mean 6 SD value of the RCSP changed from

–7.558 6 4.078 to –3.558 6 3.218 in the RFO group

Figure 1. A, Talus control foot orthosis. B, Rigid foot orthosis.

Table 1. Characteristics of the 40 Study Participants

CharacteristicRFO Group

(n ¼ 20)TCFO Group

(n ¼ 20)

Age (years) 10.14 6 4.99 9.59 6 4.24

Sex, M:F (No.) 12:8 12:8

Height (cm) 138.23 6 10.17 139.28 6 12.78

Weight (kg) 35.13 6 16.93 37.41 6 11.33

BMI 18.37 6 4.67 19.18 6 2.39

Note: Values are given as mean 6 SD except where

indicated otherwise.

Abbreviations: BMI, body mass index (calculated as weight

in kilograms divided by height in meters squared); RFO, rigid

foot orthosis; TCFO, talus control foot orthosis.

48 January/February 2017 � Vol 107 � No 1 � Journal of the American Podiatric Medical Association

and from –9.285 6 2.958 to –2.058 6 1.938 in the

TCFO group (Figs. 5 and 6 and Table 2).

Radiographic Measurements

The mean 6 SD value of the APTCA changed from

35.758 6 8.468 to 33.42 6 7.428 in the RFO group and

from 36.918 6 7.378 to 33.088 6 7.058 in the TCFO

group (Fig. 5 and Table 2). The mean 6 SD value of

the LTTCA changed from 43.678 6 11.898 to 47.178

6 6.788 in the RFO group and from 46.508 6 9.018

to 48.878 6 7.568 in the TCFO group. The mean 6

SD value of the LTTMA changed from 20.298 6

12.948 to 21.548 6 13.858 in the RFO group and from

18.278 6 7.838 to 18.518 6 6.848 in the TCFO group.The mean 6 SD value of CP changed from 8.338 6

6.048 to 13.318 6 5.668 in the RFO group and from8.948 6 4.348 to 15.058 6 4.848 in the TCFO group.

Discussion

Flexible flatfoot is one of the most common footdeformities in children whose medial longitudinalarch disappears during weightbearing. Subtalaroverpronation is one of the characteristics offlatfoot. The subtalar joint normally pronatesapproximately 48 during the first 25% of the stancephase. In the case of flatfoot, the subtalar joint

Figure 2. Calcaneal bisection and measurement of the resting calcaneal stance position.

Figure 3. Anteroposterior and lateral views of both feet parameters: 1* anteroposterior talocalcaneal angle, 2*lateral talocalcaneal angle, 3* lateral talometatarsal angle, and 4* calcaneal pitch.

Journal of the American Podiatric Medical Association � Vol 107 � No 1 � January/February 2017 49

pronates more than 48 during the early stance phase

or remains pronated after the early stance phase.

Thus, the medial longitudinal ligaments have to

resist the excessive and prolonged force by abnor-

mal range of pronation.14 Symptoms of flatfoot are

usually accompanied by anatomical abnormalities

such as subtalar subluxation, medial protrusion, and

collapse of the medial longitudinal arch caused by

talar adduction and plantarflexion, tibial internal

rotation, calcaneal eversion, and plantarflexion at

the subtalar joint. Also, forefoot abduction occurs at

the midtarsal joint, which results in more relative

supination in the forefoot compared with the

hindfoot.16

Treatment of flexible flatfoot has been the subject

of controversy among scholars, especially nonsur-

gical treatment using foot orthoses. The effective-

ness of a variety of foot orthoses and shoes has

been examined in many studies, with diverse

opinions on their efficacy.9,10,12,17-19

In a study by Wenger et al,17 children with flexible

flatfoot aged 1 to 6 years wore orthopedic shoes,

heel cups, and custom-molded plastic inserts

(University of California Biomechanics Laboratory,

San Francisco, California); however, no significant

difference was found between the control and

treatment groups. However, in that study, old-style

foot orthoses were used, and they enrolled children

with flatfoot younger than 6 years, who were still

developing the medial longitudinal arch. Because

the medial longitudinal arch develops on its own by

age 6 years, it is not appropriate to conclude that

the foot orthosis used in the present study produced

meaningful improvements in the RCSP and the

radiographic measurements without comparison

with the control group. Therefore, we included

children older than 6 years and measured both

RCSP and radiographic measurements to enhance

the reliability of the results.

In the previously mentioned study by Whitford and

Esterman,9 children aged 7 to 11 years who wore

foot orthoses for 12 months showed no improvement

in gross motor proficiency, self-perception, exercise

efficiency, and pain. It is believed that the effect of

controlling the movement-related pathology was

decreased compared with an RFO because the type

of orthosis used in that study was semirigid. In the

present study, we used an RFO to obtain maximal

correctional efficacy.

In the present study, both foot orthoses were

manufactured based on Blake’s inverted technique.

It is a technique developed by Richard L. Blake to

treat children with severe flatfoot whose RCSP is

less than�58. The medial side of the calcaneus was

the basic point for the correction. The twisting

around the oblique axis of the subtalar joint and the

long axis of the midtarsal joint induces calcaneal

inversion and forefoot eversion. So that it can

contribute to the rearfoot supination and talar

dorsiflexion, abduction, consequently to form the

medial longitudinal arch. The TCFO has an addi-

tional broad upright portion rising well above the

navicular bone that affects the location and move-

ment of the navicular and the talonavicular joint,

resulting in effective correction of plantarflexion

and medial deviation of the talus (Fig. 7).20,21

Figure 4. A, Talus control foot orthosis. The arrow indicates the broad upright portion rising above thenavicular bone. B, Rigid foot orthosis.

50 January/February 2017 � Vol 107 � No 1 � Journal of the American Podiatric Medical Association

Figure 6. Improvement of calcaneal pitch (CP) (A) and resting calcaneal stance position (RCSP) (B) in therigid foot orthosis (RFO) and talus control foot orthosis (TCFO) groups. *P , .05.

Figure 5. Mean 6 SD changes before and after treatment in the anteroposterior talocalcaneal angle (APTCA)(A), lateral talocalcaneal angle (LTTCA) (B), lateral talometatarsal angle (LTTMA) (C), calcaneal pitch (CP)(D), and resting calcaneal stance position (RCSP) (E) in the rigid foot orthosis (RFO) and talus control footorthosis (TCFO) groups. *P , .05.

Journal of the American Podiatric Medical Association � Vol 107 � No 1 � January/February 2017 51

We measured four radiographic indicators for the

evaluation of midfoot and hindfoot alignment. For

hindfoot alignment, the lateral and anterior talocal-

caneal angles and CP were measured. For midfoot

alignment, the talometatarsal angle was used. By

measuring these various angles, we tried to increase

the reliability of the results and evaluate the

relationship between each part of the foot.

In the present study, the RCSP and all of the

radiographic indicators changed toward the correc-

tive direction in both groups 12 months after

wearing foot orthoses compared with those before

treatment. However, both groups showed significant

improvements in their RCSP and CP (P , .05).

Positional changes in the location of the sagittal and

coronal planes of the calcaneus are expected, which

means changes in the rearfoot in the early phase

because Blake’s technique intends to correct the

medial side of the calcaneus. In both groups, the

LTTCA and the LTTMA did not show significant

improvement 12 months after wearing the orthosis.

In previous studies with an RFO applied to flexible

flatfoot, the APTCA and the LTTMA showed

significant improvement, and the LTTCA showed a

tendency toward improving after 24 months of RFO

application.13 Changes in the sagittal and transverse

planes of the talus are expected after wearing foot

orthoses longer than 24 months. Future research

including more long-term follow-up is needed.

The TCFO produced considerable improvements

in the APTCA and the RCSP compared with the

RFO. It is assumed that because medial flange

pressure, which supports the navicular bone, was

loaded from medial to lateral it produced changes in

Table 2. Changes in Radiographic Indicators and RCSP

Indicator

RFO Group TCFO Group

Initial After 12 mo Initial After 12 mo

APTCA (8) 35.75 6 8.46 33.42 6 7.42 36.91 6 7.37 33.08 6 7.05a

LTTCA (8) 43.67 6 11.89 47.17 6 6.78 46.50 6 9.01 48.87 6 7.56

LTTMA (8) 20.29 6 12.94 21.54 6 13.85 18.27 6 7.83 18.51 6 6.84

CP (8) 8.33 6 6.04 13.31 6 5.66a 8.94 6 4.34 15.05 6 4.84a

RCSP (8) –7.55 6 4.07 –3.55 6 3.21a –9.25 6 2.95 –2.05 6 1.93a

Note: Values are given as mean 6 SD.

Abbreviations: APTCA, anteroposterior talocalcaneal angle; CP, calcaneal pitch; LTTCA, lateral talocalcaneal angle; LTTMA,

lateral talometatarsal angle; RCSP, resting calcaneal stance position; RFO, rigid foot orthosis; TCFO, talus control foot orthosis.aP , .05 compared with initial evaluation by paired t test.

Figure 7. Mechanical forces of the rigid foot orthosis (RFO) and the talus control foot orthosis (TCFO) at the 1*talus, 2* talonavicular joint, 3* metatarsal, 4* inferior calcaneus, 5* medial calcaneus, and 6* navicular.

52 January/February 2017 � Vol 107 � No 1 � Journal of the American Podiatric Medical Association

the location of the transverse plane of the talus andthe coronal plane of the calcaneus rather than

producing changes in the location of the sagittalplane of the subtalar joint in the rearfoot.

This study is based on the study by Volpon3 thatshowed complete normal foot development in 6

years. Having a control group that did not wear foot

orthoses is important for improving the complete-ness of this study. To minimize errors, participants

were limited to children older than 6 years. In lightof the authors’ experience of managing a ‘‘shoe

clinic’’ for more than 10 years, we verified theclinical effects of the foot orthosis. Although the

normal foot alignment group showed some im-

provement after 6 years, we are convinced that archdevelopment will be faster with foot orthoses,

which also corresponds with the study by Gouldet al.22 Also, ethical problems occurred in enrolling

a control group that had no intervention despite

severe flexible flatfoot because flatfoot is one of themost common foot problems in childhood and can

affect the walking pattern and lead to fatigue andfoot deformity.18 Future research with a larger

sample size and a control group is warranted toquantify and generalize the effects of the foot

orthosis.

Conclusions

The present results suggest that the use of footorthoses in children with flexible flatfoot produced

improvement in clinical and radiographic measure-ments in both the RFO and TCFO groups. However,

much more improvement was seen in the APTCA

and the RCSP in the TCFO group. The resultssuggest that the TCFO is more effective than the

RFO for the treatment of flexible flatfoot in children,indicating its usefulness in the future treatment of

children diagnosed as having serious flatfoot.

Financial Disclosure: None reported.

Conflict of Interest: None reported.

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