 Children’s Orthopaedics

Is foot deformity associated with
developmental dysplasia of the hip?
results after examination of 60,844 newborns

Ø. Håberg,
O. A. Foss,
Ø. B. Lian,K. J. Holen

Aims

From Department ofOrthopedic Surgery,
Trondheim University
Hospital, Norway

Between 1996 and 2012, 60,844 children were born in Sør-­Trøndelag county in Norway. In
this cohort study, children with risk factors for DDH were examined using ultrasound. The
risk factors evaluated were clinical hip instability, breech delivery, a family history of DDH,
a foot deformity, and some syndromes. As the aim of the study was to examine the risk for
DDH and foot deformity in the general population, children with syndromes were excluded.
The information has been prospectively registered and retrospectively analyzed.

To assess if congenital foot deformity is a risk factor for developmental dysplasia of thehip (DDH).

Methods

Results
Overall, 494 children (0.8%) had DDH, and 1,132 (1.9%) a foot deformity. Of the children
with a foot deformity, 49 (4.3%) also demonstrated DDH. There was a statistically significant increased association between DDH and foot deformity (p < 0.001). The risk of DDH
was highest for talipes calcaneovalgus (6.1%) and club foot (3.5%), whereas metatarsus
adductus (1.5%) had a marginal increased risk of DDH.

Conclusion
Compared with the general population, children with a congenital foot deformity had asignificantly increased risk for DDH and therefore we regard foot deformity as a true risk
factor for DDH.
Cite this article: Bone Joint J 2020;102-B(11):1582–1586.

Introduction

Correspondence should besent to Ø. Håberg; email:​Oyvind.​Haberg@​helse-​mr.​no; ​oyvindhaberg@​gmail.​com© 2020 Author(s) et al.
doi:10.1302/0301-620X.102B11.
BJJ-2020-0290.R3 $2.00
Bone Joint J
2020;102-B(11):1582–1586.

1582

Developmental dysplasia of the hip (DDH) is awell-­described condition in newborns. Different
screening programmes have been introduced todetect hips in need of treatment, and to minimize
the number of children with late-­diagnosed DDH.
In 2019, Broadhurst et al1 reported that in Englandthere had been no reduction in the incidence ofchildren with late-­diagnosed DDH over the last
35 years. This therefore suggests that there still isa need to improve the screening of children withrisk factors for DDH.
Ultrasound is a method frequently used indiagnosing DDH, either through universal
or selective screening among children at riskof DDH. However, there is no consensus
concerning risk factors for DDH. Clinical hip
instability, a family history of DDH, or breech
deliveries have been reported to be the mostimportant risk factors for DDH.2-7 However, footdeformity has not generally been identified as atrue risk factor for DDH.8-10
Paton et al11 reported a slight increased riskof DDH among children with foot deformities
compared to the general population in Blackburn, UK. In later studies the same group9,12
found that there was no increased risk of
DDH for clubfoot or any other foot deformity,
concluding that foot deformities should not be
considered a risk factor for DDH. Furthermorede Hundt et al,13 in a meta-­analysis, recorded nosignificant relationship between foot deformities
and DDH. In another meta-­analysis, Ibrahim etal14 found a comparable pooled prevalence of
DDH among those with congenital talipes equinovarus (CTEV) and the general population.
Therefore, they too did not recommend ultrasound screening of newborns with CTEV.
Others have reported an increased risk of DDH inchildren with CTEV,15-17 concluding that first-­born
THE BONE & JOINT JOURNALIS FOOT DEFORMITY ASSOCIATED WITH DEVELOPMENTAL DYSPLASIA OF THE HIP?

Population (n = 60,844)

Excluded (n = 27)

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Table I. The observed and expected count of children with and without
developmental dysplasia of the hip (DDH), and with and without footdeformity.
Foot deformity, n
DDH

No

Yes

No

Included (n = 60,817)

Count

59,2401,083

Expected count59,200

1,123

Yes

Clinical examination(n = 52,108)

Clinical andUS examination(n = 8,709)

Fig. 1The study population. US, ultrasound.

females, CTEV, and breech position were all associated with anincreased risk of DDH. These studies reported that the relativerisk of DDH in children with CTEV was 10.34, which is markedly increased. Zhao et al17 also compared CTEV and DDH andrecorded that out of 184 patients with CTEV, five demonstrated
DDH (2.7%). Based on these findings of an increased incidenceof DDH among children with CTEV compared with the general
population, they recommended ultrasound examination of the
hip in this group with foot deformities.
In previous reports from our hospital we have been unable toconclude whether a foot deformity should be considered a risk
factor for DDH.3,4 In this current study we have increased thenumber of children in the survey in order to further examine therelationship between foot deformity and DDH.

Count

445

49

Expected count485

9

Table II. The overall risk and different risk factors of having
developmental dysplasia of the hip (DDH).
FactorTotal, nChildren with DDH, nOverall

60,817494

Risk for DDH, %0.8

Family history

4,162

131

3.1

Breech position

2,548

120

4.7

Foot deformity

1132

49

4.3

CTEV

170

6

3.5

MA

136

2

1.5

CTCV

642

39

6.1

Uncategorized footdeformities

184

2

1.1

CTCV, congenital talipes calcaneovalgus; CTEV, congenital talipes
equinovarus; MA, metatarsus adductus.

16 mHz linear probe in most of the examinations, and since2007 we have used a GE Logic 7 (GE Healthcare, Milwaukee,
Wisconsin, USA) with the same type of probe. The ultrasoundtransducer was placed on the lateral side of the hip, parallel tothe long axis of the body. The femoral head coverage was calculated as a percentage expression of the acetabular coverage of
Methods
the femoral head, where femoral head coverage above 50%
Between 1996 and 2012, 60,844 children were born in Sør-­ is considered to be normal.4 A dynamic examination was
Trøndelag county in Norway. All the children underwent clinical performed to evaluate the stability of the hip. If uncertain ultrahip screening by a paediatrician on the first day after birth. A total sound findings were obtained after the first examination, treatof 27 children with syndromes, who were examined using ultra- ment for DDH was not started, but the child was re-­examinedsound, were excluded from the study; the syndromes included two to three weeks later. If treatment for DDH was started afterDowns, Kippel-­Feil, Merkel-­Gruber, Di George, and arthrogry- the first or second examination, children were then registeredposis. The remaining 60,817 children were all included in the as in need for treatment for DDH. In addition to risk factors,
review. The clinical examination by the paediatrician involved we also registered data such as birth weight and body length,
both the Ortholani18 and Barlow19 tests, the degree of abduction of the mother's child number, gestation week, the paediatrician’s
the hips, and other clinical signs of hip instability.
clinical findings, and the ultrasound results.
Because it has been shown in a randomized trial that there
Foot deformities were classified into four categories: idiowas no significant increased risk for DDH when comparing a pathic CTEV; congenital metatarsus adductus (MA); congenitalgroup undergoing selective screening with a group undergoing talipes calcaneovalgus (CTCV); and a non-­specific foot deforuniversal screening,20we have elected to perform selective mity, which were soft and flexible feet that did not fit into one
ultrasound hip screening. Based on the clinical findings and risk of the other three categories.
factors for DDH, 8,709 (14%) children were examined using
Since registration started in 1996, all data were recorded
ultrasound of the hips.
on paper sheets, and later results of all ultrasound examinaThe reasons for ultrasound examination were as follows: tions were digitalized into a local quality registry for children
pathological clinical findings from the paediatrician's examina- with DDH. The results from this registry were compared withtion, a family history of DDH, breech presentation including data from the birth records of our hospital to ensure that all
breech position and caesarean section, and foot deformity.
foot deformities were registered. In total, 230 children (2.6%)
The ultrasound examination was performed by either one of examined by ultrasound had missing information regarding footthree orthopaedic surgeons and one paediatrician, all who had a deformity and 54 children (0.6%) regarding DDH.
special interest in hip disorders in children. We used a Siemens Ethical approval. The data has been prospectively registered.
Antares (Siemens AG, Munich, Germany) with an 8 mHz to This cohort study was approved by the Regional CommitteeVOL. 102-B, No. 11, NOVEMBER 2020ØYVIND H, OLAV A. F, ØYSTEIN B. L, KETIL J. HOLEN

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Table III. Results of weight, length, and gestational age of children with and without developmental dysplasia of the hip (DDH) foot deformity. The
total represents the selection of 8,709 children examined due to risk factors for DDH.
DDH

Foot deformity

Variable

Total

Yes

No

Yes

No

Mean weight, g (SD;
95% CI)3,430 (638; 3,420 to
3,440)

3,666 (500; 3,634 to
3,697)

3,416 (643; 3,406 to
3,426)

3,435 (535; 3,412 to
3,457)

3,429 (652; 3,419 to
3,440)

Mean body length, cm 49.8 (2.7; 49.7 to 49.8)(SD; 95% CI)

50.4 (2.1; 50.3 to 50.5)

49.7 (2.7; 49.7 to 49.8)

49.6 (2.3; 49.5 to 49.7)

49.8 (2.8; 49.7 to 49.8)

Mean gestational age,wks (SD; 95% CI)

40 (1.1; 40.0 to 40.0)

39.1 (3.2; 39.0 to 39.1)

39.6 (6.7; 39.3 to 39.9)

39.1 (2.1; 39.0 to 39.1)

39.1 (3.1; 39.1 to 39.2)

CI, confidence interval.
Table IV. Results of weight, body length, and gestational age of children with subgroups of foot deformity, and with and without developmental
dysplasia of the hip (DDH).
Variable

CTEV

MAMA and DDH

CTCV

CTCV and DDH

Mean weight,
g (SD; 95% CI)

3,318 (635; 1,548 3,566 (642; 2,630
to 5,020)
to 4,440)

CTEV and DDH

3,448 (526; 2,160 to
4,995)

3,223 (N/A; 3,215
to 3,230)

3,429 (500; 2,085 to
5,050)

3,651 (533; 2,430 to
4,900)

Mean body length,
cm (SD; 95% CI)

48.9 (2.7; 42.0 to 49 (2.7; 44.0 to
56.0)
51.0)

49.5 (2.1; 43.0 to
55.0)

48.5 (0.6; 48.0 to
49.0)

49.6 (2.3; 32.0 to
56.0)

50.3 (1.9; 46.0 to 53.0)

Mean gestationalage, wks (SD; 95% CI)

40 (2.1; 38.0 to
42.1)

39.3 (1.4; 39.1 to
39.5)

39.5 (0.6; 38.6 to
40.4)

39.6 (1.3; 39.5 to
39.7)

39.9 (1.1; 39.7 to 40.2)

40 (1.2; 39.2 to
40.8)*Only two cases in this group.
CI, confidence interval; CTC, congenital talipes calcaneovalgus; CTEV, congenital talipes equinovarus; MA, metatarsus adductus; NA, notapplicable.

for Medical and Health Research Ethics on 6 December 2016(2016/1151).
Statistical analysis. Statistical calculations were performed
using SPSS v. 23 (IBM, Armonk, New York, USA). Results
regarding weight, height, and gestational age are presented asmean with 95% confidence intervals (CIs) and SD. The chi-­squared test was used to assess the association between DDH
and foot deformity.

(1.5%), and 39 of the 642 with CTCV had DDH (6.1%). In
the non-­specified foot deformity group, two of 184 newborns(1.1%) had DDH. Most of the children had a single foot deformity, but 11 children had two different foot deformities (CTEV,
MA, or CTCV). There were no additional risk factors for DDH
among newborns with CTEV, MA, or in the uncategorizedgroup. Among those with CTCV, six of the 39 treated for DDH
had additional risk factors, five with a positive family history,
and one with breech delivery.
Among the 8,709 children who were examined with ultraResults
Between 1996 and 2012, 60,844 children were born in Sør-­ sound, further data was recorded including weight, body length,
Trøndelag county, and after exclusion of those with severe and gestation age (Table III).
The mean birth weight and body length were 3,430 g (SDsyndromes as has been listed, 8,709 children (14.3%) were
examined using ultrasound because of risk factors of DDH and 637.8) and 49.8 cm (SD 2.7), respectively, which are close to
the mean values for all newborns in our country (3,475 g andthese comprise the main study group (Figure 1).
The risk factors in this group leading to ultrasound exam- 50 cm). Children with DDH were heavier, longer, and of higher
ination were: a family history of DDH, 4,162 (48%); breech gestational age than those without DDH, although these differposition, 2,548 (29%); abnormal clinical findings, 1,617 (19%); ences were small. Children with foot deformity were heavier,shorter, and older than children without a foot deformity, but
and foot deformity, 1,132 (13%).
The results regarding children with and without DDH in again the differences between the means were small. Children
terms of foot deformity are presented in Table I. A total of 494 with foot deformity and DDH (except for those with CTEV)
children had DDH and 1,132 children had a foot deformity. had a higher mean birth weight, a higher mean body length,
There was a statistically significant association between DDH and a higher gestational age compared with those without DDH
and foot deformity (p < 0.001) with an increased number of foot (Table IV). Children with CTEV or CTCV and simultaneous
DDH had a higher mean weight, body length, and age. Children
deformity amongst those with DDH.
Among 1,619 children with abnormal clinical findings, 399 with MA had a lower mean weight and body length than those(24.6%) had DDH. The results concerning other risk factors and with MA and simultaneous DDH.
DDH are presented in Table II.
In total, 494 children were treated for DDH, giving an overall Discussion
incidence of DDH of 8.1/1,000. Of the 1,132 newborns with a The aim of our study was to investigate whether foot deformity
foot deformity, 184 newborns had a non-­categorized foot defor- was associated with DDH and we report a significant positive
mity. The remaining 948 newborns were categorized into three association between the two. CTEV and CTCV represented
the majority of children who had an increased risk of DDH,
groups: CTEV, MA, and CTCV.
In the foot deformity group, six out of 170 newborns with whereas MA resulted in only a slightly increased risk of DDH
CTEV had DDH (3.5%), two out of 136 with MA had DDH compared with the general population.
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THE BONE & JOINT JOURNALIS FOOT DEFORMITY ASSOCIATED WITH DEVELOPMENTAL DYSPLASIA OF THE HIP?

We found an overall mean birth weight of 3,430 g, a bodylength of 49.8 cm, and the overall mean gestational age was39.1 weeks (SD 3.1). Compared with all children examinedusing ultrasound, children with a foot deformity (except CTEV)
and DDH had a small increase in weight and gestational age
with a small decrease in body length, although these differences
are most likely to be without clinical significance.
Paton et al,12 in a prospectve longitudinal observational study,
found no children with DDH among newborns with CTEV, andconcluded that CTEV should not be considered as a significant
or “true” risk factor. This is in contrast with our findings where
we found an increased risk of DDH both in the CTEV group andalso in the CTCV group, where six out of 170 children (3.5%)
with CTEV had DDH and 39 out of 642 children (6.1%) with
CTCV had DDH. For MA, two out of 136 children (1.5%) , andfor uncategorized foot deformities, two out of 184 children (1.1%)
had DDH, demonstrating a marginal increase in risk of DDH
compared with the overall risk of DDH of 0.8%. Our findings arein accordance with those of Perry et al,15 who recorded that almost
6% of children with DDH had CTEV. Our results are also similar
to those reported by Zhao et al,17 who found that five children out
of 184 with DDH had CTEV; they concluded that CTEV was arisk factor for DDH, and recommended ultrasound examinationof the hips in these children.
Paton et al9 examined the relationship between different typesof foot deformity and DDH as defined by ultrasound. In theirstudy they classified foot deformities as postural talipes equinoivarus (postural TEV, a CTEV-­like position but soft and clearlyflexible), CTEV, CTCV, and MA. They found that the overall riskof ultrasound-­defined dysplasia or instability was 1:27 in postural
TEV, 1:8.6 in CTEV, 1:5.2 in CTCV, and 1:25 in MA. However,when they examined only the Graf21 type IV instability (irreducible dislocation), the overall risk was 1:436 in postural TEV,
1:15.4 in CTCV, 1:25 in MA, and none in CTEV. These authors
concluded that routine screening for postural TEV and CTEV was
not necessary, but that newborns with CTCV and possibly alsowith MA should be offered an ultrasound of the hip. These results
however are in contrast with ours, where we found a significantly
increased risk of CTEV and a minor increase in risk in the MA
group (p < 0.001).
Perry et al15 examined 119 newborns with CTEV withhip ultrasound. They found that a total of nine hips in sevennewborns were classified as Graf type IIB or worse and werein need of treatment. The treatment frequency was 5.9% (1:17)
in CTEV newborns, which was 45 times more than in thegeneral population (1.3/1,000). They concluded that CTEV wasan important risk factor for DDH and should be included in a
selective ultrasound hip-­screening programme.
In our study population, however, children with CTCV had
the highest risk of DDH, (6.1%), and even discounting the six
children with additional risk factors, there was still a markedly
increased risk of DDH among those with CTCV. In those children with CTEV, our results show that the risk of DDH was
3.5%, which is a little below the increased risk of 5.9% foundby Perry et al.15
The overall incidence for DDH at our hospital was 0.8%,
for MA the incidence was 1.5%, and for the uncategorized footdeformities the incidence was 1.1%, raising the question whether
VOL. 102-B, No. 11, NOVEMBER 2020

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MA and uncategorized foot deformities do in fact require any
special attention, since the risk of DDH was minimal. However,
we have reached the conclusion to continue to offer ultrasoundexamination for all types of foot deformities.
Among the syndromes associated with DDH or foot deformity, Szöke et al22 found that 26 out of 95 patients with amyoplasia (the most common form of arthrogryposis) had hip
dislocations. In our study, 36 children with arthrogryposis
were detected during pregnancy, and 32 women decided to end
their pregnancy, leaving four children who were born and were
excluded from the study.
There are limitations to our study including missing data on
weight, body length, and gestational age of children not examined by ultrasound, and this has prevented more detailed statistical modelling. Also, the number of children with combined
DDH and foot deformity was too low for further statistical
calculations. However, the strength of the study is the large
number of children involved. Also that the examination andregistration were performed by three orthopaedic surgeons andone paediatrician, all with experience and a special interestin hip disorders in children. On the other hand hardly any of
the overall data were missing, and pathological findings weredouble checked in the patients records.
In conclusion, in this study we have found that foot deformity is a significant risk factor for DDH, of which CTEV and
CTCV were the foot deformities with the largest increased riskof DDH. On the basis of these findings we will continue toregard congenital foot deformity as true risk factors for DDH.
Take home message-- Children with a foot deformity has a significant increaed riskfor developmental dysplasia of the hip.
-- Based on this study we recommend ultrasonographic
examination of the hip in newborns with foot deformity.

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Author information:
Ø. Håberg, MD, Orthopedic Surgeon, PhD Candidate
Ø. B. Lian, MD, PhD, Orthopedic Surgeon, Associate Professor

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Department of Orthopaedic Surgery, Kristiansund Hospital, Kristiansund,Norway; Department of Neuromedicine and Movement Science,
Norwegian University of Science and Technology, Trondheim, Norway.
O. A. Foss, MD, PhD, Orthopedic Surgeon, Professor
K. J. Holen, MD, PhD, Orthopedic Surgeon, Associate Professor
Department of Neuromedicine and Movement Science, Norwegian
University of Science and Technology, Trondheim, Norway; Department ofOrthopaedic Surgery, Trondheim University Hospital, Trondheim, Norway.
Author contributions:Ø. Håberg: Designed the study, Wrote the manuscript.
O.A. Foss: Supervised the study, Performed the statistical analysis, Wrotethe manuscript.
Ø.B. Lian: Supervised the study, Wrote the manuscript.
K.J. Holen: Designed the study, Wrote the manuscript.
Funding statement:
No benefits in any form have been received or will be received from acommercial party related directly or indirectly to the subject of this article.
Acknowledgements:
Special thanks to Dr. Helge Rønningen and Dr. Torarin Lamvik, who
performed some of the ultrasound examinations. A very special thanks
to Dr. Ole Jacob Johansen, the pediatrician who performed most of theclinical examinations and also some ultrasound examinations, and to Myrtle
Slettvåg Hoel for her plotting work in establishing our Local Registry forChildren with DDH.
Ethical review statement:This cohort study was approved by the Regional Committee for Medicaland Health Research Ethics on 6 December 2016 (2016/1151).
Open access statement:This is an open-­access article distributed under the terms of the Creative
Commons Attribution Non-­Commercial No Derivatives (CC BY-­NC-­ND 4.0)
licence, which permits the copying and redistribution of the work only, andprovided the original author and source are credited. See https://​creativecommons.​org/​licenses/​by-​nc-​nd/​4.​0/
This article was primary edited by S. P. F. Hughes.

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