Abstract
Purpose
The aim of the study was to examine motor abilities in children treated for idiopathic clubfoot with either the traditional extensive surgery method or the Ponseti method, and compare their motor skills with a control group without clubfoot.
Methods
A total of 89 children treated according to the traditional method (mean age 9.0 years, 7 to 10) and 93 treated ad modum Ponseti (mean age 8.8 years, 7 to 10) were recruited from a multicentre clinical study in Norway. A total of 45 age-matched children without clubfoot were recruited from a nearby school. They were all assessed with the Movement Assessment Battery for Children – Second Edition (MABC-2), which evaluates motor performance. We applied Analysis of Covariance for comparison of the two treatment methods and adjusted for gender, laterality, comorbidity, achillotomy or more extended surgery, physiotherapy and the age when the child walked independently.
Results
We found no significant difference in any of the various components or the total score of the MABC-2 between patients treated with the two different methods. In all, 76% of the children treated according to the traditional method and ad modum Ponseti, and 96% in the control group, respectively, were classified as having normal motor abilities.
Conclusion
About three-quarters of children aged nine years and treated for idiopathic clubfoot had normal motor abilities. We found similar results in patients treated with the traditional method and the Ponseti method.
Level of Evidence
II
Keywords: clubfeet, Ponseti, Movement Assessment Battery for Children, motor abilities, controlled study
Introduction
Congenital talipes equino varus, also known as congenital idiopathic clubfoot, is one of the most common birth defects involving the musculoskeletal system.1 The severity of the condition varies from the most rigid cases to milder forms. The aetiology is unknown but is believed to be multifactorial. Some researchers have reported signs of a general deficit in motor skills in patients with idiopathic clubfoot,2 others have found that children with clubfoot cope relatively well with physical activity3 and some researchers have found inferiority in gait.4 Only a few studies reveal motor skills or functional results in the age group five to 11 years2,4-6 and very few have looked into motor skills also involving upper extremities in the same age group.2,4 To our knowledge only one study has specifically looked into motor abilities in clubfoot patients treated ad modum Ponseti in the same age group as the present study.6
Clubfoot can be managed by conservative treatment or surgery. Conservative treatment commonly includes stretching and serial casting for a few weeks followed by bracing ad modum Ponseti.7 In most cases the Ponseti method also includes an achillotomy when the child is a few months old.7 The Ponseti method has been widely used for decades and has been reported to reduce the need for major foot surgery.8,9 The traditional method includes posteromedial or posterior release as the primary surgical intervention.10 No randomized clinical trial has compared results with the Ponseti method against the traditional method, and only few non-randomized studies have compared the two methods.11 Only a few small studies have evaluated motor ability or skills, which is considered to be an important outcome measure in the growing child.2
The aim of the present study is to evaluate motor abilities among children with clubfoot according to a standardized test: the Movement Assessment Battery for Children – Second Edition (MABC-2).12 The primary objectives are to compare motor ability in patients treated with the Ponseti method and the traditional method. The secondary objectives are to compare the patients’ motor abilities with children without clubfoot and to evaluate static and dynamic balance in patients with unilateral versus bilateral involvement.
Patients and methods
Study design and ethics
This was a retrospective cross-sectional cohort study that included children with clubfoot treated with two different methods and age-matched children without clubfoot.
The study was approved by the Regional Committee for Medical and Health Research Ethics of Western-Norway (REK Vest), 2010/1882.
Participants
In all, 56 girls and 126 boys with clubfoot and 45 age-matched children without clubfoot participated. All patients had idiopathic congenital clubfoot and had been treated according to the traditional method (n = 89, mean age 9.0, 7 to 10) or the Ponseti method (n = 93, mean age 8.8, 7 to 10) (Table 1). The patients were examined in 2010 and 2014, respectively, and they could therefore be compared according to age.
Table 1.
Patient demographics
| Traditional (n = 89) | Ponseti (n = 93) | |
|---|---|---|
| Age (yrs), mean (range) | 8.9 (7-10) | 8.7 (7-10) |
| Gender (boys), n (%) | 60 (67) | 66 (72) |
| Height (cm), mean (SD) | 137.9 (6.8) | 137.0 (7.7) |
| Weight (kg), mean (SD) | 34.8 (7.8) | 33.0 (6.9) |
| Laterality, n (%)* | ||
| Right | 29 (31) | 39 (42) |
| Left | 17 (18) | 21 (22) |
| Bilaterally | 44 (49) | 33 (36) |
| Comorbidity (yes), n (%)* | 20 (23) | 8 (9) |
| Physiotherapy at hospital (yes), n (%)* | 42 (47) | 68(74) |
| Physiotherapy at municipality (yes), n (%) | 61 (69) | 522 (57) |
| Physiotherapy in kindergarten (yes), n (%) | 34 (38) | 37 (40) |
| Walks independently, mean (SD) | 14.7 (3.3) | 14.1 (2.8) |
| Organized sports (yes), n (%) | 72 (81) | 78 (85) |
| Stretching | ||
| Daily first year, median (range) | 3 (1-9) | 3 (0-4) |
| Total years, mean (SD) | 5.7 (2.6) | 5.6 (2.4) |
| Heart failure | 2 | 0 |
| Asthma | 7 | 1 |
| Serious infections disease | 1 | 1 |
| Leg fracture | 1 | 1 |
| Congenial hips dysplasia | 3 | 0 |
| Comorbidity | 8.0 | 5.0 |
the number with bilateral involvement (p = 0.04) and comorbidity (p = 0.01) was higher in the traditional group and the number given physiotherapy at the hospital was higher in the Ponseti group (p < 0.01)
Between 2002 and 2003, most hospitals in Norway introduced the Ponseti method for treating clubfoot. The children were recruited from a multicentre clinical study, The Norwegian Clubfoot Study, conducted at four hospitals (Bergen, Trondheim, Stavanger and Oslo).13 None of the hospitals treated more than ten newborns with clubfoot yearly.
A total of 45 children without clubfoot, 22 boys and 23 girls (mean age 8.7, 7 to 9), were recruited from a school near Oslo University Hospital and included as a control group.14
Interventions
Patients treated with the traditional extensive surgery method had posterior or posteromedial release and an Achilles tendon lengthening.10 The Ponseti method included serial manipulations and castings beginning a few days after birth. Percutaneous tenotomy of the Achilles tendon was performed in most cases at the age of two to four months followed by two weeks casting. A foot abduction brace was applied thereafter and bracing was continued for four to five years. Long-term bracing is a mandatory and important part of the Ponseti programme.7
Demographics and outcome measures
Demographic characteristics included variables such as age, gender, age when walking independently, laterality (unilateral/ bilateral), whether major surgery was conducted, comorbidity and physiotherapy at the hospital (Table 1). Comorbidity indicates that the child has or had another disease that may influence motor ability, for example, previous leg fracture or infection after surgery, asthma or heart failure.
The MABC-212 is a revision of the Movement ABC15 and is one of the most widely used assessment tools in the field of Development Coordination Disorder.
A recent methodological study, assessing the intra- and intertester reliability of the MABC-2 in a healthy population, suggested that the MABC-2 might be more suitable for diagnostic or clinical decision-making purposes, than for evaluation of change over time.14
MABC-2 evaluates motor performance according to hand function, ball skills and balance (static and dynamic). The revised version makes it possible to identify and describe impairments in motor performance of children at the age of three to 16 years (divided into three age bands, 1: three to six years; 2: seven to ten years; and 3: 11 to 16 years). Scores can be used to identify children who are significantly behind their peers in motor development.12 The validity of the MABC-2 for the study group can be questioned but motor performance is an important domain for seven- to ten-year-old children and the total score has to be included for comparison with other groups of children, while dynamic and static balance is of particular interest for children with clubfoot. In order to test our hypotheses and compare results with children without motor abilities we applied the complete MABC-2 battery and specific scores to each domain including hand function and ball skills along with static and dynamic balance, particularly involving the lower limbs, along with the total scores.
There are eight items which are specific within each age band. For children aged seven to ten years these are: hand function or manual dexterity (placing pegs, threading lace and drawing trail), ball skills or aiming and catching (catching with two hands and throwing beanbags onto mats) and static and dynamic balance (one-board balance, walking heel- to- toe forwards and hopping on mats). It takes about 20 to 30 minutes to complete the test.
Age-adjusted standard scores and percentiles are provided for the three components of the battery and for the total score. The best score was used for data analysis when there were items with more than one test trial. Because two of the items, ‘placing pegs’ and ‘one-board balance’ involved testing of both preferred and non-preferred limbs, 11 raw item scores were obtained from a total of eight MABC-2 tasks.
On the basis of the raw scores, standard item scores, component standard scores, total test scores (TTS) and total standard scores (TSS) were calculated. In addition, the TSS was classified into: red zone (≤ fifth percentile): TTS ≤ 56 points; yellow zone (fifth and the 15th percentile): TTS 57-67; green zone (> 15th percentile) TTS > 67 points.16 Based on this, each child was categorized into one of three movement categories: green zone, no movement problems detected; yellow zone, potential motor problems; and red zone, impaired motor problems.
Procedure
Children were individually assessed with the MABC-2 in a suitable room. One physiotherapist (VSA) with more than 30 years of clinical experience examined all the children. The examiner was not blinded to the treatment given (Ponseti or traditional), but blinded to foot mobility because the patients wore shoes and the range of movement of the feet was not assessed.
Statistical analysis
Mean (sd), median (range), mean difference (95% confidence interval (CI)) or numbers (percentages) are given. We compared single item MABC-2 scores in children treated by the traditional method and the Ponseti method and for all children who had major surgery versus those who did not have major surgery, applying independent t -tests. Analysis of covariance (ANCOVA) was used as the primary analysis to compare scores in children treated by the traditional method and the Ponseti method. We adjusted for age, gender, age of walking independently, laterality (unilateral/ bilateral), major surgery, comorbidity, stretching, physiotherapy at the hospital, organized sport and major surgery. Similar adjustment was applied for evaluation of static and dynamic balance in patients with unilateral or bilateral involvement. Scores in the two-intervention group and the control group were compared using ANCOVA and Tukey’s post hoc test. We analyzed the number (percentages) of children in the three groups categorized as having normal motor function (green zone), clumsiness (yellow zone) or having motor problems (red zone) with the chi-squared test.
Results
Patient characteristics are described in Table 1. The number of patients with bilateral involvement and comorbidity was higher in the traditional group, while the number of physiotherapy receivers at hospital was higher in the Ponseti group (Table 1). The type of surgery performed is described in Table 2. More patients in the traditional group had major surgery (p < 0.001) and they were older at first surgery (p < 0.001). We found no significant difference in any of the MABC-2 scores comparing children with or without major surgery. The mean difference for balance standard score was -0.4 (95% CI -1.5 to 0.8, p = 0.53) and the mean difference for total standard score was -0.2 (-1.1 to 0.8, p = 0.74). The single items of the MABC-2 were not significantly different (Table 3). There was no difference between treatment groups in adjusted results in any of the MABC-2 categories or in the total score (Table 4). The control group had significantly better scores in all tests and the difference was largest for balance (p < 0.001) (Table 4 and Fig. 1). We found no significant (p = 0.39) difference in static and dynamic balance between the traditional and the Ponseti group (Table 4 and Fig. 1). In total, 71 (76%) patients in the Ponseti group and 68 patients in the traditional group (76%) had normal function (green zone) compared with 43 (96%) children in the control group (Table 5 and Fig.2). We found no significant (p = 0.56) difference in balance between patients with unilateral or bilateral involvement (Table 6). Of the adjusted variables, comorbidity (p-values from 0.001 to 0.039 for the different MABC-2 categories) and age when walking independently (p-values from 0.002 to 0.049 for the different MABC-2 categories except for the ball category) were significantly associated with results.
Table 2.
Surgery in the two groups. Values are numbers (percentages) unless stated otherwise
| Traditional (n = 89) | Ponseti (n = 93) | |
|---|---|---|
| First operation, type | ||
| None | 10 (11) | 14 (15) |
| Achillotomy* | 12 (13) | 79 (84) |
| Neonatal bilateral tendinotomy | 6 (7) | 0 |
| Achilles tendon lengthening | 8 (9) | 0 |
| Posterior release | 30 (34) | 1 (1) |
| Posteromedial release | 18 (20) | 0 |
| Tibialis anterior transposition | 2 (2) | 0 |
| Other open tendon operation | 3 (3) | 0 |
| Later operations | ||
| More than one operation | 45 (51) | 37 (39) |
| Number of total major operations* | 38 (43) 17 (19) |
11 (12) 1 (1) |
| Mean age in months (sd) at first operation* | 8.3 (15.3) | 2.2 (0.7) |
the number who had achillotomy was higher in the Ponseti group and the number of major operations and age was higher in the traditional group (p < 0.001).
Table 3.
Movement Assessment Battery for Children – Second Edition standard scores for single items in the traditional method and Ponseti method. Values are mean unadjusted scores (sd) in each group and mean unadjusted difference (95% confidence interval (CI)) between treatment groups. Independent t-tests were used to compare groups
| Traditional (n = 89) | Ponseti (n = 93) | Difference | 95% CI | p-value | |
|---|---|---|---|---|---|
| Hand | |||||
| Placing pegs | 9.0 (2.7) | 8.7 (2.6) | 0.2 | (-0.5 to 0.4) | 0.54 |
| Treading lace | 8.7 (2.7) | 8.9 (2.5) | 0.2 | (-1.0 to 0.5) | 0.59 |
| Drawing trail | 8,3 (3.2) | 8.3 (3.4) | 0.03 | (-0.9 to 1.0) | 0.95 |
| Ball | |||||
| Catching with two hands | 9,6 (2.8) | 9.6 (2.4) | 0.1 | (-0.8 to 0.7) | 0.86 |
| Throwing bean bag onto mat | 10.2 (2.7) | 10.2 (3.1) | 0.0 | (-0.8 to 0.8) | 0.99 |
| Static balance | |||||
| One-board balance | 10.2 (3.4) | 10.1 (2.8) | 0.03 | (-0.9 to 0.9) | 0.95 |
| Dynamic balance | |||||
| Walking heel-to-toe forwards | 8.5 (3.8) | 8.3 (3.7) | 0.2 | (-0.9 to 1.3) | 0.72 |
| Hopping on mats | 8.6 (3.5) | 9.2 (3.1) | 0.6 | (-1.6 to 0.4) | 0.23 |
Table 4.
Movement Assessment Battery for Children – Second Edition (MABC-2) scores in the traditional method and Ponseti method (n = 182) and controls (n = 45). Values are mean unadjusted scores (sd) in each group and mean adjusted* difference (95% confidence interval (CI)) between treatment groups. ANCOVA was used to compare groups
| Control (n = 45)** | Traditional (n = 89) | Ponseti (n = 93) | Adjusted difference | 95% CI | p-value | |
|---|---|---|---|---|---|---|
| Hand | ||||||
| Standard score | 10.0 (2.4) | 8.7 (2.9) | 8.7 (2.8) | 0.2 | (-0.7 to 1.2) | 0.63 |
| Percentile | 51.0 (25.6) | 38.6 (27.5) | 37.5 (27.2) | 2.9 | (-6.6 to 12.4) | 0.55 |
| Ball | ||||||
| Standard score | 11.7 (2.3) | 10.4 (3.0) | 10.4 (2.9) | 0.6 | (-0.4 to 1.6) | 0.26 |
| Percentile | 67.6 (23.0) | 52.2 (27.1) | 52.6 (26.7) | 6.0 | (-3.4 to 15.0) | 0.21 |
| Balance | ||||||
| Standard score | 12.5 (2.6) | 9.1 (3.9) | 9.1 (3.5) | 0.3 | (-1.0 to 1.6) | 0.62 |
| Percentile | 75.3 (25.0) | 44.4 (33.5) | 42.7 (31.6) | 4.5 | (-7.0 to 16.0) | 0.44 |
| Total | ||||||
| Test score | 85.0 (9.9) | 73.0 (16.5) | 73.2 (15.1) | 1.5 | (-3.8 to 6.8) | 0.58 |
| Standard score | 11.5 (2.4) | 9.0 (3.3) | 9.0 (3.1) | 0.5 | (-0.6 to 1.6) | 0.42 |
| Percentile | 66.6 (23.4) | 42.5 (30.5) | 41.3 (29.4) | 6.1 | (-4.3 to 16.6) | 0.25 |
adjusted for age, gender, laterality (unilaterally/bilaterally), major surgery (p > 0.3), co-morbidity (p < 0.05), physiotherapy at hospital and age of walking independently (p < 0.05 except for the ball category). P-values describes that co-morbidity and the age of walking independently (except for the ball category) were significantly associated with MABC-2 scores, but not treatment method and major surgery
hand and ball scores (p < 0.05) balance and total scores (p < 0.001) different from both treatment groups (p < 0.05)
Fig. 1.
Performance on the M-ABC-2, subtest Balance, for the Ponseti method (n = 93), traditional method (n = 89) and controls (n = 45).
Table 5.
Categorization according to motor function
| Normal motor function (green zone) | Clumsiness (yellow zone) | Motor problem (red zone) | |
|---|---|---|---|
| Traditional (n = 89), n (%) | 68 (76.9) | 6 (6.7) | 15 (16.9) |
| Ponseti (n = 93), n (%) | 71 (76.3) | 9 (9.7) | 13 (14) |
| Children without club foot (n = 45), n (%) | 43 (96) | 0 (0) | 2 (4) |
Fig. 2.
Performance on the M-ABC-2, total test, for the Ponseti method (n = 93), traditional method (n = 89) and controls (n = 45).
Table 6.
Mean unadjusted scores (sd) and adjusted differences (95% confidence interval) in balance between children with unilateral and bilateral clubfoot. ANCOVA was used to compare groups
| Unilateral (n = 105) |
Bilateral (n = 77) |
Difference* | p-value | |
|---|---|---|---|---|
| Standard score | 9.5 (3.4) | 8.6 (4.0) | 0.4 (-0.7 to 1.5) | 0.45 |
| Percentile | 46.2 (31.4) | 39.9 (33.7) | 2.9 (-7.0 to 12.8) | 0.56 |
adjusted for age, gender, treatment method, comorbidity (p = 0.01), major surgery, physiotherapy at the hospital and age of walking independently (p = 0.03). P-values describes that comorbidity and the age of walking independently were significantly associated with balance independent of unilateral or bilateral involvement
Discussion
We found that about three-quarters of children treated for idiopathic clubfoot had normal motor abilities at the age of nine years. Assessed with MABC-2 they had poorer mean motor abilities than children without clubfoot. The difference was largest for static and dynamic balance. By comparing the Ponseti method and traditional method we found no significant differences in any of the items or total scores. Findings in the present study comparing children with and without clubfoot are in agreement with results from most of the previously published smaller studies.2
The lack of difference between interventions at the age of nine years and the observation that three-quarters of the children had normal motor abilities, suggest that other factors play a role. Nevertheless, we were surprised that the Ponseti group, in which few children had no major surgery, did not have superior static and dynamic balance. The impact of treatment method and extended surgery may have larger impact on other outcomes and at an older age. Preferably long-term follow-up should be conducted both at adolescence and at adult age. In the adjusted analysis comorbidity and age when walking was significantly associated with almost all MABC-2 categories. Because numbers are small, this association should be interpreted with caution. However, in a recent study including patients with another type of deformity, idiopathic scoliosis, comorbidity was associated with reduced health-related quality of life.17 Limitations of the present study include the retrospective and non-randomized design and the use of a limited number of outcomes.
The strengths of the present study are the relatively large number of patients and the fact that few patients were lost to follow-up. All the children were aged between seven and ten years, and were tested by one experienced paediatric physical therapist (VSA) according to the same age-band of the MABC-2. The examiner was blinded to the children’s foot status including joint mobility, muscle function and movement quality and the treatment and clinical history of the patients.
The present study population was also included in the Norwegian multicentre study by Sætersdal et al,6 who assessed other outcomes and additional patients. They found that the traditional group had a statistically significant, but small reduction in range of movement. In addition, the parents of the children in the traditional group were less satisfied with outcome. We consider the difference in outcomes as interesting. Future studies should assess the long-term results and the association between outcomes. Different outcomes may be considered important for the child and its parents, the physiotherapist and the orthopaedic surgeon, respectively.
The introduction of the Ponseti method in Norway late in 2002 represents a major shift from extensive surgery to more conservative treatment. We had expected a difference in motor ability between the two interventions at the mean age of nine years, assuming that stiffer feet in children treated with the traditional method would play a role. Apparently, this did not influence the motor ability evaluated in this relatively large sample of children at the age of nine years but may have detrimental influence at an older age. Studies on motor abilities and athletic performance in children treated for idiopathic congenital clubfoot are rare and small. Andriesse et al2 included 20 children with clubfoot assessed with MABC. They found a difference in motor abilities, such as jumping, ball skills and one leg stand compared with normal values. Their findings are in line with the present study and support the conclusion that children with clubfoot should have more thorough neuromotor assessment.
Kenmoku et al3 reported that the athletic performance of primary school children with clubfoot was excellent with 96.6% performing above 2 sd of the average school child. Their conclusion was that children with satisfactory treated clubfoot did not have impaired athletic performance. However, analysis of the Z-scores for each event showed that clubfoot patients tended to perform well doing repetition side steps and relatively poorly at running and standing long jump. Despite reporting excellent performance, they found that children with clubfoot had problems transmitting power to the ground efficiently while moving straight ahead, because the pressure did not pass the great toe in the toe-off phase. When moving laterally they apparently transmit the power to the ground which might correlate with adduction of the forefoot.
Two small studies and a larger study suggest that physical performance in children with clubfoot is slightly decreased.5,18,19 The present study suggests various factors play a role in these children’s motor skills. The static balance item as one leg stand is a test for postural control incorporating both motor control and sensory and cognitive processes. The lack of difference between treatment groups may suggest that children with more stiffness in their ankle may compensate by e.g. flexing the hips or stretching the knees to obtain the balance.
Karol et al4 included 81 children with idiopathic clubfoot (29 treated with the Ponseti method, 23 with the French Physical Therapy method and 29 with surgical intervention before five years of age) in a non-randomized study. Participants were tested by both gait analyses and with the Peabody Developmental Motor Scale test. They found that the children treated non-operatively showed better function at five years of age. The Peabody Scale like the MABC-2 test does not comprise skills only for the lower limbs.
We reported that almost all the children participated in sports like football, handball, skiing and dancing. Unfortunately, we did not ask how frequently they performed the sport. Future studies should assess the frequency of participation in physical activities and sports and look at how this correlates with motor performance.
From a physiotherapeutic point of view, it would be preferable to test all children with clubfoot in kindergarten and at early school age in order to provide better motor training in those with motor problems or clumsiness. In kindergarten it is important to focus on activities that stimulate static and dynamic balance. The practice and experience of sports and daily activities is necessary to develop motor skill competence and social interactions required for well-being.20
Conclusion
We found that about three-quarters of children treated for idiopathic clubfoot had normal motor abilities at nine years of age. Comparable results were found in patients treated according to the traditional method and ad modus Ponseti method. We suggest that motor abilities should be assessed early to improve possible motor impairment in children with idiopathic clubfoot.
Acknowledgements
We want to thank the children and their parents who participated in the study. The authors also thank Inger Holm, Britt Stuge, Anne Therese Tveter, and Christian Sætersdal in planning of the study.
Compliance with ethical standards
Funding statement
Grant support was provided by the Sophies Minde Foundation, the Norwegian Fund for Postgraduate Training in Physiotherapy and the Clubfoot Association.
OA Licence Text
This article is distributed under the terms of the Creative Commons Attribution-Non Commercial 4.0 International (CC BY-NC 4.0) license (https://creativecommons.org/licenses/by-nc/4.0/) which permits non-commercial use, reproduction and distribution of the work without further permission provided the original work is attributed.
Ethical statement
Ethical approval: The study was approved by the Regional Committee for Medical and Health Research Ethics of Western-Norway (REK Vest), 2010/1882.
Informed consent: Written informed consent was obtained from the parents of all participants.
ICMJE Conflict of interest statement
None declared.
References
- 1.Gray K, Pacey V, Gibbons P, Little D, Burns J. Interventions for congenital talipes equinovarus (clubfoot). Cochrane Database Syst Rev 2014;8:CD008602. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Andriesse H, Westbom L, Hägglund G.. Motor ability in children treated for idiopathic clubfoot. A controlled pilot study. BMC Pediatr 2009;9:78. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 3.Kenmoku T, Kamegaya M, Saisu T, et al. Athletic ability of school-age children after satisfactory treatment of congenital clubfoot. J Pediatr Orthop 2013;33:321-325. [DOI] [PubMed] [Google Scholar]
- 4.Karol LA, Jeans KA, Kaipus KA. The relationship between gait, gross motor function, and parental perceived outcome in children with clubfeet. J Pediatr Orthop 2016;36:145-151. [DOI] [PubMed] [Google Scholar]
- 5.Lööf E, Andriesse H, André M, et al.. Gross motor skills in children with idiopathic clubfoot and the association between gross motor skills, foot involvement, gait, and foot motion. J Pediatr Orthop 2017;1. [DOI] [PubMed] [Google Scholar]
- 6.Sætersdal C, Fevang JM, Bjørlykke JA, Engesæter LB. Ponseti method compared to previous treatment of clubfoot in Norway. A multicenter study of 205 children followed for 8-11 years. J Child Orthop 2016;10:445-452. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 7.Ponseti IV. The ponseti technique for correction of congenital clubfoot. J Bone Joint Surg [Am] 2002;84-A:1889-1890; author reply 1890-1891. [DOI] [PubMed] [Google Scholar]
- 8.Morcuende JA, Dolan LA, Dietz FR, Ponseti IV. Radical reduction in the rate of extensive corrective surgery for clubfoot using the Ponseti method. Pediatrics 2004;113:376-380. [DOI] [PubMed] [Google Scholar]
- 9.Zionts LE, Zhao G, Hitchcock K, Maewal J, Ebramzadeh E. Has the rate of extensive surgery to treat idiopathic clubfoot declined in the United States? J Bone Joint Surg [Am] 2010;92-A:882-889. [DOI] [PubMed] [Google Scholar]
- 10.Turco VJ. Surgical correction of the resistant club foot. One-stage posteromedial release with internal fixation: a preliminary report. J Bone Joint Surg [Am] 1971;53-A:477-497. [PubMed] [Google Scholar]
- 11.Tashkandi MF, Tricco AC, Mamdani M, Jawadi A, Straus SE. Ponseti method for idiopathic congenital clubfoot in children. Cochrane Database Syst Rev 2012;10:CD010161. [Google Scholar]
- 12.Henderson SE, Sugden DA, Barnett AL. Movement assessment battery for children-2: Movement ABC-2. London: Psychological Corporation, 2007. [Google Scholar]
- 13.Sætersdal C, Fevang JM, Fosse L, Engesæter LB. Good results with the Ponseti method: a multicenter study of 162 clubfeet followed for 2-5 years. Acta Orthop 2012;83:288-293. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14.Holm I, Tveter AT, Aulie VS, Stuge B. High intra- and inter-rater chance variation of the movement assessment battery for children 2, ageband 2. Res Dev Disabil 2013;34:795-800. [DOI] [PubMed] [Google Scholar]
- 15.Henderson SE, Sugden DA, Barnett AL, Smits-Engelsman C.. Movement assessment battery for children. Manual. London: Psychological Corporation, 1992. [Google Scholar]
- 16.Smits-Engelsman BC, Niemeijer AS, van Waelvelde H.. Is the Movement Assessment Battery for Children-2nd edition a reliable instrument to measure motor performance in 3 year old children? Res Dev Disabil 2011;32:1370-1377. [DOI] [PubMed] [Google Scholar]
- 17.Brox JI, Lange JE, Steen H. Comorbidity influenced health-related quality of life of 390 patients with idiopathic scoliosis at long-term follow-up. Eur J Phys Rehabil Med 2014;50:73-81. [PubMed] [Google Scholar]
- 18.Church C, Coplan JA, Poljak D, et al. A comprehensive outcome comparison of surgical and Ponseti clubfoot treatments with reference to pediatric norms. J Child Orthop 2012;6:51-59. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 19.Lohle-Akkersdijk JJ, Rameckers EA, Andriesse H, de Reus I, van Erve RH. Walking capacity of children with clubfeet in primary school: something to worry about? J Pediatr Orthop B 2015;24:18-23 [DOI] [PubMed] [Google Scholar]
- 20.Skinner RA, Piek JP. Psychosocial implications of poor motor coordination in children and adolescents. Hum Mov Sci 2001;20:73-94. [DOI] [PubMed] [Google Scholar]